1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/errno.h>
5 #include <linux/file.h>
7 #include <linux/slab.h>
8 #include <linux/poll.h>
9 #include <linux/hashtable.h>
10 #include <linux/io_uring.h>
12 #include <trace/events/io_uring.h>
14 #include <uapi/linux/io_uring.h>
23 struct io_poll_update {
29 bool update_user_data;
32 struct io_poll_table {
33 struct poll_table_struct pt;
38 /* output value, set only if arm poll returns >0 */
42 #define IO_POLL_CANCEL_FLAG BIT(31)
43 #define IO_POLL_RETRY_FLAG BIT(30)
44 #define IO_POLL_REF_MASK GENMASK(29, 0)
47 * We usually have 1-2 refs taken, 128 is more than enough and we want to
48 * maximise the margin between this amount and the moment when it overflows.
50 #define IO_POLL_REF_BIAS 128
52 #define IO_WQE_F_DOUBLE 1
54 static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
57 static inline struct io_kiocb *wqe_to_req(struct wait_queue_entry *wqe)
59 unsigned long priv = (unsigned long)wqe->private;
61 return (struct io_kiocb *)(priv & ~IO_WQE_F_DOUBLE);
64 static inline bool wqe_is_double(struct wait_queue_entry *wqe)
66 unsigned long priv = (unsigned long)wqe->private;
68 return priv & IO_WQE_F_DOUBLE;
71 static bool io_poll_get_ownership_slowpath(struct io_kiocb *req)
76 * poll_refs are already elevated and we don't have much hope for
77 * grabbing the ownership. Instead of incrementing set a retry flag
78 * to notify the loop that there might have been some change.
80 v = atomic_fetch_or(IO_POLL_RETRY_FLAG, &req->poll_refs);
81 if (v & IO_POLL_REF_MASK)
83 return !(atomic_fetch_inc(&req->poll_refs) & IO_POLL_REF_MASK);
87 * If refs part of ->poll_refs (see IO_POLL_REF_MASK) is 0, it's free. We can
88 * bump it and acquire ownership. It's disallowed to modify requests while not
89 * owning it, that prevents from races for enqueueing task_work's and b/w
90 * arming poll and wakeups.
92 static inline bool io_poll_get_ownership(struct io_kiocb *req)
94 if (unlikely(atomic_read(&req->poll_refs) >= IO_POLL_REF_BIAS))
95 return io_poll_get_ownership_slowpath(req);
96 return !(atomic_fetch_inc(&req->poll_refs) & IO_POLL_REF_MASK);
99 static void io_poll_mark_cancelled(struct io_kiocb *req)
101 atomic_or(IO_POLL_CANCEL_FLAG, &req->poll_refs);
104 static struct io_poll *io_poll_get_double(struct io_kiocb *req)
106 /* pure poll stashes this in ->async_data, poll driven retry elsewhere */
107 if (req->opcode == IORING_OP_POLL_ADD)
108 return req->async_data;
109 return req->apoll->double_poll;
112 static struct io_poll *io_poll_get_single(struct io_kiocb *req)
114 if (req->opcode == IORING_OP_POLL_ADD)
115 return io_kiocb_to_cmd(req, struct io_poll);
116 return &req->apoll->poll;
119 static void io_poll_req_insert(struct io_kiocb *req)
121 struct io_hash_table *table = &req->ctx->cancel_table;
122 u32 index = hash_long(req->cqe.user_data, table->hash_bits);
123 struct io_hash_bucket *hb = &table->hbs[index];
125 spin_lock(&hb->lock);
126 hlist_add_head(&req->hash_node, &hb->list);
127 spin_unlock(&hb->lock);
130 static void io_poll_req_delete(struct io_kiocb *req, struct io_ring_ctx *ctx)
132 struct io_hash_table *table = &req->ctx->cancel_table;
133 u32 index = hash_long(req->cqe.user_data, table->hash_bits);
134 spinlock_t *lock = &table->hbs[index].lock;
137 hash_del(&req->hash_node);
141 static void io_poll_req_insert_locked(struct io_kiocb *req)
143 struct io_hash_table *table = &req->ctx->cancel_table_locked;
144 u32 index = hash_long(req->cqe.user_data, table->hash_bits);
146 lockdep_assert_held(&req->ctx->uring_lock);
148 hlist_add_head(&req->hash_node, &table->hbs[index].list);
151 static void io_poll_tw_hash_eject(struct io_kiocb *req, struct io_tw_state *ts)
153 struct io_ring_ctx *ctx = req->ctx;
155 if (req->flags & REQ_F_HASH_LOCKED) {
157 * ->cancel_table_locked is protected by ->uring_lock in
158 * contrast to per bucket spinlocks. Likely, tctx_task_work()
159 * already grabbed the mutex for us, but there is a chance it
163 hash_del(&req->hash_node);
164 req->flags &= ~REQ_F_HASH_LOCKED;
166 io_poll_req_delete(req, ctx);
170 static void io_init_poll_iocb(struct io_poll *poll, __poll_t events)
173 #define IO_POLL_UNMASK (EPOLLERR|EPOLLHUP|EPOLLNVAL|EPOLLRDHUP)
174 /* mask in events that we always want/need */
175 poll->events = events | IO_POLL_UNMASK;
176 INIT_LIST_HEAD(&poll->wait.entry);
177 init_waitqueue_func_entry(&poll->wait, io_poll_wake);
180 static inline void io_poll_remove_entry(struct io_poll *poll)
182 struct wait_queue_head *head = smp_load_acquire(&poll->head);
185 spin_lock_irq(&head->lock);
186 list_del_init(&poll->wait.entry);
188 spin_unlock_irq(&head->lock);
192 static void io_poll_remove_entries(struct io_kiocb *req)
195 * Nothing to do if neither of those flags are set. Avoid dipping
196 * into the poll/apoll/double cachelines if we can.
198 if (!(req->flags & (REQ_F_SINGLE_POLL | REQ_F_DOUBLE_POLL)))
202 * While we hold the waitqueue lock and the waitqueue is nonempty,
203 * wake_up_pollfree() will wait for us. However, taking the waitqueue
204 * lock in the first place can race with the waitqueue being freed.
206 * We solve this as eventpoll does: by taking advantage of the fact that
207 * all users of wake_up_pollfree() will RCU-delay the actual free. If
208 * we enter rcu_read_lock() and see that the pointer to the queue is
209 * non-NULL, we can then lock it without the memory being freed out from
212 * Keep holding rcu_read_lock() as long as we hold the queue lock, in
213 * case the caller deletes the entry from the queue, leaving it empty.
214 * In that case, only RCU prevents the queue memory from being freed.
217 if (req->flags & REQ_F_SINGLE_POLL)
218 io_poll_remove_entry(io_poll_get_single(req));
219 if (req->flags & REQ_F_DOUBLE_POLL)
220 io_poll_remove_entry(io_poll_get_double(req));
226 IOU_POLL_NO_ACTION = 1,
227 IOU_POLL_REMOVE_POLL_USE_RES = 2,
228 IOU_POLL_REISSUE = 3,
229 IOU_POLL_REQUEUE = 4,
232 static void __io_poll_execute(struct io_kiocb *req, int mask)
236 io_req_set_res(req, mask, 0);
237 req->io_task_work.func = io_poll_task_func;
239 trace_io_uring_task_add(req, mask);
241 if (!(req->flags & REQ_F_POLL_NO_LAZY))
242 flags = IOU_F_TWQ_LAZY_WAKE;
243 __io_req_task_work_add(req, flags);
246 static inline void io_poll_execute(struct io_kiocb *req, int res)
248 if (io_poll_get_ownership(req))
249 __io_poll_execute(req, res);
253 * All poll tw should go through this. Checks for poll events, manages
254 * references, does rewait, etc.
256 * Returns a negative error on failure. IOU_POLL_NO_ACTION when no action
257 * require, which is either spurious wakeup or multishot CQE is served.
258 * IOU_POLL_DONE when it's done with the request, then the mask is stored in
259 * req->cqe.res. IOU_POLL_REMOVE_POLL_USE_RES indicates to remove multishot
260 * poll and that the result is stored in req->cqe.
262 static int io_poll_check_events(struct io_kiocb *req, struct io_tw_state *ts)
266 /* req->task == current here, checking PF_EXITING is safe */
267 if (unlikely(req->task->flags & PF_EXITING))
271 v = atomic_read(&req->poll_refs);
273 if (unlikely(v != 1)) {
274 /* tw should be the owner and so have some refs */
275 if (WARN_ON_ONCE(!(v & IO_POLL_REF_MASK)))
276 return IOU_POLL_NO_ACTION;
277 if (v & IO_POLL_CANCEL_FLAG)
280 * cqe.res contains only events of the first wake up
281 * and all others are to be lost. Redo vfs_poll() to get
284 if ((v & IO_POLL_REF_MASK) != 1)
287 if (v & IO_POLL_RETRY_FLAG) {
290 * We won't find new events that came in between
291 * vfs_poll and the ref put unless we clear the
294 atomic_andnot(IO_POLL_RETRY_FLAG, &req->poll_refs);
295 v &= ~IO_POLL_RETRY_FLAG;
299 /* the mask was stashed in __io_poll_execute */
301 struct poll_table_struct pt = { ._key = req->apoll_events };
302 req->cqe.res = vfs_poll(req->file, &pt) & req->apoll_events;
304 * We got woken with a mask, but someone else got to
305 * it first. The above vfs_poll() doesn't add us back
306 * to the waitqueue, so if we get nothing back, we
307 * should be safe and attempt a reissue.
309 if (unlikely(!req->cqe.res)) {
310 /* Multishot armed need not reissue */
311 if (!(req->apoll_events & EPOLLONESHOT))
313 return IOU_POLL_REISSUE;
316 if (req->apoll_events & EPOLLONESHOT)
317 return IOU_POLL_DONE;
319 /* multishot, just fill a CQE and proceed */
320 if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
321 __poll_t mask = mangle_poll(req->cqe.res &
324 if (!io_fill_cqe_req_aux(req, ts->locked, mask,
325 IORING_CQE_F_MORE)) {
326 io_req_set_res(req, mask, 0);
327 return IOU_POLL_REMOVE_POLL_USE_RES;
330 int ret = io_poll_issue(req, ts);
331 if (ret == IOU_STOP_MULTISHOT)
332 return IOU_POLL_REMOVE_POLL_USE_RES;
333 else if (ret == IOU_REQUEUE)
334 return IOU_POLL_REQUEUE;
339 /* force the next iteration to vfs_poll() */
343 * Release all references, retry if someone tried to restart
344 * task_work while we were executing it.
346 } while (atomic_sub_return(v & IO_POLL_REF_MASK, &req->poll_refs) &
349 return IOU_POLL_NO_ACTION;
352 void io_poll_task_func(struct io_kiocb *req, struct io_tw_state *ts)
356 ret = io_poll_check_events(req, ts);
357 if (ret == IOU_POLL_NO_ACTION) {
359 } else if (ret == IOU_POLL_REQUEUE) {
360 __io_poll_execute(req, 0);
363 io_poll_remove_entries(req);
364 io_poll_tw_hash_eject(req, ts);
366 if (req->opcode == IORING_OP_POLL_ADD) {
367 if (ret == IOU_POLL_DONE) {
368 struct io_poll *poll;
370 poll = io_kiocb_to_cmd(req, struct io_poll);
371 req->cqe.res = mangle_poll(req->cqe.res & poll->events);
372 } else if (ret == IOU_POLL_REISSUE) {
373 io_req_task_submit(req, ts);
375 } else if (ret != IOU_POLL_REMOVE_POLL_USE_RES) {
380 io_req_set_res(req, req->cqe.res, 0);
381 io_req_task_complete(req, ts);
383 io_tw_lock(req->ctx, ts);
385 if (ret == IOU_POLL_REMOVE_POLL_USE_RES)
386 io_req_task_complete(req, ts);
387 else if (ret == IOU_POLL_DONE || ret == IOU_POLL_REISSUE)
388 io_req_task_submit(req, ts);
390 io_req_defer_failed(req, ret);
394 static void io_poll_cancel_req(struct io_kiocb *req)
396 io_poll_mark_cancelled(req);
397 /* kick tw, which should complete the request */
398 io_poll_execute(req, 0);
401 #define IO_ASYNC_POLL_COMMON (EPOLLONESHOT | EPOLLPRI)
403 static __cold int io_pollfree_wake(struct io_kiocb *req, struct io_poll *poll)
405 io_poll_mark_cancelled(req);
406 /* we have to kick tw in case it's not already */
407 io_poll_execute(req, 0);
410 * If the waitqueue is being freed early but someone is already
411 * holds ownership over it, we have to tear down the request as
412 * best we can. That means immediately removing the request from
413 * its waitqueue and preventing all further accesses to the
414 * waitqueue via the request.
416 list_del_init(&poll->wait.entry);
419 * Careful: this *must* be the last step, since as soon
420 * as req->head is NULL'ed out, the request can be
421 * completed and freed, since aio_poll_complete_work()
422 * will no longer need to take the waitqueue lock.
424 smp_store_release(&poll->head, NULL);
428 static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
431 struct io_kiocb *req = wqe_to_req(wait);
432 struct io_poll *poll = container_of(wait, struct io_poll, wait);
433 __poll_t mask = key_to_poll(key);
435 if (unlikely(mask & POLLFREE))
436 return io_pollfree_wake(req, poll);
438 /* for instances that support it check for an event match first */
439 if (mask && !(mask & (poll->events & ~IO_ASYNC_POLL_COMMON)))
442 if (io_poll_get_ownership(req)) {
444 * If we trigger a multishot poll off our own wakeup path,
445 * disable multishot as there is a circular dependency between
446 * CQ posting and triggering the event.
448 if (mask & EPOLL_URING_WAKE)
449 poll->events |= EPOLLONESHOT;
451 /* optional, saves extra locking for removal in tw handler */
452 if (mask && poll->events & EPOLLONESHOT) {
453 list_del_init(&poll->wait.entry);
455 if (wqe_is_double(wait))
456 req->flags &= ~REQ_F_DOUBLE_POLL;
458 req->flags &= ~REQ_F_SINGLE_POLL;
460 __io_poll_execute(req, mask);
465 /* fails only when polling is already completing by the first entry */
466 static bool io_poll_double_prepare(struct io_kiocb *req)
468 struct wait_queue_head *head;
469 struct io_poll *poll = io_poll_get_single(req);
471 /* head is RCU protected, see io_poll_remove_entries() comments */
473 head = smp_load_acquire(&poll->head);
475 * poll arm might not hold ownership and so race for req->flags with
476 * io_poll_wake(). There is only one poll entry queued, serialise with
477 * it by taking its head lock. As we're still arming the tw hanlder
478 * is not going to be run, so there are no races with it.
481 spin_lock_irq(&head->lock);
482 req->flags |= REQ_F_DOUBLE_POLL;
483 if (req->opcode == IORING_OP_POLL_ADD)
484 req->flags |= REQ_F_ASYNC_DATA;
485 spin_unlock_irq(&head->lock);
491 static void __io_queue_proc(struct io_poll *poll, struct io_poll_table *pt,
492 struct wait_queue_head *head,
493 struct io_poll **poll_ptr)
495 struct io_kiocb *req = pt->req;
496 unsigned long wqe_private = (unsigned long) req;
499 * The file being polled uses multiple waitqueues for poll handling
500 * (e.g. one for read, one for write). Setup a separate io_poll
503 if (unlikely(pt->nr_entries)) {
504 struct io_poll *first = poll;
506 /* double add on the same waitqueue head, ignore */
507 if (first->head == head)
509 /* already have a 2nd entry, fail a third attempt */
511 if ((*poll_ptr)->head == head)
517 poll = kmalloc(sizeof(*poll), GFP_ATOMIC);
523 /* mark as double wq entry */
524 wqe_private |= IO_WQE_F_DOUBLE;
525 io_init_poll_iocb(poll, first->events);
526 if (!io_poll_double_prepare(req)) {
527 /* the request is completing, just back off */
533 /* fine to modify, there is no poll queued to race with us */
534 req->flags |= REQ_F_SINGLE_POLL;
539 poll->wait.private = (void *) wqe_private;
541 if (poll->events & EPOLLEXCLUSIVE) {
543 * Exclusive waits may only wake a limited amount of entries
544 * rather than all of them, this may interfere with lazy
545 * wake if someone does wait(events > 1). Ensure we don't do
546 * lazy wake for those, as we need to process each one as they
549 req->flags |= REQ_F_POLL_NO_LAZY;
550 add_wait_queue_exclusive(head, &poll->wait);
552 add_wait_queue(head, &poll->wait);
556 static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head,
557 struct poll_table_struct *p)
559 struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
560 struct io_poll *poll = io_kiocb_to_cmd(pt->req, struct io_poll);
562 __io_queue_proc(poll, pt, head,
563 (struct io_poll **) &pt->req->async_data);
566 static bool io_poll_can_finish_inline(struct io_kiocb *req,
567 struct io_poll_table *pt)
569 return pt->owning || io_poll_get_ownership(req);
572 static void io_poll_add_hash(struct io_kiocb *req)
574 if (req->flags & REQ_F_HASH_LOCKED)
575 io_poll_req_insert_locked(req);
577 io_poll_req_insert(req);
581 * Returns 0 when it's handed over for polling. The caller owns the requests if
582 * it returns non-zero, but otherwise should not touch it. Negative values
583 * contain an error code. When the result is >0, the polling has completed
584 * inline and ipt.result_mask is set to the mask.
586 static int __io_arm_poll_handler(struct io_kiocb *req,
587 struct io_poll *poll,
588 struct io_poll_table *ipt, __poll_t mask,
589 unsigned issue_flags)
591 INIT_HLIST_NODE(&req->hash_node);
592 io_init_poll_iocb(poll, mask);
593 poll->file = req->file;
594 req->apoll_events = poll->events;
601 * Polling is either completed here or via task_work, so if we're in the
602 * task context we're naturally serialised with tw by merit of running
603 * the same task. When it's io-wq, take the ownership to prevent tw
604 * from running. However, when we're in the task context, skip taking
605 * it as an optimisation.
607 * Note: even though the request won't be completed/freed, without
608 * ownership we still can race with io_poll_wake().
609 * io_poll_can_finish_inline() tries to deal with that.
611 ipt->owning = issue_flags & IO_URING_F_UNLOCKED;
612 atomic_set(&req->poll_refs, (int)ipt->owning);
614 /* io-wq doesn't hold uring_lock */
615 if (issue_flags & IO_URING_F_UNLOCKED)
616 req->flags &= ~REQ_F_HASH_LOCKED;
618 mask = vfs_poll(req->file, &ipt->pt) & poll->events;
620 if (unlikely(ipt->error || !ipt->nr_entries)) {
621 io_poll_remove_entries(req);
623 if (!io_poll_can_finish_inline(req, ipt)) {
624 io_poll_mark_cancelled(req);
626 } else if (mask && (poll->events & EPOLLET)) {
627 ipt->result_mask = mask;
630 return ipt->error ?: -EINVAL;
634 ((poll->events & (EPOLLET|EPOLLONESHOT)) == (EPOLLET|EPOLLONESHOT))) {
635 if (!io_poll_can_finish_inline(req, ipt)) {
636 io_poll_add_hash(req);
639 io_poll_remove_entries(req);
640 ipt->result_mask = mask;
641 /* no one else has access to the req, forget about the ref */
645 io_poll_add_hash(req);
647 if (mask && (poll->events & EPOLLET) &&
648 io_poll_can_finish_inline(req, ipt)) {
649 __io_poll_execute(req, mask);
655 * Try to release ownership. If we see a change of state, e.g.
656 * poll was waken up, queue up a tw, it'll deal with it.
658 if (atomic_cmpxchg(&req->poll_refs, 1, 0) != 1)
659 __io_poll_execute(req, 0);
664 static void io_async_queue_proc(struct file *file, struct wait_queue_head *head,
665 struct poll_table_struct *p)
667 struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
668 struct async_poll *apoll = pt->req->apoll;
670 __io_queue_proc(&apoll->poll, pt, head, &apoll->double_poll);
674 * We can't reliably detect loops in repeated poll triggers and issue
675 * subsequently failing. But rather than fail these immediately, allow a
676 * certain amount of retries before we give up. Given that this condition
677 * should _rarely_ trigger even once, we should be fine with a larger value.
679 #define APOLL_MAX_RETRY 128
681 static struct async_poll *io_req_alloc_apoll(struct io_kiocb *req,
682 unsigned issue_flags)
684 struct io_ring_ctx *ctx = req->ctx;
685 struct io_cache_entry *entry;
686 struct async_poll *apoll;
688 if (req->flags & REQ_F_POLLED) {
690 kfree(apoll->double_poll);
691 } else if (!(issue_flags & IO_URING_F_UNLOCKED)) {
692 entry = io_alloc_cache_get(&ctx->apoll_cache);
695 apoll = container_of(entry, struct async_poll, cache);
696 apoll->poll.retries = APOLL_MAX_RETRY;
699 apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
700 if (unlikely(!apoll))
702 apoll->poll.retries = APOLL_MAX_RETRY;
704 apoll->double_poll = NULL;
706 if (unlikely(!--apoll->poll.retries))
711 int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags)
713 const struct io_issue_def *def = &io_issue_defs[req->opcode];
714 struct async_poll *apoll;
715 struct io_poll_table ipt;
716 __poll_t mask = POLLPRI | POLLERR | EPOLLET;
720 * apoll requests already grab the mutex to complete in the tw handler,
721 * so removal from the mutex-backed hash is free, use it by default.
723 req->flags |= REQ_F_HASH_LOCKED;
725 if (!def->pollin && !def->pollout)
726 return IO_APOLL_ABORTED;
727 if (!io_file_can_poll(req))
728 return IO_APOLL_ABORTED;
729 if (!(req->flags & REQ_F_APOLL_MULTISHOT))
730 mask |= EPOLLONESHOT;
733 mask |= EPOLLIN | EPOLLRDNORM;
735 /* If reading from MSG_ERRQUEUE using recvmsg, ignore POLLIN */
736 if (req->flags & REQ_F_CLEAR_POLLIN)
739 mask |= EPOLLOUT | EPOLLWRNORM;
741 if (def->poll_exclusive)
742 mask |= EPOLLEXCLUSIVE;
744 apoll = io_req_alloc_apoll(req, issue_flags);
746 return IO_APOLL_ABORTED;
747 req->flags &= ~(REQ_F_SINGLE_POLL | REQ_F_DOUBLE_POLL);
748 req->flags |= REQ_F_POLLED;
749 ipt.pt._qproc = io_async_queue_proc;
751 io_kbuf_recycle(req, issue_flags);
753 ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask, issue_flags);
755 return ret > 0 ? IO_APOLL_READY : IO_APOLL_ABORTED;
756 trace_io_uring_poll_arm(req, mask, apoll->poll.events);
760 static __cold bool io_poll_remove_all_table(struct task_struct *tsk,
761 struct io_hash_table *table,
764 unsigned nr_buckets = 1U << table->hash_bits;
765 struct hlist_node *tmp;
766 struct io_kiocb *req;
770 for (i = 0; i < nr_buckets; i++) {
771 struct io_hash_bucket *hb = &table->hbs[i];
773 spin_lock(&hb->lock);
774 hlist_for_each_entry_safe(req, tmp, &hb->list, hash_node) {
775 if (io_match_task_safe(req, tsk, cancel_all)) {
776 hlist_del_init(&req->hash_node);
777 io_poll_cancel_req(req);
781 spin_unlock(&hb->lock);
787 * Returns true if we found and killed one or more poll requests
789 __cold bool io_poll_remove_all(struct io_ring_ctx *ctx, struct task_struct *tsk,
791 __must_hold(&ctx->uring_lock)
795 ret = io_poll_remove_all_table(tsk, &ctx->cancel_table, cancel_all);
796 ret |= io_poll_remove_all_table(tsk, &ctx->cancel_table_locked, cancel_all);
800 static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, bool poll_only,
801 struct io_cancel_data *cd,
802 struct io_hash_table *table,
803 struct io_hash_bucket **out_bucket)
805 struct io_kiocb *req;
806 u32 index = hash_long(cd->data, table->hash_bits);
807 struct io_hash_bucket *hb = &table->hbs[index];
811 spin_lock(&hb->lock);
812 hlist_for_each_entry(req, &hb->list, hash_node) {
813 if (cd->data != req->cqe.user_data)
815 if (poll_only && req->opcode != IORING_OP_POLL_ADD)
817 if (cd->flags & IORING_ASYNC_CANCEL_ALL) {
818 if (io_cancel_match_sequence(req, cd->seq))
824 spin_unlock(&hb->lock);
828 static struct io_kiocb *io_poll_file_find(struct io_ring_ctx *ctx,
829 struct io_cancel_data *cd,
830 struct io_hash_table *table,
831 struct io_hash_bucket **out_bucket)
833 unsigned nr_buckets = 1U << table->hash_bits;
834 struct io_kiocb *req;
839 for (i = 0; i < nr_buckets; i++) {
840 struct io_hash_bucket *hb = &table->hbs[i];
842 spin_lock(&hb->lock);
843 hlist_for_each_entry(req, &hb->list, hash_node) {
844 if (io_cancel_req_match(req, cd)) {
849 spin_unlock(&hb->lock);
854 static int io_poll_disarm(struct io_kiocb *req)
858 if (!io_poll_get_ownership(req))
860 io_poll_remove_entries(req);
861 hash_del(&req->hash_node);
865 static int __io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd,
866 struct io_hash_table *table)
868 struct io_hash_bucket *bucket;
869 struct io_kiocb *req;
871 if (cd->flags & (IORING_ASYNC_CANCEL_FD | IORING_ASYNC_CANCEL_OP |
872 IORING_ASYNC_CANCEL_ANY))
873 req = io_poll_file_find(ctx, cd, table, &bucket);
875 req = io_poll_find(ctx, false, cd, table, &bucket);
878 io_poll_cancel_req(req);
880 spin_unlock(&bucket->lock);
881 return req ? 0 : -ENOENT;
884 int io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd,
885 unsigned issue_flags)
889 ret = __io_poll_cancel(ctx, cd, &ctx->cancel_table);
893 io_ring_submit_lock(ctx, issue_flags);
894 ret = __io_poll_cancel(ctx, cd, &ctx->cancel_table_locked);
895 io_ring_submit_unlock(ctx, issue_flags);
899 static __poll_t io_poll_parse_events(const struct io_uring_sqe *sqe,
904 events = READ_ONCE(sqe->poll32_events);
906 events = swahw32(events);
908 if (!(flags & IORING_POLL_ADD_MULTI))
909 events |= EPOLLONESHOT;
910 if (!(flags & IORING_POLL_ADD_LEVEL))
912 return demangle_poll(events) |
913 (events & (EPOLLEXCLUSIVE|EPOLLONESHOT|EPOLLET));
916 int io_poll_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
918 struct io_poll_update *upd = io_kiocb_to_cmd(req, struct io_poll_update);
921 if (sqe->buf_index || sqe->splice_fd_in)
923 flags = READ_ONCE(sqe->len);
924 if (flags & ~(IORING_POLL_UPDATE_EVENTS | IORING_POLL_UPDATE_USER_DATA |
925 IORING_POLL_ADD_MULTI))
927 /* meaningless without update */
928 if (flags == IORING_POLL_ADD_MULTI)
931 upd->old_user_data = READ_ONCE(sqe->addr);
932 upd->update_events = flags & IORING_POLL_UPDATE_EVENTS;
933 upd->update_user_data = flags & IORING_POLL_UPDATE_USER_DATA;
935 upd->new_user_data = READ_ONCE(sqe->off);
936 if (!upd->update_user_data && upd->new_user_data)
938 if (upd->update_events)
939 upd->events = io_poll_parse_events(sqe, flags);
940 else if (sqe->poll32_events)
946 int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
948 struct io_poll *poll = io_kiocb_to_cmd(req, struct io_poll);
951 if (sqe->buf_index || sqe->off || sqe->addr)
953 flags = READ_ONCE(sqe->len);
954 if (flags & ~IORING_POLL_ADD_MULTI)
956 if ((flags & IORING_POLL_ADD_MULTI) && (req->flags & REQ_F_CQE_SKIP))
959 poll->events = io_poll_parse_events(sqe, flags);
963 int io_poll_add(struct io_kiocb *req, unsigned int issue_flags)
965 struct io_poll *poll = io_kiocb_to_cmd(req, struct io_poll);
966 struct io_poll_table ipt;
969 ipt.pt._qproc = io_poll_queue_proc;
972 * If sqpoll or single issuer, there is no contention for ->uring_lock
973 * and we'll end up holding it in tw handlers anyway.
975 if (req->ctx->flags & (IORING_SETUP_SQPOLL|IORING_SETUP_SINGLE_ISSUER))
976 req->flags |= REQ_F_HASH_LOCKED;
978 ret = __io_arm_poll_handler(req, poll, &ipt, poll->events, issue_flags);
980 io_req_set_res(req, ipt.result_mask, 0);
983 return ret ?: IOU_ISSUE_SKIP_COMPLETE;
986 int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags)
988 struct io_poll_update *poll_update = io_kiocb_to_cmd(req, struct io_poll_update);
989 struct io_ring_ctx *ctx = req->ctx;
990 struct io_cancel_data cd = { .ctx = ctx, .data = poll_update->old_user_data, };
991 struct io_hash_bucket *bucket;
992 struct io_kiocb *preq;
994 struct io_tw_state ts = { .locked = true };
996 io_ring_submit_lock(ctx, issue_flags);
997 preq = io_poll_find(ctx, true, &cd, &ctx->cancel_table, &bucket);
998 ret2 = io_poll_disarm(preq);
1000 spin_unlock(&bucket->lock);
1003 if (ret2 != -ENOENT) {
1008 preq = io_poll_find(ctx, true, &cd, &ctx->cancel_table_locked, &bucket);
1009 ret2 = io_poll_disarm(preq);
1011 spin_unlock(&bucket->lock);
1018 if (WARN_ON_ONCE(preq->opcode != IORING_OP_POLL_ADD)) {
1023 if (poll_update->update_events || poll_update->update_user_data) {
1024 /* only mask one event flags, keep behavior flags */
1025 if (poll_update->update_events) {
1026 struct io_poll *poll = io_kiocb_to_cmd(preq, struct io_poll);
1028 poll->events &= ~0xffff;
1029 poll->events |= poll_update->events & 0xffff;
1030 poll->events |= IO_POLL_UNMASK;
1032 if (poll_update->update_user_data)
1033 preq->cqe.user_data = poll_update->new_user_data;
1035 ret2 = io_poll_add(preq, issue_flags & ~IO_URING_F_UNLOCKED);
1036 /* successfully updated, don't complete poll request */
1037 if (!ret2 || ret2 == -EIOCBQUEUED)
1042 io_req_set_res(preq, -ECANCELED, 0);
1043 io_req_task_complete(preq, &ts);
1045 io_ring_submit_unlock(ctx, issue_flags);
1050 /* complete update request, we're done with it */
1051 io_req_set_res(req, ret, 0);
1055 void io_apoll_cache_free(struct io_cache_entry *entry)
1057 kfree(container_of(entry, struct async_poll, cache));