ublk: fix AB-BA lockdep warning
[linux-block.git] / drivers / block / ublk_drv.c
CommitLineData
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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Userspace block device - block device which IO is handled from userspace
4 *
5 * Take full use of io_uring passthrough command for communicating with
6 * ublk userspace daemon(ublksrvd) for handling basic IO request.
7 *
8 * Copyright 2022 Ming Lei <ming.lei@redhat.com>
9 *
10 * (part of code stolen from loop.c)
11 */
12#include <linux/module.h>
13#include <linux/moduleparam.h>
14#include <linux/sched.h>
15#include <linux/fs.h>
16#include <linux/pagemap.h>
17#include <linux/file.h>
18#include <linux/stat.h>
19#include <linux/errno.h>
20#include <linux/major.h>
21#include <linux/wait.h>
22#include <linux/blkdev.h>
23#include <linux/init.h>
24#include <linux/swap.h>
25#include <linux/slab.h>
26#include <linux/compat.h>
27#include <linux/mutex.h>
28#include <linux/writeback.h>
29#include <linux/completion.h>
30#include <linux/highmem.h>
31#include <linux/sysfs.h>
32#include <linux/miscdevice.h>
33#include <linux/falloc.h>
34#include <linux/uio.h>
35#include <linux/ioprio.h>
36#include <linux/sched/mm.h>
37#include <linux/uaccess.h>
38#include <linux/cdev.h>
39#include <linux/io_uring.h>
40#include <linux/blk-mq.h>
41#include <linux/delay.h>
42#include <linux/mm.h>
43#include <asm/page.h>
0edb3696 44#include <linux/task_work.h>
4093cb5a 45#include <linux/namei.h>
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46#include <uapi/linux/ublk_cmd.h>
47
48#define UBLK_MINORS (1U << MINORBITS)
49
6d8c5afc 50/* All UBLK_F_* have to be included into UBLK_F_ALL */
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51#define UBLK_F_ALL (UBLK_F_SUPPORT_ZERO_COPY \
52 | UBLK_F_URING_CMD_COMP_IN_TASK \
77a440e2 53 | UBLK_F_NEED_GET_DATA \
a0d41dc1 54 | UBLK_F_USER_RECOVERY \
4093cb5a 55 | UBLK_F_USER_RECOVERY_REISSUE \
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56 | UBLK_F_UNPRIVILEGED_DEV \
57 | UBLK_F_CMD_IOCTL_ENCODE)
6d8c5afc 58
0aa73170 59/* All UBLK_PARAM_TYPE_* should be included here */
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60#define UBLK_PARAM_TYPE_ALL (UBLK_PARAM_TYPE_BASIC | \
61 UBLK_PARAM_TYPE_DISCARD | UBLK_PARAM_TYPE_DEVT)
0aa73170 62
0edb3696 63struct ublk_rq_data {
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64 struct llist_node node;
65 struct callback_head work;
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66};
67
71f28f31 68struct ublk_uring_cmd_pdu {
3ab6e94c 69 struct ublk_queue *ubq;
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70};
71
72/*
73 * io command is active: sqe cmd is received, and its cqe isn't done
74 *
75 * If the flag is set, the io command is owned by ublk driver, and waited
76 * for incoming blk-mq request from the ublk block device.
77 *
78 * If the flag is cleared, the io command will be completed, and owned by
79 * ublk server.
80 */
81#define UBLK_IO_FLAG_ACTIVE 0x01
82
83/*
84 * IO command is completed via cqe, and it is being handled by ublksrv, and
85 * not committed yet
86 *
87 * Basically exclusively with UBLK_IO_FLAG_ACTIVE, so can be served for
88 * cross verification
89 */
90#define UBLK_IO_FLAG_OWNED_BY_SRV 0x02
91
92/*
93 * IO command is aborted, so this flag is set in case of
94 * !UBLK_IO_FLAG_ACTIVE.
95 *
96 * After this flag is observed, any pending or new incoming request
97 * associated with this io command will be failed immediately
98 */
99#define UBLK_IO_FLAG_ABORTED 0x04
100
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101/*
102 * UBLK_IO_FLAG_NEED_GET_DATA is set because IO command requires
103 * get data buffer address from ublksrv.
104 *
105 * Then, bio data could be copied into this data buffer for a WRITE request
106 * after the IO command is issued again and UBLK_IO_FLAG_NEED_GET_DATA is unset.
107 */
108#define UBLK_IO_FLAG_NEED_GET_DATA 0x08
109
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110struct ublk_io {
111 /* userspace buffer address from io cmd */
112 __u64 addr;
113 unsigned int flags;
114 int res;
115
116 struct io_uring_cmd *cmd;
117};
118
119struct ublk_queue {
120 int q_id;
121 int q_depth;
122
0edb3696 123 unsigned long flags;
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124 struct task_struct *ubq_daemon;
125 char *io_cmd_buf;
126
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127 struct llist_head io_cmds;
128
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129 unsigned long io_addr; /* mapped vm address */
130 unsigned int max_io_sz;
bbae8d1f 131 bool force_abort;
c0b79b0f 132 bool timeout;
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133 unsigned short nr_io_ready; /* how many ios setup */
134 struct ublk_device *dev;
72495b5a 135 struct ublk_io ios[];
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136};
137
138#define UBLK_DAEMON_MONITOR_PERIOD (5 * HZ)
139
140struct ublk_device {
141 struct gendisk *ub_disk;
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142
143 char *__queues;
144
29baef78 145 unsigned int queue_size;
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146 struct ublksrv_ctrl_dev_info dev_info;
147
148 struct blk_mq_tag_set tag_set;
149
150 struct cdev cdev;
151 struct device cdev_dev;
152
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153#define UB_STATE_OPEN 0
154#define UB_STATE_USED 1
0abe39de 155#define UB_STATE_DELETED 2
fa362045 156 unsigned long state;
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157 int ub_number;
158
159 struct mutex mutex;
160
e94eb459 161 spinlock_t mm_lock;
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162 struct mm_struct *mm;
163
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164 struct ublk_params params;
165
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166 struct completion completion;
167 unsigned int nr_queues_ready;
73a166d9 168 unsigned int nr_privileged_daemon;
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169
170 /*
171 * Our ubq->daemon may be killed without any notification, so
172 * monitor each queue's daemon periodically
173 */
174 struct delayed_work monitor_work;
bbae8d1f 175 struct work_struct quiesce_work;
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176 struct work_struct stop_work;
177};
178
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179/* header of ublk_params */
180struct ublk_params_header {
181 __u32 len;
182 __u32 types;
183};
184
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185static dev_t ublk_chr_devt;
186static struct class *ublk_chr_class;
187
188static DEFINE_IDR(ublk_index_idr);
189static DEFINE_SPINLOCK(ublk_idr_lock);
190static wait_queue_head_t ublk_idr_wq; /* wait until one idr is freed */
191
192static DEFINE_MUTEX(ublk_ctl_mutex);
193
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194/*
195 * Max ublk devices allowed to add
196 *
197 * It can be extended to one per-user limit in future or even controlled
198 * by cgroup.
199 */
200static unsigned int ublks_max = 64;
201static unsigned int ublks_added; /* protected by ublk_ctl_mutex */
202
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203static struct miscdevice ublk_misc;
204
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205static void ublk_dev_param_basic_apply(struct ublk_device *ub)
206{
207 struct request_queue *q = ub->ub_disk->queue;
208 const struct ublk_param_basic *p = &ub->params.basic;
209
210 blk_queue_logical_block_size(q, 1 << p->logical_bs_shift);
211 blk_queue_physical_block_size(q, 1 << p->physical_bs_shift);
212 blk_queue_io_min(q, 1 << p->io_min_shift);
213 blk_queue_io_opt(q, 1 << p->io_opt_shift);
214
215 blk_queue_write_cache(q, p->attrs & UBLK_ATTR_VOLATILE_CACHE,
216 p->attrs & UBLK_ATTR_FUA);
217 if (p->attrs & UBLK_ATTR_ROTATIONAL)
218 blk_queue_flag_clear(QUEUE_FLAG_NONROT, q);
219 else
220 blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
221
222 blk_queue_max_hw_sectors(q, p->max_sectors);
223 blk_queue_chunk_sectors(q, p->chunk_sectors);
224 blk_queue_virt_boundary(q, p->virt_boundary_mask);
225
226 if (p->attrs & UBLK_ATTR_READ_ONLY)
227 set_disk_ro(ub->ub_disk, true);
228
229 set_capacity(ub->ub_disk, p->dev_sectors);
230}
231
232static void ublk_dev_param_discard_apply(struct ublk_device *ub)
233{
234 struct request_queue *q = ub->ub_disk->queue;
235 const struct ublk_param_discard *p = &ub->params.discard;
236
237 q->limits.discard_alignment = p->discard_alignment;
238 q->limits.discard_granularity = p->discard_granularity;
239 blk_queue_max_discard_sectors(q, p->max_discard_sectors);
240 blk_queue_max_write_zeroes_sectors(q,
241 p->max_write_zeroes_sectors);
242 blk_queue_max_discard_segments(q, p->max_discard_segments);
243}
244
245static int ublk_validate_params(const struct ublk_device *ub)
246{
247 /* basic param is the only one which must be set */
248 if (ub->params.types & UBLK_PARAM_TYPE_BASIC) {
249 const struct ublk_param_basic *p = &ub->params.basic;
250
1d166527 251 if (p->logical_bs_shift > PAGE_SHIFT || p->logical_bs_shift < 9)
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252 return -EINVAL;
253
254 if (p->logical_bs_shift > p->physical_bs_shift)
255 return -EINVAL;
256
4bf9cbf3 257 if (p->max_sectors > (ub->dev_info.max_io_buf_bytes >> 9))
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258 return -EINVAL;
259 } else
260 return -EINVAL;
261
262 if (ub->params.types & UBLK_PARAM_TYPE_DISCARD) {
263 const struct ublk_param_discard *p = &ub->params.discard;
264
265 /* So far, only support single segment discard */
266 if (p->max_discard_sectors && p->max_discard_segments != 1)
267 return -EINVAL;
268
269 if (!p->discard_granularity)
270 return -EINVAL;
271 }
272
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273 /* dev_t is read-only */
274 if (ub->params.types & UBLK_PARAM_TYPE_DEVT)
275 return -EINVAL;
276
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277 return 0;
278}
279
280static int ublk_apply_params(struct ublk_device *ub)
281{
282 if (!(ub->params.types & UBLK_PARAM_TYPE_BASIC))
283 return -EINVAL;
284
285 ublk_dev_param_basic_apply(ub);
286
287 if (ub->params.types & UBLK_PARAM_TYPE_DISCARD)
288 ublk_dev_param_discard_apply(ub);
289
290 return 0;
291}
292
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293static inline bool ublk_can_use_task_work(const struct ublk_queue *ubq)
294{
295 if (IS_BUILTIN(CONFIG_BLK_DEV_UBLK) &&
296 !(ubq->flags & UBLK_F_URING_CMD_COMP_IN_TASK))
297 return true;
298 return false;
299}
300
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301static inline bool ublk_need_get_data(const struct ublk_queue *ubq)
302{
96cf2f54 303 return ubq->flags & UBLK_F_NEED_GET_DATA;
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304}
305
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306static struct ublk_device *ublk_get_device(struct ublk_device *ub)
307{
308 if (kobject_get_unless_zero(&ub->cdev_dev.kobj))
309 return ub;
310 return NULL;
311}
312
313static void ublk_put_device(struct ublk_device *ub)
314{
315 put_device(&ub->cdev_dev);
316}
317
318static inline struct ublk_queue *ublk_get_queue(struct ublk_device *dev,
319 int qid)
320{
321 return (struct ublk_queue *)&(dev->__queues[qid * dev->queue_size]);
322}
323
324static inline bool ublk_rq_has_data(const struct request *rq)
325{
731e208d 326 return bio_has_data(rq->bio);
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327}
328
329static inline struct ublksrv_io_desc *ublk_get_iod(struct ublk_queue *ubq,
330 int tag)
331{
332 return (struct ublksrv_io_desc *)
333 &(ubq->io_cmd_buf[tag * sizeof(struct ublksrv_io_desc)]);
334}
335
336static inline char *ublk_queue_cmd_buf(struct ublk_device *ub, int q_id)
337{
338 return ublk_get_queue(ub, q_id)->io_cmd_buf;
339}
340
341static inline int ublk_queue_cmd_buf_size(struct ublk_device *ub, int q_id)
342{
343 struct ublk_queue *ubq = ublk_get_queue(ub, q_id);
344
345 return round_up(ubq->q_depth * sizeof(struct ublksrv_io_desc),
346 PAGE_SIZE);
347}
348
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349static inline bool ublk_queue_can_use_recovery_reissue(
350 struct ublk_queue *ubq)
351{
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352 return (ubq->flags & UBLK_F_USER_RECOVERY) &&
353 (ubq->flags & UBLK_F_USER_RECOVERY_REISSUE);
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354}
355
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356static inline bool ublk_queue_can_use_recovery(
357 struct ublk_queue *ubq)
358{
96cf2f54 359 return ubq->flags & UBLK_F_USER_RECOVERY;
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360}
361
362static inline bool ublk_can_use_recovery(struct ublk_device *ub)
363{
96cf2f54 364 return ub->dev_info.flags & UBLK_F_USER_RECOVERY;
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365}
366
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367static void ublk_free_disk(struct gendisk *disk)
368{
369 struct ublk_device *ub = disk->private_data;
370
371 clear_bit(UB_STATE_USED, &ub->state);
372 put_device(&ub->cdev_dev);
373}
374
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375static void ublk_store_owner_uid_gid(unsigned int *owner_uid,
376 unsigned int *owner_gid)
377{
378 kuid_t uid;
379 kgid_t gid;
380
381 current_uid_gid(&uid, &gid);
382
383 *owner_uid = from_kuid(&init_user_ns, uid);
384 *owner_gid = from_kgid(&init_user_ns, gid);
385}
386
387static int ublk_open(struct block_device *bdev, fmode_t mode)
388{
389 struct ublk_device *ub = bdev->bd_disk->private_data;
390
391 if (capable(CAP_SYS_ADMIN))
392 return 0;
393
394 /*
395 * If it is one unprivileged device, only owner can open
396 * the disk. Otherwise it could be one trap made by one
397 * evil user who grants this disk's privileges to other
398 * users deliberately.
399 *
400 * This way is reasonable too given anyone can create
401 * unprivileged device, and no need other's grant.
402 */
403 if (ub->dev_info.flags & UBLK_F_UNPRIVILEGED_DEV) {
404 unsigned int curr_uid, curr_gid;
405
406 ublk_store_owner_uid_gid(&curr_uid, &curr_gid);
407
408 if (curr_uid != ub->dev_info.owner_uid || curr_gid !=
409 ub->dev_info.owner_gid)
410 return -EPERM;
411 }
412
413 return 0;
414}
415
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416static const struct block_device_operations ub_fops = {
417 .owner = THIS_MODULE,
48a90519 418 .open = ublk_open,
6d9e6dfd 419 .free_disk = ublk_free_disk,
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420};
421
422#define UBLK_MAX_PIN_PAGES 32
423
424struct ublk_map_data {
71f28f31 425 const struct request *rq;
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426 unsigned long ubuf;
427 unsigned int len;
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428};
429
430struct ublk_io_iter {
431 struct page *pages[UBLK_MAX_PIN_PAGES];
432 unsigned pg_off; /* offset in the 1st page in pages */
433 int nr_pages; /* how many page pointers in pages */
434 struct bio *bio;
435 struct bvec_iter iter;
436};
437
438static inline unsigned ublk_copy_io_pages(struct ublk_io_iter *data,
439 unsigned max_bytes, bool to_vm)
440{
441 const unsigned total = min_t(unsigned, max_bytes,
442 PAGE_SIZE - data->pg_off +
443 ((data->nr_pages - 1) << PAGE_SHIFT));
444 unsigned done = 0;
445 unsigned pg_idx = 0;
446
447 while (done < total) {
448 struct bio_vec bv = bio_iter_iovec(data->bio, data->iter);
449 const unsigned int bytes = min3(bv.bv_len, total - done,
450 (unsigned)(PAGE_SIZE - data->pg_off));
451 void *bv_buf = bvec_kmap_local(&bv);
452 void *pg_buf = kmap_local_page(data->pages[pg_idx]);
453
454 if (to_vm)
455 memcpy(pg_buf + data->pg_off, bv_buf, bytes);
456 else
457 memcpy(bv_buf, pg_buf + data->pg_off, bytes);
458
459 kunmap_local(pg_buf);
460 kunmap_local(bv_buf);
461
462 /* advance page array */
463 data->pg_off += bytes;
464 if (data->pg_off == PAGE_SIZE) {
465 pg_idx += 1;
466 data->pg_off = 0;
467 }
468
469 done += bytes;
470
471 /* advance bio */
472 bio_advance_iter_single(data->bio, &data->iter, bytes);
473 if (!data->iter.bi_size) {
474 data->bio = data->bio->bi_next;
475 if (data->bio == NULL)
476 break;
477 data->iter = data->bio->bi_iter;
478 }
479 }
480
481 return done;
482}
483
2f3af723 484static int ublk_copy_user_pages(struct ublk_map_data *data, bool to_vm)
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485{
486 const unsigned int gup_flags = to_vm ? FOLL_WRITE : 0;
ae9f5cce 487 const unsigned long start_vm = data->ubuf;
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488 unsigned int done = 0;
489 struct ublk_io_iter iter = {
490 .pg_off = start_vm & (PAGE_SIZE - 1),
491 .bio = data->rq->bio,
492 .iter = data->rq->bio->bi_iter,
493 };
ae9f5cce 494 const unsigned int nr_pages = round_up(data->len +
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495 (start_vm & (PAGE_SIZE - 1)), PAGE_SIZE) >> PAGE_SHIFT;
496
497 while (done < nr_pages) {
498 const unsigned to_pin = min_t(unsigned, UBLK_MAX_PIN_PAGES,
499 nr_pages - done);
500 unsigned i, len;
501
502 iter.nr_pages = get_user_pages_fast(start_vm +
503 (done << PAGE_SHIFT), to_pin, gup_flags,
504 iter.pages);
505 if (iter.nr_pages <= 0)
506 return done == 0 ? iter.nr_pages : done;
ae9f5cce 507 len = ublk_copy_io_pages(&iter, data->len, to_vm);
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508 for (i = 0; i < iter.nr_pages; i++) {
509 if (to_vm)
510 set_page_dirty(iter.pages[i]);
511 put_page(iter.pages[i]);
512 }
ae9f5cce 513 data->len -= len;
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514 done += iter.nr_pages;
515 }
516
517 return done;
518}
519
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520static inline bool ublk_need_map_req(const struct request *req)
521{
522 return ublk_rq_has_data(req) && req_op(req) == REQ_OP_WRITE;
523}
524
525static inline bool ublk_need_unmap_req(const struct request *req)
526{
527 return ublk_rq_has_data(req) && req_op(req) == REQ_OP_READ;
528}
529
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530static int ublk_map_io(const struct ublk_queue *ubq, const struct request *req,
531 struct ublk_io *io)
532{
533 const unsigned int rq_bytes = blk_rq_bytes(req);
23ef8220 534
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535 /*
536 * no zero copy, we delay copy WRITE request data into ublksrv
537 * context and the big benefit is that pinning pages in current
538 * context is pretty fast, see ublk_pin_user_pages
539 */
2f3af723 540 if (ublk_need_map_req(req)) {
71f28f31 541 struct ublk_map_data data = {
71f28f31 542 .rq = req,
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543 .ubuf = io->addr,
544 .len = rq_bytes,
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545 };
546
547 ublk_copy_user_pages(&data, true);
548
ae9f5cce 549 return rq_bytes - data.len;
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550 }
551 return rq_bytes;
552}
553
554static int ublk_unmap_io(const struct ublk_queue *ubq,
555 const struct request *req,
556 struct ublk_io *io)
557{
558 const unsigned int rq_bytes = blk_rq_bytes(req);
559
2f3af723 560 if (ublk_need_unmap_req(req)) {
71f28f31 561 struct ublk_map_data data = {
71f28f31 562 .rq = req,
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563 .ubuf = io->addr,
564 .len = io->res,
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565 };
566
567 WARN_ON_ONCE(io->res > rq_bytes);
568
569 ublk_copy_user_pages(&data, false);
570
ae9f5cce 571 return io->res - data.len;
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572 }
573 return rq_bytes;
574}
575
576static inline unsigned int ublk_req_build_flags(struct request *req)
577{
578 unsigned flags = 0;
579
580 if (req->cmd_flags & REQ_FAILFAST_DEV)
581 flags |= UBLK_IO_F_FAILFAST_DEV;
582
583 if (req->cmd_flags & REQ_FAILFAST_TRANSPORT)
584 flags |= UBLK_IO_F_FAILFAST_TRANSPORT;
585
586 if (req->cmd_flags & REQ_FAILFAST_DRIVER)
587 flags |= UBLK_IO_F_FAILFAST_DRIVER;
588
589 if (req->cmd_flags & REQ_META)
590 flags |= UBLK_IO_F_META;
591
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592 if (req->cmd_flags & REQ_FUA)
593 flags |= UBLK_IO_F_FUA;
594
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595 if (req->cmd_flags & REQ_NOUNMAP)
596 flags |= UBLK_IO_F_NOUNMAP;
597
598 if (req->cmd_flags & REQ_SWAP)
599 flags |= UBLK_IO_F_SWAP;
600
601 return flags;
602}
603
f2450f8a 604static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
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605{
606 struct ublksrv_io_desc *iod = ublk_get_iod(ubq, req->tag);
607 struct ublk_io *io = &ubq->ios[req->tag];
608 u32 ublk_op;
609
610 switch (req_op(req)) {
611 case REQ_OP_READ:
612 ublk_op = UBLK_IO_OP_READ;
613 break;
614 case REQ_OP_WRITE:
615 ublk_op = UBLK_IO_OP_WRITE;
616 break;
617 case REQ_OP_FLUSH:
618 ublk_op = UBLK_IO_OP_FLUSH;
619 break;
620 case REQ_OP_DISCARD:
621 ublk_op = UBLK_IO_OP_DISCARD;
622 break;
623 case REQ_OP_WRITE_ZEROES:
624 ublk_op = UBLK_IO_OP_WRITE_ZEROES;
625 break;
626 default:
627 return BLK_STS_IOERR;
628 }
629
630 /* need to translate since kernel may change */
631 iod->op_flags = ublk_op | ublk_req_build_flags(req);
632 iod->nr_sectors = blk_rq_sectors(req);
633 iod->start_sector = blk_rq_pos(req);
634 iod->addr = io->addr;
635
636 return BLK_STS_OK;
637}
638
639static inline struct ublk_uring_cmd_pdu *ublk_get_uring_cmd_pdu(
640 struct io_uring_cmd *ioucmd)
641{
642 return (struct ublk_uring_cmd_pdu *)&ioucmd->pdu;
643}
644
966120b5 645static inline bool ubq_daemon_is_dying(struct ublk_queue *ubq)
71f28f31
ML
646{
647 return ubq->ubq_daemon->flags & PF_EXITING;
648}
649
650/* todo: handle partial completion */
651static void ublk_complete_rq(struct request *req)
652{
653 struct ublk_queue *ubq = req->mq_hctx->driver_data;
654 struct ublk_io *io = &ubq->ios[req->tag];
655 unsigned int unmapped_bytes;
903f8aee 656 blk_status_t res = BLK_STS_OK;
71f28f31
ML
657
658 /* failed read IO if nothing is read */
659 if (!io->res && req_op(req) == REQ_OP_READ)
660 io->res = -EIO;
661
662 if (io->res < 0) {
903f8aee
ML
663 res = errno_to_blk_status(io->res);
664 goto exit;
71f28f31
ML
665 }
666
667 /*
b352389e 668 * FLUSH, DISCARD or WRITE_ZEROES usually won't return bytes returned, so end them
71f28f31
ML
669 * directly.
670 *
671 * Both the two needn't unmap.
672 */
903f8aee
ML
673 if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE)
674 goto exit;
71f28f31
ML
675
676 /* for READ request, writing data in iod->addr to rq buffers */
677 unmapped_bytes = ublk_unmap_io(ubq, req, io);
678
679 /*
680 * Extremely impossible since we got data filled in just before
681 *
682 * Re-read simply for this unlikely case.
683 */
684 if (unlikely(unmapped_bytes < io->res))
685 io->res = unmapped_bytes;
686
687 if (blk_update_request(req, BLK_STS_OK, io->res))
688 blk_mq_requeue_request(req, true);
689 else
690 __blk_mq_end_request(req, BLK_STS_OK);
903f8aee
ML
691
692 return;
693exit:
694 blk_mq_end_request(req, res);
71f28f31
ML
695}
696
697/*
bb241747
Z
698 * Since __ublk_rq_task_work always fails requests immediately during
699 * exiting, __ublk_fail_req() is only called from abort context during
700 * exiting. So lock is unnecessary.
71f28f31
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701 *
702 * Also aborting may not be started yet, keep in mind that one failed
703 * request may be issued by block layer again.
704 */
a0d41dc1
Z
705static void __ublk_fail_req(struct ublk_queue *ubq, struct ublk_io *io,
706 struct request *req)
71f28f31
ML
707{
708 WARN_ON_ONCE(io->flags & UBLK_IO_FLAG_ACTIVE);
709
710 if (!(io->flags & UBLK_IO_FLAG_ABORTED)) {
711 io->flags |= UBLK_IO_FLAG_ABORTED;
a0d41dc1
Z
712 if (ublk_queue_can_use_recovery_reissue(ubq))
713 blk_mq_requeue_request(req, false);
714 else
715 blk_mq_end_request(req, BLK_STS_IOERR);
71f28f31
ML
716 }
717}
718
9d2789ac
JA
719static void ubq_complete_io_cmd(struct ublk_io *io, int res,
720 unsigned issue_flags)
c86019ff
Z
721{
722 /* mark this cmd owned by ublksrv */
723 io->flags |= UBLK_IO_FLAG_OWNED_BY_SRV;
724
725 /*
726 * clear ACTIVE since we are done with this sqe/cmd slot
727 * We can only accept io cmd in case of being not active.
728 */
729 io->flags &= ~UBLK_IO_FLAG_ACTIVE;
730
731 /* tell ublksrv one io request is coming */
9d2789ac 732 io_uring_cmd_done(io->cmd, res, 0, issue_flags);
c86019ff
Z
733}
734
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735#define UBLK_REQUEUE_DELAY_MS 3
736
42cf5fc5
Z
737static inline void __ublk_abort_rq(struct ublk_queue *ubq,
738 struct request *rq)
739{
740 /* We cannot process this rq so just requeue it. */
741 if (ublk_queue_can_use_recovery(ubq))
742 blk_mq_requeue_request(rq, false);
743 else
744 blk_mq_end_request(rq, BLK_STS_IOERR);
745
746 mod_delayed_work(system_wq, &ubq->dev->monitor_work, 0);
747}
748
9d2789ac
JA
749static inline void __ublk_rq_task_work(struct request *req,
750 unsigned issue_flags)
71f28f31 751{
71f28f31
ML
752 struct ublk_queue *ubq = req->mq_hctx->driver_data;
753 int tag = req->tag;
754 struct ublk_io *io = &ubq->ios[tag];
71f28f31
ML
755 unsigned int mapped_bytes;
756
757 pr_devel("%s: complete: op %d, qid %d tag %d io_flags %x addr %llx\n",
758 __func__, io->cmd->cmd_op, ubq->q_id, req->tag, io->flags,
759 ublk_get_iod(ubq, req->tag)->addr);
760
ae3f7193
Z
761 /*
762 * Task is exiting if either:
763 *
764 * (1) current != ubq_daemon.
765 * io_uring_cmd_complete_in_task() tries to run task_work
766 * in a workqueue if ubq_daemon(cmd's task) is PF_EXITING.
767 *
768 * (2) current->flags & PF_EXITING.
769 */
770 if (unlikely(current != ubq->ubq_daemon || current->flags & PF_EXITING)) {
42cf5fc5 771 __ublk_abort_rq(ubq, req);
71f28f31
ML
772 return;
773 }
774
2f3af723 775 if (ublk_need_get_data(ubq) && ublk_need_map_req(req)) {
c86019ff
Z
776 /*
777 * We have not handled UBLK_IO_NEED_GET_DATA command yet,
778 * so immepdately pass UBLK_IO_RES_NEED_GET_DATA to ublksrv
779 * and notify it.
780 */
781 if (!(io->flags & UBLK_IO_FLAG_NEED_GET_DATA)) {
782 io->flags |= UBLK_IO_FLAG_NEED_GET_DATA;
783 pr_devel("%s: need get data. op %d, qid %d tag %d io_flags %x\n",
784 __func__, io->cmd->cmd_op, ubq->q_id,
785 req->tag, io->flags);
9d2789ac 786 ubq_complete_io_cmd(io, UBLK_IO_RES_NEED_GET_DATA, issue_flags);
c86019ff
Z
787 return;
788 }
789 /*
790 * We have handled UBLK_IO_NEED_GET_DATA command,
791 * so clear UBLK_IO_FLAG_NEED_GET_DATA now and just
792 * do the copy work.
793 */
794 io->flags &= ~UBLK_IO_FLAG_NEED_GET_DATA;
92cb6e2e
Z
795 /* update iod->addr because ublksrv may have passed a new io buffer */
796 ublk_get_iod(ubq, req->tag)->addr = io->addr;
797 pr_devel("%s: update iod->addr: op %d, qid %d tag %d io_flags %x addr %llx\n",
798 __func__, io->cmd->cmd_op, ubq->q_id, req->tag, io->flags,
799 ublk_get_iod(ubq, req->tag)->addr);
c86019ff
Z
800 }
801
71f28f31
ML
802 mapped_bytes = ublk_map_io(ubq, req, io);
803
804 /* partially mapped, update io descriptor */
805 if (unlikely(mapped_bytes != blk_rq_bytes(req))) {
806 /*
807 * Nothing mapped, retry until we succeed.
808 *
809 * We may never succeed in mapping any bytes here because
810 * of OOM. TODO: reserve one buffer with single page pinned
811 * for providing forward progress guarantee.
812 */
813 if (unlikely(!mapped_bytes)) {
814 blk_mq_requeue_request(req, false);
815 blk_mq_delay_kick_requeue_list(req->q,
816 UBLK_REQUEUE_DELAY_MS);
817 return;
818 }
819
820 ublk_get_iod(ubq, req->tag)->nr_sectors =
821 mapped_bytes >> 9;
822 }
823
9d2789ac 824 ubq_complete_io_cmd(io, UBLK_IO_RES_OK, issue_flags);
71f28f31
ML
825}
826
9d2789ac
JA
827static inline void ublk_forward_io_cmds(struct ublk_queue *ubq,
828 unsigned issue_flags)
7d4a9317
ML
829{
830 struct llist_node *io_cmds = llist_del_all(&ubq->io_cmds);
831 struct ublk_rq_data *data, *tmp;
832
833 io_cmds = llist_reverse_order(io_cmds);
834 llist_for_each_entry_safe(data, tmp, io_cmds, node)
9d2789ac 835 __ublk_rq_task_work(blk_mq_rq_from_pdu(data), issue_flags);
7d4a9317
ML
836}
837
838static inline void ublk_abort_io_cmds(struct ublk_queue *ubq)
839{
840 struct llist_node *io_cmds = llist_del_all(&ubq->io_cmds);
841 struct ublk_rq_data *data, *tmp;
842
843 llist_for_each_entry_safe(data, tmp, io_cmds, node)
844 __ublk_abort_rq(ubq, blk_mq_rq_from_pdu(data));
845}
846
9d2789ac 847static void ublk_rq_task_work_cb(struct io_uring_cmd *cmd, unsigned issue_flags)
0edb3696
ML
848{
849 struct ublk_uring_cmd_pdu *pdu = ublk_get_uring_cmd_pdu(cmd);
3ab6e94c 850 struct ublk_queue *ubq = pdu->ubq;
0edb3696 851
9d2789ac 852 ublk_forward_io_cmds(ubq, issue_flags);
0edb3696
ML
853}
854
855static void ublk_rq_task_work_fn(struct callback_head *work)
856{
857 struct ublk_rq_data *data = container_of(work,
858 struct ublk_rq_data, work);
859 struct request *req = blk_mq_rq_from_pdu(data);
7d4a9317 860 struct ublk_queue *ubq = req->mq_hctx->driver_data;
9d2789ac 861 unsigned issue_flags = IO_URING_F_UNLOCKED;
0edb3696 862
9d2789ac 863 ublk_forward_io_cmds(ubq, issue_flags);
0edb3696
ML
864}
865
7d4a9317 866static void ublk_queue_cmd(struct ublk_queue *ubq, struct request *rq)
3ab6e94c 867{
7d4a9317
ML
868 struct ublk_rq_data *data = blk_mq_rq_to_pdu(rq);
869 struct ublk_io *io;
3ab6e94c 870
7d4a9317
ML
871 if (!llist_add(&data->node, &ubq->io_cmds))
872 return;
873
874 io = &ubq->ios[rq->tag];
3ab6e94c
ML
875 /*
876 * If the check pass, we know that this is a re-issued request aborted
877 * previously in monitor_work because the ubq_daemon(cmd's task) is
878 * PF_EXITING. We cannot call io_uring_cmd_complete_in_task() anymore
879 * because this ioucmd's io_uring context may be freed now if no inflight
880 * ioucmd exists. Otherwise we may cause null-deref in ctx->fallback_work.
881 *
882 * Note: monitor_work sets UBLK_IO_FLAG_ABORTED and ends this request(releasing
883 * the tag). Then the request is re-started(allocating the tag) and we are here.
884 * Since releasing/allocating a tag implies smp_mb(), finding UBLK_IO_FLAG_ABORTED
885 * guarantees that here is a re-issued request aborted previously.
886 */
887 if (unlikely(io->flags & UBLK_IO_FLAG_ABORTED)) {
7d4a9317
ML
888 ublk_abort_io_cmds(ubq);
889 } else if (ublk_can_use_task_work(ubq)) {
890 if (task_work_add(ubq->ubq_daemon, &data->work,
891 TWA_SIGNAL_NO_IPI))
892 ublk_abort_io_cmds(ubq);
3ab6e94c
ML
893 } else {
894 struct io_uring_cmd *cmd = io->cmd;
895 struct ublk_uring_cmd_pdu *pdu = ublk_get_uring_cmd_pdu(cmd);
896
897 pdu->ubq = ubq;
898 io_uring_cmd_complete_in_task(cmd, ublk_rq_task_work_cb);
899 }
900}
901
c0b79b0f
ML
902static enum blk_eh_timer_return ublk_timeout(struct request *rq)
903{
904 struct ublk_queue *ubq = rq->mq_hctx->driver_data;
905
906 if (ubq->flags & UBLK_F_UNPRIVILEGED_DEV) {
907 if (!ubq->timeout) {
908 send_sig(SIGKILL, ubq->ubq_daemon, 0);
909 ubq->timeout = true;
910 }
911
912 return BLK_EH_DONE;
913 }
914
915 return BLK_EH_RESET_TIMER;
916}
917
71f28f31
ML
918static blk_status_t ublk_queue_rq(struct blk_mq_hw_ctx *hctx,
919 const struct blk_mq_queue_data *bd)
920{
921 struct ublk_queue *ubq = hctx->driver_data;
922 struct request *rq = bd->rq;
71f28f31
ML
923 blk_status_t res;
924
925 /* fill iod to slot in io cmd buffer */
926 res = ublk_setup_iod(ubq, rq);
927 if (unlikely(res != BLK_STS_OK))
928 return BLK_STS_IOERR;
3ab6e94c 929
bbae8d1f
Z
930 /* With recovery feature enabled, force_abort is set in
931 * ublk_stop_dev() before calling del_gendisk(). We have to
932 * abort all requeued and new rqs here to let del_gendisk()
933 * move on. Besides, we cannot not call io_uring_cmd_complete_in_task()
934 * to avoid UAF on io_uring ctx.
935 *
936 * Note: force_abort is guaranteed to be seen because it is set
937 * before request queue is unqiuesced.
938 */
939 if (ublk_queue_can_use_recovery(ubq) && unlikely(ubq->force_abort))
940 return BLK_STS_IOERR;
71f28f31
ML
941
942 blk_mq_start_request(bd->rq);
943
944 if (unlikely(ubq_daemon_is_dying(ubq))) {
42cf5fc5
Z
945 __ublk_abort_rq(ubq, rq);
946 return BLK_STS_OK;
71f28f31
ML
947 }
948
7d4a9317 949 ublk_queue_cmd(ubq, rq);
0edb3696 950
71f28f31
ML
951 return BLK_STS_OK;
952}
953
71f28f31
ML
954static int ublk_init_hctx(struct blk_mq_hw_ctx *hctx, void *driver_data,
955 unsigned int hctx_idx)
956{
cebbe577 957 struct ublk_device *ub = driver_data;
71f28f31
ML
958 struct ublk_queue *ubq = ublk_get_queue(ub, hctx->queue_num);
959
960 hctx->driver_data = ubq;
961 return 0;
962}
963
0edb3696
ML
964static int ublk_init_rq(struct blk_mq_tag_set *set, struct request *req,
965 unsigned int hctx_idx, unsigned int numa_node)
966{
967 struct ublk_rq_data *data = blk_mq_rq_to_pdu(req);
968
969 init_task_work(&data->work, ublk_rq_task_work_fn);
970 return 0;
971}
972
71f28f31
ML
973static const struct blk_mq_ops ublk_mq_ops = {
974 .queue_rq = ublk_queue_rq,
975 .init_hctx = ublk_init_hctx,
0edb3696 976 .init_request = ublk_init_rq,
c0b79b0f 977 .timeout = ublk_timeout,
71f28f31
ML
978};
979
980static int ublk_ch_open(struct inode *inode, struct file *filp)
981{
982 struct ublk_device *ub = container_of(inode->i_cdev,
983 struct ublk_device, cdev);
984
fa362045
CH
985 if (test_and_set_bit(UB_STATE_OPEN, &ub->state))
986 return -EBUSY;
987 filp->private_data = ub;
988 return 0;
71f28f31
ML
989}
990
991static int ublk_ch_release(struct inode *inode, struct file *filp)
992{
993 struct ublk_device *ub = filp->private_data;
994
fa362045 995 clear_bit(UB_STATE_OPEN, &ub->state);
71f28f31
ML
996 return 0;
997}
998
999/* map pre-allocated per-queue cmd buffer to ublksrv daemon */
1000static int ublk_ch_mmap(struct file *filp, struct vm_area_struct *vma)
1001{
1002 struct ublk_device *ub = filp->private_data;
1003 size_t sz = vma->vm_end - vma->vm_start;
1004 unsigned max_sz = UBLK_MAX_QUEUE_DEPTH * sizeof(struct ublksrv_io_desc);
1005 unsigned long pfn, end, phys_off = vma->vm_pgoff << PAGE_SHIFT;
1006 int q_id, ret = 0;
1007
e94eb459 1008 spin_lock(&ub->mm_lock);
71f28f31
ML
1009 if (!ub->mm)
1010 ub->mm = current->mm;
1011 if (current->mm != ub->mm)
1012 ret = -EINVAL;
e94eb459 1013 spin_unlock(&ub->mm_lock);
71f28f31
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1014
1015 if (ret)
1016 return ret;
1017
1018 if (vma->vm_flags & VM_WRITE)
1019 return -EPERM;
1020
1021 end = UBLKSRV_CMD_BUF_OFFSET + ub->dev_info.nr_hw_queues * max_sz;
1022 if (phys_off < UBLKSRV_CMD_BUF_OFFSET || phys_off >= end)
1023 return -EINVAL;
1024
1025 q_id = (phys_off - UBLKSRV_CMD_BUF_OFFSET) / max_sz;
1026 pr_devel("%s: qid %d, pid %d, addr %lx pg_off %lx sz %lu\n",
1027 __func__, q_id, current->pid, vma->vm_start,
1028 phys_off, (unsigned long)sz);
1029
1030 if (sz != ublk_queue_cmd_buf_size(ub, q_id))
1031 return -EINVAL;
1032
1033 pfn = virt_to_phys(ublk_queue_cmd_buf(ub, q_id)) >> PAGE_SHIFT;
1034 return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot);
1035}
1036
1037static void ublk_commit_completion(struct ublk_device *ub,
fd9b8547 1038 const struct ublksrv_io_cmd *ub_cmd)
71f28f31
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1039{
1040 u32 qid = ub_cmd->q_id, tag = ub_cmd->tag;
1041 struct ublk_queue *ubq = ublk_get_queue(ub, qid);
1042 struct ublk_io *io = &ubq->ios[tag];
1043 struct request *req;
1044
1045 /* now this cmd slot is owned by nbd driver */
1046 io->flags &= ~UBLK_IO_FLAG_OWNED_BY_SRV;
1047 io->res = ub_cmd->result;
1048
1049 /* find the io request and complete */
1050 req = blk_mq_tag_to_rq(ub->tag_set.tags[qid], tag);
1051
1052 if (req && likely(!blk_should_fake_timeout(req->q)))
1053 ublk_complete_rq(req);
1054}
1055
1056/*
1057 * When ->ubq_daemon is exiting, either new request is ended immediately,
1058 * or any queued io command is drained, so it is safe to abort queue
1059 * lockless
1060 */
1061static void ublk_abort_queue(struct ublk_device *ub, struct ublk_queue *ubq)
1062{
1063 int i;
1064
1065 if (!ublk_get_device(ub))
1066 return;
1067
1068 for (i = 0; i < ubq->q_depth; i++) {
1069 struct ublk_io *io = &ubq->ios[i];
1070
1071 if (!(io->flags & UBLK_IO_FLAG_ACTIVE)) {
1072 struct request *rq;
1073
1074 /*
1075 * Either we fail the request or ublk_rq_task_work_fn
1076 * will do it
1077 */
1078 rq = blk_mq_tag_to_rq(ub->tag_set.tags[ubq->q_id], i);
1079 if (rq)
a0d41dc1 1080 __ublk_fail_req(ubq, io, rq);
71f28f31
ML
1081 }
1082 }
1083 ublk_put_device(ub);
1084}
1085
1086static void ublk_daemon_monitor_work(struct work_struct *work)
1087{
1088 struct ublk_device *ub =
1089 container_of(work, struct ublk_device, monitor_work.work);
1090 int i;
1091
1092 for (i = 0; i < ub->dev_info.nr_hw_queues; i++) {
1093 struct ublk_queue *ubq = ublk_get_queue(ub, i);
1094
1095 if (ubq_daemon_is_dying(ubq)) {
bbae8d1f
Z
1096 if (ublk_queue_can_use_recovery(ubq))
1097 schedule_work(&ub->quiesce_work);
1098 else
1099 schedule_work(&ub->stop_work);
71f28f31
ML
1100
1101 /* abort queue is for making forward progress */
1102 ublk_abort_queue(ub, ubq);
1103 }
1104 }
1105
1106 /*
bbae8d1f
Z
1107 * We can't schedule monitor work after ub's state is not UBLK_S_DEV_LIVE.
1108 * after ublk_remove() or __ublk_quiesce_dev() is started.
71f28f31
ML
1109 *
1110 * No need ub->mutex, monitor work are canceled after state is marked
bbae8d1f 1111 * as not LIVE, so new state is observed reliably.
71f28f31 1112 */
bbae8d1f 1113 if (ub->dev_info.state == UBLK_S_DEV_LIVE)
71f28f31
ML
1114 schedule_delayed_work(&ub->monitor_work,
1115 UBLK_DAEMON_MONITOR_PERIOD);
1116}
1117
a8ce5f52
ML
1118static inline bool ublk_queue_ready(struct ublk_queue *ubq)
1119{
1120 return ubq->nr_io_ready == ubq->q_depth;
1121}
1122
ac5902f8
ML
1123static void ublk_cmd_cancel_cb(struct io_uring_cmd *cmd, unsigned issue_flags)
1124{
1125 io_uring_cmd_done(cmd, UBLK_IO_RES_ABORT, 0, issue_flags);
1126}
1127
71f28f31
ML
1128static void ublk_cancel_queue(struct ublk_queue *ubq)
1129{
1130 int i;
1131
a8ce5f52
ML
1132 if (!ublk_queue_ready(ubq))
1133 return;
1134
71f28f31
ML
1135 for (i = 0; i < ubq->q_depth; i++) {
1136 struct ublk_io *io = &ubq->ios[i];
1137
1138 if (io->flags & UBLK_IO_FLAG_ACTIVE)
ac5902f8
ML
1139 io_uring_cmd_complete_in_task(io->cmd,
1140 ublk_cmd_cancel_cb);
71f28f31 1141 }
a8ce5f52
ML
1142
1143 /* all io commands are canceled */
1144 ubq->nr_io_ready = 0;
71f28f31
ML
1145}
1146
1147/* Cancel all pending commands, must be called after del_gendisk() returns */
1148static void ublk_cancel_dev(struct ublk_device *ub)
1149{
1150 int i;
1151
1152 for (i = 0; i < ub->dev_info.nr_hw_queues; i++)
1153 ublk_cancel_queue(ublk_get_queue(ub, i));
1154}
1155
bbae8d1f
Z
1156static bool ublk_check_inflight_rq(struct request *rq, void *data)
1157{
1158 bool *idle = data;
1159
1160 if (blk_mq_request_started(rq)) {
1161 *idle = false;
1162 return false;
1163 }
1164 return true;
1165}
1166
1167static void ublk_wait_tagset_rqs_idle(struct ublk_device *ub)
1168{
1169 bool idle;
1170
1171 WARN_ON_ONCE(!blk_queue_quiesced(ub->ub_disk->queue));
1172 while (true) {
1173 idle = true;
1174 blk_mq_tagset_busy_iter(&ub->tag_set,
1175 ublk_check_inflight_rq, &idle);
1176 if (idle)
1177 break;
1178 msleep(UBLK_REQUEUE_DELAY_MS);
1179 }
1180}
1181
1182static void __ublk_quiesce_dev(struct ublk_device *ub)
71f28f31 1183{
bbae8d1f
Z
1184 pr_devel("%s: quiesce ub: dev_id %d state %s\n",
1185 __func__, ub->dev_info.dev_id,
1186 ub->dev_info.state == UBLK_S_DEV_LIVE ?
1187 "LIVE" : "QUIESCED");
1188 blk_mq_quiesce_queue(ub->ub_disk->queue);
1189 ublk_wait_tagset_rqs_idle(ub);
1190 ub->dev_info.state = UBLK_S_DEV_QUIESCED;
1191 ublk_cancel_dev(ub);
1192 /* we are going to release task_struct of ubq_daemon and resets
1193 * ->ubq_daemon to NULL. So in monitor_work, check on ubq_daemon causes UAF.
1194 * Besides, monitor_work is not necessary in QUIESCED state since we have
1195 * already scheduled quiesce_work and quiesced all ubqs.
1196 *
1197 * Do not let monitor_work schedule itself if state it QUIESCED. And we cancel
1198 * it here and re-schedule it in END_USER_RECOVERY to avoid UAF.
1199 */
1200 cancel_delayed_work_sync(&ub->monitor_work);
1201}
1202
1203static void ublk_quiesce_work_fn(struct work_struct *work)
1204{
1205 struct ublk_device *ub =
1206 container_of(work, struct ublk_device, quiesce_work);
1207
71f28f31 1208 mutex_lock(&ub->mutex);
6d9e6dfd 1209 if (ub->dev_info.state != UBLK_S_DEV_LIVE)
71f28f31 1210 goto unlock;
bbae8d1f
Z
1211 __ublk_quiesce_dev(ub);
1212 unlock:
1213 mutex_unlock(&ub->mutex);
1214}
71f28f31 1215
bbae8d1f
Z
1216static void ublk_unquiesce_dev(struct ublk_device *ub)
1217{
1218 int i;
1219
1220 pr_devel("%s: unquiesce ub: dev_id %d state %s\n",
1221 __func__, ub->dev_info.dev_id,
1222 ub->dev_info.state == UBLK_S_DEV_LIVE ?
1223 "LIVE" : "QUIESCED");
1224 /* quiesce_work has run. We let requeued rqs be aborted
1225 * before running fallback_wq. "force_abort" must be seen
1226 * after request queue is unqiuesced. Then del_gendisk()
1227 * can move on.
1228 */
1229 for (i = 0; i < ub->dev_info.nr_hw_queues; i++)
1230 ublk_get_queue(ub, i)->force_abort = true;
1231
1232 blk_mq_unquiesce_queue(ub->ub_disk->queue);
1233 /* We may have requeued some rqs in ublk_quiesce_queue() */
1234 blk_mq_kick_requeue_list(ub->ub_disk->queue);
1235}
1236
1237static void ublk_stop_dev(struct ublk_device *ub)
1238{
1239 mutex_lock(&ub->mutex);
1240 if (ub->dev_info.state == UBLK_S_DEV_DEAD)
1241 goto unlock;
1242 if (ublk_can_use_recovery(ub)) {
1243 if (ub->dev_info.state == UBLK_S_DEV_LIVE)
1244 __ublk_quiesce_dev(ub);
1245 ublk_unquiesce_dev(ub);
1246 }
71f28f31
ML
1247 del_gendisk(ub->ub_disk);
1248 ub->dev_info.state = UBLK_S_DEV_DEAD;
1249 ub->dev_info.ublksrv_pid = -1;
6d9e6dfd
CH
1250 put_disk(ub->ub_disk);
1251 ub->ub_disk = NULL;
71f28f31 1252 unlock:
a8ce5f52 1253 ublk_cancel_dev(ub);
71f28f31
ML
1254 mutex_unlock(&ub->mutex);
1255 cancel_delayed_work_sync(&ub->monitor_work);
1256}
1257
71f28f31
ML
1258/* device can only be started after all IOs are ready */
1259static void ublk_mark_io_ready(struct ublk_device *ub, struct ublk_queue *ubq)
1260{
1261 mutex_lock(&ub->mutex);
1262 ubq->nr_io_ready++;
1263 if (ublk_queue_ready(ubq)) {
1264 ubq->ubq_daemon = current;
1265 get_task_struct(ubq->ubq_daemon);
1266 ub->nr_queues_ready++;
73a166d9
ML
1267
1268 if (capable(CAP_SYS_ADMIN))
1269 ub->nr_privileged_daemon++;
71f28f31
ML
1270 }
1271 if (ub->nr_queues_ready == ub->dev_info.nr_hw_queues)
1272 complete_all(&ub->completion);
1273 mutex_unlock(&ub->mutex);
1274}
1275
c86019ff 1276static void ublk_handle_need_get_data(struct ublk_device *ub, int q_id,
fee32f31 1277 int tag)
c86019ff
Z
1278{
1279 struct ublk_queue *ubq = ublk_get_queue(ub, q_id);
1280 struct request *req = blk_mq_tag_to_rq(ub->tag_set.tags[q_id], tag);
1281
7d4a9317 1282 ublk_queue_cmd(ubq, req);
c86019ff
Z
1283}
1284
2d786e66
ML
1285static inline int ublk_check_cmd_op(u32 cmd_op)
1286{
1287 u32 ioc_type = _IOC_TYPE(cmd_op);
1288
e485bd9e 1289 if (!IS_ENABLED(CONFIG_BLKDEV_UBLK_LEGACY_OPCODES) && ioc_type != 'u')
2d786e66
ML
1290 return -EOPNOTSUPP;
1291
1292 if (ioc_type != 'u' && ioc_type != 0)
1293 return -EOPNOTSUPP;
1294
1295 return 0;
1296}
1297
8c68ae3b
JA
1298static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
1299 unsigned int issue_flags,
03e5cb7b 1300 const struct ublksrv_io_cmd *ub_cmd)
71f28f31 1301{
71f28f31
ML
1302 struct ublk_device *ub = cmd->file->private_data;
1303 struct ublk_queue *ubq;
1304 struct ublk_io *io;
1305 u32 cmd_op = cmd->cmd_op;
1306 unsigned tag = ub_cmd->tag;
1307 int ret = -EINVAL;
2f1e07dd 1308 struct request *req;
71f28f31
ML
1309
1310 pr_devel("%s: received: cmd op %d queue %d tag %d result %d\n",
1311 __func__, cmd->cmd_op, ub_cmd->q_id, tag,
1312 ub_cmd->result);
1313
71f28f31
ML
1314 if (ub_cmd->q_id >= ub->dev_info.nr_hw_queues)
1315 goto out;
1316
1317 ubq = ublk_get_queue(ub, ub_cmd->q_id);
1318 if (!ubq || ub_cmd->q_id != ubq->q_id)
1319 goto out;
1320
1321 if (ubq->ubq_daemon && ubq->ubq_daemon != current)
1322 goto out;
1323
1324 if (tag >= ubq->q_depth)
1325 goto out;
1326
1327 io = &ubq->ios[tag];
1328
1329 /* there is pending io cmd, something must be wrong */
1330 if (io->flags & UBLK_IO_FLAG_ACTIVE) {
1331 ret = -EBUSY;
1332 goto out;
1333 }
1334
c86019ff
Z
1335 /*
1336 * ensure that the user issues UBLK_IO_NEED_GET_DATA
1337 * iff the driver have set the UBLK_IO_FLAG_NEED_GET_DATA.
1338 */
1339 if ((!!(io->flags & UBLK_IO_FLAG_NEED_GET_DATA))
2d786e66
ML
1340 ^ (_IOC_NR(cmd_op) == UBLK_IO_NEED_GET_DATA))
1341 goto out;
1342
1343 ret = ublk_check_cmd_op(cmd_op);
1344 if (ret)
c86019ff
Z
1345 goto out;
1346
7c75661c 1347 ret = -EINVAL;
2d786e66 1348 switch (_IOC_NR(cmd_op)) {
71f28f31
ML
1349 case UBLK_IO_FETCH_REQ:
1350 /* UBLK_IO_FETCH_REQ is only allowed before queue is setup */
1351 if (ublk_queue_ready(ubq)) {
1352 ret = -EBUSY;
1353 goto out;
1354 }
1355 /*
1356 * The io is being handled by server, so COMMIT_RQ is expected
1357 * instead of FETCH_REQ
1358 */
1359 if (io->flags & UBLK_IO_FLAG_OWNED_BY_SRV)
1360 goto out;
2f1e07dd
LX
1361 /* FETCH_RQ has to provide IO buffer if NEED GET DATA is not enabled */
1362 if (!ub_cmd->addr && !ublk_need_get_data(ubq))
71f28f31
ML
1363 goto out;
1364 io->cmd = cmd;
1365 io->flags |= UBLK_IO_FLAG_ACTIVE;
1366 io->addr = ub_cmd->addr;
1367
1368 ublk_mark_io_ready(ub, ubq);
1369 break;
1370 case UBLK_IO_COMMIT_AND_FETCH_REQ:
2f1e07dd
LX
1371 req = blk_mq_tag_to_rq(ub->tag_set.tags[ub_cmd->q_id], tag);
1372 /*
1373 * COMMIT_AND_FETCH_REQ has to provide IO buffer if NEED GET DATA is
1374 * not enabled or it is Read IO.
1375 */
1376 if (!ub_cmd->addr && (!ublk_need_get_data(ubq) || req_op(req) == REQ_OP_READ))
71f28f31
ML
1377 goto out;
1378 if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV))
1379 goto out;
1380 io->addr = ub_cmd->addr;
1381 io->flags |= UBLK_IO_FLAG_ACTIVE;
1382 io->cmd = cmd;
1383 ublk_commit_completion(ub, ub_cmd);
1384 break;
c86019ff
Z
1385 case UBLK_IO_NEED_GET_DATA:
1386 if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV))
1387 goto out;
1388 io->addr = ub_cmd->addr;
1389 io->cmd = cmd;
1390 io->flags |= UBLK_IO_FLAG_ACTIVE;
fee32f31 1391 ublk_handle_need_get_data(ub, ub_cmd->q_id, ub_cmd->tag);
c86019ff 1392 break;
71f28f31
ML
1393 default:
1394 goto out;
1395 }
1396 return -EIOCBQUEUED;
1397
1398 out:
9d2789ac 1399 io_uring_cmd_done(cmd, ret, 0, issue_flags);
71f28f31
ML
1400 pr_devel("%s: complete: cmd op %d, tag %d ret %x io_flags %x\n",
1401 __func__, cmd_op, tag, ret, io->flags);
1402 return -EIOCBQUEUED;
1403}
1404
8c68ae3b
JA
1405static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
1406{
8c68ae3b
JA
1407 /*
1408 * Not necessary for async retry, but let's keep it simple and always
1409 * copy the values to avoid any potential reuse.
1410 */
03e5cb7b
LT
1411 const struct ublksrv_io_cmd *ub_src = io_uring_sqe_cmd(cmd->sqe);
1412 const struct ublksrv_io_cmd ub_cmd = {
1413 .q_id = READ_ONCE(ub_src->q_id),
1414 .tag = READ_ONCE(ub_src->tag),
1415 .result = READ_ONCE(ub_src->result),
1416 .addr = READ_ONCE(ub_src->addr)
1417 };
8c68ae3b
JA
1418
1419 return __ublk_ch_uring_cmd(cmd, issue_flags, &ub_cmd);
1420}
1421
71f28f31
ML
1422static const struct file_operations ublk_ch_fops = {
1423 .owner = THIS_MODULE,
1424 .open = ublk_ch_open,
1425 .release = ublk_ch_release,
1426 .llseek = no_llseek,
1427 .uring_cmd = ublk_ch_uring_cmd,
1428 .mmap = ublk_ch_mmap,
1429};
1430
1431static void ublk_deinit_queue(struct ublk_device *ub, int q_id)
1432{
1433 int size = ublk_queue_cmd_buf_size(ub, q_id);
1434 struct ublk_queue *ubq = ublk_get_queue(ub, q_id);
1435
1436 if (ubq->ubq_daemon)
1437 put_task_struct(ubq->ubq_daemon);
1438 if (ubq->io_cmd_buf)
1439 free_pages((unsigned long)ubq->io_cmd_buf, get_order(size));
1440}
1441
1442static int ublk_init_queue(struct ublk_device *ub, int q_id)
1443{
1444 struct ublk_queue *ubq = ublk_get_queue(ub, q_id);
1445 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO;
1446 void *ptr;
1447 int size;
1448
6d8c5afc 1449 ubq->flags = ub->dev_info.flags;
71f28f31
ML
1450 ubq->q_id = q_id;
1451 ubq->q_depth = ub->dev_info.queue_depth;
1452 size = ublk_queue_cmd_buf_size(ub, q_id);
1453
1454 ptr = (void *) __get_free_pages(gfp_flags, get_order(size));
1455 if (!ptr)
1456 return -ENOMEM;
1457
1458 ubq->io_cmd_buf = ptr;
1459 ubq->dev = ub;
1460 return 0;
1461}
1462
1463static void ublk_deinit_queues(struct ublk_device *ub)
1464{
1465 int nr_queues = ub->dev_info.nr_hw_queues;
1466 int i;
1467
1468 if (!ub->__queues)
1469 return;
1470
1471 for (i = 0; i < nr_queues; i++)
1472 ublk_deinit_queue(ub, i);
1473 kfree(ub->__queues);
1474}
1475
1476static int ublk_init_queues(struct ublk_device *ub)
1477{
1478 int nr_queues = ub->dev_info.nr_hw_queues;
1479 int depth = ub->dev_info.queue_depth;
1480 int ubq_size = sizeof(struct ublk_queue) + depth * sizeof(struct ublk_io);
1481 int i, ret = -ENOMEM;
1482
1483 ub->queue_size = ubq_size;
1484 ub->__queues = kcalloc(nr_queues, ubq_size, GFP_KERNEL);
1485 if (!ub->__queues)
1486 return ret;
1487
1488 for (i = 0; i < nr_queues; i++) {
1489 if (ublk_init_queue(ub, i))
1490 goto fail;
1491 }
1492
1493 init_completion(&ub->completion);
1494 return 0;
1495
1496 fail:
1497 ublk_deinit_queues(ub);
1498 return ret;
1499}
1500
fa9482e0 1501static int ublk_alloc_dev_number(struct ublk_device *ub, int idx)
71f28f31
ML
1502{
1503 int i = idx;
1504 int err;
1505
1506 spin_lock(&ublk_idr_lock);
1507 /* allocate id, if @id >= 0, we're requesting that specific id */
1508 if (i >= 0) {
1509 err = idr_alloc(&ublk_index_idr, ub, i, i + 1, GFP_NOWAIT);
1510 if (err == -ENOSPC)
1511 err = -EEXIST;
1512 } else {
1513 err = idr_alloc(&ublk_index_idr, ub, 0, 0, GFP_NOWAIT);
1514 }
1515 spin_unlock(&ublk_idr_lock);
1516
1517 if (err >= 0)
1518 ub->ub_number = err;
1519
1520 return err;
1521}
1522
fa9482e0 1523static void ublk_free_dev_number(struct ublk_device *ub)
71f28f31
ML
1524{
1525 spin_lock(&ublk_idr_lock);
1526 idr_remove(&ublk_index_idr, ub->ub_number);
1527 wake_up_all(&ublk_idr_wq);
1528 spin_unlock(&ublk_idr_lock);
71f28f31
ML
1529}
1530
1531static void ublk_cdev_rel(struct device *dev)
1532{
1533 struct ublk_device *ub = container_of(dev, struct ublk_device, cdev_dev);
1534
71f28f31 1535 blk_mq_free_tag_set(&ub->tag_set);
71f28f31 1536 ublk_deinit_queues(ub);
fa9482e0
CH
1537 ublk_free_dev_number(ub);
1538 mutex_destroy(&ub->mutex);
1539 kfree(ub);
71f28f31
ML
1540}
1541
1542static int ublk_add_chdev(struct ublk_device *ub)
1543{
1544 struct device *dev = &ub->cdev_dev;
1545 int minor = ub->ub_number;
1546 int ret;
1547
1548 dev->parent = ublk_misc.this_device;
1549 dev->devt = MKDEV(MAJOR(ublk_chr_devt), minor);
1550 dev->class = ublk_chr_class;
1551 dev->release = ublk_cdev_rel;
1552 device_initialize(dev);
1553
1554 ret = dev_set_name(dev, "ublkc%d", minor);
1555 if (ret)
1556 goto fail;
1557
1558 cdev_init(&ub->cdev, &ublk_ch_fops);
1559 ret = cdev_device_add(&ub->cdev, dev);
1560 if (ret)
1561 goto fail;
403ebc87
ML
1562
1563 ublks_added++;
71f28f31
ML
1564 return 0;
1565 fail:
1566 put_device(dev);
1567 return ret;
1568}
1569
1570static void ublk_stop_work_fn(struct work_struct *work)
1571{
1572 struct ublk_device *ub =
1573 container_of(work, struct ublk_device, stop_work);
1574
1575 ublk_stop_dev(ub);
1576}
1577
4bf9cbf3 1578/* align max io buffer size with PAGE_SIZE */
6d9e6dfd 1579static void ublk_align_max_io_size(struct ublk_device *ub)
71f28f31 1580{
4bf9cbf3 1581 unsigned int max_io_bytes = ub->dev_info.max_io_buf_bytes;
71f28f31 1582
4bf9cbf3
ML
1583 ub->dev_info.max_io_buf_bytes =
1584 round_down(max_io_bytes, PAGE_SIZE);
71f28f31
ML
1585}
1586
fa9482e0 1587static int ublk_add_tag_set(struct ublk_device *ub)
71f28f31 1588{
71f28f31
ML
1589 ub->tag_set.ops = &ublk_mq_ops;
1590 ub->tag_set.nr_hw_queues = ub->dev_info.nr_hw_queues;
1591 ub->tag_set.queue_depth = ub->dev_info.queue_depth;
1592 ub->tag_set.numa_node = NUMA_NO_NODE;
0edb3696 1593 ub->tag_set.cmd_size = sizeof(struct ublk_rq_data);
71f28f31
ML
1594 ub->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
1595 ub->tag_set.driver_data = ub;
fa9482e0 1596 return blk_mq_alloc_tag_set(&ub->tag_set);
71f28f31
ML
1597}
1598
1599static void ublk_remove(struct ublk_device *ub)
1600{
34d8f2be
CH
1601 ublk_stop_dev(ub);
1602 cancel_work_sync(&ub->stop_work);
bbae8d1f 1603 cancel_work_sync(&ub->quiesce_work);
71f28f31
ML
1604 cdev_device_del(&ub->cdev, &ub->cdev_dev);
1605 put_device(&ub->cdev_dev);
403ebc87 1606 ublks_added--;
71f28f31
ML
1607}
1608
1609static struct ublk_device *ublk_get_device_from_id(int idx)
1610{
1611 struct ublk_device *ub = NULL;
1612
1613 if (idx < 0)
1614 return NULL;
1615
1616 spin_lock(&ublk_idr_lock);
1617 ub = idr_find(&ublk_index_idr, idx);
1618 if (ub)
1619 ub = ublk_get_device(ub);
1620 spin_unlock(&ublk_idr_lock);
1621
1622 return ub;
1623}
1624
bfbcef03 1625static int ublk_ctrl_start_dev(struct ublk_device *ub, struct io_uring_cmd *cmd)
71f28f31 1626{
fd9b8547 1627 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
71f28f31 1628 int ublksrv_pid = (int)header->data[0];
6d9e6dfd 1629 struct gendisk *disk;
34d8f2be 1630 int ret = -EINVAL;
71f28f31
ML
1631
1632 if (ublksrv_pid <= 0)
34d8f2be
CH
1633 return -EINVAL;
1634
71f28f31
ML
1635 wait_for_completion_interruptible(&ub->completion);
1636
1637 schedule_delayed_work(&ub->monitor_work, UBLK_DAEMON_MONITOR_PERIOD);
1638
1639 mutex_lock(&ub->mutex);
6d9e6dfd
CH
1640 if (ub->dev_info.state == UBLK_S_DEV_LIVE ||
1641 test_bit(UB_STATE_USED, &ub->state)) {
71f28f31 1642 ret = -EEXIST;
34d8f2be 1643 goto out_unlock;
71f28f31 1644 }
71f28f31 1645
1972d038 1646 disk = blk_mq_alloc_disk(&ub->tag_set, NULL);
6d9e6dfd
CH
1647 if (IS_ERR(disk)) {
1648 ret = PTR_ERR(disk);
1649 goto out_unlock;
34d8f2be 1650 }
6d9e6dfd
CH
1651 sprintf(disk->disk_name, "ublkb%d", ub->ub_number);
1652 disk->fops = &ub_fops;
1653 disk->private_data = ub;
1654
34d8f2be 1655 ub->dev_info.ublksrv_pid = ublksrv_pid;
6d9e6dfd 1656 ub->ub_disk = disk;
0aa73170
ML
1657
1658 ret = ublk_apply_params(ub);
1659 if (ret)
1660 goto out_put_disk;
1661
73a166d9
ML
1662 /* don't probe partitions if any one ubq daemon is un-trusted */
1663 if (ub->nr_privileged_daemon != ub->nr_queues_ready)
1664 set_bit(GD_SUPPRESS_PART_SCAN, &disk->state);
1665
6d9e6dfd 1666 get_device(&ub->cdev_dev);
4985e7b2 1667 ub->dev_info.state = UBLK_S_DEV_LIVE;
6d9e6dfd
CH
1668 ret = add_disk(disk);
1669 if (ret) {
93d71ec8
ML
1670 /*
1671 * Has to drop the reference since ->free_disk won't be
1672 * called in case of add_disk failure.
1673 */
4985e7b2 1674 ub->dev_info.state = UBLK_S_DEV_DEAD;
93d71ec8 1675 ublk_put_device(ub);
0aa73170 1676 goto out_put_disk;
6d9e6dfd
CH
1677 }
1678 set_bit(UB_STATE_USED, &ub->state);
0aa73170
ML
1679out_put_disk:
1680 if (ret)
1681 put_disk(disk);
34d8f2be
CH
1682out_unlock:
1683 mutex_unlock(&ub->mutex);
71f28f31
ML
1684 return ret;
1685}
1686
bfbcef03
ML
1687static int ublk_ctrl_get_queue_affinity(struct ublk_device *ub,
1688 struct io_uring_cmd *cmd)
71f28f31 1689{
fd9b8547 1690 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
71f28f31 1691 void __user *argp = (void __user *)(unsigned long)header->addr;
c50061f0 1692 cpumask_var_t cpumask;
71f28f31
ML
1693 unsigned long queue;
1694 unsigned int retlen;
c50061f0 1695 unsigned int i;
bfbcef03
ML
1696 int ret;
1697
34d8f2be
CH
1698 if (header->len * BITS_PER_BYTE < nr_cpu_ids)
1699 return -EINVAL;
1700 if (header->len & (sizeof(unsigned long)-1))
1701 return -EINVAL;
1702 if (!header->addr)
1703 return -EINVAL;
71f28f31 1704
71f28f31
ML
1705 queue = header->data[0];
1706 if (queue >= ub->dev_info.nr_hw_queues)
bfbcef03 1707 return -EINVAL;
71f28f31 1708
c50061f0 1709 if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL))
bfbcef03 1710 return -ENOMEM;
c50061f0
CH
1711
1712 for_each_possible_cpu(i) {
1713 if (ub->tag_set.map[HCTX_TYPE_DEFAULT].mq_map[i] == queue)
1714 cpumask_set_cpu(i, cpumask);
71f28f31 1715 }
c50061f0
CH
1716
1717 ret = -EFAULT;
1718 retlen = min_t(unsigned short, header->len, cpumask_size());
1719 if (copy_to_user(argp, cpumask, retlen))
1720 goto out_free_cpumask;
1721 if (retlen != header->len &&
1722 clear_user(argp + retlen, header->len - retlen))
1723 goto out_free_cpumask;
1724
71f28f31 1725 ret = 0;
c50061f0
CH
1726out_free_cpumask:
1727 free_cpumask_var(cpumask);
71f28f31
ML
1728 return ret;
1729}
1730
34d8f2be 1731static inline void ublk_dump_dev_info(struct ublksrv_ctrl_dev_info *info)
71f28f31 1732{
34d8f2be 1733 pr_devel("%s: dev id %d flags %llx\n", __func__,
6d8c5afc 1734 info->dev_id, info->flags);
4bf9cbf3
ML
1735 pr_devel("\t nr_hw_queues %d queue_depth %d\n",
1736 info->nr_hw_queues, info->queue_depth);
34d8f2be
CH
1737}
1738
1739static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
1740{
fd9b8547 1741 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
34d8f2be
CH
1742 void __user *argp = (void __user *)(unsigned long)header->addr;
1743 struct ublksrv_ctrl_dev_info info;
71f28f31 1744 struct ublk_device *ub;
34d8f2be
CH
1745 int ret = -EINVAL;
1746
1747 if (header->len < sizeof(info) || !header->addr)
1748 return -EINVAL;
1749 if (header->queue_id != (u16)-1) {
1750 pr_warn("%s: queue_id is wrong %x\n",
1751 __func__, header->queue_id);
1752 return -EINVAL;
1753 }
4093cb5a 1754
34d8f2be
CH
1755 if (copy_from_user(&info, argp, sizeof(info)))
1756 return -EFAULT;
4093cb5a
ML
1757
1758 if (capable(CAP_SYS_ADMIN))
1759 info.flags &= ~UBLK_F_UNPRIVILEGED_DEV;
1760 else if (!(info.flags & UBLK_F_UNPRIVILEGED_DEV))
1761 return -EPERM;
1762
c0b79b0f
ML
1763 /*
1764 * unprivileged device can't be trusted, but RECOVERY and
1765 * RECOVERY_REISSUE still may hang error handling, so can't
1766 * support recovery features for unprivileged ublk now
1767 *
1768 * TODO: provide forward progress for RECOVERY handler, so that
1769 * unprivileged device can benefit from it
1770 */
1771 if (info.flags & UBLK_F_UNPRIVILEGED_DEV)
1772 info.flags &= ~(UBLK_F_USER_RECOVERY_REISSUE |
1773 UBLK_F_USER_RECOVERY);
1774
4093cb5a 1775 /* the created device is always owned by current user */
48a90519 1776 ublk_store_owner_uid_gid(&info.owner_uid, &info.owner_gid);
4093cb5a 1777
34d8f2be
CH
1778 if (header->dev_id != info.dev_id) {
1779 pr_warn("%s: dev id not match %u %u\n",
1780 __func__, header->dev_id, info.dev_id);
1781 return -EINVAL;
1782 }
71f28f31 1783
4093cb5a
ML
1784 ublk_dump_dev_info(&info);
1785
71f28f31
ML
1786 ret = mutex_lock_killable(&ublk_ctl_mutex);
1787 if (ret)
1788 return ret;
1789
403ebc87
ML
1790 ret = -EACCES;
1791 if (ublks_added >= ublks_max)
1792 goto out_unlock;
1793
cfee7e4d
CH
1794 ret = -ENOMEM;
1795 ub = kzalloc(sizeof(*ub), GFP_KERNEL);
1796 if (!ub)
1797 goto out_unlock;
fa9482e0
CH
1798 mutex_init(&ub->mutex);
1799 spin_lock_init(&ub->mm_lock);
bbae8d1f 1800 INIT_WORK(&ub->quiesce_work, ublk_quiesce_work_fn);
fa9482e0
CH
1801 INIT_WORK(&ub->stop_work, ublk_stop_work_fn);
1802 INIT_DELAYED_WORK(&ub->monitor_work, ublk_daemon_monitor_work);
cfee7e4d 1803
fa9482e0
CH
1804 ret = ublk_alloc_dev_number(ub, header->dev_id);
1805 if (ret < 0)
1806 goto out_free_ub;
71f28f31 1807
34d8f2be 1808 memcpy(&ub->dev_info, &info, sizeof(info));
71f28f31 1809
34d8f2be
CH
1810 /* update device id */
1811 ub->dev_info.dev_id = ub->ub_number;
1812
6d8c5afc
ML
1813 /*
1814 * 64bit flags will be copied back to userspace as feature
1815 * negotiation result, so have to clear flags which driver
1816 * doesn't support yet, then userspace can get correct flags
1817 * (features) to handle.
1818 */
1819 ub->dev_info.flags &= UBLK_F_ALL;
1820
224e858f
ML
1821 if (!IS_BUILTIN(CONFIG_BLK_DEV_UBLK))
1822 ub->dev_info.flags |= UBLK_F_URING_CMD_COMP_IN_TASK;
1823
2d786e66
ML
1824 ub->dev_info.flags |= UBLK_F_CMD_IOCTL_ENCODE;
1825
fa9482e0 1826 /* We are not ready to support zero copy */
6d8c5afc 1827 ub->dev_info.flags &= ~UBLK_F_SUPPORT_ZERO_COPY;
fa9482e0 1828
fa9482e0
CH
1829 ub->dev_info.nr_hw_queues = min_t(unsigned int,
1830 ub->dev_info.nr_hw_queues, nr_cpu_ids);
1831 ublk_align_max_io_size(ub);
1832
1833 ret = ublk_init_queues(ub);
34d8f2be 1834 if (ret)
fa9482e0 1835 goto out_free_dev_number;
34d8f2be 1836
fa9482e0
CH
1837 ret = ublk_add_tag_set(ub);
1838 if (ret)
1839 goto out_deinit_queues;
1840
1841 ret = -EFAULT;
1842 if (copy_to_user(argp, &ub->dev_info, sizeof(info)))
1843 goto out_free_tag_set;
1844
1845 /*
1846 * Add the char dev so that ublksrv daemon can be setup.
1847 * ublk_add_chdev() will cleanup everything if it fails.
1848 */
1849 ret = ublk_add_chdev(ub);
1850 goto out_unlock;
1851
1852out_free_tag_set:
1853 blk_mq_free_tag_set(&ub->tag_set);
1854out_deinit_queues:
1855 ublk_deinit_queues(ub);
1856out_free_dev_number:
1857 ublk_free_dev_number(ub);
1858out_free_ub:
1859 mutex_destroy(&ub->mutex);
1860 kfree(ub);
34d8f2be 1861out_unlock:
71f28f31 1862 mutex_unlock(&ublk_ctl_mutex);
71f28f31
ML
1863 return ret;
1864}
1865
1866static inline bool ublk_idr_freed(int id)
1867{
1868 void *ptr;
1869
1870 spin_lock(&ublk_idr_lock);
1871 ptr = idr_find(&ublk_index_idr, id);
1872 spin_unlock(&ublk_idr_lock);
1873
1874 return ptr == NULL;
1875}
1876
bfbcef03 1877static int ublk_ctrl_del_dev(struct ublk_device **p_ub)
71f28f31 1878{
bfbcef03
ML
1879 struct ublk_device *ub = *p_ub;
1880 int idx = ub->ub_number;
71f28f31
ML
1881 int ret;
1882
1883 ret = mutex_lock_killable(&ublk_ctl_mutex);
1884 if (ret)
1885 return ret;
1886
0abe39de 1887 if (!test_bit(UB_STATE_DELETED, &ub->state)) {
71f28f31 1888 ublk_remove(ub);
0abe39de 1889 set_bit(UB_STATE_DELETED, &ub->state);
71f28f31
ML
1890 }
1891
bfbcef03
ML
1892 /* Mark the reference as consumed */
1893 *p_ub = NULL;
1894 ublk_put_device(ub);
0abe39de 1895 mutex_unlock(&ublk_ctl_mutex);
71f28f31
ML
1896
1897 /*
1898 * Wait until the idr is removed, then it can be reused after
1899 * DEL_DEV command is returned.
0abe39de
ML
1900 *
1901 * If we returns because of user interrupt, future delete command
1902 * may come:
1903 *
1904 * - the device number isn't freed, this device won't or needn't
1905 * be deleted again, since UB_STATE_DELETED is set, and device
1906 * will be released after the last reference is dropped
1907 *
1908 * - the device number is freed already, we will not find this
1909 * device via ublk_get_device_from_id()
71f28f31 1910 */
0abe39de 1911 wait_event_interruptible(ublk_idr_wq, ublk_idr_freed(idx));
71f28f31 1912
0abe39de 1913 return 0;
71f28f31
ML
1914}
1915
71f28f31
ML
1916static inline void ublk_ctrl_cmd_dump(struct io_uring_cmd *cmd)
1917{
fd9b8547 1918 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
71f28f31
ML
1919
1920 pr_devel("%s: cmd_op %x, dev id %d qid %d data %llx buf %llx len %u\n",
1921 __func__, cmd->cmd_op, header->dev_id, header->queue_id,
1922 header->data[0], header->addr, header->len);
1923}
1924
bfbcef03 1925static int ublk_ctrl_stop_dev(struct ublk_device *ub)
71f28f31 1926{
34d8f2be
CH
1927 ublk_stop_dev(ub);
1928 cancel_work_sync(&ub->stop_work);
bbae8d1f 1929 cancel_work_sync(&ub->quiesce_work);
71f28f31
ML
1930
1931 return 0;
1932}
1933
bfbcef03
ML
1934static int ublk_ctrl_get_dev_info(struct ublk_device *ub,
1935 struct io_uring_cmd *cmd)
71f28f31 1936{
fd9b8547 1937 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
71f28f31 1938 void __user *argp = (void __user *)(unsigned long)header->addr;
34d8f2be
CH
1939
1940 if (header->len < sizeof(struct ublksrv_ctrl_dev_info) || !header->addr)
1941 return -EINVAL;
1942
34d8f2be 1943 if (copy_to_user(argp, &ub->dev_info, sizeof(ub->dev_info)))
bfbcef03 1944 return -EFAULT;
34d8f2be 1945
bfbcef03 1946 return 0;
34d8f2be
CH
1947}
1948
abb864d3
ML
1949/* TYPE_DEVT is readonly, so fill it up before returning to userspace */
1950static void ublk_ctrl_fill_params_devt(struct ublk_device *ub)
1951{
1952 ub->params.devt.char_major = MAJOR(ub->cdev_dev.devt);
1953 ub->params.devt.char_minor = MINOR(ub->cdev_dev.devt);
1954
1955 if (ub->ub_disk) {
1956 ub->params.devt.disk_major = MAJOR(disk_devt(ub->ub_disk));
1957 ub->params.devt.disk_minor = MINOR(disk_devt(ub->ub_disk));
1958 } else {
1959 ub->params.devt.disk_major = 0;
1960 ub->params.devt.disk_minor = 0;
1961 }
1962 ub->params.types |= UBLK_PARAM_TYPE_DEVT;
34d8f2be
CH
1963}
1964
bfbcef03
ML
1965static int ublk_ctrl_get_params(struct ublk_device *ub,
1966 struct io_uring_cmd *cmd)
0aa73170 1967{
fd9b8547 1968 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
0aa73170
ML
1969 void __user *argp = (void __user *)(unsigned long)header->addr;
1970 struct ublk_params_header ph;
0aa73170
ML
1971 int ret;
1972
1973 if (header->len <= sizeof(ph) || !header->addr)
1974 return -EINVAL;
1975
1976 if (copy_from_user(&ph, argp, sizeof(ph)))
1977 return -EFAULT;
1978
1979 if (ph.len > header->len || !ph.len)
1980 return -EINVAL;
1981
1982 if (ph.len > sizeof(struct ublk_params))
1983 ph.len = sizeof(struct ublk_params);
1984
0aa73170 1985 mutex_lock(&ub->mutex);
abb864d3 1986 ublk_ctrl_fill_params_devt(ub);
0aa73170
ML
1987 if (copy_to_user(argp, &ub->params, ph.len))
1988 ret = -EFAULT;
1989 else
1990 ret = 0;
1991 mutex_unlock(&ub->mutex);
1992
0aa73170
ML
1993 return ret;
1994}
1995
bfbcef03
ML
1996static int ublk_ctrl_set_params(struct ublk_device *ub,
1997 struct io_uring_cmd *cmd)
0aa73170 1998{
fd9b8547 1999 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
0aa73170
ML
2000 void __user *argp = (void __user *)(unsigned long)header->addr;
2001 struct ublk_params_header ph;
0aa73170
ML
2002 int ret = -EFAULT;
2003
2004 if (header->len <= sizeof(ph) || !header->addr)
2005 return -EINVAL;
2006
2007 if (copy_from_user(&ph, argp, sizeof(ph)))
2008 return -EFAULT;
2009
2010 if (ph.len > header->len || !ph.len || !ph.types)
2011 return -EINVAL;
2012
2013 if (ph.len > sizeof(struct ublk_params))
2014 ph.len = sizeof(struct ublk_params);
2015
0aa73170
ML
2016 /* parameters can only be changed when device isn't live */
2017 mutex_lock(&ub->mutex);
2018 if (ub->dev_info.state == UBLK_S_DEV_LIVE) {
2019 ret = -EACCES;
2020 } else if (copy_from_user(&ub->params, argp, ph.len)) {
2021 ret = -EFAULT;
2022 } else {
2023 /* clear all we don't support yet */
2024 ub->params.types &= UBLK_PARAM_TYPE_ALL;
2025 ret = ublk_validate_params(ub);
1d166527
ML
2026 if (ret)
2027 ub->params.types = 0;
0aa73170
ML
2028 }
2029 mutex_unlock(&ub->mutex);
0aa73170
ML
2030
2031 return ret;
2032}
2033
c732a852
Z
2034static void ublk_queue_reinit(struct ublk_device *ub, struct ublk_queue *ubq)
2035{
2036 int i;
2037
2038 WARN_ON_ONCE(!(ubq->ubq_daemon && ubq_daemon_is_dying(ubq)));
2039 /* All old ioucmds have to be completed */
2040 WARN_ON_ONCE(ubq->nr_io_ready);
2041 /* old daemon is PF_EXITING, put it now */
2042 put_task_struct(ubq->ubq_daemon);
2043 /* We have to reset it to NULL, otherwise ub won't accept new FETCH_REQ */
2044 ubq->ubq_daemon = NULL;
c0b79b0f 2045 ubq->timeout = false;
c732a852
Z
2046
2047 for (i = 0; i < ubq->q_depth; i++) {
2048 struct ublk_io *io = &ubq->ios[i];
2049
2050 /* forget everything now and be ready for new FETCH_REQ */
2051 io->flags = 0;
2052 io->cmd = NULL;
2053 io->addr = 0;
2054 }
2055}
2056
bfbcef03
ML
2057static int ublk_ctrl_start_recovery(struct ublk_device *ub,
2058 struct io_uring_cmd *cmd)
c732a852 2059{
fd9b8547 2060 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
c732a852
Z
2061 int ret = -EINVAL;
2062 int i;
2063
c732a852
Z
2064 mutex_lock(&ub->mutex);
2065 if (!ublk_can_use_recovery(ub))
2066 goto out_unlock;
2067 /*
2068 * START_RECOVERY is only allowd after:
2069 *
2070 * (1) UB_STATE_OPEN is not set, which means the dying process is exited
2071 * and related io_uring ctx is freed so file struct of /dev/ublkcX is
2072 * released.
2073 *
2074 * (2) UBLK_S_DEV_QUIESCED is set, which means the quiesce_work:
2075 * (a)has quiesced request queue
2076 * (b)has requeued every inflight rqs whose io_flags is ACTIVE
2077 * (c)has requeued/aborted every inflight rqs whose io_flags is NOT ACTIVE
2078 * (d)has completed/camceled all ioucmds owned by ther dying process
2079 */
2080 if (test_bit(UB_STATE_OPEN, &ub->state) ||
2081 ub->dev_info.state != UBLK_S_DEV_QUIESCED) {
2082 ret = -EBUSY;
2083 goto out_unlock;
2084 }
2085 pr_devel("%s: start recovery for dev id %d.\n", __func__, header->dev_id);
2086 for (i = 0; i < ub->dev_info.nr_hw_queues; i++)
2087 ublk_queue_reinit(ub, ublk_get_queue(ub, i));
2088 /* set to NULL, otherwise new ubq_daemon cannot mmap the io_cmd_buf */
2089 ub->mm = NULL;
2090 ub->nr_queues_ready = 0;
73a166d9 2091 ub->nr_privileged_daemon = 0;
c732a852
Z
2092 init_completion(&ub->completion);
2093 ret = 0;
2094 out_unlock:
2095 mutex_unlock(&ub->mutex);
c732a852
Z
2096 return ret;
2097}
2098
bfbcef03
ML
2099static int ublk_ctrl_end_recovery(struct ublk_device *ub,
2100 struct io_uring_cmd *cmd)
c732a852 2101{
fd9b8547 2102 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
c732a852 2103 int ublksrv_pid = (int)header->data[0];
c732a852
Z
2104 int ret = -EINVAL;
2105
c732a852
Z
2106 pr_devel("%s: Waiting for new ubq_daemons(nr: %d) are ready, dev id %d...\n",
2107 __func__, ub->dev_info.nr_hw_queues, header->dev_id);
2108 /* wait until new ubq_daemon sending all FETCH_REQ */
2109 wait_for_completion_interruptible(&ub->completion);
2110 pr_devel("%s: All new ubq_daemons(nr: %d) are ready, dev id %d\n",
2111 __func__, ub->dev_info.nr_hw_queues, header->dev_id);
2112
2113 mutex_lock(&ub->mutex);
2114 if (!ublk_can_use_recovery(ub))
2115 goto out_unlock;
2116
2117 if (ub->dev_info.state != UBLK_S_DEV_QUIESCED) {
2118 ret = -EBUSY;
2119 goto out_unlock;
2120 }
2121 ub->dev_info.ublksrv_pid = ublksrv_pid;
2122 pr_devel("%s: new ublksrv_pid %d, dev id %d\n",
2123 __func__, ublksrv_pid, header->dev_id);
2124 blk_mq_unquiesce_queue(ub->ub_disk->queue);
2125 pr_devel("%s: queue unquiesced, dev id %d.\n",
2126 __func__, header->dev_id);
2127 blk_mq_kick_requeue_list(ub->ub_disk->queue);
2128 ub->dev_info.state = UBLK_S_DEV_LIVE;
2129 schedule_delayed_work(&ub->monitor_work, UBLK_DAEMON_MONITOR_PERIOD);
2130 ret = 0;
2131 out_unlock:
2132 mutex_unlock(&ub->mutex);
c732a852
Z
2133 return ret;
2134}
2135
4093cb5a
ML
2136/*
2137 * All control commands are sent via /dev/ublk-control, so we have to check
2138 * the destination device's permission
2139 */
2140static int ublk_char_dev_permission(struct ublk_device *ub,
2141 const char *dev_path, int mask)
2142{
2143 int err;
2144 struct path path;
2145 struct kstat stat;
2146
2147 err = kern_path(dev_path, LOOKUP_FOLLOW, &path);
2148 if (err)
2149 return err;
2150
2151 err = vfs_getattr(&path, &stat, STATX_TYPE, AT_STATX_SYNC_AS_STAT);
2152 if (err)
2153 goto exit;
2154
2155 err = -EPERM;
2156 if (stat.rdev != ub->cdev_dev.devt || !S_ISCHR(stat.mode))
2157 goto exit;
2158
5b0ed596 2159 err = inode_permission(&nop_mnt_idmap,
4093cb5a
ML
2160 d_backing_inode(path.dentry), mask);
2161exit:
2162 path_put(&path);
2163 return err;
2164}
2165
2166static int ublk_ctrl_uring_cmd_permission(struct ublk_device *ub,
2167 struct io_uring_cmd *cmd)
2168{
fd9b8547 2169 struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)io_uring_sqe_cmd(cmd->sqe);
4093cb5a
ML
2170 bool unprivileged = ub->dev_info.flags & UBLK_F_UNPRIVILEGED_DEV;
2171 void __user *argp = (void __user *)(unsigned long)header->addr;
2172 char *dev_path = NULL;
2173 int ret = 0;
2174 int mask;
2175
2176 if (!unprivileged) {
2177 if (!capable(CAP_SYS_ADMIN))
2178 return -EPERM;
2179 /*
2180 * The new added command of UBLK_CMD_GET_DEV_INFO2 includes
2181 * char_dev_path in payload too, since userspace may not
2182 * know if the specified device is created as unprivileged
2183 * mode.
2184 */
2d786e66 2185 if (_IOC_NR(cmd->cmd_op) != UBLK_CMD_GET_DEV_INFO2)
4093cb5a
ML
2186 return 0;
2187 }
2188
2189 /*
2190 * User has to provide the char device path for unprivileged ublk
2191 *
2192 * header->addr always points to the dev path buffer, and
2193 * header->dev_path_len records length of dev path buffer.
2194 */
2195 if (!header->dev_path_len || header->dev_path_len > PATH_MAX)
2196 return -EINVAL;
2197
2198 if (header->len < header->dev_path_len)
2199 return -EINVAL;
2200
2201 dev_path = kmalloc(header->dev_path_len + 1, GFP_KERNEL);
2202 if (!dev_path)
2203 return -ENOMEM;
2204
2205 ret = -EFAULT;
2206 if (copy_from_user(dev_path, argp, header->dev_path_len))
2207 goto exit;
2208 dev_path[header->dev_path_len] = 0;
2209
2210 ret = -EINVAL;
2d786e66 2211 switch (_IOC_NR(cmd->cmd_op)) {
4093cb5a
ML
2212 case UBLK_CMD_GET_DEV_INFO:
2213 case UBLK_CMD_GET_DEV_INFO2:
2214 case UBLK_CMD_GET_QUEUE_AFFINITY:
2215 case UBLK_CMD_GET_PARAMS:
2216 mask = MAY_READ;
2217 break;
2218 case UBLK_CMD_START_DEV:
2219 case UBLK_CMD_STOP_DEV:
2220 case UBLK_CMD_ADD_DEV:
2221 case UBLK_CMD_DEL_DEV:
2222 case UBLK_CMD_SET_PARAMS:
2223 case UBLK_CMD_START_USER_RECOVERY:
2224 case UBLK_CMD_END_USER_RECOVERY:
2225 mask = MAY_READ | MAY_WRITE;
2226 break;
2227 default:
2228 goto exit;
2229 }
2230
2231 ret = ublk_char_dev_permission(ub, dev_path, mask);
2232 if (!ret) {
2233 header->len -= header->dev_path_len;
2234 header->addr += header->dev_path_len;
2235 }
2236 pr_devel("%s: dev id %d cmd_op %x uid %d gid %d path %s ret %d\n",
2237 __func__, ub->ub_number, cmd->cmd_op,
2238 ub->dev_info.owner_uid, ub->dev_info.owner_gid,
2239 dev_path, ret);
2240exit:
2241 kfree(dev_path);
c732a852
Z
2242 return ret;
2243}
2244
34d8f2be
CH
2245static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd,
2246 unsigned int issue_flags)
2247{
fd9b8547 2248 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
bfbcef03 2249 struct ublk_device *ub = NULL;
2d786e66 2250 u32 cmd_op = cmd->cmd_op;
71f28f31
ML
2251 int ret = -EINVAL;
2252
fa8e442e
ML
2253 if (issue_flags & IO_URING_F_NONBLOCK)
2254 return -EAGAIN;
2255
71f28f31
ML
2256 ublk_ctrl_cmd_dump(cmd);
2257
2258 if (!(issue_flags & IO_URING_F_SQE128))
2259 goto out;
2260
2d786e66
ML
2261 ret = ublk_check_cmd_op(cmd_op);
2262 if (ret)
2263 goto out;
2264
2265 if (_IOC_NR(cmd_op) != UBLK_CMD_ADD_DEV) {
bfbcef03
ML
2266 ret = -ENODEV;
2267 ub = ublk_get_device_from_id(header->dev_id);
2268 if (!ub)
2269 goto out;
4093cb5a
ML
2270
2271 ret = ublk_ctrl_uring_cmd_permission(ub, cmd);
2d786e66
ML
2272 if (ret)
2273 goto put_dev;
bfbcef03
ML
2274 }
2275
2d786e66 2276 switch (_IOC_NR(cmd_op)) {
71f28f31 2277 case UBLK_CMD_START_DEV:
bfbcef03 2278 ret = ublk_ctrl_start_dev(ub, cmd);
71f28f31
ML
2279 break;
2280 case UBLK_CMD_STOP_DEV:
bfbcef03 2281 ret = ublk_ctrl_stop_dev(ub);
71f28f31
ML
2282 break;
2283 case UBLK_CMD_GET_DEV_INFO:
4093cb5a 2284 case UBLK_CMD_GET_DEV_INFO2:
bfbcef03 2285 ret = ublk_ctrl_get_dev_info(ub, cmd);
71f28f31
ML
2286 break;
2287 case UBLK_CMD_ADD_DEV:
34d8f2be 2288 ret = ublk_ctrl_add_dev(cmd);
71f28f31
ML
2289 break;
2290 case UBLK_CMD_DEL_DEV:
bfbcef03 2291 ret = ublk_ctrl_del_dev(&ub);
71f28f31
ML
2292 break;
2293 case UBLK_CMD_GET_QUEUE_AFFINITY:
bfbcef03 2294 ret = ublk_ctrl_get_queue_affinity(ub, cmd);
71f28f31 2295 break;
0aa73170 2296 case UBLK_CMD_GET_PARAMS:
bfbcef03 2297 ret = ublk_ctrl_get_params(ub, cmd);
0aa73170
ML
2298 break;
2299 case UBLK_CMD_SET_PARAMS:
bfbcef03 2300 ret = ublk_ctrl_set_params(ub, cmd);
0aa73170 2301 break;
c732a852 2302 case UBLK_CMD_START_USER_RECOVERY:
bfbcef03 2303 ret = ublk_ctrl_start_recovery(ub, cmd);
c732a852
Z
2304 break;
2305 case UBLK_CMD_END_USER_RECOVERY:
bfbcef03 2306 ret = ublk_ctrl_end_recovery(ub, cmd);
c732a852 2307 break;
71f28f31 2308 default:
bfbcef03 2309 ret = -ENOTSUPP;
71f28f31 2310 break;
6b1439d2 2311 }
4093cb5a
ML
2312
2313 put_dev:
bfbcef03
ML
2314 if (ub)
2315 ublk_put_device(ub);
71f28f31 2316 out:
9d2789ac 2317 io_uring_cmd_done(cmd, ret, 0, issue_flags);
71f28f31
ML
2318 pr_devel("%s: cmd done ret %d cmd_op %x, dev id %d qid %d\n",
2319 __func__, ret, cmd->cmd_op, header->dev_id, header->queue_id);
2320 return -EIOCBQUEUED;
2321}
2322
2323static const struct file_operations ublk_ctl_fops = {
2324 .open = nonseekable_open,
2325 .uring_cmd = ublk_ctrl_uring_cmd,
2326 .owner = THIS_MODULE,
2327 .llseek = noop_llseek,
2328};
2329
2330static struct miscdevice ublk_misc = {
2331 .minor = MISC_DYNAMIC_MINOR,
2332 .name = "ublk-control",
2333 .fops = &ublk_ctl_fops,
2334};
2335
2336static int __init ublk_init(void)
2337{
2338 int ret;
2339
2340 init_waitqueue_head(&ublk_idr_wq);
2341
2342 ret = misc_register(&ublk_misc);
2343 if (ret)
2344 return ret;
2345
2346 ret = alloc_chrdev_region(&ublk_chr_devt, 0, UBLK_MINORS, "ublk-char");
2347 if (ret)
2348 goto unregister_mis;
2349
1aaba11d 2350 ublk_chr_class = class_create("ublk-char");
71f28f31
ML
2351 if (IS_ERR(ublk_chr_class)) {
2352 ret = PTR_ERR(ublk_chr_class);
2353 goto free_chrdev_region;
2354 }
2355 return 0;
2356
2357free_chrdev_region:
2358 unregister_chrdev_region(ublk_chr_devt, UBLK_MINORS);
2359unregister_mis:
2360 misc_deregister(&ublk_misc);
2361 return ret;
2362}
2363
2364static void __exit ublk_exit(void)
2365{
2366 struct ublk_device *ub;
2367 int id;
2368
71f28f31
ML
2369 idr_for_each_entry(&ublk_index_idr, ub, id)
2370 ublk_remove(ub);
2371
8e4ff684
ML
2372 class_destroy(ublk_chr_class);
2373 misc_deregister(&ublk_misc);
2374
71f28f31
ML
2375 idr_destroy(&ublk_index_idr);
2376 unregister_chrdev_region(ublk_chr_devt, UBLK_MINORS);
2377}
2378
2379module_init(ublk_init);
2380module_exit(ublk_exit);
2381
403ebc87
ML
2382module_param(ublks_max, int, 0444);
2383MODULE_PARM_DESC(ublks_max, "max number of ublk devices allowed to add(default: 64)");
2384
71f28f31
ML
2385MODULE_AUTHOR("Ming Lei <ming.lei@redhat.com>");
2386MODULE_LICENSE("GPL");