projects/linux·blob v6.3 · refs

641 lines · 16.7 KiB

1// SPDX-License-Identifier: GPL-2.0
2#include <linux/kernel.h>
3#include <linux/errno.h>
4#include <linux/file.h>
5#include <linux/io_uring.h>
6
7#include <trace/events/io_uring.h>
8
9#include <uapi/linux/io_uring.h>
10
11#include "io_uring.h"
12#include "refs.h"
13#include "cancel.h"
14#include "timeout.h"
15
16struct io_timeout {
17 struct file *file;
18 u32 off;
19 u32 target_seq;
20 struct list_head list;
21 /* head of the link, used by linked timeouts only */
22 struct io_kiocb *head;
23 /* for linked completions */
24 struct io_kiocb *prev;
25};
26
27struct io_timeout_rem {
28 struct file *file;
29 u64 addr;
30
31 /* timeout update */
32 struct timespec64 ts;
33 u32 flags;
34 bool ltimeout;
35};
36
37static inline bool io_is_timeout_noseq(struct io_kiocb *req)
38{
39 struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
40
41 return !timeout->off;
42}
43
44static inline void io_put_req(struct io_kiocb *req)
45{
46 if (req_ref_put_and_test(req)) {
47 io_queue_next(req);
48 io_free_req(req);
49 }
50}
51
52static bool io_kill_timeout(struct io_kiocb *req, int status)
53 __must_hold(&req->ctx->timeout_lock)
54{
55 struct io_timeout_data *io = req->async_data;
56
57 if (hrtimer_try_to_cancel(&io->timer) != -1) {
58 struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
59
60 if (status)
61 req_set_fail(req);
62 atomic_set(&req->ctx->cq_timeouts,
63 atomic_read(&req->ctx->cq_timeouts) + 1);
64 list_del_init(&timeout->list);
65 io_req_queue_tw_complete(req, status);
66 return true;
67 }
68 return false;
69}
70
71__cold void io_flush_timeouts(struct io_ring_ctx *ctx)
72{
73 u32 seq;
74 struct io_timeout *timeout, *tmp;
75
76 spin_lock_irq(&ctx->timeout_lock);
77 seq = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts);
78
79 list_for_each_entry_safe(timeout, tmp, &ctx->timeout_list, list) {
80 struct io_kiocb *req = cmd_to_io_kiocb(timeout);
81 u32 events_needed, events_got;
82
83 if (io_is_timeout_noseq(req))
84 break;
85
86 /*
87 * Since seq can easily wrap around over time, subtract
88 * the last seq at which timeouts were flushed before comparing.
89 * Assuming not more than 2^31-1 events have happened since,
90 * these subtractions won't have wrapped, so we can check if
91 * target is in [last_seq, current_seq] by comparing the two.
92 */
93 events_needed = timeout->target_seq - ctx->cq_last_tm_flush;
94 events_got = seq - ctx->cq_last_tm_flush;
95 if (events_got < events_needed)
96 break;
97
98 io_kill_timeout(req, 0);
99 }
100 ctx->cq_last_tm_flush = seq;
101 spin_unlock_irq(&ctx->timeout_lock);
102}
103
104static void io_req_tw_fail_links(struct io_kiocb *link, bool *locked)
105{
106 io_tw_lock(link->ctx, locked);
107 while (link) {
108 struct io_kiocb *nxt = link->link;
109 long res = -ECANCELED;
110
111 if (link->flags & REQ_F_FAIL)
112 res = link->cqe.res;
113 link->link = NULL;
114 io_req_set_res(link, res, 0);
115 io_req_task_complete(link, locked);
116 link = nxt;
117 }
118}
119
120static void io_fail_links(struct io_kiocb *req)
121 __must_hold(&req->ctx->completion_lock)
122{
123 struct io_kiocb *link = req->link;
124 bool ignore_cqes = req->flags & REQ_F_SKIP_LINK_CQES;
125
126 if (!link)
127 return;
128
129 while (link) {
130 if (ignore_cqes)
131 link->flags |= REQ_F_CQE_SKIP;
132 else
133 link->flags &= ~REQ_F_CQE_SKIP;
134 trace_io_uring_fail_link(req, link);
135 link = link->link;
136 }
137
138 link = req->link;
139 link->io_task_work.func = io_req_tw_fail_links;
140 io_req_task_work_add(link);
141 req->link = NULL;
142}
143
144static inline void io_remove_next_linked(struct io_kiocb *req)
145{
146 struct io_kiocb *nxt = req->link;
147
148 req->link = nxt->link;
149 nxt->link = NULL;
150}
151
152void io_disarm_next(struct io_kiocb *req)
153 __must_hold(&req->ctx->completion_lock)
154{
155 struct io_kiocb *link = NULL;
156
157 if (req->flags & REQ_F_ARM_LTIMEOUT) {
158 link = req->link;
159 req->flags &= ~REQ_F_ARM_LTIMEOUT;
160 if (link && link->opcode == IORING_OP_LINK_TIMEOUT) {
161 io_remove_next_linked(req);
162 io_req_queue_tw_complete(link, -ECANCELED);
163 }
164 } else if (req->flags & REQ_F_LINK_TIMEOUT) {
165 struct io_ring_ctx *ctx = req->ctx;
166
167 spin_lock_irq(&ctx->timeout_lock);
168 link = io_disarm_linked_timeout(req);
169 spin_unlock_irq(&ctx->timeout_lock);
170 if (link)
171 io_req_queue_tw_complete(link, -ECANCELED);
172 }
173 if (unlikely((req->flags & REQ_F_FAIL) &&
174 !(req->flags & REQ_F_HARDLINK)))
175 io_fail_links(req);
176}
177
178struct io_kiocb *__io_disarm_linked_timeout(struct io_kiocb *req,
179 struct io_kiocb *link)
180 __must_hold(&req->ctx->completion_lock)
181 __must_hold(&req->ctx->timeout_lock)
182{
183 struct io_timeout_data *io = link->async_data;
184 struct io_timeout *timeout = io_kiocb_to_cmd(link, struct io_timeout);
185
186 io_remove_next_linked(req);
187 timeout->head = NULL;
188 if (hrtimer_try_to_cancel(&io->timer) != -1) {
189 list_del(&timeout->list);
190 return link;
191 }
192
193 return NULL;
194}
195
196static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
197{
198 struct io_timeout_data *data = container_of(timer,
199 struct io_timeout_data, timer);
200 struct io_kiocb *req = data->req;
201 struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
202 struct io_ring_ctx *ctx = req->ctx;
203 unsigned long flags;
204
205 spin_lock_irqsave(&ctx->timeout_lock, flags);
206 list_del_init(&timeout->list);
207 atomic_set(&req->ctx->cq_timeouts,
208 atomic_read(&req->ctx->cq_timeouts) + 1);
209 spin_unlock_irqrestore(&ctx->timeout_lock, flags);
210
211 if (!(data->flags & IORING_TIMEOUT_ETIME_SUCCESS))
212 req_set_fail(req);
213
214 io_req_set_res(req, -ETIME, 0);
215 req->io_task_work.func = io_req_task_complete;
216 io_req_task_work_add(req);
217 return HRTIMER_NORESTART;
218}
219
220static struct io_kiocb *io_timeout_extract(struct io_ring_ctx *ctx,
221 struct io_cancel_data *cd)
222 __must_hold(&ctx->timeout_lock)
223{
224 struct io_timeout *timeout;
225 struct io_timeout_data *io;
226 struct io_kiocb *req = NULL;
227
228 list_for_each_entry(timeout, &ctx->timeout_list, list) {
229 struct io_kiocb *tmp = cmd_to_io_kiocb(timeout);
230
231 if (!(cd->flags & IORING_ASYNC_CANCEL_ANY) &&
232 cd->data != tmp->cqe.user_data)
233 continue;
234 if (cd->flags & (IORING_ASYNC_CANCEL_ALL|IORING_ASYNC_CANCEL_ANY)) {
235 if (cd->seq == tmp->work.cancel_seq)
236 continue;
237 tmp->work.cancel_seq = cd->seq;
238 }
239 req = tmp;
240 break;
241 }
242 if (!req)
243 return ERR_PTR(-ENOENT);
244
245 io = req->async_data;
246 if (hrtimer_try_to_cancel(&io->timer) == -1)
247 return ERR_PTR(-EALREADY);
248 timeout = io_kiocb_to_cmd(req, struct io_timeout);
249 list_del_init(&timeout->list);
250 return req;
251}
252
253int io_timeout_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd)
254 __must_hold(&ctx->completion_lock)
255{
256 struct io_kiocb *req;
257
258 spin_lock_irq(&ctx->timeout_lock);
259 req = io_timeout_extract(ctx, cd);
260 spin_unlock_irq(&ctx->timeout_lock);
261
262 if (IS_ERR(req))
263 return PTR_ERR(req);
264 io_req_task_queue_fail(req, -ECANCELED);
265 return 0;
266}
267
268static void io_req_task_link_timeout(struct io_kiocb *req, bool *locked)
269{
270 unsigned issue_flags = *locked ? 0 : IO_URING_F_UNLOCKED;
271 struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
272 struct io_kiocb *prev = timeout->prev;
273 int ret = -ENOENT;
274
275 if (prev) {
276 if (!(req->task->flags & PF_EXITING)) {
277 struct io_cancel_data cd = {
278 .ctx = req->ctx,
279 .data = prev->cqe.user_data,
280 };
281
282 ret = io_try_cancel(req->task->io_uring, &cd, issue_flags);
283 }
284 io_req_set_res(req, ret ?: -ETIME, 0);
285 io_req_task_complete(req, locked);
286 io_put_req(prev);
287 } else {
288 io_req_set_res(req, -ETIME, 0);
289 io_req_task_complete(req, locked);
290 }
291}
292
293static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer)
294{
295 struct io_timeout_data *data = container_of(timer,
296 struct io_timeout_data, timer);
297 struct io_kiocb *prev, *req = data->req;
298 struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
299 struct io_ring_ctx *ctx = req->ctx;
300 unsigned long flags;
301
302 spin_lock_irqsave(&ctx->timeout_lock, flags);
303 prev = timeout->head;
304 timeout->head = NULL;
305
306 /*
307 * We don't expect the list to be empty, that will only happen if we
308 * race with the completion of the linked work.
309 */
310 if (prev) {
311 io_remove_next_linked(prev);
312 if (!req_ref_inc_not_zero(prev))
313 prev = NULL;
314 }
315 list_del(&timeout->list);
316 timeout->prev = prev;
317 spin_unlock_irqrestore(&ctx->timeout_lock, flags);
318
319 req->io_task_work.func = io_req_task_link_timeout;
320 io_req_task_work_add(req);
321 return HRTIMER_NORESTART;
322}
323
324static clockid_t io_timeout_get_clock(struct io_timeout_data *data)
325{
326 switch (data->flags & IORING_TIMEOUT_CLOCK_MASK) {
327 case IORING_TIMEOUT_BOOTTIME:
328 return CLOCK_BOOTTIME;
329 case IORING_TIMEOUT_REALTIME:
330 return CLOCK_REALTIME;
331 default:
332 /* can't happen, vetted at prep time */
333 WARN_ON_ONCE(1);
334 fallthrough;
335 case 0:
336 return CLOCK_MONOTONIC;
337 }
338}
339
340static int io_linked_timeout_update(struct io_ring_ctx *ctx, __u64 user_data,
341 struct timespec64 *ts, enum hrtimer_mode mode)
342 __must_hold(&ctx->timeout_lock)
343{
344 struct io_timeout_data *io;
345 struct io_timeout *timeout;
346 struct io_kiocb *req = NULL;
347
348 list_for_each_entry(timeout, &ctx->ltimeout_list, list) {
349 struct io_kiocb *tmp = cmd_to_io_kiocb(timeout);
350
351 if (user_data == tmp->cqe.user_data) {
352 req = tmp;
353 break;
354 }
355 }
356 if (!req)
357 return -ENOENT;
358
359 io = req->async_data;
360 if (hrtimer_try_to_cancel(&io->timer) == -1)
361 return -EALREADY;
362 hrtimer_init(&io->timer, io_timeout_get_clock(io), mode);
363 io->timer.function = io_link_timeout_fn;
364 hrtimer_start(&io->timer, timespec64_to_ktime(*ts), mode);
365 return 0;
366}
367
368static int io_timeout_update(struct io_ring_ctx *ctx, __u64 user_data,
369 struct timespec64 *ts, enum hrtimer_mode mode)
370 __must_hold(&ctx->timeout_lock)
371{
372 struct io_cancel_data cd = { .data = user_data, };
373 struct io_kiocb *req = io_timeout_extract(ctx, &cd);
374 struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
375 struct io_timeout_data *data;
376
377 if (IS_ERR(req))
378 return PTR_ERR(req);
379
380 timeout->off = 0; /* noseq */
381 data = req->async_data;
382 list_add_tail(&timeout->list, &ctx->timeout_list);
383 hrtimer_init(&data->timer, io_timeout_get_clock(data), mode);
384 data->timer.function = io_timeout_fn;
385 hrtimer_start(&data->timer, timespec64_to_ktime(*ts), mode);
386 return 0;
387}
388
389int io_timeout_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
390{
391 struct io_timeout_rem *tr = io_kiocb_to_cmd(req, struct io_timeout_rem);
392
393 if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
394 return -EINVAL;
395 if (sqe->buf_index || sqe->len || sqe->splice_fd_in)
396 return -EINVAL;
397
398 tr->ltimeout = false;
399 tr->addr = READ_ONCE(sqe->addr);
400 tr->flags = READ_ONCE(sqe->timeout_flags);
401 if (tr->flags & IORING_TIMEOUT_UPDATE_MASK) {
402 if (hweight32(tr->flags & IORING_TIMEOUT_CLOCK_MASK) > 1)
403 return -EINVAL;
404 if (tr->flags & IORING_LINK_TIMEOUT_UPDATE)
405 tr->ltimeout = true;
406 if (tr->flags & ~(IORING_TIMEOUT_UPDATE_MASK|IORING_TIMEOUT_ABS))
407 return -EINVAL;
408 if (get_timespec64(&tr->ts, u64_to_user_ptr(sqe->addr2)))
409 return -EFAULT;
410 if (tr->ts.tv_sec < 0 || tr->ts.tv_nsec < 0)
411 return -EINVAL;
412 } else if (tr->flags) {
413 /* timeout removal doesn't support flags */
414 return -EINVAL;
415 }
416
417 return 0;
418}
419
420static inline enum hrtimer_mode io_translate_timeout_mode(unsigned int flags)
421{
422 return (flags & IORING_TIMEOUT_ABS) ? HRTIMER_MODE_ABS
423 : HRTIMER_MODE_REL;
424}
425
426/*
427 * Remove or update an existing timeout command
428 */
429int io_timeout_remove(struct io_kiocb *req, unsigned int issue_flags)
430{
431 struct io_timeout_rem *tr = io_kiocb_to_cmd(req, struct io_timeout_rem);
432 struct io_ring_ctx *ctx = req->ctx;
433 int ret;
434
435 if (!(tr->flags & IORING_TIMEOUT_UPDATE)) {
436 struct io_cancel_data cd = { .data = tr->addr, };
437
438 spin_lock(&ctx->completion_lock);
439 ret = io_timeout_cancel(ctx, &cd);
440 spin_unlock(&ctx->completion_lock);
441 } else {
442 enum hrtimer_mode mode = io_translate_timeout_mode(tr->flags);
443
444 spin_lock_irq(&ctx->timeout_lock);
445 if (tr->ltimeout)
446 ret = io_linked_timeout_update(ctx, tr->addr, &tr->ts, mode);
447 else
448 ret = io_timeout_update(ctx, tr->addr, &tr->ts, mode);
449 spin_unlock_irq(&ctx->timeout_lock);
450 }
451
452 if (ret < 0)
453 req_set_fail(req);
454 io_req_set_res(req, ret, 0);
455 return IOU_OK;
456}
457
458static int __io_timeout_prep(struct io_kiocb *req,
459 const struct io_uring_sqe *sqe,
460 bool is_timeout_link)
461{
462 struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
463 struct io_timeout_data *data;
464 unsigned flags;
465 u32 off = READ_ONCE(sqe->off);
466
467 if (sqe->buf_index || sqe->len != 1 || sqe->splice_fd_in)
468 return -EINVAL;
469 if (off && is_timeout_link)
470 return -EINVAL;
471 flags = READ_ONCE(sqe->timeout_flags);
472 if (flags & ~(IORING_TIMEOUT_ABS | IORING_TIMEOUT_CLOCK_MASK |
473 IORING_TIMEOUT_ETIME_SUCCESS))
474 return -EINVAL;
475 /* more than one clock specified is invalid, obviously */
476 if (hweight32(flags & IORING_TIMEOUT_CLOCK_MASK) > 1)
477 return -EINVAL;
478
479 INIT_LIST_HEAD(&timeout->list);
480 timeout->off = off;
481 if (unlikely(off && !req->ctx->off_timeout_used))
482 req->ctx->off_timeout_used = true;
483
484 if (WARN_ON_ONCE(req_has_async_data(req)))
485 return -EFAULT;
486 if (io_alloc_async_data(req))
487 return -ENOMEM;
488
489 data = req->async_data;
490 data->req = req;
491 data->flags = flags;
492
493 if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr)))
494 return -EFAULT;
495
496 if (data->ts.tv_sec < 0 || data->ts.tv_nsec < 0)
497 return -EINVAL;
498
499 INIT_LIST_HEAD(&timeout->list);
500 data->mode = io_translate_timeout_mode(flags);
501 hrtimer_init(&data->timer, io_timeout_get_clock(data), data->mode);
502
503 if (is_timeout_link) {
504 struct io_submit_link *link = &req->ctx->submit_state.link;
505
506 if (!link->head)
507 return -EINVAL;
508 if (link->last->opcode == IORING_OP_LINK_TIMEOUT)
509 return -EINVAL;
510 timeout->head = link->last;
511 link->last->flags |= REQ_F_ARM_LTIMEOUT;
512 }
513 return 0;
514}
515
516int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
517{
518 return __io_timeout_prep(req, sqe, false);
519}
520
521int io_link_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
522{
523 return __io_timeout_prep(req, sqe, true);
524}
525
526int io_timeout(struct io_kiocb *req, unsigned int issue_flags)
527{
528 struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
529 struct io_ring_ctx *ctx = req->ctx;
530 struct io_timeout_data *data = req->async_data;
531 struct list_head *entry;
532 u32 tail, off = timeout->off;
533
534 spin_lock_irq(&ctx->timeout_lock);
535
536 /*
537 * sqe->off holds how many events that need to occur for this
538 * timeout event to be satisfied. If it isn't set, then this is
539 * a pure timeout request, sequence isn't used.
540 */
541 if (io_is_timeout_noseq(req)) {
542 entry = ctx->timeout_list.prev;
543 goto add;
544 }
545
546 tail = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts);
547 timeout->target_seq = tail + off;
548
549 /* Update the last seq here in case io_flush_timeouts() hasn't.
550 * This is safe because ->completion_lock is held, and submissions
551 * and completions are never mixed in the same ->completion_lock section.
552 */
553 ctx->cq_last_tm_flush = tail;
554
555 /*
556 * Insertion sort, ensuring the first entry in the list is always
557 * the one we need first.
558 */
559 list_for_each_prev(entry, &ctx->timeout_list) {
560 struct io_timeout *nextt = list_entry(entry, struct io_timeout, list);
561 struct io_kiocb *nxt = cmd_to_io_kiocb(nextt);
562
563 if (io_is_timeout_noseq(nxt))
564 continue;
565 /* nxt.seq is behind @tail, otherwise would've been completed */
566 if (off >= nextt->target_seq - tail)
567 break;
568 }
569add:
570 list_add(&timeout->list, entry);
571 data->timer.function = io_timeout_fn;
572 hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode);
573 spin_unlock_irq(&ctx->timeout_lock);
574 return IOU_ISSUE_SKIP_COMPLETE;
575}
576
577void io_queue_linked_timeout(struct io_kiocb *req)
578{
579 struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
580 struct io_ring_ctx *ctx = req->ctx;
581
582 spin_lock_irq(&ctx->timeout_lock);
583 /*
584 * If the back reference is NULL, then our linked request finished
585 * before we got a chance to setup the timer
586 */
587 if (timeout->head) {
588 struct io_timeout_data *data = req->async_data;
589
590 data->timer.function = io_link_timeout_fn;
591 hrtimer_start(&data->timer, timespec64_to_ktime(data->ts),
592 data->mode);
593 list_add_tail(&timeout->list, &ctx->ltimeout_list);
594 }
595 spin_unlock_irq(&ctx->timeout_lock);
596 /* drop submission reference */
597 io_put_req(req);
598}
599
600static bool io_match_task(struct io_kiocb *head, struct task_struct *task,
601 bool cancel_all)
602 __must_hold(&req->ctx->timeout_lock)
603{
604 struct io_kiocb *req;
605
606 if (task && head->task != task)
607 return false;
608 if (cancel_all)
609 return true;
610
611 io_for_each_link(req, head) {
612 if (req->flags & REQ_F_INFLIGHT)
613 return true;
614 }
615 return false;
616}
617
618/* Returns true if we found and killed one or more timeouts */
619__cold bool io_kill_timeouts(struct io_ring_ctx *ctx, struct task_struct *tsk,
620 bool cancel_all)
621{
622 struct io_timeout *timeout, *tmp;
623 int canceled = 0;
624
625 /*
626 * completion_lock is needed for io_match_task(). Take it before
627 * timeout_lockfirst to keep locking ordering.
628 */
629 spin_lock(&ctx->completion_lock);
630 spin_lock_irq(&ctx->timeout_lock);
631 list_for_each_entry_safe(timeout, tmp, &ctx->timeout_list, list) {
632 struct io_kiocb *req = cmd_to_io_kiocb(timeout);
633
634 if (io_match_task(req, tsk, cancel_all) &&
635 io_kill_timeout(req, -ECANCELED))
636 canceled++;
637 }
638 spin_unlock_irq(&ctx->timeout_lock);
639 spin_unlock(&ctx->completion_lock);
640 return canceled != 0;
641}