xref: /linux/io_uring/timeout.c (revision 2f804aca48322f02a8f44cca540663845ee80fb1)
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 		bool filled;
76 		filled = io_aux_cqe(ctx, ts->locked, req->cqe.user_data, -ETIME,
77 				    IORING_CQE_F_MORE, false);
78 		if (filled) {
79 			/* re-arm timer */
80 			spin_lock_irq(&ctx->timeout_lock);
81 			list_add(&timeout->list, ctx->timeout_list.prev);
82 			data->timer.function = io_timeout_fn;
83 			hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode);
84 			spin_unlock_irq(&ctx->timeout_lock);
85 			return;
86 		}
87 	}
88 
89 	io_req_task_complete(req, ts);
90 }
91 
92 static bool io_kill_timeout(struct io_kiocb *req, int status)
93 	__must_hold(&req->ctx->timeout_lock)
94 {
95 	struct io_timeout_data *io = req->async_data;
96 
97 	if (hrtimer_try_to_cancel(&io->timer) != -1) {
98 		struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
99 
100 		if (status)
101 			req_set_fail(req);
102 		atomic_set(&req->ctx->cq_timeouts,
103 			atomic_read(&req->ctx->cq_timeouts) + 1);
104 		list_del_init(&timeout->list);
105 		io_req_queue_tw_complete(req, status);
106 		return true;
107 	}
108 	return false;
109 }
110 
111 __cold void io_flush_timeouts(struct io_ring_ctx *ctx)
112 {
113 	u32 seq;
114 	struct io_timeout *timeout, *tmp;
115 
116 	spin_lock_irq(&ctx->timeout_lock);
117 	seq = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts);
118 
119 	list_for_each_entry_safe(timeout, tmp, &ctx->timeout_list, list) {
120 		struct io_kiocb *req = cmd_to_io_kiocb(timeout);
121 		u32 events_needed, events_got;
122 
123 		if (io_is_timeout_noseq(req))
124 			break;
125 
126 		/*
127 		 * Since seq can easily wrap around over time, subtract
128 		 * the last seq at which timeouts were flushed before comparing.
129 		 * Assuming not more than 2^31-1 events have happened since,
130 		 * these subtractions won't have wrapped, so we can check if
131 		 * target is in [last_seq, current_seq] by comparing the two.
132 		 */
133 		events_needed = timeout->target_seq - ctx->cq_last_tm_flush;
134 		events_got = seq - ctx->cq_last_tm_flush;
135 		if (events_got < events_needed)
136 			break;
137 
138 		io_kill_timeout(req, 0);
139 	}
140 	ctx->cq_last_tm_flush = seq;
141 	spin_unlock_irq(&ctx->timeout_lock);
142 }
143 
144 static void io_req_tw_fail_links(struct io_kiocb *link, struct io_tw_state *ts)
145 {
146 	io_tw_lock(link->ctx, ts);
147 	while (link) {
148 		struct io_kiocb *nxt = link->link;
149 		long res = -ECANCELED;
150 
151 		if (link->flags & REQ_F_FAIL)
152 			res = link->cqe.res;
153 		link->link = NULL;
154 		io_req_set_res(link, res, 0);
155 		io_req_task_complete(link, ts);
156 		link = nxt;
157 	}
158 }
159 
160 static void io_fail_links(struct io_kiocb *req)
161 	__must_hold(&req->ctx->completion_lock)
162 {
163 	struct io_kiocb *link = req->link;
164 	bool ignore_cqes = req->flags & REQ_F_SKIP_LINK_CQES;
165 
166 	if (!link)
167 		return;
168 
169 	while (link) {
170 		if (ignore_cqes)
171 			link->flags |= REQ_F_CQE_SKIP;
172 		else
173 			link->flags &= ~REQ_F_CQE_SKIP;
174 		trace_io_uring_fail_link(req, link);
175 		link = link->link;
176 	}
177 
178 	link = req->link;
179 	link->io_task_work.func = io_req_tw_fail_links;
180 	io_req_task_work_add(link);
181 	req->link = NULL;
182 }
183 
184 static inline void io_remove_next_linked(struct io_kiocb *req)
185 {
186 	struct io_kiocb *nxt = req->link;
187 
188 	req->link = nxt->link;
189 	nxt->link = NULL;
190 }
191 
192 void io_disarm_next(struct io_kiocb *req)
193 	__must_hold(&req->ctx->completion_lock)
194 {
195 	struct io_kiocb *link = NULL;
196 
197 	if (req->flags & REQ_F_ARM_LTIMEOUT) {
198 		link = req->link;
199 		req->flags &= ~REQ_F_ARM_LTIMEOUT;
200 		if (link && link->opcode == IORING_OP_LINK_TIMEOUT) {
201 			io_remove_next_linked(req);
202 			io_req_queue_tw_complete(link, -ECANCELED);
203 		}
204 	} else if (req->flags & REQ_F_LINK_TIMEOUT) {
205 		struct io_ring_ctx *ctx = req->ctx;
206 
207 		spin_lock_irq(&ctx->timeout_lock);
208 		link = io_disarm_linked_timeout(req);
209 		spin_unlock_irq(&ctx->timeout_lock);
210 		if (link)
211 			io_req_queue_tw_complete(link, -ECANCELED);
212 	}
213 	if (unlikely((req->flags & REQ_F_FAIL) &&
214 		     !(req->flags & REQ_F_HARDLINK)))
215 		io_fail_links(req);
216 }
217 
218 struct io_kiocb *__io_disarm_linked_timeout(struct io_kiocb *req,
219 					    struct io_kiocb *link)
220 	__must_hold(&req->ctx->completion_lock)
221 	__must_hold(&req->ctx->timeout_lock)
222 {
223 	struct io_timeout_data *io = link->async_data;
224 	struct io_timeout *timeout = io_kiocb_to_cmd(link, struct io_timeout);
225 
226 	io_remove_next_linked(req);
227 	timeout->head = NULL;
228 	if (hrtimer_try_to_cancel(&io->timer) != -1) {
229 		list_del(&timeout->list);
230 		return link;
231 	}
232 
233 	return NULL;
234 }
235 
236 static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
237 {
238 	struct io_timeout_data *data = container_of(timer,
239 						struct io_timeout_data, timer);
240 	struct io_kiocb *req = data->req;
241 	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
242 	struct io_ring_ctx *ctx = req->ctx;
243 	unsigned long flags;
244 
245 	spin_lock_irqsave(&ctx->timeout_lock, flags);
246 	list_del_init(&timeout->list);
247 	atomic_set(&req->ctx->cq_timeouts,
248 		atomic_read(&req->ctx->cq_timeouts) + 1);
249 	spin_unlock_irqrestore(&ctx->timeout_lock, flags);
250 
251 	if (!(data->flags & IORING_TIMEOUT_ETIME_SUCCESS))
252 		req_set_fail(req);
253 
254 	io_req_set_res(req, -ETIME, 0);
255 	req->io_task_work.func = io_timeout_complete;
256 	io_req_task_work_add(req);
257 	return HRTIMER_NORESTART;
258 }
259 
260 static struct io_kiocb *io_timeout_extract(struct io_ring_ctx *ctx,
261 					   struct io_cancel_data *cd)
262 	__must_hold(&ctx->timeout_lock)
263 {
264 	struct io_timeout *timeout;
265 	struct io_timeout_data *io;
266 	struct io_kiocb *req = NULL;
267 
268 	list_for_each_entry(timeout, &ctx->timeout_list, list) {
269 		struct io_kiocb *tmp = cmd_to_io_kiocb(timeout);
270 
271 		if (!(cd->flags & IORING_ASYNC_CANCEL_ANY) &&
272 		    cd->data != tmp->cqe.user_data)
273 			continue;
274 		if (cd->flags & (IORING_ASYNC_CANCEL_ALL|IORING_ASYNC_CANCEL_ANY)) {
275 			if (cd->seq == tmp->work.cancel_seq)
276 				continue;
277 			tmp->work.cancel_seq = cd->seq;
278 		}
279 		req = tmp;
280 		break;
281 	}
282 	if (!req)
283 		return ERR_PTR(-ENOENT);
284 
285 	io = req->async_data;
286 	if (hrtimer_try_to_cancel(&io->timer) == -1)
287 		return ERR_PTR(-EALREADY);
288 	timeout = io_kiocb_to_cmd(req, struct io_timeout);
289 	list_del_init(&timeout->list);
290 	return req;
291 }
292 
293 int io_timeout_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd)
294 	__must_hold(&ctx->completion_lock)
295 {
296 	struct io_kiocb *req;
297 
298 	spin_lock_irq(&ctx->timeout_lock);
299 	req = io_timeout_extract(ctx, cd);
300 	spin_unlock_irq(&ctx->timeout_lock);
301 
302 	if (IS_ERR(req))
303 		return PTR_ERR(req);
304 	io_req_task_queue_fail(req, -ECANCELED);
305 	return 0;
306 }
307 
308 static void io_req_task_link_timeout(struct io_kiocb *req, struct io_tw_state *ts)
309 {
310 	unsigned issue_flags = ts->locked ? 0 : IO_URING_F_UNLOCKED;
311 	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
312 	struct io_kiocb *prev = timeout->prev;
313 	int ret = -ENOENT;
314 
315 	if (prev) {
316 		if (!(req->task->flags & PF_EXITING)) {
317 			struct io_cancel_data cd = {
318 				.ctx		= req->ctx,
319 				.data		= prev->cqe.user_data,
320 			};
321 
322 			ret = io_try_cancel(req->task->io_uring, &cd, issue_flags);
323 		}
324 		io_req_set_res(req, ret ?: -ETIME, 0);
325 		io_req_task_complete(req, ts);
326 		io_put_req(prev);
327 	} else {
328 		io_req_set_res(req, -ETIME, 0);
329 		io_req_task_complete(req, ts);
330 	}
331 }
332 
333 static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer)
334 {
335 	struct io_timeout_data *data = container_of(timer,
336 						struct io_timeout_data, timer);
337 	struct io_kiocb *prev, *req = data->req;
338 	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
339 	struct io_ring_ctx *ctx = req->ctx;
340 	unsigned long flags;
341 
342 	spin_lock_irqsave(&ctx->timeout_lock, flags);
343 	prev = timeout->head;
344 	timeout->head = NULL;
345 
346 	/*
347 	 * We don't expect the list to be empty, that will only happen if we
348 	 * race with the completion of the linked work.
349 	 */
350 	if (prev) {
351 		io_remove_next_linked(prev);
352 		if (!req_ref_inc_not_zero(prev))
353 			prev = NULL;
354 	}
355 	list_del(&timeout->list);
356 	timeout->prev = prev;
357 	spin_unlock_irqrestore(&ctx->timeout_lock, flags);
358 
359 	req->io_task_work.func = io_req_task_link_timeout;
360 	io_req_task_work_add(req);
361 	return HRTIMER_NORESTART;
362 }
363 
364 static clockid_t io_timeout_get_clock(struct io_timeout_data *data)
365 {
366 	switch (data->flags & IORING_TIMEOUT_CLOCK_MASK) {
367 	case IORING_TIMEOUT_BOOTTIME:
368 		return CLOCK_BOOTTIME;
369 	case IORING_TIMEOUT_REALTIME:
370 		return CLOCK_REALTIME;
371 	default:
372 		/* can't happen, vetted at prep time */
373 		WARN_ON_ONCE(1);
374 		fallthrough;
375 	case 0:
376 		return CLOCK_MONOTONIC;
377 	}
378 }
379 
380 static int io_linked_timeout_update(struct io_ring_ctx *ctx, __u64 user_data,
381 				    struct timespec64 *ts, enum hrtimer_mode mode)
382 	__must_hold(&ctx->timeout_lock)
383 {
384 	struct io_timeout_data *io;
385 	struct io_timeout *timeout;
386 	struct io_kiocb *req = NULL;
387 
388 	list_for_each_entry(timeout, &ctx->ltimeout_list, list) {
389 		struct io_kiocb *tmp = cmd_to_io_kiocb(timeout);
390 
391 		if (user_data == tmp->cqe.user_data) {
392 			req = tmp;
393 			break;
394 		}
395 	}
396 	if (!req)
397 		return -ENOENT;
398 
399 	io = req->async_data;
400 	if (hrtimer_try_to_cancel(&io->timer) == -1)
401 		return -EALREADY;
402 	hrtimer_init(&io->timer, io_timeout_get_clock(io), mode);
403 	io->timer.function = io_link_timeout_fn;
404 	hrtimer_start(&io->timer, timespec64_to_ktime(*ts), mode);
405 	return 0;
406 }
407 
408 static int io_timeout_update(struct io_ring_ctx *ctx, __u64 user_data,
409 			     struct timespec64 *ts, enum hrtimer_mode mode)
410 	__must_hold(&ctx->timeout_lock)
411 {
412 	struct io_cancel_data cd = { .data = user_data, };
413 	struct io_kiocb *req = io_timeout_extract(ctx, &cd);
414 	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
415 	struct io_timeout_data *data;
416 
417 	if (IS_ERR(req))
418 		return PTR_ERR(req);
419 
420 	timeout->off = 0; /* noseq */
421 	data = req->async_data;
422 	list_add_tail(&timeout->list, &ctx->timeout_list);
423 	hrtimer_init(&data->timer, io_timeout_get_clock(data), mode);
424 	data->timer.function = io_timeout_fn;
425 	hrtimer_start(&data->timer, timespec64_to_ktime(*ts), mode);
426 	return 0;
427 }
428 
429 int io_timeout_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
430 {
431 	struct io_timeout_rem *tr = io_kiocb_to_cmd(req, struct io_timeout_rem);
432 
433 	if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
434 		return -EINVAL;
435 	if (sqe->buf_index || sqe->len || sqe->splice_fd_in)
436 		return -EINVAL;
437 
438 	tr->ltimeout = false;
439 	tr->addr = READ_ONCE(sqe->addr);
440 	tr->flags = READ_ONCE(sqe->timeout_flags);
441 	if (tr->flags & IORING_TIMEOUT_UPDATE_MASK) {
442 		if (hweight32(tr->flags & IORING_TIMEOUT_CLOCK_MASK) > 1)
443 			return -EINVAL;
444 		if (tr->flags & IORING_LINK_TIMEOUT_UPDATE)
445 			tr->ltimeout = true;
446 		if (tr->flags & ~(IORING_TIMEOUT_UPDATE_MASK|IORING_TIMEOUT_ABS))
447 			return -EINVAL;
448 		if (get_timespec64(&tr->ts, u64_to_user_ptr(sqe->addr2)))
449 			return -EFAULT;
450 		if (tr->ts.tv_sec < 0 || tr->ts.tv_nsec < 0)
451 			return -EINVAL;
452 	} else if (tr->flags) {
453 		/* timeout removal doesn't support flags */
454 		return -EINVAL;
455 	}
456 
457 	return 0;
458 }
459 
460 static inline enum hrtimer_mode io_translate_timeout_mode(unsigned int flags)
461 {
462 	return (flags & IORING_TIMEOUT_ABS) ? HRTIMER_MODE_ABS
463 					    : HRTIMER_MODE_REL;
464 }
465 
466 /*
467  * Remove or update an existing timeout command
468  */
469 int io_timeout_remove(struct io_kiocb *req, unsigned int issue_flags)
470 {
471 	struct io_timeout_rem *tr = io_kiocb_to_cmd(req, struct io_timeout_rem);
472 	struct io_ring_ctx *ctx = req->ctx;
473 	int ret;
474 
475 	if (!(tr->flags & IORING_TIMEOUT_UPDATE)) {
476 		struct io_cancel_data cd = { .data = tr->addr, };
477 
478 		spin_lock(&ctx->completion_lock);
479 		ret = io_timeout_cancel(ctx, &cd);
480 		spin_unlock(&ctx->completion_lock);
481 	} else {
482 		enum hrtimer_mode mode = io_translate_timeout_mode(tr->flags);
483 
484 		spin_lock_irq(&ctx->timeout_lock);
485 		if (tr->ltimeout)
486 			ret = io_linked_timeout_update(ctx, tr->addr, &tr->ts, mode);
487 		else
488 			ret = io_timeout_update(ctx, tr->addr, &tr->ts, mode);
489 		spin_unlock_irq(&ctx->timeout_lock);
490 	}
491 
492 	if (ret < 0)
493 		req_set_fail(req);
494 	io_req_set_res(req, ret, 0);
495 	return IOU_OK;
496 }
497 
498 static int __io_timeout_prep(struct io_kiocb *req,
499 			     const struct io_uring_sqe *sqe,
500 			     bool is_timeout_link)
501 {
502 	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
503 	struct io_timeout_data *data;
504 	unsigned flags;
505 	u32 off = READ_ONCE(sqe->off);
506 
507 	if (sqe->buf_index || sqe->len != 1 || sqe->splice_fd_in)
508 		return -EINVAL;
509 	if (off && is_timeout_link)
510 		return -EINVAL;
511 	flags = READ_ONCE(sqe->timeout_flags);
512 	if (flags & ~(IORING_TIMEOUT_ABS | IORING_TIMEOUT_CLOCK_MASK |
513 		      IORING_TIMEOUT_ETIME_SUCCESS |
514 		      IORING_TIMEOUT_MULTISHOT))
515 		return -EINVAL;
516 	/* more than one clock specified is invalid, obviously */
517 	if (hweight32(flags & IORING_TIMEOUT_CLOCK_MASK) > 1)
518 		return -EINVAL;
519 	/* multishot requests only make sense with rel values */
520 	if (!(~flags & (IORING_TIMEOUT_MULTISHOT | IORING_TIMEOUT_ABS)))
521 		return -EINVAL;
522 
523 	INIT_LIST_HEAD(&timeout->list);
524 	timeout->off = off;
525 	if (unlikely(off && !req->ctx->off_timeout_used))
526 		req->ctx->off_timeout_used = true;
527 	/*
528 	 * for multishot reqs w/ fixed nr of repeats, repeats tracks the
529 	 * remaining nr
530 	 */
531 	timeout->repeats = 0;
532 	if ((flags & IORING_TIMEOUT_MULTISHOT) && off > 0)
533 		timeout->repeats = off;
534 
535 	if (WARN_ON_ONCE(req_has_async_data(req)))
536 		return -EFAULT;
537 	if (io_alloc_async_data(req))
538 		return -ENOMEM;
539 
540 	data = req->async_data;
541 	data->req = req;
542 	data->flags = flags;
543 
544 	if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr)))
545 		return -EFAULT;
546 
547 	if (data->ts.tv_sec < 0 || data->ts.tv_nsec < 0)
548 		return -EINVAL;
549 
550 	INIT_LIST_HEAD(&timeout->list);
551 	data->mode = io_translate_timeout_mode(flags);
552 	hrtimer_init(&data->timer, io_timeout_get_clock(data), data->mode);
553 
554 	if (is_timeout_link) {
555 		struct io_submit_link *link = &req->ctx->submit_state.link;
556 
557 		if (!link->head)
558 			return -EINVAL;
559 		if (link->last->opcode == IORING_OP_LINK_TIMEOUT)
560 			return -EINVAL;
561 		timeout->head = link->last;
562 		link->last->flags |= REQ_F_ARM_LTIMEOUT;
563 	}
564 	return 0;
565 }
566 
567 int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
568 {
569 	return __io_timeout_prep(req, sqe, false);
570 }
571 
572 int io_link_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
573 {
574 	return __io_timeout_prep(req, sqe, true);
575 }
576 
577 int io_timeout(struct io_kiocb *req, unsigned int issue_flags)
578 {
579 	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
580 	struct io_ring_ctx *ctx = req->ctx;
581 	struct io_timeout_data *data = req->async_data;
582 	struct list_head *entry;
583 	u32 tail, off = timeout->off;
584 
585 	spin_lock_irq(&ctx->timeout_lock);
586 
587 	/*
588 	 * sqe->off holds how many events that need to occur for this
589 	 * timeout event to be satisfied. If it isn't set, then this is
590 	 * a pure timeout request, sequence isn't used.
591 	 */
592 	if (io_is_timeout_noseq(req)) {
593 		entry = ctx->timeout_list.prev;
594 		goto add;
595 	}
596 
597 	tail = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts);
598 	timeout->target_seq = tail + off;
599 
600 	/* Update the last seq here in case io_flush_timeouts() hasn't.
601 	 * This is safe because ->completion_lock is held, and submissions
602 	 * and completions are never mixed in the same ->completion_lock section.
603 	 */
604 	ctx->cq_last_tm_flush = tail;
605 
606 	/*
607 	 * Insertion sort, ensuring the first entry in the list is always
608 	 * the one we need first.
609 	 */
610 	list_for_each_prev(entry, &ctx->timeout_list) {
611 		struct io_timeout *nextt = list_entry(entry, struct io_timeout, list);
612 		struct io_kiocb *nxt = cmd_to_io_kiocb(nextt);
613 
614 		if (io_is_timeout_noseq(nxt))
615 			continue;
616 		/* nxt.seq is behind @tail, otherwise would've been completed */
617 		if (off >= nextt->target_seq - tail)
618 			break;
619 	}
620 add:
621 	list_add(&timeout->list, entry);
622 	data->timer.function = io_timeout_fn;
623 	hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode);
624 	spin_unlock_irq(&ctx->timeout_lock);
625 	return IOU_ISSUE_SKIP_COMPLETE;
626 }
627 
628 void io_queue_linked_timeout(struct io_kiocb *req)
629 {
630 	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
631 	struct io_ring_ctx *ctx = req->ctx;
632 
633 	spin_lock_irq(&ctx->timeout_lock);
634 	/*
635 	 * If the back reference is NULL, then our linked request finished
636 	 * before we got a chance to setup the timer
637 	 */
638 	if (timeout->head) {
639 		struct io_timeout_data *data = req->async_data;
640 
641 		data->timer.function = io_link_timeout_fn;
642 		hrtimer_start(&data->timer, timespec64_to_ktime(data->ts),
643 				data->mode);
644 		list_add_tail(&timeout->list, &ctx->ltimeout_list);
645 	}
646 	spin_unlock_irq(&ctx->timeout_lock);
647 	/* drop submission reference */
648 	io_put_req(req);
649 }
650 
651 static bool io_match_task(struct io_kiocb *head, struct task_struct *task,
652 			  bool cancel_all)
653 	__must_hold(&req->ctx->timeout_lock)
654 {
655 	struct io_kiocb *req;
656 
657 	if (task && head->task != task)
658 		return false;
659 	if (cancel_all)
660 		return true;
661 
662 	io_for_each_link(req, head) {
663 		if (req->flags & REQ_F_INFLIGHT)
664 			return true;
665 	}
666 	return false;
667 }
668 
669 /* Returns true if we found and killed one or more timeouts */
670 __cold bool io_kill_timeouts(struct io_ring_ctx *ctx, struct task_struct *tsk,
671 			     bool cancel_all)
672 {
673 	struct io_timeout *timeout, *tmp;
674 	int canceled = 0;
675 
676 	/*
677 	 * completion_lock is needed for io_match_task(). Take it before
678 	 * timeout_lockfirst to keep locking ordering.
679 	 */
680 	spin_lock(&ctx->completion_lock);
681 	spin_lock_irq(&ctx->timeout_lock);
682 	list_for_each_entry_safe(timeout, tmp, &ctx->timeout_list, list) {
683 		struct io_kiocb *req = cmd_to_io_kiocb(timeout);
684 
685 		if (io_match_task(req, tsk, cancel_all) &&
686 		    io_kill_timeout(req, -ECANCELED))
687 			canceled++;
688 	}
689 	spin_unlock_irq(&ctx->timeout_lock);
690 	spin_unlock(&ctx->completion_lock);
691 	return canceled != 0;
692 }
693