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Merge branch 'Improve error handling of verifier tests'
[linux-2.6-block.git] / fs / io_uring.c
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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Shared application/kernel submission and completion ring pairs, for
4 * supporting fast/efficient IO.
5 *
6 * A note on the read/write ordering memory barriers that are matched between
7 * the application and kernel side.
8 *
9 * After the application reads the CQ ring tail, it must use an
10 * appropriate smp_rmb() to pair with the smp_wmb() the kernel uses
11 * before writing the tail (using smp_load_acquire to read the tail will
12 * do). It also needs a smp_mb() before updating CQ head (ordering the
13 * entry load(s) with the head store), pairing with an implicit barrier
14 * through a control-dependency in io_get_cqring (smp_store_release to
15 * store head will do). Failure to do so could lead to reading invalid
16 * CQ entries.
17 *
18 * Likewise, the application must use an appropriate smp_wmb() before
19 * writing the SQ tail (ordering SQ entry stores with the tail store),
20 * which pairs with smp_load_acquire in io_get_sqring (smp_store_release
21 * to store the tail will do). And it needs a barrier ordering the SQ
22 * head load before writing new SQ entries (smp_load_acquire to read
23 * head will do).
24 *
25 * When using the SQ poll thread (IORING_SETUP_SQPOLL), the application
26 * needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after*
27 * updating the SQ tail; a full memory barrier smp_mb() is needed
28 * between.
29 *
30 * Also see the examples in the liburing library:
31 *
32 * git://git.kernel.dk/liburing
33 *
34 * io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens
35 * from data shared between the kernel and application. This is done both
36 * for ordering purposes, but also to ensure that once a value is loaded from
37 * data that the application could potentially modify, it remains stable.
38 *
39 * Copyright (C) 2018-2019 Jens Axboe
40 * Copyright (c) 2018-2019 Christoph Hellwig
41 */
42#include <linux/kernel.h>
43#include <linux/init.h>
44#include <linux/errno.h>
45#include <linux/syscalls.h>
46#include <linux/compat.h>
47#include <net/compat.h>
48#include <linux/refcount.h>
49#include <linux/uio.h>
50#include <linux/bits.h>
51
52#include <linux/sched/signal.h>
53#include <linux/fs.h>
54#include <linux/file.h>
55#include <linux/fdtable.h>
56#include <linux/mm.h>
57#include <linux/mman.h>
58#include <linux/percpu.h>
59#include <linux/slab.h>
60#include <linux/kthread.h>
61#include <linux/blkdev.h>
62#include <linux/bvec.h>
63#include <linux/net.h>
64#include <net/sock.h>
65#include <net/af_unix.h>
66#include <net/scm.h>
67#include <linux/anon_inodes.h>
68#include <linux/sched/mm.h>
69#include <linux/uaccess.h>
70#include <linux/nospec.h>
71#include <linux/sizes.h>
72#include <linux/hugetlb.h>
73#include <linux/highmem.h>
74#include <linux/namei.h>
75#include <linux/fsnotify.h>
76#include <linux/fadvise.h>
77#include <linux/eventpoll.h>
78#include <linux/fs_struct.h>
79#include <linux/splice.h>
80#include <linux/task_work.h>
81#include <linux/pagemap.h>
82#include <linux/io_uring.h>
83#include <linux/blk-cgroup.h>
84#include <linux/audit.h>
85
86#define CREATE_TRACE_POINTS
87#include <trace/events/io_uring.h>
88
89#include <uapi/linux/io_uring.h>
90
91#include "internal.h"
92#include "io-wq.h"
93
94#define IORING_MAX_ENTRIES 32768
95#define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES)
96
97/*
98 * Shift of 9 is 512 entries, or exactly one page on 64-bit archs
99 */
100#define IORING_FILE_TABLE_SHIFT 9
101#define IORING_MAX_FILES_TABLE (1U << IORING_FILE_TABLE_SHIFT)
102#define IORING_FILE_TABLE_MASK (IORING_MAX_FILES_TABLE - 1)
103#define IORING_MAX_FIXED_FILES (64 * IORING_MAX_FILES_TABLE)
104#define IORING_MAX_RESTRICTIONS (IORING_RESTRICTION_LAST + \
105 IORING_REGISTER_LAST + IORING_OP_LAST)
106
107struct io_uring {
108 u32 head ____cacheline_aligned_in_smp;
109 u32 tail ____cacheline_aligned_in_smp;
110};
111
112/*
113 * This data is shared with the application through the mmap at offsets
114 * IORING_OFF_SQ_RING and IORING_OFF_CQ_RING.
115 *
116 * The offsets to the member fields are published through struct
117 * io_sqring_offsets when calling io_uring_setup.
118 */
119struct io_rings {
120 /*
121 * Head and tail offsets into the ring; the offsets need to be
122 * masked to get valid indices.
123 *
124 * The kernel controls head of the sq ring and the tail of the cq ring,
125 * and the application controls tail of the sq ring and the head of the
126 * cq ring.
127 */
128 struct io_uring sq, cq;
129 /*
130 * Bitmasks to apply to head and tail offsets (constant, equals
131 * ring_entries - 1)
132 */
133 u32 sq_ring_mask, cq_ring_mask;
134 /* Ring sizes (constant, power of 2) */
135 u32 sq_ring_entries, cq_ring_entries;
136 /*
137 * Number of invalid entries dropped by the kernel due to
138 * invalid index stored in array
139 *
140 * Written by the kernel, shouldn't be modified by the
141 * application (i.e. get number of "new events" by comparing to
142 * cached value).
143 *
144 * After a new SQ head value was read by the application this
145 * counter includes all submissions that were dropped reaching
146 * the new SQ head (and possibly more).
147 */
148 u32 sq_dropped;
149 /*
150 * Runtime SQ flags
151 *
152 * Written by the kernel, shouldn't be modified by the
153 * application.
154 *
155 * The application needs a full memory barrier before checking
156 * for IORING_SQ_NEED_WAKEUP after updating the sq tail.
157 */
158 u32 sq_flags;
159 /*
160 * Runtime CQ flags
161 *
162 * Written by the application, shouldn't be modified by the
163 * kernel.
164 */
165 u32 cq_flags;
166 /*
167 * Number of completion events lost because the queue was full;
168 * this should be avoided by the application by making sure
169 * there are not more requests pending than there is space in
170 * the completion queue.
171 *
172 * Written by the kernel, shouldn't be modified by the
173 * application (i.e. get number of "new events" by comparing to
174 * cached value).
175 *
176 * As completion events come in out of order this counter is not
177 * ordered with any other data.
178 */
179 u32 cq_overflow;
180 /*
181 * Ring buffer of completion events.
182 *
183 * The kernel writes completion events fresh every time they are
184 * produced, so the application is allowed to modify pending
185 * entries.
186 */
187 struct io_uring_cqe cqes[] ____cacheline_aligned_in_smp;
188};
189
190struct io_mapped_ubuf {
191 u64 ubuf;
192 size_t len;
193 struct bio_vec *bvec;
194 unsigned int nr_bvecs;
195 unsigned long acct_pages;
196};
197
198struct fixed_file_table {
199 struct file **files;
200};
201
202struct fixed_file_ref_node {
203 struct percpu_ref refs;
204 struct list_head node;
205 struct list_head file_list;
206 struct fixed_file_data *file_data;
207 struct llist_node llist;
208 bool done;
209};
210
211struct fixed_file_data {
212 struct fixed_file_table *table;
213 struct io_ring_ctx *ctx;
214
215 struct fixed_file_ref_node *node;
216 struct percpu_ref refs;
217 struct completion done;
218 struct list_head ref_list;
219 spinlock_t lock;
220};
221
222struct io_buffer {
223 struct list_head list;
224 __u64 addr;
225 __s32 len;
226 __u16 bid;
227};
228
229struct io_restriction {
230 DECLARE_BITMAP(register_op, IORING_REGISTER_LAST);
231 DECLARE_BITMAP(sqe_op, IORING_OP_LAST);
232 u8 sqe_flags_allowed;
233 u8 sqe_flags_required;
234 bool registered;
235};
236
237struct io_sq_data {
238 refcount_t refs;
239 struct mutex lock;
240
241 /* ctx's that are using this sqd */
242 struct list_head ctx_list;
243 struct list_head ctx_new_list;
244 struct mutex ctx_lock;
245
246 struct task_struct *thread;
247 struct wait_queue_head wait;
248};
249
250struct io_ring_ctx {
251 struct {
252 struct percpu_ref refs;
253 } ____cacheline_aligned_in_smp;
254
255 struct {
256 unsigned int flags;
257 unsigned int compat: 1;
258 unsigned int limit_mem: 1;
259 unsigned int cq_overflow_flushed: 1;
260 unsigned int drain_next: 1;
261 unsigned int eventfd_async: 1;
262 unsigned int restricted: 1;
263
264 /*
265 * Ring buffer of indices into array of io_uring_sqe, which is
266 * mmapped by the application using the IORING_OFF_SQES offset.
267 *
268 * This indirection could e.g. be used to assign fixed
269 * io_uring_sqe entries to operations and only submit them to
270 * the queue when needed.
271 *
272 * The kernel modifies neither the indices array nor the entries
273 * array.
274 */
275 u32 *sq_array;
276 unsigned cached_sq_head;
277 unsigned sq_entries;
278 unsigned sq_mask;
279 unsigned sq_thread_idle;
280 unsigned cached_sq_dropped;
281 unsigned cached_cq_overflow;
282 unsigned long sq_check_overflow;
283
284 struct list_head defer_list;
285 struct list_head timeout_list;
286 struct list_head cq_overflow_list;
287
288 wait_queue_head_t inflight_wait;
289 struct io_uring_sqe *sq_sqes;
290 } ____cacheline_aligned_in_smp;
291
292 struct io_rings *rings;
293
294 /* IO offload */
295 struct io_wq *io_wq;
296
297 /*
298 * For SQPOLL usage - we hold a reference to the parent task, so we
299 * have access to the ->files
300 */
301 struct task_struct *sqo_task;
302
303 /* Only used for accounting purposes */
304 struct mm_struct *mm_account;
305
306#ifdef CONFIG_BLK_CGROUP
307 struct cgroup_subsys_state *sqo_blkcg_css;
308#endif
309
310 struct io_sq_data *sq_data; /* if using sq thread polling */
311
312 struct wait_queue_head sqo_sq_wait;
313 struct wait_queue_entry sqo_wait_entry;
314 struct list_head sqd_list;
315
316 /*
317 * If used, fixed file set. Writers must ensure that ->refs is dead,
318 * readers must ensure that ->refs is alive as long as the file* is
319 * used. Only updated through io_uring_register(2).
320 */
321 struct fixed_file_data *file_data;
322 unsigned nr_user_files;
323
324 /* if used, fixed mapped user buffers */
325 unsigned nr_user_bufs;
326 struct io_mapped_ubuf *user_bufs;
327
328 struct user_struct *user;
329
330 const struct cred *creds;
331
332#ifdef CONFIG_AUDIT
333 kuid_t loginuid;
334 unsigned int sessionid;
335#endif
336
337 struct completion ref_comp;
338 struct completion sq_thread_comp;
339
340 /* if all else fails... */
341 struct io_kiocb *fallback_req;
342
343#if defined(CONFIG_UNIX)
344 struct socket *ring_sock;
345#endif
346
347 struct idr io_buffer_idr;
348
349 struct idr personality_idr;
350
351 struct {
352 unsigned cached_cq_tail;
353 unsigned cq_entries;
354 unsigned cq_mask;
355 atomic_t cq_timeouts;
356 unsigned long cq_check_overflow;
357 struct wait_queue_head cq_wait;
358 struct fasync_struct *cq_fasync;
359 struct eventfd_ctx *cq_ev_fd;
360 } ____cacheline_aligned_in_smp;
361
362 struct {
363 struct mutex uring_lock;
364 wait_queue_head_t wait;
365 } ____cacheline_aligned_in_smp;
366
367 struct {
368 spinlock_t completion_lock;
369
370 /*
371 * ->iopoll_list is protected by the ctx->uring_lock for
372 * io_uring instances that don't use IORING_SETUP_SQPOLL.
373 * For SQPOLL, only the single threaded io_sq_thread() will
374 * manipulate the list, hence no extra locking is needed there.
375 */
376 struct list_head iopoll_list;
377 struct hlist_head *cancel_hash;
378 unsigned cancel_hash_bits;
379 bool poll_multi_file;
380
381 spinlock_t inflight_lock;
382 struct list_head inflight_list;
383 } ____cacheline_aligned_in_smp;
384
385 struct delayed_work file_put_work;
386 struct llist_head file_put_llist;
387
388 struct work_struct exit_work;
389 struct io_restriction restrictions;
390};
391
392/*
393 * First field must be the file pointer in all the
394 * iocb unions! See also 'struct kiocb' in <linux/fs.h>
395 */
396struct io_poll_iocb {
397 struct file *file;
398 union {
399 struct wait_queue_head *head;
400 u64 addr;
401 };
402 __poll_t events;
403 bool done;
404 bool canceled;
405 struct wait_queue_entry wait;
406};
407
408struct io_close {
409 struct file *file;
410 struct file *put_file;
411 int fd;
412};
413
414struct io_timeout_data {
415 struct io_kiocb *req;
416 struct hrtimer timer;
417 struct timespec64 ts;
418 enum hrtimer_mode mode;
419};
420
421struct io_accept {
422 struct file *file;
423 struct sockaddr __user *addr;
424 int __user *addr_len;
425 int flags;
426 unsigned long nofile;
427};
428
429struct io_sync {
430 struct file *file;
431 loff_t len;
432 loff_t off;
433 int flags;
434 int mode;
435};
436
437struct io_cancel {
438 struct file *file;
439 u64 addr;
440};
441
442struct io_timeout {
443 struct file *file;
444 u32 off;
445 u32 target_seq;
446 struct list_head list;
447};
448
449struct io_timeout_rem {
450 struct file *file;
451 u64 addr;
452};
453
454struct io_rw {
455 /* NOTE: kiocb has the file as the first member, so don't do it here */
456 struct kiocb kiocb;
457 u64 addr;
458 u64 len;
459};
460
461struct io_connect {
462 struct file *file;
463 struct sockaddr __user *addr;
464 int addr_len;
465};
466
467struct io_sr_msg {
468 struct file *file;
469 union {
470 struct user_msghdr __user *umsg;
471 void __user *buf;
472 };
473 int msg_flags;
474 int bgid;
475 size_t len;
476 struct io_buffer *kbuf;
477};
478
479struct io_open {
480 struct file *file;
481 int dfd;
482 bool ignore_nonblock;
483 struct filename *filename;
484 struct open_how how;
485 unsigned long nofile;
486};
487
488struct io_files_update {
489 struct file *file;
490 u64 arg;
491 u32 nr_args;
492 u32 offset;
493};
494
495struct io_fadvise {
496 struct file *file;
497 u64 offset;
498 u32 len;
499 u32 advice;
500};
501
502struct io_madvise {
503 struct file *file;
504 u64 addr;
505 u32 len;
506 u32 advice;
507};
508
509struct io_epoll {
510 struct file *file;
511 int epfd;
512 int op;
513 int fd;
514 struct epoll_event event;
515};
516
517struct io_splice {
518 struct file *file_out;
519 struct file *file_in;
520 loff_t off_out;
521 loff_t off_in;
522 u64 len;
523 unsigned int flags;
524};
525
526struct io_provide_buf {
527 struct file *file;
528 __u64 addr;
529 __s32 len;
530 __u32 bgid;
531 __u16 nbufs;
532 __u16 bid;
533};
534
535struct io_statx {
536 struct file *file;
537 int dfd;
538 unsigned int mask;
539 unsigned int flags;
540 const char __user *filename;
541 struct statx __user *buffer;
542};
543
544struct io_completion {
545 struct file *file;
546 struct list_head list;
547 int cflags;
548};
549
550struct io_async_connect {
551 struct sockaddr_storage address;
552};
553
554struct io_async_msghdr {
555 struct iovec fast_iov[UIO_FASTIOV];
556 struct iovec *iov;
557 struct sockaddr __user *uaddr;
558 struct msghdr msg;
559 struct sockaddr_storage addr;
560};
561
562struct io_async_rw {
563 struct iovec fast_iov[UIO_FASTIOV];
564 const struct iovec *free_iovec;
565 struct iov_iter iter;
566 size_t bytes_done;
567 struct wait_page_queue wpq;
568};
569
570enum {
571 REQ_F_FIXED_FILE_BIT = IOSQE_FIXED_FILE_BIT,
572 REQ_F_IO_DRAIN_BIT = IOSQE_IO_DRAIN_BIT,
573 REQ_F_LINK_BIT = IOSQE_IO_LINK_BIT,
574 REQ_F_HARDLINK_BIT = IOSQE_IO_HARDLINK_BIT,
575 REQ_F_FORCE_ASYNC_BIT = IOSQE_ASYNC_BIT,
576 REQ_F_BUFFER_SELECT_BIT = IOSQE_BUFFER_SELECT_BIT,
577
578 REQ_F_LINK_HEAD_BIT,
579 REQ_F_FAIL_LINK_BIT,
580 REQ_F_INFLIGHT_BIT,
581 REQ_F_CUR_POS_BIT,
582 REQ_F_NOWAIT_BIT,
583 REQ_F_LINK_TIMEOUT_BIT,
584 REQ_F_ISREG_BIT,
585 REQ_F_NEED_CLEANUP_BIT,
586 REQ_F_POLLED_BIT,
587 REQ_F_BUFFER_SELECTED_BIT,
588 REQ_F_NO_FILE_TABLE_BIT,
589 REQ_F_WORK_INITIALIZED_BIT,
590 REQ_F_LTIMEOUT_ACTIVE_BIT,
591
592 /* not a real bit, just to check we're not overflowing the space */
593 __REQ_F_LAST_BIT,
594};
595
596enum {
597 /* ctx owns file */
598 REQ_F_FIXED_FILE = BIT(REQ_F_FIXED_FILE_BIT),
599 /* drain existing IO first */
600 REQ_F_IO_DRAIN = BIT(REQ_F_IO_DRAIN_BIT),
601 /* linked sqes */
602 REQ_F_LINK = BIT(REQ_F_LINK_BIT),
603 /* doesn't sever on completion < 0 */
604 REQ_F_HARDLINK = BIT(REQ_F_HARDLINK_BIT),
605 /* IOSQE_ASYNC */
606 REQ_F_FORCE_ASYNC = BIT(REQ_F_FORCE_ASYNC_BIT),
607 /* IOSQE_BUFFER_SELECT */
608 REQ_F_BUFFER_SELECT = BIT(REQ_F_BUFFER_SELECT_BIT),
609
610 /* head of a link */
611 REQ_F_LINK_HEAD = BIT(REQ_F_LINK_HEAD_BIT),
612 /* fail rest of links */
613 REQ_F_FAIL_LINK = BIT(REQ_F_FAIL_LINK_BIT),
614 /* on inflight list */
615 REQ_F_INFLIGHT = BIT(REQ_F_INFLIGHT_BIT),
616 /* read/write uses file position */
617 REQ_F_CUR_POS = BIT(REQ_F_CUR_POS_BIT),
618 /* must not punt to workers */
619 REQ_F_NOWAIT = BIT(REQ_F_NOWAIT_BIT),
620 /* has or had linked timeout */
621 REQ_F_LINK_TIMEOUT = BIT(REQ_F_LINK_TIMEOUT_BIT),
622 /* regular file */
623 REQ_F_ISREG = BIT(REQ_F_ISREG_BIT),
624 /* needs cleanup */
625 REQ_F_NEED_CLEANUP = BIT(REQ_F_NEED_CLEANUP_BIT),
626 /* already went through poll handler */
627 REQ_F_POLLED = BIT(REQ_F_POLLED_BIT),
628 /* buffer already selected */
629 REQ_F_BUFFER_SELECTED = BIT(REQ_F_BUFFER_SELECTED_BIT),
630 /* doesn't need file table for this request */
631 REQ_F_NO_FILE_TABLE = BIT(REQ_F_NO_FILE_TABLE_BIT),
632 /* io_wq_work is initialized */
633 REQ_F_WORK_INITIALIZED = BIT(REQ_F_WORK_INITIALIZED_BIT),
634 /* linked timeout is active, i.e. prepared by link's head */
635 REQ_F_LTIMEOUT_ACTIVE = BIT(REQ_F_LTIMEOUT_ACTIVE_BIT),
636};
637
638struct async_poll {
639 struct io_poll_iocb poll;
640 struct io_poll_iocb *double_poll;
641};
642
643/*
644 * NOTE! Each of the iocb union members has the file pointer
645 * as the first entry in their struct definition. So you can
646 * access the file pointer through any of the sub-structs,
647 * or directly as just 'ki_filp' in this struct.
648 */
649struct io_kiocb {
650 union {
651 struct file *file;
652 struct io_rw rw;
653 struct io_poll_iocb poll;
654 struct io_accept accept;
655 struct io_sync sync;
656 struct io_cancel cancel;
657 struct io_timeout timeout;
658 struct io_timeout_rem timeout_rem;
659 struct io_connect connect;
660 struct io_sr_msg sr_msg;
661 struct io_open open;
662 struct io_close close;
663 struct io_files_update files_update;
664 struct io_fadvise fadvise;
665 struct io_madvise madvise;
666 struct io_epoll epoll;
667 struct io_splice splice;
668 struct io_provide_buf pbuf;
669 struct io_statx statx;
670 /* use only after cleaning per-op data, see io_clean_op() */
671 struct io_completion compl;
672 };
673
674 /* opcode allocated if it needs to store data for async defer */
675 void *async_data;
676 u8 opcode;
677 /* polled IO has completed */
678 u8 iopoll_completed;
679
680 u16 buf_index;
681 u32 result;
682
683 struct io_ring_ctx *ctx;
684 unsigned int flags;
685 refcount_t refs;
686 struct task_struct *task;
687 u64 user_data;
688
689 struct list_head link_list;
690
691 /*
692 * 1. used with ctx->iopoll_list with reads/writes
693 * 2. to track reqs with ->files (see io_op_def::file_table)
694 */
695 struct list_head inflight_entry;
696
697 struct percpu_ref *fixed_file_refs;
698 struct callback_head task_work;
699 /* for polled requests, i.e. IORING_OP_POLL_ADD and async armed poll */
700 struct hlist_node hash_node;
701 struct async_poll *apoll;
702 struct io_wq_work work;
703};
704
705struct io_defer_entry {
706 struct list_head list;
707 struct io_kiocb *req;
708 u32 seq;
709};
710
711#define IO_IOPOLL_BATCH 8
712
713struct io_comp_state {
714 unsigned int nr;
715 struct list_head list;
716 struct io_ring_ctx *ctx;
717};
718
719struct io_submit_state {
720 struct blk_plug plug;
721
722 /*
723 * io_kiocb alloc cache
724 */
725 void *reqs[IO_IOPOLL_BATCH];
726 unsigned int free_reqs;
727
728 /*
729 * Batch completion logic
730 */
731 struct io_comp_state comp;
732
733 /*
734 * File reference cache
735 */
736 struct file *file;
737 unsigned int fd;
738 unsigned int has_refs;
739 unsigned int ios_left;
740};
741
742struct io_op_def {
743 /* needs req->file assigned */
744 unsigned needs_file : 1;
745 /* don't fail if file grab fails */
746 unsigned needs_file_no_error : 1;
747 /* hash wq insertion if file is a regular file */
748 unsigned hash_reg_file : 1;
749 /* unbound wq insertion if file is a non-regular file */
750 unsigned unbound_nonreg_file : 1;
751 /* opcode is not supported by this kernel */
752 unsigned not_supported : 1;
753 /* set if opcode supports polled "wait" */
754 unsigned pollin : 1;
755 unsigned pollout : 1;
756 /* op supports buffer selection */
757 unsigned buffer_select : 1;
758 /* must always have async data allocated */
759 unsigned needs_async_data : 1;
760 /* size of async data needed, if any */
761 unsigned short async_size;
762 unsigned work_flags;
763};
764
765static const struct io_op_def io_op_defs[] = {
766 [IORING_OP_NOP] = {},
767 [IORING_OP_READV] = {
768 .needs_file = 1,
769 .unbound_nonreg_file = 1,
770 .pollin = 1,
771 .buffer_select = 1,
772 .needs_async_data = 1,
773 .async_size = sizeof(struct io_async_rw),
774 .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG,
775 },
776 [IORING_OP_WRITEV] = {
777 .needs_file = 1,
778 .hash_reg_file = 1,
779 .unbound_nonreg_file = 1,
780 .pollout = 1,
781 .needs_async_data = 1,
782 .async_size = sizeof(struct io_async_rw),
783 .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG |
784 IO_WQ_WORK_FSIZE,
785 },
786 [IORING_OP_FSYNC] = {
787 .needs_file = 1,
788 .work_flags = IO_WQ_WORK_BLKCG,
789 },
790 [IORING_OP_READ_FIXED] = {
791 .needs_file = 1,
792 .unbound_nonreg_file = 1,
793 .pollin = 1,
794 .async_size = sizeof(struct io_async_rw),
795 .work_flags = IO_WQ_WORK_BLKCG | IO_WQ_WORK_MM,
796 },
797 [IORING_OP_WRITE_FIXED] = {
798 .needs_file = 1,
799 .hash_reg_file = 1,
800 .unbound_nonreg_file = 1,
801 .pollout = 1,
802 .async_size = sizeof(struct io_async_rw),
803 .work_flags = IO_WQ_WORK_BLKCG | IO_WQ_WORK_FSIZE |
804 IO_WQ_WORK_MM,
805 },
806 [IORING_OP_POLL_ADD] = {
807 .needs_file = 1,
808 .unbound_nonreg_file = 1,
809 },
810 [IORING_OP_POLL_REMOVE] = {},
811 [IORING_OP_SYNC_FILE_RANGE] = {
812 .needs_file = 1,
813 .work_flags = IO_WQ_WORK_BLKCG,
814 },
815 [IORING_OP_SENDMSG] = {
816 .needs_file = 1,
817 .unbound_nonreg_file = 1,
818 .pollout = 1,
819 .needs_async_data = 1,
820 .async_size = sizeof(struct io_async_msghdr),
821 .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG |
822 IO_WQ_WORK_FS,
823 },
824 [IORING_OP_RECVMSG] = {
825 .needs_file = 1,
826 .unbound_nonreg_file = 1,
827 .pollin = 1,
828 .buffer_select = 1,
829 .needs_async_data = 1,
830 .async_size = sizeof(struct io_async_msghdr),
831 .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG |
832 IO_WQ_WORK_FS,
833 },
834 [IORING_OP_TIMEOUT] = {
835 .needs_async_data = 1,
836 .async_size = sizeof(struct io_timeout_data),
837 .work_flags = IO_WQ_WORK_MM,
838 },
839 [IORING_OP_TIMEOUT_REMOVE] = {},
840 [IORING_OP_ACCEPT] = {
841 .needs_file = 1,
842 .unbound_nonreg_file = 1,
843 .pollin = 1,
844 .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_FILES,
845 },
846 [IORING_OP_ASYNC_CANCEL] = {},
847 [IORING_OP_LINK_TIMEOUT] = {
848 .needs_async_data = 1,
849 .async_size = sizeof(struct io_timeout_data),
850 .work_flags = IO_WQ_WORK_MM,
851 },
852 [IORING_OP_CONNECT] = {
853 .needs_file = 1,
854 .unbound_nonreg_file = 1,
855 .pollout = 1,
856 .needs_async_data = 1,
857 .async_size = sizeof(struct io_async_connect),
858 .work_flags = IO_WQ_WORK_MM,
859 },
860 [IORING_OP_FALLOCATE] = {
861 .needs_file = 1,
862 .work_flags = IO_WQ_WORK_BLKCG | IO_WQ_WORK_FSIZE,
863 },
864 [IORING_OP_OPENAT] = {
865 .work_flags = IO_WQ_WORK_FILES | IO_WQ_WORK_BLKCG |
866 IO_WQ_WORK_FS,
867 },
868 [IORING_OP_CLOSE] = {
869 .needs_file = 1,
870 .needs_file_no_error = 1,
871 .work_flags = IO_WQ_WORK_FILES | IO_WQ_WORK_BLKCG,
872 },
873 [IORING_OP_FILES_UPDATE] = {
874 .work_flags = IO_WQ_WORK_FILES | IO_WQ_WORK_MM,
875 },
876 [IORING_OP_STATX] = {
877 .work_flags = IO_WQ_WORK_FILES | IO_WQ_WORK_MM |
878 IO_WQ_WORK_FS | IO_WQ_WORK_BLKCG,
879 },
880 [IORING_OP_READ] = {
881 .needs_file = 1,
882 .unbound_nonreg_file = 1,
883 .pollin = 1,
884 .buffer_select = 1,
885 .async_size = sizeof(struct io_async_rw),
886 .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG,
887 },
888 [IORING_OP_WRITE] = {
889 .needs_file = 1,
890 .unbound_nonreg_file = 1,
891 .pollout = 1,
892 .async_size = sizeof(struct io_async_rw),
893 .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG |
894 IO_WQ_WORK_FSIZE,
895 },
896 [IORING_OP_FADVISE] = {
897 .needs_file = 1,
898 .work_flags = IO_WQ_WORK_BLKCG,
899 },
900 [IORING_OP_MADVISE] = {
901 .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG,
902 },
903 [IORING_OP_SEND] = {
904 .needs_file = 1,
905 .unbound_nonreg_file = 1,
906 .pollout = 1,
907 .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG,
908 },
909 [IORING_OP_RECV] = {
910 .needs_file = 1,
911 .unbound_nonreg_file = 1,
912 .pollin = 1,
913 .buffer_select = 1,
914 .work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG,
915 },
916 [IORING_OP_OPENAT2] = {
917 .work_flags = IO_WQ_WORK_FILES | IO_WQ_WORK_FS |
918 IO_WQ_WORK_BLKCG,
919 },
920 [IORING_OP_EPOLL_CTL] = {
921 .unbound_nonreg_file = 1,
922 .work_flags = IO_WQ_WORK_FILES,
923 },
924 [IORING_OP_SPLICE] = {
925 .needs_file = 1,
926 .hash_reg_file = 1,
927 .unbound_nonreg_file = 1,
928 .work_flags = IO_WQ_WORK_BLKCG,
929 },
930 [IORING_OP_PROVIDE_BUFFERS] = {},
931 [IORING_OP_REMOVE_BUFFERS] = {},
932 [IORING_OP_TEE] = {
933 .needs_file = 1,
934 .hash_reg_file = 1,
935 .unbound_nonreg_file = 1,
936 },
937};
938
939enum io_mem_account {
940 ACCT_LOCKED,
941 ACCT_PINNED,
942};
943
944static void __io_complete_rw(struct io_kiocb *req, long res, long res2,
945 struct io_comp_state *cs);
946static void io_cqring_fill_event(struct io_kiocb *req, long res);
947static void io_put_req(struct io_kiocb *req);
948static void io_put_req_deferred(struct io_kiocb *req, int nr);
949static void io_double_put_req(struct io_kiocb *req);
950static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req);
951static void __io_queue_linked_timeout(struct io_kiocb *req);
952static void io_queue_linked_timeout(struct io_kiocb *req);
953static int __io_sqe_files_update(struct io_ring_ctx *ctx,
954 struct io_uring_files_update *ip,
955 unsigned nr_args);
956static void __io_clean_op(struct io_kiocb *req);
957static struct file *io_file_get(struct io_submit_state *state,
958 struct io_kiocb *req, int fd, bool fixed);
959static void __io_queue_sqe(struct io_kiocb *req, struct io_comp_state *cs);
960static void io_file_put_work(struct work_struct *work);
961
962static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
963 struct iovec **iovec, struct iov_iter *iter,
964 bool needs_lock);
965static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec,
966 const struct iovec *fast_iov,
967 struct iov_iter *iter, bool force);
968
969static struct kmem_cache *req_cachep;
970
971static const struct file_operations io_uring_fops;
972
973struct sock *io_uring_get_socket(struct file *file)
974{
975#if defined(CONFIG_UNIX)
976 if (file->f_op == &io_uring_fops) {
977 struct io_ring_ctx *ctx = file->private_data;
978
979 return ctx->ring_sock->sk;
980 }
981#endif
982 return NULL;
983}
984EXPORT_SYMBOL(io_uring_get_socket);
985
986static inline void io_clean_op(struct io_kiocb *req)
987{
988 if (req->flags & (REQ_F_NEED_CLEANUP | REQ_F_BUFFER_SELECTED |
989 REQ_F_INFLIGHT))
990 __io_clean_op(req);
991}
992
993static void io_sq_thread_drop_mm(void)
994{
995 struct mm_struct *mm = current->mm;
996
997 if (mm) {
998 kthread_unuse_mm(mm);
999 mmput(mm);
1000 current->mm = NULL;
1001 }
1002}
1003
1004static int __io_sq_thread_acquire_mm(struct io_ring_ctx *ctx)
1005{
1006 struct mm_struct *mm;
1007
1008 if (current->mm)
1009 return 0;
1010
1011 /* Should never happen */
1012 if (unlikely(!(ctx->flags & IORING_SETUP_SQPOLL)))
1013 return -EFAULT;
1014
1015 task_lock(ctx->sqo_task);
1016 mm = ctx->sqo_task->mm;
1017 if (unlikely(!mm || !mmget_not_zero(mm)))
1018 mm = NULL;
1019 task_unlock(ctx->sqo_task);
1020
1021 if (mm) {
1022 kthread_use_mm(mm);
1023 return 0;
1024 }
1025
1026 return -EFAULT;
1027}
1028
1029static int io_sq_thread_acquire_mm(struct io_ring_ctx *ctx,
1030 struct io_kiocb *req)
1031{
1032 if (!(io_op_defs[req->opcode].work_flags & IO_WQ_WORK_MM))
1033 return 0;
1034 return __io_sq_thread_acquire_mm(ctx);
1035}
1036
1037static void io_sq_thread_associate_blkcg(struct io_ring_ctx *ctx,
1038 struct cgroup_subsys_state **cur_css)
1039
1040{
1041#ifdef CONFIG_BLK_CGROUP
1042 /* puts the old one when swapping */
1043 if (*cur_css != ctx->sqo_blkcg_css) {
1044 kthread_associate_blkcg(ctx->sqo_blkcg_css);
1045 *cur_css = ctx->sqo_blkcg_css;
1046 }
1047#endif
1048}
1049
1050static void io_sq_thread_unassociate_blkcg(void)
1051{
1052#ifdef CONFIG_BLK_CGROUP
1053 kthread_associate_blkcg(NULL);
1054#endif
1055}
1056
1057static inline void req_set_fail_links(struct io_kiocb *req)
1058{
1059 if ((req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) == REQ_F_LINK)
1060 req->flags |= REQ_F_FAIL_LINK;
1061}
1062
1063/*
1064 * None of these are dereferenced, they are simply used to check if any of
1065 * them have changed. If we're under current and check they are still the
1066 * same, we're fine to grab references to them for actual out-of-line use.
1067 */
1068static void io_init_identity(struct io_identity *id)
1069{
1070 id->files = current->files;
1071 id->mm = current->mm;
1072#ifdef CONFIG_BLK_CGROUP
1073 rcu_read_lock();
1074 id->blkcg_css = blkcg_css();
1075 rcu_read_unlock();
1076#endif
1077 id->creds = current_cred();
1078 id->nsproxy = current->nsproxy;
1079 id->fs = current->fs;
1080 id->fsize = rlimit(RLIMIT_FSIZE);
1081#ifdef CONFIG_AUDIT
1082 id->loginuid = current->loginuid;
1083 id->sessionid = current->sessionid;
1084#endif
1085 refcount_set(&id->count, 1);
1086}
1087
1088static inline void __io_req_init_async(struct io_kiocb *req)
1089{
1090 memset(&req->work, 0, sizeof(req->work));
1091 req->flags |= REQ_F_WORK_INITIALIZED;
1092}
1093
1094/*
1095 * Note: must call io_req_init_async() for the first time you
1096 * touch any members of io_wq_work.
1097 */
1098static inline void io_req_init_async(struct io_kiocb *req)
1099{
1100 struct io_uring_task *tctx = current->io_uring;
1101
1102 if (req->flags & REQ_F_WORK_INITIALIZED)
1103 return;
1104
1105 __io_req_init_async(req);
1106
1107 /* Grab a ref if this isn't our static identity */
1108 req->work.identity = tctx->identity;
1109 if (tctx->identity != &tctx->__identity)
1110 refcount_inc(&req->work.identity->count);
1111}
1112
1113static inline bool io_async_submit(struct io_ring_ctx *ctx)
1114{
1115 return ctx->flags & IORING_SETUP_SQPOLL;
1116}
1117
1118static void io_ring_ctx_ref_free(struct percpu_ref *ref)
1119{
1120 struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs);
1121
1122 complete(&ctx->ref_comp);
1123}
1124
1125static inline bool io_is_timeout_noseq(struct io_kiocb *req)
1126{
1127 return !req->timeout.off;
1128}
1129
1130static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
1131{
1132 struct io_ring_ctx *ctx;
1133 int hash_bits;
1134
1135 ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
1136 if (!ctx)
1137 return NULL;
1138
1139 ctx->fallback_req = kmem_cache_alloc(req_cachep, GFP_KERNEL);
1140 if (!ctx->fallback_req)
1141 goto err;
1142
1143 /*
1144 * Use 5 bits less than the max cq entries, that should give us around
1145 * 32 entries per hash list if totally full and uniformly spread.
1146 */
1147 hash_bits = ilog2(p->cq_entries);
1148 hash_bits -= 5;
1149 if (hash_bits <= 0)
1150 hash_bits = 1;
1151 ctx->cancel_hash_bits = hash_bits;
1152 ctx->cancel_hash = kmalloc((1U << hash_bits) * sizeof(struct hlist_head),
1153 GFP_KERNEL);
1154 if (!ctx->cancel_hash)
1155 goto err;
1156 __hash_init(ctx->cancel_hash, 1U << hash_bits);
1157
1158 if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free,
1159 PERCPU_REF_ALLOW_REINIT, GFP_KERNEL))
1160 goto err;
1161
1162 ctx->flags = p->flags;
1163 init_waitqueue_head(&ctx->sqo_sq_wait);
1164 INIT_LIST_HEAD(&ctx->sqd_list);
1165 init_waitqueue_head(&ctx->cq_wait);
1166 INIT_LIST_HEAD(&ctx->cq_overflow_list);
1167 init_completion(&ctx->ref_comp);
1168 init_completion(&ctx->sq_thread_comp);
1169 idr_init(&ctx->io_buffer_idr);
1170 idr_init(&ctx->personality_idr);
1171 mutex_init(&ctx->uring_lock);
1172 init_waitqueue_head(&ctx->wait);
1173 spin_lock_init(&ctx->completion_lock);
1174 INIT_LIST_HEAD(&ctx->iopoll_list);
1175 INIT_LIST_HEAD(&ctx->defer_list);
1176 INIT_LIST_HEAD(&ctx->timeout_list);
1177 init_waitqueue_head(&ctx->inflight_wait);
1178 spin_lock_init(&ctx->inflight_lock);
1179 INIT_LIST_HEAD(&ctx->inflight_list);
1180 INIT_DELAYED_WORK(&ctx->file_put_work, io_file_put_work);
1181 init_llist_head(&ctx->file_put_llist);
1182 return ctx;
1183err:
1184 if (ctx->fallback_req)
1185 kmem_cache_free(req_cachep, ctx->fallback_req);
1186 kfree(ctx->cancel_hash);
1187 kfree(ctx);
1188 return NULL;
1189}
1190
1191static bool req_need_defer(struct io_kiocb *req, u32 seq)
1192{
1193 if (unlikely(req->flags & REQ_F_IO_DRAIN)) {
1194 struct io_ring_ctx *ctx = req->ctx;
1195
1196 return seq != ctx->cached_cq_tail
1197 + READ_ONCE(ctx->cached_cq_overflow);
1198 }
1199
1200 return false;
1201}
1202
1203static void __io_commit_cqring(struct io_ring_ctx *ctx)
1204{
1205 struct io_rings *rings = ctx->rings;
1206
1207 /* order cqe stores with ring update */
1208 smp_store_release(&rings->cq.tail, ctx->cached_cq_tail);
1209
1210 if (wq_has_sleeper(&ctx->cq_wait)) {
1211 wake_up_interruptible(&ctx->cq_wait);
1212 kill_fasync(&ctx->cq_fasync, SIGIO, POLL_IN);
1213 }
1214}
1215
1216static void io_put_identity(struct io_uring_task *tctx, struct io_kiocb *req)
1217{
1218 if (req->work.identity == &tctx->__identity)
1219 return;
1220 if (refcount_dec_and_test(&req->work.identity->count))
1221 kfree(req->work.identity);
1222}
1223
1224static void io_req_clean_work(struct io_kiocb *req)
1225{
1226 if (!(req->flags & REQ_F_WORK_INITIALIZED))
1227 return;
1228
1229 req->flags &= ~REQ_F_WORK_INITIALIZED;
1230
1231 if (req->work.flags & IO_WQ_WORK_MM) {
1232 mmdrop(req->work.identity->mm);
1233 req->work.flags &= ~IO_WQ_WORK_MM;
1234 }
1235#ifdef CONFIG_BLK_CGROUP
1236 if (req->work.flags & IO_WQ_WORK_BLKCG) {
1237 css_put(req->work.identity->blkcg_css);
1238 req->work.flags &= ~IO_WQ_WORK_BLKCG;
1239 }
1240#endif
1241 if (req->work.flags & IO_WQ_WORK_CREDS) {
1242 put_cred(req->work.identity->creds);
1243 req->work.flags &= ~IO_WQ_WORK_CREDS;
1244 }
1245 if (req->work.flags & IO_WQ_WORK_FS) {
1246 struct fs_struct *fs = req->work.identity->fs;
1247
1248 spin_lock(&req->work.identity->fs->lock);
1249 if (--fs->users)
1250 fs = NULL;
1251 spin_unlock(&req->work.identity->fs->lock);
1252 if (fs)
1253 free_fs_struct(fs);
1254 req->work.flags &= ~IO_WQ_WORK_FS;
1255 }
1256
1257 io_put_identity(req->task->io_uring, req);
1258}
1259
1260/*
1261 * Create a private copy of io_identity, since some fields don't match
1262 * the current context.
1263 */
1264static bool io_identity_cow(struct io_kiocb *req)
1265{
1266 struct io_uring_task *tctx = current->io_uring;
1267 const struct cred *creds = NULL;
1268 struct io_identity *id;
1269
1270 if (req->work.flags & IO_WQ_WORK_CREDS)
1271 creds = req->work.identity->creds;
1272
1273 id = kmemdup(req->work.identity, sizeof(*id), GFP_KERNEL);
1274 if (unlikely(!id)) {
1275 req->work.flags |= IO_WQ_WORK_CANCEL;
1276 return false;
1277 }
1278
1279 /*
1280 * We can safely just re-init the creds we copied Either the field
1281 * matches the current one, or we haven't grabbed it yet. The only
1282 * exception is ->creds, through registered personalities, so handle
1283 * that one separately.
1284 */
1285 io_init_identity(id);
1286 if (creds)
1287 req->work.identity->creds = creds;
1288
1289 /* add one for this request */
1290 refcount_inc(&id->count);
1291
1292 /* drop tctx and req identity references, if needed */
1293 if (tctx->identity != &tctx->__identity &&
1294 refcount_dec_and_test(&tctx->identity->count))
1295 kfree(tctx->identity);
1296 if (req->work.identity != &tctx->__identity &&
1297 refcount_dec_and_test(&req->work.identity->count))
1298 kfree(req->work.identity);
1299
1300 req->work.identity = id;
1301 tctx->identity = id;
1302 return true;
1303}
1304
1305static bool io_grab_identity(struct io_kiocb *req)
1306{
1307 const struct io_op_def *def = &io_op_defs[req->opcode];
1308 struct io_identity *id = req->work.identity;
1309 struct io_ring_ctx *ctx = req->ctx;
1310
1311 if (def->work_flags & IO_WQ_WORK_FSIZE) {
1312 if (id->fsize != rlimit(RLIMIT_FSIZE))
1313 return false;
1314 req->work.flags |= IO_WQ_WORK_FSIZE;
1315 }
1316#ifdef CONFIG_BLK_CGROUP
1317 if (!(req->work.flags & IO_WQ_WORK_BLKCG) &&
1318 (def->work_flags & IO_WQ_WORK_BLKCG)) {
1319 rcu_read_lock();
1320 if (id->blkcg_css != blkcg_css()) {
1321 rcu_read_unlock();
1322 return false;
1323 }
1324 /*
1325 * This should be rare, either the cgroup is dying or the task
1326 * is moving cgroups. Just punt to root for the handful of ios.
1327 */
1328 if (css_tryget_online(id->blkcg_css))
1329 req->work.flags |= IO_WQ_WORK_BLKCG;
1330 rcu_read_unlock();
1331 }
1332#endif
1333 if (!(req->work.flags & IO_WQ_WORK_CREDS)) {
1334 if (id->creds != current_cred())
1335 return false;
1336 get_cred(id->creds);
1337 req->work.flags |= IO_WQ_WORK_CREDS;
1338 }
1339#ifdef CONFIG_AUDIT
1340 if (!uid_eq(current->loginuid, id->loginuid) ||
1341 current->sessionid != id->sessionid)
1342 return false;
1343#endif
1344 if (!(req->work.flags & IO_WQ_WORK_FS) &&
1345 (def->work_flags & IO_WQ_WORK_FS)) {
1346 if (current->fs != id->fs)
1347 return false;
1348 spin_lock(&id->fs->lock);
1349 if (!id->fs->in_exec) {
1350 id->fs->users++;
1351 req->work.flags |= IO_WQ_WORK_FS;
1352 } else {
1353 req->work.flags |= IO_WQ_WORK_CANCEL;
1354 }
1355 spin_unlock(&current->fs->lock);
1356 }
1357 if (!(req->work.flags & IO_WQ_WORK_FILES) &&
1358 (def->work_flags & IO_WQ_WORK_FILES) &&
1359 !(req->flags & REQ_F_NO_FILE_TABLE)) {
1360 if (id->files != current->files ||
1361 id->nsproxy != current->nsproxy)
1362 return false;
1363 atomic_inc(&id->files->count);
1364 get_nsproxy(id->nsproxy);
1365 req->flags |= REQ_F_INFLIGHT;
1366
1367 spin_lock_irq(&ctx->inflight_lock);
1368 list_add(&req->inflight_entry, &ctx->inflight_list);
1369 spin_unlock_irq(&ctx->inflight_lock);
1370 req->work.flags |= IO_WQ_WORK_FILES;
1371 }
1372
1373 return true;
1374}
1375
1376static void io_prep_async_work(struct io_kiocb *req)
1377{
1378 const struct io_op_def *def = &io_op_defs[req->opcode];
1379 struct io_ring_ctx *ctx = req->ctx;
1380 struct io_identity *id;
1381
1382 io_req_init_async(req);
1383 id = req->work.identity;
1384
1385 if (req->flags & REQ_F_FORCE_ASYNC)
1386 req->work.flags |= IO_WQ_WORK_CONCURRENT;
1387
1388 if (req->flags & REQ_F_ISREG) {
1389 if (def->hash_reg_file || (ctx->flags & IORING_SETUP_IOPOLL))
1390 io_wq_hash_work(&req->work, file_inode(req->file));
1391 } else {
1392 if (def->unbound_nonreg_file)
1393 req->work.flags |= IO_WQ_WORK_UNBOUND;
1394 }
1395
1396 /* ->mm can never change on us */
1397 if (!(req->work.flags & IO_WQ_WORK_MM) &&
1398 (def->work_flags & IO_WQ_WORK_MM)) {
1399 mmgrab(id->mm);
1400 req->work.flags |= IO_WQ_WORK_MM;
1401 }
1402
1403 /* if we fail grabbing identity, we must COW, regrab, and retry */
1404 if (io_grab_identity(req))
1405 return;
1406
1407 if (!io_identity_cow(req))
1408 return;
1409
1410 /* can't fail at this point */
1411 if (!io_grab_identity(req))
1412 WARN_ON(1);
1413}
1414
1415static void io_prep_async_link(struct io_kiocb *req)
1416{
1417 struct io_kiocb *cur;
1418
1419 io_prep_async_work(req);
1420 if (req->flags & REQ_F_LINK_HEAD)
1421 list_for_each_entry(cur, &req->link_list, link_list)
1422 io_prep_async_work(cur);
1423}
1424
1425static struct io_kiocb *__io_queue_async_work(struct io_kiocb *req)
1426{
1427 struct io_ring_ctx *ctx = req->ctx;
1428 struct io_kiocb *link = io_prep_linked_timeout(req);
1429
1430 trace_io_uring_queue_async_work(ctx, io_wq_is_hashed(&req->work), req,
1431 &req->work, req->flags);
1432 io_wq_enqueue(ctx->io_wq, &req->work);
1433 return link;
1434}
1435
1436static void io_queue_async_work(struct io_kiocb *req)
1437{
1438 struct io_kiocb *link;
1439
1440 /* init ->work of the whole link before punting */
1441 io_prep_async_link(req);
1442 link = __io_queue_async_work(req);
1443
1444 if (link)
1445 io_queue_linked_timeout(link);
1446}
1447
1448static void io_kill_timeout(struct io_kiocb *req)
1449{
1450 struct io_timeout_data *io = req->async_data;
1451 int ret;
1452
1453 ret = hrtimer_try_to_cancel(&io->timer);
1454 if (ret != -1) {
1455 atomic_set(&req->ctx->cq_timeouts,
1456 atomic_read(&req->ctx->cq_timeouts) + 1);
1457 list_del_init(&req->timeout.list);
1458 io_cqring_fill_event(req, 0);
1459 io_put_req_deferred(req, 1);
1460 }
1461}
1462
1463static bool io_task_match(struct io_kiocb *req, struct task_struct *tsk)
1464{
1465 struct io_ring_ctx *ctx = req->ctx;
1466
1467 if (!tsk || req->task == tsk)
1468 return true;
1469 if (ctx->flags & IORING_SETUP_SQPOLL) {
1470 if (ctx->sq_data && req->task == ctx->sq_data->thread)
1471 return true;
1472 }
1473 return false;
1474}
1475
1476/*
1477 * Returns true if we found and killed one or more timeouts
1478 */
1479static bool io_kill_timeouts(struct io_ring_ctx *ctx, struct task_struct *tsk)
1480{
1481 struct io_kiocb *req, *tmp;
1482 int canceled = 0;
1483
1484 spin_lock_irq(&ctx->completion_lock);
1485 list_for_each_entry_safe(req, tmp, &ctx->timeout_list, timeout.list) {
1486 if (io_task_match(req, tsk)) {
1487 io_kill_timeout(req);
1488 canceled++;
1489 }
1490 }
1491 spin_unlock_irq(&ctx->completion_lock);
1492 return canceled != 0;
1493}
1494
1495static void __io_queue_deferred(struct io_ring_ctx *ctx)
1496{
1497 do {
1498 struct io_defer_entry *de = list_first_entry(&ctx->defer_list,
1499 struct io_defer_entry, list);
1500 struct io_kiocb *link;
1501
1502 if (req_need_defer(de->req, de->seq))
1503 break;
1504 list_del_init(&de->list);
1505 /* punt-init is done before queueing for defer */
1506 link = __io_queue_async_work(de->req);
1507 if (link) {
1508 __io_queue_linked_timeout(link);
1509 /* drop submission reference */
1510 io_put_req_deferred(link, 1);
1511 }
1512 kfree(de);
1513 } while (!list_empty(&ctx->defer_list));
1514}
1515
1516static void io_flush_timeouts(struct io_ring_ctx *ctx)
1517{
1518 while (!list_empty(&ctx->timeout_list)) {
1519 struct io_kiocb *req = list_first_entry(&ctx->timeout_list,
1520 struct io_kiocb, timeout.list);
1521
1522 if (io_is_timeout_noseq(req))
1523 break;
1524 if (req->timeout.target_seq != ctx->cached_cq_tail
1525 - atomic_read(&ctx->cq_timeouts))
1526 break;
1527
1528 list_del_init(&req->timeout.list);
1529 io_kill_timeout(req);
1530 }
1531}
1532
1533static void io_commit_cqring(struct io_ring_ctx *ctx)
1534{
1535 io_flush_timeouts(ctx);
1536 __io_commit_cqring(ctx);
1537
1538 if (unlikely(!list_empty(&ctx->defer_list)))
1539 __io_queue_deferred(ctx);
1540}
1541
1542static inline bool io_sqring_full(struct io_ring_ctx *ctx)
1543{
1544 struct io_rings *r = ctx->rings;
1545
1546 return READ_ONCE(r->sq.tail) - ctx->cached_sq_head == r->sq_ring_entries;
1547}
1548
1549static struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx)
1550{
1551 struct io_rings *rings = ctx->rings;
1552 unsigned tail;
1553
1554 tail = ctx->cached_cq_tail;
1555 /*
1556 * writes to the cq entry need to come after reading head; the
1557 * control dependency is enough as we're using WRITE_ONCE to
1558 * fill the cq entry
1559 */
1560 if (tail - READ_ONCE(rings->cq.head) == rings->cq_ring_entries)
1561 return NULL;
1562
1563 ctx->cached_cq_tail++;
1564 return &rings->cqes[tail & ctx->cq_mask];
1565}
1566
1567static inline bool io_should_trigger_evfd(struct io_ring_ctx *ctx)
1568{
1569 if (!ctx->cq_ev_fd)
1570 return false;
1571 if (READ_ONCE(ctx->rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED)
1572 return false;
1573 if (!ctx->eventfd_async)
1574 return true;
1575 return io_wq_current_is_worker();
1576}
1577
1578static void io_cqring_ev_posted(struct io_ring_ctx *ctx)
1579{
1580 if (waitqueue_active(&ctx->wait))
1581 wake_up(&ctx->wait);
1582 if (ctx->sq_data && waitqueue_active(&ctx->sq_data->wait))
1583 wake_up(&ctx->sq_data->wait);
1584 if (io_should_trigger_evfd(ctx))
1585 eventfd_signal(ctx->cq_ev_fd, 1);
1586}
1587
1588static void io_cqring_mark_overflow(struct io_ring_ctx *ctx)
1589{
1590 if (list_empty(&ctx->cq_overflow_list)) {
1591 clear_bit(0, &ctx->sq_check_overflow);
1592 clear_bit(0, &ctx->cq_check_overflow);
1593 ctx->rings->sq_flags &= ~IORING_SQ_CQ_OVERFLOW;
1594 }
1595}
1596
1597static inline bool __io_match_files(struct io_kiocb *req,
1598 struct files_struct *files)
1599{
1600 return ((req->flags & REQ_F_WORK_INITIALIZED) &&
1601 (req->work.flags & IO_WQ_WORK_FILES)) &&
1602 req->work.identity->files == files;
1603}
1604
1605static bool io_match_files(struct io_kiocb *req,
1606 struct files_struct *files)
1607{
1608 struct io_kiocb *link;
1609
1610 if (!files)
1611 return true;
1612 if (__io_match_files(req, files))
1613 return true;
1614 if (req->flags & REQ_F_LINK_HEAD) {
1615 list_for_each_entry(link, &req->link_list, link_list) {
1616 if (__io_match_files(link, files))
1617 return true;
1618 }
1619 }
1620 return false;
1621}
1622
1623/* Returns true if there are no backlogged entries after the flush */
1624static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force,
1625 struct task_struct *tsk,
1626 struct files_struct *files)
1627{
1628 struct io_rings *rings = ctx->rings;
1629 struct io_kiocb *req, *tmp;
1630 struct io_uring_cqe *cqe;
1631 unsigned long flags;
1632 LIST_HEAD(list);
1633
1634 if (!force) {
1635 if (list_empty_careful(&ctx->cq_overflow_list))
1636 return true;
1637 if ((ctx->cached_cq_tail - READ_ONCE(rings->cq.head) ==
1638 rings->cq_ring_entries))
1639 return false;
1640 }
1641
1642 spin_lock_irqsave(&ctx->completion_lock, flags);
1643
1644 /* if force is set, the ring is going away. always drop after that */
1645 if (force)
1646 ctx->cq_overflow_flushed = 1;
1647
1648 cqe = NULL;
1649 list_for_each_entry_safe(req, tmp, &ctx->cq_overflow_list, compl.list) {
1650 if (tsk && req->task != tsk)
1651 continue;
1652 if (!io_match_files(req, files))
1653 continue;
1654
1655 cqe = io_get_cqring(ctx);
1656 if (!cqe && !force)
1657 break;
1658
1659 list_move(&req->compl.list, &list);
1660 if (cqe) {
1661 WRITE_ONCE(cqe->user_data, req->user_data);
1662 WRITE_ONCE(cqe->res, req->result);
1663 WRITE_ONCE(cqe->flags, req->compl.cflags);
1664 } else {
1665 ctx->cached_cq_overflow++;
1666 WRITE_ONCE(ctx->rings->cq_overflow,
1667 ctx->cached_cq_overflow);
1668 }
1669 }
1670
1671 io_commit_cqring(ctx);
1672 io_cqring_mark_overflow(ctx);
1673
1674 spin_unlock_irqrestore(&ctx->completion_lock, flags);
1675 io_cqring_ev_posted(ctx);
1676
1677 while (!list_empty(&list)) {
1678 req = list_first_entry(&list, struct io_kiocb, compl.list);
1679 list_del(&req->compl.list);
1680 io_put_req(req);
1681 }
1682
1683 return cqe != NULL;
1684}
1685
1686static void __io_cqring_fill_event(struct io_kiocb *req, long res, long cflags)
1687{
1688 struct io_ring_ctx *ctx = req->ctx;
1689 struct io_uring_cqe *cqe;
1690
1691 trace_io_uring_complete(ctx, req->user_data, res);
1692
1693 /*
1694 * If we can't get a cq entry, userspace overflowed the
1695 * submission (by quite a lot). Increment the overflow count in
1696 * the ring.
1697 */
1698 cqe = io_get_cqring(ctx);
1699 if (likely(cqe)) {
1700 WRITE_ONCE(cqe->user_data, req->user_data);
1701 WRITE_ONCE(cqe->res, res);
1702 WRITE_ONCE(cqe->flags, cflags);
1703 } else if (ctx->cq_overflow_flushed ||
1704 atomic_read(&req->task->io_uring->in_idle)) {
1705 /*
1706 * If we're in ring overflow flush mode, or in task cancel mode,
1707 * then we cannot store the request for later flushing, we need
1708 * to drop it on the floor.
1709 */
1710 ctx->cached_cq_overflow++;
1711 WRITE_ONCE(ctx->rings->cq_overflow, ctx->cached_cq_overflow);
1712 } else {
1713 if (list_empty(&ctx->cq_overflow_list)) {
1714 set_bit(0, &ctx->sq_check_overflow);
1715 set_bit(0, &ctx->cq_check_overflow);
1716 ctx->rings->sq_flags |= IORING_SQ_CQ_OVERFLOW;
1717 }
1718 io_clean_op(req);
1719 req->result = res;
1720 req->compl.cflags = cflags;
1721 refcount_inc(&req->refs);
1722 list_add_tail(&req->compl.list, &ctx->cq_overflow_list);
1723 }
1724}
1725
1726static void io_cqring_fill_event(struct io_kiocb *req, long res)
1727{
1728 __io_cqring_fill_event(req, res, 0);
1729}
1730
1731static void io_cqring_add_event(struct io_kiocb *req, long res, long cflags)
1732{
1733 struct io_ring_ctx *ctx = req->ctx;
1734 unsigned long flags;
1735
1736 spin_lock_irqsave(&ctx->completion_lock, flags);
1737 __io_cqring_fill_event(req, res, cflags);
1738 io_commit_cqring(ctx);
1739 spin_unlock_irqrestore(&ctx->completion_lock, flags);
1740
1741 io_cqring_ev_posted(ctx);
1742}
1743
1744static void io_submit_flush_completions(struct io_comp_state *cs)
1745{
1746 struct io_ring_ctx *ctx = cs->ctx;
1747
1748 spin_lock_irq(&ctx->completion_lock);
1749 while (!list_empty(&cs->list)) {
1750 struct io_kiocb *req;
1751
1752 req = list_first_entry(&cs->list, struct io_kiocb, compl.list);
1753 list_del(&req->compl.list);
1754 __io_cqring_fill_event(req, req->result, req->compl.cflags);
1755
1756 /*
1757 * io_free_req() doesn't care about completion_lock unless one
1758 * of these flags is set. REQ_F_WORK_INITIALIZED is in the list
1759 * because of a potential deadlock with req->work.fs->lock
1760 */
1761 if (req->flags & (REQ_F_FAIL_LINK|REQ_F_LINK_TIMEOUT
1762 |REQ_F_WORK_INITIALIZED)) {
1763 spin_unlock_irq(&ctx->completion_lock);
1764 io_put_req(req);
1765 spin_lock_irq(&ctx->completion_lock);
1766 } else {
1767 io_put_req(req);
1768 }
1769 }
1770 io_commit_cqring(ctx);
1771 spin_unlock_irq(&ctx->completion_lock);
1772
1773 io_cqring_ev_posted(ctx);
1774 cs->nr = 0;
1775}
1776
1777static void __io_req_complete(struct io_kiocb *req, long res, unsigned cflags,
1778 struct io_comp_state *cs)
1779{
1780 if (!cs) {
1781 io_cqring_add_event(req, res, cflags);
1782 io_put_req(req);
1783 } else {
1784 io_clean_op(req);
1785 req->result = res;
1786 req->compl.cflags = cflags;
1787 list_add_tail(&req->compl.list, &cs->list);
1788 if (++cs->nr >= 32)
1789 io_submit_flush_completions(cs);
1790 }
1791}
1792
1793static void io_req_complete(struct io_kiocb *req, long res)
1794{
1795 __io_req_complete(req, res, 0, NULL);
1796}
1797
1798static inline bool io_is_fallback_req(struct io_kiocb *req)
1799{
1800 return req == (struct io_kiocb *)
1801 ((unsigned long) req->ctx->fallback_req & ~1UL);
1802}
1803
1804static struct io_kiocb *io_get_fallback_req(struct io_ring_ctx *ctx)
1805{
1806 struct io_kiocb *req;
1807
1808 req = ctx->fallback_req;
1809 if (!test_and_set_bit_lock(0, (unsigned long *) &ctx->fallback_req))
1810 return req;
1811
1812 return NULL;
1813}
1814
1815static struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx,
1816 struct io_submit_state *state)
1817{
1818 if (!state->free_reqs) {
1819 gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
1820 size_t sz;
1821 int ret;
1822
1823 sz = min_t(size_t, state->ios_left, ARRAY_SIZE(state->reqs));
1824 ret = kmem_cache_alloc_bulk(req_cachep, gfp, sz, state->reqs);
1825
1826 /*
1827 * Bulk alloc is all-or-nothing. If we fail to get a batch,
1828 * retry single alloc to be on the safe side.
1829 */
1830 if (unlikely(ret <= 0)) {
1831 state->reqs[0] = kmem_cache_alloc(req_cachep, gfp);
1832 if (!state->reqs[0])
1833 goto fallback;
1834 ret = 1;
1835 }
1836 state->free_reqs = ret;
1837 }
1838
1839 state->free_reqs--;
1840 return state->reqs[state->free_reqs];
1841fallback:
1842 return io_get_fallback_req(ctx);
1843}
1844
1845static inline void io_put_file(struct io_kiocb *req, struct file *file,
1846 bool fixed)
1847{
1848 if (fixed)
1849 percpu_ref_put(req->fixed_file_refs);
1850 else
1851 fput(file);
1852}
1853
1854static void io_dismantle_req(struct io_kiocb *req)
1855{
1856 io_clean_op(req);
1857
1858 if (req->async_data)
1859 kfree(req->async_data);
1860 if (req->file)
1861 io_put_file(req, req->file, (req->flags & REQ_F_FIXED_FILE));
1862
1863 io_req_clean_work(req);
1864}
1865
1866static void __io_free_req(struct io_kiocb *req)
1867{
1868 struct io_uring_task *tctx = req->task->io_uring;
1869 struct io_ring_ctx *ctx = req->ctx;
1870
1871 io_dismantle_req(req);
1872
1873 percpu_counter_dec(&tctx->inflight);
1874 if (atomic_read(&tctx->in_idle))
1875 wake_up(&tctx->wait);
1876 put_task_struct(req->task);
1877
1878 if (likely(!io_is_fallback_req(req)))
1879 kmem_cache_free(req_cachep, req);
1880 else
1881 clear_bit_unlock(0, (unsigned long *) &ctx->fallback_req);
1882 percpu_ref_put(&ctx->refs);
1883}
1884
1885static void io_kill_linked_timeout(struct io_kiocb *req)
1886{
1887 struct io_ring_ctx *ctx = req->ctx;
1888 struct io_kiocb *link;
1889 bool cancelled = false;
1890 unsigned long flags;
1891
1892 spin_lock_irqsave(&ctx->completion_lock, flags);
1893 link = list_first_entry_or_null(&req->link_list, struct io_kiocb,
1894 link_list);
1895 /*
1896 * Can happen if a linked timeout fired and link had been like
1897 * req -> link t-out -> link t-out [-> ...]
1898 */
1899 if (link && (link->flags & REQ_F_LTIMEOUT_ACTIVE)) {
1900 struct io_timeout_data *io = link->async_data;
1901 int ret;
1902
1903 list_del_init(&link->link_list);
1904 ret = hrtimer_try_to_cancel(&io->timer);
1905 if (ret != -1) {
1906 io_cqring_fill_event(link, -ECANCELED);
1907 io_commit_cqring(ctx);
1908 cancelled = true;
1909 }
1910 }
1911 req->flags &= ~REQ_F_LINK_TIMEOUT;
1912 spin_unlock_irqrestore(&ctx->completion_lock, flags);
1913
1914 if (cancelled) {
1915 io_cqring_ev_posted(ctx);
1916 io_put_req(link);
1917 }
1918}
1919
1920static struct io_kiocb *io_req_link_next(struct io_kiocb *req)
1921{
1922 struct io_kiocb *nxt;
1923
1924 /*
1925 * The list should never be empty when we are called here. But could
1926 * potentially happen if the chain is messed up, check to be on the
1927 * safe side.
1928 */
1929 if (unlikely(list_empty(&req->link_list)))
1930 return NULL;
1931
1932 nxt = list_first_entry(&req->link_list, struct io_kiocb, link_list);
1933 list_del_init(&req->link_list);
1934 if (!list_empty(&nxt->link_list))
1935 nxt->flags |= REQ_F_LINK_HEAD;
1936 return nxt;
1937}
1938
1939/*
1940 * Called if REQ_F_LINK_HEAD is set, and we fail the head request
1941 */
1942static void io_fail_links(struct io_kiocb *req)
1943{
1944 struct io_ring_ctx *ctx = req->ctx;
1945 unsigned long flags;
1946
1947 spin_lock_irqsave(&ctx->completion_lock, flags);
1948 while (!list_empty(&req->link_list)) {
1949 struct io_kiocb *link = list_first_entry(&req->link_list,
1950 struct io_kiocb, link_list);
1951
1952 list_del_init(&link->link_list);
1953 trace_io_uring_fail_link(req, link);
1954
1955 io_cqring_fill_event(link, -ECANCELED);
1956
1957 /*
1958 * It's ok to free under spinlock as they're not linked anymore,
1959 * but avoid REQ_F_WORK_INITIALIZED because it may deadlock on
1960 * work.fs->lock.
1961 */
1962 if (link->flags & REQ_F_WORK_INITIALIZED)
1963 io_put_req_deferred(link, 2);
1964 else
1965 io_double_put_req(link);
1966 }
1967
1968 io_commit_cqring(ctx);
1969 spin_unlock_irqrestore(&ctx->completion_lock, flags);
1970
1971 io_cqring_ev_posted(ctx);
1972}
1973
1974static struct io_kiocb *__io_req_find_next(struct io_kiocb *req)
1975{
1976 req->flags &= ~REQ_F_LINK_HEAD;
1977 if (req->flags & REQ_F_LINK_TIMEOUT)
1978 io_kill_linked_timeout(req);
1979
1980 /*
1981 * If LINK is set, we have dependent requests in this chain. If we
1982 * didn't fail this request, queue the first one up, moving any other
1983 * dependencies to the next request. In case of failure, fail the rest
1984 * of the chain.
1985 */
1986 if (likely(!(req->flags & REQ_F_FAIL_LINK)))
1987 return io_req_link_next(req);
1988 io_fail_links(req);
1989 return NULL;
1990}
1991
1992static struct io_kiocb *io_req_find_next(struct io_kiocb *req)
1993{
1994 if (likely(!(req->flags & REQ_F_LINK_HEAD)))
1995 return NULL;
1996 return __io_req_find_next(req);
1997}
1998
1999static int io_req_task_work_add(struct io_kiocb *req, bool twa_signal_ok)
2000{
2001 struct task_struct *tsk = req->task;
2002 struct io_ring_ctx *ctx = req->ctx;
2003 enum task_work_notify_mode notify;
2004 int ret;
2005
2006 if (tsk->flags & PF_EXITING)
2007 return -ESRCH;
2008
2009 /*
2010 * SQPOLL kernel thread doesn't need notification, just a wakeup. For
2011 * all other cases, use TWA_SIGNAL unconditionally to ensure we're
2012 * processing task_work. There's no reliable way to tell if TWA_RESUME
2013 * will do the job.
2014 */
2015 notify = TWA_NONE;
2016 if (!(ctx->flags & IORING_SETUP_SQPOLL) && twa_signal_ok)
2017 notify = TWA_SIGNAL;
2018
2019 ret = task_work_add(tsk, &req->task_work, notify);
2020 if (!ret)
2021 wake_up_process(tsk);
2022
2023 return ret;
2024}
2025
2026static void __io_req_task_cancel(struct io_kiocb *req, int error)
2027{
2028 struct io_ring_ctx *ctx = req->ctx;
2029
2030 spin_lock_irq(&ctx->completion_lock);
2031 io_cqring_fill_event(req, error);
2032 io_commit_cqring(ctx);
2033 spin_unlock_irq(&ctx->completion_lock);
2034
2035 io_cqring_ev_posted(ctx);
2036 req_set_fail_links(req);
2037 io_double_put_req(req);
2038}
2039
2040static void io_req_task_cancel(struct callback_head *cb)
2041{
2042 struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
2043 struct io_ring_ctx *ctx = req->ctx;
2044
2045 __io_req_task_cancel(req, -ECANCELED);
2046 percpu_ref_put(&ctx->refs);
2047}
2048
2049static void __io_req_task_submit(struct io_kiocb *req)
2050{
2051 struct io_ring_ctx *ctx = req->ctx;
2052
2053 if (!__io_sq_thread_acquire_mm(ctx)) {
2054 mutex_lock(&ctx->uring_lock);
2055 __io_queue_sqe(req, NULL);
2056 mutex_unlock(&ctx->uring_lock);
2057 } else {
2058 __io_req_task_cancel(req, -EFAULT);
2059 }
2060}
2061
2062static void io_req_task_submit(struct callback_head *cb)
2063{
2064 struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
2065 struct io_ring_ctx *ctx = req->ctx;
2066
2067 __io_req_task_submit(req);
2068 percpu_ref_put(&ctx->refs);
2069}
2070
2071static void io_req_task_queue(struct io_kiocb *req)
2072{
2073 int ret;
2074
2075 init_task_work(&req->task_work, io_req_task_submit);
2076 percpu_ref_get(&req->ctx->refs);
2077
2078 ret = io_req_task_work_add(req, true);
2079 if (unlikely(ret)) {
2080 struct task_struct *tsk;
2081
2082 init_task_work(&req->task_work, io_req_task_cancel);
2083 tsk = io_wq_get_task(req->ctx->io_wq);
2084 task_work_add(tsk, &req->task_work, TWA_NONE);
2085 wake_up_process(tsk);
2086 }
2087}
2088
2089static void io_queue_next(struct io_kiocb *req)
2090{
2091 struct io_kiocb *nxt = io_req_find_next(req);
2092
2093 if (nxt)
2094 io_req_task_queue(nxt);
2095}
2096
2097static void io_free_req(struct io_kiocb *req)
2098{
2099 io_queue_next(req);
2100 __io_free_req(req);
2101}
2102
2103struct req_batch {
2104 void *reqs[IO_IOPOLL_BATCH];
2105 int to_free;
2106
2107 struct task_struct *task;
2108 int task_refs;
2109};
2110
2111static inline void io_init_req_batch(struct req_batch *rb)
2112{
2113 rb->to_free = 0;
2114 rb->task_refs = 0;
2115 rb->task = NULL;
2116}
2117
2118static void __io_req_free_batch_flush(struct io_ring_ctx *ctx,
2119 struct req_batch *rb)
2120{
2121 kmem_cache_free_bulk(req_cachep, rb->to_free, rb->reqs);
2122 percpu_ref_put_many(&ctx->refs, rb->to_free);
2123 rb->to_free = 0;
2124}
2125
2126static void io_req_free_batch_finish(struct io_ring_ctx *ctx,
2127 struct req_batch *rb)
2128{
2129 if (rb->to_free)
2130 __io_req_free_batch_flush(ctx, rb);
2131 if (rb->task) {
2132 struct io_uring_task *tctx = rb->task->io_uring;
2133
2134 percpu_counter_sub(&tctx->inflight, rb->task_refs);
2135 put_task_struct_many(rb->task, rb->task_refs);
2136 rb->task = NULL;
2137 }
2138}
2139
2140static void io_req_free_batch(struct req_batch *rb, struct io_kiocb *req)
2141{
2142 if (unlikely(io_is_fallback_req(req))) {
2143 io_free_req(req);
2144 return;
2145 }
2146 if (req->flags & REQ_F_LINK_HEAD)
2147 io_queue_next(req);
2148
2149 if (req->task != rb->task) {
2150 if (rb->task) {
2151 struct io_uring_task *tctx = rb->task->io_uring;
2152
2153 percpu_counter_sub(&tctx->inflight, rb->task_refs);
2154 put_task_struct_many(rb->task, rb->task_refs);
2155 }
2156 rb->task = req->task;
2157 rb->task_refs = 0;
2158 }
2159 rb->task_refs++;
2160
2161 io_dismantle_req(req);
2162 rb->reqs[rb->to_free++] = req;
2163 if (unlikely(rb->to_free == ARRAY_SIZE(rb->reqs)))
2164 __io_req_free_batch_flush(req->ctx, rb);
2165}
2166
2167/*
2168 * Drop reference to request, return next in chain (if there is one) if this
2169 * was the last reference to this request.
2170 */
2171static struct io_kiocb *io_put_req_find_next(struct io_kiocb *req)
2172{
2173 struct io_kiocb *nxt = NULL;
2174
2175 if (refcount_dec_and_test(&req->refs)) {
2176 nxt = io_req_find_next(req);
2177 __io_free_req(req);
2178 }
2179 return nxt;
2180}
2181
2182static void io_put_req(struct io_kiocb *req)
2183{
2184 if (refcount_dec_and_test(&req->refs))
2185 io_free_req(req);
2186}
2187
2188static void io_put_req_deferred_cb(struct callback_head *cb)
2189{
2190 struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
2191
2192 io_free_req(req);
2193}
2194
2195static void io_free_req_deferred(struct io_kiocb *req)
2196{
2197 int ret;
2198
2199 init_task_work(&req->task_work, io_put_req_deferred_cb);
2200 ret = io_req_task_work_add(req, true);
2201 if (unlikely(ret)) {
2202 struct task_struct *tsk;
2203
2204 tsk = io_wq_get_task(req->ctx->io_wq);
2205 task_work_add(tsk, &req->task_work, TWA_NONE);
2206 wake_up_process(tsk);
2207 }
2208}
2209
2210static inline void io_put_req_deferred(struct io_kiocb *req, int refs)
2211{
2212 if (refcount_sub_and_test(refs, &req->refs))
2213 io_free_req_deferred(req);
2214}
2215
2216static struct io_wq_work *io_steal_work(struct io_kiocb *req)
2217{
2218 struct io_kiocb *nxt;
2219
2220 /*
2221 * A ref is owned by io-wq in which context we're. So, if that's the
2222 * last one, it's safe to steal next work. False negatives are Ok,
2223 * it just will be re-punted async in io_put_work()
2224 */
2225 if (refcount_read(&req->refs) != 1)
2226 return NULL;
2227
2228 nxt = io_req_find_next(req);
2229 return nxt ? &nxt->work : NULL;
2230}
2231
2232static void io_double_put_req(struct io_kiocb *req)
2233{
2234 /* drop both submit and complete references */
2235 if (refcount_sub_and_test(2, &req->refs))
2236 io_free_req(req);
2237}
2238
2239static unsigned io_cqring_events(struct io_ring_ctx *ctx, bool noflush)
2240{
2241 struct io_rings *rings = ctx->rings;
2242
2243 if (test_bit(0, &ctx->cq_check_overflow)) {
2244 /*
2245 * noflush == true is from the waitqueue handler, just ensure
2246 * we wake up the task, and the next invocation will flush the
2247 * entries. We cannot safely to it from here.
2248 */
2249 if (noflush && !list_empty(&ctx->cq_overflow_list))
2250 return -1U;
2251
2252 io_cqring_overflow_flush(ctx, false, NULL, NULL);
2253 }
2254
2255 /* See comment at the top of this file */
2256 smp_rmb();
2257 return ctx->cached_cq_tail - READ_ONCE(rings->cq.head);
2258}
2259
2260static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
2261{
2262 struct io_rings *rings = ctx->rings;
2263
2264 /* make sure SQ entry isn't read before tail */
2265 return smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head;
2266}
2267
2268static unsigned int io_put_kbuf(struct io_kiocb *req, struct io_buffer *kbuf)
2269{
2270 unsigned int cflags;
2271
2272 cflags = kbuf->bid << IORING_CQE_BUFFER_SHIFT;
2273 cflags |= IORING_CQE_F_BUFFER;
2274 req->flags &= ~REQ_F_BUFFER_SELECTED;
2275 kfree(kbuf);
2276 return cflags;
2277}
2278
2279static inline unsigned int io_put_rw_kbuf(struct io_kiocb *req)
2280{
2281 struct io_buffer *kbuf;
2282
2283 kbuf = (struct io_buffer *) (unsigned long) req->rw.addr;
2284 return io_put_kbuf(req, kbuf);
2285}
2286
2287static inline bool io_run_task_work(void)
2288{
2289 /*
2290 * Not safe to run on exiting task, and the task_work handling will
2291 * not add work to such a task.
2292 */
2293 if (unlikely(current->flags & PF_EXITING))
2294 return false;
2295 if (current->task_works) {
2296 __set_current_state(TASK_RUNNING);
2297 task_work_run();
2298 return true;
2299 }
2300
2301 return false;
2302}
2303
2304static void io_iopoll_queue(struct list_head *again)
2305{
2306 struct io_kiocb *req;
2307
2308 do {
2309 req = list_first_entry(again, struct io_kiocb, inflight_entry);
2310 list_del(&req->inflight_entry);
2311 __io_complete_rw(req, -EAGAIN, 0, NULL);
2312 } while (!list_empty(again));
2313}
2314
2315/*
2316 * Find and free completed poll iocbs
2317 */
2318static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
2319 struct list_head *done)
2320{
2321 struct req_batch rb;
2322 struct io_kiocb *req;
2323 LIST_HEAD(again);
2324
2325 /* order with ->result store in io_complete_rw_iopoll() */
2326 smp_rmb();
2327
2328 io_init_req_batch(&rb);
2329 while (!list_empty(done)) {
2330 int cflags = 0;
2331
2332 req = list_first_entry(done, struct io_kiocb, inflight_entry);
2333 if (READ_ONCE(req->result) == -EAGAIN) {
2334 req->result = 0;
2335 req->iopoll_completed = 0;
2336 list_move_tail(&req->inflight_entry, &again);
2337 continue;
2338 }
2339 list_del(&req->inflight_entry);
2340
2341 if (req->flags & REQ_F_BUFFER_SELECTED)
2342 cflags = io_put_rw_kbuf(req);
2343
2344 __io_cqring_fill_event(req, req->result, cflags);
2345 (*nr_events)++;
2346
2347 if (refcount_dec_and_test(&req->refs))
2348 io_req_free_batch(&rb, req);
2349 }
2350
2351 io_commit_cqring(ctx);
2352 if (ctx->flags & IORING_SETUP_SQPOLL)
2353 io_cqring_ev_posted(ctx);
2354 io_req_free_batch_finish(ctx, &rb);
2355
2356 if (!list_empty(&again))
2357 io_iopoll_queue(&again);
2358}
2359
2360static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
2361 long min)
2362{
2363 struct io_kiocb *req, *tmp;
2364 LIST_HEAD(done);
2365 bool spin;
2366 int ret;
2367
2368 /*
2369 * Only spin for completions if we don't have multiple devices hanging
2370 * off our complete list, and we're under the requested amount.
2371 */
2372 spin = !ctx->poll_multi_file && *nr_events < min;
2373
2374 ret = 0;
2375 list_for_each_entry_safe(req, tmp, &ctx->iopoll_list, inflight_entry) {
2376 struct kiocb *kiocb = &req->rw.kiocb;
2377
2378 /*
2379 * Move completed and retryable entries to our local lists.
2380 * If we find a request that requires polling, break out
2381 * and complete those lists first, if we have entries there.
2382 */
2383 if (READ_ONCE(req->iopoll_completed)) {
2384 list_move_tail(&req->inflight_entry, &done);
2385 continue;
2386 }
2387 if (!list_empty(&done))
2388 break;
2389
2390 ret = kiocb->ki_filp->f_op->iopoll(kiocb, spin);
2391 if (ret < 0)
2392 break;
2393
2394 /* iopoll may have completed current req */
2395 if (READ_ONCE(req->iopoll_completed))
2396 list_move_tail(&req->inflight_entry, &done);
2397
2398 if (ret && spin)
2399 spin = false;
2400 ret = 0;
2401 }
2402
2403 if (!list_empty(&done))
2404 io_iopoll_complete(ctx, nr_events, &done);
2405
2406 return ret;
2407}
2408
2409/*
2410 * Poll for a minimum of 'min' events. Note that if min == 0 we consider that a
2411 * non-spinning poll check - we'll still enter the driver poll loop, but only
2412 * as a non-spinning completion check.
2413 */
2414static int io_iopoll_getevents(struct io_ring_ctx *ctx, unsigned int *nr_events,
2415 long min)
2416{
2417 while (!list_empty(&ctx->iopoll_list) && !need_resched()) {
2418 int ret;
2419
2420 ret = io_do_iopoll(ctx, nr_events, min);
2421 if (ret < 0)
2422 return ret;
2423 if (*nr_events >= min)
2424 return 0;
2425 }
2426
2427 return 1;
2428}
2429
2430/*
2431 * We can't just wait for polled events to come to us, we have to actively
2432 * find and complete them.
2433 */
2434static void io_iopoll_try_reap_events(struct io_ring_ctx *ctx)
2435{
2436 if (!(ctx->flags & IORING_SETUP_IOPOLL))
2437 return;
2438
2439 mutex_lock(&ctx->uring_lock);
2440 while (!list_empty(&ctx->iopoll_list)) {
2441 unsigned int nr_events = 0;
2442
2443 io_do_iopoll(ctx, &nr_events, 0);
2444
2445 /* let it sleep and repeat later if can't complete a request */
2446 if (nr_events == 0)
2447 break;
2448 /*
2449 * Ensure we allow local-to-the-cpu processing to take place,
2450 * in this case we need to ensure that we reap all events.
2451 * Also let task_work, etc. to progress by releasing the mutex
2452 */
2453 if (need_resched()) {
2454 mutex_unlock(&ctx->uring_lock);
2455 cond_resched();
2456 mutex_lock(&ctx->uring_lock);
2457 }
2458 }
2459 mutex_unlock(&ctx->uring_lock);
2460}
2461
2462static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
2463{
2464 unsigned int nr_events = 0;
2465 int iters = 0, ret = 0;
2466
2467 /*
2468 * We disallow the app entering submit/complete with polling, but we
2469 * still need to lock the ring to prevent racing with polled issue
2470 * that got punted to a workqueue.
2471 */
2472 mutex_lock(&ctx->uring_lock);
2473 do {
2474 /*
2475 * Don't enter poll loop if we already have events pending.
2476 * If we do, we can potentially be spinning for commands that
2477 * already triggered a CQE (eg in error).
2478 */
2479 if (io_cqring_events(ctx, false))
2480 break;
2481
2482 /*
2483 * If a submit got punted to a workqueue, we can have the
2484 * application entering polling for a command before it gets
2485 * issued. That app will hold the uring_lock for the duration
2486 * of the poll right here, so we need to take a breather every
2487 * now and then to ensure that the issue has a chance to add
2488 * the poll to the issued list. Otherwise we can spin here
2489 * forever, while the workqueue is stuck trying to acquire the
2490 * very same mutex.
2491 */
2492 if (!(++iters & 7)) {
2493 mutex_unlock(&ctx->uring_lock);
2494 io_run_task_work();
2495 mutex_lock(&ctx->uring_lock);
2496 }
2497
2498 ret = io_iopoll_getevents(ctx, &nr_events, min);
2499 if (ret <= 0)
2500 break;
2501 ret = 0;
2502 } while (min && !nr_events && !need_resched());
2503
2504 mutex_unlock(&ctx->uring_lock);
2505 return ret;
2506}
2507
2508static void kiocb_end_write(struct io_kiocb *req)
2509{
2510 /*
2511 * Tell lockdep we inherited freeze protection from submission
2512 * thread.
2513 */
2514 if (req->flags & REQ_F_ISREG) {
2515 struct inode *inode = file_inode(req->file);
2516
2517 __sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
2518 }
2519 file_end_write(req->file);
2520}
2521
2522static void io_complete_rw_common(struct kiocb *kiocb, long res,
2523 struct io_comp_state *cs)
2524{
2525 struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
2526 int cflags = 0;
2527
2528 if (kiocb->ki_flags & IOCB_WRITE)
2529 kiocb_end_write(req);
2530
2531 if (res != req->result)
2532 req_set_fail_links(req);
2533 if (req->flags & REQ_F_BUFFER_SELECTED)
2534 cflags = io_put_rw_kbuf(req);
2535 __io_req_complete(req, res, cflags, cs);
2536}
2537
2538#ifdef CONFIG_BLOCK
2539static bool io_resubmit_prep(struct io_kiocb *req, int error)
2540{
2541 struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
2542 ssize_t ret = -ECANCELED;
2543 struct iov_iter iter;
2544 int rw;
2545
2546 if (error) {
2547 ret = error;
2548 goto end_req;
2549 }
2550
2551 switch (req->opcode) {
2552 case IORING_OP_READV:
2553 case IORING_OP_READ_FIXED:
2554 case IORING_OP_READ:
2555 rw = READ;
2556 break;
2557 case IORING_OP_WRITEV:
2558 case IORING_OP_WRITE_FIXED:
2559 case IORING_OP_WRITE:
2560 rw = WRITE;
2561 break;
2562 default:
2563 printk_once(KERN_WARNING "io_uring: bad opcode in resubmit %d\n",
2564 req->opcode);
2565 goto end_req;
2566 }
2567
2568 if (!req->async_data) {
2569 ret = io_import_iovec(rw, req, &iovec, &iter, false);
2570 if (ret < 0)
2571 goto end_req;
2572 ret = io_setup_async_rw(req, iovec, inline_vecs, &iter, false);
2573 if (!ret)
2574 return true;
2575 kfree(iovec);
2576 } else {
2577 return true;
2578 }
2579end_req:
2580 req_set_fail_links(req);
2581 return false;
2582}
2583#endif
2584
2585static bool io_rw_reissue(struct io_kiocb *req, long res)
2586{
2587#ifdef CONFIG_BLOCK
2588 umode_t mode = file_inode(req->file)->i_mode;
2589 int ret;
2590
2591 if (!S_ISBLK(mode) && !S_ISREG(mode))
2592 return false;
2593 if ((res != -EAGAIN && res != -EOPNOTSUPP) || io_wq_current_is_worker())
2594 return false;
2595
2596 ret = io_sq_thread_acquire_mm(req->ctx, req);
2597
2598 if (io_resubmit_prep(req, ret)) {
2599 refcount_inc(&req->refs);
2600 io_queue_async_work(req);
2601 return true;
2602 }
2603
2604#endif
2605 return false;
2606}
2607
2608static void __io_complete_rw(struct io_kiocb *req, long res, long res2,
2609 struct io_comp_state *cs)
2610{
2611 if (!io_rw_reissue(req, res))
2612 io_complete_rw_common(&req->rw.kiocb, res, cs);
2613}
2614
2615static void io_complete_rw(struct kiocb *kiocb, long res, long res2)
2616{
2617 struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
2618
2619 __io_complete_rw(req, res, res2, NULL);
2620}
2621
2622static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2)
2623{
2624 struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
2625
2626 if (kiocb->ki_flags & IOCB_WRITE)
2627 kiocb_end_write(req);
2628
2629 if (res != -EAGAIN && res != req->result)
2630 req_set_fail_links(req);
2631
2632 WRITE_ONCE(req->result, res);
2633 /* order with io_poll_complete() checking ->result */
2634 smp_wmb();
2635 WRITE_ONCE(req->iopoll_completed, 1);
2636}
2637
2638/*
2639 * After the iocb has been issued, it's safe to be found on the poll list.
2640 * Adding the kiocb to the list AFTER submission ensures that we don't
2641 * find it from a io_iopoll_getevents() thread before the issuer is done
2642 * accessing the kiocb cookie.
2643 */
2644static void io_iopoll_req_issued(struct io_kiocb *req)
2645{
2646 struct io_ring_ctx *ctx = req->ctx;
2647
2648 /*
2649 * Track whether we have multiple files in our lists. This will impact
2650 * how we do polling eventually, not spinning if we're on potentially
2651 * different devices.
2652 */
2653 if (list_empty(&ctx->iopoll_list)) {
2654 ctx->poll_multi_file = false;
2655 } else if (!ctx->poll_multi_file) {
2656 struct io_kiocb *list_req;
2657
2658 list_req = list_first_entry(&ctx->iopoll_list, struct io_kiocb,
2659 inflight_entry);
2660 if (list_req->file != req->file)
2661 ctx->poll_multi_file = true;
2662 }
2663
2664 /*
2665 * For fast devices, IO may have already completed. If it has, add
2666 * it to the front so we find it first.
2667 */
2668 if (READ_ONCE(req->iopoll_completed))
2669 list_add(&req->inflight_entry, &ctx->iopoll_list);
2670 else
2671 list_add_tail(&req->inflight_entry, &ctx->iopoll_list);
2672
2673 if ((ctx->flags & IORING_SETUP_SQPOLL) &&
2674 wq_has_sleeper(&ctx->sq_data->wait))
2675 wake_up(&ctx->sq_data->wait);
2676}
2677
2678static void __io_state_file_put(struct io_submit_state *state)
2679{
2680 if (state->has_refs)
2681 fput_many(state->file, state->has_refs);
2682 state->file = NULL;
2683}
2684
2685static inline void io_state_file_put(struct io_submit_state *state)
2686{
2687 if (state->file)
2688 __io_state_file_put(state);
2689}
2690
2691/*
2692 * Get as many references to a file as we have IOs left in this submission,
2693 * assuming most submissions are for one file, or at least that each file
2694 * has more than one submission.
2695 */
2696static struct file *__io_file_get(struct io_submit_state *state, int fd)
2697{
2698 if (!state)
2699 return fget(fd);
2700
2701 if (state->file) {
2702 if (state->fd == fd) {
2703 state->has_refs--;
2704 return state->file;
2705 }
2706 __io_state_file_put(state);
2707 }
2708 state->file = fget_many(fd, state->ios_left);
2709 if (!state->file)
2710 return NULL;
2711
2712 state->fd = fd;
2713 state->has_refs = state->ios_left - 1;
2714 return state->file;
2715}
2716
2717static bool io_bdev_nowait(struct block_device *bdev)
2718{
2719#ifdef CONFIG_BLOCK
2720 return !bdev || blk_queue_nowait(bdev_get_queue(bdev));
2721#else
2722 return true;
2723#endif
2724}
2725
2726/*
2727 * If we tracked the file through the SCM inflight mechanism, we could support
2728 * any file. For now, just ensure that anything potentially problematic is done
2729 * inline.
2730 */
2731static bool io_file_supports_async(struct file *file, int rw)
2732{
2733 umode_t mode = file_inode(file)->i_mode;
2734
2735 if (S_ISBLK(mode)) {
2736 if (io_bdev_nowait(file->f_inode->i_bdev))
2737 return true;
2738 return false;
2739 }
2740 if (S_ISCHR(mode) || S_ISSOCK(mode))
2741 return true;
2742 if (S_ISREG(mode)) {
2743 if (io_bdev_nowait(file->f_inode->i_sb->s_bdev) &&
2744 file->f_op != &io_uring_fops)
2745 return true;
2746 return false;
2747 }
2748
2749 /* any ->read/write should understand O_NONBLOCK */
2750 if (file->f_flags & O_NONBLOCK)
2751 return true;
2752
2753 if (!(file->f_mode & FMODE_NOWAIT))
2754 return false;
2755
2756 if (rw == READ)
2757 return file->f_op->read_iter != NULL;
2758
2759 return file->f_op->write_iter != NULL;
2760}
2761
2762static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
2763{
2764 struct io_ring_ctx *ctx = req->ctx;
2765 struct kiocb *kiocb = &req->rw.kiocb;
2766 unsigned ioprio;
2767 int ret;
2768
2769 if (S_ISREG(file_inode(req->file)->i_mode))
2770 req->flags |= REQ_F_ISREG;
2771
2772 kiocb->ki_pos = READ_ONCE(sqe->off);
2773 if (kiocb->ki_pos == -1 && !(req->file->f_mode & FMODE_STREAM)) {
2774 req->flags |= REQ_F_CUR_POS;
2775 kiocb->ki_pos = req->file->f_pos;
2776 }
2777 kiocb->ki_hint = ki_hint_validate(file_write_hint(kiocb->ki_filp));
2778 kiocb->ki_flags = iocb_flags(kiocb->ki_filp);
2779 ret = kiocb_set_rw_flags(kiocb, READ_ONCE(sqe->rw_flags));
2780 if (unlikely(ret))
2781 return ret;
2782
2783 ioprio = READ_ONCE(sqe->ioprio);
2784 if (ioprio) {
2785 ret = ioprio_check_cap(ioprio);
2786 if (ret)
2787 return ret;
2788
2789 kiocb->ki_ioprio = ioprio;
2790 } else
2791 kiocb->ki_ioprio = get_current_ioprio();
2792
2793 /* don't allow async punt if RWF_NOWAIT was requested */
2794 if (kiocb->ki_flags & IOCB_NOWAIT)
2795 req->flags |= REQ_F_NOWAIT;
2796
2797 if (ctx->flags & IORING_SETUP_IOPOLL) {
2798 if (!(kiocb->ki_flags & IOCB_DIRECT) ||
2799 !kiocb->ki_filp->f_op->iopoll)
2800 return -EOPNOTSUPP;
2801
2802 kiocb->ki_flags |= IOCB_HIPRI;
2803 kiocb->ki_complete = io_complete_rw_iopoll;
2804 req->iopoll_completed = 0;
2805 } else {
2806 if (kiocb->ki_flags & IOCB_HIPRI)
2807 return -EINVAL;
2808 kiocb->ki_complete = io_complete_rw;
2809 }
2810
2811 req->rw.addr = READ_ONCE(sqe->addr);
2812 req->rw.len = READ_ONCE(sqe->len);
2813 req->buf_index = READ_ONCE(sqe->buf_index);
2814 return 0;
2815}
2816
2817static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
2818{
2819 switch (ret) {
2820 case -EIOCBQUEUED:
2821 break;
2822 case -ERESTARTSYS:
2823 case -ERESTARTNOINTR:
2824 case -ERESTARTNOHAND:
2825 case -ERESTART_RESTARTBLOCK:
2826 /*
2827 * We can't just restart the syscall, since previously
2828 * submitted sqes may already be in progress. Just fail this
2829 * IO with EINTR.
2830 */
2831 ret = -EINTR;
2832 fallthrough;
2833 default:
2834 kiocb->ki_complete(kiocb, ret, 0);
2835 }
2836}
2837
2838static void kiocb_done(struct kiocb *kiocb, ssize_t ret,
2839 struct io_comp_state *cs)
2840{
2841 struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
2842 struct io_async_rw *io = req->async_data;
2843
2844 /* add previously done IO, if any */
2845 if (io && io->bytes_done > 0) {
2846 if (ret < 0)
2847 ret = io->bytes_done;
2848 else
2849 ret += io->bytes_done;
2850 }
2851
2852 if (req->flags & REQ_F_CUR_POS)
2853 req->file->f_pos = kiocb->ki_pos;
2854 if (ret >= 0 && kiocb->ki_complete == io_complete_rw)
2855 __io_complete_rw(req, ret, 0, cs);
2856 else
2857 io_rw_done(kiocb, ret);
2858}
2859
2860static ssize_t io_import_fixed(struct io_kiocb *req, int rw,
2861 struct iov_iter *iter)
2862{
2863 struct io_ring_ctx *ctx = req->ctx;
2864 size_t len = req->rw.len;
2865 struct io_mapped_ubuf *imu;
2866 u16 index, buf_index = req->buf_index;
2867 size_t offset;
2868 u64 buf_addr;
2869
2870 if (unlikely(buf_index >= ctx->nr_user_bufs))
2871 return -EFAULT;
2872 index = array_index_nospec(buf_index, ctx->nr_user_bufs);
2873 imu = &ctx->user_bufs[index];
2874 buf_addr = req->rw.addr;
2875
2876 /* overflow */
2877 if (buf_addr + len < buf_addr)
2878 return -EFAULT;
2879 /* not inside the mapped region */
2880 if (buf_addr < imu->ubuf || buf_addr + len > imu->ubuf + imu->len)
2881 return -EFAULT;
2882
2883 /*
2884 * May not be a start of buffer, set size appropriately
2885 * and advance us to the beginning.
2886 */
2887 offset = buf_addr - imu->ubuf;
2888 iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len);
2889
2890 if (offset) {
2891 /*
2892 * Don't use iov_iter_advance() here, as it's really slow for
2893 * using the latter parts of a big fixed buffer - it iterates
2894 * over each segment manually. We can cheat a bit here, because
2895 * we know that:
2896 *
2897 * 1) it's a BVEC iter, we set it up
2898 * 2) all bvecs are PAGE_SIZE in size, except potentially the
2899 * first and last bvec
2900 *
2901 * So just find our index, and adjust the iterator afterwards.
2902 * If the offset is within the first bvec (or the whole first
2903 * bvec, just use iov_iter_advance(). This makes it easier
2904 * since we can just skip the first segment, which may not
2905 * be PAGE_SIZE aligned.
2906 */
2907 const struct bio_vec *bvec = imu->bvec;
2908
2909 if (offset <= bvec->bv_len) {
2910 iov_iter_advance(iter, offset);
2911 } else {
2912 unsigned long seg_skip;
2913
2914 /* skip first vec */
2915 offset -= bvec->bv_len;
2916 seg_skip = 1 + (offset >> PAGE_SHIFT);
2917
2918 iter->bvec = bvec + seg_skip;
2919 iter->nr_segs -= seg_skip;
2920 iter->count -= bvec->bv_len + offset;
2921 iter->iov_offset = offset & ~PAGE_MASK;
2922 }
2923 }
2924
2925 return len;
2926}
2927
2928static void io_ring_submit_unlock(struct io_ring_ctx *ctx, bool needs_lock)
2929{
2930 if (needs_lock)
2931 mutex_unlock(&ctx->uring_lock);
2932}
2933
2934static void io_ring_submit_lock(struct io_ring_ctx *ctx, bool needs_lock)
2935{
2936 /*
2937 * "Normal" inline submissions always hold the uring_lock, since we
2938 * grab it from the system call. Same is true for the SQPOLL offload.
2939 * The only exception is when we've detached the request and issue it
2940 * from an async worker thread, grab the lock for that case.
2941 */
2942 if (needs_lock)
2943 mutex_lock(&ctx->uring_lock);
2944}
2945
2946static struct io_buffer *io_buffer_select(struct io_kiocb *req, size_t *len,
2947 int bgid, struct io_buffer *kbuf,
2948 bool needs_lock)
2949{
2950 struct io_buffer *head;
2951
2952 if (req->flags & REQ_F_BUFFER_SELECTED)
2953 return kbuf;
2954
2955 io_ring_submit_lock(req->ctx, needs_lock);
2956
2957 lockdep_assert_held(&req->ctx->uring_lock);
2958
2959 head = idr_find(&req->ctx->io_buffer_idr, bgid);
2960 if (head) {
2961 if (!list_empty(&head->list)) {
2962 kbuf = list_last_entry(&head->list, struct io_buffer,
2963 list);
2964 list_del(&kbuf->list);
2965 } else {
2966 kbuf = head;
2967 idr_remove(&req->ctx->io_buffer_idr, bgid);
2968 }
2969 if (*len > kbuf->len)
2970 *len = kbuf->len;
2971 } else {
2972 kbuf = ERR_PTR(-ENOBUFS);
2973 }
2974
2975 io_ring_submit_unlock(req->ctx, needs_lock);
2976
2977 return kbuf;
2978}
2979
2980static void __user *io_rw_buffer_select(struct io_kiocb *req, size_t *len,
2981 bool needs_lock)
2982{
2983 struct io_buffer *kbuf;
2984 u16 bgid;
2985
2986 kbuf = (struct io_buffer *) (unsigned long) req->rw.addr;
2987 bgid = req->buf_index;
2988 kbuf = io_buffer_select(req, len, bgid, kbuf, needs_lock);
2989 if (IS_ERR(kbuf))
2990 return kbuf;
2991 req->rw.addr = (u64) (unsigned long) kbuf;
2992 req->flags |= REQ_F_BUFFER_SELECTED;
2993 return u64_to_user_ptr(kbuf->addr);
2994}
2995
2996#ifdef CONFIG_COMPAT
2997static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov,
2998 bool needs_lock)
2999{
3000 struct compat_iovec __user *uiov;
3001 compat_ssize_t clen;
3002 void __user *buf;
3003 ssize_t len;
3004
3005 uiov = u64_to_user_ptr(req->rw.addr);
3006 if (!access_ok(uiov, sizeof(*uiov)))
3007 return -EFAULT;
3008 if (__get_user(clen, &uiov->iov_len))
3009 return -EFAULT;
3010 if (clen < 0)
3011 return -EINVAL;
3012
3013 len = clen;
3014 buf = io_rw_buffer_select(req, &len, needs_lock);
3015 if (IS_ERR(buf))
3016 return PTR_ERR(buf);
3017 iov[0].iov_base = buf;
3018 iov[0].iov_len = (compat_size_t) len;
3019 return 0;
3020}
3021#endif
3022
3023static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
3024 bool needs_lock)
3025{
3026 struct iovec __user *uiov = u64_to_user_ptr(req->rw.addr);
3027 void __user *buf;
3028 ssize_t len;
3029
3030 if (copy_from_user(iov, uiov, sizeof(*uiov)))
3031 return -EFAULT;
3032
3033 len = iov[0].iov_len;
3034 if (len < 0)
3035 return -EINVAL;
3036 buf = io_rw_buffer_select(req, &len, needs_lock);
3037 if (IS_ERR(buf))
3038 return PTR_ERR(buf);
3039 iov[0].iov_base = buf;
3040 iov[0].iov_len = len;
3041 return 0;
3042}
3043
3044static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
3045 bool needs_lock)
3046{
3047 if (req->flags & REQ_F_BUFFER_SELECTED) {
3048 struct io_buffer *kbuf;
3049
3050 kbuf = (struct io_buffer *) (unsigned long) req->rw.addr;
3051 iov[0].iov_base = u64_to_user_ptr(kbuf->addr);
3052 iov[0].iov_len = kbuf->len;
3053 return 0;
3054 }
3055 if (!req->rw.len)
3056 return 0;
3057 else if (req->rw.len > 1)
3058 return -EINVAL;
3059
3060#ifdef CONFIG_COMPAT
3061 if (req->ctx->compat)
3062 return io_compat_import(req, iov, needs_lock);
3063#endif
3064
3065 return __io_iov_buffer_select(req, iov, needs_lock);
3066}
3067
3068static ssize_t __io_import_iovec(int rw, struct io_kiocb *req,
3069 struct iovec **iovec, struct iov_iter *iter,
3070 bool needs_lock)
3071{
3072 void __user *buf = u64_to_user_ptr(req->rw.addr);
3073 size_t sqe_len = req->rw.len;
3074 ssize_t ret;
3075 u8 opcode;
3076
3077 opcode = req->opcode;
3078 if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
3079 *iovec = NULL;
3080 return io_import_fixed(req, rw, iter);
3081 }
3082
3083 /* buffer index only valid with fixed read/write, or buffer select */
3084 if (req->buf_index && !(req->flags & REQ_F_BUFFER_SELECT))
3085 return -EINVAL;
3086
3087 if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE) {
3088 if (req->flags & REQ_F_BUFFER_SELECT) {
3089 buf = io_rw_buffer_select(req, &sqe_len, needs_lock);
3090 if (IS_ERR(buf))
3091 return PTR_ERR(buf);
3092 req->rw.len = sqe_len;
3093 }
3094
3095 ret = import_single_range(rw, buf, sqe_len, *iovec, iter);
3096 *iovec = NULL;
3097 return ret < 0 ? ret : sqe_len;
3098 }
3099
3100 if (req->flags & REQ_F_BUFFER_SELECT) {
3101 ret = io_iov_buffer_select(req, *iovec, needs_lock);
3102 if (!ret) {
3103 ret = (*iovec)->iov_len;
3104 iov_iter_init(iter, rw, *iovec, 1, ret);
3105 }
3106 *iovec = NULL;
3107 return ret;
3108 }
3109
3110 return __import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter,
3111 req->ctx->compat);
3112}
3113
3114static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
3115 struct iovec **iovec, struct iov_iter *iter,
3116 bool needs_lock)
3117{
3118 struct io_async_rw *iorw = req->async_data;
3119
3120 if (!iorw)
3121 return __io_import_iovec(rw, req, iovec, iter, needs_lock);
3122 *iovec = NULL;
3123 return iov_iter_count(&iorw->iter);
3124}
3125
3126static inline loff_t *io_kiocb_ppos(struct kiocb *kiocb)
3127{
3128 return (kiocb->ki_filp->f_mode & FMODE_STREAM) ? NULL : &kiocb->ki_pos;
3129}
3130
3131/*
3132 * For files that don't have ->read_iter() and ->write_iter(), handle them
3133 * by looping over ->read() or ->write() manually.
3134 */
3135static ssize_t loop_rw_iter(int rw, struct io_kiocb *req, struct iov_iter *iter)
3136{
3137 struct kiocb *kiocb = &req->rw.kiocb;
3138 struct file *file = req->file;
3139 ssize_t ret = 0;
3140
3141 /*
3142 * Don't support polled IO through this interface, and we can't
3143 * support non-blocking either. For the latter, this just causes
3144 * the kiocb to be handled from an async context.
3145 */
3146 if (kiocb->ki_flags & IOCB_HIPRI)
3147 return -EOPNOTSUPP;
3148 if (kiocb->ki_flags & IOCB_NOWAIT)
3149 return -EAGAIN;
3150
3151 while (iov_iter_count(iter)) {
3152 struct iovec iovec;
3153 ssize_t nr;
3154
3155 if (!iov_iter_is_bvec(iter)) {
3156 iovec = iov_iter_iovec(iter);
3157 } else {
3158 iovec.iov_base = u64_to_user_ptr(req->rw.addr);
3159 iovec.iov_len = req->rw.len;
3160 }
3161
3162 if (rw == READ) {
3163 nr = file->f_op->read(file, iovec.iov_base,
3164 iovec.iov_len, io_kiocb_ppos(kiocb));
3165 } else {
3166 nr = file->f_op->write(file, iovec.iov_base,
3167 iovec.iov_len, io_kiocb_ppos(kiocb));
3168 }
3169
3170 if (nr < 0) {
3171 if (!ret)
3172 ret = nr;
3173 break;
3174 }
3175 ret += nr;
3176 if (nr != iovec.iov_len)
3177 break;
3178 req->rw.len -= nr;
3179 req->rw.addr += nr;
3180 iov_iter_advance(iter, nr);
3181 }
3182
3183 return ret;
3184}
3185
3186static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec,
3187 const struct iovec *fast_iov, struct iov_iter *iter)
3188{
3189 struct io_async_rw *rw = req->async_data;
3190
3191 memcpy(&rw->iter, iter, sizeof(*iter));
3192 rw->free_iovec = iovec;
3193 rw->bytes_done = 0;
3194 /* can only be fixed buffers, no need to do anything */
3195 if (iov_iter_is_bvec(iter))
3196 return;
3197 if (!iovec) {
3198 unsigned iov_off = 0;
3199
3200 rw->iter.iov = rw->fast_iov;
3201 if (iter->iov != fast_iov) {
3202 iov_off = iter->iov - fast_iov;
3203 rw->iter.iov += iov_off;
3204 }
3205 if (rw->fast_iov != fast_iov)
3206 memcpy(rw->fast_iov + iov_off, fast_iov + iov_off,
3207 sizeof(struct iovec) * iter->nr_segs);
3208 } else {
3209 req->flags |= REQ_F_NEED_CLEANUP;
3210 }
3211}
3212
3213static inline int __io_alloc_async_data(struct io_kiocb *req)
3214{
3215 WARN_ON_ONCE(!io_op_defs[req->opcode].async_size);
3216 req->async_data = kmalloc(io_op_defs[req->opcode].async_size, GFP_KERNEL);
3217 return req->async_data == NULL;
3218}
3219
3220static int io_alloc_async_data(struct io_kiocb *req)
3221{
3222 if (!io_op_defs[req->opcode].needs_async_data)
3223 return 0;
3224
3225 return __io_alloc_async_data(req);
3226}
3227
3228static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec,
3229 const struct iovec *fast_iov,
3230 struct iov_iter *iter, bool force)
3231{
3232 if (!force && !io_op_defs[req->opcode].needs_async_data)
3233 return 0;
3234 if (!req->async_data) {
3235 if (__io_alloc_async_data(req))
3236 return -ENOMEM;
3237
3238 io_req_map_rw(req, iovec, fast_iov, iter);
3239 }
3240 return 0;
3241}
3242
3243static inline int io_rw_prep_async(struct io_kiocb *req, int rw)
3244{
3245 struct io_async_rw *iorw = req->async_data;
3246 struct iovec *iov = iorw->fast_iov;
3247 ssize_t ret;
3248
3249 ret = __io_import_iovec(rw, req, &iov, &iorw->iter, false);
3250 if (unlikely(ret < 0))
3251 return ret;
3252
3253 iorw->bytes_done = 0;
3254 iorw->free_iovec = iov;
3255 if (iov)
3256 req->flags |= REQ_F_NEED_CLEANUP;
3257 return 0;
3258}
3259
3260static int io_read_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
3261{
3262 ssize_t ret;
3263
3264 ret = io_prep_rw(req, sqe);
3265 if (ret)
3266 return ret;
3267
3268 if (unlikely(!(req->file->f_mode & FMODE_READ)))
3269 return -EBADF;
3270
3271 /* either don't need iovec imported or already have it */
3272 if (!req->async_data)
3273 return 0;
3274 return io_rw_prep_async(req, READ);
3275}
3276
3277/*
3278 * This is our waitqueue callback handler, registered through lock_page_async()
3279 * when we initially tried to do the IO with the iocb armed our waitqueue.
3280 * This gets called when the page is unlocked, and we generally expect that to
3281 * happen when the page IO is completed and the page is now uptodate. This will
3282 * queue a task_work based retry of the operation, attempting to copy the data
3283 * again. If the latter fails because the page was NOT uptodate, then we will
3284 * do a thread based blocking retry of the operation. That's the unexpected
3285 * slow path.
3286 */
3287static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode,
3288 int sync, void *arg)
3289{
3290 struct wait_page_queue *wpq;
3291 struct io_kiocb *req = wait->private;
3292 struct wait_page_key *key = arg;
3293 int ret;
3294
3295 wpq = container_of(wait, struct wait_page_queue, wait);
3296
3297 if (!wake_page_match(wpq, key))
3298 return 0;
3299
3300 req->rw.kiocb.ki_flags &= ~IOCB_WAITQ;
3301 list_del_init(&wait->entry);
3302
3303 init_task_work(&req->task_work, io_req_task_submit);
3304 percpu_ref_get(&req->ctx->refs);
3305
3306 /* submit ref gets dropped, acquire a new one */
3307 refcount_inc(&req->refs);
3308 ret = io_req_task_work_add(req, true);
3309 if (unlikely(ret)) {
3310 struct task_struct *tsk;
3311
3312 /* queue just for cancelation */
3313 init_task_work(&req->task_work, io_req_task_cancel);
3314 tsk = io_wq_get_task(req->ctx->io_wq);
3315 task_work_add(tsk, &req->task_work, TWA_NONE);
3316 wake_up_process(tsk);
3317 }
3318 return 1;
3319}
3320
3321/*
3322 * This controls whether a given IO request should be armed for async page
3323 * based retry. If we return false here, the request is handed to the async
3324 * worker threads for retry. If we're doing buffered reads on a regular file,
3325 * we prepare a private wait_page_queue entry and retry the operation. This
3326 * will either succeed because the page is now uptodate and unlocked, or it
3327 * will register a callback when the page is unlocked at IO completion. Through
3328 * that callback, io_uring uses task_work to setup a retry of the operation.
3329 * That retry will attempt the buffered read again. The retry will generally
3330 * succeed, or in rare cases where it fails, we then fall back to using the
3331 * async worker threads for a blocking retry.
3332 */
3333static bool io_rw_should_retry(struct io_kiocb *req)
3334{
3335 struct io_async_rw *rw = req->async_data;
3336 struct wait_page_queue *wait = &rw->wpq;
3337 struct kiocb *kiocb = &req->rw.kiocb;
3338
3339 /* never retry for NOWAIT, we just complete with -EAGAIN */
3340 if (req->flags & REQ_F_NOWAIT)
3341 return false;
3342
3343 /* Only for buffered IO */
3344 if (kiocb->ki_flags & (IOCB_DIRECT | IOCB_HIPRI))
3345 return false;
3346
3347 /*
3348 * just use poll if we can, and don't attempt if the fs doesn't
3349 * support callback based unlocks
3350 */
3351 if (file_can_poll(req->file) || !(req->file->f_mode & FMODE_BUF_RASYNC))
3352 return false;
3353
3354 wait->wait.func = io_async_buf_func;
3355 wait->wait.private = req;
3356 wait->wait.flags = 0;
3357 INIT_LIST_HEAD(&wait->wait.entry);
3358 kiocb->ki_flags |= IOCB_WAITQ;
3359 kiocb->ki_flags &= ~IOCB_NOWAIT;
3360 kiocb->ki_waitq = wait;
3361 return true;
3362}
3363
3364static int io_iter_do_read(struct io_kiocb *req, struct iov_iter *iter)
3365{
3366 if (req->file->f_op->read_iter)
3367 return call_read_iter(req->file, &req->rw.kiocb, iter);
3368 else if (req->file->f_op->read)
3369 return loop_rw_iter(READ, req, iter);
3370 else
3371 return -EINVAL;
3372}
3373
3374static int io_read(struct io_kiocb *req, bool force_nonblock,
3375 struct io_comp_state *cs)
3376{
3377 struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
3378 struct kiocb *kiocb = &req->rw.kiocb;
3379 struct iov_iter __iter, *iter = &__iter;
3380 struct io_async_rw *rw = req->async_data;
3381 ssize_t io_size, ret, ret2;
3382 size_t iov_count;
3383 bool no_async;
3384
3385 if (rw)
3386 iter = &rw->iter;
3387
3388 ret = io_import_iovec(READ, req, &iovec, iter, !force_nonblock);
3389 if (ret < 0)
3390 return ret;
3391 iov_count = iov_iter_count(iter);
3392 io_size = ret;
3393 req->result = io_size;
3394 ret = 0;
3395
3396 /* Ensure we clear previously set non-block flag */
3397 if (!force_nonblock)
3398 kiocb->ki_flags &= ~IOCB_NOWAIT;
3399 else
3400 kiocb->ki_flags |= IOCB_NOWAIT;
3401
3402
3403 /* If the file doesn't support async, just async punt */
3404 no_async = force_nonblock && !io_file_supports_async(req->file, READ);
3405 if (no_async)
3406 goto copy_iov;
3407
3408 ret = rw_verify_area(READ, req->file, io_kiocb_ppos(kiocb), iov_count);
3409 if (unlikely(ret))
3410 goto out_free;
3411
3412 ret = io_iter_do_read(req, iter);
3413
3414 if (!ret) {
3415 goto done;
3416 } else if (ret == -EIOCBQUEUED) {
3417 ret = 0;
3418 goto out_free;
3419 } else if (ret == -EAGAIN) {
3420 /* IOPOLL retry should happen for io-wq threads */
3421 if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL))
3422 goto done;
3423 /* no retry on NONBLOCK marked file */
3424 if (req->file->f_flags & O_NONBLOCK)
3425 goto done;
3426 /* some cases will consume bytes even on error returns */
3427 iov_iter_revert(iter, iov_count - iov_iter_count(iter));
3428 ret = 0;
3429 goto copy_iov;
3430 } else if (ret < 0) {
3431 /* make sure -ERESTARTSYS -> -EINTR is done */
3432 goto done;
3433 }
3434
3435 /* read it all, or we did blocking attempt. no retry. */
3436 if (!iov_iter_count(iter) || !force_nonblock ||
3437 (req->file->f_flags & O_NONBLOCK))
3438 goto done;
3439
3440 io_size -= ret;
3441copy_iov:
3442 ret2 = io_setup_async_rw(req, iovec, inline_vecs, iter, true);
3443 if (ret2) {
3444 ret = ret2;
3445 goto out_free;
3446 }
3447 if (no_async)
3448 return -EAGAIN;
3449 rw = req->async_data;
3450 /* it's copied and will be cleaned with ->io */
3451 iovec = NULL;
3452 /* now use our persistent iterator, if we aren't already */
3453 iter = &rw->iter;
3454retry:
3455 rw->bytes_done += ret;
3456 /* if we can retry, do so with the callbacks armed */
3457 if (!io_rw_should_retry(req)) {
3458 kiocb->ki_flags &= ~IOCB_WAITQ;
3459 return -EAGAIN;
3460 }
3461
3462 /*
3463 * Now retry read with the IOCB_WAITQ parts set in the iocb. If we
3464 * get -EIOCBQUEUED, then we'll get a notification when the desired
3465 * page gets unlocked. We can also get a partial read here, and if we
3466 * do, then just retry at the new offset.
3467 */
3468 ret = io_iter_do_read(req, iter);
3469 if (ret == -EIOCBQUEUED) {
3470 ret = 0;
3471 goto out_free;
3472 } else if (ret > 0 && ret < io_size) {
3473 /* we got some bytes, but not all. retry. */
3474 goto retry;
3475 }
3476done:
3477 kiocb_done(kiocb, ret, cs);
3478 ret = 0;
3479out_free:
3480 /* it's reportedly faster than delegating the null check to kfree() */
3481 if (iovec)
3482 kfree(iovec);
3483 return ret;
3484}
3485
3486static int io_write_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
3487{
3488 ssize_t ret;
3489
3490 ret = io_prep_rw(req, sqe);
3491 if (ret)
3492 return ret;
3493
3494 if (unlikely(!(req->file->f_mode & FMODE_WRITE)))
3495 return -EBADF;
3496
3497 /* either don't need iovec imported or already have it */
3498 if (!req->async_data)
3499 return 0;
3500 return io_rw_prep_async(req, WRITE);
3501}
3502
3503static int io_write(struct io_kiocb *req, bool force_nonblock,
3504 struct io_comp_state *cs)
3505{
3506 struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
3507 struct kiocb *kiocb = &req->rw.kiocb;
3508 struct iov_iter __iter, *iter = &__iter;
3509 struct io_async_rw *rw = req->async_data;
3510 size_t iov_count;
3511 ssize_t ret, ret2, io_size;
3512
3513 if (rw)
3514 iter = &rw->iter;
3515
3516 ret = io_import_iovec(WRITE, req, &iovec, iter, !force_nonblock);
3517 if (ret < 0)
3518 return ret;
3519 iov_count = iov_iter_count(iter);
3520 io_size = ret;
3521 req->result = io_size;
3522
3523 /* Ensure we clear previously set non-block flag */
3524 if (!force_nonblock)
3525 kiocb->ki_flags &= ~IOCB_NOWAIT;
3526 else
3527 kiocb->ki_flags |= IOCB_NOWAIT;
3528
3529 /* If the file doesn't support async, just async punt */
3530 if (force_nonblock && !io_file_supports_async(req->file, WRITE))
3531 goto copy_iov;
3532
3533 /* file path doesn't support NOWAIT for non-direct_IO */
3534 if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT) &&
3535 (req->flags & REQ_F_ISREG))
3536 goto copy_iov;
3537
3538 ret = rw_verify_area(WRITE, req->file, io_kiocb_ppos(kiocb), iov_count);
3539 if (unlikely(ret))
3540 goto out_free;
3541
3542 /*
3543 * Open-code file_start_write here to grab freeze protection,
3544 * which will be released by another thread in
3545 * io_complete_rw(). Fool lockdep by telling it the lock got
3546 * released so that it doesn't complain about the held lock when
3547 * we return to userspace.
3548 */
3549 if (req->flags & REQ_F_ISREG) {
3550 sb_start_write(file_inode(req->file)->i_sb);
3551 __sb_writers_release(file_inode(req->file)->i_sb,
3552 SB_FREEZE_WRITE);
3553 }
3554 kiocb->ki_flags |= IOCB_WRITE;
3555
3556 if (req->file->f_op->write_iter)
3557 ret2 = call_write_iter(req->file, kiocb, iter);
3558 else if (req->file->f_op->write)
3559 ret2 = loop_rw_iter(WRITE, req, iter);
3560 else
3561 ret2 = -EINVAL;
3562
3563 /*
3564 * Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just
3565 * retry them without IOCB_NOWAIT.
3566 */
3567 if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT))
3568 ret2 = -EAGAIN;
3569 /* no retry on NONBLOCK marked file */
3570 if (ret2 == -EAGAIN && (req->file->f_flags & O_NONBLOCK))
3571 goto done;
3572 if (!force_nonblock || ret2 != -EAGAIN) {
3573 /* IOPOLL retry should happen for io-wq threads */
3574 if ((req->ctx->flags & IORING_SETUP_IOPOLL) && ret2 == -EAGAIN)
3575 goto copy_iov;
3576done:
3577 kiocb_done(kiocb, ret2, cs);
3578 } else {
3579copy_iov:
3580 /* some cases will consume bytes even on error returns */
3581 iov_iter_revert(iter, iov_count - iov_iter_count(iter));
3582 ret = io_setup_async_rw(req, iovec, inline_vecs, iter, false);
3583 if (!ret)
3584 return -EAGAIN;
3585 }
3586out_free:
3587 /* it's reportedly faster than delegating the null check to kfree() */
3588 if (iovec)
3589 kfree(iovec);
3590 return ret;
3591}
3592
3593static int __io_splice_prep(struct io_kiocb *req,
3594 const struct io_uring_sqe *sqe)
3595{
3596 struct io_splice* sp = &req->splice;
3597 unsigned int valid_flags = SPLICE_F_FD_IN_FIXED | SPLICE_F_ALL;
3598
3599 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
3600 return -EINVAL;
3601
3602 sp->file_in = NULL;
3603 sp->len = READ_ONCE(sqe->len);
3604 sp->flags = READ_ONCE(sqe->splice_flags);
3605
3606 if (unlikely(sp->flags & ~valid_flags))
3607 return -EINVAL;
3608
3609 sp->file_in = io_file_get(NULL, req, READ_ONCE(sqe->splice_fd_in),
3610 (sp->flags & SPLICE_F_FD_IN_FIXED));
3611 if (!sp->file_in)
3612 return -EBADF;
3613 req->flags |= REQ_F_NEED_CLEANUP;
3614
3615 if (!S_ISREG(file_inode(sp->file_in)->i_mode)) {
3616 /*
3617 * Splice operation will be punted aync, and here need to
3618 * modify io_wq_work.flags, so initialize io_wq_work firstly.
3619 */
3620 io_req_init_async(req);
3621 req->work.flags |= IO_WQ_WORK_UNBOUND;
3622 }
3623
3624 return 0;
3625}
3626
3627static int io_tee_prep(struct io_kiocb *req,
3628 const struct io_uring_sqe *sqe)
3629{
3630 if (READ_ONCE(sqe->splice_off_in) || READ_ONCE(sqe->off))
3631 return -EINVAL;
3632 return __io_splice_prep(req, sqe);
3633}
3634
3635static int io_tee(struct io_kiocb *req, bool force_nonblock)
3636{
3637 struct io_splice *sp = &req->splice;
3638 struct file *in = sp->file_in;
3639 struct file *out = sp->file_out;
3640 unsigned int flags = sp->flags & ~SPLICE_F_FD_IN_FIXED;
3641 long ret = 0;
3642
3643 if (force_nonblock)
3644 return -EAGAIN;
3645 if (sp->len)
3646 ret = do_tee(in, out, sp->len, flags);
3647
3648 io_put_file(req, in, (sp->flags & SPLICE_F_FD_IN_FIXED));
3649 req->flags &= ~REQ_F_NEED_CLEANUP;
3650
3651 if (ret != sp->len)
3652 req_set_fail_links(req);
3653 io_req_complete(req, ret);
3654 return 0;
3655}
3656
3657static int io_splice_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
3658{
3659 struct io_splice* sp = &req->splice;
3660
3661 sp->off_in = READ_ONCE(sqe->splice_off_in);
3662 sp->off_out = READ_ONCE(sqe->off);
3663 return __io_splice_prep(req, sqe);
3664}
3665
3666static int io_splice(struct io_kiocb *req, bool force_nonblock)
3667{
3668 struct io_splice *sp = &req->splice;
3669 struct file *in = sp->file_in;
3670 struct file *out = sp->file_out;
3671 unsigned int flags = sp->flags & ~SPLICE_F_FD_IN_FIXED;
3672 loff_t *poff_in, *poff_out;
3673 long ret = 0;
3674
3675 if (force_nonblock)
3676 return -EAGAIN;
3677
3678 poff_in = (sp->off_in == -1) ? NULL : &sp->off_in;
3679 poff_out = (sp->off_out == -1) ? NULL : &sp->off_out;
3680
3681 if (sp->len)
3682 ret = do_splice(in, poff_in, out, poff_out, sp->len, flags);
3683
3684 io_put_file(req, in, (sp->flags & SPLICE_F_FD_IN_FIXED));
3685 req->flags &= ~REQ_F_NEED_CLEANUP;
3686
3687 if (ret != sp->len)
3688 req_set_fail_links(req);
3689 io_req_complete(req, ret);
3690 return 0;
3691}
3692
3693/*
3694 * IORING_OP_NOP just posts a completion event, nothing else.
3695 */
3696static int io_nop(struct io_kiocb *req, struct io_comp_state *cs)
3697{
3698 struct io_ring_ctx *ctx = req->ctx;
3699
3700 if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
3701 return -EINVAL;
3702
3703 __io_req_complete(req, 0, 0, cs);
3704 return 0;
3705}
3706
3707static int io_prep_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe)
3708{
3709 struct io_ring_ctx *ctx = req->ctx;
3710
3711 if (!req->file)
3712 return -EBADF;
3713
3714 if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
3715 return -EINVAL;
3716 if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index))
3717 return -EINVAL;
3718
3719 req->sync.flags = READ_ONCE(sqe->fsync_flags);
3720 if (unlikely(req->sync.flags & ~IORING_FSYNC_DATASYNC))
3721 return -EINVAL;
3722
3723 req->sync.off = READ_ONCE(sqe->off);
3724 req->sync.len = READ_ONCE(sqe->len);
3725 return 0;
3726}
3727
3728static int io_fsync(struct io_kiocb *req, bool force_nonblock)
3729{
3730 loff_t end = req->sync.off + req->sync.len;
3731 int ret;
3732
3733 /* fsync always requires a blocking context */
3734 if (force_nonblock)
3735 return -EAGAIN;
3736
3737 ret = vfs_fsync_range(req->file, req->sync.off,
3738 end > 0 ? end : LLONG_MAX,
3739 req->sync.flags & IORING_FSYNC_DATASYNC);
3740 if (ret < 0)
3741 req_set_fail_links(req);
3742 io_req_complete(req, ret);
3743 return 0;
3744}
3745
3746static int io_fallocate_prep(struct io_kiocb *req,
3747 const struct io_uring_sqe *sqe)
3748{
3749 if (sqe->ioprio || sqe->buf_index || sqe->rw_flags)
3750 return -EINVAL;
3751 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
3752 return -EINVAL;
3753
3754 req->sync.off = READ_ONCE(sqe->off);
3755 req->sync.len = READ_ONCE(sqe->addr);
3756 req->sync.mode = READ_ONCE(sqe->len);
3757 return 0;
3758}
3759
3760static int io_fallocate(struct io_kiocb *req, bool force_nonblock)
3761{
3762 int ret;
3763
3764 /* fallocate always requiring blocking context */
3765 if (force_nonblock)
3766 return -EAGAIN;
3767 ret = vfs_fallocate(req->file, req->sync.mode, req->sync.off,
3768 req->sync.len);
3769 if (ret < 0)
3770 req_set_fail_links(req);
3771 io_req_complete(req, ret);
3772 return 0;
3773}
3774
3775static int __io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
3776{
3777 const char __user *fname;
3778 int ret;
3779
3780 if (unlikely(sqe->ioprio || sqe->buf_index))
3781 return -EINVAL;
3782 if (unlikely(req->flags & REQ_F_FIXED_FILE))
3783 return -EBADF;
3784
3785 /* open.how should be already initialised */
3786 if (!(req->open.how.flags & O_PATH) && force_o_largefile())
3787 req->open.how.flags |= O_LARGEFILE;
3788
3789 req->open.dfd = READ_ONCE(sqe->fd);
3790 fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
3791 req->open.filename = getname(fname);
3792 if (IS_ERR(req->open.filename)) {
3793 ret = PTR_ERR(req->open.filename);
3794 req->open.filename = NULL;
3795 return ret;
3796 }
3797 req->open.nofile = rlimit(RLIMIT_NOFILE);
3798 req->open.ignore_nonblock = false;
3799 req->flags |= REQ_F_NEED_CLEANUP;
3800 return 0;
3801}
3802
3803static int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
3804{
3805 u64 flags, mode;
3806
3807 if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
3808 return -EINVAL;
3809 mode = READ_ONCE(sqe->len);
3810 flags = READ_ONCE(sqe->open_flags);
3811 req->open.how = build_open_how(flags, mode);
3812 return __io_openat_prep(req, sqe);
3813}
3814
3815static int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
3816{
3817 struct open_how __user *how;
3818 size_t len;
3819 int ret;
3820
3821 if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
3822 return -EINVAL;
3823 how = u64_to_user_ptr(READ_ONCE(sqe->addr2));
3824 len = READ_ONCE(sqe->len);
3825 if (len < OPEN_HOW_SIZE_VER0)
3826 return -EINVAL;
3827
3828 ret = copy_struct_from_user(&req->open.how, sizeof(req->open.how), how,
3829 len);
3830 if (ret)
3831 return ret;
3832
3833 return __io_openat_prep(req, sqe);
3834}
3835
3836static int io_openat2(struct io_kiocb *req, bool force_nonblock)
3837{
3838 struct open_flags op;
3839 struct file *file;
3840 int ret;
3841
3842 if (force_nonblock && !req->open.ignore_nonblock)
3843 return -EAGAIN;
3844
3845 ret = build_open_flags(&req->open.how, &op);
3846 if (ret)
3847 goto err;
3848
3849 ret = __get_unused_fd_flags(req->open.how.flags, req->open.nofile);
3850 if (ret < 0)
3851 goto err;
3852
3853 file = do_filp_open(req->open.dfd, req->open.filename, &op);
3854 if (IS_ERR(file)) {
3855 put_unused_fd(ret);
3856 ret = PTR_ERR(file);
3857 /*
3858 * A work-around to ensure that /proc/self works that way
3859 * that it should - if we get -EOPNOTSUPP back, then assume
3860 * that proc_self_get_link() failed us because we're in async
3861 * context. We should be safe to retry this from the task
3862 * itself with force_nonblock == false set, as it should not
3863 * block on lookup. Would be nice to know this upfront and
3864 * avoid the async dance, but doesn't seem feasible.
3865 */
3866 if (ret == -EOPNOTSUPP && io_wq_current_is_worker()) {
3867 req->open.ignore_nonblock = true;
3868 refcount_inc(&req->refs);
3869 io_req_task_queue(req);
3870 return 0;
3871 }
3872 } else {
3873 fsnotify_open(file);
3874 fd_install(ret, file);
3875 }
3876err:
3877 putname(req->open.filename);
3878 req->flags &= ~REQ_F_NEED_CLEANUP;
3879 if (ret < 0)
3880 req_set_fail_links(req);
3881 io_req_complete(req, ret);
3882 return 0;
3883}
3884
3885static int io_openat(struct io_kiocb *req, bool force_nonblock)
3886{
3887 return io_openat2(req, force_nonblock);
3888}
3889
3890static int io_remove_buffers_prep(struct io_kiocb *req,
3891 const struct io_uring_sqe *sqe)
3892{
3893 struct io_provide_buf *p = &req->pbuf;
3894 u64 tmp;
3895
3896 if (sqe->ioprio || sqe->rw_flags || sqe->addr || sqe->len || sqe->off)
3897 return -EINVAL;
3898
3899 tmp = READ_ONCE(sqe->fd);
3900 if (!tmp || tmp > USHRT_MAX)
3901 return -EINVAL;
3902
3903 memset(p, 0, sizeof(*p));
3904 p->nbufs = tmp;
3905 p->bgid = READ_ONCE(sqe->buf_group);
3906 return 0;
3907}
3908
3909static int __io_remove_buffers(struct io_ring_ctx *ctx, struct io_buffer *buf,
3910 int bgid, unsigned nbufs)
3911{
3912 unsigned i = 0;
3913
3914 /* shouldn't happen */
3915 if (!nbufs)
3916 return 0;
3917
3918 /* the head kbuf is the list itself */
3919 while (!list_empty(&buf->list)) {
3920 struct io_buffer *nxt;
3921
3922 nxt = list_first_entry(&buf->list, struct io_buffer, list);
3923 list_del(&nxt->list);
3924 kfree(nxt);
3925 if (++i == nbufs)
3926 return i;
3927 }
3928 i++;
3929 kfree(buf);
3930 idr_remove(&ctx->io_buffer_idr, bgid);
3931
3932 return i;
3933}
3934
3935static int io_remove_buffers(struct io_kiocb *req, bool force_nonblock,
3936 struct io_comp_state *cs)
3937{
3938 struct io_provide_buf *p = &req->pbuf;
3939 struct io_ring_ctx *ctx = req->ctx;
3940 struct io_buffer *head;
3941 int ret = 0;
3942
3943 io_ring_submit_lock(ctx, !force_nonblock);
3944
3945 lockdep_assert_held(&ctx->uring_lock);
3946
3947 ret = -ENOENT;
3948 head = idr_find(&ctx->io_buffer_idr, p->bgid);
3949 if (head)
3950 ret = __io_remove_buffers(ctx, head, p->bgid, p->nbufs);
3951
3952 io_ring_submit_lock(ctx, !force_nonblock);
3953 if (ret < 0)
3954 req_set_fail_links(req);
3955 __io_req_complete(req, ret, 0, cs);
3956 return 0;
3957}
3958
3959static int io_provide_buffers_prep(struct io_kiocb *req,
3960 const struct io_uring_sqe *sqe)
3961{
3962 struct io_provide_buf *p = &req->pbuf;
3963 u64 tmp;
3964
3965 if (sqe->ioprio || sqe->rw_flags)
3966 return -EINVAL;
3967
3968 tmp = READ_ONCE(sqe->fd);
3969 if (!tmp || tmp > USHRT_MAX)
3970 return -E2BIG;
3971 p->nbufs = tmp;
3972 p->addr = READ_ONCE(sqe->addr);
3973 p->len = READ_ONCE(sqe->len);
3974
3975 if (!access_ok(u64_to_user_ptr(p->addr), (p->len * p->nbufs)))
3976 return -EFAULT;
3977
3978 p->bgid = READ_ONCE(sqe->buf_group);
3979 tmp = READ_ONCE(sqe->off);
3980 if (tmp > USHRT_MAX)
3981 return -E2BIG;
3982 p->bid = tmp;
3983 return 0;
3984}
3985
3986static int io_add_buffers(struct io_provide_buf *pbuf, struct io_buffer **head)
3987{
3988 struct io_buffer *buf;
3989 u64 addr = pbuf->addr;
3990 int i, bid = pbuf->bid;
3991
3992 for (i = 0; i < pbuf->nbufs; i++) {
3993 buf = kmalloc(sizeof(*buf), GFP_KERNEL);
3994 if (!buf)
3995 break;
3996
3997 buf->addr = addr;
3998 buf->len = pbuf->len;
3999 buf->bid = bid;
4000 addr += pbuf->len;
4001 bid++;
4002 if (!*head) {
4003 INIT_LIST_HEAD(&buf->list);
4004 *head = buf;
4005 } else {
4006 list_add_tail(&buf->list, &(*head)->list);
4007 }
4008 }
4009
4010 return i ? i : -ENOMEM;
4011}
4012
4013static int io_provide_buffers(struct io_kiocb *req, bool force_nonblock,
4014 struct io_comp_state *cs)
4015{
4016 struct io_provide_buf *p = &req->pbuf;
4017 struct io_ring_ctx *ctx = req->ctx;
4018 struct io_buffer *head, *list;
4019 int ret = 0;
4020
4021 io_ring_submit_lock(ctx, !force_nonblock);
4022
4023 lockdep_assert_held(&ctx->uring_lock);
4024
4025 list = head = idr_find(&ctx->io_buffer_idr, p->bgid);
4026
4027 ret = io_add_buffers(p, &head);
4028 if (ret < 0)
4029 goto out;
4030
4031 if (!list) {
4032 ret = idr_alloc(&ctx->io_buffer_idr, head, p->bgid, p->bgid + 1,
4033 GFP_KERNEL);
4034 if (ret < 0) {
4035 __io_remove_buffers(ctx, head, p->bgid, -1U);
4036 goto out;
4037 }
4038 }
4039out:
4040 io_ring_submit_unlock(ctx, !force_nonblock);
4041 if (ret < 0)
4042 req_set_fail_links(req);
4043 __io_req_complete(req, ret, 0, cs);
4044 return 0;
4045}
4046
4047static int io_epoll_ctl_prep(struct io_kiocb *req,
4048 const struct io_uring_sqe *sqe)
4049{
4050#if defined(CONFIG_EPOLL)
4051 if (sqe->ioprio || sqe->buf_index)
4052 return -EINVAL;
4053 if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL)))
4054 return -EINVAL;
4055
4056 req->epoll.epfd = READ_ONCE(sqe->fd);
4057 req->epoll.op = READ_ONCE(sqe->len);
4058 req->epoll.fd = READ_ONCE(sqe->off);
4059
4060 if (ep_op_has_event(req->epoll.op)) {
4061 struct epoll_event __user *ev;
4062
4063 ev = u64_to_user_ptr(READ_ONCE(sqe->addr));
4064 if (copy_from_user(&req->epoll.event, ev, sizeof(*ev)))
4065 return -EFAULT;
4066 }
4067
4068 return 0;
4069#else
4070 return -EOPNOTSUPP;
4071#endif
4072}
4073
4074static int io_epoll_ctl(struct io_kiocb *req, bool force_nonblock,
4075 struct io_comp_state *cs)
4076{
4077#if defined(CONFIG_EPOLL)
4078 struct io_epoll *ie = &req->epoll;
4079 int ret;
4080
4081 ret = do_epoll_ctl(ie->epfd, ie->op, ie->fd, &ie->event, force_nonblock);
4082 if (force_nonblock && ret == -EAGAIN)
4083 return -EAGAIN;
4084
4085 if (ret < 0)
4086 req_set_fail_links(req);
4087 __io_req_complete(req, ret, 0, cs);
4088 return 0;
4089#else
4090 return -EOPNOTSUPP;
4091#endif
4092}
4093
4094static int io_madvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4095{
4096#if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU)
4097 if (sqe->ioprio || sqe->buf_index || sqe->off)
4098 return -EINVAL;
4099 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
4100 return -EINVAL;
4101
4102 req->madvise.addr = READ_ONCE(sqe->addr);
4103 req->madvise.len = READ_ONCE(sqe->len);
4104 req->madvise.advice = READ_ONCE(sqe->fadvise_advice);
4105 return 0;
4106#else
4107 return -EOPNOTSUPP;
4108#endif
4109}
4110
4111static int io_madvise(struct io_kiocb *req, bool force_nonblock)
4112{
4113#if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU)
4114 struct io_madvise *ma = &req->madvise;
4115 int ret;
4116
4117 if (force_nonblock)
4118 return -EAGAIN;
4119
4120 ret = do_madvise(current->mm, ma->addr, ma->len, ma->advice);
4121 if (ret < 0)
4122 req_set_fail_links(req);
4123 io_req_complete(req, ret);
4124 return 0;
4125#else
4126 return -EOPNOTSUPP;
4127#endif
4128}
4129
4130static int io_fadvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4131{
4132 if (sqe->ioprio || sqe->buf_index || sqe->addr)
4133 return -EINVAL;
4134 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
4135 return -EINVAL;
4136
4137 req->fadvise.offset = READ_ONCE(sqe->off);
4138 req->fadvise.len = READ_ONCE(sqe->len);
4139 req->fadvise.advice = READ_ONCE(sqe->fadvise_advice);
4140 return 0;
4141}
4142
4143static int io_fadvise(struct io_kiocb *req, bool force_nonblock)
4144{
4145 struct io_fadvise *fa = &req->fadvise;
4146 int ret;
4147
4148 if (force_nonblock) {
4149 switch (fa->advice) {
4150 case POSIX_FADV_NORMAL:
4151 case POSIX_FADV_RANDOM:
4152 case POSIX_FADV_SEQUENTIAL:
4153 break;
4154 default:
4155 return -EAGAIN;
4156 }
4157 }
4158
4159 ret = vfs_fadvise(req->file, fa->offset, fa->len, fa->advice);
4160 if (ret < 0)
4161 req_set_fail_links(req);
4162 io_req_complete(req, ret);
4163 return 0;
4164}
4165
4166static int io_statx_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4167{
4168 if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL)))
4169 return -EINVAL;
4170 if (sqe->ioprio || sqe->buf_index)
4171 return -EINVAL;
4172 if (req->flags & REQ_F_FIXED_FILE)
4173 return -EBADF;
4174
4175 req->statx.dfd = READ_ONCE(sqe->fd);
4176 req->statx.mask = READ_ONCE(sqe->len);
4177 req->statx.filename = u64_to_user_ptr(READ_ONCE(sqe->addr));
4178 req->statx.buffer = u64_to_user_ptr(READ_ONCE(sqe->addr2));
4179 req->statx.flags = READ_ONCE(sqe->statx_flags);
4180
4181 return 0;
4182}
4183
4184static int io_statx(struct io_kiocb *req, bool force_nonblock)
4185{
4186 struct io_statx *ctx = &req->statx;
4187 int ret;
4188
4189 if (force_nonblock) {
4190 /* only need file table for an actual valid fd */
4191 if (ctx->dfd == -1 || ctx->dfd == AT_FDCWD)
4192 req->flags |= REQ_F_NO_FILE_TABLE;
4193 return -EAGAIN;
4194 }
4195
4196 ret = do_statx(ctx->dfd, ctx->filename, ctx->flags, ctx->mask,
4197 ctx->buffer);
4198
4199 if (ret < 0)
4200 req_set_fail_links(req);
4201 io_req_complete(req, ret);
4202 return 0;
4203}
4204
4205static int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4206{
4207 /*
4208 * If we queue this for async, it must not be cancellable. That would
4209 * leave the 'file' in an undeterminate state, and here need to modify
4210 * io_wq_work.flags, so initialize io_wq_work firstly.
4211 */
4212 io_req_init_async(req);
4213 req->work.flags |= IO_WQ_WORK_NO_CANCEL;
4214
4215 if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
4216 return -EINVAL;
4217 if (sqe->ioprio || sqe->off || sqe->addr || sqe->len ||
4218 sqe->rw_flags || sqe->buf_index)
4219 return -EINVAL;
4220 if (req->flags & REQ_F_FIXED_FILE)
4221 return -EBADF;
4222
4223 req->close.fd = READ_ONCE(sqe->fd);
4224 if ((req->file && req->file->f_op == &io_uring_fops))
4225 return -EBADF;
4226
4227 req->close.put_file = NULL;
4228 return 0;
4229}
4230
4231static int io_close(struct io_kiocb *req, bool force_nonblock,
4232 struct io_comp_state *cs)
4233{
4234 struct io_close *close = &req->close;
4235 int ret;
4236
4237 /* might be already done during nonblock submission */
4238 if (!close->put_file) {
4239 ret = __close_fd_get_file(close->fd, &close->put_file);
4240 if (ret < 0)
4241 return (ret == -ENOENT) ? -EBADF : ret;
4242 }
4243
4244 /* if the file has a flush method, be safe and punt to async */
4245 if (close->put_file->f_op->flush && force_nonblock) {
4246 /* was never set, but play safe */
4247 req->flags &= ~REQ_F_NOWAIT;
4248 /* avoid grabbing files - we don't need the files */
4249 req->flags |= REQ_F_NO_FILE_TABLE;
4250 return -EAGAIN;
4251 }
4252
4253 /* No ->flush() or already async, safely close from here */
4254 ret = filp_close(close->put_file, req->work.identity->files);
4255 if (ret < 0)
4256 req_set_fail_links(req);
4257 fput(close->put_file);
4258 close->put_file = NULL;
4259 __io_req_complete(req, ret, 0, cs);
4260 return 0;
4261}
4262
4263static int io_prep_sfr(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4264{
4265 struct io_ring_ctx *ctx = req->ctx;
4266
4267 if (!req->file)
4268 return -EBADF;
4269
4270 if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
4271 return -EINVAL;
4272 if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index))
4273 return -EINVAL;
4274
4275 req->sync.off = READ_ONCE(sqe->off);
4276 req->sync.len = READ_ONCE(sqe->len);
4277 req->sync.flags = READ_ONCE(sqe->sync_range_flags);
4278 return 0;
4279}
4280
4281static int io_sync_file_range(struct io_kiocb *req, bool force_nonblock)
4282{
4283 int ret;
4284
4285 /* sync_file_range always requires a blocking context */
4286 if (force_nonblock)
4287 return -EAGAIN;
4288
4289 ret = sync_file_range(req->file, req->sync.off, req->sync.len,
4290 req->sync.flags);
4291 if (ret < 0)
4292 req_set_fail_links(req);
4293 io_req_complete(req, ret);
4294 return 0;
4295}
4296
4297#if defined(CONFIG_NET)
4298static int io_setup_async_msg(struct io_kiocb *req,
4299 struct io_async_msghdr *kmsg)
4300{
4301 struct io_async_msghdr *async_msg = req->async_data;
4302
4303 if (async_msg)
4304 return -EAGAIN;
4305 if (io_alloc_async_data(req)) {
4306 if (kmsg->iov != kmsg->fast_iov)
4307 kfree(kmsg->iov);
4308 return -ENOMEM;
4309 }
4310 async_msg = req->async_data;
4311 req->flags |= REQ_F_NEED_CLEANUP;
4312 memcpy(async_msg, kmsg, sizeof(*kmsg));
4313 return -EAGAIN;
4314}
4315
4316static int io_sendmsg_copy_hdr(struct io_kiocb *req,
4317 struct io_async_msghdr *iomsg)
4318{
4319 iomsg->iov = iomsg->fast_iov;
4320 iomsg->msg.msg_name = &iomsg->addr;
4321 return sendmsg_copy_msghdr(&iomsg->msg, req->sr_msg.umsg,
4322 req->sr_msg.msg_flags, &iomsg->iov);
4323}
4324
4325static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4326{
4327 struct io_async_msghdr *async_msg = req->async_data;
4328 struct io_sr_msg *sr = &req->sr_msg;
4329 int ret;
4330
4331 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
4332 return -EINVAL;
4333
4334 sr->msg_flags = READ_ONCE(sqe->msg_flags);
4335 sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
4336 sr->len = READ_ONCE(sqe->len);
4337
4338#ifdef CONFIG_COMPAT
4339 if (req->ctx->compat)
4340 sr->msg_flags |= MSG_CMSG_COMPAT;
4341#endif
4342
4343 if (!async_msg || !io_op_defs[req->opcode].needs_async_data)
4344 return 0;
4345 ret = io_sendmsg_copy_hdr(req, async_msg);
4346 if (!ret)
4347 req->flags |= REQ_F_NEED_CLEANUP;
4348 return ret;
4349}
4350
4351static int io_sendmsg(struct io_kiocb *req, bool force_nonblock,
4352 struct io_comp_state *cs)
4353{
4354 struct io_async_msghdr iomsg, *kmsg;
4355 struct socket *sock;
4356 unsigned flags;
4357 int ret;
4358
4359 sock = sock_from_file(req->file, &ret);
4360 if (unlikely(!sock))
4361 return ret;
4362
4363 if (req->async_data) {
4364 kmsg = req->async_data;
4365 kmsg->msg.msg_name = &kmsg->addr;
4366 /* if iov is set, it's allocated already */
4367 if (!kmsg->iov)
4368 kmsg->iov = kmsg->fast_iov;
4369 kmsg->msg.msg_iter.iov = kmsg->iov;
4370 } else {
4371 ret = io_sendmsg_copy_hdr(req, &iomsg);
4372 if (ret)
4373 return ret;
4374 kmsg = &iomsg;
4375 }
4376
4377 flags = req->sr_msg.msg_flags;
4378 if (flags & MSG_DONTWAIT)
4379 req->flags |= REQ_F_NOWAIT;
4380 else if (force_nonblock)
4381 flags |= MSG_DONTWAIT;
4382
4383 ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
4384 if (force_nonblock && ret == -EAGAIN)
4385 return io_setup_async_msg(req, kmsg);
4386 if (ret == -ERESTARTSYS)
4387 ret = -EINTR;
4388
4389 if (kmsg->iov != kmsg->fast_iov)
4390 kfree(kmsg->iov);
4391 req->flags &= ~REQ_F_NEED_CLEANUP;
4392 if (ret < 0)
4393 req_set_fail_links(req);
4394 __io_req_complete(req, ret, 0, cs);
4395 return 0;
4396}
4397
4398static int io_send(struct io_kiocb *req, bool force_nonblock,
4399 struct io_comp_state *cs)
4400{
4401 struct io_sr_msg *sr = &req->sr_msg;
4402 struct msghdr msg;
4403 struct iovec iov;
4404 struct socket *sock;
4405 unsigned flags;
4406 int ret;
4407
4408 sock = sock_from_file(req->file, &ret);
4409 if (unlikely(!sock))
4410 return ret;
4411
4412 ret = import_single_range(WRITE, sr->buf, sr->len, &iov, &msg.msg_iter);
4413 if (unlikely(ret))
4414 return ret;
4415
4416 msg.msg_name = NULL;
4417 msg.msg_control = NULL;
4418 msg.msg_controllen = 0;
4419 msg.msg_namelen = 0;
4420
4421 flags = req->sr_msg.msg_flags;
4422 if (flags & MSG_DONTWAIT)
4423 req->flags |= REQ_F_NOWAIT;
4424 else if (force_nonblock)
4425 flags |= MSG_DONTWAIT;
4426
4427 msg.msg_flags = flags;
4428 ret = sock_sendmsg(sock, &msg);
4429 if (force_nonblock && ret == -EAGAIN)
4430 return -EAGAIN;
4431 if (ret == -ERESTARTSYS)
4432 ret = -EINTR;
4433
4434 if (ret < 0)
4435 req_set_fail_links(req);
4436 __io_req_complete(req, ret, 0, cs);
4437 return 0;
4438}
4439
4440static int __io_recvmsg_copy_hdr(struct io_kiocb *req,
4441 struct io_async_msghdr *iomsg)
4442{
4443 struct io_sr_msg *sr = &req->sr_msg;
4444 struct iovec __user *uiov;
4445 size_t iov_len;
4446 int ret;
4447
4448 ret = __copy_msghdr_from_user(&iomsg->msg, sr->umsg,
4449 &iomsg->uaddr, &uiov, &iov_len);
4450 if (ret)
4451 return ret;
4452
4453 if (req->flags & REQ_F_BUFFER_SELECT) {
4454 if (iov_len > 1)
4455 return -EINVAL;
4456 if (copy_from_user(iomsg->iov, uiov, sizeof(*uiov)))
4457 return -EFAULT;
4458 sr->len = iomsg->iov[0].iov_len;
4459 iov_iter_init(&iomsg->msg.msg_iter, READ, iomsg->iov, 1,
4460 sr->len);
4461 iomsg->iov = NULL;
4462 } else {
4463 ret = __import_iovec(READ, uiov, iov_len, UIO_FASTIOV,
4464 &iomsg->iov, &iomsg->msg.msg_iter,
4465 false);
4466 if (ret > 0)
4467 ret = 0;
4468 }
4469
4470 return ret;
4471}
4472
4473#ifdef CONFIG_COMPAT
4474static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
4475 struct io_async_msghdr *iomsg)
4476{
4477 struct compat_msghdr __user *msg_compat;
4478 struct io_sr_msg *sr = &req->sr_msg;
4479 struct compat_iovec __user *uiov;
4480 compat_uptr_t ptr;
4481 compat_size_t len;
4482 int ret;
4483
4484 msg_compat = (struct compat_msghdr __user *) sr->umsg;
4485 ret = __get_compat_msghdr(&iomsg->msg, msg_compat, &iomsg->uaddr,
4486 &ptr, &len);
4487 if (ret)
4488 return ret;
4489
4490 uiov = compat_ptr(ptr);
4491 if (req->flags & REQ_F_BUFFER_SELECT) {
4492 compat_ssize_t clen;
4493
4494 if (len > 1)
4495 return -EINVAL;
4496 if (!access_ok(uiov, sizeof(*uiov)))
4497 return -EFAULT;
4498 if (__get_user(clen, &uiov->iov_len))
4499 return -EFAULT;
4500 if (clen < 0)
4501 return -EINVAL;
4502 sr->len = iomsg->iov[0].iov_len;
4503 iomsg->iov = NULL;
4504 } else {
4505 ret = __import_iovec(READ, (struct iovec __user *)uiov, len,
4506 UIO_FASTIOV, &iomsg->iov,
4507 &iomsg->msg.msg_iter, true);
4508 if (ret < 0)
4509 return ret;
4510 }
4511
4512 return 0;
4513}
4514#endif
4515
4516static int io_recvmsg_copy_hdr(struct io_kiocb *req,
4517 struct io_async_msghdr *iomsg)
4518{
4519 iomsg->msg.msg_name = &iomsg->addr;
4520 iomsg->iov = iomsg->fast_iov;
4521
4522#ifdef CONFIG_COMPAT
4523 if (req->ctx->compat)
4524 return __io_compat_recvmsg_copy_hdr(req, iomsg);
4525#endif
4526
4527 return __io_recvmsg_copy_hdr(req, iomsg);
4528}
4529
4530static struct io_buffer *io_recv_buffer_select(struct io_kiocb *req,
4531 bool needs_lock)
4532{
4533 struct io_sr_msg *sr = &req->sr_msg;
4534 struct io_buffer *kbuf;
4535
4536 kbuf = io_buffer_select(req, &sr->len, sr->bgid, sr->kbuf, needs_lock);
4537 if (IS_ERR(kbuf))
4538 return kbuf;
4539
4540 sr->kbuf = kbuf;
4541 req->flags |= REQ_F_BUFFER_SELECTED;
4542 return kbuf;
4543}
4544
4545static inline unsigned int io_put_recv_kbuf(struct io_kiocb *req)
4546{
4547 return io_put_kbuf(req, req->sr_msg.kbuf);
4548}
4549
4550static int io_recvmsg_prep(struct io_kiocb *req,
4551 const struct io_uring_sqe *sqe)
4552{
4553 struct io_async_msghdr *async_msg = req->async_data;
4554 struct io_sr_msg *sr = &req->sr_msg;
4555 int ret;
4556
4557 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
4558 return -EINVAL;
4559
4560 sr->msg_flags = READ_ONCE(sqe->msg_flags);
4561 sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
4562 sr->len = READ_ONCE(sqe->len);
4563 sr->bgid = READ_ONCE(sqe->buf_group);
4564
4565#ifdef CONFIG_COMPAT
4566 if (req->ctx->compat)
4567 sr->msg_flags |= MSG_CMSG_COMPAT;
4568#endif
4569
4570 if (!async_msg || !io_op_defs[req->opcode].needs_async_data)
4571 return 0;
4572 ret = io_recvmsg_copy_hdr(req, async_msg);
4573 if (!ret)
4574 req->flags |= REQ_F_NEED_CLEANUP;
4575 return ret;
4576}
4577
4578static int io_recvmsg(struct io_kiocb *req, bool force_nonblock,
4579 struct io_comp_state *cs)
4580{
4581 struct io_async_msghdr iomsg, *kmsg;
4582 struct socket *sock;
4583 struct io_buffer *kbuf;
4584 unsigned flags;
4585 int ret, cflags = 0;
4586
4587 sock = sock_from_file(req->file, &ret);
4588 if (unlikely(!sock))
4589 return ret;
4590
4591 if (req->async_data) {
4592 kmsg = req->async_data;
4593 kmsg->msg.msg_name = &kmsg->addr;
4594 /* if iov is set, it's allocated already */
4595 if (!kmsg->iov)
4596 kmsg->iov = kmsg->fast_iov;
4597 kmsg->msg.msg_iter.iov = kmsg->iov;
4598 } else {
4599 ret = io_recvmsg_copy_hdr(req, &iomsg);
4600 if (ret)
4601 return ret;
4602 kmsg = &iomsg;
4603 }
4604
4605 if (req->flags & REQ_F_BUFFER_SELECT) {
4606 kbuf = io_recv_buffer_select(req, !force_nonblock);
4607 if (IS_ERR(kbuf))
4608 return PTR_ERR(kbuf);
4609 kmsg->fast_iov[0].iov_base = u64_to_user_ptr(kbuf->addr);
4610 iov_iter_init(&kmsg->msg.msg_iter, READ, kmsg->iov,
4611 1, req->sr_msg.len);
4612 }
4613
4614 flags = req->sr_msg.msg_flags;
4615 if (flags & MSG_DONTWAIT)
4616 req->flags |= REQ_F_NOWAIT;
4617 else if (force_nonblock)
4618 flags |= MSG_DONTWAIT;
4619
4620 ret = __sys_recvmsg_sock(sock, &kmsg->msg, req->sr_msg.umsg,
4621 kmsg->uaddr, flags);
4622 if (force_nonblock && ret == -EAGAIN)
4623 return io_setup_async_msg(req, kmsg);
4624 if (ret == -ERESTARTSYS)
4625 ret = -EINTR;
4626
4627 if (req->flags & REQ_F_BUFFER_SELECTED)
4628 cflags = io_put_recv_kbuf(req);
4629 if (kmsg->iov != kmsg->fast_iov)
4630 kfree(kmsg->iov);
4631 req->flags &= ~REQ_F_NEED_CLEANUP;
4632 if (ret < 0)
4633 req_set_fail_links(req);
4634 __io_req_complete(req, ret, cflags, cs);
4635 return 0;
4636}
4637
4638static int io_recv(struct io_kiocb *req, bool force_nonblock,
4639 struct io_comp_state *cs)
4640{
4641 struct io_buffer *kbuf;
4642 struct io_sr_msg *sr = &req->sr_msg;
4643 struct msghdr msg;
4644 void __user *buf = sr->buf;
4645 struct socket *sock;
4646 struct iovec iov;
4647 unsigned flags;
4648 int ret, cflags = 0;
4649
4650 sock = sock_from_file(req->file, &ret);
4651 if (unlikely(!sock))
4652 return ret;
4653
4654 if (req->flags & REQ_F_BUFFER_SELECT) {
4655 kbuf = io_recv_buffer_select(req, !force_nonblock);
4656 if (IS_ERR(kbuf))
4657 return PTR_ERR(kbuf);
4658 buf = u64_to_user_ptr(kbuf->addr);
4659 }
4660
4661 ret = import_single_range(READ, buf, sr->len, &iov, &msg.msg_iter);
4662 if (unlikely(ret))
4663 goto out_free;
4664
4665 msg.msg_name = NULL;
4666 msg.msg_control = NULL;
4667 msg.msg_controllen = 0;
4668 msg.msg_namelen = 0;
4669 msg.msg_iocb = NULL;
4670 msg.msg_flags = 0;
4671
4672 flags = req->sr_msg.msg_flags;
4673 if (flags & MSG_DONTWAIT)
4674 req->flags |= REQ_F_NOWAIT;
4675 else if (force_nonblock)
4676 flags |= MSG_DONTWAIT;
4677
4678 ret = sock_recvmsg(sock, &msg, flags);
4679 if (force_nonblock && ret == -EAGAIN)
4680 return -EAGAIN;
4681 if (ret == -ERESTARTSYS)
4682 ret = -EINTR;
4683out_free:
4684 if (req->flags & REQ_F_BUFFER_SELECTED)
4685 cflags = io_put_recv_kbuf(req);
4686 if (ret < 0)
4687 req_set_fail_links(req);
4688 __io_req_complete(req, ret, cflags, cs);
4689 return 0;
4690}
4691
4692static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4693{
4694 struct io_accept *accept = &req->accept;
4695
4696 if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
4697 return -EINVAL;
4698 if (sqe->ioprio || sqe->len || sqe->buf_index)
4699 return -EINVAL;
4700
4701 accept->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
4702 accept->addr_len = u64_to_user_ptr(READ_ONCE(sqe->addr2));
4703 accept->flags = READ_ONCE(sqe->accept_flags);
4704 accept->nofile = rlimit(RLIMIT_NOFILE);
4705 return 0;
4706}
4707
4708static int io_accept(struct io_kiocb *req, bool force_nonblock,
4709 struct io_comp_state *cs)
4710{
4711 struct io_accept *accept = &req->accept;
4712 unsigned int file_flags = force_nonblock ? O_NONBLOCK : 0;
4713 int ret;
4714
4715 if (req->file->f_flags & O_NONBLOCK)
4716 req->flags |= REQ_F_NOWAIT;
4717
4718 ret = __sys_accept4_file(req->file, file_flags, accept->addr,
4719 accept->addr_len, accept->flags,
4720 accept->nofile);
4721 if (ret == -EAGAIN && force_nonblock)
4722 return -EAGAIN;
4723 if (ret < 0) {
4724 if (ret == -ERESTARTSYS)
4725 ret = -EINTR;
4726 req_set_fail_links(req);
4727 }
4728 __io_req_complete(req, ret, 0, cs);
4729 return 0;
4730}
4731
4732static int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4733{
4734 struct io_connect *conn = &req->connect;
4735 struct io_async_connect *io = req->async_data;
4736
4737 if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
4738 return -EINVAL;
4739 if (sqe->ioprio || sqe->len || sqe->buf_index || sqe->rw_flags)
4740 return -EINVAL;
4741
4742 conn->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
4743 conn->addr_len = READ_ONCE(sqe->addr2);
4744
4745 if (!io)
4746 return 0;
4747
4748 return move_addr_to_kernel(conn->addr, conn->addr_len,
4749 &io->address);
4750}
4751
4752static int io_connect(struct io_kiocb *req, bool force_nonblock,
4753 struct io_comp_state *cs)
4754{
4755 struct io_async_connect __io, *io;
4756 unsigned file_flags;
4757 int ret;
4758
4759 if (req->async_data) {
4760 io = req->async_data;
4761 } else {
4762 ret = move_addr_to_kernel(req->connect.addr,
4763 req->connect.addr_len,
4764 &__io.address);
4765 if (ret)
4766 goto out;
4767 io = &__io;
4768 }
4769
4770 file_flags = force_nonblock ? O_NONBLOCK : 0;
4771
4772 ret = __sys_connect_file(req->file, &io->address,
4773 req->connect.addr_len, file_flags);
4774 if ((ret == -EAGAIN || ret == -EINPROGRESS) && force_nonblock) {
4775 if (req->async_data)
4776 return -EAGAIN;
4777 if (io_alloc_async_data(req)) {
4778 ret = -ENOMEM;
4779 goto out;
4780 }
4781 io = req->async_data;
4782 memcpy(req->async_data, &__io, sizeof(__io));
4783 return -EAGAIN;
4784 }
4785 if (ret == -ERESTARTSYS)
4786 ret = -EINTR;
4787out:
4788 if (ret < 0)
4789 req_set_fail_links(req);
4790 __io_req_complete(req, ret, 0, cs);
4791 return 0;
4792}
4793#else /* !CONFIG_NET */
4794static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4795{
4796 return -EOPNOTSUPP;
4797}
4798
4799static int io_sendmsg(struct io_kiocb *req, bool force_nonblock,
4800 struct io_comp_state *cs)
4801{
4802 return -EOPNOTSUPP;
4803}
4804
4805static int io_send(struct io_kiocb *req, bool force_nonblock,
4806 struct io_comp_state *cs)
4807{
4808 return -EOPNOTSUPP;
4809}
4810
4811static int io_recvmsg_prep(struct io_kiocb *req,
4812 const struct io_uring_sqe *sqe)
4813{
4814 return -EOPNOTSUPP;
4815}
4816
4817static int io_recvmsg(struct io_kiocb *req, bool force_nonblock,
4818 struct io_comp_state *cs)
4819{
4820 return -EOPNOTSUPP;
4821}
4822
4823static int io_recv(struct io_kiocb *req, bool force_nonblock,
4824 struct io_comp_state *cs)
4825{
4826 return -EOPNOTSUPP;
4827}
4828
4829static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4830{
4831 return -EOPNOTSUPP;
4832}
4833
4834static int io_accept(struct io_kiocb *req, bool force_nonblock,
4835 struct io_comp_state *cs)
4836{
4837 return -EOPNOTSUPP;
4838}
4839
4840static int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
4841{
4842 return -EOPNOTSUPP;
4843}
4844
4845static int io_connect(struct io_kiocb *req, bool force_nonblock,
4846 struct io_comp_state *cs)
4847{
4848 return -EOPNOTSUPP;
4849}
4850#endif /* CONFIG_NET */
4851
4852struct io_poll_table {
4853 struct poll_table_struct pt;
4854 struct io_kiocb *req;
4855 int error;
4856};
4857
4858static int __io_async_wake(struct io_kiocb *req, struct io_poll_iocb *poll,
4859 __poll_t mask, task_work_func_t func)
4860{
4861 bool twa_signal_ok;
4862 int ret;
4863
4864 /* for instances that support it check for an event match first: */
4865 if (mask && !(mask & poll->events))
4866 return 0;
4867
4868 trace_io_uring_task_add(req->ctx, req->opcode, req->user_data, mask);
4869
4870 list_del_init(&poll->wait.entry);
4871
4872 req->result = mask;
4873 init_task_work(&req->task_work, func);
4874 percpu_ref_get(&req->ctx->refs);
4875
4876 /*
4877 * If we using the signalfd wait_queue_head for this wakeup, then
4878 * it's not safe to use TWA_SIGNAL as we could be recursing on the
4879 * tsk->sighand->siglock on doing the wakeup. Should not be needed
4880 * either, as the normal wakeup will suffice.
4881 */
4882 twa_signal_ok = (poll->head != &req->task->sighand->signalfd_wqh);
4883
4884 /*
4885 * If this fails, then the task is exiting. When a task exits, the
4886 * work gets canceled, so just cancel this request as well instead
4887 * of executing it. We can't safely execute it anyway, as we may not
4888 * have the needed state needed for it anyway.
4889 */
4890 ret = io_req_task_work_add(req, twa_signal_ok);
4891 if (unlikely(ret)) {
4892 struct task_struct *tsk;
4893
4894 WRITE_ONCE(poll->canceled, true);
4895 tsk = io_wq_get_task(req->ctx->io_wq);
4896 task_work_add(tsk, &req->task_work, TWA_NONE);
4897 wake_up_process(tsk);
4898 }
4899 return 1;
4900}
4901
4902static bool io_poll_rewait(struct io_kiocb *req, struct io_poll_iocb *poll)
4903 __acquires(&req->ctx->completion_lock)
4904{
4905 struct io_ring_ctx *ctx = req->ctx;
4906
4907 if (!req->result && !READ_ONCE(poll->canceled)) {
4908 struct poll_table_struct pt = { ._key = poll->events };
4909
4910 req->result = vfs_poll(req->file, &pt) & poll->events;
4911 }
4912
4913 spin_lock_irq(&ctx->completion_lock);
4914 if (!req->result && !READ_ONCE(poll->canceled)) {
4915 add_wait_queue(poll->head, &poll->wait);
4916 return true;
4917 }
4918
4919 return false;
4920}
4921
4922static struct io_poll_iocb *io_poll_get_double(struct io_kiocb *req)
4923{
4924 /* pure poll stashes this in ->async_data, poll driven retry elsewhere */
4925 if (req->opcode == IORING_OP_POLL_ADD)
4926 return req->async_data;
4927 return req->apoll->double_poll;
4928}
4929
4930static struct io_poll_iocb *io_poll_get_single(struct io_kiocb *req)
4931{
4932 if (req->opcode == IORING_OP_POLL_ADD)
4933 return &req->poll;
4934 return &req->apoll->poll;
4935}
4936
4937static void io_poll_remove_double(struct io_kiocb *req)
4938{
4939 struct io_poll_iocb *poll = io_poll_get_double(req);
4940
4941 lockdep_assert_held(&req->ctx->completion_lock);
4942
4943 if (poll && poll->head) {
4944 struct wait_queue_head *head = poll->head;
4945
4946 spin_lock(&head->lock);
4947 list_del_init(&poll->wait.entry);
4948 if (poll->wait.private)
4949 refcount_dec(&req->refs);
4950 poll->head = NULL;
4951 spin_unlock(&head->lock);
4952 }
4953}
4954
4955static void io_poll_complete(struct io_kiocb *req, __poll_t mask, int error)
4956{
4957 struct io_ring_ctx *ctx = req->ctx;
4958
4959 io_poll_remove_double(req);
4960 req->poll.done = true;
4961 io_cqring_fill_event(req, error ? error : mangle_poll(mask));
4962 io_commit_cqring(ctx);
4963}
4964
4965static void io_poll_task_func(struct callback_head *cb)
4966{
4967 struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
4968 struct io_ring_ctx *ctx = req->ctx;
4969 struct io_kiocb *nxt;
4970
4971 if (io_poll_rewait(req, &req->poll)) {
4972 spin_unlock_irq(&ctx->completion_lock);
4973 } else {
4974 hash_del(&req->hash_node);
4975 io_poll_complete(req, req->result, 0);
4976 spin_unlock_irq(&ctx->completion_lock);
4977
4978 nxt = io_put_req_find_next(req);
4979 io_cqring_ev_posted(ctx);
4980 if (nxt)
4981 __io_req_task_submit(nxt);
4982 }
4983
4984 percpu_ref_put(&ctx->refs);
4985}
4986
4987static int io_poll_double_wake(struct wait_queue_entry *wait, unsigned mode,
4988 int sync, void *key)
4989{
4990 struct io_kiocb *req = wait->private;
4991 struct io_poll_iocb *poll = io_poll_get_single(req);
4992 __poll_t mask = key_to_poll(key);
4993
4994 /* for instances that support it check for an event match first: */
4995 if (mask && !(mask & poll->events))
4996 return 0;
4997
4998 list_del_init(&wait->entry);
4999
5000 if (poll && poll->head) {
5001 bool done;
5002
5003 spin_lock(&poll->head->lock);
5004 done = list_empty(&poll->wait.entry);
5005 if (!done)
5006 list_del_init(&poll->wait.entry);
5007 /* make sure double remove sees this as being gone */
5008 wait->private = NULL;
5009 spin_unlock(&poll->head->lock);
5010 if (!done) {
5011 /* use wait func handler, so it matches the rq type */
5012 poll->wait.func(&poll->wait, mode, sync, key);
5013 }
5014 }
5015 refcount_dec(&req->refs);
5016 return 1;
5017}
5018
5019static void io_init_poll_iocb(struct io_poll_iocb *poll, __poll_t events,
5020 wait_queue_func_t wake_func)
5021{
5022 poll->head = NULL;
5023 poll->done = false;
5024 poll->canceled = false;
5025 poll->events = events;
5026 INIT_LIST_HEAD(&poll->wait.entry);
5027 init_waitqueue_func_entry(&poll->wait, wake_func);
5028}
5029
5030static void __io_queue_proc(struct io_poll_iocb *poll, struct io_poll_table *pt,
5031 struct wait_queue_head *head,
5032 struct io_poll_iocb **poll_ptr)
5033{
5034 struct io_kiocb *req = pt->req;
5035
5036 /*
5037 * If poll->head is already set, it's because the file being polled
5038 * uses multiple waitqueues for poll handling (eg one for read, one
5039 * for write). Setup a separate io_poll_iocb if this happens.
5040 */
5041 if (unlikely(poll->head)) {
5042 struct io_poll_iocb *poll_one = poll;
5043
5044 /* already have a 2nd entry, fail a third attempt */
5045 if (*poll_ptr) {
5046 pt->error = -EINVAL;
5047 return;
5048 }
5049 poll = kmalloc(sizeof(*poll), GFP_ATOMIC);
5050 if (!poll) {
5051 pt->error = -ENOMEM;
5052 return;
5053 }
5054 io_init_poll_iocb(poll, poll_one->events, io_poll_double_wake);
5055 refcount_inc(&req->refs);
5056 poll->wait.private = req;
5057 *poll_ptr = poll;
5058 }
5059
5060 pt->error = 0;
5061 poll->head = head;
5062
5063 if (poll->events & EPOLLEXCLUSIVE)
5064 add_wait_queue_exclusive(head, &poll->wait);
5065 else
5066 add_wait_queue(head, &poll->wait);
5067}
5068
5069static void io_async_queue_proc(struct file *file, struct wait_queue_head *head,
5070 struct poll_table_struct *p)
5071{
5072 struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
5073 struct async_poll *apoll = pt->req->apoll;
5074
5075 __io_queue_proc(&apoll->poll, pt, head, &apoll->double_poll);
5076}
5077
5078static void io_async_task_func(struct callback_head *cb)
5079{
5080 struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
5081 struct async_poll *apoll = req->apoll;
5082 struct io_ring_ctx *ctx = req->ctx;
5083
5084 trace_io_uring_task_run(req->ctx, req->opcode, req->user_data);
5085
5086 if (io_poll_rewait(req, &apoll->poll)) {
5087 spin_unlock_irq(&ctx->completion_lock);
5088 percpu_ref_put(&ctx->refs);
5089 return;
5090 }
5091
5092 /* If req is still hashed, it cannot have been canceled. Don't check. */
5093 if (hash_hashed(&req->hash_node))
5094 hash_del(&req->hash_node);
5095
5096 io_poll_remove_double(req);
5097 spin_unlock_irq(&ctx->completion_lock);
5098
5099 if (!READ_ONCE(apoll->poll.canceled))
5100 __io_req_task_submit(req);
5101 else
5102 __io_req_task_cancel(req, -ECANCELED);
5103
5104 percpu_ref_put(&ctx->refs);
5105 kfree(apoll->double_poll);
5106 kfree(apoll);
5107}
5108
5109static int io_async_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
5110 void *key)
5111{
5112 struct io_kiocb *req = wait->private;
5113 struct io_poll_iocb *poll = &req->apoll->poll;
5114
5115 trace_io_uring_poll_wake(req->ctx, req->opcode, req->user_data,
5116 key_to_poll(key));
5117
5118 return __io_async_wake(req, poll, key_to_poll(key), io_async_task_func);
5119}
5120
5121static void io_poll_req_insert(struct io_kiocb *req)
5122{
5123 struct io_ring_ctx *ctx = req->ctx;
5124 struct hlist_head *list;
5125
5126 list = &ctx->cancel_hash[hash_long(req->user_data, ctx->cancel_hash_bits)];
5127 hlist_add_head(&req->hash_node, list);
5128}
5129
5130static __poll_t __io_arm_poll_handler(struct io_kiocb *req,
5131 struct io_poll_iocb *poll,
5132 struct io_poll_table *ipt, __poll_t mask,
5133 wait_queue_func_t wake_func)
5134 __acquires(&ctx->completion_lock)
5135{
5136 struct io_ring_ctx *ctx = req->ctx;
5137 bool cancel = false;
5138
5139 INIT_HLIST_NODE(&req->hash_node);
5140 io_init_poll_iocb(poll, mask, wake_func);
5141 poll->file = req->file;
5142 poll->wait.private = req;
5143
5144 ipt->pt._key = mask;
5145 ipt->req = req;
5146 ipt->error = -EINVAL;
5147
5148 mask = vfs_poll(req->file, &ipt->pt) & poll->events;
5149
5150 spin_lock_irq(&ctx->completion_lock);
5151 if (likely(poll->head)) {
5152 spin_lock(&poll->head->lock);
5153 if (unlikely(list_empty(&poll->wait.entry))) {
5154 if (ipt->error)
5155 cancel = true;
5156 ipt->error = 0;
5157 mask = 0;
5158 }
5159 if (mask || ipt->error)
5160 list_del_init(&poll->wait.entry);
5161 else if (cancel)
5162 WRITE_ONCE(poll->canceled, true);
5163 else if (!poll->done) /* actually waiting for an event */
5164 io_poll_req_insert(req);
5165 spin_unlock(&poll->head->lock);
5166 }
5167
5168 return mask;
5169}
5170
5171static bool io_arm_poll_handler(struct io_kiocb *req)
5172{
5173 const struct io_op_def *def = &io_op_defs[req->opcode];
5174 struct io_ring_ctx *ctx = req->ctx;
5175 struct async_poll *apoll;
5176 struct io_poll_table ipt;
5177 __poll_t mask, ret;
5178 int rw;
5179
5180 if (!req->file || !file_can_poll(req->file))
5181 return false;
5182 if (req->flags & REQ_F_POLLED)
5183 return false;
5184 if (def->pollin)
5185 rw = READ;
5186 else if (def->pollout)
5187 rw = WRITE;
5188 else
5189 return false;
5190 /* if we can't nonblock try, then no point in arming a poll handler */
5191 if (!io_file_supports_async(req->file, rw))
5192 return false;
5193
5194 apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
5195 if (unlikely(!apoll))
5196 return false;
5197 apoll->double_poll = NULL;
5198
5199 req->flags |= REQ_F_POLLED;
5200 req->apoll = apoll;
5201
5202 mask = 0;
5203 if (def->pollin)
5204 mask |= POLLIN | POLLRDNORM;
5205 if (def->pollout)
5206 mask |= POLLOUT | POLLWRNORM;
5207
5208 /* If reading from MSG_ERRQUEUE using recvmsg, ignore POLLIN */
5209 if ((req->opcode == IORING_OP_RECVMSG) &&
5210 (req->sr_msg.msg_flags & MSG_ERRQUEUE))
5211 mask &= ~POLLIN;
5212
5213 mask |= POLLERR | POLLPRI;
5214
5215 ipt.pt._qproc = io_async_queue_proc;
5216
5217 ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask,
5218 io_async_wake);
5219 if (ret || ipt.error) {
5220 io_poll_remove_double(req);
5221 spin_unlock_irq(&ctx->completion_lock);
5222 kfree(apoll->double_poll);
5223 kfree(apoll);
5224 return false;
5225 }
5226 spin_unlock_irq(&ctx->completion_lock);
5227 trace_io_uring_poll_arm(ctx, req->opcode, req->user_data, mask,
5228 apoll->poll.events);
5229 return true;
5230}
5231
5232static bool __io_poll_remove_one(struct io_kiocb *req,
5233 struct io_poll_iocb *poll)
5234{
5235 bool do_complete = false;
5236
5237 spin_lock(&poll->head->lock);
5238 WRITE_ONCE(poll->canceled, true);
5239 if (!list_empty(&poll->wait.entry)) {
5240 list_del_init(&poll->wait.entry);
5241 do_complete = true;
5242 }
5243 spin_unlock(&poll->head->lock);
5244 hash_del(&req->hash_node);
5245 return do_complete;
5246}
5247
5248static bool io_poll_remove_one(struct io_kiocb *req)
5249{
5250 bool do_complete;
5251
5252 io_poll_remove_double(req);
5253
5254 if (req->opcode == IORING_OP_POLL_ADD) {
5255 do_complete = __io_poll_remove_one(req, &req->poll);
5256 } else {
5257 struct async_poll *apoll = req->apoll;
5258
5259 /* non-poll requests have submit ref still */
5260 do_complete = __io_poll_remove_one(req, &apoll->poll);
5261 if (do_complete) {
5262 io_put_req(req);
5263 kfree(apoll->double_poll);
5264 kfree(apoll);
5265 }
5266 }
5267
5268 if (do_complete) {
5269 io_cqring_fill_event(req, -ECANCELED);
5270 io_commit_cqring(req->ctx);
5271 req_set_fail_links(req);
5272 io_put_req_deferred(req, 1);
5273 }
5274
5275 return do_complete;
5276}
5277
5278/*
5279 * Returns true if we found and killed one or more poll requests
5280 */
5281static bool io_poll_remove_all(struct io_ring_ctx *ctx, struct task_struct *tsk)
5282{
5283 struct hlist_node *tmp;
5284 struct io_kiocb *req;
5285 int posted = 0, i;
5286
5287 spin_lock_irq(&ctx->completion_lock);
5288 for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
5289 struct hlist_head *list;
5290
5291 list = &ctx->cancel_hash[i];
5292 hlist_for_each_entry_safe(req, tmp, list, hash_node) {
5293 if (io_task_match(req, tsk))
5294 posted += io_poll_remove_one(req);
5295 }
5296 }
5297 spin_unlock_irq(&ctx->completion_lock);
5298
5299 if (posted)
5300 io_cqring_ev_posted(ctx);
5301
5302 return posted != 0;
5303}
5304
5305static int io_poll_cancel(struct io_ring_ctx *ctx, __u64 sqe_addr)
5306{
5307 struct hlist_head *list;
5308 struct io_kiocb *req;
5309
5310 list = &ctx->cancel_hash[hash_long(sqe_addr, ctx->cancel_hash_bits)];
5311 hlist_for_each_entry(req, list, hash_node) {
5312 if (sqe_addr != req->user_data)
5313 continue;
5314 if (io_poll_remove_one(req))
5315 return 0;
5316 return -EALREADY;
5317 }
5318
5319 return -ENOENT;
5320}
5321
5322static int io_poll_remove_prep(struct io_kiocb *req,
5323 const struct io_uring_sqe *sqe)
5324{
5325 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
5326 return -EINVAL;
5327 if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index ||
5328 sqe->poll_events)
5329 return -EINVAL;
5330
5331 req->poll.addr = READ_ONCE(sqe->addr);
5332 return 0;
5333}
5334
5335/*
5336 * Find a running poll command that matches one specified in sqe->addr,
5337 * and remove it if found.
5338 */
5339static int io_poll_remove(struct io_kiocb *req)
5340{
5341 struct io_ring_ctx *ctx = req->ctx;
5342 u64 addr;
5343 int ret;
5344
5345 addr = req->poll.addr;
5346 spin_lock_irq(&ctx->completion_lock);
5347 ret = io_poll_cancel(ctx, addr);
5348 spin_unlock_irq(&ctx->completion_lock);
5349
5350 if (ret < 0)
5351 req_set_fail_links(req);
5352 io_req_complete(req, ret);
5353 return 0;
5354}
5355
5356static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
5357 void *key)
5358{
5359 struct io_kiocb *req = wait->private;
5360 struct io_poll_iocb *poll = &req->poll;
5361
5362 return __io_async_wake(req, poll, key_to_poll(key), io_poll_task_func);
5363}
5364
5365static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head,
5366 struct poll_table_struct *p)
5367{
5368 struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
5369
5370 __io_queue_proc(&pt->req->poll, pt, head, (struct io_poll_iocb **) &pt->req->async_data);
5371}
5372
5373static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
5374{
5375 struct io_poll_iocb *poll = &req->poll;
5376 u32 events;
5377
5378 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
5379 return -EINVAL;
5380 if (sqe->addr || sqe->ioprio || sqe->off || sqe->len || sqe->buf_index)
5381 return -EINVAL;
5382
5383 events = READ_ONCE(sqe->poll32_events);
5384#ifdef __BIG_ENDIAN
5385 events = swahw32(events);
5386#endif
5387 poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP |
5388 (events & EPOLLEXCLUSIVE);
5389 return 0;
5390}
5391
5392static int io_poll_add(struct io_kiocb *req)
5393{
5394 struct io_poll_iocb *poll = &req->poll;
5395 struct io_ring_ctx *ctx = req->ctx;
5396 struct io_poll_table ipt;
5397 __poll_t mask;
5398
5399 ipt.pt._qproc = io_poll_queue_proc;
5400
5401 mask = __io_arm_poll_handler(req, &req->poll, &ipt, poll->events,
5402 io_poll_wake);
5403
5404 if (mask) { /* no async, we'd stolen it */
5405 ipt.error = 0;
5406 io_poll_complete(req, mask, 0);
5407 }
5408 spin_unlock_irq(&ctx->completion_lock);
5409
5410 if (mask) {
5411 io_cqring_ev_posted(ctx);
5412 io_put_req(req);
5413 }
5414 return ipt.error;
5415}
5416
5417static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
5418{
5419 struct io_timeout_data *data = container_of(timer,
5420 struct io_timeout_data, timer);
5421 struct io_kiocb *req = data->req;
5422 struct io_ring_ctx *ctx = req->ctx;
5423 unsigned long flags;
5424
5425 spin_lock_irqsave(&ctx->completion_lock, flags);
5426 list_del_init(&req->timeout.list);
5427 atomic_set(&req->ctx->cq_timeouts,
5428 atomic_read(&req->ctx->cq_timeouts) + 1);
5429
5430 io_cqring_fill_event(req, -ETIME);
5431 io_commit_cqring(ctx);
5432 spin_unlock_irqrestore(&ctx->completion_lock, flags);
5433
5434 io_cqring_ev_posted(ctx);
5435 req_set_fail_links(req);
5436 io_put_req(req);
5437 return HRTIMER_NORESTART;
5438}
5439
5440static int __io_timeout_cancel(struct io_kiocb *req)
5441{
5442 struct io_timeout_data *io = req->async_data;
5443 int ret;
5444
5445 ret = hrtimer_try_to_cancel(&io->timer);
5446 if (ret == -1)
5447 return -EALREADY;
5448 list_del_init(&req->timeout.list);
5449
5450 req_set_fail_links(req);
5451 io_cqring_fill_event(req, -ECANCELED);
5452 io_put_req_deferred(req, 1);
5453 return 0;
5454}
5455
5456static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data)
5457{
5458 struct io_kiocb *req;
5459 int ret = -ENOENT;
5460
5461 list_for_each_entry(req, &ctx->timeout_list, timeout.list) {
5462 if (user_data == req->user_data) {
5463 ret = 0;
5464 break;
5465 }
5466 }
5467
5468 if (ret == -ENOENT)
5469 return ret;
5470
5471 return __io_timeout_cancel(req);
5472}
5473
5474static int io_timeout_remove_prep(struct io_kiocb *req,
5475 const struct io_uring_sqe *sqe)
5476{
5477 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
5478 return -EINVAL;
5479 if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
5480 return -EINVAL;
5481 if (sqe->ioprio || sqe->buf_index || sqe->len || sqe->timeout_flags)
5482 return -EINVAL;
5483
5484 req->timeout_rem.addr = READ_ONCE(sqe->addr);
5485 return 0;
5486}
5487
5488/*
5489 * Remove or update an existing timeout command
5490 */
5491static int io_timeout_remove(struct io_kiocb *req)
5492{
5493 struct io_ring_ctx *ctx = req->ctx;
5494 int ret;
5495
5496 spin_lock_irq(&ctx->completion_lock);
5497 ret = io_timeout_cancel(ctx, req->timeout_rem.addr);
5498
5499 io_cqring_fill_event(req, ret);
5500 io_commit_cqring(ctx);
5501 spin_unlock_irq(&ctx->completion_lock);
5502 io_cqring_ev_posted(ctx);
5503 if (ret < 0)
5504 req_set_fail_links(req);
5505 io_put_req(req);
5506 return 0;
5507}
5508
5509static int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
5510 bool is_timeout_link)
5511{
5512 struct io_timeout_data *data;
5513 unsigned flags;
5514 u32 off = READ_ONCE(sqe->off);
5515
5516 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
5517 return -EINVAL;
5518 if (sqe->ioprio || sqe->buf_index || sqe->len != 1)
5519 return -EINVAL;
5520 if (off && is_timeout_link)
5521 return -EINVAL;
5522 flags = READ_ONCE(sqe->timeout_flags);
5523 if (flags & ~IORING_TIMEOUT_ABS)
5524 return -EINVAL;
5525
5526 req->timeout.off = off;
5527
5528 if (!req->async_data && io_alloc_async_data(req))
5529 return -ENOMEM;
5530
5531 data = req->async_data;
5532 data->req = req;
5533
5534 if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr)))
5535 return -EFAULT;
5536
5537 if (flags & IORING_TIMEOUT_ABS)
5538 data->mode = HRTIMER_MODE_ABS;
5539 else
5540 data->mode = HRTIMER_MODE_REL;
5541
5542 hrtimer_init(&data->timer, CLOCK_MONOTONIC, data->mode);
5543 return 0;
5544}
5545
5546static int io_timeout(struct io_kiocb *req)
5547{
5548 struct io_ring_ctx *ctx = req->ctx;
5549 struct io_timeout_data *data = req->async_data;
5550 struct list_head *entry;
5551 u32 tail, off = req->timeout.off;
5552
5553 spin_lock_irq(&ctx->completion_lock);
5554
5555 /*
5556 * sqe->off holds how many events that need to occur for this
5557 * timeout event to be satisfied. If it isn't set, then this is
5558 * a pure timeout request, sequence isn't used.
5559 */
5560 if (io_is_timeout_noseq(req)) {
5561 entry = ctx->timeout_list.prev;
5562 goto add;
5563 }
5564
5565 tail = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts);
5566 req->timeout.target_seq = tail + off;
5567
5568 /*
5569 * Insertion sort, ensuring the first entry in the list is always
5570 * the one we need first.
5571 */
5572 list_for_each_prev(entry, &ctx->timeout_list) {
5573 struct io_kiocb *nxt = list_entry(entry, struct io_kiocb,
5574 timeout.list);
5575
5576 if (io_is_timeout_noseq(nxt))
5577 continue;
5578 /* nxt.seq is behind @tail, otherwise would've been completed */
5579 if (off >= nxt->timeout.target_seq - tail)
5580 break;
5581 }
5582add:
5583 list_add(&req->timeout.list, entry);
5584 data->timer.function = io_timeout_fn;
5585 hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode);
5586 spin_unlock_irq(&ctx->completion_lock);
5587 return 0;
5588}
5589
5590static bool io_cancel_cb(struct io_wq_work *work, void *data)
5591{
5592 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
5593
5594 return req->user_data == (unsigned long) data;
5595}
5596
5597static int io_async_cancel_one(struct io_ring_ctx *ctx, void *sqe_addr)
5598{
5599 enum io_wq_cancel cancel_ret;
5600 int ret = 0;
5601
5602 cancel_ret = io_wq_cancel_cb(ctx->io_wq, io_cancel_cb, sqe_addr, false);
5603 switch (cancel_ret) {
5604 case IO_WQ_CANCEL_OK:
5605 ret = 0;
5606 break;
5607 case IO_WQ_CANCEL_RUNNING:
5608 ret = -EALREADY;
5609 break;
5610 case IO_WQ_CANCEL_NOTFOUND:
5611 ret = -ENOENT;
5612 break;
5613 }
5614
5615 return ret;
5616}
5617
5618static void io_async_find_and_cancel(struct io_ring_ctx *ctx,
5619 struct io_kiocb *req, __u64 sqe_addr,
5620 int success_ret)
5621{
5622 unsigned long flags;
5623 int ret;
5624
5625 ret = io_async_cancel_one(ctx, (void *) (unsigned long) sqe_addr);
5626 if (ret != -ENOENT) {
5627 spin_lock_irqsave(&ctx->completion_lock, flags);
5628 goto done;
5629 }
5630
5631 spin_lock_irqsave(&ctx->completion_lock, flags);
5632 ret = io_timeout_cancel(ctx, sqe_addr);
5633 if (ret != -ENOENT)
5634 goto done;
5635 ret = io_poll_cancel(ctx, sqe_addr);
5636done:
5637 if (!ret)
5638 ret = success_ret;
5639 io_cqring_fill_event(req, ret);
5640 io_commit_cqring(ctx);
5641 spin_unlock_irqrestore(&ctx->completion_lock, flags);
5642 io_cqring_ev_posted(ctx);
5643
5644 if (ret < 0)
5645 req_set_fail_links(req);
5646 io_put_req(req);
5647}
5648
5649static int io_async_cancel_prep(struct io_kiocb *req,
5650 const struct io_uring_sqe *sqe)
5651{
5652 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
5653 return -EINVAL;
5654 if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
5655 return -EINVAL;
5656 if (sqe->ioprio || sqe->off || sqe->len || sqe->cancel_flags)
5657 return -EINVAL;
5658
5659 req->cancel.addr = READ_ONCE(sqe->addr);
5660 return 0;
5661}
5662
5663static int io_async_cancel(struct io_kiocb *req)
5664{
5665 struct io_ring_ctx *ctx = req->ctx;
5666
5667 io_async_find_and_cancel(ctx, req, req->cancel.addr, 0);
5668 return 0;
5669}
5670
5671static int io_files_update_prep(struct io_kiocb *req,
5672 const struct io_uring_sqe *sqe)
5673{
5674 if (unlikely(req->ctx->flags & IORING_SETUP_SQPOLL))
5675 return -EINVAL;
5676 if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
5677 return -EINVAL;
5678 if (sqe->ioprio || sqe->rw_flags)
5679 return -EINVAL;
5680
5681 req->files_update.offset = READ_ONCE(sqe->off);
5682 req->files_update.nr_args = READ_ONCE(sqe->len);
5683 if (!req->files_update.nr_args)
5684 return -EINVAL;
5685 req->files_update.arg = READ_ONCE(sqe->addr);
5686 return 0;
5687}
5688
5689static int io_files_update(struct io_kiocb *req, bool force_nonblock,
5690 struct io_comp_state *cs)
5691{
5692 struct io_ring_ctx *ctx = req->ctx;
5693 struct io_uring_files_update up;
5694 int ret;
5695
5696 if (force_nonblock)
5697 return -EAGAIN;
5698
5699 up.offset = req->files_update.offset;
5700 up.fds = req->files_update.arg;
5701
5702 mutex_lock(&ctx->uring_lock);
5703 ret = __io_sqe_files_update(ctx, &up, req->files_update.nr_args);
5704 mutex_unlock(&ctx->uring_lock);
5705
5706 if (ret < 0)
5707 req_set_fail_links(req);
5708 __io_req_complete(req, ret, 0, cs);
5709 return 0;
5710}
5711
5712static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
5713{
5714 switch (req->opcode) {
5715 case IORING_OP_NOP:
5716 return 0;
5717 case IORING_OP_READV:
5718 case IORING_OP_READ_FIXED:
5719 case IORING_OP_READ:
5720 return io_read_prep(req, sqe);
5721 case IORING_OP_WRITEV:
5722 case IORING_OP_WRITE_FIXED:
5723 case IORING_OP_WRITE:
5724 return io_write_prep(req, sqe);
5725 case IORING_OP_POLL_ADD:
5726 return io_poll_add_prep(req, sqe);
5727 case IORING_OP_POLL_REMOVE:
5728 return io_poll_remove_prep(req, sqe);
5729 case IORING_OP_FSYNC:
5730 return io_prep_fsync(req, sqe);
5731 case IORING_OP_SYNC_FILE_RANGE:
5732 return io_prep_sfr(req, sqe);
5733 case IORING_OP_SENDMSG:
5734 case IORING_OP_SEND:
5735 return io_sendmsg_prep(req, sqe);
5736 case IORING_OP_RECVMSG:
5737 case IORING_OP_RECV:
5738 return io_recvmsg_prep(req, sqe);
5739 case IORING_OP_CONNECT:
5740 return io_connect_prep(req, sqe);
5741 case IORING_OP_TIMEOUT:
5742 return io_timeout_prep(req, sqe, false);
5743 case IORING_OP_TIMEOUT_REMOVE:
5744 return io_timeout_remove_prep(req, sqe);
5745 case IORING_OP_ASYNC_CANCEL:
5746 return io_async_cancel_prep(req, sqe);
5747 case IORING_OP_LINK_TIMEOUT:
5748 return io_timeout_prep(req, sqe, true);
5749 case IORING_OP_ACCEPT:
5750 return io_accept_prep(req, sqe);
5751 case IORING_OP_FALLOCATE:
5752 return io_fallocate_prep(req, sqe);
5753 case IORING_OP_OPENAT:
5754 return io_openat_prep(req, sqe);
5755 case IORING_OP_CLOSE:
5756 return io_close_prep(req, sqe);
5757 case IORING_OP_FILES_UPDATE:
5758 return io_files_update_prep(req, sqe);
5759 case IORING_OP_STATX:
5760 return io_statx_prep(req, sqe);
5761 case IORING_OP_FADVISE:
5762 return io_fadvise_prep(req, sqe);
5763 case IORING_OP_MADVISE:
5764 return io_madvise_prep(req, sqe);
5765 case IORING_OP_OPENAT2:
5766 return io_openat2_prep(req, sqe);
5767 case IORING_OP_EPOLL_CTL:
5768 return io_epoll_ctl_prep(req, sqe);
5769 case IORING_OP_SPLICE:
5770 return io_splice_prep(req, sqe);
5771 case IORING_OP_PROVIDE_BUFFERS:
5772 return io_provide_buffers_prep(req, sqe);
5773 case IORING_OP_REMOVE_BUFFERS:
5774 return io_remove_buffers_prep(req, sqe);
5775 case IORING_OP_TEE:
5776 return io_tee_prep(req, sqe);
5777 }
5778
5779 printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
5780 req->opcode);
5781 return-EINVAL;
5782}
5783
5784static int io_req_defer_prep(struct io_kiocb *req,
5785 const struct io_uring_sqe *sqe)
5786{
5787 if (!sqe)
5788 return 0;
5789 if (io_alloc_async_data(req))
5790 return -EAGAIN;
5791 return io_req_prep(req, sqe);
5792}
5793
5794static u32 io_get_sequence(struct io_kiocb *req)
5795{
5796 struct io_kiocb *pos;
5797 struct io_ring_ctx *ctx = req->ctx;
5798 u32 total_submitted, nr_reqs = 1;
5799
5800 if (req->flags & REQ_F_LINK_HEAD)
5801 list_for_each_entry(pos, &req->link_list, link_list)
5802 nr_reqs++;
5803
5804 total_submitted = ctx->cached_sq_head - ctx->cached_sq_dropped;
5805 return total_submitted - nr_reqs;
5806}
5807
5808static int io_req_defer(struct io_kiocb *req, const struct io_uring_sqe *sqe)
5809{
5810 struct io_ring_ctx *ctx = req->ctx;
5811 struct io_defer_entry *de;
5812 int ret;
5813 u32 seq;
5814
5815 /* Still need defer if there is pending req in defer list. */
5816 if (likely(list_empty_careful(&ctx->defer_list) &&
5817 !(req->flags & REQ_F_IO_DRAIN)))
5818 return 0;
5819
5820 seq = io_get_sequence(req);
5821 /* Still a chance to pass the sequence check */
5822 if (!req_need_defer(req, seq) && list_empty_careful(&ctx->defer_list))
5823 return 0;
5824
5825 if (!req->async_data) {
5826 ret = io_req_defer_prep(req, sqe);
5827 if (ret)
5828 return ret;
5829 }
5830 io_prep_async_link(req);
5831 de = kmalloc(sizeof(*de), GFP_KERNEL);
5832 if (!de)
5833 return -ENOMEM;
5834
5835 spin_lock_irq(&ctx->completion_lock);
5836 if (!req_need_defer(req, seq) && list_empty(&ctx->defer_list)) {
5837 spin_unlock_irq(&ctx->completion_lock);
5838 kfree(de);
5839 io_queue_async_work(req);
5840 return -EIOCBQUEUED;
5841 }
5842
5843 trace_io_uring_defer(ctx, req, req->user_data);
5844 de->req = req;
5845 de->seq = seq;
5846 list_add_tail(&de->list, &ctx->defer_list);
5847 spin_unlock_irq(&ctx->completion_lock);
5848 return -EIOCBQUEUED;
5849}
5850
5851static void io_req_drop_files(struct io_kiocb *req)
5852{
5853 struct io_ring_ctx *ctx = req->ctx;
5854 unsigned long flags;
5855
5856 spin_lock_irqsave(&ctx->inflight_lock, flags);
5857 list_del(&req->inflight_entry);
5858 if (waitqueue_active(&ctx->inflight_wait))
5859 wake_up(&ctx->inflight_wait);
5860 spin_unlock_irqrestore(&ctx->inflight_lock, flags);
5861 req->flags &= ~REQ_F_INFLIGHT;
5862 put_files_struct(req->work.identity->files);
5863 put_nsproxy(req->work.identity->nsproxy);
5864 req->work.flags &= ~IO_WQ_WORK_FILES;
5865}
5866
5867static void __io_clean_op(struct io_kiocb *req)
5868{
5869 if (req->flags & REQ_F_BUFFER_SELECTED) {
5870 switch (req->opcode) {
5871 case IORING_OP_READV:
5872 case IORING_OP_READ_FIXED:
5873 case IORING_OP_READ:
5874 kfree((void *)(unsigned long)req->rw.addr);
5875 break;
5876 case IORING_OP_RECVMSG:
5877 case IORING_OP_RECV:
5878 kfree(req->sr_msg.kbuf);
5879 break;
5880 }
5881 req->flags &= ~REQ_F_BUFFER_SELECTED;
5882 }
5883
5884 if (req->flags & REQ_F_NEED_CLEANUP) {
5885 switch (req->opcode) {
5886 case IORING_OP_READV:
5887 case IORING_OP_READ_FIXED:
5888 case IORING_OP_READ:
5889 case IORING_OP_WRITEV:
5890 case IORING_OP_WRITE_FIXED:
5891 case IORING_OP_WRITE: {
5892 struct io_async_rw *io = req->async_data;
5893 if (io->free_iovec)
5894 kfree(io->free_iovec);
5895 break;
5896 }
5897 case IORING_OP_RECVMSG:
5898 case IORING_OP_SENDMSG: {
5899 struct io_async_msghdr *io = req->async_data;
5900 if (io->iov != io->fast_iov)
5901 kfree(io->iov);
5902 break;
5903 }
5904 case IORING_OP_SPLICE:
5905 case IORING_OP_TEE:
5906 io_put_file(req, req->splice.file_in,
5907 (req->splice.flags & SPLICE_F_FD_IN_FIXED));
5908 break;
5909 case IORING_OP_OPENAT:
5910 case IORING_OP_OPENAT2:
5911 if (req->open.filename)
5912 putname(req->open.filename);
5913 break;
5914 }
5915 req->flags &= ~REQ_F_NEED_CLEANUP;
5916 }
5917
5918 if (req->flags & REQ_F_INFLIGHT)
5919 io_req_drop_files(req);
5920}
5921
5922static int io_issue_sqe(struct io_kiocb *req, bool force_nonblock,
5923 struct io_comp_state *cs)
5924{
5925 struct io_ring_ctx *ctx = req->ctx;
5926 int ret;
5927
5928 switch (req->opcode) {
5929 case IORING_OP_NOP:
5930 ret = io_nop(req, cs);
5931 break;
5932 case IORING_OP_READV:
5933 case IORING_OP_READ_FIXED:
5934 case IORING_OP_READ:
5935 ret = io_read(req, force_nonblock, cs);
5936 break;
5937 case IORING_OP_WRITEV:
5938 case IORING_OP_WRITE_FIXED:
5939 case IORING_OP_WRITE:
5940 ret = io_write(req, force_nonblock, cs);
5941 break;
5942 case IORING_OP_FSYNC:
5943 ret = io_fsync(req, force_nonblock);
5944 break;
5945 case IORING_OP_POLL_ADD:
5946 ret = io_poll_add(req);
5947 break;
5948 case IORING_OP_POLL_REMOVE:
5949 ret = io_poll_remove(req);
5950 break;
5951 case IORING_OP_SYNC_FILE_RANGE:
5952 ret = io_sync_file_range(req, force_nonblock);
5953 break;
5954 case IORING_OP_SENDMSG:
5955 ret = io_sendmsg(req, force_nonblock, cs);
5956 break;
5957 case IORING_OP_SEND:
5958 ret = io_send(req, force_nonblock, cs);
5959 break;
5960 case IORING_OP_RECVMSG:
5961 ret = io_recvmsg(req, force_nonblock, cs);
5962 break;
5963 case IORING_OP_RECV:
5964 ret = io_recv(req, force_nonblock, cs);
5965 break;
5966 case IORING_OP_TIMEOUT:
5967 ret = io_timeout(req);
5968 break;
5969 case IORING_OP_TIMEOUT_REMOVE:
5970 ret = io_timeout_remove(req);
5971 break;
5972 case IORING_OP_ACCEPT:
5973 ret = io_accept(req, force_nonblock, cs);
5974 break;
5975 case IORING_OP_CONNECT:
5976 ret = io_connect(req, force_nonblock, cs);
5977 break;
5978 case IORING_OP_ASYNC_CANCEL:
5979 ret = io_async_cancel(req);
5980 break;
5981 case IORING_OP_FALLOCATE:
5982 ret = io_fallocate(req, force_nonblock);
5983 break;
5984 case IORING_OP_OPENAT:
5985 ret = io_openat(req, force_nonblock);
5986 break;
5987 case IORING_OP_CLOSE:
5988 ret = io_close(req, force_nonblock, cs);
5989 break;
5990 case IORING_OP_FILES_UPDATE:
5991 ret = io_files_update(req, force_nonblock, cs);
5992 break;
5993 case IORING_OP_STATX:
5994 ret = io_statx(req, force_nonblock);
5995 break;
5996 case IORING_OP_FADVISE:
5997 ret = io_fadvise(req, force_nonblock);
5998 break;
5999 case IORING_OP_MADVISE:
6000 ret = io_madvise(req, force_nonblock);
6001 break;
6002 case IORING_OP_OPENAT2:
6003 ret = io_openat2(req, force_nonblock);
6004 break;
6005 case IORING_OP_EPOLL_CTL:
6006 ret = io_epoll_ctl(req, force_nonblock, cs);
6007 break;
6008 case IORING_OP_SPLICE:
6009 ret = io_splice(req, force_nonblock);
6010 break;
6011 case IORING_OP_PROVIDE_BUFFERS:
6012 ret = io_provide_buffers(req, force_nonblock, cs);
6013 break;
6014 case IORING_OP_REMOVE_BUFFERS:
6015 ret = io_remove_buffers(req, force_nonblock, cs);
6016 break;
6017 case IORING_OP_TEE:
6018 ret = io_tee(req, force_nonblock);
6019 break;
6020 default:
6021 ret = -EINVAL;
6022 break;
6023 }
6024
6025 if (ret)
6026 return ret;
6027
6028 /* If the op doesn't have a file, we're not polling for it */
6029 if ((ctx->flags & IORING_SETUP_IOPOLL) && req->file) {
6030 const bool in_async = io_wq_current_is_worker();
6031
6032 /* workqueue context doesn't hold uring_lock, grab it now */
6033 if (in_async)
6034 mutex_lock(&ctx->uring_lock);
6035
6036 io_iopoll_req_issued(req);
6037
6038 if (in_async)
6039 mutex_unlock(&ctx->uring_lock);
6040 }
6041
6042 return 0;
6043}
6044
6045static struct io_wq_work *io_wq_submit_work(struct io_wq_work *work)
6046{
6047 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
6048 struct io_kiocb *timeout;
6049 int ret = 0;
6050
6051 timeout = io_prep_linked_timeout(req);
6052 if (timeout)
6053 io_queue_linked_timeout(timeout);
6054
6055 /* if NO_CANCEL is set, we must still run the work */
6056 if ((work->flags & (IO_WQ_WORK_CANCEL|IO_WQ_WORK_NO_CANCEL)) ==
6057 IO_WQ_WORK_CANCEL) {
6058 ret = -ECANCELED;
6059 }
6060
6061 if (!ret) {
6062 do {
6063 ret = io_issue_sqe(req, false, NULL);
6064 /*
6065 * We can get EAGAIN for polled IO even though we're
6066 * forcing a sync submission from here, since we can't
6067 * wait for request slots on the block side.
6068 */
6069 if (ret != -EAGAIN)
6070 break;
6071 cond_resched();
6072 } while (1);
6073 }
6074
6075 if (ret) {
6076 req_set_fail_links(req);
6077 io_req_complete(req, ret);
6078 }
6079
6080 return io_steal_work(req);
6081}
6082
6083static inline struct file *io_file_from_index(struct io_ring_ctx *ctx,
6084 int index)
6085{
6086 struct fixed_file_table *table;
6087
6088 table = &ctx->file_data->table[index >> IORING_FILE_TABLE_SHIFT];
6089 return table->files[index & IORING_FILE_TABLE_MASK];
6090}
6091
6092static struct file *io_file_get(struct io_submit_state *state,
6093 struct io_kiocb *req, int fd, bool fixed)
6094{
6095 struct io_ring_ctx *ctx = req->ctx;
6096 struct file *file;
6097
6098 if (fixed) {
6099 if (unlikely((unsigned int)fd >= ctx->nr_user_files))
6100 return NULL;
6101 fd = array_index_nospec(fd, ctx->nr_user_files);
6102 file = io_file_from_index(ctx, fd);
6103 if (file) {
6104 req->fixed_file_refs = &ctx->file_data->node->refs;
6105 percpu_ref_get(req->fixed_file_refs);
6106 }
6107 } else {
6108 trace_io_uring_file_get(ctx, fd);
6109 file = __io_file_get(state, fd);
6110 }
6111
6112 return file;
6113}
6114
6115static int io_req_set_file(struct io_submit_state *state, struct io_kiocb *req,
6116 int fd)
6117{
6118 bool fixed;
6119
6120 fixed = (req->flags & REQ_F_FIXED_FILE) != 0;
6121 if (unlikely(!fixed && io_async_submit(req->ctx)))
6122 return -EBADF;
6123
6124 req->file = io_file_get(state, req, fd, fixed);
6125 if (req->file || io_op_defs[req->opcode].needs_file_no_error)
6126 return 0;
6127 return -EBADF;
6128}
6129
6130static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer)
6131{
6132 struct io_timeout_data *data = container_of(timer,
6133 struct io_timeout_data, timer);
6134 struct io_kiocb *req = data->req;
6135 struct io_ring_ctx *ctx = req->ctx;
6136 struct io_kiocb *prev = NULL;
6137 unsigned long flags;
6138
6139 spin_lock_irqsave(&ctx->completion_lock, flags);
6140
6141 /*
6142 * We don't expect the list to be empty, that will only happen if we
6143 * race with the completion of the linked work.
6144 */
6145 if (!list_empty(&req->link_list)) {
6146 prev = list_entry(req->link_list.prev, struct io_kiocb,
6147 link_list);
6148 if (refcount_inc_not_zero(&prev->refs))
6149 list_del_init(&req->link_list);
6150 else
6151 prev = NULL;
6152 }
6153
6154 spin_unlock_irqrestore(&ctx->completion_lock, flags);
6155
6156 if (prev) {
6157 req_set_fail_links(prev);
6158 io_async_find_and_cancel(ctx, req, prev->user_data, -ETIME);
6159 io_put_req(prev);
6160 } else {
6161 io_req_complete(req, -ETIME);
6162 }
6163 return HRTIMER_NORESTART;
6164}
6165
6166static void __io_queue_linked_timeout(struct io_kiocb *req)
6167{
6168 /*
6169 * If the list is now empty, then our linked request finished before
6170 * we got a chance to setup the timer
6171 */
6172 if (!list_empty(&req->link_list)) {
6173 struct io_timeout_data *data = req->async_data;
6174
6175 data->timer.function = io_link_timeout_fn;
6176 hrtimer_start(&data->timer, timespec64_to_ktime(data->ts),
6177 data->mode);
6178 }
6179}
6180
6181static void io_queue_linked_timeout(struct io_kiocb *req)
6182{
6183 struct io_ring_ctx *ctx = req->ctx;
6184
6185 spin_lock_irq(&ctx->completion_lock);
6186 __io_queue_linked_timeout(req);
6187 spin_unlock_irq(&ctx->completion_lock);
6188
6189 /* drop submission reference */
6190 io_put_req(req);
6191}
6192
6193static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
6194{
6195 struct io_kiocb *nxt;
6196
6197 if (!(req->flags & REQ_F_LINK_HEAD))
6198 return NULL;
6199 if (req->flags & REQ_F_LINK_TIMEOUT)
6200 return NULL;
6201
6202 nxt = list_first_entry_or_null(&req->link_list, struct io_kiocb,
6203 link_list);
6204 if (!nxt || nxt->opcode != IORING_OP_LINK_TIMEOUT)
6205 return NULL;
6206
6207 nxt->flags |= REQ_F_LTIMEOUT_ACTIVE;
6208 req->flags |= REQ_F_LINK_TIMEOUT;
6209 return nxt;
6210}
6211
6212static void __io_queue_sqe(struct io_kiocb *req, struct io_comp_state *cs)
6213{
6214 struct io_kiocb *linked_timeout;
6215 const struct cred *old_creds = NULL;
6216 int ret;
6217
6218again:
6219 linked_timeout = io_prep_linked_timeout(req);
6220
6221 if ((req->flags & REQ_F_WORK_INITIALIZED) &&
6222 (req->work.flags & IO_WQ_WORK_CREDS) &&
6223 req->work.identity->creds != current_cred()) {
6224 if (old_creds)
6225 revert_creds(old_creds);
6226 if (old_creds == req->work.identity->creds)
6227 old_creds = NULL; /* restored original creds */
6228 else
6229 old_creds = override_creds(req->work.identity->creds);
6230 }
6231
6232 ret = io_issue_sqe(req, true, cs);
6233
6234 /*
6235 * We async punt it if the file wasn't marked NOWAIT, or if the file
6236 * doesn't support non-blocking read/write attempts
6237 */
6238 if (ret == -EAGAIN && !(req->flags & REQ_F_NOWAIT)) {
6239 if (!io_arm_poll_handler(req)) {
6240 /*
6241 * Queued up for async execution, worker will release
6242 * submit reference when the iocb is actually submitted.
6243 */
6244 io_queue_async_work(req);
6245 }
6246
6247 if (linked_timeout)
6248 io_queue_linked_timeout(linked_timeout);
6249 } else if (likely(!ret)) {
6250 /* drop submission reference */
6251 req = io_put_req_find_next(req);
6252 if (linked_timeout)
6253 io_queue_linked_timeout(linked_timeout);
6254
6255 if (req) {
6256 if (!(req->flags & REQ_F_FORCE_ASYNC))
6257 goto again;
6258 io_queue_async_work(req);
6259 }
6260 } else {
6261 /* un-prep timeout, so it'll be killed as any other linked */
6262 req->flags &= ~REQ_F_LINK_TIMEOUT;
6263 req_set_fail_links(req);
6264 io_put_req(req);
6265 io_req_complete(req, ret);
6266 }
6267
6268 if (old_creds)
6269 revert_creds(old_creds);
6270}
6271
6272static void io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
6273 struct io_comp_state *cs)
6274{
6275 int ret;
6276
6277 ret = io_req_defer(req, sqe);
6278 if (ret) {
6279 if (ret != -EIOCBQUEUED) {
6280fail_req:
6281 req_set_fail_links(req);
6282 io_put_req(req);
6283 io_req_complete(req, ret);
6284 }
6285 } else if (req->flags & REQ_F_FORCE_ASYNC) {
6286 if (!req->async_data) {
6287 ret = io_req_defer_prep(req, sqe);
6288 if (unlikely(ret))
6289 goto fail_req;
6290 }
6291 io_queue_async_work(req);
6292 } else {
6293 if (sqe) {
6294 ret = io_req_prep(req, sqe);
6295 if (unlikely(ret))
6296 goto fail_req;
6297 }
6298 __io_queue_sqe(req, cs);
6299 }
6300}
6301
6302static inline void io_queue_link_head(struct io_kiocb *req,
6303 struct io_comp_state *cs)
6304{
6305 if (unlikely(req->flags & REQ_F_FAIL_LINK)) {
6306 io_put_req(req);
6307 io_req_complete(req, -ECANCELED);
6308 } else
6309 io_queue_sqe(req, NULL, cs);
6310}
6311
6312static int io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
6313 struct io_kiocb **link, struct io_comp_state *cs)
6314{
6315 struct io_ring_ctx *ctx = req->ctx;
6316 int ret;
6317
6318 /*
6319 * If we already have a head request, queue this one for async
6320 * submittal once the head completes. If we don't have a head but
6321 * IOSQE_IO_LINK is set in the sqe, start a new head. This one will be
6322 * submitted sync once the chain is complete. If none of those
6323 * conditions are true (normal request), then just queue it.
6324 */
6325 if (*link) {
6326 struct io_kiocb *head = *link;
6327
6328 /*
6329 * Taking sequential execution of a link, draining both sides
6330 * of the link also fullfils IOSQE_IO_DRAIN semantics for all
6331 * requests in the link. So, it drains the head and the
6332 * next after the link request. The last one is done via
6333 * drain_next flag to persist the effect across calls.
6334 */
6335 if (req->flags & REQ_F_IO_DRAIN) {
6336 head->flags |= REQ_F_IO_DRAIN;
6337 ctx->drain_next = 1;
6338 }
6339 ret = io_req_defer_prep(req, sqe);
6340 if (unlikely(ret)) {
6341 /* fail even hard links since we don't submit */
6342 head->flags |= REQ_F_FAIL_LINK;
6343 return ret;
6344 }
6345 trace_io_uring_link(ctx, req, head);
6346 list_add_tail(&req->link_list, &head->link_list);
6347
6348 /* last request of a link, enqueue the link */
6349 if (!(req->flags & (REQ_F_LINK | REQ_F_HARDLINK))) {
6350 io_queue_link_head(head, cs);
6351 *link = NULL;
6352 }
6353 } else {
6354 if (unlikely(ctx->drain_next)) {
6355 req->flags |= REQ_F_IO_DRAIN;
6356 ctx->drain_next = 0;
6357 }
6358 if (req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) {
6359 req->flags |= REQ_F_LINK_HEAD;
6360 INIT_LIST_HEAD(&req->link_list);
6361
6362 ret = io_req_defer_prep(req, sqe);
6363 if (unlikely(ret))
6364 req->flags |= REQ_F_FAIL_LINK;
6365 *link = req;
6366 } else {
6367 io_queue_sqe(req, sqe, cs);
6368 }
6369 }
6370
6371 return 0;
6372}
6373
6374/*
6375 * Batched submission is done, ensure local IO is flushed out.
6376 */
6377static void io_submit_state_end(struct io_submit_state *state)
6378{
6379 if (!list_empty(&state->comp.list))
6380 io_submit_flush_completions(&state->comp);
6381 blk_finish_plug(&state->plug);
6382 io_state_file_put(state);
6383 if (state->free_reqs)
6384 kmem_cache_free_bulk(req_cachep, state->free_reqs, state->reqs);
6385}
6386
6387/*
6388 * Start submission side cache.
6389 */
6390static void io_submit_state_start(struct io_submit_state *state,
6391 struct io_ring_ctx *ctx, unsigned int max_ios)
6392{
6393 blk_start_plug(&state->plug);
6394 state->comp.nr = 0;
6395 INIT_LIST_HEAD(&state->comp.list);
6396 state->comp.ctx = ctx;
6397 state->free_reqs = 0;
6398 state->file = NULL;
6399 state->ios_left = max_ios;
6400}
6401
6402static void io_commit_sqring(struct io_ring_ctx *ctx)
6403{
6404 struct io_rings *rings = ctx->rings;
6405
6406 /*
6407 * Ensure any loads from the SQEs are done at this point,
6408 * since once we write the new head, the application could
6409 * write new data to them.
6410 */
6411 smp_store_release(&rings->sq.head, ctx->cached_sq_head);
6412}
6413
6414/*
6415 * Fetch an sqe, if one is available. Note that sqe_ptr will point to memory
6416 * that is mapped by userspace. This means that care needs to be taken to
6417 * ensure that reads are stable, as we cannot rely on userspace always
6418 * being a good citizen. If members of the sqe are validated and then later
6419 * used, it's important that those reads are done through READ_ONCE() to
6420 * prevent a re-load down the line.
6421 */
6422static const struct io_uring_sqe *io_get_sqe(struct io_ring_ctx *ctx)
6423{
6424 u32 *sq_array = ctx->sq_array;
6425 unsigned head;
6426
6427 /*
6428 * The cached sq head (or cq tail) serves two purposes:
6429 *
6430 * 1) allows us to batch the cost of updating the user visible
6431 * head updates.
6432 * 2) allows the kernel side to track the head on its own, even
6433 * though the application is the one updating it.
6434 */
6435 head = READ_ONCE(sq_array[ctx->cached_sq_head & ctx->sq_mask]);
6436 if (likely(head < ctx->sq_entries))
6437 return &ctx->sq_sqes[head];
6438
6439 /* drop invalid entries */
6440 ctx->cached_sq_dropped++;
6441 WRITE_ONCE(ctx->rings->sq_dropped, ctx->cached_sq_dropped);
6442 return NULL;
6443}
6444
6445static inline void io_consume_sqe(struct io_ring_ctx *ctx)
6446{
6447 ctx->cached_sq_head++;
6448}
6449
6450/*
6451 * Check SQE restrictions (opcode and flags).
6452 *
6453 * Returns 'true' if SQE is allowed, 'false' otherwise.
6454 */
6455static inline bool io_check_restriction(struct io_ring_ctx *ctx,
6456 struct io_kiocb *req,
6457 unsigned int sqe_flags)
6458{
6459 if (!ctx->restricted)
6460 return true;
6461
6462 if (!test_bit(req->opcode, ctx->restrictions.sqe_op))
6463 return false;
6464
6465 if ((sqe_flags & ctx->restrictions.sqe_flags_required) !=
6466 ctx->restrictions.sqe_flags_required)
6467 return false;
6468
6469 if (sqe_flags & ~(ctx->restrictions.sqe_flags_allowed |
6470 ctx->restrictions.sqe_flags_required))
6471 return false;
6472
6473 return true;
6474}
6475
6476#define SQE_VALID_FLAGS (IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK| \
6477 IOSQE_IO_HARDLINK | IOSQE_ASYNC | \
6478 IOSQE_BUFFER_SELECT)
6479
6480static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
6481 const struct io_uring_sqe *sqe,
6482 struct io_submit_state *state)
6483{
6484 unsigned int sqe_flags;
6485 int id, ret;
6486
6487 req->opcode = READ_ONCE(sqe->opcode);
6488 req->user_data = READ_ONCE(sqe->user_data);
6489 req->async_data = NULL;
6490 req->file = NULL;
6491 req->ctx = ctx;
6492 req->flags = 0;
6493 /* one is dropped after submission, the other at completion */
6494 refcount_set(&req->refs, 2);
6495 req->task = current;
6496 req->result = 0;
6497
6498 if (unlikely(req->opcode >= IORING_OP_LAST))
6499 return -EINVAL;
6500
6501 if (unlikely(io_sq_thread_acquire_mm(ctx, req)))
6502 return -EFAULT;
6503
6504 sqe_flags = READ_ONCE(sqe->flags);
6505 /* enforce forwards compatibility on users */
6506 if (unlikely(sqe_flags & ~SQE_VALID_FLAGS))
6507 return -EINVAL;
6508
6509 if (unlikely(!io_check_restriction(ctx, req, sqe_flags)))
6510 return -EACCES;
6511
6512 if ((sqe_flags & IOSQE_BUFFER_SELECT) &&
6513 !io_op_defs[req->opcode].buffer_select)
6514 return -EOPNOTSUPP;
6515
6516 id = READ_ONCE(sqe->personality);
6517 if (id) {
6518 struct io_identity *iod;
6519
6520 iod = idr_find(&ctx->personality_idr, id);
6521 if (unlikely(!iod))
6522 return -EINVAL;
6523 refcount_inc(&iod->count);
6524
6525 __io_req_init_async(req);
6526 get_cred(iod->creds);
6527 req->work.identity = iod;
6528 req->work.flags |= IO_WQ_WORK_CREDS;
6529 }
6530
6531 /* same numerical values with corresponding REQ_F_*, safe to copy */
6532 req->flags |= sqe_flags;
6533
6534 if (!io_op_defs[req->opcode].needs_file)
6535 return 0;
6536
6537 ret = io_req_set_file(state, req, READ_ONCE(sqe->fd));
6538 state->ios_left--;
6539 return ret;
6540}
6541
6542static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr)
6543{
6544 struct io_submit_state state;
6545 struct io_kiocb *link = NULL;
6546 int i, submitted = 0;
6547
6548 /* if we have a backlog and couldn't flush it all, return BUSY */
6549 if (test_bit(0, &ctx->sq_check_overflow)) {
6550 if (!list_empty(&ctx->cq_overflow_list) &&
6551 !io_cqring_overflow_flush(ctx, false, NULL, NULL))
6552 return -EBUSY;
6553 }
6554
6555 /* make sure SQ entry isn't read before tail */
6556 nr = min3(nr, ctx->sq_entries, io_sqring_entries(ctx));
6557
6558 if (!percpu_ref_tryget_many(&ctx->refs, nr))
6559 return -EAGAIN;
6560
6561 percpu_counter_add(&current->io_uring->inflight, nr);
6562 refcount_add(nr, &current->usage);
6563
6564 io_submit_state_start(&state, ctx, nr);
6565
6566 for (i = 0; i < nr; i++) {
6567 const struct io_uring_sqe *sqe;
6568 struct io_kiocb *req;
6569 int err;
6570
6571 sqe = io_get_sqe(ctx);
6572 if (unlikely(!sqe)) {
6573 io_consume_sqe(ctx);
6574 break;
6575 }
6576 req = io_alloc_req(ctx, &state);
6577 if (unlikely(!req)) {
6578 if (!submitted)
6579 submitted = -EAGAIN;
6580 break;
6581 }
6582 io_consume_sqe(ctx);
6583 /* will complete beyond this point, count as submitted */
6584 submitted++;
6585
6586 err = io_init_req(ctx, req, sqe, &state);
6587 if (unlikely(err)) {
6588fail_req:
6589 io_put_req(req);
6590 io_req_complete(req, err);
6591 break;
6592 }
6593
6594 trace_io_uring_submit_sqe(ctx, req->opcode, req->user_data,
6595 true, io_async_submit(ctx));
6596 err = io_submit_sqe(req, sqe, &link, &state.comp);
6597 if (err)
6598 goto fail_req;
6599 }
6600
6601 if (unlikely(submitted != nr)) {
6602 int ref_used = (submitted == -EAGAIN) ? 0 : submitted;
6603 struct io_uring_task *tctx = current->io_uring;
6604 int unused = nr - ref_used;
6605
6606 percpu_ref_put_many(&ctx->refs, unused);
6607 percpu_counter_sub(&tctx->inflight, unused);
6608 put_task_struct_many(current, unused);
6609 }
6610 if (link)
6611 io_queue_link_head(link, &state.comp);
6612 io_submit_state_end(&state);
6613
6614 /* Commit SQ ring head once we've consumed and submitted all SQEs */
6615 io_commit_sqring(ctx);
6616
6617 return submitted;
6618}
6619
6620static inline void io_ring_set_wakeup_flag(struct io_ring_ctx *ctx)
6621{
6622 /* Tell userspace we may need a wakeup call */
6623 spin_lock_irq(&ctx->completion_lock);
6624 ctx->rings->sq_flags |= IORING_SQ_NEED_WAKEUP;
6625 spin_unlock_irq(&ctx->completion_lock);
6626}
6627
6628static inline void io_ring_clear_wakeup_flag(struct io_ring_ctx *ctx)
6629{
6630 spin_lock_irq(&ctx->completion_lock);
6631 ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
6632 spin_unlock_irq(&ctx->completion_lock);
6633}
6634
6635static int io_sq_wake_function(struct wait_queue_entry *wqe, unsigned mode,
6636 int sync, void *key)
6637{
6638 struct io_ring_ctx *ctx = container_of(wqe, struct io_ring_ctx, sqo_wait_entry);
6639 int ret;
6640
6641 ret = autoremove_wake_function(wqe, mode, sync, key);
6642 if (ret) {
6643 unsigned long flags;
6644
6645 spin_lock_irqsave(&ctx->completion_lock, flags);
6646 ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
6647 spin_unlock_irqrestore(&ctx->completion_lock, flags);
6648 }
6649 return ret;
6650}
6651
6652enum sq_ret {
6653 SQT_IDLE = 1,
6654 SQT_SPIN = 2,
6655 SQT_DID_WORK = 4,
6656};
6657
6658static enum sq_ret __io_sq_thread(struct io_ring_ctx *ctx,
6659 unsigned long start_jiffies, bool cap_entries)
6660{
6661 unsigned long timeout = start_jiffies + ctx->sq_thread_idle;
6662 struct io_sq_data *sqd = ctx->sq_data;
6663 unsigned int to_submit;
6664 int ret = 0;
6665
6666again:
6667 if (!list_empty(&ctx->iopoll_list)) {
6668 unsigned nr_events = 0;
6669
6670 mutex_lock(&ctx->uring_lock);
6671 if (!list_empty(&ctx->iopoll_list) && !need_resched())
6672 io_do_iopoll(ctx, &nr_events, 0);
6673 mutex_unlock(&ctx->uring_lock);
6674 }
6675
6676 to_submit = io_sqring_entries(ctx);
6677
6678 /*
6679 * If submit got -EBUSY, flag us as needing the application
6680 * to enter the kernel to reap and flush events.
6681 */
6682 if (!to_submit || ret == -EBUSY || need_resched()) {
6683 /*
6684 * Drop cur_mm before scheduling, we can't hold it for
6685 * long periods (or over schedule()). Do this before
6686 * adding ourselves to the waitqueue, as the unuse/drop
6687 * may sleep.
6688 */
6689 io_sq_thread_drop_mm();
6690
6691 /*
6692 * We're polling. If we're within the defined idle
6693 * period, then let us spin without work before going
6694 * to sleep. The exception is if we got EBUSY doing
6695 * more IO, we should wait for the application to
6696 * reap events and wake us up.
6697 */
6698 if (!list_empty(&ctx->iopoll_list) || need_resched() ||
6699 (!time_after(jiffies, timeout) && ret != -EBUSY &&
6700 !percpu_ref_is_dying(&ctx->refs)))
6701 return SQT_SPIN;
6702
6703 prepare_to_wait(&sqd->wait, &ctx->sqo_wait_entry,
6704 TASK_INTERRUPTIBLE);
6705
6706 /*
6707 * While doing polled IO, before going to sleep, we need
6708 * to check if there are new reqs added to iopoll_list,
6709 * it is because reqs may have been punted to io worker
6710 * and will be added to iopoll_list later, hence check
6711 * the iopoll_list again.
6712 */
6713 if ((ctx->flags & IORING_SETUP_IOPOLL) &&
6714 !list_empty_careful(&ctx->iopoll_list)) {
6715 finish_wait(&sqd->wait, &ctx->sqo_wait_entry);
6716 goto again;
6717 }
6718
6719 to_submit = io_sqring_entries(ctx);
6720 if (!to_submit || ret == -EBUSY)
6721 return SQT_IDLE;
6722 }
6723
6724 finish_wait(&sqd->wait, &ctx->sqo_wait_entry);
6725 io_ring_clear_wakeup_flag(ctx);
6726
6727 /* if we're handling multiple rings, cap submit size for fairness */
6728 if (cap_entries && to_submit > 8)
6729 to_submit = 8;
6730
6731 mutex_lock(&ctx->uring_lock);
6732 if (likely(!percpu_ref_is_dying(&ctx->refs)))
6733 ret = io_submit_sqes(ctx, to_submit);
6734 mutex_unlock(&ctx->uring_lock);
6735
6736 if (!io_sqring_full(ctx) && wq_has_sleeper(&ctx->sqo_sq_wait))
6737 wake_up(&ctx->sqo_sq_wait);
6738
6739 return SQT_DID_WORK;
6740}
6741
6742static void io_sqd_init_new(struct io_sq_data *sqd)
6743{
6744 struct io_ring_ctx *ctx;
6745
6746 while (!list_empty(&sqd->ctx_new_list)) {
6747 ctx = list_first_entry(&sqd->ctx_new_list, struct io_ring_ctx, sqd_list);
6748 init_wait(&ctx->sqo_wait_entry);
6749 ctx->sqo_wait_entry.func = io_sq_wake_function;
6750 list_move_tail(&ctx->sqd_list, &sqd->ctx_list);
6751 complete(&ctx->sq_thread_comp);
6752 }
6753}
6754
6755static int io_sq_thread(void *data)
6756{
6757 struct cgroup_subsys_state *cur_css = NULL;
6758 const struct cred *old_cred = NULL;
6759 struct io_sq_data *sqd = data;
6760 struct io_ring_ctx *ctx;
6761 unsigned long start_jiffies;
6762
6763 start_jiffies = jiffies;
6764 while (!kthread_should_stop()) {
6765 enum sq_ret ret = 0;
6766 bool cap_entries;
6767
6768 /*
6769 * Any changes to the sqd lists are synchronized through the
6770 * kthread parking. This synchronizes the thread vs users,
6771 * the users are synchronized on the sqd->ctx_lock.
6772 */
6773 if (kthread_should_park())
6774 kthread_parkme();
6775
6776 if (unlikely(!list_empty(&sqd->ctx_new_list)))
6777 io_sqd_init_new(sqd);
6778
6779 cap_entries = !list_is_singular(&sqd->ctx_list);
6780
6781 list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
6782 if (current->cred != ctx->creds) {
6783 if (old_cred)
6784 revert_creds(old_cred);
6785 old_cred = override_creds(ctx->creds);
6786 }
6787 io_sq_thread_associate_blkcg(ctx, &cur_css);
6788#ifdef CONFIG_AUDIT
6789 current->loginuid = ctx->loginuid;
6790 current->sessionid = ctx->sessionid;
6791#endif
6792
6793 ret |= __io_sq_thread(ctx, start_jiffies, cap_entries);
6794
6795 io_sq_thread_drop_mm();
6796 }
6797
6798 if (ret & SQT_SPIN) {
6799 io_run_task_work();
6800 cond_resched();
6801 } else if (ret == SQT_IDLE) {
6802 if (kthread_should_park())
6803 continue;
6804 list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
6805 io_ring_set_wakeup_flag(ctx);
6806 schedule();
6807 start_jiffies = jiffies;
6808 list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
6809 io_ring_clear_wakeup_flag(ctx);
6810 }
6811 }
6812
6813 io_run_task_work();
6814
6815 if (cur_css)
6816 io_sq_thread_unassociate_blkcg();
6817 if (old_cred)
6818 revert_creds(old_cred);
6819
6820 kthread_parkme();
6821
6822 return 0;
6823}
6824
6825struct io_wait_queue {
6826 struct wait_queue_entry wq;
6827 struct io_ring_ctx *ctx;
6828 unsigned to_wait;
6829 unsigned nr_timeouts;
6830};
6831
6832static inline bool io_should_wake(struct io_wait_queue *iowq, bool noflush)
6833{
6834 struct io_ring_ctx *ctx = iowq->ctx;
6835
6836 /*
6837 * Wake up if we have enough events, or if a timeout occurred since we
6838 * started waiting. For timeouts, we always want to return to userspace,
6839 * regardless of event count.
6840 */
6841 return io_cqring_events(ctx, noflush) >= iowq->to_wait ||
6842 atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
6843}
6844
6845static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode,
6846 int wake_flags, void *key)
6847{
6848 struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue,
6849 wq);
6850
6851 /* use noflush == true, as we can't safely rely on locking context */
6852 if (!io_should_wake(iowq, true))
6853 return -1;
6854
6855 return autoremove_wake_function(curr, mode, wake_flags, key);
6856}
6857
6858static int io_run_task_work_sig(void)
6859{
6860 if (io_run_task_work())
6861 return 1;
6862 if (!signal_pending(current))
6863 return 0;
6864 if (current->jobctl & JOBCTL_TASK_WORK) {
6865 spin_lock_irq(&current->sighand->siglock);
6866 current->jobctl &= ~JOBCTL_TASK_WORK;
6867 recalc_sigpending();
6868 spin_unlock_irq(&current->sighand->siglock);
6869 return 1;
6870 }
6871 return -EINTR;
6872}
6873
6874/*
6875 * Wait until events become available, if we don't already have some. The
6876 * application must reap them itself, as they reside on the shared cq ring.
6877 */
6878static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
6879 const sigset_t __user *sig, size_t sigsz)
6880{
6881 struct io_wait_queue iowq = {
6882 .wq = {
6883 .private = current,
6884 .func = io_wake_function,
6885 .entry = LIST_HEAD_INIT(iowq.wq.entry),
6886 },
6887 .ctx = ctx,
6888 .to_wait = min_events,
6889 };
6890 struct io_rings *rings = ctx->rings;
6891 int ret = 0;
6892
6893 do {
6894 if (io_cqring_events(ctx, false) >= min_events)
6895 return 0;
6896 if (!io_run_task_work())
6897 break;
6898 } while (1);
6899
6900 if (sig) {
6901#ifdef CONFIG_COMPAT
6902 if (in_compat_syscall())
6903 ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig,
6904 sigsz);
6905 else
6906#endif
6907 ret = set_user_sigmask(sig, sigsz);
6908
6909 if (ret)
6910 return ret;
6911 }
6912
6913 iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts);
6914 trace_io_uring_cqring_wait(ctx, min_events);
6915 do {
6916 prepare_to_wait_exclusive(&ctx->wait, &iowq.wq,
6917 TASK_INTERRUPTIBLE);
6918 /* make sure we run task_work before checking for signals */
6919 ret = io_run_task_work_sig();
6920 if (ret > 0)
6921 continue;
6922 else if (ret < 0)
6923 break;
6924 if (io_should_wake(&iowq, false))
6925 break;
6926 schedule();
6927 } while (1);
6928 finish_wait(&ctx->wait, &iowq.wq);
6929
6930 restore_saved_sigmask_unless(ret == -EINTR);
6931
6932 return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0;
6933}
6934
6935static void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
6936{
6937#if defined(CONFIG_UNIX)
6938 if (ctx->ring_sock) {
6939 struct sock *sock = ctx->ring_sock->sk;
6940 struct sk_buff *skb;
6941
6942 while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL)
6943 kfree_skb(skb);
6944 }
6945#else
6946 int i;
6947
6948 for (i = 0; i < ctx->nr_user_files; i++) {
6949 struct file *file;
6950
6951 file = io_file_from_index(ctx, i);
6952 if (file)
6953 fput(file);
6954 }
6955#endif
6956}
6957
6958static void io_file_ref_kill(struct percpu_ref *ref)
6959{
6960 struct fixed_file_data *data;
6961
6962 data = container_of(ref, struct fixed_file_data, refs);
6963 complete(&data->done);
6964}
6965
6966static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
6967{
6968 struct fixed_file_data *data = ctx->file_data;
6969 struct fixed_file_ref_node *ref_node = NULL;
6970 unsigned nr_tables, i;
6971
6972 if (!data)
6973 return -ENXIO;
6974
6975 spin_lock(&data->lock);
6976 ref_node = data->node;
6977 spin_unlock(&data->lock);
6978 if (ref_node)
6979 percpu_ref_kill(&ref_node->refs);
6980
6981 percpu_ref_kill(&data->refs);
6982
6983 /* wait for all refs nodes to complete */
6984 flush_delayed_work(&ctx->file_put_work);
6985 wait_for_completion(&data->done);
6986
6987 __io_sqe_files_unregister(ctx);
6988 nr_tables = DIV_ROUND_UP(ctx->nr_user_files, IORING_MAX_FILES_TABLE);
6989 for (i = 0; i < nr_tables; i++)
6990 kfree(data->table[i].files);
6991 kfree(data->table);
6992 percpu_ref_exit(&data->refs);
6993 kfree(data);
6994 ctx->file_data = NULL;
6995 ctx->nr_user_files = 0;
6996 return 0;
6997}
6998
6999static void io_put_sq_data(struct io_sq_data *sqd)
7000{
7001 if (refcount_dec_and_test(&sqd->refs)) {
7002 /*
7003 * The park is a bit of a work-around, without it we get
7004 * warning spews on shutdown with SQPOLL set and affinity
7005 * set to a single CPU.
7006 */
7007 if (sqd->thread) {
7008 kthread_park(sqd->thread);
7009 kthread_stop(sqd->thread);
7010 }
7011
7012 kfree(sqd);
7013 }
7014}
7015
7016static struct io_sq_data *io_attach_sq_data(struct io_uring_params *p)
7017{
7018 struct io_ring_ctx *ctx_attach;
7019 struct io_sq_data *sqd;
7020 struct fd f;
7021
7022 f = fdget(p->wq_fd);
7023 if (!f.file)
7024 return ERR_PTR(-ENXIO);
7025 if (f.file->f_op != &io_uring_fops) {
7026 fdput(f);
7027 return ERR_PTR(-EINVAL);
7028 }
7029
7030 ctx_attach = f.file->private_data;
7031 sqd = ctx_attach->sq_data;
7032 if (!sqd) {
7033 fdput(f);
7034 return ERR_PTR(-EINVAL);
7035 }
7036
7037 refcount_inc(&sqd->refs);
7038 fdput(f);
7039 return sqd;
7040}
7041
7042static struct io_sq_data *io_get_sq_data(struct io_uring_params *p)
7043{
7044 struct io_sq_data *sqd;
7045
7046 if (p->flags & IORING_SETUP_ATTACH_WQ)
7047 return io_attach_sq_data(p);
7048
7049 sqd = kzalloc(sizeof(*sqd), GFP_KERNEL);
7050 if (!sqd)
7051 return ERR_PTR(-ENOMEM);
7052
7053 refcount_set(&sqd->refs, 1);
7054 INIT_LIST_HEAD(&sqd->ctx_list);
7055 INIT_LIST_HEAD(&sqd->ctx_new_list);
7056 mutex_init(&sqd->ctx_lock);
7057 mutex_init(&sqd->lock);
7058 init_waitqueue_head(&sqd->wait);
7059 return sqd;
7060}
7061
7062static void io_sq_thread_unpark(struct io_sq_data *sqd)
7063 __releases(&sqd->lock)
7064{
7065 if (!sqd->thread)
7066 return;
7067 kthread_unpark(sqd->thread);
7068 mutex_unlock(&sqd->lock);
7069}
7070
7071static void io_sq_thread_park(struct io_sq_data *sqd)
7072 __acquires(&sqd->lock)
7073{
7074 if (!sqd->thread)
7075 return;
7076 mutex_lock(&sqd->lock);
7077 kthread_park(sqd->thread);
7078}
7079
7080static void io_sq_thread_stop(struct io_ring_ctx *ctx)
7081{
7082 struct io_sq_data *sqd = ctx->sq_data;
7083
7084 if (sqd) {
7085 if (sqd->thread) {
7086 /*
7087 * We may arrive here from the error branch in
7088 * io_sq_offload_create() where the kthread is created
7089 * without being waked up, thus wake it up now to make
7090 * sure the wait will complete.
7091 */
7092 wake_up_process(sqd->thread);
7093 wait_for_completion(&ctx->sq_thread_comp);
7094
7095 io_sq_thread_park(sqd);
7096 }
7097
7098 mutex_lock(&sqd->ctx_lock);
7099 list_del(&ctx->sqd_list);
7100 mutex_unlock(&sqd->ctx_lock);
7101
7102 if (sqd->thread) {
7103 finish_wait(&sqd->wait, &ctx->sqo_wait_entry);
7104 io_sq_thread_unpark(sqd);
7105 }
7106
7107 io_put_sq_data(sqd);
7108 ctx->sq_data = NULL;
7109 }
7110}
7111
7112static void io_finish_async(struct io_ring_ctx *ctx)
7113{
7114 io_sq_thread_stop(ctx);
7115
7116 if (ctx->io_wq) {
7117 io_wq_destroy(ctx->io_wq);
7118 ctx->io_wq = NULL;
7119 }
7120}
7121
7122#if defined(CONFIG_UNIX)
7123/*
7124 * Ensure the UNIX gc is aware of our file set, so we are certain that
7125 * the io_uring can be safely unregistered on process exit, even if we have
7126 * loops in the file referencing.
7127 */
7128static int __io_sqe_files_scm(struct io_ring_ctx *ctx, int nr, int offset)
7129{
7130 struct sock *sk = ctx->ring_sock->sk;
7131 struct scm_fp_list *fpl;
7132 struct sk_buff *skb;
7133 int i, nr_files;
7134
7135 fpl = kzalloc(sizeof(*fpl), GFP_KERNEL);
7136 if (!fpl)
7137 return -ENOMEM;
7138
7139 skb = alloc_skb(0, GFP_KERNEL);
7140 if (!skb) {
7141 kfree(fpl);
7142 return -ENOMEM;
7143 }
7144
7145 skb->sk = sk;
7146
7147 nr_files = 0;
7148 fpl->user = get_uid(ctx->user);
7149 for (i = 0; i < nr; i++) {
7150 struct file *file = io_file_from_index(ctx, i + offset);
7151
7152 if (!file)
7153 continue;
7154 fpl->fp[nr_files] = get_file(file);
7155 unix_inflight(fpl->user, fpl->fp[nr_files]);
7156 nr_files++;
7157 }
7158
7159 if (nr_files) {
7160 fpl->max = SCM_MAX_FD;
7161 fpl->count = nr_files;
7162 UNIXCB(skb).fp = fpl;
7163 skb->destructor = unix_destruct_scm;
7164 refcount_add(skb->truesize, &sk->sk_wmem_alloc);
7165 skb_queue_head(&sk->sk_receive_queue, skb);
7166
7167 for (i = 0; i < nr_files; i++)
7168 fput(fpl->fp[i]);
7169 } else {
7170 kfree_skb(skb);
7171 kfree(fpl);
7172 }
7173
7174 return 0;
7175}
7176
7177/*
7178 * If UNIX sockets are enabled, fd passing can cause a reference cycle which
7179 * causes regular reference counting to break down. We rely on the UNIX
7180 * garbage collection to take care of this problem for us.
7181 */
7182static int io_sqe_files_scm(struct io_ring_ctx *ctx)
7183{
7184 unsigned left, total;
7185 int ret = 0;
7186
7187 total = 0;
7188 left = ctx->nr_user_files;
7189 while (left) {
7190 unsigned this_files = min_t(unsigned, left, SCM_MAX_FD);
7191
7192 ret = __io_sqe_files_scm(ctx, this_files, total);
7193 if (ret)
7194 break;
7195 left -= this_files;
7196 total += this_files;
7197 }
7198
7199 if (!ret)
7200 return 0;
7201
7202 while (total < ctx->nr_user_files) {
7203 struct file *file = io_file_from_index(ctx, total);
7204
7205 if (file)
7206 fput(file);
7207 total++;
7208 }
7209
7210 return ret;
7211}
7212#else
7213static int io_sqe_files_scm(struct io_ring_ctx *ctx)
7214{
7215 return 0;
7216}
7217#endif
7218
7219static int io_sqe_alloc_file_tables(struct fixed_file_data *file_data,
7220 unsigned nr_tables, unsigned nr_files)
7221{
7222 int i;
7223
7224 for (i = 0; i < nr_tables; i++) {
7225 struct fixed_file_table *table = &file_data->table[i];
7226 unsigned this_files;
7227
7228 this_files = min(nr_files, IORING_MAX_FILES_TABLE);
7229 table->files = kcalloc(this_files, sizeof(struct file *),
7230 GFP_KERNEL);
7231 if (!table->files)
7232 break;
7233 nr_files -= this_files;
7234 }
7235
7236 if (i == nr_tables)
7237 return 0;
7238
7239 for (i = 0; i < nr_tables; i++) {
7240 struct fixed_file_table *table = &file_data->table[i];
7241 kfree(table->files);
7242 }
7243 return 1;
7244}
7245
7246static void io_ring_file_put(struct io_ring_ctx *ctx, struct file *file)
7247{
7248#if defined(CONFIG_UNIX)
7249 struct sock *sock = ctx->ring_sock->sk;
7250 struct sk_buff_head list, *head = &sock->sk_receive_queue;
7251 struct sk_buff *skb;
7252 int i;
7253
7254 __skb_queue_head_init(&list);
7255
7256 /*
7257 * Find the skb that holds this file in its SCM_RIGHTS. When found,
7258 * remove this entry and rearrange the file array.
7259 */
7260 skb = skb_dequeue(head);
7261 while (skb) {
7262 struct scm_fp_list *fp;
7263
7264 fp = UNIXCB(skb).fp;
7265 for (i = 0; i < fp->count; i++) {
7266 int left;
7267
7268 if (fp->fp[i] != file)
7269 continue;
7270
7271 unix_notinflight(fp->user, fp->fp[i]);
7272 left = fp->count - 1 - i;
7273 if (left) {
7274 memmove(&fp->fp[i], &fp->fp[i + 1],
7275 left * sizeof(struct file *));
7276 }
7277 fp->count--;
7278 if (!fp->count) {
7279 kfree_skb(skb);
7280 skb = NULL;
7281 } else {
7282 __skb_queue_tail(&list, skb);
7283 }
7284 fput(file);
7285 file = NULL;
7286 break;
7287 }
7288
7289 if (!file)
7290 break;
7291
7292 __skb_queue_tail(&list, skb);
7293
7294 skb = skb_dequeue(head);
7295 }
7296
7297 if (skb_peek(&list)) {
7298 spin_lock_irq(&head->lock);
7299 while ((skb = __skb_dequeue(&list)) != NULL)
7300 __skb_queue_tail(head, skb);
7301 spin_unlock_irq(&head->lock);
7302 }
7303#else
7304 fput(file);
7305#endif
7306}
7307
7308struct io_file_put {
7309 struct list_head list;
7310 struct file *file;
7311};
7312
7313static void __io_file_put_work(struct fixed_file_ref_node *ref_node)
7314{
7315 struct fixed_file_data *file_data = ref_node->file_data;
7316 struct io_ring_ctx *ctx = file_data->ctx;
7317 struct io_file_put *pfile, *tmp;
7318
7319 list_for_each_entry_safe(pfile, tmp, &ref_node->file_list, list) {
7320 list_del(&pfile->list);
7321 io_ring_file_put(ctx, pfile->file);
7322 kfree(pfile);
7323 }
7324
7325 percpu_ref_exit(&ref_node->refs);
7326 kfree(ref_node);
7327 percpu_ref_put(&file_data->refs);
7328}
7329
7330static void io_file_put_work(struct work_struct *work)
7331{
7332 struct io_ring_ctx *ctx;
7333 struct llist_node *node;
7334
7335 ctx = container_of(work, struct io_ring_ctx, file_put_work.work);
7336 node = llist_del_all(&ctx->file_put_llist);
7337
7338 while (node) {
7339 struct fixed_file_ref_node *ref_node;
7340 struct llist_node *next = node->next;
7341
7342 ref_node = llist_entry(node, struct fixed_file_ref_node, llist);
7343 __io_file_put_work(ref_node);
7344 node = next;
7345 }
7346}
7347
7348static void io_file_data_ref_zero(struct percpu_ref *ref)
7349{
7350 struct fixed_file_ref_node *ref_node;
7351 struct fixed_file_data *data;
7352 struct io_ring_ctx *ctx;
7353 bool first_add = false;
7354 int delay = HZ;
7355
7356 ref_node = container_of(ref, struct fixed_file_ref_node, refs);
7357 data = ref_node->file_data;
7358 ctx = data->ctx;
7359
7360 spin_lock(&data->lock);
7361 ref_node->done = true;
7362
7363 while (!list_empty(&data->ref_list)) {
7364 ref_node = list_first_entry(&data->ref_list,
7365 struct fixed_file_ref_node, node);
7366 /* recycle ref nodes in order */
7367 if (!ref_node->done)
7368 break;
7369 list_del(&ref_node->node);
7370 first_add |= llist_add(&ref_node->llist, &ctx->file_put_llist);
7371 }
7372 spin_unlock(&data->lock);
7373
7374 if (percpu_ref_is_dying(&data->refs))
7375 delay = 0;
7376
7377 if (!delay)
7378 mod_delayed_work(system_wq, &ctx->file_put_work, 0);
7379 else if (first_add)
7380 queue_delayed_work(system_wq, &ctx->file_put_work, delay);
7381}
7382
7383static struct fixed_file_ref_node *alloc_fixed_file_ref_node(
7384 struct io_ring_ctx *ctx)
7385{
7386 struct fixed_file_ref_node *ref_node;
7387
7388 ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
7389 if (!ref_node)
7390 return ERR_PTR(-ENOMEM);
7391
7392 if (percpu_ref_init(&ref_node->refs, io_file_data_ref_zero,
7393 0, GFP_KERNEL)) {
7394 kfree(ref_node);
7395 return ERR_PTR(-ENOMEM);
7396 }
7397 INIT_LIST_HEAD(&ref_node->node);
7398 INIT_LIST_HEAD(&ref_node->file_list);
7399 ref_node->file_data = ctx->file_data;
7400 ref_node->done = false;
7401 return ref_node;
7402}
7403
7404static void destroy_fixed_file_ref_node(struct fixed_file_ref_node *ref_node)
7405{
7406 percpu_ref_exit(&ref_node->refs);
7407 kfree(ref_node);
7408}
7409
7410static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
7411 unsigned nr_args)
7412{
7413 __s32 __user *fds = (__s32 __user *) arg;
7414 unsigned nr_tables, i;
7415 struct file *file;
7416 int fd, ret = -ENOMEM;
7417 struct fixed_file_ref_node *ref_node;
7418 struct fixed_file_data *file_data;
7419
7420 if (ctx->file_data)
7421 return -EBUSY;
7422 if (!nr_args)
7423 return -EINVAL;
7424 if (nr_args > IORING_MAX_FIXED_FILES)
7425 return -EMFILE;
7426
7427 file_data = kzalloc(sizeof(*ctx->file_data), GFP_KERNEL);
7428 if (!file_data)
7429 return -ENOMEM;
7430 file_data->ctx = ctx;
7431 init_completion(&file_data->done);
7432 INIT_LIST_HEAD(&file_data->ref_list);
7433 spin_lock_init(&file_data->lock);
7434
7435 nr_tables = DIV_ROUND_UP(nr_args, IORING_MAX_FILES_TABLE);
7436 file_data->table = kcalloc(nr_tables, sizeof(*file_data->table),
7437 GFP_KERNEL);
7438 if (!file_data->table)
7439 goto out_free;
7440
7441 if (percpu_ref_init(&file_data->refs, io_file_ref_kill,
7442 PERCPU_REF_ALLOW_REINIT, GFP_KERNEL))
7443 goto out_free;
7444
7445 if (io_sqe_alloc_file_tables(file_data, nr_tables, nr_args))
7446 goto out_ref;
7447 ctx->file_data = file_data;
7448
7449 for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
7450 struct fixed_file_table *table;
7451 unsigned index;
7452
7453 if (copy_from_user(&fd, &fds[i], sizeof(fd))) {
7454 ret = -EFAULT;
7455 goto out_fput;
7456 }
7457 /* allow sparse sets */
7458 if (fd == -1)
7459 continue;
7460
7461 file = fget(fd);
7462 ret = -EBADF;
7463 if (!file)
7464 goto out_fput;
7465
7466 /*
7467 * Don't allow io_uring instances to be registered. If UNIX
7468 * isn't enabled, then this causes a reference cycle and this
7469 * instance can never get freed. If UNIX is enabled we'll
7470 * handle it just fine, but there's still no point in allowing
7471 * a ring fd as it doesn't support regular read/write anyway.
7472 */
7473 if (file->f_op == &io_uring_fops) {
7474 fput(file);
7475 goto out_fput;
7476 }
7477 table = &file_data->table[i >> IORING_FILE_TABLE_SHIFT];
7478 index = i & IORING_FILE_TABLE_MASK;
7479 table->files[index] = file;
7480 }
7481
7482 ret = io_sqe_files_scm(ctx);
7483 if (ret) {
7484 io_sqe_files_unregister(ctx);
7485 return ret;
7486 }
7487
7488 ref_node = alloc_fixed_file_ref_node(ctx);
7489 if (IS_ERR(ref_node)) {
7490 io_sqe_files_unregister(ctx);
7491 return PTR_ERR(ref_node);
7492 }
7493
7494 file_data->node = ref_node;
7495 spin_lock(&file_data->lock);
7496 list_add_tail(&ref_node->node, &file_data->ref_list);
7497 spin_unlock(&file_data->lock);
7498 percpu_ref_get(&file_data->refs);
7499 return ret;
7500out_fput:
7501 for (i = 0; i < ctx->nr_user_files; i++) {
7502 file = io_file_from_index(ctx, i);
7503 if (file)
7504 fput(file);
7505 }
7506 for (i = 0; i < nr_tables; i++)
7507 kfree(file_data->table[i].files);
7508 ctx->nr_user_files = 0;
7509out_ref:
7510 percpu_ref_exit(&file_data->refs);
7511out_free:
7512 kfree(file_data->table);
7513 kfree(file_data);
7514 ctx->file_data = NULL;
7515 return ret;
7516}
7517
7518static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file,
7519 int index)
7520{
7521#if defined(CONFIG_UNIX)
7522 struct sock *sock = ctx->ring_sock->sk;
7523 struct sk_buff_head *head = &sock->sk_receive_queue;
7524 struct sk_buff *skb;
7525
7526 /*
7527 * See if we can merge this file into an existing skb SCM_RIGHTS
7528 * file set. If there's no room, fall back to allocating a new skb
7529 * and filling it in.
7530 */
7531 spin_lock_irq(&head->lock);
7532 skb = skb_peek(head);
7533 if (skb) {
7534 struct scm_fp_list *fpl = UNIXCB(skb).fp;
7535
7536 if (fpl->count < SCM_MAX_FD) {
7537 __skb_unlink(skb, head);
7538 spin_unlock_irq(&head->lock);
7539 fpl->fp[fpl->count] = get_file(file);
7540 unix_inflight(fpl->user, fpl->fp[fpl->count]);
7541 fpl->count++;
7542 spin_lock_irq(&head->lock);
7543 __skb_queue_head(head, skb);
7544 } else {
7545 skb = NULL;
7546 }
7547 }
7548 spin_unlock_irq(&head->lock);
7549
7550 if (skb) {
7551 fput(file);
7552 return 0;
7553 }
7554
7555 return __io_sqe_files_scm(ctx, 1, index);
7556#else
7557 return 0;
7558#endif
7559}
7560
7561static int io_queue_file_removal(struct fixed_file_data *data,
7562 struct file *file)
7563{
7564 struct io_file_put *pfile;
7565 struct fixed_file_ref_node *ref_node = data->node;
7566
7567 pfile = kzalloc(sizeof(*pfile), GFP_KERNEL);
7568 if (!pfile)
7569 return -ENOMEM;
7570
7571 pfile->file = file;
7572 list_add(&pfile->list, &ref_node->file_list);
7573
7574 return 0;
7575}
7576
7577static int __io_sqe_files_update(struct io_ring_ctx *ctx,
7578 struct io_uring_files_update *up,
7579 unsigned nr_args)
7580{
7581 struct fixed_file_data *data = ctx->file_data;
7582 struct fixed_file_ref_node *ref_node;
7583 struct file *file;
7584 __s32 __user *fds;
7585 int fd, i, err;
7586 __u32 done;
7587 bool needs_switch = false;
7588
7589 if (check_add_overflow(up->offset, nr_args, &done))
7590 return -EOVERFLOW;
7591 if (done > ctx->nr_user_files)
7592 return -EINVAL;
7593
7594 ref_node = alloc_fixed_file_ref_node(ctx);
7595 if (IS_ERR(ref_node))
7596 return PTR_ERR(ref_node);
7597
7598 done = 0;
7599 fds = u64_to_user_ptr(up->fds);
7600 while (nr_args) {
7601 struct fixed_file_table *table;
7602 unsigned index;
7603
7604 err = 0;
7605 if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
7606 err = -EFAULT;
7607 break;
7608 }
7609 i = array_index_nospec(up->offset, ctx->nr_user_files);
7610 table = &ctx->file_data->table[i >> IORING_FILE_TABLE_SHIFT];
7611 index = i & IORING_FILE_TABLE_MASK;
7612 if (table->files[index]) {
7613 file = table->files[index];
7614 err = io_queue_file_removal(data, file);
7615 if (err)
7616 break;
7617 table->files[index] = NULL;
7618 needs_switch = true;
7619 }
7620 if (fd != -1) {
7621 file = fget(fd);
7622 if (!file) {
7623 err = -EBADF;
7624 break;
7625 }
7626 /*
7627 * Don't allow io_uring instances to be registered. If
7628 * UNIX isn't enabled, then this causes a reference
7629 * cycle and this instance can never get freed. If UNIX
7630 * is enabled we'll handle it just fine, but there's
7631 * still no point in allowing a ring fd as it doesn't
7632 * support regular read/write anyway.
7633 */
7634 if (file->f_op == &io_uring_fops) {
7635 fput(file);
7636 err = -EBADF;
7637 break;
7638 }
7639 table->files[index] = file;
7640 err = io_sqe_file_register(ctx, file, i);
7641 if (err) {
7642 table->files[index] = NULL;
7643 fput(file);
7644 break;
7645 }
7646 }
7647 nr_args--;
7648 done++;
7649 up->offset++;
7650 }
7651
7652 if (needs_switch) {
7653 percpu_ref_kill(&data->node->refs);
7654 spin_lock(&data->lock);
7655 list_add_tail(&ref_node->node, &data->ref_list);
7656 data->node = ref_node;
7657 spin_unlock(&data->lock);
7658 percpu_ref_get(&ctx->file_data->refs);
7659 } else
7660 destroy_fixed_file_ref_node(ref_node);
7661
7662 return done ? done : err;
7663}
7664
7665static int io_sqe_files_update(struct io_ring_ctx *ctx, void __user *arg,
7666 unsigned nr_args)
7667{
7668 struct io_uring_files_update up;
7669
7670 if (!ctx->file_data)
7671 return -ENXIO;
7672 if (!nr_args)
7673 return -EINVAL;
7674 if (copy_from_user(&up, arg, sizeof(up)))
7675 return -EFAULT;
7676 if (up.resv)
7677 return -EINVAL;
7678
7679 return __io_sqe_files_update(ctx, &up, nr_args);
7680}
7681
7682static void io_free_work(struct io_wq_work *work)
7683{
7684 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
7685
7686 /* Consider that io_steal_work() relies on this ref */
7687 io_put_req(req);
7688}
7689
7690static int io_init_wq_offload(struct io_ring_ctx *ctx,
7691 struct io_uring_params *p)
7692{
7693 struct io_wq_data data;
7694 struct fd f;
7695 struct io_ring_ctx *ctx_attach;
7696 unsigned int concurrency;
7697 int ret = 0;
7698
7699 data.user = ctx->user;
7700 data.free_work = io_free_work;
7701 data.do_work = io_wq_submit_work;
7702
7703 if (!(p->flags & IORING_SETUP_ATTACH_WQ)) {
7704 /* Do QD, or 4 * CPUS, whatever is smallest */
7705 concurrency = min(ctx->sq_entries, 4 * num_online_cpus());
7706
7707 ctx->io_wq = io_wq_create(concurrency, &data);
7708 if (IS_ERR(ctx->io_wq)) {
7709 ret = PTR_ERR(ctx->io_wq);
7710 ctx->io_wq = NULL;
7711 }
7712 return ret;
7713 }
7714
7715 f = fdget(p->wq_fd);
7716 if (!f.file)
7717 return -EBADF;
7718
7719 if (f.file->f_op != &io_uring_fops) {
7720 ret = -EINVAL;
7721 goto out_fput;
7722 }
7723
7724 ctx_attach = f.file->private_data;
7725 /* @io_wq is protected by holding the fd */
7726 if (!io_wq_get(ctx_attach->io_wq, &data)) {
7727 ret = -EINVAL;
7728 goto out_fput;
7729 }
7730
7731 ctx->io_wq = ctx_attach->io_wq;
7732out_fput:
7733 fdput(f);
7734 return ret;
7735}
7736
7737static int io_uring_alloc_task_context(struct task_struct *task)
7738{
7739 struct io_uring_task *tctx;
7740 int ret;
7741
7742 tctx = kmalloc(sizeof(*tctx), GFP_KERNEL);
7743 if (unlikely(!tctx))
7744 return -ENOMEM;
7745
7746 ret = percpu_counter_init(&tctx->inflight, 0, GFP_KERNEL);
7747 if (unlikely(ret)) {
7748 kfree(tctx);
7749 return ret;
7750 }
7751
7752 xa_init(&tctx->xa);
7753 init_waitqueue_head(&tctx->wait);
7754 tctx->last = NULL;
7755 atomic_set(&tctx->in_idle, 0);
7756 tctx->sqpoll = false;
7757 io_init_identity(&tctx->__identity);
7758 tctx->identity = &tctx->__identity;
7759 task->io_uring = tctx;
7760 return 0;
7761}
7762
7763void __io_uring_free(struct task_struct *tsk)
7764{
7765 struct io_uring_task *tctx = tsk->io_uring;
7766
7767 WARN_ON_ONCE(!xa_empty(&tctx->xa));
7768 WARN_ON_ONCE(refcount_read(&tctx->identity->count) != 1);
7769 if (tctx->identity != &tctx->__identity)
7770 kfree(tctx->identity);
7771 percpu_counter_destroy(&tctx->inflight);
7772 kfree(tctx);
7773 tsk->io_uring = NULL;
7774}
7775
7776static int io_sq_offload_create(struct io_ring_ctx *ctx,
7777 struct io_uring_params *p)
7778{
7779 int ret;
7780
7781 if (ctx->flags & IORING_SETUP_SQPOLL) {
7782 struct io_sq_data *sqd;
7783
7784 ret = -EPERM;
7785 if (!capable(CAP_SYS_ADMIN))
7786 goto err;
7787
7788 sqd = io_get_sq_data(p);
7789 if (IS_ERR(sqd)) {
7790 ret = PTR_ERR(sqd);
7791 goto err;
7792 }
7793
7794 ctx->sq_data = sqd;
7795 io_sq_thread_park(sqd);
7796 mutex_lock(&sqd->ctx_lock);
7797 list_add(&ctx->sqd_list, &sqd->ctx_new_list);
7798 mutex_unlock(&sqd->ctx_lock);
7799 io_sq_thread_unpark(sqd);
7800
7801 ctx->sq_thread_idle = msecs_to_jiffies(p->sq_thread_idle);
7802 if (!ctx->sq_thread_idle)
7803 ctx->sq_thread_idle = HZ;
7804
7805 if (sqd->thread)
7806 goto done;
7807
7808 if (p->flags & IORING_SETUP_SQ_AFF) {
7809 int cpu = p->sq_thread_cpu;
7810
7811 ret = -EINVAL;
7812 if (cpu >= nr_cpu_ids)
7813 goto err;
7814 if (!cpu_online(cpu))
7815 goto err;
7816
7817 sqd->thread = kthread_create_on_cpu(io_sq_thread, sqd,
7818 cpu, "io_uring-sq");
7819 } else {
7820 sqd->thread = kthread_create(io_sq_thread, sqd,
7821 "io_uring-sq");
7822 }
7823 if (IS_ERR(sqd->thread)) {
7824 ret = PTR_ERR(sqd->thread);
7825 sqd->thread = NULL;
7826 goto err;
7827 }
7828 ret = io_uring_alloc_task_context(sqd->thread);
7829 if (ret)
7830 goto err;
7831 } else if (p->flags & IORING_SETUP_SQ_AFF) {
7832 /* Can't have SQ_AFF without SQPOLL */
7833 ret = -EINVAL;
7834 goto err;
7835 }
7836
7837done:
7838 ret = io_init_wq_offload(ctx, p);
7839 if (ret)
7840 goto err;
7841
7842 return 0;
7843err:
7844 io_finish_async(ctx);
7845 return ret;
7846}
7847
7848static void io_sq_offload_start(struct io_ring_ctx *ctx)
7849{
7850 struct io_sq_data *sqd = ctx->sq_data;
7851
7852 if ((ctx->flags & IORING_SETUP_SQPOLL) && sqd->thread)
7853 wake_up_process(sqd->thread);
7854}
7855
7856static inline void __io_unaccount_mem(struct user_struct *user,
7857 unsigned long nr_pages)
7858{
7859 atomic_long_sub(nr_pages, &user->locked_vm);
7860}
7861
7862static inline int __io_account_mem(struct user_struct *user,
7863 unsigned long nr_pages)
7864{
7865 unsigned long page_limit, cur_pages, new_pages;
7866
7867 /* Don't allow more pages than we can safely lock */
7868 page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
7869
7870 do {
7871 cur_pages = atomic_long_read(&user->locked_vm);
7872 new_pages = cur_pages + nr_pages;
7873 if (new_pages > page_limit)
7874 return -ENOMEM;
7875 } while (atomic_long_cmpxchg(&user->locked_vm, cur_pages,
7876 new_pages) != cur_pages);
7877
7878 return 0;
7879}
7880
7881static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages,
7882 enum io_mem_account acct)
7883{
7884 if (ctx->limit_mem)
7885 __io_unaccount_mem(ctx->user, nr_pages);
7886
7887 if (ctx->mm_account) {
7888 if (acct == ACCT_LOCKED)
7889 ctx->mm_account->locked_vm -= nr_pages;
7890 else if (acct == ACCT_PINNED)
7891 atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm);
7892 }
7893}
7894
7895static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages,
7896 enum io_mem_account acct)
7897{
7898 int ret;
7899
7900 if (ctx->limit_mem) {
7901 ret = __io_account_mem(ctx->user, nr_pages);
7902 if (ret)
7903 return ret;
7904 }
7905
7906 if (ctx->mm_account) {
7907 if (acct == ACCT_LOCKED)
7908 ctx->mm_account->locked_vm += nr_pages;
7909 else if (acct == ACCT_PINNED)
7910 atomic64_add(nr_pages, &ctx->mm_account->pinned_vm);
7911 }
7912
7913 return 0;
7914}
7915
7916static void io_mem_free(void *ptr)
7917{
7918 struct page *page;
7919
7920 if (!ptr)
7921 return;
7922
7923 page = virt_to_head_page(ptr);
7924 if (put_page_testzero(page))
7925 free_compound_page(page);
7926}
7927
7928static void *io_mem_alloc(size_t size)
7929{
7930 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP |
7931 __GFP_NORETRY;
7932
7933 return (void *) __get_free_pages(gfp_flags, get_order(size));
7934}
7935
7936static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries,
7937 size_t *sq_offset)
7938{
7939 struct io_rings *rings;
7940 size_t off, sq_array_size;
7941
7942 off = struct_size(rings, cqes, cq_entries);
7943 if (off == SIZE_MAX)
7944 return SIZE_MAX;
7945
7946#ifdef CONFIG_SMP
7947 off = ALIGN(off, SMP_CACHE_BYTES);
7948 if (off == 0)
7949 return SIZE_MAX;
7950#endif
7951
7952 if (sq_offset)
7953 *sq_offset = off;
7954
7955 sq_array_size = array_size(sizeof(u32), sq_entries);
7956 if (sq_array_size == SIZE_MAX)
7957 return SIZE_MAX;
7958
7959 if (check_add_overflow(off, sq_array_size, &off))
7960 return SIZE_MAX;
7961
7962 return off;
7963}
7964
7965static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries)
7966{
7967 size_t pages;
7968
7969 pages = (size_t)1 << get_order(
7970 rings_size(sq_entries, cq_entries, NULL));
7971 pages += (size_t)1 << get_order(
7972 array_size(sizeof(struct io_uring_sqe), sq_entries));
7973
7974 return pages;
7975}
7976
7977static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx)
7978{
7979 int i, j;
7980
7981 if (!ctx->user_bufs)
7982 return -ENXIO;
7983
7984 for (i = 0; i < ctx->nr_user_bufs; i++) {
7985 struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
7986
7987 for (j = 0; j < imu->nr_bvecs; j++)
7988 unpin_user_page(imu->bvec[j].bv_page);
7989
7990 if (imu->acct_pages)
7991 io_unaccount_mem(ctx, imu->acct_pages, ACCT_PINNED);
7992 kvfree(imu->bvec);
7993 imu->nr_bvecs = 0;
7994 }
7995
7996 kfree(ctx->user_bufs);
7997 ctx->user_bufs = NULL;
7998 ctx->nr_user_bufs = 0;
7999 return 0;
8000}
8001
8002static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst,
8003 void __user *arg, unsigned index)
8004{
8005 struct iovec __user *src;
8006
8007#ifdef CONFIG_COMPAT
8008 if (ctx->compat) {
8009 struct compat_iovec __user *ciovs;
8010 struct compat_iovec ciov;
8011
8012 ciovs = (struct compat_iovec __user *) arg;
8013 if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov)))
8014 return -EFAULT;
8015
8016 dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base);
8017 dst->iov_len = ciov.iov_len;
8018 return 0;
8019 }
8020#endif
8021 src = (struct iovec __user *) arg;
8022 if (copy_from_user(dst, &src[index], sizeof(*dst)))
8023 return -EFAULT;
8024 return 0;
8025}
8026
8027/*
8028 * Not super efficient, but this is just a registration time. And we do cache
8029 * the last compound head, so generally we'll only do a full search if we don't
8030 * match that one.
8031 *
8032 * We check if the given compound head page has already been accounted, to
8033 * avoid double accounting it. This allows us to account the full size of the
8034 * page, not just the constituent pages of a huge page.
8035 */
8036static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
8037 int nr_pages, struct page *hpage)
8038{
8039 int i, j;
8040
8041 /* check current page array */
8042 for (i = 0; i < nr_pages; i++) {
8043 if (!PageCompound(pages[i]))
8044 continue;
8045 if (compound_head(pages[i]) == hpage)
8046 return true;
8047 }
8048
8049 /* check previously registered pages */
8050 for (i = 0; i < ctx->nr_user_bufs; i++) {
8051 struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
8052
8053 for (j = 0; j < imu->nr_bvecs; j++) {
8054 if (!PageCompound(imu->bvec[j].bv_page))
8055 continue;
8056 if (compound_head(imu->bvec[j].bv_page) == hpage)
8057 return true;
8058 }
8059 }
8060
8061 return false;
8062}
8063
8064static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
8065 int nr_pages, struct io_mapped_ubuf *imu,
8066 struct page **last_hpage)
8067{
8068 int i, ret;
8069
8070 for (i = 0; i < nr_pages; i++) {
8071 if (!PageCompound(pages[i])) {
8072 imu->acct_pages++;
8073 } else {
8074 struct page *hpage;
8075
8076 hpage = compound_head(pages[i]);
8077 if (hpage == *last_hpage)
8078 continue;
8079 *last_hpage = hpage;
8080 if (headpage_already_acct(ctx, pages, i, hpage))
8081 continue;
8082 imu->acct_pages += page_size(hpage) >> PAGE_SHIFT;
8083 }
8084 }
8085
8086 if (!imu->acct_pages)
8087 return 0;
8088
8089 ret = io_account_mem(ctx, imu->acct_pages, ACCT_PINNED);
8090 if (ret)
8091 imu->acct_pages = 0;
8092 return ret;
8093}
8094
8095static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
8096 unsigned nr_args)
8097{
8098 struct vm_area_struct **vmas = NULL;
8099 struct page **pages = NULL;
8100 struct page *last_hpage = NULL;
8101 int i, j, got_pages = 0;
8102 int ret = -EINVAL;
8103
8104 if (ctx->user_bufs)
8105 return -EBUSY;
8106 if (!nr_args || nr_args > UIO_MAXIOV)
8107 return -EINVAL;
8108
8109 ctx->user_bufs = kcalloc(nr_args, sizeof(struct io_mapped_ubuf),
8110 GFP_KERNEL);
8111 if (!ctx->user_bufs)
8112 return -ENOMEM;
8113
8114 for (i = 0; i < nr_args; i++) {
8115 struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
8116 unsigned long off, start, end, ubuf;
8117 int pret, nr_pages;
8118 struct iovec iov;
8119 size_t size;
8120
8121 ret = io_copy_iov(ctx, &iov, arg, i);
8122 if (ret)
8123 goto err;
8124
8125 /*
8126 * Don't impose further limits on the size and buffer
8127 * constraints here, we'll -EINVAL later when IO is
8128 * submitted if they are wrong.
8129 */
8130 ret = -EFAULT;
8131 if (!iov.iov_base || !iov.iov_len)
8132 goto err;
8133
8134 /* arbitrary limit, but we need something */
8135 if (iov.iov_len > SZ_1G)
8136 goto err;
8137
8138 ubuf = (unsigned long) iov.iov_base;
8139 end = (ubuf + iov.iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
8140 start = ubuf >> PAGE_SHIFT;
8141 nr_pages = end - start;
8142
8143 ret = 0;
8144 if (!pages || nr_pages > got_pages) {
8145 kvfree(vmas);
8146 kvfree(pages);
8147 pages = kvmalloc_array(nr_pages, sizeof(struct page *),
8148 GFP_KERNEL);
8149 vmas = kvmalloc_array(nr_pages,
8150 sizeof(struct vm_area_struct *),
8151 GFP_KERNEL);
8152 if (!pages || !vmas) {
8153 ret = -ENOMEM;
8154 goto err;
8155 }
8156 got_pages = nr_pages;
8157 }
8158
8159 imu->bvec = kvmalloc_array(nr_pages, sizeof(struct bio_vec),
8160 GFP_KERNEL);
8161 ret = -ENOMEM;
8162 if (!imu->bvec)
8163 goto err;
8164
8165 ret = 0;
8166 mmap_read_lock(current->mm);
8167 pret = pin_user_pages(ubuf, nr_pages,
8168 FOLL_WRITE | FOLL_LONGTERM,
8169 pages, vmas);
8170 if (pret == nr_pages) {
8171 /* don't support file backed memory */
8172 for (j = 0; j < nr_pages; j++) {
8173 struct vm_area_struct *vma = vmas[j];
8174
8175 if (vma->vm_file &&
8176 !is_file_hugepages(vma->vm_file)) {
8177 ret = -EOPNOTSUPP;
8178 break;
8179 }
8180 }
8181 } else {
8182 ret = pret < 0 ? pret : -EFAULT;
8183 }
8184 mmap_read_unlock(current->mm);
8185 if (ret) {
8186 /*
8187 * if we did partial map, or found file backed vmas,
8188 * release any pages we did get
8189 */
8190 if (pret > 0)
8191 unpin_user_pages(pages, pret);
8192 kvfree(imu->bvec);
8193 goto err;
8194 }
8195
8196 ret = io_buffer_account_pin(ctx, pages, pret, imu, &last_hpage);
8197 if (ret) {
8198 unpin_user_pages(pages, pret);
8199 kvfree(imu->bvec);
8200 goto err;
8201 }
8202
8203 off = ubuf & ~PAGE_MASK;
8204 size = iov.iov_len;
8205 for (j = 0; j < nr_pages; j++) {
8206 size_t vec_len;
8207
8208 vec_len = min_t(size_t, size, PAGE_SIZE - off);
8209 imu->bvec[j].bv_page = pages[j];
8210 imu->bvec[j].bv_len = vec_len;
8211 imu->bvec[j].bv_offset = off;
8212 off = 0;
8213 size -= vec_len;
8214 }
8215 /* store original address for later verification */
8216 imu->ubuf = ubuf;
8217 imu->len = iov.iov_len;
8218 imu->nr_bvecs = nr_pages;
8219
8220 ctx->nr_user_bufs++;
8221 }
8222 kvfree(pages);
8223 kvfree(vmas);
8224 return 0;
8225err:
8226 kvfree(pages);
8227 kvfree(vmas);
8228 io_sqe_buffer_unregister(ctx);
8229 return ret;
8230}
8231
8232static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg)
8233{
8234 __s32 __user *fds = arg;
8235 int fd;
8236
8237 if (ctx->cq_ev_fd)
8238 return -EBUSY;
8239
8240 if (copy_from_user(&fd, fds, sizeof(*fds)))
8241 return -EFAULT;
8242
8243 ctx->cq_ev_fd = eventfd_ctx_fdget(fd);
8244 if (IS_ERR(ctx->cq_ev_fd)) {
8245 int ret = PTR_ERR(ctx->cq_ev_fd);
8246 ctx->cq_ev_fd = NULL;
8247 return ret;
8248 }
8249
8250 return 0;
8251}
8252
8253static int io_eventfd_unregister(struct io_ring_ctx *ctx)
8254{
8255 if (ctx->cq_ev_fd) {
8256 eventfd_ctx_put(ctx->cq_ev_fd);
8257 ctx->cq_ev_fd = NULL;
8258 return 0;
8259 }
8260
8261 return -ENXIO;
8262}
8263
8264static int __io_destroy_buffers(int id, void *p, void *data)
8265{
8266 struct io_ring_ctx *ctx = data;
8267 struct io_buffer *buf = p;
8268
8269 __io_remove_buffers(ctx, buf, id, -1U);
8270 return 0;
8271}
8272
8273static void io_destroy_buffers(struct io_ring_ctx *ctx)
8274{
8275 idr_for_each(&ctx->io_buffer_idr, __io_destroy_buffers, ctx);
8276 idr_destroy(&ctx->io_buffer_idr);
8277}
8278
8279static void io_ring_ctx_free(struct io_ring_ctx *ctx)
8280{
8281 io_finish_async(ctx);
8282 io_sqe_buffer_unregister(ctx);
8283
8284 if (ctx->sqo_task) {
8285 put_task_struct(ctx->sqo_task);
8286 ctx->sqo_task = NULL;
8287 mmdrop(ctx->mm_account);
8288 ctx->mm_account = NULL;
8289 }
8290
8291#ifdef CONFIG_BLK_CGROUP
8292 if (ctx->sqo_blkcg_css)
8293 css_put(ctx->sqo_blkcg_css);
8294#endif
8295
8296 io_sqe_files_unregister(ctx);
8297 io_eventfd_unregister(ctx);
8298 io_destroy_buffers(ctx);
8299 idr_destroy(&ctx->personality_idr);
8300
8301#if defined(CONFIG_UNIX)
8302 if (ctx->ring_sock) {
8303 ctx->ring_sock->file = NULL; /* so that iput() is called */
8304 sock_release(ctx->ring_sock);
8305 }
8306#endif
8307
8308 io_mem_free(ctx->rings);
8309 io_mem_free(ctx->sq_sqes);
8310
8311 percpu_ref_exit(&ctx->refs);
8312 free_uid(ctx->user);
8313 put_cred(ctx->creds);
8314 kfree(ctx->cancel_hash);
8315 kmem_cache_free(req_cachep, ctx->fallback_req);
8316 kfree(ctx);
8317}
8318
8319static __poll_t io_uring_poll(struct file *file, poll_table *wait)
8320{
8321 struct io_ring_ctx *ctx = file->private_data;
8322 __poll_t mask = 0;
8323
8324 poll_wait(file, &ctx->cq_wait, wait);
8325 /*
8326 * synchronizes with barrier from wq_has_sleeper call in
8327 * io_commit_cqring
8328 */
8329 smp_rmb();
8330 if (!io_sqring_full(ctx))
8331 mask |= EPOLLOUT | EPOLLWRNORM;
8332 if (io_cqring_events(ctx, false))
8333 mask |= EPOLLIN | EPOLLRDNORM;
8334
8335 return mask;
8336}
8337
8338static int io_uring_fasync(int fd, struct file *file, int on)
8339{
8340 struct io_ring_ctx *ctx = file->private_data;
8341
8342 return fasync_helper(fd, file, on, &ctx->cq_fasync);
8343}
8344
8345static int io_remove_personalities(int id, void *p, void *data)
8346{
8347 struct io_ring_ctx *ctx = data;
8348 struct io_identity *iod;
8349
8350 iod = idr_remove(&ctx->personality_idr, id);
8351 if (iod) {
8352 put_cred(iod->creds);
8353 if (refcount_dec_and_test(&iod->count))
8354 kfree(iod);
8355 }
8356 return 0;
8357}
8358
8359static void io_ring_exit_work(struct work_struct *work)
8360{
8361 struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx,
8362 exit_work);
8363
8364 /*
8365 * If we're doing polled IO and end up having requests being
8366 * submitted async (out-of-line), then completions can come in while
8367 * we're waiting for refs to drop. We need to reap these manually,
8368 * as nobody else will be looking for them.
8369 */
8370 do {
8371 if (ctx->rings)
8372 io_cqring_overflow_flush(ctx, true, NULL, NULL);
8373 io_iopoll_try_reap_events(ctx);
8374 } while (!wait_for_completion_timeout(&ctx->ref_comp, HZ/20));
8375 io_ring_ctx_free(ctx);
8376}
8377
8378static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
8379{
8380 mutex_lock(&ctx->uring_lock);
8381 percpu_ref_kill(&ctx->refs);
8382 mutex_unlock(&ctx->uring_lock);
8383
8384 io_kill_timeouts(ctx, NULL);
8385 io_poll_remove_all(ctx, NULL);
8386
8387 if (ctx->io_wq)
8388 io_wq_cancel_all(ctx->io_wq);
8389
8390 /* if we failed setting up the ctx, we might not have any rings */
8391 if (ctx->rings)
8392 io_cqring_overflow_flush(ctx, true, NULL, NULL);
8393 io_iopoll_try_reap_events(ctx);
8394 idr_for_each(&ctx->personality_idr, io_remove_personalities, ctx);
8395
8396 /*
8397 * Do this upfront, so we won't have a grace period where the ring
8398 * is closed but resources aren't reaped yet. This can cause
8399 * spurious failure in setting up a new ring.
8400 */
8401 io_unaccount_mem(ctx, ring_pages(ctx->sq_entries, ctx->cq_entries),
8402 ACCT_LOCKED);
8403
8404 INIT_WORK(&ctx->exit_work, io_ring_exit_work);
8405 /*
8406 * Use system_unbound_wq to avoid spawning tons of event kworkers
8407 * if we're exiting a ton of rings at the same time. It just adds
8408 * noise and overhead, there's no discernable change in runtime
8409 * over using system_wq.
8410 */
8411 queue_work(system_unbound_wq, &ctx->exit_work);
8412}
8413
8414static int io_uring_release(struct inode *inode, struct file *file)
8415{
8416 struct io_ring_ctx *ctx = file->private_data;
8417
8418 file->private_data = NULL;
8419 io_ring_ctx_wait_and_kill(ctx);
8420 return 0;
8421}
8422
8423static bool io_wq_files_match(struct io_wq_work *work, void *data)
8424{
8425 struct files_struct *files = data;
8426
8427 return !files || ((work->flags & IO_WQ_WORK_FILES) &&
8428 work->identity->files == files);
8429}
8430
8431/*
8432 * Returns true if 'preq' is the link parent of 'req'
8433 */
8434static bool io_match_link(struct io_kiocb *preq, struct io_kiocb *req)
8435{
8436 struct io_kiocb *link;
8437
8438 if (!(preq->flags & REQ_F_LINK_HEAD))
8439 return false;
8440
8441 list_for_each_entry(link, &preq->link_list, link_list) {
8442 if (link == req)
8443 return true;
8444 }
8445
8446 return false;
8447}
8448
8449/*
8450 * We're looking to cancel 'req' because it's holding on to our files, but
8451 * 'req' could be a link to another request. See if it is, and cancel that
8452 * parent request if so.
8453 */
8454static bool io_poll_remove_link(struct io_ring_ctx *ctx, struct io_kiocb *req)
8455{
8456 struct hlist_node *tmp;
8457 struct io_kiocb *preq;
8458 bool found = false;
8459 int i;
8460
8461 spin_lock_irq(&ctx->completion_lock);
8462 for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
8463 struct hlist_head *list;
8464
8465 list = &ctx->cancel_hash[i];
8466 hlist_for_each_entry_safe(preq, tmp, list, hash_node) {
8467 found = io_match_link(preq, req);
8468 if (found) {
8469 io_poll_remove_one(preq);
8470 break;
8471 }
8472 }
8473 }
8474 spin_unlock_irq(&ctx->completion_lock);
8475 return found;
8476}
8477
8478static bool io_timeout_remove_link(struct io_ring_ctx *ctx,
8479 struct io_kiocb *req)
8480{
8481 struct io_kiocb *preq;
8482 bool found = false;
8483
8484 spin_lock_irq(&ctx->completion_lock);
8485 list_for_each_entry(preq, &ctx->timeout_list, timeout.list) {
8486 found = io_match_link(preq, req);
8487 if (found) {
8488 __io_timeout_cancel(preq);
8489 break;
8490 }
8491 }
8492 spin_unlock_irq(&ctx->completion_lock);
8493 return found;
8494}
8495
8496static bool io_cancel_link_cb(struct io_wq_work *work, void *data)
8497{
8498 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
8499 bool ret;
8500
8501 if (req->flags & REQ_F_LINK_TIMEOUT) {
8502 unsigned long flags;
8503 struct io_ring_ctx *ctx = req->ctx;
8504
8505 /* protect against races with linked timeouts */
8506 spin_lock_irqsave(&ctx->completion_lock, flags);
8507 ret = io_match_link(req, data);
8508 spin_unlock_irqrestore(&ctx->completion_lock, flags);
8509 } else {
8510 ret = io_match_link(req, data);
8511 }
8512 return ret;
8513}
8514
8515static void io_attempt_cancel(struct io_ring_ctx *ctx, struct io_kiocb *req)
8516{
8517 enum io_wq_cancel cret;
8518
8519 /* cancel this particular work, if it's running */
8520 cret = io_wq_cancel_work(ctx->io_wq, &req->work);
8521 if (cret != IO_WQ_CANCEL_NOTFOUND)
8522 return;
8523
8524 /* find links that hold this pending, cancel those */
8525 cret = io_wq_cancel_cb(ctx->io_wq, io_cancel_link_cb, req, true);
8526 if (cret != IO_WQ_CANCEL_NOTFOUND)
8527 return;
8528
8529 /* if we have a poll link holding this pending, cancel that */
8530 if (io_poll_remove_link(ctx, req))
8531 return;
8532
8533 /* final option, timeout link is holding this req pending */
8534 io_timeout_remove_link(ctx, req);
8535}
8536
8537static void io_cancel_defer_files(struct io_ring_ctx *ctx,
8538 struct task_struct *task,
8539 struct files_struct *files)
8540{
8541 struct io_defer_entry *de = NULL;
8542 LIST_HEAD(list);
8543
8544 spin_lock_irq(&ctx->completion_lock);
8545 list_for_each_entry_reverse(de, &ctx->defer_list, list) {
8546 if (io_task_match(de->req, task) &&
8547 io_match_files(de->req, files)) {
8548 list_cut_position(&list, &ctx->defer_list, &de->list);
8549 break;
8550 }
8551 }
8552 spin_unlock_irq(&ctx->completion_lock);
8553
8554 while (!list_empty(&list)) {
8555 de = list_first_entry(&list, struct io_defer_entry, list);
8556 list_del_init(&de->list);
8557 req_set_fail_links(de->req);
8558 io_put_req(de->req);
8559 io_req_complete(de->req, -ECANCELED);
8560 kfree(de);
8561 }
8562}
8563
8564/*
8565 * Returns true if we found and killed one or more files pinning requests
8566 */
8567static bool io_uring_cancel_files(struct io_ring_ctx *ctx,
8568 struct files_struct *files)
8569{
8570 if (list_empty_careful(&ctx->inflight_list))
8571 return false;
8572
8573 /* cancel all at once, should be faster than doing it one by one*/
8574 io_wq_cancel_cb(ctx->io_wq, io_wq_files_match, files, true);
8575
8576 while (!list_empty_careful(&ctx->inflight_list)) {
8577 struct io_kiocb *cancel_req = NULL, *req;
8578 DEFINE_WAIT(wait);
8579
8580 spin_lock_irq(&ctx->inflight_lock);
8581 list_for_each_entry(req, &ctx->inflight_list, inflight_entry) {
8582 if (files && (req->work.flags & IO_WQ_WORK_FILES) &&
8583 req->work.identity->files != files)
8584 continue;
8585 /* req is being completed, ignore */
8586 if (!refcount_inc_not_zero(&req->refs))
8587 continue;
8588 cancel_req = req;
8589 break;
8590 }
8591 if (cancel_req)
8592 prepare_to_wait(&ctx->inflight_wait, &wait,
8593 TASK_UNINTERRUPTIBLE);
8594 spin_unlock_irq(&ctx->inflight_lock);
8595
8596 /* We need to keep going until we don't find a matching req */
8597 if (!cancel_req)
8598 break;
8599 /* cancel this request, or head link requests */
8600 io_attempt_cancel(ctx, cancel_req);
8601 io_put_req(cancel_req);
8602 /* cancellations _may_ trigger task work */
8603 io_run_task_work();
8604 schedule();
8605 finish_wait(&ctx->inflight_wait, &wait);
8606 }
8607
8608 return true;
8609}
8610
8611static bool io_cancel_task_cb(struct io_wq_work *work, void *data)
8612{
8613 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
8614 struct task_struct *task = data;
8615
8616 return io_task_match(req, task);
8617}
8618
8619static bool __io_uring_cancel_task_requests(struct io_ring_ctx *ctx,
8620 struct task_struct *task,
8621 struct files_struct *files)
8622{
8623 bool ret;
8624
8625 ret = io_uring_cancel_files(ctx, files);
8626 if (!files) {
8627 enum io_wq_cancel cret;
8628
8629 cret = io_wq_cancel_cb(ctx->io_wq, io_cancel_task_cb, task, true);
8630 if (cret != IO_WQ_CANCEL_NOTFOUND)
8631 ret = true;
8632
8633 /* SQPOLL thread does its own polling */
8634 if (!(ctx->flags & IORING_SETUP_SQPOLL)) {
8635 while (!list_empty_careful(&ctx->iopoll_list)) {
8636 io_iopoll_try_reap_events(ctx);
8637 ret = true;
8638 }
8639 }
8640
8641 ret |= io_poll_remove_all(ctx, task);
8642 ret |= io_kill_timeouts(ctx, task);
8643 }
8644
8645 return ret;
8646}
8647
8648/*
8649 * We need to iteratively cancel requests, in case a request has dependent
8650 * hard links. These persist even for failure of cancelations, hence keep
8651 * looping until none are found.
8652 */
8653static void io_uring_cancel_task_requests(struct io_ring_ctx *ctx,
8654 struct files_struct *files)
8655{
8656 struct task_struct *task = current;
8657
8658 if ((ctx->flags & IORING_SETUP_SQPOLL) && ctx->sq_data) {
8659 task = ctx->sq_data->thread;
8660 atomic_inc(&task->io_uring->in_idle);
8661 io_sq_thread_park(ctx->sq_data);
8662 }
8663
8664 if (files)
8665 io_cancel_defer_files(ctx, NULL, files);
8666 else
8667 io_cancel_defer_files(ctx, task, NULL);
8668
8669 io_cqring_overflow_flush(ctx, true, task, files);
8670
8671 while (__io_uring_cancel_task_requests(ctx, task, files)) {
8672 io_run_task_work();
8673 cond_resched();
8674 }
8675
8676 if ((ctx->flags & IORING_SETUP_SQPOLL) && ctx->sq_data) {
8677 atomic_dec(&task->io_uring->in_idle);
8678 /*
8679 * If the files that are going away are the ones in the thread
8680 * identity, clear them out.
8681 */
8682 if (task->io_uring->identity->files == files)
8683 task->io_uring->identity->files = NULL;
8684 io_sq_thread_unpark(ctx->sq_data);
8685 }
8686}
8687
8688/*
8689 * Note that this task has used io_uring. We use it for cancelation purposes.
8690 */
8691static int io_uring_add_task_file(struct io_ring_ctx *ctx, struct file *file)
8692{
8693 struct io_uring_task *tctx = current->io_uring;
8694
8695 if (unlikely(!tctx)) {
8696 int ret;
8697
8698 ret = io_uring_alloc_task_context(current);
8699 if (unlikely(ret))
8700 return ret;
8701 tctx = current->io_uring;
8702 }
8703 if (tctx->last != file) {
8704 void *old = xa_load(&tctx->xa, (unsigned long)file);
8705
8706 if (!old) {
8707 get_file(file);
8708 xa_store(&tctx->xa, (unsigned long)file, file, GFP_KERNEL);
8709 }
8710 tctx->last = file;
8711 }
8712
8713 /*
8714 * This is race safe in that the task itself is doing this, hence it
8715 * cannot be going through the exit/cancel paths at the same time.
8716 * This cannot be modified while exit/cancel is running.
8717 */
8718 if (!tctx->sqpoll && (ctx->flags & IORING_SETUP_SQPOLL))
8719 tctx->sqpoll = true;
8720
8721 return 0;
8722}
8723
8724/*
8725 * Remove this io_uring_file -> task mapping.
8726 */
8727static void io_uring_del_task_file(struct file *file)
8728{
8729 struct io_uring_task *tctx = current->io_uring;
8730
8731 if (tctx->last == file)
8732 tctx->last = NULL;
8733 file = xa_erase(&tctx->xa, (unsigned long)file);
8734 if (file)
8735 fput(file);
8736}
8737
8738/*
8739 * Drop task note for this file if we're the only ones that hold it after
8740 * pending fput()
8741 */
8742static void io_uring_attempt_task_drop(struct file *file)
8743{
8744 if (!current->io_uring)
8745 return;
8746 /*
8747 * fput() is pending, will be 2 if the only other ref is our potential
8748 * task file note. If the task is exiting, drop regardless of count.
8749 */
8750 if (fatal_signal_pending(current) || (current->flags & PF_EXITING) ||
8751 atomic_long_read(&file->f_count) == 2)
8752 io_uring_del_task_file(file);
8753}
8754
8755void __io_uring_files_cancel(struct files_struct *files)
8756{
8757 struct io_uring_task *tctx = current->io_uring;
8758 struct file *file;
8759 unsigned long index;
8760
8761 /* make sure overflow events are dropped */
8762 atomic_inc(&tctx->in_idle);
8763
8764 xa_for_each(&tctx->xa, index, file) {
8765 struct io_ring_ctx *ctx = file->private_data;
8766
8767 io_uring_cancel_task_requests(ctx, files);
8768 if (files)
8769 io_uring_del_task_file(file);
8770 }
8771
8772 atomic_dec(&tctx->in_idle);
8773}
8774
8775static s64 tctx_inflight(struct io_uring_task *tctx)
8776{
8777 unsigned long index;
8778 struct file *file;
8779 s64 inflight;
8780
8781 inflight = percpu_counter_sum(&tctx->inflight);
8782 if (!tctx->sqpoll)
8783 return inflight;
8784
8785 /*
8786 * If we have SQPOLL rings, then we need to iterate and find them, and
8787 * add the pending count for those.
8788 */
8789 xa_for_each(&tctx->xa, index, file) {
8790 struct io_ring_ctx *ctx = file->private_data;
8791
8792 if (ctx->flags & IORING_SETUP_SQPOLL) {
8793 struct io_uring_task *__tctx = ctx->sqo_task->io_uring;
8794
8795 inflight += percpu_counter_sum(&__tctx->inflight);
8796 }
8797 }
8798
8799 return inflight;
8800}
8801
8802/*
8803 * Find any io_uring fd that this task has registered or done IO on, and cancel
8804 * requests.
8805 */
8806void __io_uring_task_cancel(void)
8807{
8808 struct io_uring_task *tctx = current->io_uring;
8809 DEFINE_WAIT(wait);
8810 s64 inflight;
8811
8812 /* make sure overflow events are dropped */
8813 atomic_inc(&tctx->in_idle);
8814
8815 do {
8816 /* read completions before cancelations */
8817 inflight = tctx_inflight(tctx);
8818 if (!inflight)
8819 break;
8820 __io_uring_files_cancel(NULL);
8821
8822 prepare_to_wait(&tctx->wait, &wait, TASK_UNINTERRUPTIBLE);
8823
8824 /*
8825 * If we've seen completions, retry. This avoids a race where
8826 * a completion comes in before we did prepare_to_wait().
8827 */
8828 if (inflight != tctx_inflight(tctx))
8829 continue;
8830 schedule();
8831 } while (1);
8832
8833 finish_wait(&tctx->wait, &wait);
8834 atomic_dec(&tctx->in_idle);
8835}
8836
8837static int io_uring_flush(struct file *file, void *data)
8838{
8839 io_uring_attempt_task_drop(file);
8840 return 0;
8841}
8842
8843static void *io_uring_validate_mmap_request(struct file *file,
8844 loff_t pgoff, size_t sz)
8845{
8846 struct io_ring_ctx *ctx = file->private_data;
8847 loff_t offset = pgoff << PAGE_SHIFT;
8848 struct page *page;
8849 void *ptr;
8850
8851 switch (offset) {
8852 case IORING_OFF_SQ_RING:
8853 case IORING_OFF_CQ_RING:
8854 ptr = ctx->rings;
8855 break;
8856 case IORING_OFF_SQES:
8857 ptr = ctx->sq_sqes;
8858 break;
8859 default:
8860 return ERR_PTR(-EINVAL);
8861 }
8862
8863 page = virt_to_head_page(ptr);
8864 if (sz > page_size(page))
8865 return ERR_PTR(-EINVAL);
8866
8867 return ptr;
8868}
8869
8870#ifdef CONFIG_MMU
8871
8872static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
8873{
8874 size_t sz = vma->vm_end - vma->vm_start;
8875 unsigned long pfn;
8876 void *ptr;
8877
8878 ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz);
8879 if (IS_ERR(ptr))
8880 return PTR_ERR(ptr);
8881
8882 pfn = virt_to_phys(ptr) >> PAGE_SHIFT;
8883 return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot);
8884}
8885
8886#else /* !CONFIG_MMU */
8887
8888static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
8889{
8890 return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -EINVAL;
8891}
8892
8893static unsigned int io_uring_nommu_mmap_capabilities(struct file *file)
8894{
8895 return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE;
8896}
8897
8898static unsigned long io_uring_nommu_get_unmapped_area(struct file *file,
8899 unsigned long addr, unsigned long len,
8900 unsigned long pgoff, unsigned long flags)
8901{
8902 void *ptr;
8903
8904 ptr = io_uring_validate_mmap_request(file, pgoff, len);
8905 if (IS_ERR(ptr))
8906 return PTR_ERR(ptr);
8907
8908 return (unsigned long) ptr;
8909}
8910
8911#endif /* !CONFIG_MMU */
8912
8913static void io_sqpoll_wait_sq(struct io_ring_ctx *ctx)
8914{
8915 DEFINE_WAIT(wait);
8916
8917 do {
8918 if (!io_sqring_full(ctx))
8919 break;
8920
8921 prepare_to_wait(&ctx->sqo_sq_wait, &wait, TASK_INTERRUPTIBLE);
8922
8923 if (!io_sqring_full(ctx))
8924 break;
8925
8926 schedule();
8927 } while (!signal_pending(current));
8928
8929 finish_wait(&ctx->sqo_sq_wait, &wait);
8930}
8931
8932SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
8933 u32, min_complete, u32, flags, const sigset_t __user *, sig,
8934 size_t, sigsz)
8935{
8936 struct io_ring_ctx *ctx;
8937 long ret = -EBADF;
8938 int submitted = 0;
8939 struct fd f;
8940
8941 io_run_task_work();
8942
8943 if (flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP |
8944 IORING_ENTER_SQ_WAIT))
8945 return -EINVAL;
8946
8947 f = fdget(fd);
8948 if (!f.file)
8949 return -EBADF;
8950
8951 ret = -EOPNOTSUPP;
8952 if (f.file->f_op != &io_uring_fops)
8953 goto out_fput;
8954
8955 ret = -ENXIO;
8956 ctx = f.file->private_data;
8957 if (!percpu_ref_tryget(&ctx->refs))
8958 goto out_fput;
8959
8960 ret = -EBADFD;
8961 if (ctx->flags & IORING_SETUP_R_DISABLED)
8962 goto out;
8963
8964 /*
8965 * For SQ polling, the thread will do all submissions and completions.
8966 * Just return the requested submit count, and wake the thread if
8967 * we were asked to.
8968 */
8969 ret = 0;
8970 if (ctx->flags & IORING_SETUP_SQPOLL) {
8971 if (!list_empty_careful(&ctx->cq_overflow_list))
8972 io_cqring_overflow_flush(ctx, false, NULL, NULL);
8973 if (flags & IORING_ENTER_SQ_WAKEUP)
8974 wake_up(&ctx->sq_data->wait);
8975 if (flags & IORING_ENTER_SQ_WAIT)
8976 io_sqpoll_wait_sq(ctx);
8977 submitted = to_submit;
8978 } else if (to_submit) {
8979 ret = io_uring_add_task_file(ctx, f.file);
8980 if (unlikely(ret))
8981 goto out;
8982 mutex_lock(&ctx->uring_lock);
8983 submitted = io_submit_sqes(ctx, to_submit);
8984 mutex_unlock(&ctx->uring_lock);
8985
8986 if (submitted != to_submit)
8987 goto out;
8988 }
8989 if (flags & IORING_ENTER_GETEVENTS) {
8990 min_complete = min(min_complete, ctx->cq_entries);
8991
8992 /*
8993 * When SETUP_IOPOLL and SETUP_SQPOLL are both enabled, user
8994 * space applications don't need to do io completion events
8995 * polling again, they can rely on io_sq_thread to do polling
8996 * work, which can reduce cpu usage and uring_lock contention.
8997 */
8998 if (ctx->flags & IORING_SETUP_IOPOLL &&
8999 !(ctx->flags & IORING_SETUP_SQPOLL)) {
9000 ret = io_iopoll_check(ctx, min_complete);
9001 } else {
9002 ret = io_cqring_wait(ctx, min_complete, sig, sigsz);
9003 }
9004 }
9005
9006out:
9007 percpu_ref_put(&ctx->refs);
9008out_fput:
9009 fdput(f);
9010 return submitted ? submitted : ret;
9011}
9012
9013#ifdef CONFIG_PROC_FS
9014static int io_uring_show_cred(int id, void *p, void *data)
9015{
9016 struct io_identity *iod = p;
9017 const struct cred *cred = iod->creds;
9018 struct seq_file *m = data;
9019 struct user_namespace *uns = seq_user_ns(m);
9020 struct group_info *gi;
9021 kernel_cap_t cap;
9022 unsigned __capi;
9023 int g;
9024
9025 seq_printf(m, "%5d\n", id);
9026 seq_put_decimal_ull(m, "\tUid:\t", from_kuid_munged(uns, cred->uid));
9027 seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->euid));
9028 seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->suid));
9029 seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->fsuid));
9030 seq_put_decimal_ull(m, "\n\tGid:\t", from_kgid_munged(uns, cred->gid));
9031 seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->egid));
9032 seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->sgid));
9033 seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->fsgid));
9034 seq_puts(m, "\n\tGroups:\t");
9035 gi = cred->group_info;
9036 for (g = 0; g < gi->ngroups; g++) {
9037 seq_put_decimal_ull(m, g ? " " : "",
9038 from_kgid_munged(uns, gi->gid[g]));
9039 }
9040 seq_puts(m, "\n\tCapEff:\t");
9041 cap = cred->cap_effective;
9042 CAP_FOR_EACH_U32(__capi)
9043 seq_put_hex_ll(m, NULL, cap.cap[CAP_LAST_U32 - __capi], 8);
9044 seq_putc(m, '\n');
9045 return 0;
9046}
9047
9048static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m)
9049{
9050 struct io_sq_data *sq = NULL;
9051 bool has_lock;
9052 int i;
9053
9054 /*
9055 * Avoid ABBA deadlock between the seq lock and the io_uring mutex,
9056 * since fdinfo case grabs it in the opposite direction of normal use
9057 * cases. If we fail to get the lock, we just don't iterate any
9058 * structures that could be going away outside the io_uring mutex.
9059 */
9060 has_lock = mutex_trylock(&ctx->uring_lock);
9061
9062 if (has_lock && (ctx->flags & IORING_SETUP_SQPOLL))
9063 sq = ctx->sq_data;
9064
9065 seq_printf(m, "SqThread:\t%d\n", sq ? task_pid_nr(sq->thread) : -1);
9066 seq_printf(m, "SqThreadCpu:\t%d\n", sq ? task_cpu(sq->thread) : -1);
9067 seq_printf(m, "UserFiles:\t%u\n", ctx->nr_user_files);
9068 for (i = 0; has_lock && i < ctx->nr_user_files; i++) {
9069 struct fixed_file_table *table;
9070 struct file *f;
9071
9072 table = &ctx->file_data->table[i >> IORING_FILE_TABLE_SHIFT];
9073 f = table->files[i & IORING_FILE_TABLE_MASK];
9074 if (f)
9075 seq_printf(m, "%5u: %s\n", i, file_dentry(f)->d_iname);
9076 else
9077 seq_printf(m, "%5u: <none>\n", i);
9078 }
9079 seq_printf(m, "UserBufs:\t%u\n", ctx->nr_user_bufs);
9080 for (i = 0; has_lock && i < ctx->nr_user_bufs; i++) {
9081 struct io_mapped_ubuf *buf = &ctx->user_bufs[i];
9082
9083 seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf,
9084 (unsigned int) buf->len);
9085 }
9086 if (has_lock && !idr_is_empty(&ctx->personality_idr)) {
9087 seq_printf(m, "Personalities:\n");
9088 idr_for_each(&ctx->personality_idr, io_uring_show_cred, m);
9089 }
9090 seq_printf(m, "PollList:\n");
9091 spin_lock_irq(&ctx->completion_lock);
9092 for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
9093 struct hlist_head *list = &ctx->cancel_hash[i];
9094 struct io_kiocb *req;
9095
9096 hlist_for_each_entry(req, list, hash_node)
9097 seq_printf(m, " op=%d, task_works=%d\n", req->opcode,
9098 req->task->task_works != NULL);
9099 }
9100 spin_unlock_irq(&ctx->completion_lock);
9101 if (has_lock)
9102 mutex_unlock(&ctx->uring_lock);
9103}
9104
9105static void io_uring_show_fdinfo(struct seq_file *m, struct file *f)
9106{
9107 struct io_ring_ctx *ctx = f->private_data;
9108
9109 if (percpu_ref_tryget(&ctx->refs)) {
9110 __io_uring_show_fdinfo(ctx, m);
9111 percpu_ref_put(&ctx->refs);
9112 }
9113}
9114#endif
9115
9116static const struct file_operations io_uring_fops = {
9117 .release = io_uring_release,
9118 .flush = io_uring_flush,
9119 .mmap = io_uring_mmap,
9120#ifndef CONFIG_MMU
9121 .get_unmapped_area = io_uring_nommu_get_unmapped_area,
9122 .mmap_capabilities = io_uring_nommu_mmap_capabilities,
9123#endif
9124 .poll = io_uring_poll,
9125 .fasync = io_uring_fasync,
9126#ifdef CONFIG_PROC_FS
9127 .show_fdinfo = io_uring_show_fdinfo,
9128#endif
9129};
9130
9131static int io_allocate_scq_urings(struct io_ring_ctx *ctx,
9132 struct io_uring_params *p)
9133{
9134 struct io_rings *rings;
9135 size_t size, sq_array_offset;
9136
9137 /* make sure these are sane, as we already accounted them */
9138 ctx->sq_entries = p->sq_entries;
9139 ctx->cq_entries = p->cq_entries;
9140
9141 size = rings_size(p->sq_entries, p->cq_entries, &sq_array_offset);
9142 if (size == SIZE_MAX)
9143 return -EOVERFLOW;
9144
9145 rings = io_mem_alloc(size);
9146 if (!rings)
9147 return -ENOMEM;
9148
9149 ctx->rings = rings;
9150 ctx->sq_array = (u32 *)((char *)rings + sq_array_offset);
9151 rings->sq_ring_mask = p->sq_entries - 1;
9152 rings->cq_ring_mask = p->cq_entries - 1;
9153 rings->sq_ring_entries = p->sq_entries;
9154 rings->cq_ring_entries = p->cq_entries;
9155 ctx->sq_mask = rings->sq_ring_mask;
9156 ctx->cq_mask = rings->cq_ring_mask;
9157
9158 size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
9159 if (size == SIZE_MAX) {
9160 io_mem_free(ctx->rings);
9161 ctx->rings = NULL;
9162 return -EOVERFLOW;
9163 }
9164
9165 ctx->sq_sqes = io_mem_alloc(size);
9166 if (!ctx->sq_sqes) {
9167 io_mem_free(ctx->rings);
9168 ctx->rings = NULL;
9169 return -ENOMEM;
9170 }
9171
9172 return 0;
9173}
9174
9175/*
9176 * Allocate an anonymous fd, this is what constitutes the application
9177 * visible backing of an io_uring instance. The application mmaps this
9178 * fd to gain access to the SQ/CQ ring details. If UNIX sockets are enabled,
9179 * we have to tie this fd to a socket for file garbage collection purposes.
9180 */
9181static int io_uring_get_fd(struct io_ring_ctx *ctx)
9182{
9183 struct file *file;
9184 int ret;
9185
9186#if defined(CONFIG_UNIX)
9187 ret = sock_create_kern(&init_net, PF_UNIX, SOCK_RAW, IPPROTO_IP,
9188 &ctx->ring_sock);
9189 if (ret)
9190 return ret;
9191#endif
9192
9193 ret = get_unused_fd_flags(O_RDWR | O_CLOEXEC);
9194 if (ret < 0)
9195 goto err;
9196
9197 file = anon_inode_getfile("[io_uring]", &io_uring_fops, ctx,
9198 O_RDWR | O_CLOEXEC);
9199 if (IS_ERR(file)) {
9200err_fd:
9201 put_unused_fd(ret);
9202 ret = PTR_ERR(file);
9203 goto err;
9204 }
9205
9206#if defined(CONFIG_UNIX)
9207 ctx->ring_sock->file = file;
9208#endif
9209 if (unlikely(io_uring_add_task_file(ctx, file))) {
9210 file = ERR_PTR(-ENOMEM);
9211 goto err_fd;
9212 }
9213 fd_install(ret, file);
9214 return ret;
9215err:
9216#if defined(CONFIG_UNIX)
9217 sock_release(ctx->ring_sock);
9218 ctx->ring_sock = NULL;
9219#endif
9220 return ret;
9221}
9222
9223static int io_uring_create(unsigned entries, struct io_uring_params *p,
9224 struct io_uring_params __user *params)
9225{
9226 struct user_struct *user = NULL;
9227 struct io_ring_ctx *ctx;
9228 bool limit_mem;
9229 int ret;
9230
9231 if (!entries)
9232 return -EINVAL;
9233 if (entries > IORING_MAX_ENTRIES) {
9234 if (!(p->flags & IORING_SETUP_CLAMP))
9235 return -EINVAL;
9236 entries = IORING_MAX_ENTRIES;
9237 }
9238
9239 /*
9240 * Use twice as many entries for the CQ ring. It's possible for the
9241 * application to drive a higher depth than the size of the SQ ring,
9242 * since the sqes are only used at submission time. This allows for
9243 * some flexibility in overcommitting a bit. If the application has
9244 * set IORING_SETUP_CQSIZE, it will have passed in the desired number
9245 * of CQ ring entries manually.
9246 */
9247 p->sq_entries = roundup_pow_of_two(entries);
9248 if (p->flags & IORING_SETUP_CQSIZE) {
9249 /*
9250 * If IORING_SETUP_CQSIZE is set, we do the same roundup
9251 * to a power-of-two, if it isn't already. We do NOT impose
9252 * any cq vs sq ring sizing.
9253 */
9254 if (!p->cq_entries)
9255 return -EINVAL;
9256 if (p->cq_entries > IORING_MAX_CQ_ENTRIES) {
9257 if (!(p->flags & IORING_SETUP_CLAMP))
9258 return -EINVAL;
9259 p->cq_entries = IORING_MAX_CQ_ENTRIES;
9260 }
9261 p->cq_entries = roundup_pow_of_two(p->cq_entries);
9262 if (p->cq_entries < p->sq_entries)
9263 return -EINVAL;
9264 } else {
9265 p->cq_entries = 2 * p->sq_entries;
9266 }
9267
9268 user = get_uid(current_user());
9269 limit_mem = !capable(CAP_IPC_LOCK);
9270
9271 if (limit_mem) {
9272 ret = __io_account_mem(user,
9273 ring_pages(p->sq_entries, p->cq_entries));
9274 if (ret) {
9275 free_uid(user);
9276 return ret;
9277 }
9278 }
9279
9280 ctx = io_ring_ctx_alloc(p);
9281 if (!ctx) {
9282 if (limit_mem)
9283 __io_unaccount_mem(user, ring_pages(p->sq_entries,
9284 p->cq_entries));
9285 free_uid(user);
9286 return -ENOMEM;
9287 }
9288 ctx->compat = in_compat_syscall();
9289 ctx->user = user;
9290 ctx->creds = get_current_cred();
9291#ifdef CONFIG_AUDIT
9292 ctx->loginuid = current->loginuid;
9293 ctx->sessionid = current->sessionid;
9294#endif
9295 ctx->sqo_task = get_task_struct(current);
9296
9297 /*
9298 * This is just grabbed for accounting purposes. When a process exits,
9299 * the mm is exited and dropped before the files, hence we need to hang
9300 * on to this mm purely for the purposes of being able to unaccount
9301 * memory (locked/pinned vm). It's not used for anything else.
9302 */
9303 mmgrab(current->mm);
9304 ctx->mm_account = current->mm;
9305
9306#ifdef CONFIG_BLK_CGROUP
9307 /*
9308 * The sq thread will belong to the original cgroup it was inited in.
9309 * If the cgroup goes offline (e.g. disabling the io controller), then
9310 * issued bios will be associated with the closest cgroup later in the
9311 * block layer.
9312 */
9313 rcu_read_lock();
9314 ctx->sqo_blkcg_css = blkcg_css();
9315 ret = css_tryget_online(ctx->sqo_blkcg_css);
9316 rcu_read_unlock();
9317 if (!ret) {
9318 /* don't init against a dying cgroup, have the user try again */
9319 ctx->sqo_blkcg_css = NULL;
9320 ret = -ENODEV;
9321 goto err;
9322 }
9323#endif
9324
9325 /*
9326 * Account memory _before_ installing the file descriptor. Once
9327 * the descriptor is installed, it can get closed at any time. Also
9328 * do this before hitting the general error path, as ring freeing
9329 * will un-account as well.
9330 */
9331 io_account_mem(ctx, ring_pages(p->sq_entries, p->cq_entries),
9332 ACCT_LOCKED);
9333 ctx->limit_mem = limit_mem;
9334
9335 ret = io_allocate_scq_urings(ctx, p);
9336 if (ret)
9337 goto err;
9338
9339 ret = io_sq_offload_create(ctx, p);
9340 if (ret)
9341 goto err;
9342
9343 if (!(p->flags & IORING_SETUP_R_DISABLED))
9344 io_sq_offload_start(ctx);
9345
9346 memset(&p->sq_off, 0, sizeof(p->sq_off));
9347 p->sq_off.head = offsetof(struct io_rings, sq.head);
9348 p->sq_off.tail = offsetof(struct io_rings, sq.tail);
9349 p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask);
9350 p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries);
9351 p->sq_off.flags = offsetof(struct io_rings, sq_flags);
9352 p->sq_off.dropped = offsetof(struct io_rings, sq_dropped);
9353 p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings;
9354
9355 memset(&p->cq_off, 0, sizeof(p->cq_off));
9356 p->cq_off.head = offsetof(struct io_rings, cq.head);
9357 p->cq_off.tail = offsetof(struct io_rings, cq.tail);
9358 p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask);
9359 p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries);
9360 p->cq_off.overflow = offsetof(struct io_rings, cq_overflow);
9361 p->cq_off.cqes = offsetof(struct io_rings, cqes);
9362 p->cq_off.flags = offsetof(struct io_rings, cq_flags);
9363
9364 p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP |
9365 IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS |
9366 IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL |
9367 IORING_FEAT_POLL_32BITS;
9368
9369 if (copy_to_user(params, p, sizeof(*p))) {
9370 ret = -EFAULT;
9371 goto err;
9372 }
9373
9374 /*
9375 * Install ring fd as the very last thing, so we don't risk someone
9376 * having closed it before we finish setup
9377 */
9378 ret = io_uring_get_fd(ctx);
9379 if (ret < 0)
9380 goto err;
9381
9382 trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags);
9383 return ret;
9384err:
9385 io_ring_ctx_wait_and_kill(ctx);
9386 return ret;
9387}
9388
9389/*
9390 * Sets up an aio uring context, and returns the fd. Applications asks for a
9391 * ring size, we return the actual sq/cq ring sizes (among other things) in the
9392 * params structure passed in.
9393 */
9394static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
9395{
9396 struct io_uring_params p;
9397 int i;
9398
9399 if (copy_from_user(&p, params, sizeof(p)))
9400 return -EFAULT;
9401 for (i = 0; i < ARRAY_SIZE(p.resv); i++) {
9402 if (p.resv[i])
9403 return -EINVAL;
9404 }
9405
9406 if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL |
9407 IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE |
9408 IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ |
9409 IORING_SETUP_R_DISABLED))
9410 return -EINVAL;
9411
9412 return io_uring_create(entries, &p, params);
9413}
9414
9415SYSCALL_DEFINE2(io_uring_setup, u32, entries,
9416 struct io_uring_params __user *, params)
9417{
9418 return io_uring_setup(entries, params);
9419}
9420
9421static int io_probe(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args)
9422{
9423 struct io_uring_probe *p;
9424 size_t size;
9425 int i, ret;
9426
9427 size = struct_size(p, ops, nr_args);
9428 if (size == SIZE_MAX)
9429 return -EOVERFLOW;
9430 p = kzalloc(size, GFP_KERNEL);
9431 if (!p)
9432 return -ENOMEM;
9433
9434 ret = -EFAULT;
9435 if (copy_from_user(p, arg, size))
9436 goto out;
9437 ret = -EINVAL;
9438 if (memchr_inv(p, 0, size))
9439 goto out;
9440
9441 p->last_op = IORING_OP_LAST - 1;
9442 if (nr_args > IORING_OP_LAST)
9443 nr_args = IORING_OP_LAST;
9444
9445 for (i = 0; i < nr_args; i++) {
9446 p->ops[i].op = i;
9447 if (!io_op_defs[i].not_supported)
9448 p->ops[i].flags = IO_URING_OP_SUPPORTED;
9449 }
9450 p->ops_len = i;
9451
9452 ret = 0;
9453 if (copy_to_user(arg, p, size))
9454 ret = -EFAULT;
9455out:
9456 kfree(p);
9457 return ret;
9458}
9459
9460static int io_register_personality(struct io_ring_ctx *ctx)
9461{
9462 struct io_identity *id;
9463 int ret;
9464
9465 id = kmalloc(sizeof(*id), GFP_KERNEL);
9466 if (unlikely(!id))
9467 return -ENOMEM;
9468
9469 io_init_identity(id);
9470 id->creds = get_current_cred();
9471
9472 ret = idr_alloc_cyclic(&ctx->personality_idr, id, 1, USHRT_MAX, GFP_KERNEL);
9473 if (ret < 0) {
9474 put_cred(id->creds);
9475 kfree(id);
9476 }
9477 return ret;
9478}
9479
9480static int io_unregister_personality(struct io_ring_ctx *ctx, unsigned id)
9481{
9482 struct io_identity *iod;
9483
9484 iod = idr_remove(&ctx->personality_idr, id);
9485 if (iod) {
9486 put_cred(iod->creds);
9487 if (refcount_dec_and_test(&iod->count))
9488 kfree(iod);
9489 return 0;
9490 }
9491
9492 return -EINVAL;
9493}
9494
9495static int io_register_restrictions(struct io_ring_ctx *ctx, void __user *arg,
9496 unsigned int nr_args)
9497{
9498 struct io_uring_restriction *res;
9499 size_t size;
9500 int i, ret;
9501
9502 /* Restrictions allowed only if rings started disabled */
9503 if (!(ctx->flags & IORING_SETUP_R_DISABLED))
9504 return -EBADFD;
9505
9506 /* We allow only a single restrictions registration */
9507 if (ctx->restrictions.registered)
9508 return -EBUSY;
9509
9510 if (!arg || nr_args > IORING_MAX_RESTRICTIONS)
9511 return -EINVAL;
9512
9513 size = array_size(nr_args, sizeof(*res));
9514 if (size == SIZE_MAX)
9515 return -EOVERFLOW;
9516
9517 res = memdup_user(arg, size);
9518 if (IS_ERR(res))
9519 return PTR_ERR(res);
9520
9521 ret = 0;
9522
9523 for (i = 0; i < nr_args; i++) {
9524 switch (res[i].opcode) {
9525 case IORING_RESTRICTION_REGISTER_OP:
9526 if (res[i].register_op >= IORING_REGISTER_LAST) {
9527 ret = -EINVAL;
9528 goto out;
9529 }
9530
9531 __set_bit(res[i].register_op,
9532 ctx->restrictions.register_op);
9533 break;
9534 case IORING_RESTRICTION_SQE_OP:
9535 if (res[i].sqe_op >= IORING_OP_LAST) {
9536 ret = -EINVAL;
9537 goto out;
9538 }
9539
9540 __set_bit(res[i].sqe_op, ctx->restrictions.sqe_op);
9541 break;
9542 case IORING_RESTRICTION_SQE_FLAGS_ALLOWED:
9543 ctx->restrictions.sqe_flags_allowed = res[i].sqe_flags;
9544 break;
9545 case IORING_RESTRICTION_SQE_FLAGS_REQUIRED:
9546 ctx->restrictions.sqe_flags_required = res[i].sqe_flags;
9547 break;
9548 default:
9549 ret = -EINVAL;
9550 goto out;
9551 }
9552 }
9553
9554out:
9555 /* Reset all restrictions if an error happened */
9556 if (ret != 0)
9557 memset(&ctx->restrictions, 0, sizeof(ctx->restrictions));
9558 else
9559 ctx->restrictions.registered = true;
9560
9561 kfree(res);
9562 return ret;
9563}
9564
9565static int io_register_enable_rings(struct io_ring_ctx *ctx)
9566{
9567 if (!(ctx->flags & IORING_SETUP_R_DISABLED))
9568 return -EBADFD;
9569
9570 if (ctx->restrictions.registered)
9571 ctx->restricted = 1;
9572
9573 ctx->flags &= ~IORING_SETUP_R_DISABLED;
9574
9575 io_sq_offload_start(ctx);
9576
9577 return 0;
9578}
9579
9580static bool io_register_op_must_quiesce(int op)
9581{
9582 switch (op) {
9583 case IORING_UNREGISTER_FILES:
9584 case IORING_REGISTER_FILES_UPDATE:
9585 case IORING_REGISTER_PROBE:
9586 case IORING_REGISTER_PERSONALITY:
9587 case IORING_UNREGISTER_PERSONALITY:
9588 return false;
9589 default:
9590 return true;
9591 }
9592}
9593
9594static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
9595 void __user *arg, unsigned nr_args)
9596 __releases(ctx->uring_lock)
9597 __acquires(ctx->uring_lock)
9598{
9599 int ret;
9600
9601 /*
9602 * We're inside the ring mutex, if the ref is already dying, then
9603 * someone else killed the ctx or is already going through
9604 * io_uring_register().
9605 */
9606 if (percpu_ref_is_dying(&ctx->refs))
9607 return -ENXIO;
9608
9609 if (io_register_op_must_quiesce(opcode)) {
9610 percpu_ref_kill(&ctx->refs);
9611
9612 /*
9613 * Drop uring mutex before waiting for references to exit. If
9614 * another thread is currently inside io_uring_enter() it might
9615 * need to grab the uring_lock to make progress. If we hold it
9616 * here across the drain wait, then we can deadlock. It's safe
9617 * to drop the mutex here, since no new references will come in
9618 * after we've killed the percpu ref.
9619 */
9620 mutex_unlock(&ctx->uring_lock);
9621 do {
9622 ret = wait_for_completion_interruptible(&ctx->ref_comp);
9623 if (!ret)
9624 break;
9625 ret = io_run_task_work_sig();
9626 if (ret < 0)
9627 break;
9628 } while (1);
9629
9630 mutex_lock(&ctx->uring_lock);
9631
9632 if (ret) {
9633 percpu_ref_resurrect(&ctx->refs);
9634 goto out_quiesce;
9635 }
9636 }
9637
9638 if (ctx->restricted) {
9639 if (opcode >= IORING_REGISTER_LAST) {
9640 ret = -EINVAL;
9641 goto out;
9642 }
9643
9644 if (!test_bit(opcode, ctx->restrictions.register_op)) {
9645 ret = -EACCES;
9646 goto out;
9647 }
9648 }
9649
9650 switch (opcode) {
9651 case IORING_REGISTER_BUFFERS:
9652 ret = io_sqe_buffer_register(ctx, arg, nr_args);
9653 break;
9654 case IORING_UNREGISTER_BUFFERS:
9655 ret = -EINVAL;
9656 if (arg || nr_args)
9657 break;
9658 ret = io_sqe_buffer_unregister(ctx);
9659 break;
9660 case IORING_REGISTER_FILES:
9661 ret = io_sqe_files_register(ctx, arg, nr_args);
9662 break;
9663 case IORING_UNREGISTER_FILES:
9664 ret = -EINVAL;
9665 if (arg || nr_args)
9666 break;
9667 ret = io_sqe_files_unregister(ctx);
9668 break;
9669 case IORING_REGISTER_FILES_UPDATE:
9670 ret = io_sqe_files_update(ctx, arg, nr_args);
9671 break;
9672 case IORING_REGISTER_EVENTFD:
9673 case IORING_REGISTER_EVENTFD_ASYNC:
9674 ret = -EINVAL;
9675 if (nr_args != 1)
9676 break;
9677 ret = io_eventfd_register(ctx, arg);
9678 if (ret)
9679 break;
9680 if (opcode == IORING_REGISTER_EVENTFD_ASYNC)
9681 ctx->eventfd_async = 1;
9682 else
9683 ctx->eventfd_async = 0;
9684 break;
9685 case IORING_UNREGISTER_EVENTFD:
9686 ret = -EINVAL;
9687 if (arg || nr_args)
9688 break;
9689 ret = io_eventfd_unregister(ctx);
9690 break;
9691 case IORING_REGISTER_PROBE:
9692 ret = -EINVAL;
9693 if (!arg || nr_args > 256)
9694 break;
9695 ret = io_probe(ctx, arg, nr_args);
9696 break;
9697 case IORING_REGISTER_PERSONALITY:
9698 ret = -EINVAL;
9699 if (arg || nr_args)
9700 break;
9701 ret = io_register_personality(ctx);
9702 break;
9703 case IORING_UNREGISTER_PERSONALITY:
9704 ret = -EINVAL;
9705 if (arg)
9706 break;
9707 ret = io_unregister_personality(ctx, nr_args);
9708 break;
9709 case IORING_REGISTER_ENABLE_RINGS:
9710 ret = -EINVAL;
9711 if (arg || nr_args)
9712 break;
9713 ret = io_register_enable_rings(ctx);
9714 break;
9715 case IORING_REGISTER_RESTRICTIONS:
9716 ret = io_register_restrictions(ctx, arg, nr_args);
9717 break;
9718 default:
9719 ret = -EINVAL;
9720 break;
9721 }
9722
9723out:
9724 if (io_register_op_must_quiesce(opcode)) {
9725 /* bring the ctx back to life */
9726 percpu_ref_reinit(&ctx->refs);
9727out_quiesce:
9728 reinit_completion(&ctx->ref_comp);
9729 }
9730 return ret;
9731}
9732
9733SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode,
9734 void __user *, arg, unsigned int, nr_args)
9735{
9736 struct io_ring_ctx *ctx;
9737 long ret = -EBADF;
9738 struct fd f;
9739
9740 f = fdget(fd);
9741 if (!f.file)
9742 return -EBADF;
9743
9744 ret = -EOPNOTSUPP;
9745 if (f.file->f_op != &io_uring_fops)
9746 goto out_fput;
9747
9748 ctx = f.file->private_data;
9749
9750 mutex_lock(&ctx->uring_lock);
9751 ret = __io_uring_register(ctx, opcode, arg, nr_args);
9752 mutex_unlock(&ctx->uring_lock);
9753 trace_io_uring_register(ctx, opcode, ctx->nr_user_files, ctx->nr_user_bufs,
9754 ctx->cq_ev_fd != NULL, ret);
9755out_fput:
9756 fdput(f);
9757 return ret;
9758}
9759
9760static int __init io_uring_init(void)
9761{
9762#define __BUILD_BUG_VERIFY_ELEMENT(stype, eoffset, etype, ename) do { \
9763 BUILD_BUG_ON(offsetof(stype, ename) != eoffset); \
9764 BUILD_BUG_ON(sizeof(etype) != sizeof_field(stype, ename)); \
9765} while (0)
9766
9767#define BUILD_BUG_SQE_ELEM(eoffset, etype, ename) \
9768 __BUILD_BUG_VERIFY_ELEMENT(struct io_uring_sqe, eoffset, etype, ename)
9769 BUILD_BUG_ON(sizeof(struct io_uring_sqe) != 64);
9770 BUILD_BUG_SQE_ELEM(0, __u8, opcode);
9771 BUILD_BUG_SQE_ELEM(1, __u8, flags);
9772 BUILD_BUG_SQE_ELEM(2, __u16, ioprio);
9773 BUILD_BUG_SQE_ELEM(4, __s32, fd);
9774 BUILD_BUG_SQE_ELEM(8, __u64, off);
9775 BUILD_BUG_SQE_ELEM(8, __u64, addr2);
9776 BUILD_BUG_SQE_ELEM(16, __u64, addr);
9777 BUILD_BUG_SQE_ELEM(16, __u64, splice_off_in);
9778 BUILD_BUG_SQE_ELEM(24, __u32, len);
9779 BUILD_BUG_SQE_ELEM(28, __kernel_rwf_t, rw_flags);
9780 BUILD_BUG_SQE_ELEM(28, /* compat */ int, rw_flags);
9781 BUILD_BUG_SQE_ELEM(28, /* compat */ __u32, rw_flags);
9782 BUILD_BUG_SQE_ELEM(28, __u32, fsync_flags);
9783 BUILD_BUG_SQE_ELEM(28, /* compat */ __u16, poll_events);
9784 BUILD_BUG_SQE_ELEM(28, __u32, poll32_events);
9785 BUILD_BUG_SQE_ELEM(28, __u32, sync_range_flags);
9786 BUILD_BUG_SQE_ELEM(28, __u32, msg_flags);
9787 BUILD_BUG_SQE_ELEM(28, __u32, timeout_flags);
9788 BUILD_BUG_SQE_ELEM(28, __u32, accept_flags);
9789 BUILD_BUG_SQE_ELEM(28, __u32, cancel_flags);
9790 BUILD_BUG_SQE_ELEM(28, __u32, open_flags);
9791 BUILD_BUG_SQE_ELEM(28, __u32, statx_flags);
9792 BUILD_BUG_SQE_ELEM(28, __u32, fadvise_advice);
9793 BUILD_BUG_SQE_ELEM(28, __u32, splice_flags);
9794 BUILD_BUG_SQE_ELEM(32, __u64, user_data);
9795 BUILD_BUG_SQE_ELEM(40, __u16, buf_index);
9796 BUILD_BUG_SQE_ELEM(42, __u16, personality);
9797 BUILD_BUG_SQE_ELEM(44, __s32, splice_fd_in);
9798
9799 BUILD_BUG_ON(ARRAY_SIZE(io_op_defs) != IORING_OP_LAST);
9800 BUILD_BUG_ON(__REQ_F_LAST_BIT >= 8 * sizeof(int));
9801 req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC);
9802 return 0;
9803};
9804__initcall(io_uring_init);
Linux 6.x block layer and io_uring tree(s)