xref: /linux/io_uring/timeout.c (revision a9c83a0ab66a5b02e914daed502fb8d3a8d3d619)
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 
16 struct io_timeout {
17 	struct file			*file;
18 	u32				off;
19 	u32				target_seq;
20 	u32				repeats;
21 	struct list_head		list;
22 	/* head of the link, used by linked timeouts only */
23 	struct io_kiocb			*head;
24 	/* for linked completions */
25 	struct io_kiocb			*prev;
26 };
27 
28 struct io_timeout_rem {
29 	struct file			*file;
30 	u64				addr;
31 
32 	/* timeout update */
33 	struct timespec64		ts;
34 	u32				flags;
35 	bool				ltimeout;
36 };
37 
38 static inline bool io_is_timeout_noseq(struct io_kiocb *req)
39 {
40 	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
41 	struct io_timeout_data *data = req->async_data;
42 
43 	return !timeout->off || data->flags & IORING_TIMEOUT_MULTISHOT;
44 }
45 
46 static inline void io_put_req(struct io_kiocb *req)
47 {
48 	if (req_ref_put_and_test(req)) {
49 		io_queue_next(req);
50 		io_free_req(req);
51 	}
52 }
53 
54 static inline bool io_timeout_finish(struct io_timeout *timeout,
55 				     struct io_timeout_data *data)
56 {
57 	if (!(data->flags & IORING_TIMEOUT_MULTISHOT))
58 		return true;
59 
60 	if (!timeout->off || (timeout->repeats && --timeout->repeats))
61 		return false;
62 
63 	return true;
64 }
65 
66 static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer);
67 
68 static void io_timeout_complete(struct io_kiocb *req, struct io_tw_state *ts)
69 {
70 	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
71 	struct io_timeout_data *data = req->async_data;
72 	struct io_ring_ctx *ctx = req->ctx;
73 
74 	if (!io_timeout_finish(timeout, data)) {
75 		if (io_req_post_cqe(req, -ETIME, IORING_CQE_F_MORE)) {
76 			/* re-arm timer */
77 			raw_spin_lock_irq(&ctx->timeout_lock);
78 			list_add(&timeout->list, ctx->timeout_list.prev);
79 			hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode);
80 			raw_spin_unlock_irq(&ctx->timeout_lock);
81 			return;
82 		}
83 	}
84 
85 	io_req_task_complete(req, ts);
86 }
87 
88 static __cold bool io_flush_killed_timeouts(struct list_head *list, int err)
89 {
90 	if (list_empty(list))
91 		return false;
92 
93 	while (!list_empty(list)) {
94 		struct io_timeout *timeout;
95 		struct io_kiocb *req;
96 
97 		timeout = list_first_entry(list, struct io_timeout, list);
98 		list_del_init(&timeout->list);
99 		req = cmd_to_io_kiocb(timeout);
100 		if (err)
101 			req_set_fail(req);
102 		io_req_queue_tw_complete(req, err);
103 	}
104 
105 	return true;
106 }
107 
108 static void io_kill_timeout(struct io_kiocb *req, struct list_head *list)
109 	__must_hold(&req->ctx->timeout_lock)
110 {
111 	struct io_timeout_data *io = req->async_data;
112 
113 	if (hrtimer_try_to_cancel(&io->timer) != -1) {
114 		struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
115 
116 		atomic_set(&req->ctx->cq_timeouts,
117 			atomic_read(&req->ctx->cq_timeouts) + 1);
118 		list_move_tail(&timeout->list, list);
119 	}
120 }
121 
122 __cold void io_flush_timeouts(struct io_ring_ctx *ctx)
123 {
124 	struct io_timeout *timeout, *tmp;
125 	LIST_HEAD(list);
126 	u32 seq;
127 
128 	raw_spin_lock_irq(&ctx->timeout_lock);
129 	seq = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts);
130 
131 	list_for_each_entry_safe(timeout, tmp, &ctx->timeout_list, list) {
132 		struct io_kiocb *req = cmd_to_io_kiocb(timeout);
133 		u32 events_needed, events_got;
134 
135 		if (io_is_timeout_noseq(req))
136 			break;
137 
138 		/*
139 		 * Since seq can easily wrap around over time, subtract
140 		 * the last seq at which timeouts were flushed before comparing.
141 		 * Assuming not more than 2^31-1 events have happened since,
142 		 * these subtractions won't have wrapped, so we can check if
143 		 * target is in [last_seq, current_seq] by comparing the two.
144 		 */
145 		events_needed = timeout->target_seq - ctx->cq_last_tm_flush;
146 		events_got = seq - ctx->cq_last_tm_flush;
147 		if (events_got < events_needed)
148 			break;
149 
150 		io_kill_timeout(req, &list);
151 	}
152 	ctx->cq_last_tm_flush = seq;
153 	raw_spin_unlock_irq(&ctx->timeout_lock);
154 	io_flush_killed_timeouts(&list, 0);
155 }
156 
157 static void io_req_tw_fail_links(struct io_kiocb *link, struct io_tw_state *ts)
158 {
159 	io_tw_lock(link->ctx, ts);
160 	while (link) {
161 		struct io_kiocb *nxt = link->link;
162 		long res = -ECANCELED;
163 
164 		if (link->flags & REQ_F_FAIL)
165 			res = link->cqe.res;
166 		link->link = NULL;
167 		io_req_set_res(link, res, 0);
168 		io_req_task_complete(link, ts);
169 		link = nxt;
170 	}
171 }
172 
173 static void io_fail_links(struct io_kiocb *req)
174 	__must_hold(&req->ctx->completion_lock)
175 {
176 	struct io_kiocb *link = req->link;
177 	bool ignore_cqes = req->flags & REQ_F_SKIP_LINK_CQES;
178 
179 	if (!link)
180 		return;
181 
182 	while (link) {
183 		if (ignore_cqes)
184 			link->flags |= REQ_F_CQE_SKIP;
185 		else
186 			link->flags &= ~REQ_F_CQE_SKIP;
187 		trace_io_uring_fail_link(req, link);
188 		link = link->link;
189 	}
190 
191 	link = req->link;
192 	link->io_task_work.func = io_req_tw_fail_links;
193 	io_req_task_work_add(link);
194 	req->link = NULL;
195 }
196 
197 static inline void io_remove_next_linked(struct io_kiocb *req)
198 {
199 	struct io_kiocb *nxt = req->link;
200 
201 	req->link = nxt->link;
202 	nxt->link = NULL;
203 }
204 
205 void io_disarm_next(struct io_kiocb *req)
206 	__must_hold(&req->ctx->completion_lock)
207 {
208 	struct io_kiocb *link = NULL;
209 
210 	if (req->flags & REQ_F_ARM_LTIMEOUT) {
211 		link = req->link;
212 		req->flags &= ~REQ_F_ARM_LTIMEOUT;
213 		if (link && link->opcode == IORING_OP_LINK_TIMEOUT) {
214 			io_remove_next_linked(req);
215 			io_req_queue_tw_complete(link, -ECANCELED);
216 		}
217 	} else if (req->flags & REQ_F_LINK_TIMEOUT) {
218 		struct io_ring_ctx *ctx = req->ctx;
219 
220 		raw_spin_lock_irq(&ctx->timeout_lock);
221 		link = io_disarm_linked_timeout(req);
222 		raw_spin_unlock_irq(&ctx->timeout_lock);
223 		if (link)
224 			io_req_queue_tw_complete(link, -ECANCELED);
225 	}
226 	if (unlikely((req->flags & REQ_F_FAIL) &&
227 		     !(req->flags & REQ_F_HARDLINK)))
228 		io_fail_links(req);
229 }
230 
231 struct io_kiocb *__io_disarm_linked_timeout(struct io_kiocb *req,
232 					    struct io_kiocb *link)
233 	__must_hold(&req->ctx->completion_lock)
234 	__must_hold(&req->ctx->timeout_lock)
235 {
236 	struct io_timeout_data *io = link->async_data;
237 	struct io_timeout *timeout = io_kiocb_to_cmd(link, struct io_timeout);
238 
239 	io_remove_next_linked(req);
240 	timeout->head = NULL;
241 	if (hrtimer_try_to_cancel(&io->timer) != -1) {
242 		list_del(&timeout->list);
243 		return link;
244 	}
245 
246 	return NULL;
247 }
248 
249 static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
250 {
251 	struct io_timeout_data *data = container_of(timer,
252 						struct io_timeout_data, timer);
253 	struct io_kiocb *req = data->req;
254 	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
255 	struct io_ring_ctx *ctx = req->ctx;
256 	unsigned long flags;
257 
258 	raw_spin_lock_irqsave(&ctx->timeout_lock, flags);
259 	list_del_init(&timeout->list);
260 	atomic_set(&req->ctx->cq_timeouts,
261 		atomic_read(&req->ctx->cq_timeouts) + 1);
262 	raw_spin_unlock_irqrestore(&ctx->timeout_lock, flags);
263 
264 	if (!(data->flags & IORING_TIMEOUT_ETIME_SUCCESS))
265 		req_set_fail(req);
266 
267 	io_req_set_res(req, -ETIME, 0);
268 	req->io_task_work.func = io_timeout_complete;
269 	io_req_task_work_add(req);
270 	return HRTIMER_NORESTART;
271 }
272 
273 static struct io_kiocb *io_timeout_extract(struct io_ring_ctx *ctx,
274 					   struct io_cancel_data *cd)
275 	__must_hold(&ctx->timeout_lock)
276 {
277 	struct io_timeout *timeout;
278 	struct io_timeout_data *io;
279 	struct io_kiocb *req = NULL;
280 
281 	list_for_each_entry(timeout, &ctx->timeout_list, list) {
282 		struct io_kiocb *tmp = cmd_to_io_kiocb(timeout);
283 
284 		if (io_cancel_req_match(tmp, cd)) {
285 			req = tmp;
286 			break;
287 		}
288 	}
289 	if (!req)
290 		return ERR_PTR(-ENOENT);
291 
292 	io = req->async_data;
293 	if (hrtimer_try_to_cancel(&io->timer) == -1)
294 		return ERR_PTR(-EALREADY);
295 	timeout = io_kiocb_to_cmd(req, struct io_timeout);
296 	list_del_init(&timeout->list);
297 	return req;
298 }
299 
300 int io_timeout_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd)
301 	__must_hold(&ctx->completion_lock)
302 {
303 	struct io_kiocb *req;
304 
305 	raw_spin_lock_irq(&ctx->timeout_lock);
306 	req = io_timeout_extract(ctx, cd);
307 	raw_spin_unlock_irq(&ctx->timeout_lock);
308 
309 	if (IS_ERR(req))
310 		return PTR_ERR(req);
311 	io_req_task_queue_fail(req, -ECANCELED);
312 	return 0;
313 }
314 
315 static void io_req_task_link_timeout(struct io_kiocb *req, struct io_tw_state *ts)
316 {
317 	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
318 	struct io_kiocb *prev = timeout->prev;
319 	int ret;
320 
321 	if (prev) {
322 		if (!io_should_terminate_tw()) {
323 			struct io_cancel_data cd = {
324 				.ctx		= req->ctx,
325 				.data		= prev->cqe.user_data,
326 			};
327 
328 			ret = io_try_cancel(req->tctx, &cd, 0);
329 		} else {
330 			ret = -ECANCELED;
331 		}
332 		io_req_set_res(req, ret ?: -ETIME, 0);
333 		io_req_task_complete(req, ts);
334 		io_put_req(prev);
335 	} else {
336 		io_req_set_res(req, -ETIME, 0);
337 		io_req_task_complete(req, ts);
338 	}
339 }
340 
341 static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer)
342 {
343 	struct io_timeout_data *data = container_of(timer,
344 						struct io_timeout_data, timer);
345 	struct io_kiocb *prev, *req = data->req;
346 	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
347 	struct io_ring_ctx *ctx = req->ctx;
348 	unsigned long flags;
349 
350 	raw_spin_lock_irqsave(&ctx->timeout_lock, flags);
351 	prev = timeout->head;
352 	timeout->head = NULL;
353 
354 	/*
355 	 * We don't expect the list to be empty, that will only happen if we
356 	 * race with the completion of the linked work.
357 	 */
358 	if (prev) {
359 		io_remove_next_linked(prev);
360 		if (!req_ref_inc_not_zero(prev))
361 			prev = NULL;
362 	}
363 	list_del(&timeout->list);
364 	timeout->prev = prev;
365 	raw_spin_unlock_irqrestore(&ctx->timeout_lock, flags);
366 
367 	req->io_task_work.func = io_req_task_link_timeout;
368 	io_req_task_work_add(req);
369 	return HRTIMER_NORESTART;
370 }
371 
372 static clockid_t io_timeout_get_clock(struct io_timeout_data *data)
373 {
374 	switch (data->flags & IORING_TIMEOUT_CLOCK_MASK) {
375 	case IORING_TIMEOUT_BOOTTIME:
376 		return CLOCK_BOOTTIME;
377 	case IORING_TIMEOUT_REALTIME:
378 		return CLOCK_REALTIME;
379 	default:
380 		/* can't happen, vetted at prep time */
381 		WARN_ON_ONCE(1);
382 		fallthrough;
383 	case 0:
384 		return CLOCK_MONOTONIC;
385 	}
386 }
387 
388 static int io_linked_timeout_update(struct io_ring_ctx *ctx, __u64 user_data,
389 				    struct timespec64 *ts, enum hrtimer_mode mode)
390 	__must_hold(&ctx->timeout_lock)
391 {
392 	struct io_timeout_data *io;
393 	struct io_timeout *timeout;
394 	struct io_kiocb *req = NULL;
395 
396 	list_for_each_entry(timeout, &ctx->ltimeout_list, list) {
397 		struct io_kiocb *tmp = cmd_to_io_kiocb(timeout);
398 
399 		if (user_data == tmp->cqe.user_data) {
400 			req = tmp;
401 			break;
402 		}
403 	}
404 	if (!req)
405 		return -ENOENT;
406 
407 	io = req->async_data;
408 	if (hrtimer_try_to_cancel(&io->timer) == -1)
409 		return -EALREADY;
410 	hrtimer_init(&io->timer, io_timeout_get_clock(io), mode);
411 	io->timer.function = io_link_timeout_fn;
412 	hrtimer_start(&io->timer, timespec64_to_ktime(*ts), mode);
413 	return 0;
414 }
415 
416 static int io_timeout_update(struct io_ring_ctx *ctx, __u64 user_data,
417 			     struct timespec64 *ts, enum hrtimer_mode mode)
418 	__must_hold(&ctx->timeout_lock)
419 {
420 	struct io_cancel_data cd = { .ctx = ctx, .data = user_data, };
421 	struct io_kiocb *req = io_timeout_extract(ctx, &cd);
422 	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
423 	struct io_timeout_data *data;
424 
425 	if (IS_ERR(req))
426 		return PTR_ERR(req);
427 
428 	timeout->off = 0; /* noseq */
429 	data = req->async_data;
430 	list_add_tail(&timeout->list, &ctx->timeout_list);
431 	hrtimer_init(&data->timer, io_timeout_get_clock(data), mode);
432 	data->timer.function = io_timeout_fn;
433 	hrtimer_start(&data->timer, timespec64_to_ktime(*ts), mode);
434 	return 0;
435 }
436 
437 int io_timeout_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
438 {
439 	struct io_timeout_rem *tr = io_kiocb_to_cmd(req, struct io_timeout_rem);
440 
441 	if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
442 		return -EINVAL;
443 	if (sqe->buf_index || sqe->len || sqe->splice_fd_in)
444 		return -EINVAL;
445 
446 	tr->ltimeout = false;
447 	tr->addr = READ_ONCE(sqe->addr);
448 	tr->flags = READ_ONCE(sqe->timeout_flags);
449 	if (tr->flags & IORING_TIMEOUT_UPDATE_MASK) {
450 		if (hweight32(tr->flags & IORING_TIMEOUT_CLOCK_MASK) > 1)
451 			return -EINVAL;
452 		if (tr->flags & IORING_LINK_TIMEOUT_UPDATE)
453 			tr->ltimeout = true;
454 		if (tr->flags & ~(IORING_TIMEOUT_UPDATE_MASK|IORING_TIMEOUT_ABS))
455 			return -EINVAL;
456 		if (get_timespec64(&tr->ts, u64_to_user_ptr(sqe->addr2)))
457 			return -EFAULT;
458 		if (tr->ts.tv_sec < 0 || tr->ts.tv_nsec < 0)
459 			return -EINVAL;
460 	} else if (tr->flags) {
461 		/* timeout removal doesn't support flags */
462 		return -EINVAL;
463 	}
464 
465 	return 0;
466 }
467 
468 static inline enum hrtimer_mode io_translate_timeout_mode(unsigned int flags)
469 {
470 	return (flags & IORING_TIMEOUT_ABS) ? HRTIMER_MODE_ABS
471 					    : HRTIMER_MODE_REL;
472 }
473 
474 /*
475  * Remove or update an existing timeout command
476  */
477 int io_timeout_remove(struct io_kiocb *req, unsigned int issue_flags)
478 {
479 	struct io_timeout_rem *tr = io_kiocb_to_cmd(req, struct io_timeout_rem);
480 	struct io_ring_ctx *ctx = req->ctx;
481 	int ret;
482 
483 	if (!(tr->flags & IORING_TIMEOUT_UPDATE)) {
484 		struct io_cancel_data cd = { .ctx = ctx, .data = tr->addr, };
485 
486 		spin_lock(&ctx->completion_lock);
487 		ret = io_timeout_cancel(ctx, &cd);
488 		spin_unlock(&ctx->completion_lock);
489 	} else {
490 		enum hrtimer_mode mode = io_translate_timeout_mode(tr->flags);
491 
492 		raw_spin_lock_irq(&ctx->timeout_lock);
493 		if (tr->ltimeout)
494 			ret = io_linked_timeout_update(ctx, tr->addr, &tr->ts, mode);
495 		else
496 			ret = io_timeout_update(ctx, tr->addr, &tr->ts, mode);
497 		raw_spin_unlock_irq(&ctx->timeout_lock);
498 	}
499 
500 	if (ret < 0)
501 		req_set_fail(req);
502 	io_req_set_res(req, ret, 0);
503 	return IOU_OK;
504 }
505 
506 static int __io_timeout_prep(struct io_kiocb *req,
507 			     const struct io_uring_sqe *sqe,
508 			     bool is_timeout_link)
509 {
510 	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
511 	struct io_timeout_data *data;
512 	unsigned flags;
513 	u32 off = READ_ONCE(sqe->off);
514 
515 	if (sqe->buf_index || sqe->len != 1 || sqe->splice_fd_in)
516 		return -EINVAL;
517 	if (off && is_timeout_link)
518 		return -EINVAL;
519 	flags = READ_ONCE(sqe->timeout_flags);
520 	if (flags & ~(IORING_TIMEOUT_ABS | IORING_TIMEOUT_CLOCK_MASK |
521 		      IORING_TIMEOUT_ETIME_SUCCESS |
522 		      IORING_TIMEOUT_MULTISHOT))
523 		return -EINVAL;
524 	/* more than one clock specified is invalid, obviously */
525 	if (hweight32(flags & IORING_TIMEOUT_CLOCK_MASK) > 1)
526 		return -EINVAL;
527 	/* multishot requests only make sense with rel values */
528 	if (!(~flags & (IORING_TIMEOUT_MULTISHOT | IORING_TIMEOUT_ABS)))
529 		return -EINVAL;
530 
531 	INIT_LIST_HEAD(&timeout->list);
532 	timeout->off = off;
533 	if (unlikely(off && !req->ctx->off_timeout_used))
534 		req->ctx->off_timeout_used = true;
535 	/*
536 	 * for multishot reqs w/ fixed nr of repeats, repeats tracks the
537 	 * remaining nr
538 	 */
539 	timeout->repeats = 0;
540 	if ((flags & IORING_TIMEOUT_MULTISHOT) && off > 0)
541 		timeout->repeats = off;
542 
543 	if (WARN_ON_ONCE(req_has_async_data(req)))
544 		return -EFAULT;
545 	if (io_alloc_async_data(req))
546 		return -ENOMEM;
547 
548 	data = req->async_data;
549 	data->req = req;
550 	data->flags = flags;
551 
552 	if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr)))
553 		return -EFAULT;
554 
555 	if (data->ts.tv_sec < 0 || data->ts.tv_nsec < 0)
556 		return -EINVAL;
557 
558 	data->mode = io_translate_timeout_mode(flags);
559 	hrtimer_init(&data->timer, io_timeout_get_clock(data), data->mode);
560 
561 	if (is_timeout_link) {
562 		struct io_submit_link *link = &req->ctx->submit_state.link;
563 
564 		if (!link->head)
565 			return -EINVAL;
566 		if (link->last->opcode == IORING_OP_LINK_TIMEOUT)
567 			return -EINVAL;
568 		timeout->head = link->last;
569 		link->last->flags |= REQ_F_ARM_LTIMEOUT;
570 	}
571 	return 0;
572 }
573 
574 int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
575 {
576 	return __io_timeout_prep(req, sqe, false);
577 }
578 
579 int io_link_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
580 {
581 	return __io_timeout_prep(req, sqe, true);
582 }
583 
584 int io_timeout(struct io_kiocb *req, unsigned int issue_flags)
585 {
586 	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
587 	struct io_ring_ctx *ctx = req->ctx;
588 	struct io_timeout_data *data = req->async_data;
589 	struct list_head *entry;
590 	u32 tail, off = timeout->off;
591 
592 	raw_spin_lock_irq(&ctx->timeout_lock);
593 
594 	/*
595 	 * sqe->off holds how many events that need to occur for this
596 	 * timeout event to be satisfied. If it isn't set, then this is
597 	 * a pure timeout request, sequence isn't used.
598 	 */
599 	if (io_is_timeout_noseq(req)) {
600 		entry = ctx->timeout_list.prev;
601 		goto add;
602 	}
603 
604 	tail = data_race(ctx->cached_cq_tail) - atomic_read(&ctx->cq_timeouts);
605 	timeout->target_seq = tail + off;
606 
607 	/* Update the last seq here in case io_flush_timeouts() hasn't.
608 	 * This is safe because ->completion_lock is held, and submissions
609 	 * and completions are never mixed in the same ->completion_lock section.
610 	 */
611 	ctx->cq_last_tm_flush = tail;
612 
613 	/*
614 	 * Insertion sort, ensuring the first entry in the list is always
615 	 * the one we need first.
616 	 */
617 	list_for_each_prev(entry, &ctx->timeout_list) {
618 		struct io_timeout *nextt = list_entry(entry, struct io_timeout, list);
619 		struct io_kiocb *nxt = cmd_to_io_kiocb(nextt);
620 
621 		if (io_is_timeout_noseq(nxt))
622 			continue;
623 		/* nxt.seq is behind @tail, otherwise would've been completed */
624 		if (off >= nextt->target_seq - tail)
625 			break;
626 	}
627 add:
628 	list_add(&timeout->list, entry);
629 	data->timer.function = io_timeout_fn;
630 	hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode);
631 	raw_spin_unlock_irq(&ctx->timeout_lock);
632 	return IOU_ISSUE_SKIP_COMPLETE;
633 }
634 
635 void io_queue_linked_timeout(struct io_kiocb *req)
636 {
637 	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
638 	struct io_ring_ctx *ctx = req->ctx;
639 
640 	raw_spin_lock_irq(&ctx->timeout_lock);
641 	/*
642 	 * If the back reference is NULL, then our linked request finished
643 	 * before we got a chance to setup the timer
644 	 */
645 	if (timeout->head) {
646 		struct io_timeout_data *data = req->async_data;
647 
648 		data->timer.function = io_link_timeout_fn;
649 		hrtimer_start(&data->timer, timespec64_to_ktime(data->ts),
650 				data->mode);
651 		list_add_tail(&timeout->list, &ctx->ltimeout_list);
652 	}
653 	raw_spin_unlock_irq(&ctx->timeout_lock);
654 	/* drop submission reference */
655 	io_put_req(req);
656 }
657 
658 static bool io_match_task(struct io_kiocb *head, struct io_uring_task *tctx,
659 			  bool cancel_all)
660 	__must_hold(&head->ctx->timeout_lock)
661 {
662 	struct io_kiocb *req;
663 
664 	if (tctx && head->tctx != tctx)
665 		return false;
666 	if (cancel_all)
667 		return true;
668 
669 	io_for_each_link(req, head) {
670 		if (req->flags & REQ_F_INFLIGHT)
671 			return true;
672 	}
673 	return false;
674 }
675 
676 /* Returns true if we found and killed one or more timeouts */
677 __cold bool io_kill_timeouts(struct io_ring_ctx *ctx, struct io_uring_task *tctx,
678 			     bool cancel_all)
679 {
680 	struct io_timeout *timeout, *tmp;
681 	LIST_HEAD(list);
682 
683 	/*
684 	 * completion_lock is needed for io_match_task(). Take it before
685 	 * timeout_lockfirst to keep locking ordering.
686 	 */
687 	spin_lock(&ctx->completion_lock);
688 	raw_spin_lock_irq(&ctx->timeout_lock);
689 	list_for_each_entry_safe(timeout, tmp, &ctx->timeout_list, list) {
690 		struct io_kiocb *req = cmd_to_io_kiocb(timeout);
691 
692 		if (io_match_task(req, tctx, cancel_all))
693 			io_kill_timeout(req, &list);
694 	}
695 	raw_spin_unlock_irq(&ctx->timeout_lock);
696 	spin_unlock(&ctx->completion_lock);
697 
698 	return io_flush_killed_timeouts(&list, -ECANCELED);
699 }
700