1 // SPDX-License-Identifier: GPL-2.0
3 * Shared application/kernel submission and completion ring pairs, for
4 * supporting fast/efficient IO.
6 * A note on the read/write ordering memory barriers that are matched between
7 * the application and kernel side.
9 * After the application reads the CQ ring tail, it must use an
10 * appropriate smp_rmb() to pair with the smp_wmb() the kernel uses
11 * before writing the tail (using smp_load_acquire to read the tail will
12 * do). It also needs a smp_mb() before updating CQ head (ordering the
13 * entry load(s) with the head store), pairing with an implicit barrier
14 * through a control-dependency in io_get_cqe (smp_store_release to
15 * store head will do). Failure to do so could lead to reading invalid
18 * Likewise, the application must use an appropriate smp_wmb() before
19 * writing the SQ tail (ordering SQ entry stores with the tail store),
20 * which pairs with smp_load_acquire in io_get_sqring (smp_store_release
21 * to store the tail will do). And it needs a barrier ordering the SQ
22 * head load before writing new SQ entries (smp_load_acquire to read
25 * When using the SQ poll thread (IORING_SETUP_SQPOLL), the application
26 * needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after*
27 * updating the SQ tail; a full memory barrier smp_mb() is needed
30 * Also see the examples in the liburing library:
32 * git://git.kernel.dk/liburing
34 * io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens
35 * from data shared between the kernel and application. This is done both
36 * for ordering purposes, but also to ensure that once a value is loaded from
37 * data that the application could potentially modify, it remains stable.
39 * Copyright (C) 2018-2019 Jens Axboe
40 * Copyright (c) 2018-2019 Christoph Hellwig
42 #include <linux/kernel.h>
43 #include <linux/init.h>
44 #include <linux/errno.h>
45 #include <linux/syscalls.h>
46 #include <net/compat.h>
47 #include <linux/refcount.h>
48 #include <linux/uio.h>
49 #include <linux/bits.h>
51 #include <linux/sched/signal.h>
53 #include <linux/file.h>
54 #include <linux/fdtable.h>
56 #include <linux/mman.h>
57 #include <linux/percpu.h>
58 #include <linux/slab.h>
59 #include <linux/bvec.h>
60 #include <linux/net.h>
62 #include <net/af_unix.h>
64 #include <linux/anon_inodes.h>
65 #include <linux/sched/mm.h>
66 #include <linux/uaccess.h>
67 #include <linux/nospec.h>
68 #include <linux/highmem.h>
69 #include <linux/fsnotify.h>
70 #include <linux/fadvise.h>
71 #include <linux/task_work.h>
72 #include <linux/io_uring.h>
73 #include <linux/audit.h>
74 #include <linux/security.h>
76 #define CREATE_TRACE_POINTS
77 #include <trace/events/io_uring.h>
79 #include <uapi/linux/io_uring.h>
97 #include "alloc_cache.h"
99 #define IORING_MAX_ENTRIES 32768
100 #define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES)
102 #define IORING_MAX_RESTRICTIONS (IORING_RESTRICTION_LAST + \
103 IORING_REGISTER_LAST + IORING_OP_LAST)
105 #define SQE_COMMON_FLAGS (IOSQE_FIXED_FILE | IOSQE_IO_LINK | \
106 IOSQE_IO_HARDLINK | IOSQE_ASYNC)
108 #define SQE_VALID_FLAGS (SQE_COMMON_FLAGS | IOSQE_BUFFER_SELECT | \
109 IOSQE_IO_DRAIN | IOSQE_CQE_SKIP_SUCCESS)
111 #define IO_REQ_CLEAN_FLAGS (REQ_F_BUFFER_SELECTED | REQ_F_NEED_CLEANUP | \
112 REQ_F_POLLED | REQ_F_INFLIGHT | REQ_F_CREDS | \
115 #define IO_REQ_CLEAN_SLOW_FLAGS (REQ_F_REFCOUNT | REQ_F_LINK | REQ_F_HARDLINK |\
118 #define IO_TCTX_REFS_CACHE_NR (1U << 10)
120 #define IO_COMPL_BATCH 32
121 #define IO_REQ_ALLOC_BATCH 8
124 IO_CHECK_CQ_OVERFLOW_BIT,
125 IO_CHECK_CQ_DROPPED_BIT,
129 IO_EVENTFD_OP_SIGNAL_BIT,
130 IO_EVENTFD_OP_FREE_BIT,
133 struct io_defer_entry {
134 struct list_head list;
135 struct io_kiocb *req;
139 /* requests with any of those set should undergo io_disarm_next() */
140 #define IO_DISARM_MASK (REQ_F_ARM_LTIMEOUT | REQ_F_LINK_TIMEOUT | REQ_F_FAIL)
141 #define IO_REQ_LINK_FLAGS (REQ_F_LINK | REQ_F_HARDLINK)
143 static bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
144 struct task_struct *task,
147 static void io_dismantle_req(struct io_kiocb *req);
148 static void io_clean_op(struct io_kiocb *req);
149 static void io_queue_sqe(struct io_kiocb *req);
150 static void io_move_task_work_from_local(struct io_ring_ctx *ctx);
151 static void __io_submit_flush_completions(struct io_ring_ctx *ctx);
152 static __cold void io_fallback_tw(struct io_uring_task *tctx);
154 struct kmem_cache *req_cachep;
156 struct sock *io_uring_get_socket(struct file *file)
158 #if defined(CONFIG_UNIX)
159 if (io_is_uring_fops(file)) {
160 struct io_ring_ctx *ctx = file->private_data;
162 return ctx->ring_sock->sk;
167 EXPORT_SYMBOL(io_uring_get_socket);
169 static inline void io_submit_flush_completions(struct io_ring_ctx *ctx)
171 if (!wq_list_empty(&ctx->submit_state.compl_reqs) ||
172 ctx->submit_state.cqes_count)
173 __io_submit_flush_completions(ctx);
176 static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx)
178 return ctx->cached_cq_tail - READ_ONCE(ctx->rings->cq.head);
181 static inline unsigned int __io_cqring_events_user(struct io_ring_ctx *ctx)
183 return READ_ONCE(ctx->rings->cq.tail) - READ_ONCE(ctx->rings->cq.head);
186 static bool io_match_linked(struct io_kiocb *head)
188 struct io_kiocb *req;
190 io_for_each_link(req, head) {
191 if (req->flags & REQ_F_INFLIGHT)
198 * As io_match_task() but protected against racing with linked timeouts.
199 * User must not hold timeout_lock.
201 bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,
206 if (task && head->task != task)
211 if (head->flags & REQ_F_LINK_TIMEOUT) {
212 struct io_ring_ctx *ctx = head->ctx;
214 /* protect against races with linked timeouts */
215 spin_lock_irq(&ctx->timeout_lock);
216 matched = io_match_linked(head);
217 spin_unlock_irq(&ctx->timeout_lock);
219 matched = io_match_linked(head);
224 static inline void req_fail_link_node(struct io_kiocb *req, int res)
227 io_req_set_res(req, res, 0);
230 static inline void io_req_add_to_cache(struct io_kiocb *req, struct io_ring_ctx *ctx)
232 wq_stack_add_head(&req->comp_list, &ctx->submit_state.free_list);
233 kasan_poison_object_data(req_cachep, req);
236 static __cold void io_ring_ctx_ref_free(struct percpu_ref *ref)
238 struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs);
240 complete(&ctx->ref_comp);
243 static __cold void io_fallback_req_func(struct work_struct *work)
245 struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx,
247 struct llist_node *node = llist_del_all(&ctx->fallback_llist);
248 struct io_kiocb *req, *tmp;
251 mutex_lock(&ctx->uring_lock);
252 llist_for_each_entry_safe(req, tmp, node, io_task_work.node)
253 req->io_task_work.func(req, &locked);
254 if (WARN_ON_ONCE(!locked))
256 io_submit_flush_completions(ctx);
257 mutex_unlock(&ctx->uring_lock);
260 static int io_alloc_hash_table(struct io_hash_table *table, unsigned bits)
262 unsigned hash_buckets = 1U << bits;
263 size_t hash_size = hash_buckets * sizeof(table->hbs[0]);
265 table->hbs = kmalloc(hash_size, GFP_KERNEL);
269 table->hash_bits = bits;
270 init_hash_table(table, hash_buckets);
274 static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
276 struct io_ring_ctx *ctx;
279 ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
283 xa_init(&ctx->io_bl_xa);
286 * Use 5 bits less than the max cq entries, that should give us around
287 * 32 entries per hash list if totally full and uniformly spread, but
288 * don't keep too many buckets to not overconsume memory.
290 hash_bits = ilog2(p->cq_entries) - 5;
291 hash_bits = clamp(hash_bits, 1, 8);
292 if (io_alloc_hash_table(&ctx->cancel_table, hash_bits))
294 if (io_alloc_hash_table(&ctx->cancel_table_locked, hash_bits))
297 ctx->dummy_ubuf = kzalloc(sizeof(*ctx->dummy_ubuf), GFP_KERNEL);
298 if (!ctx->dummy_ubuf)
300 /* set invalid range, so io_import_fixed() fails meeting it */
301 ctx->dummy_ubuf->ubuf = -1UL;
303 if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free,
307 ctx->flags = p->flags;
308 init_waitqueue_head(&ctx->sqo_sq_wait);
309 INIT_LIST_HEAD(&ctx->sqd_list);
310 INIT_LIST_HEAD(&ctx->cq_overflow_list);
311 INIT_LIST_HEAD(&ctx->io_buffers_cache);
312 io_alloc_cache_init(&ctx->apoll_cache);
313 io_alloc_cache_init(&ctx->netmsg_cache);
314 init_completion(&ctx->ref_comp);
315 xa_init_flags(&ctx->personalities, XA_FLAGS_ALLOC1);
316 mutex_init(&ctx->uring_lock);
317 init_waitqueue_head(&ctx->cq_wait);
318 init_waitqueue_head(&ctx->poll_wq);
319 spin_lock_init(&ctx->completion_lock);
320 spin_lock_init(&ctx->timeout_lock);
321 INIT_WQ_LIST(&ctx->iopoll_list);
322 INIT_LIST_HEAD(&ctx->io_buffers_pages);
323 INIT_LIST_HEAD(&ctx->io_buffers_comp);
324 INIT_LIST_HEAD(&ctx->defer_list);
325 INIT_LIST_HEAD(&ctx->timeout_list);
326 INIT_LIST_HEAD(&ctx->ltimeout_list);
327 spin_lock_init(&ctx->rsrc_ref_lock);
328 INIT_LIST_HEAD(&ctx->rsrc_ref_list);
329 INIT_DELAYED_WORK(&ctx->rsrc_put_work, io_rsrc_put_work);
330 init_task_work(&ctx->rsrc_put_tw, io_rsrc_put_tw);
331 init_llist_head(&ctx->rsrc_put_llist);
332 init_llist_head(&ctx->work_llist);
333 INIT_LIST_HEAD(&ctx->tctx_list);
334 ctx->submit_state.free_list.next = NULL;
335 INIT_WQ_LIST(&ctx->locked_free_list);
336 INIT_DELAYED_WORK(&ctx->fallback_work, io_fallback_req_func);
337 INIT_WQ_LIST(&ctx->submit_state.compl_reqs);
340 kfree(ctx->dummy_ubuf);
341 kfree(ctx->cancel_table.hbs);
342 kfree(ctx->cancel_table_locked.hbs);
344 xa_destroy(&ctx->io_bl_xa);
349 static void io_account_cq_overflow(struct io_ring_ctx *ctx)
351 struct io_rings *r = ctx->rings;
353 WRITE_ONCE(r->cq_overflow, READ_ONCE(r->cq_overflow) + 1);
357 static bool req_need_defer(struct io_kiocb *req, u32 seq)
359 if (unlikely(req->flags & REQ_F_IO_DRAIN)) {
360 struct io_ring_ctx *ctx = req->ctx;
362 return seq + READ_ONCE(ctx->cq_extra) != ctx->cached_cq_tail;
368 static inline void io_req_track_inflight(struct io_kiocb *req)
370 if (!(req->flags & REQ_F_INFLIGHT)) {
371 req->flags |= REQ_F_INFLIGHT;
372 atomic_inc(&req->task->io_uring->inflight_tracked);
376 static struct io_kiocb *__io_prep_linked_timeout(struct io_kiocb *req)
378 if (WARN_ON_ONCE(!req->link))
381 req->flags &= ~REQ_F_ARM_LTIMEOUT;
382 req->flags |= REQ_F_LINK_TIMEOUT;
384 /* linked timeouts should have two refs once prep'ed */
385 io_req_set_refcount(req);
386 __io_req_set_refcount(req->link, 2);
390 static inline struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
392 if (likely(!(req->flags & REQ_F_ARM_LTIMEOUT)))
394 return __io_prep_linked_timeout(req);
397 static noinline void __io_arm_ltimeout(struct io_kiocb *req)
399 io_queue_linked_timeout(__io_prep_linked_timeout(req));
402 static inline void io_arm_ltimeout(struct io_kiocb *req)
404 if (unlikely(req->flags & REQ_F_ARM_LTIMEOUT))
405 __io_arm_ltimeout(req);
408 static void io_prep_async_work(struct io_kiocb *req)
410 const struct io_issue_def *def = &io_issue_defs[req->opcode];
411 struct io_ring_ctx *ctx = req->ctx;
413 if (!(req->flags & REQ_F_CREDS)) {
414 req->flags |= REQ_F_CREDS;
415 req->creds = get_current_cred();
418 req->work.list.next = NULL;
420 req->work.cancel_seq = atomic_read(&ctx->cancel_seq);
421 if (req->flags & REQ_F_FORCE_ASYNC)
422 req->work.flags |= IO_WQ_WORK_CONCURRENT;
424 if (req->file && !io_req_ffs_set(req))
425 req->flags |= io_file_get_flags(req->file) << REQ_F_SUPPORT_NOWAIT_BIT;
427 if (req->flags & REQ_F_ISREG) {
428 bool should_hash = def->hash_reg_file;
430 /* don't serialize this request if the fs doesn't need it */
431 if (should_hash && (req->file->f_flags & O_DIRECT) &&
432 (req->file->f_mode & FMODE_DIO_PARALLEL_WRITE))
434 if (should_hash || (ctx->flags & IORING_SETUP_IOPOLL))
435 io_wq_hash_work(&req->work, file_inode(req->file));
436 } else if (!req->file || !S_ISBLK(file_inode(req->file)->i_mode)) {
437 if (def->unbound_nonreg_file)
438 req->work.flags |= IO_WQ_WORK_UNBOUND;
442 static void io_prep_async_link(struct io_kiocb *req)
444 struct io_kiocb *cur;
446 if (req->flags & REQ_F_LINK_TIMEOUT) {
447 struct io_ring_ctx *ctx = req->ctx;
449 spin_lock_irq(&ctx->timeout_lock);
450 io_for_each_link(cur, req)
451 io_prep_async_work(cur);
452 spin_unlock_irq(&ctx->timeout_lock);
454 io_for_each_link(cur, req)
455 io_prep_async_work(cur);
459 void io_queue_iowq(struct io_kiocb *req, bool *dont_use)
461 struct io_kiocb *link = io_prep_linked_timeout(req);
462 struct io_uring_task *tctx = req->task->io_uring;
465 BUG_ON(!tctx->io_wq);
467 /* init ->work of the whole link before punting */
468 io_prep_async_link(req);
471 * Not expected to happen, but if we do have a bug where this _can_
472 * happen, catch it here and ensure the request is marked as
473 * canceled. That will make io-wq go through the usual work cancel
474 * procedure rather than attempt to run this request (or create a new
477 if (WARN_ON_ONCE(!same_thread_group(req->task, current)))
478 req->work.flags |= IO_WQ_WORK_CANCEL;
480 trace_io_uring_queue_async_work(req, io_wq_is_hashed(&req->work));
481 io_wq_enqueue(tctx->io_wq, &req->work);
483 io_queue_linked_timeout(link);
486 static __cold void io_queue_deferred(struct io_ring_ctx *ctx)
488 while (!list_empty(&ctx->defer_list)) {
489 struct io_defer_entry *de = list_first_entry(&ctx->defer_list,
490 struct io_defer_entry, list);
492 if (req_need_defer(de->req, de->seq))
494 list_del_init(&de->list);
495 io_req_task_queue(de->req);
501 static void io_eventfd_ops(struct rcu_head *rcu)
503 struct io_ev_fd *ev_fd = container_of(rcu, struct io_ev_fd, rcu);
504 int ops = atomic_xchg(&ev_fd->ops, 0);
506 if (ops & BIT(IO_EVENTFD_OP_SIGNAL_BIT))
507 eventfd_signal_mask(ev_fd->cq_ev_fd, 1, EPOLL_URING_WAKE);
509 /* IO_EVENTFD_OP_FREE_BIT may not be set here depending on callback
510 * ordering in a race but if references are 0 we know we have to free
513 if (atomic_dec_and_test(&ev_fd->refs)) {
514 eventfd_ctx_put(ev_fd->cq_ev_fd);
519 static void io_eventfd_signal(struct io_ring_ctx *ctx)
521 struct io_ev_fd *ev_fd = NULL;
525 * rcu_dereference ctx->io_ev_fd once and use it for both for checking
528 ev_fd = rcu_dereference(ctx->io_ev_fd);
531 * Check again if ev_fd exists incase an io_eventfd_unregister call
532 * completed between the NULL check of ctx->io_ev_fd at the start of
533 * the function and rcu_read_lock.
535 if (unlikely(!ev_fd))
537 if (READ_ONCE(ctx->rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED)
539 if (ev_fd->eventfd_async && !io_wq_current_is_worker())
542 if (likely(eventfd_signal_allowed())) {
543 eventfd_signal_mask(ev_fd->cq_ev_fd, 1, EPOLL_URING_WAKE);
545 atomic_inc(&ev_fd->refs);
546 if (!atomic_fetch_or(BIT(IO_EVENTFD_OP_SIGNAL_BIT), &ev_fd->ops))
547 call_rcu_hurry(&ev_fd->rcu, io_eventfd_ops);
549 atomic_dec(&ev_fd->refs);
556 static void io_eventfd_flush_signal(struct io_ring_ctx *ctx)
560 spin_lock(&ctx->completion_lock);
563 * Eventfd should only get triggered when at least one event has been
564 * posted. Some applications rely on the eventfd notification count
565 * only changing IFF a new CQE has been added to the CQ ring. There's
566 * no depedency on 1:1 relationship between how many times this
567 * function is called (and hence the eventfd count) and number of CQEs
568 * posted to the CQ ring.
570 skip = ctx->cached_cq_tail == ctx->evfd_last_cq_tail;
571 ctx->evfd_last_cq_tail = ctx->cached_cq_tail;
572 spin_unlock(&ctx->completion_lock);
576 io_eventfd_signal(ctx);
579 void __io_commit_cqring_flush(struct io_ring_ctx *ctx)
581 if (ctx->poll_activated)
582 io_poll_wq_wake(ctx);
583 if (ctx->off_timeout_used)
584 io_flush_timeouts(ctx);
585 if (ctx->drain_active) {
586 spin_lock(&ctx->completion_lock);
587 io_queue_deferred(ctx);
588 spin_unlock(&ctx->completion_lock);
591 io_eventfd_flush_signal(ctx);
594 static inline void __io_cq_lock(struct io_ring_ctx *ctx)
595 __acquires(ctx->completion_lock)
597 if (!ctx->task_complete)
598 spin_lock(&ctx->completion_lock);
601 static inline void __io_cq_unlock(struct io_ring_ctx *ctx)
603 if (!ctx->task_complete)
604 spin_unlock(&ctx->completion_lock);
607 static inline void io_cq_lock(struct io_ring_ctx *ctx)
608 __acquires(ctx->completion_lock)
610 spin_lock(&ctx->completion_lock);
613 static inline void io_cq_unlock(struct io_ring_ctx *ctx)
614 __releases(ctx->completion_lock)
616 spin_unlock(&ctx->completion_lock);
619 /* keep it inlined for io_submit_flush_completions() */
620 static inline void __io_cq_unlock_post(struct io_ring_ctx *ctx)
621 __releases(ctx->completion_lock)
623 io_commit_cqring(ctx);
625 io_commit_cqring_flush(ctx);
629 static inline void __io_cq_unlock_post_flush(struct io_ring_ctx *ctx)
630 __releases(ctx->completion_lock)
632 io_commit_cqring(ctx);
634 io_commit_cqring_flush(ctx);
637 * As ->task_complete implies that the ring is single tasked, cq_wait
638 * may only be waited on by the current in io_cqring_wait(), but since
639 * it will re-check the wakeup conditions once we return we can safely
642 if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) {
644 __io_cqring_wake(ctx);
648 void io_cq_unlock_post(struct io_ring_ctx *ctx)
649 __releases(ctx->completion_lock)
651 io_commit_cqring(ctx);
652 spin_unlock(&ctx->completion_lock);
653 io_commit_cqring_flush(ctx);
657 /* Returns true if there are no backlogged entries after the flush */
658 static void io_cqring_overflow_kill(struct io_ring_ctx *ctx)
660 struct io_overflow_cqe *ocqe;
664 list_splice_init(&ctx->cq_overflow_list, &list);
665 clear_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
668 while (!list_empty(&list)) {
669 ocqe = list_first_entry(&list, struct io_overflow_cqe, list);
670 list_del(&ocqe->list);
675 static void __io_cqring_overflow_flush(struct io_ring_ctx *ctx)
677 size_t cqe_size = sizeof(struct io_uring_cqe);
679 if (__io_cqring_events(ctx) == ctx->cq_entries)
682 if (ctx->flags & IORING_SETUP_CQE32)
686 while (!list_empty(&ctx->cq_overflow_list)) {
687 struct io_uring_cqe *cqe = io_get_cqe_overflow(ctx, true);
688 struct io_overflow_cqe *ocqe;
692 ocqe = list_first_entry(&ctx->cq_overflow_list,
693 struct io_overflow_cqe, list);
694 memcpy(cqe, &ocqe->cqe, cqe_size);
695 list_del(&ocqe->list);
699 if (list_empty(&ctx->cq_overflow_list)) {
700 clear_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
701 atomic_andnot(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags);
703 io_cq_unlock_post(ctx);
706 static void io_cqring_do_overflow_flush(struct io_ring_ctx *ctx)
708 /* iopoll syncs against uring_lock, not completion_lock */
709 if (ctx->flags & IORING_SETUP_IOPOLL)
710 mutex_lock(&ctx->uring_lock);
711 __io_cqring_overflow_flush(ctx);
712 if (ctx->flags & IORING_SETUP_IOPOLL)
713 mutex_unlock(&ctx->uring_lock);
716 static void io_cqring_overflow_flush(struct io_ring_ctx *ctx)
718 if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq))
719 io_cqring_do_overflow_flush(ctx);
722 /* can be called by any task */
723 static void io_put_task_remote(struct task_struct *task, int nr)
725 struct io_uring_task *tctx = task->io_uring;
727 percpu_counter_sub(&tctx->inflight, nr);
728 if (unlikely(atomic_read(&tctx->in_cancel)))
729 wake_up(&tctx->wait);
730 put_task_struct_many(task, nr);
733 /* used by a task to put its own references */
734 static void io_put_task_local(struct task_struct *task, int nr)
736 task->io_uring->cached_refs += nr;
739 /* must to be called somewhat shortly after putting a request */
740 static inline void io_put_task(struct task_struct *task, int nr)
742 if (likely(task == current))
743 io_put_task_local(task, nr);
745 io_put_task_remote(task, nr);
748 void io_task_refs_refill(struct io_uring_task *tctx)
750 unsigned int refill = -tctx->cached_refs + IO_TCTX_REFS_CACHE_NR;
752 percpu_counter_add(&tctx->inflight, refill);
753 refcount_add(refill, ¤t->usage);
754 tctx->cached_refs += refill;
757 static __cold void io_uring_drop_tctx_refs(struct task_struct *task)
759 struct io_uring_task *tctx = task->io_uring;
760 unsigned int refs = tctx->cached_refs;
763 tctx->cached_refs = 0;
764 percpu_counter_sub(&tctx->inflight, refs);
765 put_task_struct_many(task, refs);
769 static bool io_cqring_event_overflow(struct io_ring_ctx *ctx, u64 user_data,
770 s32 res, u32 cflags, u64 extra1, u64 extra2)
772 struct io_overflow_cqe *ocqe;
773 size_t ocq_size = sizeof(struct io_overflow_cqe);
774 bool is_cqe32 = (ctx->flags & IORING_SETUP_CQE32);
776 lockdep_assert_held(&ctx->completion_lock);
779 ocq_size += sizeof(struct io_uring_cqe);
781 ocqe = kmalloc(ocq_size, GFP_ATOMIC | __GFP_ACCOUNT);
782 trace_io_uring_cqe_overflow(ctx, user_data, res, cflags, ocqe);
785 * If we're in ring overflow flush mode, or in task cancel mode,
786 * or cannot allocate an overflow entry, then we need to drop it
789 io_account_cq_overflow(ctx);
790 set_bit(IO_CHECK_CQ_DROPPED_BIT, &ctx->check_cq);
793 if (list_empty(&ctx->cq_overflow_list)) {
794 set_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
795 atomic_or(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags);
798 ocqe->cqe.user_data = user_data;
800 ocqe->cqe.flags = cflags;
802 ocqe->cqe.big_cqe[0] = extra1;
803 ocqe->cqe.big_cqe[1] = extra2;
805 list_add_tail(&ocqe->list, &ctx->cq_overflow_list);
809 bool io_req_cqe_overflow(struct io_kiocb *req)
811 if (!(req->flags & REQ_F_CQE32_INIT)) {
815 return io_cqring_event_overflow(req->ctx, req->cqe.user_data,
816 req->cqe.res, req->cqe.flags,
817 req->extra1, req->extra2);
821 * writes to the cq entry need to come after reading head; the
822 * control dependency is enough as we're using WRITE_ONCE to
825 struct io_uring_cqe *__io_get_cqe(struct io_ring_ctx *ctx, bool overflow)
827 struct io_rings *rings = ctx->rings;
828 unsigned int off = ctx->cached_cq_tail & (ctx->cq_entries - 1);
829 unsigned int free, queued, len;
832 * Posting into the CQ when there are pending overflowed CQEs may break
833 * ordering guarantees, which will affect links, F_MORE users and more.
834 * Force overflow the completion.
836 if (!overflow && (ctx->check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT)))
839 /* userspace may cheat modifying the tail, be safe and do min */
840 queued = min(__io_cqring_events(ctx), ctx->cq_entries);
841 free = ctx->cq_entries - queued;
842 /* we need a contiguous range, limit based on the current array offset */
843 len = min(free, ctx->cq_entries - off);
847 if (ctx->flags & IORING_SETUP_CQE32) {
852 ctx->cqe_cached = &rings->cqes[off];
853 ctx->cqe_sentinel = ctx->cqe_cached + len;
855 ctx->cached_cq_tail++;
857 if (ctx->flags & IORING_SETUP_CQE32)
859 return &rings->cqes[off];
862 static bool io_fill_cqe_aux(struct io_ring_ctx *ctx, u64 user_data, s32 res,
865 struct io_uring_cqe *cqe;
870 * If we can't get a cq entry, userspace overflowed the
871 * submission (by quite a lot). Increment the overflow count in
874 cqe = io_get_cqe(ctx);
876 trace_io_uring_complete(ctx, NULL, user_data, res, cflags, 0, 0);
878 WRITE_ONCE(cqe->user_data, user_data);
879 WRITE_ONCE(cqe->res, res);
880 WRITE_ONCE(cqe->flags, cflags);
882 if (ctx->flags & IORING_SETUP_CQE32) {
883 WRITE_ONCE(cqe->big_cqe[0], 0);
884 WRITE_ONCE(cqe->big_cqe[1], 0);
891 static void __io_flush_post_cqes(struct io_ring_ctx *ctx)
892 __must_hold(&ctx->uring_lock)
894 struct io_submit_state *state = &ctx->submit_state;
897 lockdep_assert_held(&ctx->uring_lock);
898 for (i = 0; i < state->cqes_count; i++) {
899 struct io_uring_cqe *cqe = &state->cqes[i];
901 if (!io_fill_cqe_aux(ctx, cqe->user_data, cqe->res, cqe->flags)) {
902 if (ctx->task_complete) {
903 spin_lock(&ctx->completion_lock);
904 io_cqring_event_overflow(ctx, cqe->user_data,
905 cqe->res, cqe->flags, 0, 0);
906 spin_unlock(&ctx->completion_lock);
908 io_cqring_event_overflow(ctx, cqe->user_data,
909 cqe->res, cqe->flags, 0, 0);
913 state->cqes_count = 0;
916 static bool __io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags,
922 filled = io_fill_cqe_aux(ctx, user_data, res, cflags);
923 if (!filled && allow_overflow)
924 filled = io_cqring_event_overflow(ctx, user_data, res, cflags, 0, 0);
926 io_cq_unlock_post(ctx);
930 bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags)
932 return __io_post_aux_cqe(ctx, user_data, res, cflags, true);
935 bool io_aux_cqe(struct io_ring_ctx *ctx, bool defer, u64 user_data, s32 res, u32 cflags,
938 struct io_uring_cqe *cqe;
942 return __io_post_aux_cqe(ctx, user_data, res, cflags, allow_overflow);
944 length = ARRAY_SIZE(ctx->submit_state.cqes);
946 lockdep_assert_held(&ctx->uring_lock);
948 if (ctx->submit_state.cqes_count == length) {
950 __io_flush_post_cqes(ctx);
951 /* no need to flush - flush is deferred */
952 __io_cq_unlock_post(ctx);
955 /* For defered completions this is not as strict as it is otherwise,
956 * however it's main job is to prevent unbounded posted completions,
957 * and in that it works just as well.
959 if (!allow_overflow && test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq))
962 cqe = &ctx->submit_state.cqes[ctx->submit_state.cqes_count++];
963 cqe->user_data = user_data;
969 static void __io_req_complete_post(struct io_kiocb *req)
971 struct io_ring_ctx *ctx = req->ctx;
974 if (!(req->flags & REQ_F_CQE_SKIP))
975 io_fill_cqe_req(ctx, req);
978 * If we're the last reference to this request, add to our locked
981 if (req_ref_put_and_test(req)) {
982 if (req->flags & IO_REQ_LINK_FLAGS) {
983 if (req->flags & IO_DISARM_MASK)
986 io_req_task_queue(req->link);
990 io_put_kbuf_comp(req);
991 io_dismantle_req(req);
992 io_req_put_rsrc(req);
994 * Selected buffer deallocation in io_clean_op() assumes that
995 * we don't hold ->completion_lock. Clean them here to avoid
998 io_put_task_remote(req->task, 1);
999 wq_list_add_head(&req->comp_list, &ctx->locked_free_list);
1000 ctx->locked_free_nr++;
1002 io_cq_unlock_post(ctx);
1005 void io_req_complete_post(struct io_kiocb *req, unsigned issue_flags)
1007 if (req->ctx->task_complete && (issue_flags & IO_URING_F_IOWQ)) {
1008 req->io_task_work.func = io_req_task_complete;
1009 io_req_task_work_add(req);
1010 } else if (!(issue_flags & IO_URING_F_UNLOCKED) ||
1011 !(req->ctx->flags & IORING_SETUP_IOPOLL)) {
1012 __io_req_complete_post(req);
1014 struct io_ring_ctx *ctx = req->ctx;
1016 mutex_lock(&ctx->uring_lock);
1017 __io_req_complete_post(req);
1018 mutex_unlock(&ctx->uring_lock);
1022 void io_req_defer_failed(struct io_kiocb *req, s32 res)
1023 __must_hold(&ctx->uring_lock)
1025 const struct io_cold_def *def = &io_cold_defs[req->opcode];
1027 lockdep_assert_held(&req->ctx->uring_lock);
1030 io_req_set_res(req, res, io_put_kbuf(req, IO_URING_F_UNLOCKED));
1033 io_req_complete_defer(req);
1037 * Don't initialise the fields below on every allocation, but do that in
1038 * advance and keep them valid across allocations.
1040 static void io_preinit_req(struct io_kiocb *req, struct io_ring_ctx *ctx)
1044 req->async_data = NULL;
1045 /* not necessary, but safer to zero */
1049 static void io_flush_cached_locked_reqs(struct io_ring_ctx *ctx,
1050 struct io_submit_state *state)
1052 spin_lock(&ctx->completion_lock);
1053 wq_list_splice(&ctx->locked_free_list, &state->free_list);
1054 ctx->locked_free_nr = 0;
1055 spin_unlock(&ctx->completion_lock);
1059 * A request might get retired back into the request caches even before opcode
1060 * handlers and io_issue_sqe() are done with it, e.g. inline completion path.
1061 * Because of that, io_alloc_req() should be called only under ->uring_lock
1062 * and with extra caution to not get a request that is still worked on.
1064 __cold bool __io_alloc_req_refill(struct io_ring_ctx *ctx)
1065 __must_hold(&ctx->uring_lock)
1067 gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
1068 void *reqs[IO_REQ_ALLOC_BATCH];
1072 * If we have more than a batch's worth of requests in our IRQ side
1073 * locked cache, grab the lock and move them over to our submission
1076 if (data_race(ctx->locked_free_nr) > IO_COMPL_BATCH) {
1077 io_flush_cached_locked_reqs(ctx, &ctx->submit_state);
1078 if (!io_req_cache_empty(ctx))
1082 ret = kmem_cache_alloc_bulk(req_cachep, gfp, ARRAY_SIZE(reqs), reqs);
1085 * Bulk alloc is all-or-nothing. If we fail to get a batch,
1086 * retry single alloc to be on the safe side.
1088 if (unlikely(ret <= 0)) {
1089 reqs[0] = kmem_cache_alloc(req_cachep, gfp);
1095 percpu_ref_get_many(&ctx->refs, ret);
1096 for (i = 0; i < ret; i++) {
1097 struct io_kiocb *req = reqs[i];
1099 io_preinit_req(req, ctx);
1100 io_req_add_to_cache(req, ctx);
1105 static inline void io_dismantle_req(struct io_kiocb *req)
1107 unsigned int flags = req->flags;
1109 if (unlikely(flags & IO_REQ_CLEAN_FLAGS))
1111 if (!(flags & REQ_F_FIXED_FILE))
1112 io_put_file(req->file);
1115 __cold void io_free_req(struct io_kiocb *req)
1117 struct io_ring_ctx *ctx = req->ctx;
1119 io_req_put_rsrc(req);
1120 io_dismantle_req(req);
1121 io_put_task_remote(req->task, 1);
1123 spin_lock(&ctx->completion_lock);
1124 wq_list_add_head(&req->comp_list, &ctx->locked_free_list);
1125 ctx->locked_free_nr++;
1126 spin_unlock(&ctx->completion_lock);
1129 static void __io_req_find_next_prep(struct io_kiocb *req)
1131 struct io_ring_ctx *ctx = req->ctx;
1133 spin_lock(&ctx->completion_lock);
1134 io_disarm_next(req);
1135 spin_unlock(&ctx->completion_lock);
1138 static inline struct io_kiocb *io_req_find_next(struct io_kiocb *req)
1140 struct io_kiocb *nxt;
1143 * If LINK is set, we have dependent requests in this chain. If we
1144 * didn't fail this request, queue the first one up, moving any other
1145 * dependencies to the next request. In case of failure, fail the rest
1148 if (unlikely(req->flags & IO_DISARM_MASK))
1149 __io_req_find_next_prep(req);
1155 static void ctx_flush_and_put(struct io_ring_ctx *ctx, bool *locked)
1159 if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
1160 atomic_andnot(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
1162 io_submit_flush_completions(ctx);
1163 mutex_unlock(&ctx->uring_lock);
1166 percpu_ref_put(&ctx->refs);
1169 static unsigned int handle_tw_list(struct llist_node *node,
1170 struct io_ring_ctx **ctx, bool *locked,
1171 struct llist_node *last)
1173 unsigned int count = 0;
1175 while (node && node != last) {
1176 struct llist_node *next = node->next;
1177 struct io_kiocb *req = container_of(node, struct io_kiocb,
1180 prefetch(container_of(next, struct io_kiocb, io_task_work.node));
1182 if (req->ctx != *ctx) {
1183 ctx_flush_and_put(*ctx, locked);
1185 /* if not contended, grab and improve batching */
1186 *locked = mutex_trylock(&(*ctx)->uring_lock);
1187 percpu_ref_get(&(*ctx)->refs);
1188 } else if (!*locked)
1189 *locked = mutex_trylock(&(*ctx)->uring_lock);
1190 req->io_task_work.func(req, locked);
1193 if (unlikely(need_resched())) {
1194 ctx_flush_and_put(*ctx, locked);
1204 * io_llist_xchg - swap all entries in a lock-less list
1205 * @head: the head of lock-less list to delete all entries
1206 * @new: new entry as the head of the list
1208 * If list is empty, return NULL, otherwise, return the pointer to the first entry.
1209 * The order of entries returned is from the newest to the oldest added one.
1211 static inline struct llist_node *io_llist_xchg(struct llist_head *head,
1212 struct llist_node *new)
1214 return xchg(&head->first, new);
1218 * io_llist_cmpxchg - possibly swap all entries in a lock-less list
1219 * @head: the head of lock-less list to delete all entries
1220 * @old: expected old value of the first entry of the list
1221 * @new: new entry as the head of the list
1223 * perform a cmpxchg on the first entry of the list.
1226 static inline struct llist_node *io_llist_cmpxchg(struct llist_head *head,
1227 struct llist_node *old,
1228 struct llist_node *new)
1230 return cmpxchg(&head->first, old, new);
1233 void tctx_task_work(struct callback_head *cb)
1235 bool uring_locked = false;
1236 struct io_ring_ctx *ctx = NULL;
1237 struct io_uring_task *tctx = container_of(cb, struct io_uring_task,
1239 struct llist_node fake = {};
1240 struct llist_node *node;
1241 unsigned int loops = 0;
1242 unsigned int count = 0;
1244 if (unlikely(current->flags & PF_EXITING)) {
1245 io_fallback_tw(tctx);
1251 node = io_llist_xchg(&tctx->task_list, &fake);
1252 count += handle_tw_list(node, &ctx, &uring_locked, &fake);
1254 /* skip expensive cmpxchg if there are items in the list */
1255 if (READ_ONCE(tctx->task_list.first) != &fake)
1257 if (uring_locked && !wq_list_empty(&ctx->submit_state.compl_reqs)) {
1258 io_submit_flush_completions(ctx);
1259 if (READ_ONCE(tctx->task_list.first) != &fake)
1262 node = io_llist_cmpxchg(&tctx->task_list, &fake, NULL);
1263 } while (node != &fake);
1265 ctx_flush_and_put(ctx, &uring_locked);
1267 /* relaxed read is enough as only the task itself sets ->in_cancel */
1268 if (unlikely(atomic_read(&tctx->in_cancel)))
1269 io_uring_drop_tctx_refs(current);
1271 trace_io_uring_task_work_run(tctx, count, loops);
1274 static __cold void io_fallback_tw(struct io_uring_task *tctx)
1276 struct llist_node *node = llist_del_all(&tctx->task_list);
1277 struct io_kiocb *req;
1280 req = container_of(node, struct io_kiocb, io_task_work.node);
1282 if (llist_add(&req->io_task_work.node,
1283 &req->ctx->fallback_llist))
1284 schedule_delayed_work(&req->ctx->fallback_work, 1);
1288 static void io_req_local_work_add(struct io_kiocb *req)
1290 struct io_ring_ctx *ctx = req->ctx;
1292 percpu_ref_get(&ctx->refs);
1294 if (!llist_add(&req->io_task_work.node, &ctx->work_llist))
1297 /* needed for the following wake up */
1298 smp_mb__after_atomic();
1300 if (unlikely(atomic_read(&req->task->io_uring->in_cancel))) {
1301 io_move_task_work_from_local(ctx);
1305 if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
1306 atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
1308 io_eventfd_signal(ctx);
1310 if (READ_ONCE(ctx->cq_waiting))
1311 wake_up_state(ctx->submitter_task, TASK_INTERRUPTIBLE);
1314 percpu_ref_put(&ctx->refs);
1317 void __io_req_task_work_add(struct io_kiocb *req, bool allow_local)
1319 struct io_uring_task *tctx = req->task->io_uring;
1320 struct io_ring_ctx *ctx = req->ctx;
1322 if (allow_local && ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
1323 io_req_local_work_add(req);
1327 /* task_work already pending, we're done */
1328 if (!llist_add(&req->io_task_work.node, &tctx->task_list))
1331 if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
1332 atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
1334 if (likely(!task_work_add(req->task, &tctx->task_work, ctx->notify_method)))
1337 io_fallback_tw(tctx);
1340 static void __cold io_move_task_work_from_local(struct io_ring_ctx *ctx)
1342 struct llist_node *node;
1344 node = llist_del_all(&ctx->work_llist);
1346 struct io_kiocb *req = container_of(node, struct io_kiocb,
1350 __io_req_task_work_add(req, false);
1354 static int __io_run_local_work(struct io_ring_ctx *ctx, bool *locked)
1356 struct llist_node *node;
1357 unsigned int loops = 0;
1360 if (WARN_ON_ONCE(ctx->submitter_task != current))
1362 if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
1363 atomic_andnot(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
1365 node = io_llist_xchg(&ctx->work_llist, NULL);
1367 struct llist_node *next = node->next;
1368 struct io_kiocb *req = container_of(node, struct io_kiocb,
1370 prefetch(container_of(next, struct io_kiocb, io_task_work.node));
1371 req->io_task_work.func(req, locked);
1377 if (!llist_empty(&ctx->work_llist))
1380 io_submit_flush_completions(ctx);
1381 if (!llist_empty(&ctx->work_llist))
1384 trace_io_uring_local_work_run(ctx, ret, loops);
1388 static inline int io_run_local_work_locked(struct io_ring_ctx *ctx)
1393 if (llist_empty(&ctx->work_llist))
1397 ret = __io_run_local_work(ctx, &locked);
1398 /* shouldn't happen! */
1399 if (WARN_ON_ONCE(!locked))
1400 mutex_lock(&ctx->uring_lock);
1404 static int io_run_local_work(struct io_ring_ctx *ctx)
1406 bool locked = mutex_trylock(&ctx->uring_lock);
1409 ret = __io_run_local_work(ctx, &locked);
1411 mutex_unlock(&ctx->uring_lock);
1416 static void io_req_task_cancel(struct io_kiocb *req, bool *locked)
1418 io_tw_lock(req->ctx, locked);
1419 io_req_defer_failed(req, req->cqe.res);
1422 void io_req_task_submit(struct io_kiocb *req, bool *locked)
1424 io_tw_lock(req->ctx, locked);
1425 /* req->task == current here, checking PF_EXITING is safe */
1426 if (unlikely(req->task->flags & PF_EXITING))
1427 io_req_defer_failed(req, -EFAULT);
1428 else if (req->flags & REQ_F_FORCE_ASYNC)
1429 io_queue_iowq(req, locked);
1434 void io_req_task_queue_fail(struct io_kiocb *req, int ret)
1436 io_req_set_res(req, ret, 0);
1437 req->io_task_work.func = io_req_task_cancel;
1438 io_req_task_work_add(req);
1441 void io_req_task_queue(struct io_kiocb *req)
1443 req->io_task_work.func = io_req_task_submit;
1444 io_req_task_work_add(req);
1447 void io_queue_next(struct io_kiocb *req)
1449 struct io_kiocb *nxt = io_req_find_next(req);
1452 io_req_task_queue(nxt);
1455 void io_free_batch_list(struct io_ring_ctx *ctx, struct io_wq_work_node *node)
1456 __must_hold(&ctx->uring_lock)
1458 struct task_struct *task = NULL;
1462 struct io_kiocb *req = container_of(node, struct io_kiocb,
1465 if (unlikely(req->flags & IO_REQ_CLEAN_SLOW_FLAGS)) {
1466 if (req->flags & REQ_F_REFCOUNT) {
1467 node = req->comp_list.next;
1468 if (!req_ref_put_and_test(req))
1471 if ((req->flags & REQ_F_POLLED) && req->apoll) {
1472 struct async_poll *apoll = req->apoll;
1474 if (apoll->double_poll)
1475 kfree(apoll->double_poll);
1476 if (!io_alloc_cache_put(&ctx->apoll_cache, &apoll->cache))
1478 req->flags &= ~REQ_F_POLLED;
1480 if (req->flags & IO_REQ_LINK_FLAGS)
1482 if (unlikely(req->flags & IO_REQ_CLEAN_FLAGS))
1485 if (!(req->flags & REQ_F_FIXED_FILE))
1486 io_put_file(req->file);
1488 io_req_put_rsrc_locked(req, ctx);
1490 if (req->task != task) {
1492 io_put_task(task, task_refs);
1497 node = req->comp_list.next;
1498 io_req_add_to_cache(req, ctx);
1502 io_put_task(task, task_refs);
1505 static void __io_submit_flush_completions(struct io_ring_ctx *ctx)
1506 __must_hold(&ctx->uring_lock)
1508 struct io_submit_state *state = &ctx->submit_state;
1509 struct io_wq_work_node *node;
1512 /* must come first to preserve CQE ordering in failure cases */
1513 if (state->cqes_count)
1514 __io_flush_post_cqes(ctx);
1515 __wq_list_for_each(node, &state->compl_reqs) {
1516 struct io_kiocb *req = container_of(node, struct io_kiocb,
1519 if (!(req->flags & REQ_F_CQE_SKIP) &&
1520 unlikely(!__io_fill_cqe_req(ctx, req))) {
1521 if (ctx->task_complete) {
1522 spin_lock(&ctx->completion_lock);
1523 io_req_cqe_overflow(req);
1524 spin_unlock(&ctx->completion_lock);
1526 io_req_cqe_overflow(req);
1530 __io_cq_unlock_post_flush(ctx);
1532 if (!wq_list_empty(&ctx->submit_state.compl_reqs)) {
1533 io_free_batch_list(ctx, state->compl_reqs.first);
1534 INIT_WQ_LIST(&state->compl_reqs);
1539 * Drop reference to request, return next in chain (if there is one) if this
1540 * was the last reference to this request.
1542 static inline struct io_kiocb *io_put_req_find_next(struct io_kiocb *req)
1544 struct io_kiocb *nxt = NULL;
1546 if (req_ref_put_and_test(req)) {
1547 if (unlikely(req->flags & IO_REQ_LINK_FLAGS))
1548 nxt = io_req_find_next(req);
1554 static unsigned io_cqring_events(struct io_ring_ctx *ctx)
1556 /* See comment at the top of this file */
1558 return __io_cqring_events(ctx);
1562 * We can't just wait for polled events to come to us, we have to actively
1563 * find and complete them.
1565 static __cold void io_iopoll_try_reap_events(struct io_ring_ctx *ctx)
1567 if (!(ctx->flags & IORING_SETUP_IOPOLL))
1570 mutex_lock(&ctx->uring_lock);
1571 while (!wq_list_empty(&ctx->iopoll_list)) {
1572 /* let it sleep and repeat later if can't complete a request */
1573 if (io_do_iopoll(ctx, true) == 0)
1576 * Ensure we allow local-to-the-cpu processing to take place,
1577 * in this case we need to ensure that we reap all events.
1578 * Also let task_work, etc. to progress by releasing the mutex
1580 if (need_resched()) {
1581 mutex_unlock(&ctx->uring_lock);
1583 mutex_lock(&ctx->uring_lock);
1586 mutex_unlock(&ctx->uring_lock);
1589 static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
1591 unsigned int nr_events = 0;
1593 unsigned long check_cq;
1595 if (!io_allowed_run_tw(ctx))
1598 check_cq = READ_ONCE(ctx->check_cq);
1599 if (unlikely(check_cq)) {
1600 if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
1601 __io_cqring_overflow_flush(ctx);
1603 * Similarly do not spin if we have not informed the user of any
1606 if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT))
1610 * Don't enter poll loop if we already have events pending.
1611 * If we do, we can potentially be spinning for commands that
1612 * already triggered a CQE (eg in error).
1614 if (io_cqring_events(ctx))
1619 * If a submit got punted to a workqueue, we can have the
1620 * application entering polling for a command before it gets
1621 * issued. That app will hold the uring_lock for the duration
1622 * of the poll right here, so we need to take a breather every
1623 * now and then to ensure that the issue has a chance to add
1624 * the poll to the issued list. Otherwise we can spin here
1625 * forever, while the workqueue is stuck trying to acquire the
1628 if (wq_list_empty(&ctx->iopoll_list) ||
1629 io_task_work_pending(ctx)) {
1630 u32 tail = ctx->cached_cq_tail;
1632 (void) io_run_local_work_locked(ctx);
1634 if (task_work_pending(current) ||
1635 wq_list_empty(&ctx->iopoll_list)) {
1636 mutex_unlock(&ctx->uring_lock);
1638 mutex_lock(&ctx->uring_lock);
1640 /* some requests don't go through iopoll_list */
1641 if (tail != ctx->cached_cq_tail ||
1642 wq_list_empty(&ctx->iopoll_list))
1645 ret = io_do_iopoll(ctx, !min);
1650 } while (nr_events < min && !need_resched());
1655 void io_req_task_complete(struct io_kiocb *req, bool *locked)
1658 io_req_complete_defer(req);
1660 io_req_complete_post(req, IO_URING_F_UNLOCKED);
1664 * After the iocb has been issued, it's safe to be found on the poll list.
1665 * Adding the kiocb to the list AFTER submission ensures that we don't
1666 * find it from a io_do_iopoll() thread before the issuer is done
1667 * accessing the kiocb cookie.
1669 static void io_iopoll_req_issued(struct io_kiocb *req, unsigned int issue_flags)
1671 struct io_ring_ctx *ctx = req->ctx;
1672 const bool needs_lock = issue_flags & IO_URING_F_UNLOCKED;
1674 /* workqueue context doesn't hold uring_lock, grab it now */
1675 if (unlikely(needs_lock))
1676 mutex_lock(&ctx->uring_lock);
1679 * Track whether we have multiple files in our lists. This will impact
1680 * how we do polling eventually, not spinning if we're on potentially
1681 * different devices.
1683 if (wq_list_empty(&ctx->iopoll_list)) {
1684 ctx->poll_multi_queue = false;
1685 } else if (!ctx->poll_multi_queue) {
1686 struct io_kiocb *list_req;
1688 list_req = container_of(ctx->iopoll_list.first, struct io_kiocb,
1690 if (list_req->file != req->file)
1691 ctx->poll_multi_queue = true;
1695 * For fast devices, IO may have already completed. If it has, add
1696 * it to the front so we find it first.
1698 if (READ_ONCE(req->iopoll_completed))
1699 wq_list_add_head(&req->comp_list, &ctx->iopoll_list);
1701 wq_list_add_tail(&req->comp_list, &ctx->iopoll_list);
1703 if (unlikely(needs_lock)) {
1705 * If IORING_SETUP_SQPOLL is enabled, sqes are either handle
1706 * in sq thread task context or in io worker task context. If
1707 * current task context is sq thread, we don't need to check
1708 * whether should wake up sq thread.
1710 if ((ctx->flags & IORING_SETUP_SQPOLL) &&
1711 wq_has_sleeper(&ctx->sq_data->wait))
1712 wake_up(&ctx->sq_data->wait);
1714 mutex_unlock(&ctx->uring_lock);
1718 static bool io_bdev_nowait(struct block_device *bdev)
1720 return !bdev || bdev_nowait(bdev);
1724 * If we tracked the file through the SCM inflight mechanism, we could support
1725 * any file. For now, just ensure that anything potentially problematic is done
1728 static bool __io_file_supports_nowait(struct file *file, umode_t mode)
1730 if (S_ISBLK(mode)) {
1731 if (IS_ENABLED(CONFIG_BLOCK) &&
1732 io_bdev_nowait(I_BDEV(file->f_mapping->host)))
1738 if (S_ISREG(mode)) {
1739 if (IS_ENABLED(CONFIG_BLOCK) &&
1740 io_bdev_nowait(file->f_inode->i_sb->s_bdev) &&
1741 !io_is_uring_fops(file))
1746 /* any ->read/write should understand O_NONBLOCK */
1747 if (file->f_flags & O_NONBLOCK)
1749 return file->f_mode & FMODE_NOWAIT;
1753 * If we tracked the file through the SCM inflight mechanism, we could support
1754 * any file. For now, just ensure that anything potentially problematic is done
1757 unsigned int io_file_get_flags(struct file *file)
1759 umode_t mode = file_inode(file)->i_mode;
1760 unsigned int res = 0;
1764 if (__io_file_supports_nowait(file, mode))
1769 bool io_alloc_async_data(struct io_kiocb *req)
1771 WARN_ON_ONCE(!io_cold_defs[req->opcode].async_size);
1772 req->async_data = kmalloc(io_cold_defs[req->opcode].async_size, GFP_KERNEL);
1773 if (req->async_data) {
1774 req->flags |= REQ_F_ASYNC_DATA;
1780 int io_req_prep_async(struct io_kiocb *req)
1782 const struct io_cold_def *cdef = &io_cold_defs[req->opcode];
1783 const struct io_issue_def *def = &io_issue_defs[req->opcode];
1785 /* assign early for deferred execution for non-fixed file */
1786 if (def->needs_file && !(req->flags & REQ_F_FIXED_FILE) && !req->file)
1787 req->file = io_file_get_normal(req, req->cqe.fd);
1788 if (!cdef->prep_async)
1790 if (WARN_ON_ONCE(req_has_async_data(req)))
1792 if (!def->manual_alloc) {
1793 if (io_alloc_async_data(req))
1796 return cdef->prep_async(req);
1799 static u32 io_get_sequence(struct io_kiocb *req)
1801 u32 seq = req->ctx->cached_sq_head;
1802 struct io_kiocb *cur;
1804 /* need original cached_sq_head, but it was increased for each req */
1805 io_for_each_link(cur, req)
1810 static __cold void io_drain_req(struct io_kiocb *req)
1811 __must_hold(&ctx->uring_lock)
1813 struct io_ring_ctx *ctx = req->ctx;
1814 struct io_defer_entry *de;
1816 u32 seq = io_get_sequence(req);
1818 /* Still need defer if there is pending req in defer list. */
1819 spin_lock(&ctx->completion_lock);
1820 if (!req_need_defer(req, seq) && list_empty_careful(&ctx->defer_list)) {
1821 spin_unlock(&ctx->completion_lock);
1823 ctx->drain_active = false;
1824 io_req_task_queue(req);
1827 spin_unlock(&ctx->completion_lock);
1829 io_prep_async_link(req);
1830 de = kmalloc(sizeof(*de), GFP_KERNEL);
1833 io_req_defer_failed(req, ret);
1837 spin_lock(&ctx->completion_lock);
1838 if (!req_need_defer(req, seq) && list_empty(&ctx->defer_list)) {
1839 spin_unlock(&ctx->completion_lock);
1844 trace_io_uring_defer(req);
1847 list_add_tail(&de->list, &ctx->defer_list);
1848 spin_unlock(&ctx->completion_lock);
1851 static void io_clean_op(struct io_kiocb *req)
1853 if (req->flags & REQ_F_BUFFER_SELECTED) {
1854 spin_lock(&req->ctx->completion_lock);
1855 io_put_kbuf_comp(req);
1856 spin_unlock(&req->ctx->completion_lock);
1859 if (req->flags & REQ_F_NEED_CLEANUP) {
1860 const struct io_cold_def *def = &io_cold_defs[req->opcode];
1865 if ((req->flags & REQ_F_POLLED) && req->apoll) {
1866 kfree(req->apoll->double_poll);
1870 if (req->flags & REQ_F_INFLIGHT) {
1871 struct io_uring_task *tctx = req->task->io_uring;
1873 atomic_dec(&tctx->inflight_tracked);
1875 if (req->flags & REQ_F_CREDS)
1876 put_cred(req->creds);
1877 if (req->flags & REQ_F_ASYNC_DATA) {
1878 kfree(req->async_data);
1879 req->async_data = NULL;
1881 req->flags &= ~IO_REQ_CLEAN_FLAGS;
1884 static bool io_assign_file(struct io_kiocb *req, const struct io_issue_def *def,
1885 unsigned int issue_flags)
1887 if (req->file || !def->needs_file)
1890 if (req->flags & REQ_F_FIXED_FILE)
1891 req->file = io_file_get_fixed(req, req->cqe.fd, issue_flags);
1893 req->file = io_file_get_normal(req, req->cqe.fd);
1898 static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
1900 const struct io_issue_def *def = &io_issue_defs[req->opcode];
1901 const struct cred *creds = NULL;
1904 if (unlikely(!io_assign_file(req, def, issue_flags)))
1907 if (unlikely((req->flags & REQ_F_CREDS) && req->creds != current_cred()))
1908 creds = override_creds(req->creds);
1910 if (!def->audit_skip)
1911 audit_uring_entry(req->opcode);
1913 ret = def->issue(req, issue_flags);
1915 if (!def->audit_skip)
1916 audit_uring_exit(!ret, ret);
1919 revert_creds(creds);
1921 if (ret == IOU_OK) {
1922 if (issue_flags & IO_URING_F_COMPLETE_DEFER)
1923 io_req_complete_defer(req);
1925 io_req_complete_post(req, issue_flags);
1926 } else if (ret != IOU_ISSUE_SKIP_COMPLETE)
1929 /* If the op doesn't have a file, we're not polling for it */
1930 if ((req->ctx->flags & IORING_SETUP_IOPOLL) && def->iopoll_queue)
1931 io_iopoll_req_issued(req, issue_flags);
1936 int io_poll_issue(struct io_kiocb *req, bool *locked)
1938 io_tw_lock(req->ctx, locked);
1939 return io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_MULTISHOT|
1940 IO_URING_F_COMPLETE_DEFER);
1943 struct io_wq_work *io_wq_free_work(struct io_wq_work *work)
1945 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
1947 req = io_put_req_find_next(req);
1948 return req ? &req->work : NULL;
1951 void io_wq_submit_work(struct io_wq_work *work)
1953 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
1954 const struct io_issue_def *def = &io_issue_defs[req->opcode];
1955 unsigned int issue_flags = IO_URING_F_UNLOCKED | IO_URING_F_IOWQ;
1956 bool needs_poll = false;
1957 int ret = 0, err = -ECANCELED;
1959 /* one will be dropped by ->io_wq_free_work() after returning to io-wq */
1960 if (!(req->flags & REQ_F_REFCOUNT))
1961 __io_req_set_refcount(req, 2);
1965 io_arm_ltimeout(req);
1967 /* either cancelled or io-wq is dying, so don't touch tctx->iowq */
1968 if (work->flags & IO_WQ_WORK_CANCEL) {
1970 io_req_task_queue_fail(req, err);
1973 if (!io_assign_file(req, def, issue_flags)) {
1975 work->flags |= IO_WQ_WORK_CANCEL;
1979 if (req->flags & REQ_F_FORCE_ASYNC) {
1980 bool opcode_poll = def->pollin || def->pollout;
1982 if (opcode_poll && file_can_poll(req->file)) {
1984 issue_flags |= IO_URING_F_NONBLOCK;
1989 ret = io_issue_sqe(req, issue_flags);
1993 * We can get EAGAIN for iopolled IO even though we're
1994 * forcing a sync submission from here, since we can't
1995 * wait for request slots on the block side.
1998 if (!(req->ctx->flags & IORING_SETUP_IOPOLL))
2004 if (io_arm_poll_handler(req, issue_flags) == IO_APOLL_OK)
2006 /* aborted or ready, in either case retry blocking */
2008 issue_flags &= ~IO_URING_F_NONBLOCK;
2011 /* avoid locking problems by failing it from a clean context */
2013 io_req_task_queue_fail(req, ret);
2016 inline struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
2017 unsigned int issue_flags)
2019 struct io_ring_ctx *ctx = req->ctx;
2020 struct file *file = NULL;
2021 unsigned long file_ptr;
2023 io_ring_submit_lock(ctx, issue_flags);
2025 if (unlikely((unsigned int)fd >= ctx->nr_user_files))
2027 fd = array_index_nospec(fd, ctx->nr_user_files);
2028 file_ptr = io_fixed_file_slot(&ctx->file_table, fd)->file_ptr;
2029 file = (struct file *) (file_ptr & FFS_MASK);
2030 file_ptr &= ~FFS_MASK;
2031 /* mask in overlapping REQ_F and FFS bits */
2032 req->flags |= (file_ptr << REQ_F_SUPPORT_NOWAIT_BIT);
2033 io_req_set_rsrc_node(req, ctx, 0);
2035 io_ring_submit_unlock(ctx, issue_flags);
2039 struct file *io_file_get_normal(struct io_kiocb *req, int fd)
2041 struct file *file = fget(fd);
2043 trace_io_uring_file_get(req, fd);
2045 /* we don't allow fixed io_uring files */
2046 if (file && io_is_uring_fops(file))
2047 io_req_track_inflight(req);
2051 static void io_queue_async(struct io_kiocb *req, int ret)
2052 __must_hold(&req->ctx->uring_lock)
2054 struct io_kiocb *linked_timeout;
2056 if (ret != -EAGAIN || (req->flags & REQ_F_NOWAIT)) {
2057 io_req_defer_failed(req, ret);
2061 linked_timeout = io_prep_linked_timeout(req);
2063 switch (io_arm_poll_handler(req, 0)) {
2064 case IO_APOLL_READY:
2065 io_kbuf_recycle(req, 0);
2066 io_req_task_queue(req);
2068 case IO_APOLL_ABORTED:
2069 io_kbuf_recycle(req, 0);
2070 io_queue_iowq(req, NULL);
2077 io_queue_linked_timeout(linked_timeout);
2080 static inline void io_queue_sqe(struct io_kiocb *req)
2081 __must_hold(&req->ctx->uring_lock)
2085 ret = io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_COMPLETE_DEFER);
2088 * We async punt it if the file wasn't marked NOWAIT, or if the file
2089 * doesn't support non-blocking read/write attempts
2092 io_arm_ltimeout(req);
2094 io_queue_async(req, ret);
2097 static void io_queue_sqe_fallback(struct io_kiocb *req)
2098 __must_hold(&req->ctx->uring_lock)
2100 if (unlikely(req->flags & REQ_F_FAIL)) {
2102 * We don't submit, fail them all, for that replace hardlinks
2103 * with normal links. Extra REQ_F_LINK is tolerated.
2105 req->flags &= ~REQ_F_HARDLINK;
2106 req->flags |= REQ_F_LINK;
2107 io_req_defer_failed(req, req->cqe.res);
2109 int ret = io_req_prep_async(req);
2111 if (unlikely(ret)) {
2112 io_req_defer_failed(req, ret);
2116 if (unlikely(req->ctx->drain_active))
2119 io_queue_iowq(req, NULL);
2124 * Check SQE restrictions (opcode and flags).
2126 * Returns 'true' if SQE is allowed, 'false' otherwise.
2128 static inline bool io_check_restriction(struct io_ring_ctx *ctx,
2129 struct io_kiocb *req,
2130 unsigned int sqe_flags)
2132 if (!test_bit(req->opcode, ctx->restrictions.sqe_op))
2135 if ((sqe_flags & ctx->restrictions.sqe_flags_required) !=
2136 ctx->restrictions.sqe_flags_required)
2139 if (sqe_flags & ~(ctx->restrictions.sqe_flags_allowed |
2140 ctx->restrictions.sqe_flags_required))
2146 static void io_init_req_drain(struct io_kiocb *req)
2148 struct io_ring_ctx *ctx = req->ctx;
2149 struct io_kiocb *head = ctx->submit_state.link.head;
2151 ctx->drain_active = true;
2154 * If we need to drain a request in the middle of a link, drain
2155 * the head request and the next request/link after the current
2156 * link. Considering sequential execution of links,
2157 * REQ_F_IO_DRAIN will be maintained for every request of our
2160 head->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC;
2161 ctx->drain_next = true;
2165 static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
2166 const struct io_uring_sqe *sqe)
2167 __must_hold(&ctx->uring_lock)
2169 const struct io_issue_def *def;
2170 unsigned int sqe_flags;
2174 /* req is partially pre-initialised, see io_preinit_req() */
2175 req->opcode = opcode = READ_ONCE(sqe->opcode);
2176 /* same numerical values with corresponding REQ_F_*, safe to copy */
2177 req->flags = sqe_flags = READ_ONCE(sqe->flags);
2178 req->cqe.user_data = READ_ONCE(sqe->user_data);
2180 req->rsrc_node = NULL;
2181 req->task = current;
2183 if (unlikely(opcode >= IORING_OP_LAST)) {
2187 def = &io_issue_defs[opcode];
2188 if (unlikely(sqe_flags & ~SQE_COMMON_FLAGS)) {
2189 /* enforce forwards compatibility on users */
2190 if (sqe_flags & ~SQE_VALID_FLAGS)
2192 if (sqe_flags & IOSQE_BUFFER_SELECT) {
2193 if (!def->buffer_select)
2195 req->buf_index = READ_ONCE(sqe->buf_group);
2197 if (sqe_flags & IOSQE_CQE_SKIP_SUCCESS)
2198 ctx->drain_disabled = true;
2199 if (sqe_flags & IOSQE_IO_DRAIN) {
2200 if (ctx->drain_disabled)
2202 io_init_req_drain(req);
2205 if (unlikely(ctx->restricted || ctx->drain_active || ctx->drain_next)) {
2206 if (ctx->restricted && !io_check_restriction(ctx, req, sqe_flags))
2208 /* knock it to the slow queue path, will be drained there */
2209 if (ctx->drain_active)
2210 req->flags |= REQ_F_FORCE_ASYNC;
2211 /* if there is no link, we're at "next" request and need to drain */
2212 if (unlikely(ctx->drain_next) && !ctx->submit_state.link.head) {
2213 ctx->drain_next = false;
2214 ctx->drain_active = true;
2215 req->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC;
2219 if (!def->ioprio && sqe->ioprio)
2221 if (!def->iopoll && (ctx->flags & IORING_SETUP_IOPOLL))
2224 if (def->needs_file) {
2225 struct io_submit_state *state = &ctx->submit_state;
2227 req->cqe.fd = READ_ONCE(sqe->fd);
2230 * Plug now if we have more than 2 IO left after this, and the
2231 * target is potentially a read/write to block based storage.
2233 if (state->need_plug && def->plug) {
2234 state->plug_started = true;
2235 state->need_plug = false;
2236 blk_start_plug_nr_ios(&state->plug, state->submit_nr);
2240 personality = READ_ONCE(sqe->personality);
2244 req->creds = xa_load(&ctx->personalities, personality);
2247 get_cred(req->creds);
2248 ret = security_uring_override_creds(req->creds);
2250 put_cred(req->creds);
2253 req->flags |= REQ_F_CREDS;
2256 return def->prep(req, sqe);
2259 static __cold int io_submit_fail_init(const struct io_uring_sqe *sqe,
2260 struct io_kiocb *req, int ret)
2262 struct io_ring_ctx *ctx = req->ctx;
2263 struct io_submit_link *link = &ctx->submit_state.link;
2264 struct io_kiocb *head = link->head;
2266 trace_io_uring_req_failed(sqe, req, ret);
2269 * Avoid breaking links in the middle as it renders links with SQPOLL
2270 * unusable. Instead of failing eagerly, continue assembling the link if
2271 * applicable and mark the head with REQ_F_FAIL. The link flushing code
2272 * should find the flag and handle the rest.
2274 req_fail_link_node(req, ret);
2275 if (head && !(head->flags & REQ_F_FAIL))
2276 req_fail_link_node(head, -ECANCELED);
2278 if (!(req->flags & IO_REQ_LINK_FLAGS)) {
2280 link->last->link = req;
2284 io_queue_sqe_fallback(req);
2289 link->last->link = req;
2296 static inline int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
2297 const struct io_uring_sqe *sqe)
2298 __must_hold(&ctx->uring_lock)
2300 struct io_submit_link *link = &ctx->submit_state.link;
2303 ret = io_init_req(ctx, req, sqe);
2305 return io_submit_fail_init(sqe, req, ret);
2307 /* don't need @sqe from now on */
2308 trace_io_uring_submit_sqe(req, true);
2311 * If we already have a head request, queue this one for async
2312 * submittal once the head completes. If we don't have a head but
2313 * IOSQE_IO_LINK is set in the sqe, start a new head. This one will be
2314 * submitted sync once the chain is complete. If none of those
2315 * conditions are true (normal request), then just queue it.
2317 if (unlikely(link->head)) {
2318 ret = io_req_prep_async(req);
2320 return io_submit_fail_init(sqe, req, ret);
2322 trace_io_uring_link(req, link->head);
2323 link->last->link = req;
2326 if (req->flags & IO_REQ_LINK_FLAGS)
2328 /* last request of the link, flush it */
2331 if (req->flags & (REQ_F_FORCE_ASYNC | REQ_F_FAIL))
2334 } else if (unlikely(req->flags & (IO_REQ_LINK_FLAGS |
2335 REQ_F_FORCE_ASYNC | REQ_F_FAIL))) {
2336 if (req->flags & IO_REQ_LINK_FLAGS) {
2341 io_queue_sqe_fallback(req);
2351 * Batched submission is done, ensure local IO is flushed out.
2353 static void io_submit_state_end(struct io_ring_ctx *ctx)
2355 struct io_submit_state *state = &ctx->submit_state;
2357 if (unlikely(state->link.head))
2358 io_queue_sqe_fallback(state->link.head);
2359 /* flush only after queuing links as they can generate completions */
2360 io_submit_flush_completions(ctx);
2361 if (state->plug_started)
2362 blk_finish_plug(&state->plug);
2366 * Start submission side cache.
2368 static void io_submit_state_start(struct io_submit_state *state,
2369 unsigned int max_ios)
2371 state->plug_started = false;
2372 state->need_plug = max_ios > 2;
2373 state->submit_nr = max_ios;
2374 /* set only head, no need to init link_last in advance */
2375 state->link.head = NULL;
2378 static void io_commit_sqring(struct io_ring_ctx *ctx)
2380 struct io_rings *rings = ctx->rings;
2383 * Ensure any loads from the SQEs are done at this point,
2384 * since once we write the new head, the application could
2385 * write new data to them.
2387 smp_store_release(&rings->sq.head, ctx->cached_sq_head);
2391 * Fetch an sqe, if one is available. Note this returns a pointer to memory
2392 * that is mapped by userspace. This means that care needs to be taken to
2393 * ensure that reads are stable, as we cannot rely on userspace always
2394 * being a good citizen. If members of the sqe are validated and then later
2395 * used, it's important that those reads are done through READ_ONCE() to
2396 * prevent a re-load down the line.
2398 static bool io_get_sqe(struct io_ring_ctx *ctx, const struct io_uring_sqe **sqe)
2400 unsigned head, mask = ctx->sq_entries - 1;
2401 unsigned sq_idx = ctx->cached_sq_head++ & mask;
2404 * The cached sq head (or cq tail) serves two purposes:
2406 * 1) allows us to batch the cost of updating the user visible
2408 * 2) allows the kernel side to track the head on its own, even
2409 * though the application is the one updating it.
2411 head = READ_ONCE(ctx->sq_array[sq_idx]);
2412 if (likely(head < ctx->sq_entries)) {
2413 /* double index for 128-byte SQEs, twice as long */
2414 if (ctx->flags & IORING_SETUP_SQE128)
2416 *sqe = &ctx->sq_sqes[head];
2420 /* drop invalid entries */
2422 WRITE_ONCE(ctx->rings->sq_dropped,
2423 READ_ONCE(ctx->rings->sq_dropped) + 1);
2427 int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr)
2428 __must_hold(&ctx->uring_lock)
2430 unsigned int entries = io_sqring_entries(ctx);
2434 if (unlikely(!entries))
2436 /* make sure SQ entry isn't read before tail */
2437 ret = left = min3(nr, ctx->sq_entries, entries);
2438 io_get_task_refs(left);
2439 io_submit_state_start(&ctx->submit_state, left);
2442 const struct io_uring_sqe *sqe;
2443 struct io_kiocb *req;
2445 if (unlikely(!io_alloc_req(ctx, &req)))
2447 if (unlikely(!io_get_sqe(ctx, &sqe))) {
2448 io_req_add_to_cache(req, ctx);
2453 * Continue submitting even for sqe failure if the
2454 * ring was setup with IORING_SETUP_SUBMIT_ALL
2456 if (unlikely(io_submit_sqe(ctx, req, sqe)) &&
2457 !(ctx->flags & IORING_SETUP_SUBMIT_ALL)) {
2463 if (unlikely(left)) {
2465 /* try again if it submitted nothing and can't allocate a req */
2466 if (!ret && io_req_cache_empty(ctx))
2468 current->io_uring->cached_refs += left;
2471 io_submit_state_end(ctx);
2472 /* Commit SQ ring head once we've consumed and submitted all SQEs */
2473 io_commit_sqring(ctx);
2477 struct io_wait_queue {
2478 struct wait_queue_entry wq;
2479 struct io_ring_ctx *ctx;
2481 unsigned nr_timeouts;
2485 static inline bool io_has_work(struct io_ring_ctx *ctx)
2487 return test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq) ||
2488 !llist_empty(&ctx->work_llist);
2491 static inline bool io_should_wake(struct io_wait_queue *iowq)
2493 struct io_ring_ctx *ctx = iowq->ctx;
2494 int dist = READ_ONCE(ctx->rings->cq.tail) - (int) iowq->cq_tail;
2497 * Wake up if we have enough events, or if a timeout occurred since we
2498 * started waiting. For timeouts, we always want to return to userspace,
2499 * regardless of event count.
2501 return dist >= 0 || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
2504 static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode,
2505 int wake_flags, void *key)
2507 struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue, wq);
2510 * Cannot safely flush overflowed CQEs from here, ensure we wake up
2511 * the task, and the next invocation will do it.
2513 if (io_should_wake(iowq) || io_has_work(iowq->ctx))
2514 return autoremove_wake_function(curr, mode, wake_flags, key);
2518 int io_run_task_work_sig(struct io_ring_ctx *ctx)
2520 if (!llist_empty(&ctx->work_llist)) {
2521 __set_current_state(TASK_RUNNING);
2522 if (io_run_local_work(ctx) > 0)
2525 if (io_run_task_work() > 0)
2527 if (task_sigpending(current))
2532 /* when returns >0, the caller should retry */
2533 static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,
2534 struct io_wait_queue *iowq)
2536 if (unlikely(READ_ONCE(ctx->check_cq)))
2538 if (unlikely(!llist_empty(&ctx->work_llist)))
2540 if (unlikely(test_thread_flag(TIF_NOTIFY_SIGNAL)))
2542 if (unlikely(task_sigpending(current)))
2544 if (unlikely(io_should_wake(iowq)))
2546 if (iowq->timeout == KTIME_MAX)
2548 else if (!schedule_hrtimeout(&iowq->timeout, HRTIMER_MODE_ABS))
2554 * Wait until events become available, if we don't already have some. The
2555 * application must reap them itself, as they reside on the shared cq ring.
2557 static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
2558 const sigset_t __user *sig, size_t sigsz,
2559 struct __kernel_timespec __user *uts)
2561 struct io_wait_queue iowq;
2562 struct io_rings *rings = ctx->rings;
2565 if (!io_allowed_run_tw(ctx))
2567 if (!llist_empty(&ctx->work_llist))
2568 io_run_local_work(ctx);
2570 io_cqring_overflow_flush(ctx);
2571 /* if user messes with these they will just get an early return */
2572 if (__io_cqring_events_user(ctx) >= min_events)
2576 #ifdef CONFIG_COMPAT
2577 if (in_compat_syscall())
2578 ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig,
2582 ret = set_user_sigmask(sig, sigsz);
2588 init_waitqueue_func_entry(&iowq.wq, io_wake_function);
2589 iowq.wq.private = current;
2590 INIT_LIST_HEAD(&iowq.wq.entry);
2592 iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts);
2593 iowq.cq_tail = READ_ONCE(ctx->rings->cq.head) + min_events;
2594 iowq.timeout = KTIME_MAX;
2597 struct timespec64 ts;
2599 if (get_timespec64(&ts, uts))
2601 iowq.timeout = ktime_add_ns(timespec64_to_ktime(ts), ktime_get_ns());
2604 trace_io_uring_cqring_wait(ctx, min_events);
2606 unsigned long check_cq;
2608 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
2609 WRITE_ONCE(ctx->cq_waiting, 1);
2610 set_current_state(TASK_INTERRUPTIBLE);
2612 prepare_to_wait_exclusive(&ctx->cq_wait, &iowq.wq,
2613 TASK_INTERRUPTIBLE);
2616 ret = io_cqring_wait_schedule(ctx, &iowq);
2617 __set_current_state(TASK_RUNNING);
2618 WRITE_ONCE(ctx->cq_waiting, 0);
2623 * Run task_work after scheduling and before io_should_wake().
2624 * If we got woken because of task_work being processed, run it
2625 * now rather than let the caller do another wait loop.
2628 if (!llist_empty(&ctx->work_llist))
2629 io_run_local_work(ctx);
2631 check_cq = READ_ONCE(ctx->check_cq);
2632 if (unlikely(check_cq)) {
2633 /* let the caller flush overflows, retry */
2634 if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
2635 io_cqring_do_overflow_flush(ctx);
2636 if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT)) {
2642 if (io_should_wake(&iowq)) {
2649 if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN))
2650 finish_wait(&ctx->cq_wait, &iowq.wq);
2651 restore_saved_sigmask_unless(ret == -EINTR);
2653 return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0;
2656 static void io_mem_free(void *ptr)
2663 page = virt_to_head_page(ptr);
2664 if (put_page_testzero(page))
2665 free_compound_page(page);
2668 static void *io_mem_alloc(size_t size)
2670 gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP;
2672 return (void *) __get_free_pages(gfp, get_order(size));
2675 static unsigned long rings_size(struct io_ring_ctx *ctx, unsigned int sq_entries,
2676 unsigned int cq_entries, size_t *sq_offset)
2678 struct io_rings *rings;
2679 size_t off, sq_array_size;
2681 off = struct_size(rings, cqes, cq_entries);
2682 if (off == SIZE_MAX)
2684 if (ctx->flags & IORING_SETUP_CQE32) {
2685 if (check_shl_overflow(off, 1, &off))
2690 off = ALIGN(off, SMP_CACHE_BYTES);
2698 sq_array_size = array_size(sizeof(u32), sq_entries);
2699 if (sq_array_size == SIZE_MAX)
2702 if (check_add_overflow(off, sq_array_size, &off))
2708 static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg,
2709 unsigned int eventfd_async)
2711 struct io_ev_fd *ev_fd;
2712 __s32 __user *fds = arg;
2715 ev_fd = rcu_dereference_protected(ctx->io_ev_fd,
2716 lockdep_is_held(&ctx->uring_lock));
2720 if (copy_from_user(&fd, fds, sizeof(*fds)))
2723 ev_fd = kmalloc(sizeof(*ev_fd), GFP_KERNEL);
2727 ev_fd->cq_ev_fd = eventfd_ctx_fdget(fd);
2728 if (IS_ERR(ev_fd->cq_ev_fd)) {
2729 int ret = PTR_ERR(ev_fd->cq_ev_fd);
2734 spin_lock(&ctx->completion_lock);
2735 ctx->evfd_last_cq_tail = ctx->cached_cq_tail;
2736 spin_unlock(&ctx->completion_lock);
2738 ev_fd->eventfd_async = eventfd_async;
2739 ctx->has_evfd = true;
2740 rcu_assign_pointer(ctx->io_ev_fd, ev_fd);
2741 atomic_set(&ev_fd->refs, 1);
2742 atomic_set(&ev_fd->ops, 0);
2746 static int io_eventfd_unregister(struct io_ring_ctx *ctx)
2748 struct io_ev_fd *ev_fd;
2750 ev_fd = rcu_dereference_protected(ctx->io_ev_fd,
2751 lockdep_is_held(&ctx->uring_lock));
2753 ctx->has_evfd = false;
2754 rcu_assign_pointer(ctx->io_ev_fd, NULL);
2755 if (!atomic_fetch_or(BIT(IO_EVENTFD_OP_FREE_BIT), &ev_fd->ops))
2756 call_rcu(&ev_fd->rcu, io_eventfd_ops);
2763 static void io_req_caches_free(struct io_ring_ctx *ctx)
2765 struct io_kiocb *req;
2768 mutex_lock(&ctx->uring_lock);
2769 io_flush_cached_locked_reqs(ctx, &ctx->submit_state);
2771 while (!io_req_cache_empty(ctx)) {
2772 req = io_extract_req(ctx);
2773 kmem_cache_free(req_cachep, req);
2777 percpu_ref_put_many(&ctx->refs, nr);
2778 mutex_unlock(&ctx->uring_lock);
2781 static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
2783 io_sq_thread_finish(ctx);
2784 io_rsrc_refs_drop(ctx);
2785 /* __io_rsrc_put_work() may need uring_lock to progress, wait w/o it */
2786 io_wait_rsrc_data(ctx->buf_data);
2787 io_wait_rsrc_data(ctx->file_data);
2789 mutex_lock(&ctx->uring_lock);
2791 __io_sqe_buffers_unregister(ctx);
2793 __io_sqe_files_unregister(ctx);
2794 io_cqring_overflow_kill(ctx);
2795 io_eventfd_unregister(ctx);
2796 io_alloc_cache_free(&ctx->apoll_cache, io_apoll_cache_free);
2797 io_alloc_cache_free(&ctx->netmsg_cache, io_netmsg_cache_free);
2798 mutex_unlock(&ctx->uring_lock);
2799 io_destroy_buffers(ctx);
2801 put_cred(ctx->sq_creds);
2802 if (ctx->submitter_task)
2803 put_task_struct(ctx->submitter_task);
2805 /* there are no registered resources left, nobody uses it */
2807 io_rsrc_node_destroy(ctx->rsrc_node);
2808 if (ctx->rsrc_backup_node)
2809 io_rsrc_node_destroy(ctx->rsrc_backup_node);
2810 flush_delayed_work(&ctx->rsrc_put_work);
2811 flush_delayed_work(&ctx->fallback_work);
2813 WARN_ON_ONCE(!list_empty(&ctx->rsrc_ref_list));
2814 WARN_ON_ONCE(!llist_empty(&ctx->rsrc_put_llist));
2816 #if defined(CONFIG_UNIX)
2817 if (ctx->ring_sock) {
2818 ctx->ring_sock->file = NULL; /* so that iput() is called */
2819 sock_release(ctx->ring_sock);
2822 WARN_ON_ONCE(!list_empty(&ctx->ltimeout_list));
2824 if (ctx->mm_account) {
2825 mmdrop(ctx->mm_account);
2826 ctx->mm_account = NULL;
2828 io_mem_free(ctx->rings);
2829 io_mem_free(ctx->sq_sqes);
2831 percpu_ref_exit(&ctx->refs);
2832 free_uid(ctx->user);
2833 io_req_caches_free(ctx);
2835 io_wq_put_hash(ctx->hash_map);
2836 kfree(ctx->cancel_table.hbs);
2837 kfree(ctx->cancel_table_locked.hbs);
2838 kfree(ctx->dummy_ubuf);
2840 xa_destroy(&ctx->io_bl_xa);
2844 static __cold void io_activate_pollwq_cb(struct callback_head *cb)
2846 struct io_ring_ctx *ctx = container_of(cb, struct io_ring_ctx,
2849 mutex_lock(&ctx->uring_lock);
2850 ctx->poll_activated = true;
2851 mutex_unlock(&ctx->uring_lock);
2854 * Wake ups for some events between start of polling and activation
2855 * might've been lost due to loose synchronisation.
2857 wake_up_all(&ctx->poll_wq);
2858 percpu_ref_put(&ctx->refs);
2861 static __cold void io_activate_pollwq(struct io_ring_ctx *ctx)
2863 spin_lock(&ctx->completion_lock);
2864 /* already activated or in progress */
2865 if (ctx->poll_activated || ctx->poll_wq_task_work.func)
2867 if (WARN_ON_ONCE(!ctx->task_complete))
2869 if (!ctx->submitter_task)
2872 * with ->submitter_task only the submitter task completes requests, we
2873 * only need to sync with it, which is done by injecting a tw
2875 init_task_work(&ctx->poll_wq_task_work, io_activate_pollwq_cb);
2876 percpu_ref_get(&ctx->refs);
2877 if (task_work_add(ctx->submitter_task, &ctx->poll_wq_task_work, TWA_SIGNAL))
2878 percpu_ref_put(&ctx->refs);
2880 spin_unlock(&ctx->completion_lock);
2883 static __poll_t io_uring_poll(struct file *file, poll_table *wait)
2885 struct io_ring_ctx *ctx = file->private_data;
2888 if (unlikely(!ctx->poll_activated))
2889 io_activate_pollwq(ctx);
2891 poll_wait(file, &ctx->poll_wq, wait);
2893 * synchronizes with barrier from wq_has_sleeper call in
2897 if (!io_sqring_full(ctx))
2898 mask |= EPOLLOUT | EPOLLWRNORM;
2901 * Don't flush cqring overflow list here, just do a simple check.
2902 * Otherwise there could possible be ABBA deadlock:
2905 * lock(&ctx->uring_lock);
2907 * lock(&ctx->uring_lock);
2910 * Users may get EPOLLIN meanwhile seeing nothing in cqring, this
2911 * pushes them to do the flush.
2914 if (__io_cqring_events_user(ctx) || io_has_work(ctx))
2915 mask |= EPOLLIN | EPOLLRDNORM;
2920 static int io_unregister_personality(struct io_ring_ctx *ctx, unsigned id)
2922 const struct cred *creds;
2924 creds = xa_erase(&ctx->personalities, id);
2933 struct io_tctx_exit {
2934 struct callback_head task_work;
2935 struct completion completion;
2936 struct io_ring_ctx *ctx;
2939 static __cold void io_tctx_exit_cb(struct callback_head *cb)
2941 struct io_uring_task *tctx = current->io_uring;
2942 struct io_tctx_exit *work;
2944 work = container_of(cb, struct io_tctx_exit, task_work);
2946 * When @in_cancel, we're in cancellation and it's racy to remove the
2947 * node. It'll be removed by the end of cancellation, just ignore it.
2948 * tctx can be NULL if the queueing of this task_work raced with
2949 * work cancelation off the exec path.
2951 if (tctx && !atomic_read(&tctx->in_cancel))
2952 io_uring_del_tctx_node((unsigned long)work->ctx);
2953 complete(&work->completion);
2956 static __cold bool io_cancel_ctx_cb(struct io_wq_work *work, void *data)
2958 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
2960 return req->ctx == data;
2963 static __cold void io_ring_exit_work(struct work_struct *work)
2965 struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx, exit_work);
2966 unsigned long timeout = jiffies + HZ * 60 * 5;
2967 unsigned long interval = HZ / 20;
2968 struct io_tctx_exit exit;
2969 struct io_tctx_node *node;
2973 * If we're doing polled IO and end up having requests being
2974 * submitted async (out-of-line), then completions can come in while
2975 * we're waiting for refs to drop. We need to reap these manually,
2976 * as nobody else will be looking for them.
2979 if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq)) {
2980 mutex_lock(&ctx->uring_lock);
2981 io_cqring_overflow_kill(ctx);
2982 mutex_unlock(&ctx->uring_lock);
2985 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
2986 io_move_task_work_from_local(ctx);
2988 while (io_uring_try_cancel_requests(ctx, NULL, true))
2992 struct io_sq_data *sqd = ctx->sq_data;
2993 struct task_struct *tsk;
2995 io_sq_thread_park(sqd);
2997 if (tsk && tsk->io_uring && tsk->io_uring->io_wq)
2998 io_wq_cancel_cb(tsk->io_uring->io_wq,
2999 io_cancel_ctx_cb, ctx, true);
3000 io_sq_thread_unpark(sqd);
3003 io_req_caches_free(ctx);
3005 if (WARN_ON_ONCE(time_after(jiffies, timeout))) {
3006 /* there is little hope left, don't run it too often */
3009 } while (!wait_for_completion_timeout(&ctx->ref_comp, interval));
3011 init_completion(&exit.completion);
3012 init_task_work(&exit.task_work, io_tctx_exit_cb);
3015 * Some may use context even when all refs and requests have been put,
3016 * and they are free to do so while still holding uring_lock or
3017 * completion_lock, see io_req_task_submit(). Apart from other work,
3018 * this lock/unlock section also waits them to finish.
3020 mutex_lock(&ctx->uring_lock);
3021 while (!list_empty(&ctx->tctx_list)) {
3022 WARN_ON_ONCE(time_after(jiffies, timeout));
3024 node = list_first_entry(&ctx->tctx_list, struct io_tctx_node,
3026 /* don't spin on a single task if cancellation failed */
3027 list_rotate_left(&ctx->tctx_list);
3028 ret = task_work_add(node->task, &exit.task_work, TWA_SIGNAL);
3029 if (WARN_ON_ONCE(ret))
3032 mutex_unlock(&ctx->uring_lock);
3033 wait_for_completion(&exit.completion);
3034 mutex_lock(&ctx->uring_lock);
3036 mutex_unlock(&ctx->uring_lock);
3037 spin_lock(&ctx->completion_lock);
3038 spin_unlock(&ctx->completion_lock);
3040 io_ring_ctx_free(ctx);
3043 static __cold void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
3045 unsigned long index;
3046 struct creds *creds;
3048 mutex_lock(&ctx->uring_lock);
3049 percpu_ref_kill(&ctx->refs);
3050 xa_for_each(&ctx->personalities, index, creds)
3051 io_unregister_personality(ctx, index);
3053 io_poll_remove_all(ctx, NULL, true);
3054 mutex_unlock(&ctx->uring_lock);
3057 * If we failed setting up the ctx, we might not have any rings
3058 * and therefore did not submit any requests
3061 io_kill_timeouts(ctx, NULL, true);
3063 INIT_WORK(&ctx->exit_work, io_ring_exit_work);
3065 * Use system_unbound_wq to avoid spawning tons of event kworkers
3066 * if we're exiting a ton of rings at the same time. It just adds
3067 * noise and overhead, there's no discernable change in runtime
3068 * over using system_wq.
3070 queue_work(system_unbound_wq, &ctx->exit_work);
3073 static int io_uring_release(struct inode *inode, struct file *file)
3075 struct io_ring_ctx *ctx = file->private_data;
3077 file->private_data = NULL;
3078 io_ring_ctx_wait_and_kill(ctx);
3082 struct io_task_cancel {
3083 struct task_struct *task;
3087 static bool io_cancel_task_cb(struct io_wq_work *work, void *data)
3089 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
3090 struct io_task_cancel *cancel = data;
3092 return io_match_task_safe(req, cancel->task, cancel->all);
3095 static __cold bool io_cancel_defer_files(struct io_ring_ctx *ctx,
3096 struct task_struct *task,
3099 struct io_defer_entry *de;
3102 spin_lock(&ctx->completion_lock);
3103 list_for_each_entry_reverse(de, &ctx->defer_list, list) {
3104 if (io_match_task_safe(de->req, task, cancel_all)) {
3105 list_cut_position(&list, &ctx->defer_list, &de->list);
3109 spin_unlock(&ctx->completion_lock);
3110 if (list_empty(&list))
3113 while (!list_empty(&list)) {
3114 de = list_first_entry(&list, struct io_defer_entry, list);
3115 list_del_init(&de->list);
3116 io_req_task_queue_fail(de->req, -ECANCELED);
3122 static __cold bool io_uring_try_cancel_iowq(struct io_ring_ctx *ctx)
3124 struct io_tctx_node *node;
3125 enum io_wq_cancel cret;
3128 mutex_lock(&ctx->uring_lock);
3129 list_for_each_entry(node, &ctx->tctx_list, ctx_node) {
3130 struct io_uring_task *tctx = node->task->io_uring;
3133 * io_wq will stay alive while we hold uring_lock, because it's
3134 * killed after ctx nodes, which requires to take the lock.
3136 if (!tctx || !tctx->io_wq)
3138 cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_ctx_cb, ctx, true);
3139 ret |= (cret != IO_WQ_CANCEL_NOTFOUND);
3141 mutex_unlock(&ctx->uring_lock);
3146 static __cold bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
3147 struct task_struct *task,
3150 struct io_task_cancel cancel = { .task = task, .all = cancel_all, };
3151 struct io_uring_task *tctx = task ? task->io_uring : NULL;
3152 enum io_wq_cancel cret;
3155 /* failed during ring init, it couldn't have issued any requests */
3160 ret |= io_uring_try_cancel_iowq(ctx);
3161 } else if (tctx && tctx->io_wq) {
3163 * Cancels requests of all rings, not only @ctx, but
3164 * it's fine as the task is in exit/exec.
3166 cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_task_cb,
3168 ret |= (cret != IO_WQ_CANCEL_NOTFOUND);
3171 /* SQPOLL thread does its own polling */
3172 if ((!(ctx->flags & IORING_SETUP_SQPOLL) && cancel_all) ||
3173 (ctx->sq_data && ctx->sq_data->thread == current)) {
3174 while (!wq_list_empty(&ctx->iopoll_list)) {
3175 io_iopoll_try_reap_events(ctx);
3181 if ((ctx->flags & IORING_SETUP_DEFER_TASKRUN) &&
3182 io_allowed_defer_tw_run(ctx))
3183 ret |= io_run_local_work(ctx) > 0;
3184 ret |= io_cancel_defer_files(ctx, task, cancel_all);
3185 mutex_lock(&ctx->uring_lock);
3186 ret |= io_poll_remove_all(ctx, task, cancel_all);
3187 mutex_unlock(&ctx->uring_lock);
3188 ret |= io_kill_timeouts(ctx, task, cancel_all);
3190 ret |= io_run_task_work() > 0;
3194 static s64 tctx_inflight(struct io_uring_task *tctx, bool tracked)
3197 return atomic_read(&tctx->inflight_tracked);
3198 return percpu_counter_sum(&tctx->inflight);
3202 * Find any io_uring ctx that this task has registered or done IO on, and cancel
3203 * requests. @sqd should be not-null IFF it's an SQPOLL thread cancellation.
3205 __cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd)
3207 struct io_uring_task *tctx = current->io_uring;
3208 struct io_ring_ctx *ctx;
3212 WARN_ON_ONCE(sqd && sqd->thread != current);
3214 if (!current->io_uring)
3217 io_wq_exit_start(tctx->io_wq);
3219 atomic_inc(&tctx->in_cancel);
3223 io_uring_drop_tctx_refs(current);
3224 /* read completions before cancelations */
3225 inflight = tctx_inflight(tctx, !cancel_all);
3230 struct io_tctx_node *node;
3231 unsigned long index;
3233 xa_for_each(&tctx->xa, index, node) {
3234 /* sqpoll task will cancel all its requests */
3235 if (node->ctx->sq_data)
3237 loop |= io_uring_try_cancel_requests(node->ctx,
3238 current, cancel_all);
3241 list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
3242 loop |= io_uring_try_cancel_requests(ctx,
3252 prepare_to_wait(&tctx->wait, &wait, TASK_INTERRUPTIBLE);
3254 io_uring_drop_tctx_refs(current);
3257 * If we've seen completions, retry without waiting. This
3258 * avoids a race where a completion comes in before we did
3259 * prepare_to_wait().
3261 if (inflight == tctx_inflight(tctx, !cancel_all))
3263 finish_wait(&tctx->wait, &wait);
3266 io_uring_clean_tctx(tctx);
3269 * We shouldn't run task_works after cancel, so just leave
3270 * ->in_cancel set for normal exit.
3272 atomic_dec(&tctx->in_cancel);
3273 /* for exec all current's requests should be gone, kill tctx */
3274 __io_uring_free(current);
3278 void __io_uring_cancel(bool cancel_all)
3280 io_uring_cancel_generic(cancel_all, NULL);
3283 static void *io_uring_validate_mmap_request(struct file *file,
3284 loff_t pgoff, size_t sz)
3286 struct io_ring_ctx *ctx = file->private_data;
3287 loff_t offset = pgoff << PAGE_SHIFT;
3292 case IORING_OFF_SQ_RING:
3293 case IORING_OFF_CQ_RING:
3296 case IORING_OFF_SQES:
3300 return ERR_PTR(-EINVAL);
3303 page = virt_to_head_page(ptr);
3304 if (sz > page_size(page))
3305 return ERR_PTR(-EINVAL);
3312 static __cold int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
3314 size_t sz = vma->vm_end - vma->vm_start;
3318 ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz);
3320 return PTR_ERR(ptr);
3322 pfn = virt_to_phys(ptr) >> PAGE_SHIFT;
3323 return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot);
3326 #else /* !CONFIG_MMU */
3328 static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
3330 return is_nommu_shared_mapping(vma->vm_flags) ? 0 : -EINVAL;
3333 static unsigned int io_uring_nommu_mmap_capabilities(struct file *file)
3335 return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE;
3338 static unsigned long io_uring_nommu_get_unmapped_area(struct file *file,
3339 unsigned long addr, unsigned long len,
3340 unsigned long pgoff, unsigned long flags)
3344 ptr = io_uring_validate_mmap_request(file, pgoff, len);
3346 return PTR_ERR(ptr);
3348 return (unsigned long) ptr;
3351 #endif /* !CONFIG_MMU */
3353 static int io_validate_ext_arg(unsigned flags, const void __user *argp, size_t argsz)
3355 if (flags & IORING_ENTER_EXT_ARG) {
3356 struct io_uring_getevents_arg arg;
3358 if (argsz != sizeof(arg))
3360 if (copy_from_user(&arg, argp, sizeof(arg)))
3366 static int io_get_ext_arg(unsigned flags, const void __user *argp, size_t *argsz,
3367 struct __kernel_timespec __user **ts,
3368 const sigset_t __user **sig)
3370 struct io_uring_getevents_arg arg;
3373 * If EXT_ARG isn't set, then we have no timespec and the argp pointer
3374 * is just a pointer to the sigset_t.
3376 if (!(flags & IORING_ENTER_EXT_ARG)) {
3377 *sig = (const sigset_t __user *) argp;
3383 * EXT_ARG is set - ensure we agree on the size of it and copy in our
3384 * timespec and sigset_t pointers if good.
3386 if (*argsz != sizeof(arg))
3388 if (copy_from_user(&arg, argp, sizeof(arg)))
3392 *sig = u64_to_user_ptr(arg.sigmask);
3393 *argsz = arg.sigmask_sz;
3394 *ts = u64_to_user_ptr(arg.ts);
3398 SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
3399 u32, min_complete, u32, flags, const void __user *, argp,
3402 struct io_ring_ctx *ctx;
3406 if (unlikely(flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP |
3407 IORING_ENTER_SQ_WAIT | IORING_ENTER_EXT_ARG |
3408 IORING_ENTER_REGISTERED_RING)))
3412 * Ring fd has been registered via IORING_REGISTER_RING_FDS, we
3413 * need only dereference our task private array to find it.
3415 if (flags & IORING_ENTER_REGISTERED_RING) {
3416 struct io_uring_task *tctx = current->io_uring;
3418 if (unlikely(!tctx || fd >= IO_RINGFD_REG_MAX))
3420 fd = array_index_nospec(fd, IO_RINGFD_REG_MAX);
3421 f.file = tctx->registered_rings[fd];
3423 if (unlikely(!f.file))
3427 if (unlikely(!f.file))
3430 if (unlikely(!io_is_uring_fops(f.file)))
3434 ctx = f.file->private_data;
3436 if (unlikely(ctx->flags & IORING_SETUP_R_DISABLED))
3440 * For SQ polling, the thread will do all submissions and completions.
3441 * Just return the requested submit count, and wake the thread if
3445 if (ctx->flags & IORING_SETUP_SQPOLL) {
3446 io_cqring_overflow_flush(ctx);
3448 if (unlikely(ctx->sq_data->thread == NULL)) {
3452 if (flags & IORING_ENTER_SQ_WAKEUP)
3453 wake_up(&ctx->sq_data->wait);
3454 if (flags & IORING_ENTER_SQ_WAIT)
3455 io_sqpoll_wait_sq(ctx);
3458 } else if (to_submit) {
3459 ret = io_uring_add_tctx_node(ctx);
3463 mutex_lock(&ctx->uring_lock);
3464 ret = io_submit_sqes(ctx, to_submit);
3465 if (ret != to_submit) {
3466 mutex_unlock(&ctx->uring_lock);
3469 if (flags & IORING_ENTER_GETEVENTS) {
3470 if (ctx->syscall_iopoll)
3473 * Ignore errors, we'll soon call io_cqring_wait() and
3474 * it should handle ownership problems if any.
3476 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
3477 (void)io_run_local_work_locked(ctx);
3479 mutex_unlock(&ctx->uring_lock);
3482 if (flags & IORING_ENTER_GETEVENTS) {
3485 if (ctx->syscall_iopoll) {
3487 * We disallow the app entering submit/complete with
3488 * polling, but we still need to lock the ring to
3489 * prevent racing with polled issue that got punted to
3492 mutex_lock(&ctx->uring_lock);
3494 ret2 = io_validate_ext_arg(flags, argp, argsz);
3495 if (likely(!ret2)) {
3496 min_complete = min(min_complete,
3498 ret2 = io_iopoll_check(ctx, min_complete);
3500 mutex_unlock(&ctx->uring_lock);
3502 const sigset_t __user *sig;
3503 struct __kernel_timespec __user *ts;
3505 ret2 = io_get_ext_arg(flags, argp, &argsz, &ts, &sig);
3506 if (likely(!ret2)) {
3507 min_complete = min(min_complete,
3509 ret2 = io_cqring_wait(ctx, min_complete, sig,
3518 * EBADR indicates that one or more CQE were dropped.
3519 * Once the user has been informed we can clear the bit
3520 * as they are obviously ok with those drops.
3522 if (unlikely(ret2 == -EBADR))
3523 clear_bit(IO_CHECK_CQ_DROPPED_BIT,
3532 static const struct file_operations io_uring_fops = {
3533 .release = io_uring_release,
3534 .mmap = io_uring_mmap,
3536 .get_unmapped_area = io_uring_nommu_get_unmapped_area,
3537 .mmap_capabilities = io_uring_nommu_mmap_capabilities,
3539 .poll = io_uring_poll,
3540 #ifdef CONFIG_PROC_FS
3541 .show_fdinfo = io_uring_show_fdinfo,
3545 bool io_is_uring_fops(struct file *file)
3547 return file->f_op == &io_uring_fops;
3550 static __cold int io_allocate_scq_urings(struct io_ring_ctx *ctx,
3551 struct io_uring_params *p)
3553 struct io_rings *rings;
3554 size_t size, sq_array_offset;
3556 /* make sure these are sane, as we already accounted them */
3557 ctx->sq_entries = p->sq_entries;
3558 ctx->cq_entries = p->cq_entries;
3560 size = rings_size(ctx, p->sq_entries, p->cq_entries, &sq_array_offset);
3561 if (size == SIZE_MAX)
3564 rings = io_mem_alloc(size);
3569 ctx->sq_array = (u32 *)((char *)rings + sq_array_offset);
3570 rings->sq_ring_mask = p->sq_entries - 1;
3571 rings->cq_ring_mask = p->cq_entries - 1;
3572 rings->sq_ring_entries = p->sq_entries;
3573 rings->cq_ring_entries = p->cq_entries;
3575 if (p->flags & IORING_SETUP_SQE128)
3576 size = array_size(2 * sizeof(struct io_uring_sqe), p->sq_entries);
3578 size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
3579 if (size == SIZE_MAX) {
3580 io_mem_free(ctx->rings);
3585 ctx->sq_sqes = io_mem_alloc(size);
3586 if (!ctx->sq_sqes) {
3587 io_mem_free(ctx->rings);
3595 static int io_uring_install_fd(struct io_ring_ctx *ctx, struct file *file)
3599 fd = get_unused_fd_flags(O_RDWR | O_CLOEXEC);
3603 ret = __io_uring_add_tctx_node(ctx);
3608 fd_install(fd, file);
3613 * Allocate an anonymous fd, this is what constitutes the application
3614 * visible backing of an io_uring instance. The application mmaps this
3615 * fd to gain access to the SQ/CQ ring details. If UNIX sockets are enabled,
3616 * we have to tie this fd to a socket for file garbage collection purposes.
3618 static struct file *io_uring_get_file(struct io_ring_ctx *ctx)
3621 #if defined(CONFIG_UNIX)
3624 ret = sock_create_kern(&init_net, PF_UNIX, SOCK_RAW, IPPROTO_IP,
3627 return ERR_PTR(ret);
3630 file = anon_inode_getfile_secure("[io_uring]", &io_uring_fops, ctx,
3631 O_RDWR | O_CLOEXEC, NULL);
3632 #if defined(CONFIG_UNIX)
3634 sock_release(ctx->ring_sock);
3635 ctx->ring_sock = NULL;
3637 ctx->ring_sock->file = file;
3643 static __cold int io_uring_create(unsigned entries, struct io_uring_params *p,
3644 struct io_uring_params __user *params)
3646 struct io_ring_ctx *ctx;
3652 if (entries > IORING_MAX_ENTRIES) {
3653 if (!(p->flags & IORING_SETUP_CLAMP))
3655 entries = IORING_MAX_ENTRIES;
3659 * Use twice as many entries for the CQ ring. It's possible for the
3660 * application to drive a higher depth than the size of the SQ ring,
3661 * since the sqes are only used at submission time. This allows for
3662 * some flexibility in overcommitting a bit. If the application has
3663 * set IORING_SETUP_CQSIZE, it will have passed in the desired number
3664 * of CQ ring entries manually.
3666 p->sq_entries = roundup_pow_of_two(entries);
3667 if (p->flags & IORING_SETUP_CQSIZE) {
3669 * If IORING_SETUP_CQSIZE is set, we do the same roundup
3670 * to a power-of-two, if it isn't already. We do NOT impose
3671 * any cq vs sq ring sizing.
3675 if (p->cq_entries > IORING_MAX_CQ_ENTRIES) {
3676 if (!(p->flags & IORING_SETUP_CLAMP))
3678 p->cq_entries = IORING_MAX_CQ_ENTRIES;
3680 p->cq_entries = roundup_pow_of_two(p->cq_entries);
3681 if (p->cq_entries < p->sq_entries)
3684 p->cq_entries = 2 * p->sq_entries;
3687 ctx = io_ring_ctx_alloc(p);
3691 if ((ctx->flags & IORING_SETUP_DEFER_TASKRUN) &&
3692 !(ctx->flags & IORING_SETUP_IOPOLL) &&
3693 !(ctx->flags & IORING_SETUP_SQPOLL))
3694 ctx->task_complete = true;
3697 * lazy poll_wq activation relies on ->task_complete for synchronisation
3698 * purposes, see io_activate_pollwq()
3700 if (!ctx->task_complete)
3701 ctx->poll_activated = true;
3704 * When SETUP_IOPOLL and SETUP_SQPOLL are both enabled, user
3705 * space applications don't need to do io completion events
3706 * polling again, they can rely on io_sq_thread to do polling
3707 * work, which can reduce cpu usage and uring_lock contention.
3709 if (ctx->flags & IORING_SETUP_IOPOLL &&
3710 !(ctx->flags & IORING_SETUP_SQPOLL))
3711 ctx->syscall_iopoll = 1;
3713 ctx->compat = in_compat_syscall();
3714 if (!capable(CAP_IPC_LOCK))
3715 ctx->user = get_uid(current_user());
3718 * For SQPOLL, we just need a wakeup, always. For !SQPOLL, if
3719 * COOP_TASKRUN is set, then IPIs are never needed by the app.
3722 if (ctx->flags & IORING_SETUP_SQPOLL) {
3723 /* IPI related flags don't make sense with SQPOLL */
3724 if (ctx->flags & (IORING_SETUP_COOP_TASKRUN |
3725 IORING_SETUP_TASKRUN_FLAG |
3726 IORING_SETUP_DEFER_TASKRUN))
3728 ctx->notify_method = TWA_SIGNAL_NO_IPI;
3729 } else if (ctx->flags & IORING_SETUP_COOP_TASKRUN) {
3730 ctx->notify_method = TWA_SIGNAL_NO_IPI;
3732 if (ctx->flags & IORING_SETUP_TASKRUN_FLAG &&
3733 !(ctx->flags & IORING_SETUP_DEFER_TASKRUN))
3735 ctx->notify_method = TWA_SIGNAL;
3739 * For DEFER_TASKRUN we require the completion task to be the same as the
3740 * submission task. This implies that there is only one submitter, so enforce
3743 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN &&
3744 !(ctx->flags & IORING_SETUP_SINGLE_ISSUER)) {
3749 * This is just grabbed for accounting purposes. When a process exits,
3750 * the mm is exited and dropped before the files, hence we need to hang
3751 * on to this mm purely for the purposes of being able to unaccount
3752 * memory (locked/pinned vm). It's not used for anything else.
3754 mmgrab(current->mm);
3755 ctx->mm_account = current->mm;
3757 ret = io_allocate_scq_urings(ctx, p);
3761 ret = io_sq_offload_create(ctx, p);
3764 /* always set a rsrc node */
3765 ret = io_rsrc_node_switch_start(ctx);
3768 io_rsrc_node_switch(ctx, NULL);
3770 memset(&p->sq_off, 0, sizeof(p->sq_off));
3771 p->sq_off.head = offsetof(struct io_rings, sq.head);
3772 p->sq_off.tail = offsetof(struct io_rings, sq.tail);
3773 p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask);
3774 p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries);
3775 p->sq_off.flags = offsetof(struct io_rings, sq_flags);
3776 p->sq_off.dropped = offsetof(struct io_rings, sq_dropped);
3777 p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings;
3779 memset(&p->cq_off, 0, sizeof(p->cq_off));
3780 p->cq_off.head = offsetof(struct io_rings, cq.head);
3781 p->cq_off.tail = offsetof(struct io_rings, cq.tail);
3782 p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask);
3783 p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries);
3784 p->cq_off.overflow = offsetof(struct io_rings, cq_overflow);
3785 p->cq_off.cqes = offsetof(struct io_rings, cqes);
3786 p->cq_off.flags = offsetof(struct io_rings, cq_flags);
3788 p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP |
3789 IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS |
3790 IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL |
3791 IORING_FEAT_POLL_32BITS | IORING_FEAT_SQPOLL_NONFIXED |
3792 IORING_FEAT_EXT_ARG | IORING_FEAT_NATIVE_WORKERS |
3793 IORING_FEAT_RSRC_TAGS | IORING_FEAT_CQE_SKIP |
3794 IORING_FEAT_LINKED_FILE | IORING_FEAT_REG_REG_RING;
3796 if (copy_to_user(params, p, sizeof(*p))) {
3801 if (ctx->flags & IORING_SETUP_SINGLE_ISSUER
3802 && !(ctx->flags & IORING_SETUP_R_DISABLED))
3803 WRITE_ONCE(ctx->submitter_task, get_task_struct(current));
3805 file = io_uring_get_file(ctx);
3807 ret = PTR_ERR(file);
3812 * Install ring fd as the very last thing, so we don't risk someone
3813 * having closed it before we finish setup
3815 ret = io_uring_install_fd(ctx, file);
3817 /* fput will clean it up */
3822 trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags);
3825 io_ring_ctx_wait_and_kill(ctx);
3830 * Sets up an aio uring context, and returns the fd. Applications asks for a
3831 * ring size, we return the actual sq/cq ring sizes (among other things) in the
3832 * params structure passed in.
3834 static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
3836 struct io_uring_params p;
3839 if (copy_from_user(&p, params, sizeof(p)))
3841 for (i = 0; i < ARRAY_SIZE(p.resv); i++) {
3846 if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL |
3847 IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE |
3848 IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ |
3849 IORING_SETUP_R_DISABLED | IORING_SETUP_SUBMIT_ALL |
3850 IORING_SETUP_COOP_TASKRUN | IORING_SETUP_TASKRUN_FLAG |
3851 IORING_SETUP_SQE128 | IORING_SETUP_CQE32 |
3852 IORING_SETUP_SINGLE_ISSUER | IORING_SETUP_DEFER_TASKRUN))
3855 return io_uring_create(entries, &p, params);
3858 SYSCALL_DEFINE2(io_uring_setup, u32, entries,
3859 struct io_uring_params __user *, params)
3861 return io_uring_setup(entries, params);
3864 static __cold int io_probe(struct io_ring_ctx *ctx, void __user *arg,
3867 struct io_uring_probe *p;
3871 size = struct_size(p, ops, nr_args);
3872 if (size == SIZE_MAX)
3874 p = kzalloc(size, GFP_KERNEL);
3879 if (copy_from_user(p, arg, size))
3882 if (memchr_inv(p, 0, size))
3885 p->last_op = IORING_OP_LAST - 1;
3886 if (nr_args > IORING_OP_LAST)
3887 nr_args = IORING_OP_LAST;
3889 for (i = 0; i < nr_args; i++) {
3891 if (!io_issue_defs[i].not_supported)
3892 p->ops[i].flags = IO_URING_OP_SUPPORTED;
3897 if (copy_to_user(arg, p, size))
3904 static int io_register_personality(struct io_ring_ctx *ctx)
3906 const struct cred *creds;
3910 creds = get_current_cred();
3912 ret = xa_alloc_cyclic(&ctx->personalities, &id, (void *)creds,
3913 XA_LIMIT(0, USHRT_MAX), &ctx->pers_next, GFP_KERNEL);
3921 static __cold int io_register_restrictions(struct io_ring_ctx *ctx,
3922 void __user *arg, unsigned int nr_args)
3924 struct io_uring_restriction *res;
3928 /* Restrictions allowed only if rings started disabled */
3929 if (!(ctx->flags & IORING_SETUP_R_DISABLED))
3932 /* We allow only a single restrictions registration */
3933 if (ctx->restrictions.registered)
3936 if (!arg || nr_args > IORING_MAX_RESTRICTIONS)
3939 size = array_size(nr_args, sizeof(*res));
3940 if (size == SIZE_MAX)
3943 res = memdup_user(arg, size);
3945 return PTR_ERR(res);
3949 for (i = 0; i < nr_args; i++) {
3950 switch (res[i].opcode) {
3951 case IORING_RESTRICTION_REGISTER_OP:
3952 if (res[i].register_op >= IORING_REGISTER_LAST) {
3957 __set_bit(res[i].register_op,
3958 ctx->restrictions.register_op);
3960 case IORING_RESTRICTION_SQE_OP:
3961 if (res[i].sqe_op >= IORING_OP_LAST) {
3966 __set_bit(res[i].sqe_op, ctx->restrictions.sqe_op);
3968 case IORING_RESTRICTION_SQE_FLAGS_ALLOWED:
3969 ctx->restrictions.sqe_flags_allowed = res[i].sqe_flags;
3971 case IORING_RESTRICTION_SQE_FLAGS_REQUIRED:
3972 ctx->restrictions.sqe_flags_required = res[i].sqe_flags;
3981 /* Reset all restrictions if an error happened */
3983 memset(&ctx->restrictions, 0, sizeof(ctx->restrictions));
3985 ctx->restrictions.registered = true;
3991 static int io_register_enable_rings(struct io_ring_ctx *ctx)
3993 if (!(ctx->flags & IORING_SETUP_R_DISABLED))
3996 if (ctx->flags & IORING_SETUP_SINGLE_ISSUER && !ctx->submitter_task) {
3997 WRITE_ONCE(ctx->submitter_task, get_task_struct(current));
3999 * Lazy activation attempts would fail if it was polled before
4000 * submitter_task is set.
4002 if (wq_has_sleeper(&ctx->poll_wq))
4003 io_activate_pollwq(ctx);
4006 if (ctx->restrictions.registered)
4007 ctx->restricted = 1;
4009 ctx->flags &= ~IORING_SETUP_R_DISABLED;
4010 if (ctx->sq_data && wq_has_sleeper(&ctx->sq_data->wait))
4011 wake_up(&ctx->sq_data->wait);
4015 static __cold int io_register_iowq_aff(struct io_ring_ctx *ctx,
4016 void __user *arg, unsigned len)
4018 struct io_uring_task *tctx = current->io_uring;
4019 cpumask_var_t new_mask;
4022 if (!tctx || !tctx->io_wq)
4025 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
4028 cpumask_clear(new_mask);
4029 if (len > cpumask_size())
4030 len = cpumask_size();
4032 if (in_compat_syscall()) {
4033 ret = compat_get_bitmap(cpumask_bits(new_mask),
4034 (const compat_ulong_t __user *)arg,
4035 len * 8 /* CHAR_BIT */);
4037 ret = copy_from_user(new_mask, arg, len);
4041 free_cpumask_var(new_mask);
4045 ret = io_wq_cpu_affinity(tctx->io_wq, new_mask);
4046 free_cpumask_var(new_mask);
4050 static __cold int io_unregister_iowq_aff(struct io_ring_ctx *ctx)
4052 struct io_uring_task *tctx = current->io_uring;
4054 if (!tctx || !tctx->io_wq)
4057 return io_wq_cpu_affinity(tctx->io_wq, NULL);
4060 static __cold int io_register_iowq_max_workers(struct io_ring_ctx *ctx,
4062 __must_hold(&ctx->uring_lock)
4064 struct io_tctx_node *node;
4065 struct io_uring_task *tctx = NULL;
4066 struct io_sq_data *sqd = NULL;
4070 if (copy_from_user(new_count, arg, sizeof(new_count)))
4072 for (i = 0; i < ARRAY_SIZE(new_count); i++)
4073 if (new_count[i] > INT_MAX)
4076 if (ctx->flags & IORING_SETUP_SQPOLL) {
4080 * Observe the correct sqd->lock -> ctx->uring_lock
4081 * ordering. Fine to drop uring_lock here, we hold
4084 refcount_inc(&sqd->refs);
4085 mutex_unlock(&ctx->uring_lock);
4086 mutex_lock(&sqd->lock);
4087 mutex_lock(&ctx->uring_lock);
4089 tctx = sqd->thread->io_uring;
4092 tctx = current->io_uring;
4095 BUILD_BUG_ON(sizeof(new_count) != sizeof(ctx->iowq_limits));
4097 for (i = 0; i < ARRAY_SIZE(new_count); i++)
4099 ctx->iowq_limits[i] = new_count[i];
4100 ctx->iowq_limits_set = true;
4102 if (tctx && tctx->io_wq) {
4103 ret = io_wq_max_workers(tctx->io_wq, new_count);
4107 memset(new_count, 0, sizeof(new_count));
4111 mutex_unlock(&sqd->lock);
4112 io_put_sq_data(sqd);
4115 if (copy_to_user(arg, new_count, sizeof(new_count)))
4118 /* that's it for SQPOLL, only the SQPOLL task creates requests */
4122 /* now propagate the restriction to all registered users */
4123 list_for_each_entry(node, &ctx->tctx_list, ctx_node) {
4124 struct io_uring_task *tctx = node->task->io_uring;
4126 if (WARN_ON_ONCE(!tctx->io_wq))
4129 for (i = 0; i < ARRAY_SIZE(new_count); i++)
4130 new_count[i] = ctx->iowq_limits[i];
4131 /* ignore errors, it always returns zero anyway */
4132 (void)io_wq_max_workers(tctx->io_wq, new_count);
4137 mutex_unlock(&sqd->lock);
4138 io_put_sq_data(sqd);
4143 static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
4144 void __user *arg, unsigned nr_args)
4145 __releases(ctx->uring_lock)
4146 __acquires(ctx->uring_lock)
4151 * We don't quiesce the refs for register anymore and so it can't be
4152 * dying as we're holding a file ref here.
4154 if (WARN_ON_ONCE(percpu_ref_is_dying(&ctx->refs)))
4157 if (ctx->submitter_task && ctx->submitter_task != current)
4160 if (ctx->restricted) {
4161 opcode = array_index_nospec(opcode, IORING_REGISTER_LAST);
4162 if (!test_bit(opcode, ctx->restrictions.register_op))
4167 case IORING_REGISTER_BUFFERS:
4171 ret = io_sqe_buffers_register(ctx, arg, nr_args, NULL);
4173 case IORING_UNREGISTER_BUFFERS:
4177 ret = io_sqe_buffers_unregister(ctx);
4179 case IORING_REGISTER_FILES:
4183 ret = io_sqe_files_register(ctx, arg, nr_args, NULL);
4185 case IORING_UNREGISTER_FILES:
4189 ret = io_sqe_files_unregister(ctx);
4191 case IORING_REGISTER_FILES_UPDATE:
4192 ret = io_register_files_update(ctx, arg, nr_args);
4194 case IORING_REGISTER_EVENTFD:
4198 ret = io_eventfd_register(ctx, arg, 0);
4200 case IORING_REGISTER_EVENTFD_ASYNC:
4204 ret = io_eventfd_register(ctx, arg, 1);
4206 case IORING_UNREGISTER_EVENTFD:
4210 ret = io_eventfd_unregister(ctx);
4212 case IORING_REGISTER_PROBE:
4214 if (!arg || nr_args > 256)
4216 ret = io_probe(ctx, arg, nr_args);
4218 case IORING_REGISTER_PERSONALITY:
4222 ret = io_register_personality(ctx);
4224 case IORING_UNREGISTER_PERSONALITY:
4228 ret = io_unregister_personality(ctx, nr_args);
4230 case IORING_REGISTER_ENABLE_RINGS:
4234 ret = io_register_enable_rings(ctx);
4236 case IORING_REGISTER_RESTRICTIONS:
4237 ret = io_register_restrictions(ctx, arg, nr_args);
4239 case IORING_REGISTER_FILES2:
4240 ret = io_register_rsrc(ctx, arg, nr_args, IORING_RSRC_FILE);
4242 case IORING_REGISTER_FILES_UPDATE2:
4243 ret = io_register_rsrc_update(ctx, arg, nr_args,
4246 case IORING_REGISTER_BUFFERS2:
4247 ret = io_register_rsrc(ctx, arg, nr_args, IORING_RSRC_BUFFER);
4249 case IORING_REGISTER_BUFFERS_UPDATE:
4250 ret = io_register_rsrc_update(ctx, arg, nr_args,
4251 IORING_RSRC_BUFFER);
4253 case IORING_REGISTER_IOWQ_AFF:
4255 if (!arg || !nr_args)
4257 ret = io_register_iowq_aff(ctx, arg, nr_args);
4259 case IORING_UNREGISTER_IOWQ_AFF:
4263 ret = io_unregister_iowq_aff(ctx);
4265 case IORING_REGISTER_IOWQ_MAX_WORKERS:
4267 if (!arg || nr_args != 2)
4269 ret = io_register_iowq_max_workers(ctx, arg);
4271 case IORING_REGISTER_RING_FDS:
4272 ret = io_ringfd_register(ctx, arg, nr_args);
4274 case IORING_UNREGISTER_RING_FDS:
4275 ret = io_ringfd_unregister(ctx, arg, nr_args);
4277 case IORING_REGISTER_PBUF_RING:
4279 if (!arg || nr_args != 1)
4281 ret = io_register_pbuf_ring(ctx, arg);
4283 case IORING_UNREGISTER_PBUF_RING:
4285 if (!arg || nr_args != 1)
4287 ret = io_unregister_pbuf_ring(ctx, arg);
4289 case IORING_REGISTER_SYNC_CANCEL:
4291 if (!arg || nr_args != 1)
4293 ret = io_sync_cancel(ctx, arg);
4295 case IORING_REGISTER_FILE_ALLOC_RANGE:
4297 if (!arg || nr_args)
4299 ret = io_register_file_alloc_range(ctx, arg);
4309 SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode,
4310 void __user *, arg, unsigned int, nr_args)
4312 struct io_ring_ctx *ctx;
4315 bool use_registered_ring;
4317 use_registered_ring = !!(opcode & IORING_REGISTER_USE_REGISTERED_RING);
4318 opcode &= ~IORING_REGISTER_USE_REGISTERED_RING;
4320 if (opcode >= IORING_REGISTER_LAST)
4323 if (use_registered_ring) {
4325 * Ring fd has been registered via IORING_REGISTER_RING_FDS, we
4326 * need only dereference our task private array to find it.
4328 struct io_uring_task *tctx = current->io_uring;
4330 if (unlikely(!tctx || fd >= IO_RINGFD_REG_MAX))
4332 fd = array_index_nospec(fd, IO_RINGFD_REG_MAX);
4333 f.file = tctx->registered_rings[fd];
4335 if (unlikely(!f.file))
4339 if (unlikely(!f.file))
4342 if (!io_is_uring_fops(f.file))
4346 ctx = f.file->private_data;
4348 mutex_lock(&ctx->uring_lock);
4349 ret = __io_uring_register(ctx, opcode, arg, nr_args);
4350 mutex_unlock(&ctx->uring_lock);
4351 trace_io_uring_register(ctx, opcode, ctx->nr_user_files, ctx->nr_user_bufs, ret);
4357 static int __init io_uring_init(void)
4359 #define __BUILD_BUG_VERIFY_OFFSET_SIZE(stype, eoffset, esize, ename) do { \
4360 BUILD_BUG_ON(offsetof(stype, ename) != eoffset); \
4361 BUILD_BUG_ON(sizeof_field(stype, ename) != esize); \
4364 #define BUILD_BUG_SQE_ELEM(eoffset, etype, ename) \
4365 __BUILD_BUG_VERIFY_OFFSET_SIZE(struct io_uring_sqe, eoffset, sizeof(etype), ename)
4366 #define BUILD_BUG_SQE_ELEM_SIZE(eoffset, esize, ename) \
4367 __BUILD_BUG_VERIFY_OFFSET_SIZE(struct io_uring_sqe, eoffset, esize, ename)
4368 BUILD_BUG_ON(sizeof(struct io_uring_sqe) != 64);
4369 BUILD_BUG_SQE_ELEM(0, __u8, opcode);
4370 BUILD_BUG_SQE_ELEM(1, __u8, flags);
4371 BUILD_BUG_SQE_ELEM(2, __u16, ioprio);
4372 BUILD_BUG_SQE_ELEM(4, __s32, fd);
4373 BUILD_BUG_SQE_ELEM(8, __u64, off);
4374 BUILD_BUG_SQE_ELEM(8, __u64, addr2);
4375 BUILD_BUG_SQE_ELEM(8, __u32, cmd_op);
4376 BUILD_BUG_SQE_ELEM(12, __u32, __pad1);
4377 BUILD_BUG_SQE_ELEM(16, __u64, addr);
4378 BUILD_BUG_SQE_ELEM(16, __u64, splice_off_in);
4379 BUILD_BUG_SQE_ELEM(24, __u32, len);
4380 BUILD_BUG_SQE_ELEM(28, __kernel_rwf_t, rw_flags);
4381 BUILD_BUG_SQE_ELEM(28, /* compat */ int, rw_flags);
4382 BUILD_BUG_SQE_ELEM(28, /* compat */ __u32, rw_flags);
4383 BUILD_BUG_SQE_ELEM(28, __u32, fsync_flags);
4384 BUILD_BUG_SQE_ELEM(28, /* compat */ __u16, poll_events);
4385 BUILD_BUG_SQE_ELEM(28, __u32, poll32_events);
4386 BUILD_BUG_SQE_ELEM(28, __u32, sync_range_flags);
4387 BUILD_BUG_SQE_ELEM(28, __u32, msg_flags);
4388 BUILD_BUG_SQE_ELEM(28, __u32, timeout_flags);
4389 BUILD_BUG_SQE_ELEM(28, __u32, accept_flags);
4390 BUILD_BUG_SQE_ELEM(28, __u32, cancel_flags);
4391 BUILD_BUG_SQE_ELEM(28, __u32, open_flags);
4392 BUILD_BUG_SQE_ELEM(28, __u32, statx_flags);
4393 BUILD_BUG_SQE_ELEM(28, __u32, fadvise_advice);
4394 BUILD_BUG_SQE_ELEM(28, __u32, splice_flags);
4395 BUILD_BUG_SQE_ELEM(28, __u32, rename_flags);
4396 BUILD_BUG_SQE_ELEM(28, __u32, unlink_flags);
4397 BUILD_BUG_SQE_ELEM(28, __u32, hardlink_flags);
4398 BUILD_BUG_SQE_ELEM(28, __u32, xattr_flags);
4399 BUILD_BUG_SQE_ELEM(28, __u32, msg_ring_flags);
4400 BUILD_BUG_SQE_ELEM(32, __u64, user_data);
4401 BUILD_BUG_SQE_ELEM(40, __u16, buf_index);
4402 BUILD_BUG_SQE_ELEM(40, __u16, buf_group);
4403 BUILD_BUG_SQE_ELEM(42, __u16, personality);
4404 BUILD_BUG_SQE_ELEM(44, __s32, splice_fd_in);
4405 BUILD_BUG_SQE_ELEM(44, __u32, file_index);
4406 BUILD_BUG_SQE_ELEM(44, __u16, addr_len);
4407 BUILD_BUG_SQE_ELEM(46, __u16, __pad3[0]);
4408 BUILD_BUG_SQE_ELEM(48, __u64, addr3);
4409 BUILD_BUG_SQE_ELEM_SIZE(48, 0, cmd);
4410 BUILD_BUG_SQE_ELEM(56, __u64, __pad2);
4412 BUILD_BUG_ON(sizeof(struct io_uring_files_update) !=
4413 sizeof(struct io_uring_rsrc_update));
4414 BUILD_BUG_ON(sizeof(struct io_uring_rsrc_update) >
4415 sizeof(struct io_uring_rsrc_update2));
4417 /* ->buf_index is u16 */
4418 BUILD_BUG_ON(offsetof(struct io_uring_buf_ring, bufs) != 0);
4419 BUILD_BUG_ON(offsetof(struct io_uring_buf, resv) !=
4420 offsetof(struct io_uring_buf_ring, tail));
4422 /* should fit into one byte */
4423 BUILD_BUG_ON(SQE_VALID_FLAGS >= (1 << 8));
4424 BUILD_BUG_ON(SQE_COMMON_FLAGS >= (1 << 8));
4425 BUILD_BUG_ON((SQE_VALID_FLAGS | SQE_COMMON_FLAGS) != SQE_VALID_FLAGS);
4427 BUILD_BUG_ON(__REQ_F_LAST_BIT > 8 * sizeof(int));
4429 BUILD_BUG_ON(sizeof(atomic_t) != sizeof(u32));
4431 io_uring_optable_init();
4433 req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC |
4437 __initcall(io_uring_init);