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io_uring/rsrc: don't offload node free
[linux-block.git] / io_uring / rsrc.c
CommitLineData
73572984
JA		 1// SPDX-License-Identifier: GPL-2.0
2#include <linux/kernel.h>
3#include <linux/errno.h>
4#include <linux/fs.h>
5#include <linux/file.h>
6#include <linux/mm.h>
7#include <linux/slab.h>
8#include <linux/nospec.h>
9#include <linux/hugetlb.h>
10#include <linux/compat.h>
11#include <linux/io_uring.h>
12
13#include <uapi/linux/io_uring.h>
14
73572984
JA		 15#include "io_uring.h"
16#include "openclose.h"
17#include "rsrc.h"
18
19struct io_rsrc_update {
20 struct file *file;
21 u64 arg;
22 u32 nr_args;
23 u32 offset;
24};
25
26static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
27 struct io_mapped_ubuf **pimu,
28 struct page **last_hpage);
29
73572984
JA		 30/* only define max */
31#define IORING_MAX_FIXED_FILES (1U << 20)
32#define IORING_MAX_REG_BUFFERS (1U << 14)
33
6a9ce66f 34int __io_account_mem(struct user_struct *user, unsigned long nr_pages)
73572984
JA		 35{
36 unsigned long page_limit, cur_pages, new_pages;
37
6a9ce66f
PB		 38 if (!nr_pages)
39 return 0;
40
73572984
JA		 41 /* Don't allow more pages than we can safely lock */
42 page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
43
4ccc6db0 44 cur_pages = atomic_long_read(&user->locked_vm);
73572984 45 do {
73572984
JA		 46 new_pages = cur_pages + nr_pages;
47 if (new_pages > page_limit)
48 return -ENOMEM;
4ccc6db0
UB		 49 } while (!atomic_long_try_cmpxchg(&user->locked_vm,
50 &cur_pages, new_pages));
73572984
JA		 51 return 0;
52}
53
54static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
55{
56 if (ctx->user)
57 __io_unaccount_mem(ctx->user, nr_pages);
58
59 if (ctx->mm_account)
60 atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm);
61}
62
63static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
64{
65 int ret;
66
67 if (ctx->user) {
68 ret = __io_account_mem(ctx->user, nr_pages);
69 if (ret)
70 return ret;
71 }
72
73 if (ctx->mm_account)
74 atomic64_add(nr_pages, &ctx->mm_account->pinned_vm);
75
76 return 0;
77}
78
79static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst,
80 void __user *arg, unsigned index)
81{
82 struct iovec __user *src;
83
84#ifdef CONFIG_COMPAT
85 if (ctx->compat) {
86 struct compat_iovec __user *ciovs;
87 struct compat_iovec ciov;
88
89 ciovs = (struct compat_iovec __user *) arg;
90 if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov)))
91 return -EFAULT;
92
93 dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base);
94 dst->iov_len = ciov.iov_len;
95 return 0;
96 }
97#endif
98 src = (struct iovec __user *) arg;
99 if (copy_from_user(dst, &src[index], sizeof(*dst)))
100 return -EFAULT;
101 return 0;
102}
103
104static int io_buffer_validate(struct iovec *iov)
105{
106 unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1);
107
108 /*
109 * Don't impose further limits on the size and buffer
110 * constraints here, we'll -EINVAL later when IO is
111 * submitted if they are wrong.
112 */
113 if (!iov->iov_base)
114 return iov->iov_len ? -EFAULT : 0;
115 if (!iov->iov_len)
116 return -EFAULT;
117
118 /* arbitrary limit, but we need something */
119 if (iov->iov_len > SZ_1G)
120 return -EFAULT;
121
122 if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp))
123 return -EOVERFLOW;
124
125 return 0;
126}
127
128static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot)
129{
130 struct io_mapped_ubuf *imu = *slot;
131 unsigned int i;
132
133 if (imu != ctx->dummy_ubuf) {
134 for (i = 0; i < imu->nr_bvecs; i++)
135 unpin_user_page(imu->bvec[i].bv_page);
136 if (imu->acct_pages)
137 io_unaccount_mem(ctx, imu->acct_pages);
138 kvfree(imu);
139 }
140 *slot = NULL;
141}
142
ff7c75ec
PB		 143static void io_rsrc_put_work_one(struct io_rsrc_data *rsrc_data,
144 struct io_rsrc_put *prsrc)
145{
146 struct io_ring_ctx *ctx = rsrc_data->ctx;
147
36b9818a
PB		 148 if (prsrc->tag)
149 io_post_aux_cqe(ctx, prsrc->tag, 0, 0);
ff7c75ec
PB		 150 rsrc_data->do_put(ctx, prsrc);
151}
152
73572984
JA		 153static void __io_rsrc_put_work(struct io_rsrc_node *ref_node)
154{
155 struct io_rsrc_data *rsrc_data = ref_node->rsrc_data;
73572984
JA		 156 struct io_rsrc_put *prsrc, *tmp;
157
ff7c75ec
PB		 158 if (ref_node->inline_items)
159 io_rsrc_put_work_one(rsrc_data, &ref_node->item);
160
c824986c 161 list_for_each_entry_safe(prsrc, tmp, &ref_node->item_list, list) {
73572984 162 list_del(&prsrc->list);
ff7c75ec 163 io_rsrc_put_work_one(rsrc_data, prsrc);
73572984
JA		 164 kfree(prsrc);
165 }
166
167 io_rsrc_node_destroy(ref_node);
168 if (atomic_dec_and_test(&rsrc_data->refs))
169 complete(&rsrc_data->done);
170}
171
73572984
JA		 172void io_wait_rsrc_data(struct io_rsrc_data *data)
173{
174 if (data && !atomic_dec_and_test(&data->refs))
175 wait_for_completion(&data->done);
176}
177
178void io_rsrc_node_destroy(struct io_rsrc_node *ref_node)
179{
73572984
JA		 180 kfree(ref_node);
181}
182
ef8ae64f
PB		 183void io_rsrc_node_ref_zero(struct io_rsrc_node *node)
184 __must_hold(&node->rsrc_data->ctx->uring_lock)
73572984 185{
73572984 186 struct io_ring_ctx *ctx = node->rsrc_data->ctx;
73572984 187
73572984 188 node->done = true;
73572984
JA		 189 while (!list_empty(&ctx->rsrc_ref_list)) {
190 node = list_first_entry(&ctx->rsrc_ref_list,
191 struct io_rsrc_node, node);
192 /* recycle ref nodes in order */
193 if (!node->done)
194 break;
73572984 195
36b9818a
PB		 196 list_del(&node->node);
197 __io_rsrc_put_work(node);
d34b1b0b 198 }
73572984
JA		 199}
200
201static struct io_rsrc_node *io_rsrc_node_alloc(void)
202{
203 struct io_rsrc_node *ref_node;
204
205 ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
206 if (!ref_node)
207 return NULL;
208
ef8ae64f 209 ref_node->refs = 1;
73572984 210 INIT_LIST_HEAD(&ref_node->node);
c824986c 211 INIT_LIST_HEAD(&ref_node->item_list);
73572984 212 ref_node->done = false;
ff7c75ec 213 ref_node->inline_items = 0;
73572984
JA		 214 return ref_node;
215}
216
217void io_rsrc_node_switch(struct io_ring_ctx *ctx,
218 struct io_rsrc_data *data_to_kill)
219 __must_hold(&ctx->uring_lock)
220{
221 WARN_ON_ONCE(!ctx->rsrc_backup_node);
222 WARN_ON_ONCE(data_to_kill && !ctx->rsrc_node);
223
73572984
JA		 224 if (data_to_kill) {
225 struct io_rsrc_node *rsrc_node = ctx->rsrc_node;
226
227 rsrc_node->rsrc_data = data_to_kill;
73572984 228 list_add_tail(&rsrc_node->node, &ctx->rsrc_ref_list);
73572984
JA		 229
230 atomic_inc(&data_to_kill->refs);
b8fb5b4f 231 /* put master ref */
ef8ae64f 232 io_put_rsrc_node(rsrc_node);
73572984
JA		 233 ctx->rsrc_node = NULL;
234 }
235
236 if (!ctx->rsrc_node) {
237 ctx->rsrc_node = ctx->rsrc_backup_node;
238 ctx->rsrc_backup_node = NULL;
239 }
240}
241
242int io_rsrc_node_switch_start(struct io_ring_ctx *ctx)
243{
244 if (ctx->rsrc_backup_node)
245 return 0;
246 ctx->rsrc_backup_node = io_rsrc_node_alloc();
247 return ctx->rsrc_backup_node ? 0 : -ENOMEM;
248}
249
250__cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
251 struct io_ring_ctx *ctx)
252{
253 int ret;
254
255 /* As we may drop ->uring_lock, other task may have started quiesce */
256 if (data->quiesce)
257 return -ENXIO;
77e3202a
PB		 258 ret = io_rsrc_node_switch_start(ctx);
259 if (ret)
260 return ret;
261 io_rsrc_node_switch(ctx, data);
262
263 /* kill initial ref, already quiesced if zero */
264 if (atomic_dec_and_test(&data->refs))
265 return 0;
73572984
JA		 266
267 data->quiesce = true;
77e3202a 268 mutex_unlock(&ctx->uring_lock);
73572984 269 do {
ef67fcb4 270 ret = io_run_task_work_sig(ctx);
77e3202a
PB		 271 if (ret < 0) {
272 atomic_inc(&data->refs);
273 /* wait for all works potentially completing data->done */
77e3202a
PB		 274 reinit_completion(&data->done);
275 mutex_lock(&ctx->uring_lock);
276 break;
277 }
ef67fcb4 278
73572984
JA		 279 ret = wait_for_completion_interruptible(&data->done);
280 if (!ret) {
281 mutex_lock(&ctx->uring_lock);
0ced756f 282 if (atomic_read(&data->refs) <= 0)
73572984 283 break;
0ced756f
PB		 284 /*
285 * it has been revived by another thread while
286 * we were unlocked
287 */
288 mutex_unlock(&ctx->uring_lock);
73572984 289 }
77e3202a 290 } while (1);
73572984
JA		 291 data->quiesce = false;
292
293 return ret;
294}
295
296static void io_free_page_table(void **table, size_t size)
297{
298 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
299
300 for (i = 0; i < nr_tables; i++)
301 kfree(table[i]);
302 kfree(table);
303}
304
305static void io_rsrc_data_free(struct io_rsrc_data *data)
306{
307 size_t size = data->nr * sizeof(data->tags[0][0]);
308
309 if (data->tags)
310 io_free_page_table((void **)data->tags, size);
311 kfree(data);
312}
313
314static __cold void **io_alloc_page_table(size_t size)
315{
316 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
317 size_t init_size = size;
318 void **table;
319
320 table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL_ACCOUNT);
321 if (!table)
322 return NULL;
323
324 for (i = 0; i < nr_tables; i++) {
325 unsigned int this_size = min_t(size_t, size, PAGE_SIZE);
326
327 table[i] = kzalloc(this_size, GFP_KERNEL_ACCOUNT);
328 if (!table[i]) {
329 io_free_page_table(table, init_size);
330 return NULL;
331 }
332 size -= this_size;
333 }
334 return table;
335}
336
337__cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx,
338 rsrc_put_fn *do_put, u64 __user *utags,
339 unsigned nr, struct io_rsrc_data **pdata)
340{
341 struct io_rsrc_data *data;
6acd352d 342 int ret = 0;
73572984
JA		 343 unsigned i;
344
345 data = kzalloc(sizeof(*data), GFP_KERNEL);
346 if (!data)
347 return -ENOMEM;
348 data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0]));
349 if (!data->tags) {
350 kfree(data);
351 return -ENOMEM;
352 }
353
354 data->nr = nr;
355 data->ctx = ctx;
356 data->do_put = do_put;
357 if (utags) {
358 ret = -EFAULT;
359 for (i = 0; i < nr; i++) {
360 u64 *tag_slot = io_get_tag_slot(data, i);
361
362 if (copy_from_user(tag_slot, &utags[i],
363 sizeof(*tag_slot)))
364 goto fail;
365 }
366 }
367
368 atomic_set(&data->refs, 1);
369 init_completion(&data->done);
370 *pdata = data;
371 return 0;
372fail:
373 io_rsrc_data_free(data);
374 return ret;
375}
376
377static int __io_sqe_files_update(struct io_ring_ctx *ctx,
378 struct io_uring_rsrc_update2 *up,
379 unsigned nr_args)
380{
381 u64 __user *tags = u64_to_user_ptr(up->tags);
382 __s32 __user *fds = u64_to_user_ptr(up->data);
383 struct io_rsrc_data *data = ctx->file_data;
384 struct io_fixed_file *file_slot;
385 struct file *file;
386 int fd, i, err = 0;
387 unsigned int done;
388 bool needs_switch = false;
389
390 if (!ctx->file_data)
391 return -ENXIO;
392 if (up->offset + nr_args > ctx->nr_user_files)
393 return -EINVAL;
394
395 for (done = 0; done < nr_args; done++) {
396 u64 tag = 0;
397
398 if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) ||
399 copy_from_user(&fd, &fds[done], sizeof(fd))) {
400 err = -EFAULT;
401 break;
402 }
403 if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) {
404 err = -EINVAL;
405 break;
406 }
407 if (fd == IORING_REGISTER_FILES_SKIP)
408 continue;
409
410 i = array_index_nospec(up->offset + done, ctx->nr_user_files);
411 file_slot = io_fixed_file_slot(&ctx->file_table, i);
412
413 if (file_slot->file_ptr) {
414 file = (struct file *)(file_slot->file_ptr & FFS_MASK);
415 err = io_queue_rsrc_removal(data, i, ctx->rsrc_node, file);
416 if (err)
417 break;
418 file_slot->file_ptr = 0;
419 io_file_bitmap_clear(&ctx->file_table, i);
420 needs_switch = true;
421 }
422 if (fd != -1) {
423 file = fget(fd);
424 if (!file) {
425 err = -EBADF;
426 break;
427 }
428 /*
429 * Don't allow io_uring instances to be registered. If
430 * UNIX isn't enabled, then this causes a reference
431 * cycle and this instance can never get freed. If UNIX
432 * is enabled we'll handle it just fine, but there's
433 * still no point in allowing a ring fd as it doesn't
434 * support regular read/write anyway.
435 */
436 if (io_is_uring_fops(file)) {
437 fput(file);
438 err = -EBADF;
439 break;
440 }
441 err = io_scm_file_account(ctx, file);
442 if (err) {
443 fput(file);
444 break;
445 }
446 *io_get_tag_slot(data, i) = tag;
447 io_fixed_file_set(file_slot, file);
448 io_file_bitmap_set(&ctx->file_table, i);
449 }
450 }
451
452 if (needs_switch)
453 io_rsrc_node_switch(ctx, data);
454 return done ? done : err;
455}
456
457static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
458 struct io_uring_rsrc_update2 *up,
459 unsigned int nr_args)
460{
461 u64 __user *tags = u64_to_user_ptr(up->tags);
462 struct iovec iov, __user *iovs = u64_to_user_ptr(up->data);
463 struct page *last_hpage = NULL;
464 bool needs_switch = false;
465 __u32 done;
466 int i, err;
467
468 if (!ctx->buf_data)
469 return -ENXIO;
470 if (up->offset + nr_args > ctx->nr_user_bufs)
471 return -EINVAL;
472
473 for (done = 0; done < nr_args; done++) {
474 struct io_mapped_ubuf *imu;
475 int offset = up->offset + done;
476 u64 tag = 0;
477
478 err = io_copy_iov(ctx, &iov, iovs, done);
479 if (err)
480 break;
481 if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) {
482 err = -EFAULT;
483 break;
484 }
485 err = io_buffer_validate(&iov);
486 if (err)
487 break;
488 if (!iov.iov_base && tag) {
489 err = -EINVAL;
490 break;
491 }
492 err = io_sqe_buffer_register(ctx, &iov, &imu, &last_hpage);
493 if (err)
494 break;
495
496 i = array_index_nospec(offset, ctx->nr_user_bufs);
497 if (ctx->user_bufs[i] != ctx->dummy_ubuf) {
498 err = io_queue_rsrc_removal(ctx->buf_data, i,
499 ctx->rsrc_node, ctx->user_bufs[i]);
500 if (unlikely(err)) {
501 io_buffer_unmap(ctx, &imu);
502 break;
503 }
5ff4fdff 504 ctx->user_bufs[i] = ctx->dummy_ubuf;
73572984
JA		 505 needs_switch = true;
506 }
507
508 ctx->user_bufs[i] = imu;
509 *io_get_tag_slot(ctx->buf_data, offset) = tag;
510 }
511
512 if (needs_switch)
513 io_rsrc_node_switch(ctx, ctx->buf_data);
514 return done ? done : err;
515}
516
517static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
518 struct io_uring_rsrc_update2 *up,
519 unsigned nr_args)
520{
521 __u32 tmp;
522 int err;
523
524 if (check_add_overflow(up->offset, nr_args, &tmp))
525 return -EOVERFLOW;
526 err = io_rsrc_node_switch_start(ctx);
527 if (err)
528 return err;
529
530 switch (type) {
531 case IORING_RSRC_FILE:
532 return __io_sqe_files_update(ctx, up, nr_args);
533 case IORING_RSRC_BUFFER:
534 return __io_sqe_buffers_update(ctx, up, nr_args);
535 }
536 return -EINVAL;
537}
538
539int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg,
540 unsigned nr_args)
541{
542 struct io_uring_rsrc_update2 up;
543
544 if (!nr_args)
545 return -EINVAL;
546 memset(&up, 0, sizeof(up));
547 if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update)))
548 return -EFAULT;
549 if (up.resv || up.resv2)
550 return -EINVAL;
551 return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args);
552}
553
554int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg,
555 unsigned size, unsigned type)
556{
557 struct io_uring_rsrc_update2 up;
558
559 if (size != sizeof(up))
560 return -EINVAL;
561 if (copy_from_user(&up, arg, sizeof(up)))
562 return -EFAULT;
563 if (!up.nr || up.resv || up.resv2)
564 return -EINVAL;
565 return __io_register_rsrc_update(ctx, type, &up, up.nr);
566}
567
568__cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
569 unsigned int size, unsigned int type)
570{
571 struct io_uring_rsrc_register rr;
572
573 /* keep it extendible */
574 if (size != sizeof(rr))
575 return -EINVAL;
576
577 memset(&rr, 0, sizeof(rr));
578 if (copy_from_user(&rr, arg, size))
579 return -EFAULT;
580 if (!rr.nr || rr.resv2)
581 return -EINVAL;
582 if (rr.flags & ~IORING_RSRC_REGISTER_SPARSE)
583 return -EINVAL;
584
585 switch (type) {
586 case IORING_RSRC_FILE:
587 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
588 break;
589 return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data),
590 rr.nr, u64_to_user_ptr(rr.tags));
591 case IORING_RSRC_BUFFER:
592 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
593 break;
594 return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data),
595 rr.nr, u64_to_user_ptr(rr.tags));
596 }
597 return -EINVAL;
598}
599
d9808ceb 600int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
73572984 601{
f2ccb5ae 602 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
73572984
JA		 603
604 if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
605 return -EINVAL;
606 if (sqe->rw_flags || sqe->splice_fd_in)
607 return -EINVAL;
608
609 up->offset = READ_ONCE(sqe->off);
610 up->nr_args = READ_ONCE(sqe->len);
611 if (!up->nr_args)
612 return -EINVAL;
613 up->arg = READ_ONCE(sqe->addr);
614 return 0;
615}
616
617static int io_files_update_with_index_alloc(struct io_kiocb *req,
618 unsigned int issue_flags)
619{
f2ccb5ae 620 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
73572984
JA		 621 __s32 __user *fds = u64_to_user_ptr(up->arg);
622 unsigned int done;
623 struct file *file;
624 int ret, fd;
625
626 if (!req->ctx->file_data)
627 return -ENXIO;
628
629 for (done = 0; done < up->nr_args; done++) {
630 if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
631 ret = -EFAULT;
632 break;
633 }
634
635 file = fget(fd);
636 if (!file) {
637 ret = -EBADF;
638 break;
639 }
640 ret = io_fixed_fd_install(req, issue_flags, file,
641 IORING_FILE_INDEX_ALLOC);
642 if (ret < 0)
643 break;
644 if (copy_to_user(&fds[done], &ret, sizeof(ret))) {
f110ed84 645 __io_close_fixed(req->ctx, issue_flags, ret);
73572984
JA		 646 ret = -EFAULT;
647 break;
648 }
649 }
650
651 if (done)
652 return done;
653 return ret;
654}
655
d9808ceb 656int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
73572984 657{
f2ccb5ae 658 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
73572984
JA		 659 struct io_ring_ctx *ctx = req->ctx;
660 struct io_uring_rsrc_update2 up2;
661 int ret;
662
663 up2.offset = up->offset;
664 up2.data = up->arg;
665 up2.nr = 0;
666 up2.tags = 0;
667 up2.resv = 0;
668 up2.resv2 = 0;
669
670 if (up->offset == IORING_FILE_INDEX_ALLOC) {
671 ret = io_files_update_with_index_alloc(req, issue_flags);
672 } else {
673 io_ring_submit_lock(ctx, issue_flags);
674 ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE,
675 &up2, up->nr_args);
676 io_ring_submit_unlock(ctx, issue_flags);
677 }
678
679 if (ret < 0)
680 req_set_fail(req);
681 io_req_set_res(req, ret, 0);
682 return IOU_OK;
683}
684
685int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx,
686 struct io_rsrc_node *node, void *rsrc)
687{
688 u64 *tag_slot = io_get_tag_slot(data, idx);
689 struct io_rsrc_put *prsrc;
ff7c75ec 690 bool inline_item = true;
73572984 691
ff7c75ec
PB		 692 if (!node->inline_items) {
693 prsrc = &node->item;
694 node->inline_items++;
695 } else {
696 prsrc = kzalloc(sizeof(*prsrc), GFP_KERNEL);
697 if (!prsrc)
698 return -ENOMEM;
699 inline_item = false;
700 }
73572984
JA		 701
702 prsrc->tag = *tag_slot;
703 *tag_slot = 0;
704 prsrc->rsrc = rsrc;
ff7c75ec
PB		 705 if (!inline_item)
706 list_add(&prsrc->list, &node->item_list);
73572984
JA		 707 return 0;
708}
709
710void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
711{
73572984
JA		 712 int i;
713
714 for (i = 0; i < ctx->nr_user_files; i++) {
715 struct file *file = io_file_from_index(&ctx->file_table, i);
716
38eddb2c
PB		 717 /* skip scm accounted files, they'll be freed by ->ring_sock */
718 if (!file || io_file_need_scm(file))
73572984
JA		 719 continue;
720 io_file_bitmap_clear(&ctx->file_table, i);
721 fput(file);
722 }
73572984
JA		 723
724#if defined(CONFIG_UNIX)
725 if (ctx->ring_sock) {
726 struct sock *sock = ctx->ring_sock->sk;
727 struct sk_buff *skb;
728
729 while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL)
730 kfree_skb(skb);
731 }
732#endif
733 io_free_file_tables(&ctx->file_table);
02a4d923 734 io_file_table_set_alloc_range(ctx, 0, 0);
73572984
JA		 735 io_rsrc_data_free(ctx->file_data);
736 ctx->file_data = NULL;
737 ctx->nr_user_files = 0;
738}
739
740int io_sqe_files_unregister(struct io_ring_ctx *ctx)
741{
742 unsigned nr = ctx->nr_user_files;
743 int ret;
744
745 if (!ctx->file_data)
746 return -ENXIO;
747
748 /*
749 * Quiesce may unlock ->uring_lock, and while it's not held
750 * prevent new requests using the table.
751 */
752 ctx->nr_user_files = 0;
753 ret = io_rsrc_ref_quiesce(ctx->file_data, ctx);
754 ctx->nr_user_files = nr;
755 if (!ret)
756 __io_sqe_files_unregister(ctx);
757 return ret;
758}
759
760/*
761 * Ensure the UNIX gc is aware of our file set, so we are certain that
762 * the io_uring can be safely unregistered on process exit, even if we have
763 * loops in the file referencing. We account only files that can hold other
764 * files because otherwise they can't form a loop and so are not interesting
765 * for GC.
766 */
767int __io_scm_file_account(struct io_ring_ctx *ctx, struct file *file)
768{
769#if defined(CONFIG_UNIX)
770 struct sock *sk = ctx->ring_sock->sk;
771 struct sk_buff_head *head = &sk->sk_receive_queue;
772 struct scm_fp_list *fpl;
773 struct sk_buff *skb;
774
775 if (likely(!io_file_need_scm(file)))
776 return 0;
777
778 /*
779 * See if we can merge this file into an existing skb SCM_RIGHTS
780 * file set. If there's no room, fall back to allocating a new skb
781 * and filling it in.
782 */
783 spin_lock_irq(&head->lock);
784 skb = skb_peek(head);
785 if (skb && UNIXCB(skb).fp->count < SCM_MAX_FD)
786 __skb_unlink(skb, head);
787 else
788 skb = NULL;
789 spin_unlock_irq(&head->lock);
790
791 if (!skb) {
792 fpl = kzalloc(sizeof(*fpl), GFP_KERNEL);
793 if (!fpl)
794 return -ENOMEM;
795
796 skb = alloc_skb(0, GFP_KERNEL);
797 if (!skb) {
798 kfree(fpl);
799 return -ENOMEM;
800 }
801
802 fpl->user = get_uid(current_user());
803 fpl->max = SCM_MAX_FD;
804 fpl->count = 0;
805
806 UNIXCB(skb).fp = fpl;
807 skb->sk = sk;
0091bfc8 808 skb->scm_io_uring = 1;
73572984
JA		 809 skb->destructor = unix_destruct_scm;
810 refcount_add(skb->truesize, &sk->sk_wmem_alloc);
811 }
812
813 fpl = UNIXCB(skb).fp;
814 fpl->fp[fpl->count++] = get_file(file);
815 unix_inflight(fpl->user, file);
816 skb_queue_head(head, skb);
817 fput(file);
818#endif
819 return 0;
820}
821
822static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
823{
824 struct file *file = prsrc->file;
825#if defined(CONFIG_UNIX)
826 struct sock *sock = ctx->ring_sock->sk;
827 struct sk_buff_head list, *head = &sock->sk_receive_queue;
828 struct sk_buff *skb;
829 int i;
830
831 if (!io_file_need_scm(file)) {
832 fput(file);
833 return;
834 }
835
836 __skb_queue_head_init(&list);
837
838 /*
839 * Find the skb that holds this file in its SCM_RIGHTS. When found,
840 * remove this entry and rearrange the file array.
841 */
842 skb = skb_dequeue(head);
843 while (skb) {
844 struct scm_fp_list *fp;
845
846 fp = UNIXCB(skb).fp;
847 for (i = 0; i < fp->count; i++) {
848 int left;
849
850 if (fp->fp[i] != file)
851 continue;
852
853 unix_notinflight(fp->user, fp->fp[i]);
854 left = fp->count - 1 - i;
855 if (left) {
856 memmove(&fp->fp[i], &fp->fp[i + 1],
857 left * sizeof(struct file *));
858 }
859 fp->count--;
860 if (!fp->count) {
861 kfree_skb(skb);
862 skb = NULL;
863 } else {
864 __skb_queue_tail(&list, skb);
865 }
866 fput(file);
867 file = NULL;
868 break;
869 }
870
871 if (!file)
872 break;
873
874 __skb_queue_tail(&list, skb);
875
876 skb = skb_dequeue(head);
877 }
878
879 if (skb_peek(&list)) {
880 spin_lock_irq(&head->lock);
881 while ((skb = __skb_dequeue(&list)) != NULL)
882 __skb_queue_tail(head, skb);
883 spin_unlock_irq(&head->lock);
884 }
885#else
886 fput(file);
887#endif
888}
889
890int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
891 unsigned nr_args, u64 __user *tags)
892{
893 __s32 __user *fds = (__s32 __user *) arg;
894 struct file *file;
895 int fd, ret;
896 unsigned i;
897
898 if (ctx->file_data)
899 return -EBUSY;
900 if (!nr_args)
901 return -EINVAL;
902 if (nr_args > IORING_MAX_FIXED_FILES)
903 return -EMFILE;
904 if (nr_args > rlimit(RLIMIT_NOFILE))
905 return -EMFILE;
906 ret = io_rsrc_node_switch_start(ctx);
907 if (ret)
908 return ret;
909 ret = io_rsrc_data_alloc(ctx, io_rsrc_file_put, tags, nr_args,
910 &ctx->file_data);
911 if (ret)
912 return ret;
913
914 if (!io_alloc_file_tables(&ctx->file_table, nr_args)) {
915 io_rsrc_data_free(ctx->file_data);
916 ctx->file_data = NULL;
917 return -ENOMEM;
918 }
919
920 for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
921 struct io_fixed_file *file_slot;
922
923 if (fds && copy_from_user(&fd, &fds[i], sizeof(fd))) {
924 ret = -EFAULT;
925 goto fail;
926 }
927 /* allow sparse sets */
928 if (!fds || fd == -1) {
929 ret = -EINVAL;
930 if (unlikely(*io_get_tag_slot(ctx->file_data, i)))
931 goto fail;
932 continue;
933 }
934
935 file = fget(fd);
936 ret = -EBADF;
937 if (unlikely(!file))
938 goto fail;
939
940 /*
941 * Don't allow io_uring instances to be registered. If UNIX
942 * isn't enabled, then this causes a reference cycle and this
943 * instance can never get freed. If UNIX is enabled we'll
944 * handle it just fine, but there's still no point in allowing
945 * a ring fd as it doesn't support regular read/write anyway.
946 */
947 if (io_is_uring_fops(file)) {
948 fput(file);
949 goto fail;
950 }
951 ret = io_scm_file_account(ctx, file);
952 if (ret) {
953 fput(file);
954 goto fail;
955 }
956 file_slot = io_fixed_file_slot(&ctx->file_table, i);
957 io_fixed_file_set(file_slot, file);
958 io_file_bitmap_set(&ctx->file_table, i);
959 }
960
6e73dffb
PB		 961 /* default it to the whole table */
962 io_file_table_set_alloc_range(ctx, 0, ctx->nr_user_files);
73572984
JA		 963 io_rsrc_node_switch(ctx, NULL);
964 return 0;
965fail:
966 __io_sqe_files_unregister(ctx);
967 return ret;
968}
969
970static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
971{
972 io_buffer_unmap(ctx, &prsrc->buf);
973 prsrc->buf = NULL;
974}
975
976void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
977{
978 unsigned int i;
979
980 for (i = 0; i < ctx->nr_user_bufs; i++)
981 io_buffer_unmap(ctx, &ctx->user_bufs[i]);
982 kfree(ctx->user_bufs);
983 io_rsrc_data_free(ctx->buf_data);
984 ctx->user_bufs = NULL;
985 ctx->buf_data = NULL;
986 ctx->nr_user_bufs = 0;
987}
988
989int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
990{
991 unsigned nr = ctx->nr_user_bufs;
992 int ret;
993
994 if (!ctx->buf_data)
995 return -ENXIO;
996
997 /*
998 * Quiesce may unlock ->uring_lock, and while it's not held
999 * prevent new requests using the table.
1000 */
1001 ctx->nr_user_bufs = 0;
1002 ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx);
1003 ctx->nr_user_bufs = nr;
1004 if (!ret)
1005 __io_sqe_buffers_unregister(ctx);
1006 return ret;
1007}
1008
1009/*
1010 * Not super efficient, but this is just a registration time. And we do cache
1011 * the last compound head, so generally we'll only do a full search if we don't
1012 * match that one.
1013 *
1014 * We check if the given compound head page has already been accounted, to
1015 * avoid double accounting it. This allows us to account the full size of the
1016 * page, not just the constituent pages of a huge page.
1017 */
1018static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
1019 int nr_pages, struct page *hpage)
1020{
1021 int i, j;
1022
1023 /* check current page array */
1024 for (i = 0; i < nr_pages; i++) {
1025 if (!PageCompound(pages[i]))
1026 continue;
1027 if (compound_head(pages[i]) == hpage)
1028 return true;
1029 }
1030
1031 /* check previously registered pages */
1032 for (i = 0; i < ctx->nr_user_bufs; i++) {
1033 struct io_mapped_ubuf *imu = ctx->user_bufs[i];
1034
1035 for (j = 0; j < imu->nr_bvecs; j++) {
1036 if (!PageCompound(imu->bvec[j].bv_page))
1037 continue;
1038 if (compound_head(imu->bvec[j].bv_page) == hpage)
1039 return true;
1040 }
1041 }
1042
1043 return false;
1044}
1045
1046static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
1047 int nr_pages, struct io_mapped_ubuf *imu,
1048 struct page **last_hpage)
1049{
1050 int i, ret;
1051
1052 imu->acct_pages = 0;
1053 for (i = 0; i < nr_pages; i++) {
1054 if (!PageCompound(pages[i])) {
1055 imu->acct_pages++;
1056 } else {
1057 struct page *hpage;
1058
1059 hpage = compound_head(pages[i]);
1060 if (hpage == *last_hpage)
1061 continue;
1062 *last_hpage = hpage;
1063 if (headpage_already_acct(ctx, pages, i, hpage))
1064 continue;
1065 imu->acct_pages += page_size(hpage) >> PAGE_SHIFT;
1066 }
1067 }
1068
1069 if (!imu->acct_pages)
1070 return 0;
1071
1072 ret = io_account_mem(ctx, imu->acct_pages);
1073 if (ret)
1074 imu->acct_pages = 0;
1075 return ret;
1076}
1077
1078struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages)
1079{
1080 unsigned long start, end, nr_pages;
1081 struct vm_area_struct **vmas = NULL;
1082 struct page **pages = NULL;
1083 int i, pret, ret = -ENOMEM;
1084
1085 end = (ubuf + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1086 start = ubuf >> PAGE_SHIFT;
1087 nr_pages = end - start;
1088
1089 pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL);
1090 if (!pages)
1091 goto done;
1092
1093 vmas = kvmalloc_array(nr_pages, sizeof(struct vm_area_struct *),
1094 GFP_KERNEL);
1095 if (!vmas)
1096 goto done;
1097
1098 ret = 0;
1099 mmap_read_lock(current->mm);
1100 pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
1101 pages, vmas);
1102 if (pret == nr_pages) {
edd47826
PB		 1103 struct file *file = vmas[0]->vm_file;
1104
73572984
JA		 1105 /* don't support file backed memory */
1106 for (i = 0; i < nr_pages; i++) {
edd47826
PB		 1107 if (vmas[i]->vm_file != file) {
1108 ret = -EINVAL;
1109 break;
1110 }
1111 if (!file)
73572984 1112 continue;
edd47826 1113 if (!vma_is_shmem(vmas[i]) && !is_file_hugepages(file)) {
73572984
JA		 1114 ret = -EOPNOTSUPP;
1115 break;
1116 }
1117 }
1118 *npages = nr_pages;
1119 } else {
1120 ret = pret < 0 ? pret : -EFAULT;
1121 }
1122 mmap_read_unlock(current->mm);
1123 if (ret) {
1124 /*
1125 * if we did partial map, or found file backed vmas,
1126 * release any pages we did get
1127 */
1128 if (pret > 0)
1129 unpin_user_pages(pages, pret);
1130 goto done;
1131 }
1132 ret = 0;
1133done:
1134 kvfree(vmas);
1135 if (ret < 0) {
1136 kvfree(pages);
1137 pages = ERR_PTR(ret);
1138 }
1139 return pages;
1140}
1141
1142static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
1143 struct io_mapped_ubuf **pimu,
1144 struct page **last_hpage)
1145{
1146 struct io_mapped_ubuf *imu = NULL;
1147 struct page **pages = NULL;
1148 unsigned long off;
1149 size_t size;
1150 int ret, nr_pages, i;
977bc873 1151 struct folio *folio = NULL;
73572984 1152
5ff4fdff
PB		 1153 *pimu = ctx->dummy_ubuf;
1154 if (!iov->iov_base)
73572984 1155 return 0;
73572984 1156
73572984 1157 ret = -ENOMEM;
73572984
JA		 1158 pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len,
1159 &nr_pages);
1160 if (IS_ERR(pages)) {
1161 ret = PTR_ERR(pages);
1162 pages = NULL;
1163 goto done;
1164 }
1165
57bebf80
PB		 1166 /* If it's a huge page, try to coalesce them into a single bvec entry */
1167 if (nr_pages > 1) {
1168 folio = page_folio(pages[0]);
1169 for (i = 1; i < nr_pages; i++) {
1170 if (page_folio(pages[i]) != folio) {
1171 folio = NULL;
1172 break;
1173 }
1174 }
1175 if (folio) {
d2acf789
PB		 1176 /*
1177 * The pages are bound to the folio, it doesn't
1178 * actually unpin them but drops all but one reference,
1179 * which is usually put down by io_buffer_unmap().
1180 * Note, needs a better helper.
1181 */
1182 unpin_user_pages(&pages[1], nr_pages - 1);
57bebf80
PB		 1183 nr_pages = 1;
1184 }
1185 }
1186
73572984
JA		 1187 imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL);
1188 if (!imu)
1189 goto done;
1190
1191 ret = io_buffer_account_pin(ctx, pages, nr_pages, imu, last_hpage);
1192 if (ret) {
1193 unpin_user_pages(pages, nr_pages);
1194 goto done;
1195 }
1196
1197 off = (unsigned long) iov->iov_base & ~PAGE_MASK;
1198 size = iov->iov_len;
57bebf80
PB		 1199 /* store original address for later verification */
1200 imu->ubuf = (unsigned long) iov->iov_base;
1201 imu->ubuf_end = imu->ubuf + iov->iov_len;
1202 imu->nr_bvecs = nr_pages;
1203 *pimu = imu;
1204 ret = 0;
1205
1206 if (folio) {
1207 bvec_set_page(&imu->bvec[0], pages[0], size, off);
1208 goto done;
1209 }
73572984
JA		 1210 for (i = 0; i < nr_pages; i++) {
1211 size_t vec_len;
1212
1213 vec_len = min_t(size_t, size, PAGE_SIZE - off);
cc342a21 1214 bvec_set_page(&imu->bvec[i], pages[i], vec_len, off);
73572984
JA		 1215 off = 0;
1216 size -= vec_len;
1217 }
73572984
JA		 1218done:
1219 if (ret)
1220 kvfree(imu);
1221 kvfree(pages);
1222 return ret;
1223}
1224
1225static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args)
1226{
1227 ctx->user_bufs = kcalloc(nr_args, sizeof(*ctx->user_bufs), GFP_KERNEL);
1228 return ctx->user_bufs ? 0 : -ENOMEM;
1229}
1230
1231int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
1232 unsigned int nr_args, u64 __user *tags)
1233{
1234 struct page *last_hpage = NULL;
1235 struct io_rsrc_data *data;
1236 int i, ret;
1237 struct iovec iov;
1238
1239 BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16));
1240
1241 if (ctx->user_bufs)
1242 return -EBUSY;
1243 if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS)
1244 return -EINVAL;
1245 ret = io_rsrc_node_switch_start(ctx);
1246 if (ret)
1247 return ret;
1248 ret = io_rsrc_data_alloc(ctx, io_rsrc_buf_put, tags, nr_args, &data);
1249 if (ret)
1250 return ret;
1251 ret = io_buffers_map_alloc(ctx, nr_args);
1252 if (ret) {
1253 io_rsrc_data_free(data);
1254 return ret;
1255 }
1256
1257 for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) {
1258 if (arg) {
1259 ret = io_copy_iov(ctx, &iov, arg, i);
1260 if (ret)
1261 break;
1262 ret = io_buffer_validate(&iov);
1263 if (ret)
1264 break;
1265 } else {
1266 memset(&iov, 0, sizeof(iov));
1267 }
1268
1269 if (!iov.iov_base && *io_get_tag_slot(data, i)) {
1270 ret = -EINVAL;
1271 break;
1272 }
1273
1274 ret = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i],
1275 &last_hpage);
1276 if (ret)
1277 break;
1278 }
1279
1280 WARN_ON_ONCE(ctx->buf_data);
1281
1282 ctx->buf_data = data;
1283 if (ret)
1284 __io_sqe_buffers_unregister(ctx);
1285 else
1286 io_rsrc_node_switch(ctx, NULL);
1287 return ret;
1288}
c059f785
PB		 1289
1290int io_import_fixed(int ddir, struct iov_iter *iter,
1291 struct io_mapped_ubuf *imu,
1292 u64 buf_addr, size_t len)
1293{
1294 u64 buf_end;
1295 size_t offset;
1296
1297 if (WARN_ON_ONCE(!imu))
1298 return -EFAULT;
1299 if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
1300 return -EFAULT;
1301 /* not inside the mapped region */
1302 if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end))
1303 return -EFAULT;
1304
1305 /*
6bf65a1b 1306 * Might not be a start of buffer, set size appropriately
c059f785
PB		 1307 * and advance us to the beginning.
1308 */
1309 offset = buf_addr - imu->ubuf;
1310 iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len);
1311
1312 if (offset) {
1313 /*
1314 * Don't use iov_iter_advance() here, as it's really slow for
1315 * using the latter parts of a big fixed buffer - it iterates
1316 * over each segment manually. We can cheat a bit here, because
1317 * we know that:
1318 *
1319 * 1) it's a BVEC iter, we set it up
1320 * 2) all bvecs are PAGE_SIZE in size, except potentially the
1321 * first and last bvec
1322 *
1323 * So just find our index, and adjust the iterator afterwards.
1324 * If the offset is within the first bvec (or the whole first
1325 * bvec, just use iov_iter_advance(). This makes it easier
1326 * since we can just skip the first segment, which may not
1327 * be PAGE_SIZE aligned.
1328 */
1329 const struct bio_vec *bvec = imu->bvec;
1330
1331 if (offset <= bvec->bv_len) {
57bebf80
PB		 1332 /*
1333 * Note, huge pages buffers consists of one large
1334 * bvec entry and should always go this way. The other
1335 * branch doesn't expect non PAGE_SIZE'd chunks.
1336 */
b000ae0e
PB		 1337 iter->bvec = bvec;
1338 iter->nr_segs = bvec->bv_len;
1339 iter->count -= offset;
1340 iter->iov_offset = offset;
c059f785
PB		 1341 } else {
1342 unsigned long seg_skip;
1343
1344 /* skip first vec */
1345 offset -= bvec->bv_len;
1346 seg_skip = 1 + (offset >> PAGE_SHIFT);
1347
1348 iter->bvec = bvec + seg_skip;
1349 iter->nr_segs -= seg_skip;
1350 iter->count -= bvec->bv_len + offset;
1351 iter->iov_offset = offset & ~PAGE_MASK;
1352 }
1353 }
1354
1355 return 0;
1356}
Linux 6.x block layer and io_uring tree(s)