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>
75 #include <asm/shmparam.h>
77 #define CREATE_TRACE_POINTS
78 #include <trace/events/io_uring.h>
80 #include <uapi/linux/io_uring.h>
99 #include "alloc_cache.h"
101 #define IORING_MAX_ENTRIES 32768
102 #define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES)
104 #define IORING_MAX_RESTRICTIONS (IORING_RESTRICTION_LAST + \
105 IORING_REGISTER_LAST + IORING_OP_LAST)
107 #define SQE_COMMON_FLAGS (IOSQE_FIXED_FILE | IOSQE_IO_LINK | \
108 IOSQE_IO_HARDLINK | IOSQE_ASYNC)
110 #define SQE_VALID_FLAGS (SQE_COMMON_FLAGS | IOSQE_BUFFER_SELECT | \
111 IOSQE_IO_DRAIN | IOSQE_CQE_SKIP_SUCCESS)
113 #define IO_REQ_CLEAN_FLAGS (REQ_F_BUFFER_SELECTED | REQ_F_NEED_CLEANUP | \
114 REQ_F_POLLED | REQ_F_INFLIGHT | REQ_F_CREDS | \
117 #define IO_REQ_CLEAN_SLOW_FLAGS (REQ_F_REFCOUNT | REQ_F_LINK | REQ_F_HARDLINK |\
120 #define IO_TCTX_REFS_CACHE_NR (1U << 10)
122 #define IO_COMPL_BATCH 32
123 #define IO_REQ_ALLOC_BATCH 8
126 IO_CHECK_CQ_OVERFLOW_BIT
,
127 IO_CHECK_CQ_DROPPED_BIT
,
131 IO_EVENTFD_OP_SIGNAL_BIT
,
132 IO_EVENTFD_OP_FREE_BIT
,
135 struct io_defer_entry
{
136 struct list_head list
;
137 struct io_kiocb
*req
;
141 /* requests with any of those set should undergo io_disarm_next() */
142 #define IO_DISARM_MASK (REQ_F_ARM_LTIMEOUT | REQ_F_LINK_TIMEOUT | REQ_F_FAIL)
143 #define IO_REQ_LINK_FLAGS (REQ_F_LINK | REQ_F_HARDLINK)
145 static bool io_uring_try_cancel_requests(struct io_ring_ctx
*ctx
,
146 struct task_struct
*task
,
149 static void io_queue_sqe(struct io_kiocb
*req
);
151 struct kmem_cache
*req_cachep
;
153 struct sock
*io_uring_get_socket(struct file
*file
)
155 #if defined(CONFIG_UNIX)
156 if (io_is_uring_fops(file
)) {
157 struct io_ring_ctx
*ctx
= file
->private_data
;
159 return ctx
->ring_sock
->sk
;
164 EXPORT_SYMBOL(io_uring_get_socket
);
166 static inline void io_submit_flush_completions(struct io_ring_ctx
*ctx
)
168 if (!wq_list_empty(&ctx
->submit_state
.compl_reqs
) ||
169 ctx
->submit_state
.cqes_count
)
170 __io_submit_flush_completions(ctx
);
173 static inline unsigned int __io_cqring_events(struct io_ring_ctx
*ctx
)
175 return ctx
->cached_cq_tail
- READ_ONCE(ctx
->rings
->cq
.head
);
178 static inline unsigned int __io_cqring_events_user(struct io_ring_ctx
*ctx
)
180 return READ_ONCE(ctx
->rings
->cq
.tail
) - READ_ONCE(ctx
->rings
->cq
.head
);
183 static bool io_match_linked(struct io_kiocb
*head
)
185 struct io_kiocb
*req
;
187 io_for_each_link(req
, head
) {
188 if (req
->flags
& REQ_F_INFLIGHT
)
195 * As io_match_task() but protected against racing with linked timeouts.
196 * User must not hold timeout_lock.
198 bool io_match_task_safe(struct io_kiocb
*head
, struct task_struct
*task
,
203 if (task
&& head
->task
!= task
)
208 if (head
->flags
& REQ_F_LINK_TIMEOUT
) {
209 struct io_ring_ctx
*ctx
= head
->ctx
;
211 /* protect against races with linked timeouts */
212 spin_lock_irq(&ctx
->timeout_lock
);
213 matched
= io_match_linked(head
);
214 spin_unlock_irq(&ctx
->timeout_lock
);
216 matched
= io_match_linked(head
);
221 static inline void req_fail_link_node(struct io_kiocb
*req
, int res
)
224 io_req_set_res(req
, res
, 0);
227 static inline void io_req_add_to_cache(struct io_kiocb
*req
, struct io_ring_ctx
*ctx
)
229 wq_stack_add_head(&req
->comp_list
, &ctx
->submit_state
.free_list
);
232 static __cold
void io_ring_ctx_ref_free(struct percpu_ref
*ref
)
234 struct io_ring_ctx
*ctx
= container_of(ref
, struct io_ring_ctx
, refs
);
236 complete(&ctx
->ref_comp
);
239 static __cold
void io_fallback_req_func(struct work_struct
*work
)
241 struct io_ring_ctx
*ctx
= container_of(work
, struct io_ring_ctx
,
243 struct llist_node
*node
= llist_del_all(&ctx
->fallback_llist
);
244 struct io_kiocb
*req
, *tmp
;
245 struct io_tw_state ts
= { .locked
= true, };
247 mutex_lock(&ctx
->uring_lock
);
248 llist_for_each_entry_safe(req
, tmp
, node
, io_task_work
.node
)
249 req
->io_task_work
.func(req
, &ts
);
250 if (WARN_ON_ONCE(!ts
.locked
))
252 io_submit_flush_completions(ctx
);
253 mutex_unlock(&ctx
->uring_lock
);
256 static int io_alloc_hash_table(struct io_hash_table
*table
, unsigned bits
)
258 unsigned hash_buckets
= 1U << bits
;
259 size_t hash_size
= hash_buckets
* sizeof(table
->hbs
[0]);
261 table
->hbs
= kmalloc(hash_size
, GFP_KERNEL
);
265 table
->hash_bits
= bits
;
266 init_hash_table(table
, hash_buckets
);
270 static __cold
struct io_ring_ctx
*io_ring_ctx_alloc(struct io_uring_params
*p
)
272 struct io_ring_ctx
*ctx
;
275 ctx
= kzalloc(sizeof(*ctx
), GFP_KERNEL
);
279 xa_init(&ctx
->io_bl_xa
);
282 * Use 5 bits less than the max cq entries, that should give us around
283 * 32 entries per hash list if totally full and uniformly spread, but
284 * don't keep too many buckets to not overconsume memory.
286 hash_bits
= ilog2(p
->cq_entries
) - 5;
287 hash_bits
= clamp(hash_bits
, 1, 8);
288 if (io_alloc_hash_table(&ctx
->cancel_table
, hash_bits
))
290 if (io_alloc_hash_table(&ctx
->cancel_table_locked
, hash_bits
))
292 if (percpu_ref_init(&ctx
->refs
, io_ring_ctx_ref_free
,
296 ctx
->flags
= p
->flags
;
297 init_waitqueue_head(&ctx
->sqo_sq_wait
);
298 INIT_LIST_HEAD(&ctx
->sqd_list
);
299 INIT_LIST_HEAD(&ctx
->cq_overflow_list
);
300 INIT_LIST_HEAD(&ctx
->io_buffers_cache
);
301 io_alloc_cache_init(&ctx
->rsrc_node_cache
, IO_NODE_ALLOC_CACHE_MAX
,
302 sizeof(struct io_rsrc_node
));
303 io_alloc_cache_init(&ctx
->apoll_cache
, IO_ALLOC_CACHE_MAX
,
304 sizeof(struct async_poll
));
305 io_alloc_cache_init(&ctx
->netmsg_cache
, IO_ALLOC_CACHE_MAX
,
306 sizeof(struct io_async_msghdr
));
307 init_completion(&ctx
->ref_comp
);
308 xa_init_flags(&ctx
->personalities
, XA_FLAGS_ALLOC1
);
309 mutex_init(&ctx
->uring_lock
);
310 init_waitqueue_head(&ctx
->cq_wait
);
311 init_waitqueue_head(&ctx
->poll_wq
);
312 init_waitqueue_head(&ctx
->rsrc_quiesce_wq
);
313 spin_lock_init(&ctx
->completion_lock
);
314 spin_lock_init(&ctx
->timeout_lock
);
315 INIT_WQ_LIST(&ctx
->iopoll_list
);
316 INIT_LIST_HEAD(&ctx
->io_buffers_pages
);
317 INIT_LIST_HEAD(&ctx
->io_buffers_comp
);
318 INIT_LIST_HEAD(&ctx
->defer_list
);
319 INIT_LIST_HEAD(&ctx
->timeout_list
);
320 INIT_LIST_HEAD(&ctx
->ltimeout_list
);
321 INIT_LIST_HEAD(&ctx
->rsrc_ref_list
);
322 init_llist_head(&ctx
->work_llist
);
323 INIT_LIST_HEAD(&ctx
->tctx_list
);
324 ctx
->submit_state
.free_list
.next
= NULL
;
325 INIT_WQ_LIST(&ctx
->locked_free_list
);
326 INIT_DELAYED_WORK(&ctx
->fallback_work
, io_fallback_req_func
);
327 INIT_WQ_LIST(&ctx
->submit_state
.compl_reqs
);
330 kfree(ctx
->cancel_table
.hbs
);
331 kfree(ctx
->cancel_table_locked
.hbs
);
333 xa_destroy(&ctx
->io_bl_xa
);
338 static void io_account_cq_overflow(struct io_ring_ctx
*ctx
)
340 struct io_rings
*r
= ctx
->rings
;
342 WRITE_ONCE(r
->cq_overflow
, READ_ONCE(r
->cq_overflow
) + 1);
346 static bool req_need_defer(struct io_kiocb
*req
, u32 seq
)
348 if (unlikely(req
->flags
& REQ_F_IO_DRAIN
)) {
349 struct io_ring_ctx
*ctx
= req
->ctx
;
351 return seq
+ READ_ONCE(ctx
->cq_extra
) != ctx
->cached_cq_tail
;
357 static void io_clean_op(struct io_kiocb
*req
)
359 if (req
->flags
& REQ_F_BUFFER_SELECTED
) {
360 spin_lock(&req
->ctx
->completion_lock
);
361 io_put_kbuf_comp(req
);
362 spin_unlock(&req
->ctx
->completion_lock
);
365 if (req
->flags
& REQ_F_NEED_CLEANUP
) {
366 const struct io_cold_def
*def
= &io_cold_defs
[req
->opcode
];
371 if ((req
->flags
& REQ_F_POLLED
) && req
->apoll
) {
372 kfree(req
->apoll
->double_poll
);
376 if (req
->flags
& REQ_F_INFLIGHT
) {
377 struct io_uring_task
*tctx
= req
->task
->io_uring
;
379 atomic_dec(&tctx
->inflight_tracked
);
381 if (req
->flags
& REQ_F_CREDS
)
382 put_cred(req
->creds
);
383 if (req
->flags
& REQ_F_ASYNC_DATA
) {
384 kfree(req
->async_data
);
385 req
->async_data
= NULL
;
387 req
->flags
&= ~IO_REQ_CLEAN_FLAGS
;
390 static inline void io_req_track_inflight(struct io_kiocb
*req
)
392 if (!(req
->flags
& REQ_F_INFLIGHT
)) {
393 req
->flags
|= REQ_F_INFLIGHT
;
394 atomic_inc(&req
->task
->io_uring
->inflight_tracked
);
398 static struct io_kiocb
*__io_prep_linked_timeout(struct io_kiocb
*req
)
400 if (WARN_ON_ONCE(!req
->link
))
403 req
->flags
&= ~REQ_F_ARM_LTIMEOUT
;
404 req
->flags
|= REQ_F_LINK_TIMEOUT
;
406 /* linked timeouts should have two refs once prep'ed */
407 io_req_set_refcount(req
);
408 __io_req_set_refcount(req
->link
, 2);
412 static inline struct io_kiocb
*io_prep_linked_timeout(struct io_kiocb
*req
)
414 if (likely(!(req
->flags
& REQ_F_ARM_LTIMEOUT
)))
416 return __io_prep_linked_timeout(req
);
419 static noinline
void __io_arm_ltimeout(struct io_kiocb
*req
)
421 io_queue_linked_timeout(__io_prep_linked_timeout(req
));
424 static inline void io_arm_ltimeout(struct io_kiocb
*req
)
426 if (unlikely(req
->flags
& REQ_F_ARM_LTIMEOUT
))
427 __io_arm_ltimeout(req
);
430 static void io_prep_async_work(struct io_kiocb
*req
)
432 const struct io_issue_def
*def
= &io_issue_defs
[req
->opcode
];
433 struct io_ring_ctx
*ctx
= req
->ctx
;
435 if (!(req
->flags
& REQ_F_CREDS
)) {
436 req
->flags
|= REQ_F_CREDS
;
437 req
->creds
= get_current_cred();
440 req
->work
.list
.next
= NULL
;
442 req
->work
.cancel_seq
= atomic_read(&ctx
->cancel_seq
);
443 if (req
->flags
& REQ_F_FORCE_ASYNC
)
444 req
->work
.flags
|= IO_WQ_WORK_CONCURRENT
;
446 if (req
->file
&& !(req
->flags
& REQ_F_FIXED_FILE
))
447 req
->flags
|= io_file_get_flags(req
->file
);
449 if (req
->file
&& (req
->flags
& REQ_F_ISREG
)) {
450 bool should_hash
= def
->hash_reg_file
;
452 /* don't serialize this request if the fs doesn't need it */
453 if (should_hash
&& (req
->file
->f_flags
& O_DIRECT
) &&
454 (req
->file
->f_mode
& FMODE_DIO_PARALLEL_WRITE
))
456 if (should_hash
|| (ctx
->flags
& IORING_SETUP_IOPOLL
))
457 io_wq_hash_work(&req
->work
, file_inode(req
->file
));
458 } else if (!req
->file
|| !S_ISBLK(file_inode(req
->file
)->i_mode
)) {
459 if (def
->unbound_nonreg_file
)
460 req
->work
.flags
|= IO_WQ_WORK_UNBOUND
;
464 static void io_prep_async_link(struct io_kiocb
*req
)
466 struct io_kiocb
*cur
;
468 if (req
->flags
& REQ_F_LINK_TIMEOUT
) {
469 struct io_ring_ctx
*ctx
= req
->ctx
;
471 spin_lock_irq(&ctx
->timeout_lock
);
472 io_for_each_link(cur
, req
)
473 io_prep_async_work(cur
);
474 spin_unlock_irq(&ctx
->timeout_lock
);
476 io_for_each_link(cur
, req
)
477 io_prep_async_work(cur
);
481 void io_queue_iowq(struct io_kiocb
*req
, struct io_tw_state
*ts_dont_use
)
483 struct io_kiocb
*link
= io_prep_linked_timeout(req
);
484 struct io_uring_task
*tctx
= req
->task
->io_uring
;
487 BUG_ON(!tctx
->io_wq
);
489 /* init ->work of the whole link before punting */
490 io_prep_async_link(req
);
493 * Not expected to happen, but if we do have a bug where this _can_
494 * happen, catch it here and ensure the request is marked as
495 * canceled. That will make io-wq go through the usual work cancel
496 * procedure rather than attempt to run this request (or create a new
499 if (WARN_ON_ONCE(!same_thread_group(req
->task
, current
)))
500 req
->work
.flags
|= IO_WQ_WORK_CANCEL
;
502 trace_io_uring_queue_async_work(req
, io_wq_is_hashed(&req
->work
));
503 io_wq_enqueue(tctx
->io_wq
, &req
->work
);
505 io_queue_linked_timeout(link
);
508 static __cold
void io_queue_deferred(struct io_ring_ctx
*ctx
)
510 while (!list_empty(&ctx
->defer_list
)) {
511 struct io_defer_entry
*de
= list_first_entry(&ctx
->defer_list
,
512 struct io_defer_entry
, list
);
514 if (req_need_defer(de
->req
, de
->seq
))
516 list_del_init(&de
->list
);
517 io_req_task_queue(de
->req
);
523 static void io_eventfd_ops(struct rcu_head
*rcu
)
525 struct io_ev_fd
*ev_fd
= container_of(rcu
, struct io_ev_fd
, rcu
);
526 int ops
= atomic_xchg(&ev_fd
->ops
, 0);
528 if (ops
& BIT(IO_EVENTFD_OP_SIGNAL_BIT
))
529 eventfd_signal_mask(ev_fd
->cq_ev_fd
, 1, EPOLL_URING_WAKE
);
531 /* IO_EVENTFD_OP_FREE_BIT may not be set here depending on callback
532 * ordering in a race but if references are 0 we know we have to free
535 if (atomic_dec_and_test(&ev_fd
->refs
)) {
536 eventfd_ctx_put(ev_fd
->cq_ev_fd
);
541 static void io_eventfd_signal(struct io_ring_ctx
*ctx
)
543 struct io_ev_fd
*ev_fd
= NULL
;
547 * rcu_dereference ctx->io_ev_fd once and use it for both for checking
550 ev_fd
= rcu_dereference(ctx
->io_ev_fd
);
553 * Check again if ev_fd exists incase an io_eventfd_unregister call
554 * completed between the NULL check of ctx->io_ev_fd at the start of
555 * the function and rcu_read_lock.
557 if (unlikely(!ev_fd
))
559 if (READ_ONCE(ctx
->rings
->cq_flags
) & IORING_CQ_EVENTFD_DISABLED
)
561 if (ev_fd
->eventfd_async
&& !io_wq_current_is_worker())
564 if (likely(eventfd_signal_allowed())) {
565 eventfd_signal_mask(ev_fd
->cq_ev_fd
, 1, EPOLL_URING_WAKE
);
567 atomic_inc(&ev_fd
->refs
);
568 if (!atomic_fetch_or(BIT(IO_EVENTFD_OP_SIGNAL_BIT
), &ev_fd
->ops
))
569 call_rcu_hurry(&ev_fd
->rcu
, io_eventfd_ops
);
571 atomic_dec(&ev_fd
->refs
);
578 static void io_eventfd_flush_signal(struct io_ring_ctx
*ctx
)
582 spin_lock(&ctx
->completion_lock
);
585 * Eventfd should only get triggered when at least one event has been
586 * posted. Some applications rely on the eventfd notification count
587 * only changing IFF a new CQE has been added to the CQ ring. There's
588 * no depedency on 1:1 relationship between how many times this
589 * function is called (and hence the eventfd count) and number of CQEs
590 * posted to the CQ ring.
592 skip
= ctx
->cached_cq_tail
== ctx
->evfd_last_cq_tail
;
593 ctx
->evfd_last_cq_tail
= ctx
->cached_cq_tail
;
594 spin_unlock(&ctx
->completion_lock
);
598 io_eventfd_signal(ctx
);
601 void __io_commit_cqring_flush(struct io_ring_ctx
*ctx
)
603 if (ctx
->poll_activated
)
604 io_poll_wq_wake(ctx
);
605 if (ctx
->off_timeout_used
)
606 io_flush_timeouts(ctx
);
607 if (ctx
->drain_active
) {
608 spin_lock(&ctx
->completion_lock
);
609 io_queue_deferred(ctx
);
610 spin_unlock(&ctx
->completion_lock
);
613 io_eventfd_flush_signal(ctx
);
616 static inline void __io_cq_lock(struct io_ring_ctx
*ctx
)
618 if (!ctx
->lockless_cq
)
619 spin_lock(&ctx
->completion_lock
);
622 static inline void io_cq_lock(struct io_ring_ctx
*ctx
)
623 __acquires(ctx
->completion_lock
)
625 spin_lock(&ctx
->completion_lock
);
628 static inline void __io_cq_unlock_post(struct io_ring_ctx
*ctx
)
630 io_commit_cqring(ctx
);
631 if (!ctx
->task_complete
) {
632 if (!ctx
->lockless_cq
)
633 spin_unlock(&ctx
->completion_lock
);
634 /* IOPOLL rings only need to wake up if it's also SQPOLL */
635 if (!ctx
->syscall_iopoll
)
638 io_commit_cqring_flush(ctx
);
641 static void io_cq_unlock_post(struct io_ring_ctx
*ctx
)
642 __releases(ctx
->completion_lock
)
644 io_commit_cqring(ctx
);
645 spin_unlock(&ctx
->completion_lock
);
647 io_commit_cqring_flush(ctx
);
650 /* Returns true if there are no backlogged entries after the flush */
651 static void io_cqring_overflow_kill(struct io_ring_ctx
*ctx
)
653 struct io_overflow_cqe
*ocqe
;
656 spin_lock(&ctx
->completion_lock
);
657 list_splice_init(&ctx
->cq_overflow_list
, &list
);
658 clear_bit(IO_CHECK_CQ_OVERFLOW_BIT
, &ctx
->check_cq
);
659 spin_unlock(&ctx
->completion_lock
);
661 while (!list_empty(&list
)) {
662 ocqe
= list_first_entry(&list
, struct io_overflow_cqe
, list
);
663 list_del(&ocqe
->list
);
668 static void __io_cqring_overflow_flush(struct io_ring_ctx
*ctx
)
670 size_t cqe_size
= sizeof(struct io_uring_cqe
);
672 if (__io_cqring_events(ctx
) == ctx
->cq_entries
)
675 if (ctx
->flags
& IORING_SETUP_CQE32
)
679 while (!list_empty(&ctx
->cq_overflow_list
)) {
680 struct io_uring_cqe
*cqe
;
681 struct io_overflow_cqe
*ocqe
;
683 if (!io_get_cqe_overflow(ctx
, &cqe
, true))
685 ocqe
= list_first_entry(&ctx
->cq_overflow_list
,
686 struct io_overflow_cqe
, list
);
687 memcpy(cqe
, &ocqe
->cqe
, cqe_size
);
688 list_del(&ocqe
->list
);
692 if (list_empty(&ctx
->cq_overflow_list
)) {
693 clear_bit(IO_CHECK_CQ_OVERFLOW_BIT
, &ctx
->check_cq
);
694 atomic_andnot(IORING_SQ_CQ_OVERFLOW
, &ctx
->rings
->sq_flags
);
696 io_cq_unlock_post(ctx
);
699 static void io_cqring_do_overflow_flush(struct io_ring_ctx
*ctx
)
701 /* iopoll syncs against uring_lock, not completion_lock */
702 if (ctx
->flags
& IORING_SETUP_IOPOLL
)
703 mutex_lock(&ctx
->uring_lock
);
704 __io_cqring_overflow_flush(ctx
);
705 if (ctx
->flags
& IORING_SETUP_IOPOLL
)
706 mutex_unlock(&ctx
->uring_lock
);
709 static void io_cqring_overflow_flush(struct io_ring_ctx
*ctx
)
711 if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT
, &ctx
->check_cq
))
712 io_cqring_do_overflow_flush(ctx
);
715 /* can be called by any task */
716 static void io_put_task_remote(struct task_struct
*task
)
718 struct io_uring_task
*tctx
= task
->io_uring
;
720 percpu_counter_sub(&tctx
->inflight
, 1);
721 if (unlikely(atomic_read(&tctx
->in_cancel
)))
722 wake_up(&tctx
->wait
);
723 put_task_struct(task
);
726 /* used by a task to put its own references */
727 static void io_put_task_local(struct task_struct
*task
)
729 task
->io_uring
->cached_refs
++;
732 /* must to be called somewhat shortly after putting a request */
733 static inline void io_put_task(struct task_struct
*task
)
735 if (likely(task
== current
))
736 io_put_task_local(task
);
738 io_put_task_remote(task
);
741 void io_task_refs_refill(struct io_uring_task
*tctx
)
743 unsigned int refill
= -tctx
->cached_refs
+ IO_TCTX_REFS_CACHE_NR
;
745 percpu_counter_add(&tctx
->inflight
, refill
);
746 refcount_add(refill
, ¤t
->usage
);
747 tctx
->cached_refs
+= refill
;
750 static __cold
void io_uring_drop_tctx_refs(struct task_struct
*task
)
752 struct io_uring_task
*tctx
= task
->io_uring
;
753 unsigned int refs
= tctx
->cached_refs
;
756 tctx
->cached_refs
= 0;
757 percpu_counter_sub(&tctx
->inflight
, refs
);
758 put_task_struct_many(task
, refs
);
762 static bool io_cqring_event_overflow(struct io_ring_ctx
*ctx
, u64 user_data
,
763 s32 res
, u32 cflags
, u64 extra1
, u64 extra2
)
765 struct io_overflow_cqe
*ocqe
;
766 size_t ocq_size
= sizeof(struct io_overflow_cqe
);
767 bool is_cqe32
= (ctx
->flags
& IORING_SETUP_CQE32
);
769 lockdep_assert_held(&ctx
->completion_lock
);
772 ocq_size
+= sizeof(struct io_uring_cqe
);
774 ocqe
= kmalloc(ocq_size
, GFP_ATOMIC
| __GFP_ACCOUNT
);
775 trace_io_uring_cqe_overflow(ctx
, user_data
, res
, cflags
, ocqe
);
778 * If we're in ring overflow flush mode, or in task cancel mode,
779 * or cannot allocate an overflow entry, then we need to drop it
782 io_account_cq_overflow(ctx
);
783 set_bit(IO_CHECK_CQ_DROPPED_BIT
, &ctx
->check_cq
);
786 if (list_empty(&ctx
->cq_overflow_list
)) {
787 set_bit(IO_CHECK_CQ_OVERFLOW_BIT
, &ctx
->check_cq
);
788 atomic_or(IORING_SQ_CQ_OVERFLOW
, &ctx
->rings
->sq_flags
);
791 ocqe
->cqe
.user_data
= user_data
;
793 ocqe
->cqe
.flags
= cflags
;
795 ocqe
->cqe
.big_cqe
[0] = extra1
;
796 ocqe
->cqe
.big_cqe
[1] = extra2
;
798 list_add_tail(&ocqe
->list
, &ctx
->cq_overflow_list
);
802 void io_req_cqe_overflow(struct io_kiocb
*req
)
804 io_cqring_event_overflow(req
->ctx
, req
->cqe
.user_data
,
805 req
->cqe
.res
, req
->cqe
.flags
,
806 req
->big_cqe
.extra1
, req
->big_cqe
.extra2
);
807 memset(&req
->big_cqe
, 0, sizeof(req
->big_cqe
));
811 * writes to the cq entry need to come after reading head; the
812 * control dependency is enough as we're using WRITE_ONCE to
815 bool io_cqe_cache_refill(struct io_ring_ctx
*ctx
, bool overflow
)
817 struct io_rings
*rings
= ctx
->rings
;
818 unsigned int off
= ctx
->cached_cq_tail
& (ctx
->cq_entries
- 1);
819 unsigned int free
, queued
, len
;
822 * Posting into the CQ when there are pending overflowed CQEs may break
823 * ordering guarantees, which will affect links, F_MORE users and more.
824 * Force overflow the completion.
826 if (!overflow
&& (ctx
->check_cq
& BIT(IO_CHECK_CQ_OVERFLOW_BIT
)))
829 /* userspace may cheat modifying the tail, be safe and do min */
830 queued
= min(__io_cqring_events(ctx
), ctx
->cq_entries
);
831 free
= ctx
->cq_entries
- queued
;
832 /* we need a contiguous range, limit based on the current array offset */
833 len
= min(free
, ctx
->cq_entries
- off
);
837 if (ctx
->flags
& IORING_SETUP_CQE32
) {
842 ctx
->cqe_cached
= &rings
->cqes
[off
];
843 ctx
->cqe_sentinel
= ctx
->cqe_cached
+ len
;
847 static bool io_fill_cqe_aux(struct io_ring_ctx
*ctx
, u64 user_data
, s32 res
,
850 struct io_uring_cqe
*cqe
;
855 * If we can't get a cq entry, userspace overflowed the
856 * submission (by quite a lot). Increment the overflow count in
859 if (likely(io_get_cqe(ctx
, &cqe
))) {
860 trace_io_uring_complete(ctx
, NULL
, user_data
, res
, cflags
, 0, 0);
862 WRITE_ONCE(cqe
->user_data
, user_data
);
863 WRITE_ONCE(cqe
->res
, res
);
864 WRITE_ONCE(cqe
->flags
, cflags
);
866 if (ctx
->flags
& IORING_SETUP_CQE32
) {
867 WRITE_ONCE(cqe
->big_cqe
[0], 0);
868 WRITE_ONCE(cqe
->big_cqe
[1], 0);
875 static void __io_flush_post_cqes(struct io_ring_ctx
*ctx
)
876 __must_hold(&ctx
->uring_lock
)
878 struct io_submit_state
*state
= &ctx
->submit_state
;
881 lockdep_assert_held(&ctx
->uring_lock
);
882 for (i
= 0; i
< state
->cqes_count
; i
++) {
883 struct io_uring_cqe
*cqe
= &ctx
->completion_cqes
[i
];
885 if (!io_fill_cqe_aux(ctx
, cqe
->user_data
, cqe
->res
, cqe
->flags
)) {
886 if (ctx
->task_complete
) {
887 spin_lock(&ctx
->completion_lock
);
888 io_cqring_event_overflow(ctx
, cqe
->user_data
,
889 cqe
->res
, cqe
->flags
, 0, 0);
890 spin_unlock(&ctx
->completion_lock
);
892 io_cqring_event_overflow(ctx
, cqe
->user_data
,
893 cqe
->res
, cqe
->flags
, 0, 0);
897 state
->cqes_count
= 0;
900 static bool __io_post_aux_cqe(struct io_ring_ctx
*ctx
, u64 user_data
, s32 res
, u32 cflags
,
906 filled
= io_fill_cqe_aux(ctx
, user_data
, res
, cflags
);
907 if (!filled
&& allow_overflow
)
908 filled
= io_cqring_event_overflow(ctx
, user_data
, res
, cflags
, 0, 0);
910 io_cq_unlock_post(ctx
);
914 bool io_post_aux_cqe(struct io_ring_ctx
*ctx
, u64 user_data
, s32 res
, u32 cflags
)
916 return __io_post_aux_cqe(ctx
, user_data
, res
, cflags
, true);
920 * A helper for multishot requests posting additional CQEs.
921 * Should only be used from a task_work including IO_URING_F_MULTISHOT.
923 bool io_fill_cqe_req_aux(struct io_kiocb
*req
, bool defer
, s32 res
, u32 cflags
)
925 struct io_ring_ctx
*ctx
= req
->ctx
;
926 u64 user_data
= req
->cqe
.user_data
;
927 struct io_uring_cqe
*cqe
;
930 return __io_post_aux_cqe(ctx
, user_data
, res
, cflags
, false);
932 lockdep_assert_held(&ctx
->uring_lock
);
934 if (ctx
->submit_state
.cqes_count
== ARRAY_SIZE(ctx
->completion_cqes
)) {
936 __io_flush_post_cqes(ctx
);
937 /* no need to flush - flush is deferred */
938 __io_cq_unlock_post(ctx
);
941 /* For defered completions this is not as strict as it is otherwise,
942 * however it's main job is to prevent unbounded posted completions,
943 * and in that it works just as well.
945 if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT
, &ctx
->check_cq
))
948 cqe
= &ctx
->completion_cqes
[ctx
->submit_state
.cqes_count
++];
949 cqe
->user_data
= user_data
;
955 static void __io_req_complete_post(struct io_kiocb
*req
, unsigned issue_flags
)
957 struct io_ring_ctx
*ctx
= req
->ctx
;
958 struct io_rsrc_node
*rsrc_node
= NULL
;
961 if (!(req
->flags
& REQ_F_CQE_SKIP
)) {
962 if (!io_fill_cqe_req(ctx
, req
))
963 io_req_cqe_overflow(req
);
967 * If we're the last reference to this request, add to our locked
970 if (req_ref_put_and_test(req
)) {
971 if (req
->flags
& IO_REQ_LINK_FLAGS
) {
972 if (req
->flags
& IO_DISARM_MASK
)
975 io_req_task_queue(req
->link
);
979 io_put_kbuf_comp(req
);
980 if (unlikely(req
->flags
& IO_REQ_CLEAN_FLAGS
))
984 rsrc_node
= req
->rsrc_node
;
986 * Selected buffer deallocation in io_clean_op() assumes that
987 * we don't hold ->completion_lock. Clean them here to avoid
990 io_put_task_remote(req
->task
);
991 wq_list_add_head(&req
->comp_list
, &ctx
->locked_free_list
);
992 ctx
->locked_free_nr
++;
994 io_cq_unlock_post(ctx
);
997 io_ring_submit_lock(ctx
, issue_flags
);
998 io_put_rsrc_node(ctx
, rsrc_node
);
999 io_ring_submit_unlock(ctx
, issue_flags
);
1003 void io_req_complete_post(struct io_kiocb
*req
, unsigned issue_flags
)
1005 if (req
->ctx
->task_complete
&& req
->ctx
->submitter_task
!= current
) {
1006 req
->io_task_work
.func
= io_req_task_complete
;
1007 io_req_task_work_add(req
);
1008 } else if (!(issue_flags
& IO_URING_F_UNLOCKED
) ||
1009 !(req
->ctx
->flags
& IORING_SETUP_IOPOLL
)) {
1010 __io_req_complete_post(req
, issue_flags
);
1012 struct io_ring_ctx
*ctx
= req
->ctx
;
1014 mutex_lock(&ctx
->uring_lock
);
1015 __io_req_complete_post(req
, issue_flags
& ~IO_URING_F_UNLOCKED
);
1016 mutex_unlock(&ctx
->uring_lock
);
1020 void io_req_defer_failed(struct io_kiocb
*req
, s32 res
)
1021 __must_hold(&ctx
->uring_lock
)
1023 const struct io_cold_def
*def
= &io_cold_defs
[req
->opcode
];
1025 lockdep_assert_held(&req
->ctx
->uring_lock
);
1028 io_req_set_res(req
, res
, io_put_kbuf(req
, IO_URING_F_UNLOCKED
));
1031 io_req_complete_defer(req
);
1035 * Don't initialise the fields below on every allocation, but do that in
1036 * advance and keep them valid across allocations.
1038 static void io_preinit_req(struct io_kiocb
*req
, struct io_ring_ctx
*ctx
)
1042 req
->async_data
= NULL
;
1043 /* not necessary, but safer to zero */
1044 memset(&req
->cqe
, 0, sizeof(req
->cqe
));
1045 memset(&req
->big_cqe
, 0, sizeof(req
->big_cqe
));
1048 static void io_flush_cached_locked_reqs(struct io_ring_ctx
*ctx
,
1049 struct io_submit_state
*state
)
1051 spin_lock(&ctx
->completion_lock
);
1052 wq_list_splice(&ctx
->locked_free_list
, &state
->free_list
);
1053 ctx
->locked_free_nr
= 0;
1054 spin_unlock(&ctx
->completion_lock
);
1058 * A request might get retired back into the request caches even before opcode
1059 * handlers and io_issue_sqe() are done with it, e.g. inline completion path.
1060 * Because of that, io_alloc_req() should be called only under ->uring_lock
1061 * and with extra caution to not get a request that is still worked on.
1063 __cold
bool __io_alloc_req_refill(struct io_ring_ctx
*ctx
)
1064 __must_hold(&ctx
->uring_lock
)
1066 gfp_t gfp
= GFP_KERNEL
| __GFP_NOWARN
;
1067 void *reqs
[IO_REQ_ALLOC_BATCH
];
1071 * If we have more than a batch's worth of requests in our IRQ side
1072 * locked cache, grab the lock and move them over to our submission
1075 if (data_race(ctx
->locked_free_nr
) > IO_COMPL_BATCH
) {
1076 io_flush_cached_locked_reqs(ctx
, &ctx
->submit_state
);
1077 if (!io_req_cache_empty(ctx
))
1081 ret
= kmem_cache_alloc_bulk(req_cachep
, gfp
, ARRAY_SIZE(reqs
), reqs
);
1084 * Bulk alloc is all-or-nothing. If we fail to get a batch,
1085 * retry single alloc to be on the safe side.
1087 if (unlikely(ret
<= 0)) {
1088 reqs
[0] = kmem_cache_alloc(req_cachep
, gfp
);
1094 percpu_ref_get_many(&ctx
->refs
, ret
);
1095 for (i
= 0; i
< ret
; i
++) {
1096 struct io_kiocb
*req
= reqs
[i
];
1098 io_preinit_req(req
, ctx
);
1099 io_req_add_to_cache(req
, ctx
);
1104 __cold
void io_free_req(struct io_kiocb
*req
)
1106 /* refs were already put, restore them for io_req_task_complete() */
1107 req
->flags
&= ~REQ_F_REFCOUNT
;
1108 /* we only want to free it, don't post CQEs */
1109 req
->flags
|= REQ_F_CQE_SKIP
;
1110 req
->io_task_work
.func
= io_req_task_complete
;
1111 io_req_task_work_add(req
);
1114 static void __io_req_find_next_prep(struct io_kiocb
*req
)
1116 struct io_ring_ctx
*ctx
= req
->ctx
;
1118 spin_lock(&ctx
->completion_lock
);
1119 io_disarm_next(req
);
1120 spin_unlock(&ctx
->completion_lock
);
1123 static inline struct io_kiocb
*io_req_find_next(struct io_kiocb
*req
)
1125 struct io_kiocb
*nxt
;
1128 * If LINK is set, we have dependent requests in this chain. If we
1129 * didn't fail this request, queue the first one up, moving any other
1130 * dependencies to the next request. In case of failure, fail the rest
1133 if (unlikely(req
->flags
& IO_DISARM_MASK
))
1134 __io_req_find_next_prep(req
);
1140 static void ctx_flush_and_put(struct io_ring_ctx
*ctx
, struct io_tw_state
*ts
)
1144 if (ctx
->flags
& IORING_SETUP_TASKRUN_FLAG
)
1145 atomic_andnot(IORING_SQ_TASKRUN
, &ctx
->rings
->sq_flags
);
1147 io_submit_flush_completions(ctx
);
1148 mutex_unlock(&ctx
->uring_lock
);
1151 percpu_ref_put(&ctx
->refs
);
1154 static unsigned int handle_tw_list(struct llist_node
*node
,
1155 struct io_ring_ctx
**ctx
,
1156 struct io_tw_state
*ts
,
1157 struct llist_node
*last
)
1159 unsigned int count
= 0;
1161 while (node
&& node
!= last
) {
1162 struct llist_node
*next
= node
->next
;
1163 struct io_kiocb
*req
= container_of(node
, struct io_kiocb
,
1166 prefetch(container_of(next
, struct io_kiocb
, io_task_work
.node
));
1168 if (req
->ctx
!= *ctx
) {
1169 ctx_flush_and_put(*ctx
, ts
);
1171 /* if not contended, grab and improve batching */
1172 ts
->locked
= mutex_trylock(&(*ctx
)->uring_lock
);
1173 percpu_ref_get(&(*ctx
)->refs
);
1175 INDIRECT_CALL_2(req
->io_task_work
.func
,
1176 io_poll_task_func
, io_req_rw_complete
,
1180 if (unlikely(need_resched())) {
1181 ctx_flush_and_put(*ctx
, ts
);
1191 * io_llist_xchg - swap all entries in a lock-less list
1192 * @head: the head of lock-less list to delete all entries
1193 * @new: new entry as the head of the list
1195 * If list is empty, return NULL, otherwise, return the pointer to the first entry.
1196 * The order of entries returned is from the newest to the oldest added one.
1198 static inline struct llist_node
*io_llist_xchg(struct llist_head
*head
,
1199 struct llist_node
*new)
1201 return xchg(&head
->first
, new);
1205 * io_llist_cmpxchg - possibly swap all entries in a lock-less list
1206 * @head: the head of lock-less list to delete all entries
1207 * @old: expected old value of the first entry of the list
1208 * @new: new entry as the head of the list
1210 * perform a cmpxchg on the first entry of the list.
1213 static inline struct llist_node
*io_llist_cmpxchg(struct llist_head
*head
,
1214 struct llist_node
*old
,
1215 struct llist_node
*new)
1217 return cmpxchg(&head
->first
, old
, new);
1220 static __cold
void io_fallback_tw(struct io_uring_task
*tctx
, bool sync
)
1222 struct llist_node
*node
= llist_del_all(&tctx
->task_list
);
1223 struct io_ring_ctx
*last_ctx
= NULL
;
1224 struct io_kiocb
*req
;
1227 req
= container_of(node
, struct io_kiocb
, io_task_work
.node
);
1229 if (sync
&& last_ctx
!= req
->ctx
) {
1231 flush_delayed_work(&last_ctx
->fallback_work
);
1232 percpu_ref_put(&last_ctx
->refs
);
1234 last_ctx
= req
->ctx
;
1235 percpu_ref_get(&last_ctx
->refs
);
1237 if (llist_add(&req
->io_task_work
.node
,
1238 &req
->ctx
->fallback_llist
))
1239 schedule_delayed_work(&req
->ctx
->fallback_work
, 1);
1243 flush_delayed_work(&last_ctx
->fallback_work
);
1244 percpu_ref_put(&last_ctx
->refs
);
1248 void tctx_task_work(struct callback_head
*cb
)
1250 struct io_tw_state ts
= {};
1251 struct io_ring_ctx
*ctx
= NULL
;
1252 struct io_uring_task
*tctx
= container_of(cb
, struct io_uring_task
,
1254 struct llist_node fake
= {};
1255 struct llist_node
*node
;
1256 unsigned int loops
= 0;
1257 unsigned int count
= 0;
1259 if (unlikely(current
->flags
& PF_EXITING
)) {
1260 io_fallback_tw(tctx
, true);
1266 node
= io_llist_xchg(&tctx
->task_list
, &fake
);
1267 count
+= handle_tw_list(node
, &ctx
, &ts
, &fake
);
1269 /* skip expensive cmpxchg if there are items in the list */
1270 if (READ_ONCE(tctx
->task_list
.first
) != &fake
)
1272 if (ts
.locked
&& !wq_list_empty(&ctx
->submit_state
.compl_reqs
)) {
1273 io_submit_flush_completions(ctx
);
1274 if (READ_ONCE(tctx
->task_list
.first
) != &fake
)
1277 node
= io_llist_cmpxchg(&tctx
->task_list
, &fake
, NULL
);
1278 } while (node
!= &fake
);
1280 ctx_flush_and_put(ctx
, &ts
);
1282 /* relaxed read is enough as only the task itself sets ->in_cancel */
1283 if (unlikely(atomic_read(&tctx
->in_cancel
)))
1284 io_uring_drop_tctx_refs(current
);
1286 trace_io_uring_task_work_run(tctx
, count
, loops
);
1289 static inline void io_req_local_work_add(struct io_kiocb
*req
, unsigned flags
)
1291 struct io_ring_ctx
*ctx
= req
->ctx
;
1292 unsigned nr_wait
, nr_tw
, nr_tw_prev
;
1293 struct llist_node
*first
;
1295 if (req
->flags
& (REQ_F_LINK
| REQ_F_HARDLINK
))
1296 flags
&= ~IOU_F_TWQ_LAZY_WAKE
;
1298 first
= READ_ONCE(ctx
->work_llist
.first
);
1302 struct io_kiocb
*first_req
= container_of(first
,
1306 * Might be executed at any moment, rely on
1307 * SLAB_TYPESAFE_BY_RCU to keep it alive.
1309 nr_tw_prev
= READ_ONCE(first_req
->nr_tw
);
1311 nr_tw
= nr_tw_prev
+ 1;
1312 /* Large enough to fail the nr_wait comparison below */
1313 if (!(flags
& IOU_F_TWQ_LAZY_WAKE
))
1317 req
->io_task_work
.node
.next
= first
;
1318 } while (!try_cmpxchg(&ctx
->work_llist
.first
, &first
,
1319 &req
->io_task_work
.node
));
1322 if (ctx
->flags
& IORING_SETUP_TASKRUN_FLAG
)
1323 atomic_or(IORING_SQ_TASKRUN
, &ctx
->rings
->sq_flags
);
1325 io_eventfd_signal(ctx
);
1328 nr_wait
= atomic_read(&ctx
->cq_wait_nr
);
1329 /* no one is waiting */
1332 /* either not enough or the previous add has already woken it up */
1333 if (nr_wait
> nr_tw
|| nr_tw_prev
>= nr_wait
)
1335 /* pairs with set_current_state() in io_cqring_wait() */
1336 smp_mb__after_atomic();
1337 wake_up_state(ctx
->submitter_task
, TASK_INTERRUPTIBLE
);
1340 static void io_req_normal_work_add(struct io_kiocb
*req
)
1342 struct io_uring_task
*tctx
= req
->task
->io_uring
;
1343 struct io_ring_ctx
*ctx
= req
->ctx
;
1345 /* task_work already pending, we're done */
1346 if (!llist_add(&req
->io_task_work
.node
, &tctx
->task_list
))
1349 if (ctx
->flags
& IORING_SETUP_TASKRUN_FLAG
)
1350 atomic_or(IORING_SQ_TASKRUN
, &ctx
->rings
->sq_flags
);
1352 if (likely(!task_work_add(req
->task
, &tctx
->task_work
, ctx
->notify_method
)))
1355 io_fallback_tw(tctx
, false);
1358 void __io_req_task_work_add(struct io_kiocb
*req
, unsigned flags
)
1360 if (req
->ctx
->flags
& IORING_SETUP_DEFER_TASKRUN
) {
1362 io_req_local_work_add(req
, flags
);
1365 io_req_normal_work_add(req
);
1369 static void __cold
io_move_task_work_from_local(struct io_ring_ctx
*ctx
)
1371 struct llist_node
*node
;
1373 node
= llist_del_all(&ctx
->work_llist
);
1375 struct io_kiocb
*req
= container_of(node
, struct io_kiocb
,
1379 io_req_normal_work_add(req
);
1383 static int __io_run_local_work(struct io_ring_ctx
*ctx
, struct io_tw_state
*ts
)
1385 struct llist_node
*node
;
1386 unsigned int loops
= 0;
1389 if (WARN_ON_ONCE(ctx
->submitter_task
!= current
))
1391 if (ctx
->flags
& IORING_SETUP_TASKRUN_FLAG
)
1392 atomic_andnot(IORING_SQ_TASKRUN
, &ctx
->rings
->sq_flags
);
1395 * llists are in reverse order, flip it back the right way before
1396 * running the pending items.
1398 node
= llist_reverse_order(io_llist_xchg(&ctx
->work_llist
, NULL
));
1400 struct llist_node
*next
= node
->next
;
1401 struct io_kiocb
*req
= container_of(node
, struct io_kiocb
,
1403 prefetch(container_of(next
, struct io_kiocb
, io_task_work
.node
));
1404 INDIRECT_CALL_2(req
->io_task_work
.func
,
1405 io_poll_task_func
, io_req_rw_complete
,
1412 if (!llist_empty(&ctx
->work_llist
))
1415 io_submit_flush_completions(ctx
);
1416 if (!llist_empty(&ctx
->work_llist
))
1419 trace_io_uring_local_work_run(ctx
, ret
, loops
);
1423 static inline int io_run_local_work_locked(struct io_ring_ctx
*ctx
)
1425 struct io_tw_state ts
= { .locked
= true, };
1428 if (llist_empty(&ctx
->work_llist
))
1431 ret
= __io_run_local_work(ctx
, &ts
);
1432 /* shouldn't happen! */
1433 if (WARN_ON_ONCE(!ts
.locked
))
1434 mutex_lock(&ctx
->uring_lock
);
1438 static int io_run_local_work(struct io_ring_ctx
*ctx
)
1440 struct io_tw_state ts
= {};
1443 ts
.locked
= mutex_trylock(&ctx
->uring_lock
);
1444 ret
= __io_run_local_work(ctx
, &ts
);
1446 mutex_unlock(&ctx
->uring_lock
);
1451 static void io_req_task_cancel(struct io_kiocb
*req
, struct io_tw_state
*ts
)
1453 io_tw_lock(req
->ctx
, ts
);
1454 io_req_defer_failed(req
, req
->cqe
.res
);
1457 void io_req_task_submit(struct io_kiocb
*req
, struct io_tw_state
*ts
)
1459 io_tw_lock(req
->ctx
, ts
);
1460 /* req->task == current here, checking PF_EXITING is safe */
1461 if (unlikely(req
->task
->flags
& PF_EXITING
))
1462 io_req_defer_failed(req
, -EFAULT
);
1463 else if (req
->flags
& REQ_F_FORCE_ASYNC
)
1464 io_queue_iowq(req
, ts
);
1469 void io_req_task_queue_fail(struct io_kiocb
*req
, int ret
)
1471 io_req_set_res(req
, ret
, 0);
1472 req
->io_task_work
.func
= io_req_task_cancel
;
1473 io_req_task_work_add(req
);
1476 void io_req_task_queue(struct io_kiocb
*req
)
1478 req
->io_task_work
.func
= io_req_task_submit
;
1479 io_req_task_work_add(req
);
1482 void io_queue_next(struct io_kiocb
*req
)
1484 struct io_kiocb
*nxt
= io_req_find_next(req
);
1487 io_req_task_queue(nxt
);
1490 static void io_free_batch_list(struct io_ring_ctx
*ctx
,
1491 struct io_wq_work_node
*node
)
1492 __must_hold(&ctx
->uring_lock
)
1495 struct io_kiocb
*req
= container_of(node
, struct io_kiocb
,
1498 if (unlikely(req
->flags
& IO_REQ_CLEAN_SLOW_FLAGS
)) {
1499 if (req
->flags
& REQ_F_REFCOUNT
) {
1500 node
= req
->comp_list
.next
;
1501 if (!req_ref_put_and_test(req
))
1504 if ((req
->flags
& REQ_F_POLLED
) && req
->apoll
) {
1505 struct async_poll
*apoll
= req
->apoll
;
1507 if (apoll
->double_poll
)
1508 kfree(apoll
->double_poll
);
1509 if (!io_alloc_cache_put(&ctx
->apoll_cache
, &apoll
->cache
))
1511 req
->flags
&= ~REQ_F_POLLED
;
1513 if (req
->flags
& IO_REQ_LINK_FLAGS
)
1515 if (unlikely(req
->flags
& IO_REQ_CLEAN_FLAGS
))
1520 io_req_put_rsrc_locked(req
, ctx
);
1522 io_put_task(req
->task
);
1523 node
= req
->comp_list
.next
;
1524 io_req_add_to_cache(req
, ctx
);
1528 void __io_submit_flush_completions(struct io_ring_ctx
*ctx
)
1529 __must_hold(&ctx
->uring_lock
)
1531 struct io_submit_state
*state
= &ctx
->submit_state
;
1532 struct io_wq_work_node
*node
;
1535 /* must come first to preserve CQE ordering in failure cases */
1536 if (state
->cqes_count
)
1537 __io_flush_post_cqes(ctx
);
1538 __wq_list_for_each(node
, &state
->compl_reqs
) {
1539 struct io_kiocb
*req
= container_of(node
, struct io_kiocb
,
1542 if (!(req
->flags
& REQ_F_CQE_SKIP
) &&
1543 unlikely(!io_fill_cqe_req(ctx
, req
))) {
1544 if (ctx
->task_complete
) {
1545 spin_lock(&ctx
->completion_lock
);
1546 io_req_cqe_overflow(req
);
1547 spin_unlock(&ctx
->completion_lock
);
1549 io_req_cqe_overflow(req
);
1553 __io_cq_unlock_post(ctx
);
1555 if (!wq_list_empty(&ctx
->submit_state
.compl_reqs
)) {
1556 io_free_batch_list(ctx
, state
->compl_reqs
.first
);
1557 INIT_WQ_LIST(&state
->compl_reqs
);
1561 static unsigned io_cqring_events(struct io_ring_ctx
*ctx
)
1563 /* See comment at the top of this file */
1565 return __io_cqring_events(ctx
);
1569 * We can't just wait for polled events to come to us, we have to actively
1570 * find and complete them.
1572 static __cold
void io_iopoll_try_reap_events(struct io_ring_ctx
*ctx
)
1574 if (!(ctx
->flags
& IORING_SETUP_IOPOLL
))
1577 mutex_lock(&ctx
->uring_lock
);
1578 while (!wq_list_empty(&ctx
->iopoll_list
)) {
1579 /* let it sleep and repeat later if can't complete a request */
1580 if (io_do_iopoll(ctx
, true) == 0)
1583 * Ensure we allow local-to-the-cpu processing to take place,
1584 * in this case we need to ensure that we reap all events.
1585 * Also let task_work, etc. to progress by releasing the mutex
1587 if (need_resched()) {
1588 mutex_unlock(&ctx
->uring_lock
);
1590 mutex_lock(&ctx
->uring_lock
);
1593 mutex_unlock(&ctx
->uring_lock
);
1596 static int io_iopoll_check(struct io_ring_ctx
*ctx
, long min
)
1598 unsigned int nr_events
= 0;
1599 unsigned long check_cq
;
1601 if (!io_allowed_run_tw(ctx
))
1604 check_cq
= READ_ONCE(ctx
->check_cq
);
1605 if (unlikely(check_cq
)) {
1606 if (check_cq
& BIT(IO_CHECK_CQ_OVERFLOW_BIT
))
1607 __io_cqring_overflow_flush(ctx
);
1609 * Similarly do not spin if we have not informed the user of any
1612 if (check_cq
& BIT(IO_CHECK_CQ_DROPPED_BIT
))
1616 * Don't enter poll loop if we already have events pending.
1617 * If we do, we can potentially be spinning for commands that
1618 * already triggered a CQE (eg in error).
1620 if (io_cqring_events(ctx
))
1627 * If a submit got punted to a workqueue, we can have the
1628 * application entering polling for a command before it gets
1629 * issued. That app will hold the uring_lock for the duration
1630 * of the poll right here, so we need to take a breather every
1631 * now and then to ensure that the issue has a chance to add
1632 * the poll to the issued list. Otherwise we can spin here
1633 * forever, while the workqueue is stuck trying to acquire the
1636 if (wq_list_empty(&ctx
->iopoll_list
) ||
1637 io_task_work_pending(ctx
)) {
1638 u32 tail
= ctx
->cached_cq_tail
;
1640 (void) io_run_local_work_locked(ctx
);
1642 if (task_work_pending(current
) ||
1643 wq_list_empty(&ctx
->iopoll_list
)) {
1644 mutex_unlock(&ctx
->uring_lock
);
1646 mutex_lock(&ctx
->uring_lock
);
1648 /* some requests don't go through iopoll_list */
1649 if (tail
!= ctx
->cached_cq_tail
||
1650 wq_list_empty(&ctx
->iopoll_list
))
1653 ret
= io_do_iopoll(ctx
, !min
);
1654 if (unlikely(ret
< 0))
1657 if (task_sigpending(current
))
1663 } while (nr_events
< min
);
1668 void io_req_task_complete(struct io_kiocb
*req
, struct io_tw_state
*ts
)
1671 io_req_complete_defer(req
);
1673 io_req_complete_post(req
, IO_URING_F_UNLOCKED
);
1677 * After the iocb has been issued, it's safe to be found on the poll list.
1678 * Adding the kiocb to the list AFTER submission ensures that we don't
1679 * find it from a io_do_iopoll() thread before the issuer is done
1680 * accessing the kiocb cookie.
1682 static void io_iopoll_req_issued(struct io_kiocb
*req
, unsigned int issue_flags
)
1684 struct io_ring_ctx
*ctx
= req
->ctx
;
1685 const bool needs_lock
= issue_flags
& IO_URING_F_UNLOCKED
;
1687 /* workqueue context doesn't hold uring_lock, grab it now */
1688 if (unlikely(needs_lock
))
1689 mutex_lock(&ctx
->uring_lock
);
1692 * Track whether we have multiple files in our lists. This will impact
1693 * how we do polling eventually, not spinning if we're on potentially
1694 * different devices.
1696 if (wq_list_empty(&ctx
->iopoll_list
)) {
1697 ctx
->poll_multi_queue
= false;
1698 } else if (!ctx
->poll_multi_queue
) {
1699 struct io_kiocb
*list_req
;
1701 list_req
= container_of(ctx
->iopoll_list
.first
, struct io_kiocb
,
1703 if (list_req
->file
!= req
->file
)
1704 ctx
->poll_multi_queue
= true;
1708 * For fast devices, IO may have already completed. If it has, add
1709 * it to the front so we find it first.
1711 if (READ_ONCE(req
->iopoll_completed
))
1712 wq_list_add_head(&req
->comp_list
, &ctx
->iopoll_list
);
1714 wq_list_add_tail(&req
->comp_list
, &ctx
->iopoll_list
);
1716 if (unlikely(needs_lock
)) {
1718 * If IORING_SETUP_SQPOLL is enabled, sqes are either handle
1719 * in sq thread task context or in io worker task context. If
1720 * current task context is sq thread, we don't need to check
1721 * whether should wake up sq thread.
1723 if ((ctx
->flags
& IORING_SETUP_SQPOLL
) &&
1724 wq_has_sleeper(&ctx
->sq_data
->wait
))
1725 wake_up(&ctx
->sq_data
->wait
);
1727 mutex_unlock(&ctx
->uring_lock
);
1731 unsigned int io_file_get_flags(struct file
*file
)
1733 unsigned int res
= 0;
1735 if (S_ISREG(file_inode(file
)->i_mode
))
1737 if ((file
->f_flags
& O_NONBLOCK
) || (file
->f_mode
& FMODE_NOWAIT
))
1738 res
|= REQ_F_SUPPORT_NOWAIT
;
1742 bool io_alloc_async_data(struct io_kiocb
*req
)
1744 WARN_ON_ONCE(!io_cold_defs
[req
->opcode
].async_size
);
1745 req
->async_data
= kmalloc(io_cold_defs
[req
->opcode
].async_size
, GFP_KERNEL
);
1746 if (req
->async_data
) {
1747 req
->flags
|= REQ_F_ASYNC_DATA
;
1753 int io_req_prep_async(struct io_kiocb
*req
)
1755 const struct io_cold_def
*cdef
= &io_cold_defs
[req
->opcode
];
1756 const struct io_issue_def
*def
= &io_issue_defs
[req
->opcode
];
1758 /* assign early for deferred execution for non-fixed file */
1759 if (def
->needs_file
&& !(req
->flags
& REQ_F_FIXED_FILE
) && !req
->file
)
1760 req
->file
= io_file_get_normal(req
, req
->cqe
.fd
);
1761 if (!cdef
->prep_async
)
1763 if (WARN_ON_ONCE(req_has_async_data(req
)))
1765 if (!def
->manual_alloc
) {
1766 if (io_alloc_async_data(req
))
1769 return cdef
->prep_async(req
);
1772 static u32
io_get_sequence(struct io_kiocb
*req
)
1774 u32 seq
= req
->ctx
->cached_sq_head
;
1775 struct io_kiocb
*cur
;
1777 /* need original cached_sq_head, but it was increased for each req */
1778 io_for_each_link(cur
, req
)
1783 static __cold
void io_drain_req(struct io_kiocb
*req
)
1784 __must_hold(&ctx
->uring_lock
)
1786 struct io_ring_ctx
*ctx
= req
->ctx
;
1787 struct io_defer_entry
*de
;
1789 u32 seq
= io_get_sequence(req
);
1791 /* Still need defer if there is pending req in defer list. */
1792 spin_lock(&ctx
->completion_lock
);
1793 if (!req_need_defer(req
, seq
) && list_empty_careful(&ctx
->defer_list
)) {
1794 spin_unlock(&ctx
->completion_lock
);
1796 ctx
->drain_active
= false;
1797 io_req_task_queue(req
);
1800 spin_unlock(&ctx
->completion_lock
);
1802 io_prep_async_link(req
);
1803 de
= kmalloc(sizeof(*de
), GFP_KERNEL
);
1806 io_req_defer_failed(req
, ret
);
1810 spin_lock(&ctx
->completion_lock
);
1811 if (!req_need_defer(req
, seq
) && list_empty(&ctx
->defer_list
)) {
1812 spin_unlock(&ctx
->completion_lock
);
1817 trace_io_uring_defer(req
);
1820 list_add_tail(&de
->list
, &ctx
->defer_list
);
1821 spin_unlock(&ctx
->completion_lock
);
1824 static bool io_assign_file(struct io_kiocb
*req
, const struct io_issue_def
*def
,
1825 unsigned int issue_flags
)
1827 if (req
->file
|| !def
->needs_file
)
1830 if (req
->flags
& REQ_F_FIXED_FILE
)
1831 req
->file
= io_file_get_fixed(req
, req
->cqe
.fd
, issue_flags
);
1833 req
->file
= io_file_get_normal(req
, req
->cqe
.fd
);
1838 static int io_issue_sqe(struct io_kiocb
*req
, unsigned int issue_flags
)
1840 const struct io_issue_def
*def
= &io_issue_defs
[req
->opcode
];
1841 const struct cred
*creds
= NULL
;
1844 if (unlikely(!io_assign_file(req
, def
, issue_flags
)))
1847 if (unlikely((req
->flags
& REQ_F_CREDS
) && req
->creds
!= current_cred()))
1848 creds
= override_creds(req
->creds
);
1850 if (!def
->audit_skip
)
1851 audit_uring_entry(req
->opcode
);
1853 ret
= def
->issue(req
, issue_flags
);
1855 if (!def
->audit_skip
)
1856 audit_uring_exit(!ret
, ret
);
1859 revert_creds(creds
);
1861 if (ret
== IOU_OK
) {
1862 if (issue_flags
& IO_URING_F_COMPLETE_DEFER
)
1863 io_req_complete_defer(req
);
1865 io_req_complete_post(req
, issue_flags
);
1866 } else if (ret
!= IOU_ISSUE_SKIP_COMPLETE
)
1869 /* If the op doesn't have a file, we're not polling for it */
1870 if ((req
->ctx
->flags
& IORING_SETUP_IOPOLL
) && def
->iopoll_queue
)
1871 io_iopoll_req_issued(req
, issue_flags
);
1876 int io_poll_issue(struct io_kiocb
*req
, struct io_tw_state
*ts
)
1878 io_tw_lock(req
->ctx
, ts
);
1879 return io_issue_sqe(req
, IO_URING_F_NONBLOCK
|IO_URING_F_MULTISHOT
|
1880 IO_URING_F_COMPLETE_DEFER
);
1883 struct io_wq_work
*io_wq_free_work(struct io_wq_work
*work
)
1885 struct io_kiocb
*req
= container_of(work
, struct io_kiocb
, work
);
1886 struct io_kiocb
*nxt
= NULL
;
1888 if (req_ref_put_and_test(req
)) {
1889 if (req
->flags
& IO_REQ_LINK_FLAGS
)
1890 nxt
= io_req_find_next(req
);
1893 return nxt
? &nxt
->work
: NULL
;
1896 void io_wq_submit_work(struct io_wq_work
*work
)
1898 struct io_kiocb
*req
= container_of(work
, struct io_kiocb
, work
);
1899 const struct io_issue_def
*def
= &io_issue_defs
[req
->opcode
];
1900 unsigned int issue_flags
= IO_URING_F_UNLOCKED
| IO_URING_F_IOWQ
;
1901 bool needs_poll
= false;
1902 int ret
= 0, err
= -ECANCELED
;
1904 /* one will be dropped by ->io_wq_free_work() after returning to io-wq */
1905 if (!(req
->flags
& REQ_F_REFCOUNT
))
1906 __io_req_set_refcount(req
, 2);
1910 io_arm_ltimeout(req
);
1912 /* either cancelled or io-wq is dying, so don't touch tctx->iowq */
1913 if (work
->flags
& IO_WQ_WORK_CANCEL
) {
1915 io_req_task_queue_fail(req
, err
);
1918 if (!io_assign_file(req
, def
, issue_flags
)) {
1920 work
->flags
|= IO_WQ_WORK_CANCEL
;
1924 if (req
->flags
& REQ_F_FORCE_ASYNC
) {
1925 bool opcode_poll
= def
->pollin
|| def
->pollout
;
1927 if (opcode_poll
&& file_can_poll(req
->file
)) {
1929 issue_flags
|= IO_URING_F_NONBLOCK
;
1934 ret
= io_issue_sqe(req
, issue_flags
);
1939 * If REQ_F_NOWAIT is set, then don't wait or retry with
1940 * poll. -EAGAIN is final for that case.
1942 if (req
->flags
& REQ_F_NOWAIT
)
1946 * We can get EAGAIN for iopolled IO even though we're
1947 * forcing a sync submission from here, since we can't
1948 * wait for request slots on the block side.
1951 if (!(req
->ctx
->flags
& IORING_SETUP_IOPOLL
))
1957 if (io_arm_poll_handler(req
, issue_flags
) == IO_APOLL_OK
)
1959 /* aborted or ready, in either case retry blocking */
1961 issue_flags
&= ~IO_URING_F_NONBLOCK
;
1964 /* avoid locking problems by failing it from a clean context */
1966 io_req_task_queue_fail(req
, ret
);
1969 inline struct file
*io_file_get_fixed(struct io_kiocb
*req
, int fd
,
1970 unsigned int issue_flags
)
1972 struct io_ring_ctx
*ctx
= req
->ctx
;
1973 struct io_fixed_file
*slot
;
1974 struct file
*file
= NULL
;
1976 io_ring_submit_lock(ctx
, issue_flags
);
1978 if (unlikely((unsigned int)fd
>= ctx
->nr_user_files
))
1980 fd
= array_index_nospec(fd
, ctx
->nr_user_files
);
1981 slot
= io_fixed_file_slot(&ctx
->file_table
, fd
);
1982 file
= io_slot_file(slot
);
1983 req
->flags
|= io_slot_flags(slot
);
1984 io_req_set_rsrc_node(req
, ctx
, 0);
1986 io_ring_submit_unlock(ctx
, issue_flags
);
1990 struct file
*io_file_get_normal(struct io_kiocb
*req
, int fd
)
1992 struct file
*file
= fget(fd
);
1994 trace_io_uring_file_get(req
, fd
);
1996 /* we don't allow fixed io_uring files */
1997 if (file
&& io_is_uring_fops(file
))
1998 io_req_track_inflight(req
);
2002 static void io_queue_async(struct io_kiocb
*req
, int ret
)
2003 __must_hold(&req
->ctx
->uring_lock
)
2005 struct io_kiocb
*linked_timeout
;
2007 if (ret
!= -EAGAIN
|| (req
->flags
& REQ_F_NOWAIT
)) {
2008 io_req_defer_failed(req
, ret
);
2012 linked_timeout
= io_prep_linked_timeout(req
);
2014 switch (io_arm_poll_handler(req
, 0)) {
2015 case IO_APOLL_READY
:
2016 io_kbuf_recycle(req
, 0);
2017 io_req_task_queue(req
);
2019 case IO_APOLL_ABORTED
:
2020 io_kbuf_recycle(req
, 0);
2021 io_queue_iowq(req
, NULL
);
2028 io_queue_linked_timeout(linked_timeout
);
2031 static inline void io_queue_sqe(struct io_kiocb
*req
)
2032 __must_hold(&req
->ctx
->uring_lock
)
2036 ret
= io_issue_sqe(req
, IO_URING_F_NONBLOCK
|IO_URING_F_COMPLETE_DEFER
);
2039 * We async punt it if the file wasn't marked NOWAIT, or if the file
2040 * doesn't support non-blocking read/write attempts
2043 io_arm_ltimeout(req
);
2045 io_queue_async(req
, ret
);
2048 static void io_queue_sqe_fallback(struct io_kiocb
*req
)
2049 __must_hold(&req
->ctx
->uring_lock
)
2051 if (unlikely(req
->flags
& REQ_F_FAIL
)) {
2053 * We don't submit, fail them all, for that replace hardlinks
2054 * with normal links. Extra REQ_F_LINK is tolerated.
2056 req
->flags
&= ~REQ_F_HARDLINK
;
2057 req
->flags
|= REQ_F_LINK
;
2058 io_req_defer_failed(req
, req
->cqe
.res
);
2060 int ret
= io_req_prep_async(req
);
2062 if (unlikely(ret
)) {
2063 io_req_defer_failed(req
, ret
);
2067 if (unlikely(req
->ctx
->drain_active
))
2070 io_queue_iowq(req
, NULL
);
2075 * Check SQE restrictions (opcode and flags).
2077 * Returns 'true' if SQE is allowed, 'false' otherwise.
2079 static inline bool io_check_restriction(struct io_ring_ctx
*ctx
,
2080 struct io_kiocb
*req
,
2081 unsigned int sqe_flags
)
2083 if (!test_bit(req
->opcode
, ctx
->restrictions
.sqe_op
))
2086 if ((sqe_flags
& ctx
->restrictions
.sqe_flags_required
) !=
2087 ctx
->restrictions
.sqe_flags_required
)
2090 if (sqe_flags
& ~(ctx
->restrictions
.sqe_flags_allowed
|
2091 ctx
->restrictions
.sqe_flags_required
))
2097 static void io_init_req_drain(struct io_kiocb
*req
)
2099 struct io_ring_ctx
*ctx
= req
->ctx
;
2100 struct io_kiocb
*head
= ctx
->submit_state
.link
.head
;
2102 ctx
->drain_active
= true;
2105 * If we need to drain a request in the middle of a link, drain
2106 * the head request and the next request/link after the current
2107 * link. Considering sequential execution of links,
2108 * REQ_F_IO_DRAIN will be maintained for every request of our
2111 head
->flags
|= REQ_F_IO_DRAIN
| REQ_F_FORCE_ASYNC
;
2112 ctx
->drain_next
= true;
2116 static int io_init_req(struct io_ring_ctx
*ctx
, struct io_kiocb
*req
,
2117 const struct io_uring_sqe
*sqe
)
2118 __must_hold(&ctx
->uring_lock
)
2120 const struct io_issue_def
*def
;
2121 unsigned int sqe_flags
;
2125 /* req is partially pre-initialised, see io_preinit_req() */
2126 req
->opcode
= opcode
= READ_ONCE(sqe
->opcode
);
2127 /* same numerical values with corresponding REQ_F_*, safe to copy */
2128 req
->flags
= sqe_flags
= READ_ONCE(sqe
->flags
);
2129 req
->cqe
.user_data
= READ_ONCE(sqe
->user_data
);
2131 req
->rsrc_node
= NULL
;
2132 req
->task
= current
;
2134 if (unlikely(opcode
>= IORING_OP_LAST
)) {
2138 def
= &io_issue_defs
[opcode
];
2139 if (unlikely(sqe_flags
& ~SQE_COMMON_FLAGS
)) {
2140 /* enforce forwards compatibility on users */
2141 if (sqe_flags
& ~SQE_VALID_FLAGS
)
2143 if (sqe_flags
& IOSQE_BUFFER_SELECT
) {
2144 if (!def
->buffer_select
)
2146 req
->buf_index
= READ_ONCE(sqe
->buf_group
);
2148 if (sqe_flags
& IOSQE_CQE_SKIP_SUCCESS
)
2149 ctx
->drain_disabled
= true;
2150 if (sqe_flags
& IOSQE_IO_DRAIN
) {
2151 if (ctx
->drain_disabled
)
2153 io_init_req_drain(req
);
2156 if (unlikely(ctx
->restricted
|| ctx
->drain_active
|| ctx
->drain_next
)) {
2157 if (ctx
->restricted
&& !io_check_restriction(ctx
, req
, sqe_flags
))
2159 /* knock it to the slow queue path, will be drained there */
2160 if (ctx
->drain_active
)
2161 req
->flags
|= REQ_F_FORCE_ASYNC
;
2162 /* if there is no link, we're at "next" request and need to drain */
2163 if (unlikely(ctx
->drain_next
) && !ctx
->submit_state
.link
.head
) {
2164 ctx
->drain_next
= false;
2165 ctx
->drain_active
= true;
2166 req
->flags
|= REQ_F_IO_DRAIN
| REQ_F_FORCE_ASYNC
;
2170 if (!def
->ioprio
&& sqe
->ioprio
)
2172 if (!def
->iopoll
&& (ctx
->flags
& IORING_SETUP_IOPOLL
))
2175 if (def
->needs_file
) {
2176 struct io_submit_state
*state
= &ctx
->submit_state
;
2178 req
->cqe
.fd
= READ_ONCE(sqe
->fd
);
2181 * Plug now if we have more than 2 IO left after this, and the
2182 * target is potentially a read/write to block based storage.
2184 if (state
->need_plug
&& def
->plug
) {
2185 state
->plug_started
= true;
2186 state
->need_plug
= false;
2187 blk_start_plug_nr_ios(&state
->plug
, state
->submit_nr
);
2191 personality
= READ_ONCE(sqe
->personality
);
2195 req
->creds
= xa_load(&ctx
->personalities
, personality
);
2198 get_cred(req
->creds
);
2199 ret
= security_uring_override_creds(req
->creds
);
2201 put_cred(req
->creds
);
2204 req
->flags
|= REQ_F_CREDS
;
2207 return def
->prep(req
, sqe
);
2210 static __cold
int io_submit_fail_init(const struct io_uring_sqe
*sqe
,
2211 struct io_kiocb
*req
, int ret
)
2213 struct io_ring_ctx
*ctx
= req
->ctx
;
2214 struct io_submit_link
*link
= &ctx
->submit_state
.link
;
2215 struct io_kiocb
*head
= link
->head
;
2217 trace_io_uring_req_failed(sqe
, req
, ret
);
2220 * Avoid breaking links in the middle as it renders links with SQPOLL
2221 * unusable. Instead of failing eagerly, continue assembling the link if
2222 * applicable and mark the head with REQ_F_FAIL. The link flushing code
2223 * should find the flag and handle the rest.
2225 req_fail_link_node(req
, ret
);
2226 if (head
&& !(head
->flags
& REQ_F_FAIL
))
2227 req_fail_link_node(head
, -ECANCELED
);
2229 if (!(req
->flags
& IO_REQ_LINK_FLAGS
)) {
2231 link
->last
->link
= req
;
2235 io_queue_sqe_fallback(req
);
2240 link
->last
->link
= req
;
2247 static inline int io_submit_sqe(struct io_ring_ctx
*ctx
, struct io_kiocb
*req
,
2248 const struct io_uring_sqe
*sqe
)
2249 __must_hold(&ctx
->uring_lock
)
2251 struct io_submit_link
*link
= &ctx
->submit_state
.link
;
2254 ret
= io_init_req(ctx
, req
, sqe
);
2256 return io_submit_fail_init(sqe
, req
, ret
);
2258 trace_io_uring_submit_req(req
);
2261 * If we already have a head request, queue this one for async
2262 * submittal once the head completes. If we don't have a head but
2263 * IOSQE_IO_LINK is set in the sqe, start a new head. This one will be
2264 * submitted sync once the chain is complete. If none of those
2265 * conditions are true (normal request), then just queue it.
2267 if (unlikely(link
->head
)) {
2268 ret
= io_req_prep_async(req
);
2270 return io_submit_fail_init(sqe
, req
, ret
);
2272 trace_io_uring_link(req
, link
->head
);
2273 link
->last
->link
= req
;
2276 if (req
->flags
& IO_REQ_LINK_FLAGS
)
2278 /* last request of the link, flush it */
2281 if (req
->flags
& (REQ_F_FORCE_ASYNC
| REQ_F_FAIL
))
2284 } else if (unlikely(req
->flags
& (IO_REQ_LINK_FLAGS
|
2285 REQ_F_FORCE_ASYNC
| REQ_F_FAIL
))) {
2286 if (req
->flags
& IO_REQ_LINK_FLAGS
) {
2291 io_queue_sqe_fallback(req
);
2301 * Batched submission is done, ensure local IO is flushed out.
2303 static void io_submit_state_end(struct io_ring_ctx
*ctx
)
2305 struct io_submit_state
*state
= &ctx
->submit_state
;
2307 if (unlikely(state
->link
.head
))
2308 io_queue_sqe_fallback(state
->link
.head
);
2309 /* flush only after queuing links as they can generate completions */
2310 io_submit_flush_completions(ctx
);
2311 if (state
->plug_started
)
2312 blk_finish_plug(&state
->plug
);
2316 * Start submission side cache.
2318 static void io_submit_state_start(struct io_submit_state
*state
,
2319 unsigned int max_ios
)
2321 state
->plug_started
= false;
2322 state
->need_plug
= max_ios
> 2;
2323 state
->submit_nr
= max_ios
;
2324 /* set only head, no need to init link_last in advance */
2325 state
->link
.head
= NULL
;
2328 static void io_commit_sqring(struct io_ring_ctx
*ctx
)
2330 struct io_rings
*rings
= ctx
->rings
;
2333 * Ensure any loads from the SQEs are done at this point,
2334 * since once we write the new head, the application could
2335 * write new data to them.
2337 smp_store_release(&rings
->sq
.head
, ctx
->cached_sq_head
);
2341 * Fetch an sqe, if one is available. Note this returns a pointer to memory
2342 * that is mapped by userspace. This means that care needs to be taken to
2343 * ensure that reads are stable, as we cannot rely on userspace always
2344 * being a good citizen. If members of the sqe are validated and then later
2345 * used, it's important that those reads are done through READ_ONCE() to
2346 * prevent a re-load down the line.
2348 static bool io_get_sqe(struct io_ring_ctx
*ctx
, const struct io_uring_sqe
**sqe
)
2350 unsigned mask
= ctx
->sq_entries
- 1;
2351 unsigned head
= ctx
->cached_sq_head
++ & mask
;
2353 if (!(ctx
->flags
& IORING_SETUP_NO_SQARRAY
)) {
2354 head
= READ_ONCE(ctx
->sq_array
[head
]);
2355 if (unlikely(head
>= ctx
->sq_entries
)) {
2356 /* drop invalid entries */
2357 spin_lock(&ctx
->completion_lock
);
2359 spin_unlock(&ctx
->completion_lock
);
2360 WRITE_ONCE(ctx
->rings
->sq_dropped
,
2361 READ_ONCE(ctx
->rings
->sq_dropped
) + 1);
2367 * The cached sq head (or cq tail) serves two purposes:
2369 * 1) allows us to batch the cost of updating the user visible
2371 * 2) allows the kernel side to track the head on its own, even
2372 * though the application is the one updating it.
2375 /* double index for 128-byte SQEs, twice as long */
2376 if (ctx
->flags
& IORING_SETUP_SQE128
)
2378 *sqe
= &ctx
->sq_sqes
[head
];
2382 int io_submit_sqes(struct io_ring_ctx
*ctx
, unsigned int nr
)
2383 __must_hold(&ctx
->uring_lock
)
2385 unsigned int entries
= io_sqring_entries(ctx
);
2389 if (unlikely(!entries
))
2391 /* make sure SQ entry isn't read before tail */
2392 ret
= left
= min(nr
, entries
);
2393 io_get_task_refs(left
);
2394 io_submit_state_start(&ctx
->submit_state
, left
);
2397 const struct io_uring_sqe
*sqe
;
2398 struct io_kiocb
*req
;
2400 if (unlikely(!io_alloc_req(ctx
, &req
)))
2402 if (unlikely(!io_get_sqe(ctx
, &sqe
))) {
2403 io_req_add_to_cache(req
, ctx
);
2408 * Continue submitting even for sqe failure if the
2409 * ring was setup with IORING_SETUP_SUBMIT_ALL
2411 if (unlikely(io_submit_sqe(ctx
, req
, sqe
)) &&
2412 !(ctx
->flags
& IORING_SETUP_SUBMIT_ALL
)) {
2418 if (unlikely(left
)) {
2420 /* try again if it submitted nothing and can't allocate a req */
2421 if (!ret
&& io_req_cache_empty(ctx
))
2423 current
->io_uring
->cached_refs
+= left
;
2426 io_submit_state_end(ctx
);
2427 /* Commit SQ ring head once we've consumed and submitted all SQEs */
2428 io_commit_sqring(ctx
);
2432 struct io_wait_queue
{
2433 struct wait_queue_entry wq
;
2434 struct io_ring_ctx
*ctx
;
2436 unsigned nr_timeouts
;
2440 static inline bool io_has_work(struct io_ring_ctx
*ctx
)
2442 return test_bit(IO_CHECK_CQ_OVERFLOW_BIT
, &ctx
->check_cq
) ||
2443 !llist_empty(&ctx
->work_llist
);
2446 static inline bool io_should_wake(struct io_wait_queue
*iowq
)
2448 struct io_ring_ctx
*ctx
= iowq
->ctx
;
2449 int dist
= READ_ONCE(ctx
->rings
->cq
.tail
) - (int) iowq
->cq_tail
;
2452 * Wake up if we have enough events, or if a timeout occurred since we
2453 * started waiting. For timeouts, we always want to return to userspace,
2454 * regardless of event count.
2456 return dist
>= 0 || atomic_read(&ctx
->cq_timeouts
) != iowq
->nr_timeouts
;
2459 static int io_wake_function(struct wait_queue_entry
*curr
, unsigned int mode
,
2460 int wake_flags
, void *key
)
2462 struct io_wait_queue
*iowq
= container_of(curr
, struct io_wait_queue
, wq
);
2465 * Cannot safely flush overflowed CQEs from here, ensure we wake up
2466 * the task, and the next invocation will do it.
2468 if (io_should_wake(iowq
) || io_has_work(iowq
->ctx
))
2469 return autoremove_wake_function(curr
, mode
, wake_flags
, key
);
2473 int io_run_task_work_sig(struct io_ring_ctx
*ctx
)
2475 if (!llist_empty(&ctx
->work_llist
)) {
2476 __set_current_state(TASK_RUNNING
);
2477 if (io_run_local_work(ctx
) > 0)
2480 if (io_run_task_work() > 0)
2482 if (task_sigpending(current
))
2487 static bool current_pending_io(void)
2489 struct io_uring_task
*tctx
= current
->io_uring
;
2493 return percpu_counter_read_positive(&tctx
->inflight
);
2496 /* when returns >0, the caller should retry */
2497 static inline int io_cqring_wait_schedule(struct io_ring_ctx
*ctx
,
2498 struct io_wait_queue
*iowq
)
2502 if (unlikely(READ_ONCE(ctx
->check_cq
)))
2504 if (unlikely(!llist_empty(&ctx
->work_llist
)))
2506 if (unlikely(test_thread_flag(TIF_NOTIFY_SIGNAL
)))
2508 if (unlikely(task_sigpending(current
)))
2510 if (unlikely(io_should_wake(iowq
)))
2514 * Mark us as being in io_wait if we have pending requests, so cpufreq
2515 * can take into account that the task is waiting for IO - turns out
2516 * to be important for low QD IO.
2518 io_wait
= current
->in_iowait
;
2519 if (current_pending_io())
2520 current
->in_iowait
= 1;
2522 if (iowq
->timeout
== KTIME_MAX
)
2524 else if (!schedule_hrtimeout(&iowq
->timeout
, HRTIMER_MODE_ABS
))
2526 current
->in_iowait
= io_wait
;
2531 * Wait until events become available, if we don't already have some. The
2532 * application must reap them itself, as they reside on the shared cq ring.
2534 static int io_cqring_wait(struct io_ring_ctx
*ctx
, int min_events
,
2535 const sigset_t __user
*sig
, size_t sigsz
,
2536 struct __kernel_timespec __user
*uts
)
2538 struct io_wait_queue iowq
;
2539 struct io_rings
*rings
= ctx
->rings
;
2542 if (!io_allowed_run_tw(ctx
))
2544 if (!llist_empty(&ctx
->work_llist
))
2545 io_run_local_work(ctx
);
2547 io_cqring_overflow_flush(ctx
);
2548 /* if user messes with these they will just get an early return */
2549 if (__io_cqring_events_user(ctx
) >= min_events
)
2553 #ifdef CONFIG_COMPAT
2554 if (in_compat_syscall())
2555 ret
= set_compat_user_sigmask((const compat_sigset_t __user
*)sig
,
2559 ret
= set_user_sigmask(sig
, sigsz
);
2565 init_waitqueue_func_entry(&iowq
.wq
, io_wake_function
);
2566 iowq
.wq
.private = current
;
2567 INIT_LIST_HEAD(&iowq
.wq
.entry
);
2569 iowq
.nr_timeouts
= atomic_read(&ctx
->cq_timeouts
);
2570 iowq
.cq_tail
= READ_ONCE(ctx
->rings
->cq
.head
) + min_events
;
2571 iowq
.timeout
= KTIME_MAX
;
2574 struct timespec64 ts
;
2576 if (get_timespec64(&ts
, uts
))
2578 iowq
.timeout
= ktime_add_ns(timespec64_to_ktime(ts
), ktime_get_ns());
2581 trace_io_uring_cqring_wait(ctx
, min_events
);
2583 unsigned long check_cq
;
2585 if (ctx
->flags
& IORING_SETUP_DEFER_TASKRUN
) {
2586 int nr_wait
= (int) iowq
.cq_tail
- READ_ONCE(ctx
->rings
->cq
.tail
);
2588 atomic_set(&ctx
->cq_wait_nr
, nr_wait
);
2589 set_current_state(TASK_INTERRUPTIBLE
);
2591 prepare_to_wait_exclusive(&ctx
->cq_wait
, &iowq
.wq
,
2592 TASK_INTERRUPTIBLE
);
2595 ret
= io_cqring_wait_schedule(ctx
, &iowq
);
2596 __set_current_state(TASK_RUNNING
);
2597 atomic_set(&ctx
->cq_wait_nr
, 0);
2602 * Run task_work after scheduling and before io_should_wake().
2603 * If we got woken because of task_work being processed, run it
2604 * now rather than let the caller do another wait loop.
2607 if (!llist_empty(&ctx
->work_llist
))
2608 io_run_local_work(ctx
);
2610 check_cq
= READ_ONCE(ctx
->check_cq
);
2611 if (unlikely(check_cq
)) {
2612 /* let the caller flush overflows, retry */
2613 if (check_cq
& BIT(IO_CHECK_CQ_OVERFLOW_BIT
))
2614 io_cqring_do_overflow_flush(ctx
);
2615 if (check_cq
& BIT(IO_CHECK_CQ_DROPPED_BIT
)) {
2621 if (io_should_wake(&iowq
)) {
2628 if (!(ctx
->flags
& IORING_SETUP_DEFER_TASKRUN
))
2629 finish_wait(&ctx
->cq_wait
, &iowq
.wq
);
2630 restore_saved_sigmask_unless(ret
== -EINTR
);
2632 return READ_ONCE(rings
->cq
.head
) == READ_ONCE(rings
->cq
.tail
) ? ret
: 0;
2635 static void io_mem_free(void *ptr
)
2640 folio_put(virt_to_folio(ptr
));
2643 static void io_pages_free(struct page
***pages
, int npages
)
2645 struct page
**page_array
;
2650 page_array
= *pages
;
2651 for (i
= 0; i
< npages
; i
++)
2652 unpin_user_page(page_array
[i
]);
2657 static void *__io_uaddr_map(struct page
***pages
, unsigned short *npages
,
2658 unsigned long uaddr
, size_t size
)
2660 struct page
**page_array
;
2661 unsigned int nr_pages
;
2666 if (uaddr
& (PAGE_SIZE
- 1) || !size
)
2667 return ERR_PTR(-EINVAL
);
2669 nr_pages
= (size
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2670 if (nr_pages
> USHRT_MAX
)
2671 return ERR_PTR(-EINVAL
);
2672 page_array
= kvmalloc_array(nr_pages
, sizeof(struct page
*), GFP_KERNEL
);
2674 return ERR_PTR(-ENOMEM
);
2676 ret
= pin_user_pages_fast(uaddr
, nr_pages
, FOLL_WRITE
| FOLL_LONGTERM
,
2678 if (ret
!= nr_pages
) {
2680 io_pages_free(&page_array
, ret
> 0 ? ret
: 0);
2681 return ret
< 0 ? ERR_PTR(ret
) : ERR_PTR(-EFAULT
);
2684 * Should be a single page. If the ring is small enough that we can
2685 * use a normal page, that is fine. If we need multiple pages, then
2686 * userspace should use a huge page. That's the only way to guarantee
2687 * that we get contigious memory, outside of just being lucky or
2688 * (currently) having low memory fragmentation.
2690 if (page_array
[0] != page_array
[ret
- 1])
2692 *pages
= page_array
;
2694 return page_to_virt(page_array
[0]);
2697 static void *io_rings_map(struct io_ring_ctx
*ctx
, unsigned long uaddr
,
2700 return __io_uaddr_map(&ctx
->ring_pages
, &ctx
->n_ring_pages
, uaddr
,
2704 static void *io_sqes_map(struct io_ring_ctx
*ctx
, unsigned long uaddr
,
2707 return __io_uaddr_map(&ctx
->sqe_pages
, &ctx
->n_sqe_pages
, uaddr
,
2711 static void io_rings_free(struct io_ring_ctx
*ctx
)
2713 if (!(ctx
->flags
& IORING_SETUP_NO_MMAP
)) {
2714 io_mem_free(ctx
->rings
);
2715 io_mem_free(ctx
->sq_sqes
);
2717 ctx
->sq_sqes
= NULL
;
2719 io_pages_free(&ctx
->ring_pages
, ctx
->n_ring_pages
);
2720 io_pages_free(&ctx
->sqe_pages
, ctx
->n_sqe_pages
);
2724 static void *io_mem_alloc(size_t size
)
2726 gfp_t gfp
= GFP_KERNEL_ACCOUNT
| __GFP_ZERO
| __GFP_NOWARN
| __GFP_COMP
;
2729 ret
= (void *) __get_free_pages(gfp
, get_order(size
));
2732 return ERR_PTR(-ENOMEM
);
2735 static unsigned long rings_size(struct io_ring_ctx
*ctx
, unsigned int sq_entries
,
2736 unsigned int cq_entries
, size_t *sq_offset
)
2738 struct io_rings
*rings
;
2739 size_t off
, sq_array_size
;
2741 off
= struct_size(rings
, cqes
, cq_entries
);
2742 if (off
== SIZE_MAX
)
2744 if (ctx
->flags
& IORING_SETUP_CQE32
) {
2745 if (check_shl_overflow(off
, 1, &off
))
2750 off
= ALIGN(off
, SMP_CACHE_BYTES
);
2755 if (ctx
->flags
& IORING_SETUP_NO_SQARRAY
) {
2757 *sq_offset
= SIZE_MAX
;
2764 sq_array_size
= array_size(sizeof(u32
), sq_entries
);
2765 if (sq_array_size
== SIZE_MAX
)
2768 if (check_add_overflow(off
, sq_array_size
, &off
))
2774 static int io_eventfd_register(struct io_ring_ctx
*ctx
, void __user
*arg
,
2775 unsigned int eventfd_async
)
2777 struct io_ev_fd
*ev_fd
;
2778 __s32 __user
*fds
= arg
;
2781 ev_fd
= rcu_dereference_protected(ctx
->io_ev_fd
,
2782 lockdep_is_held(&ctx
->uring_lock
));
2786 if (copy_from_user(&fd
, fds
, sizeof(*fds
)))
2789 ev_fd
= kmalloc(sizeof(*ev_fd
), GFP_KERNEL
);
2793 ev_fd
->cq_ev_fd
= eventfd_ctx_fdget(fd
);
2794 if (IS_ERR(ev_fd
->cq_ev_fd
)) {
2795 int ret
= PTR_ERR(ev_fd
->cq_ev_fd
);
2800 spin_lock(&ctx
->completion_lock
);
2801 ctx
->evfd_last_cq_tail
= ctx
->cached_cq_tail
;
2802 spin_unlock(&ctx
->completion_lock
);
2804 ev_fd
->eventfd_async
= eventfd_async
;
2805 ctx
->has_evfd
= true;
2806 rcu_assign_pointer(ctx
->io_ev_fd
, ev_fd
);
2807 atomic_set(&ev_fd
->refs
, 1);
2808 atomic_set(&ev_fd
->ops
, 0);
2812 static int io_eventfd_unregister(struct io_ring_ctx
*ctx
)
2814 struct io_ev_fd
*ev_fd
;
2816 ev_fd
= rcu_dereference_protected(ctx
->io_ev_fd
,
2817 lockdep_is_held(&ctx
->uring_lock
));
2819 ctx
->has_evfd
= false;
2820 rcu_assign_pointer(ctx
->io_ev_fd
, NULL
);
2821 if (!atomic_fetch_or(BIT(IO_EVENTFD_OP_FREE_BIT
), &ev_fd
->ops
))
2822 call_rcu(&ev_fd
->rcu
, io_eventfd_ops
);
2829 static void io_req_caches_free(struct io_ring_ctx
*ctx
)
2831 struct io_kiocb
*req
;
2834 mutex_lock(&ctx
->uring_lock
);
2835 io_flush_cached_locked_reqs(ctx
, &ctx
->submit_state
);
2837 while (!io_req_cache_empty(ctx
)) {
2838 req
= io_extract_req(ctx
);
2839 kmem_cache_free(req_cachep
, req
);
2843 percpu_ref_put_many(&ctx
->refs
, nr
);
2844 mutex_unlock(&ctx
->uring_lock
);
2847 static void io_rsrc_node_cache_free(struct io_cache_entry
*entry
)
2849 kfree(container_of(entry
, struct io_rsrc_node
, cache
));
2852 static __cold
void io_ring_ctx_free(struct io_ring_ctx
*ctx
)
2854 io_sq_thread_finish(ctx
);
2855 /* __io_rsrc_put_work() may need uring_lock to progress, wait w/o it */
2856 if (WARN_ON_ONCE(!list_empty(&ctx
->rsrc_ref_list
)))
2859 mutex_lock(&ctx
->uring_lock
);
2861 __io_sqe_buffers_unregister(ctx
);
2863 __io_sqe_files_unregister(ctx
);
2864 io_cqring_overflow_kill(ctx
);
2865 io_eventfd_unregister(ctx
);
2866 io_alloc_cache_free(&ctx
->apoll_cache
, io_apoll_cache_free
);
2867 io_alloc_cache_free(&ctx
->netmsg_cache
, io_netmsg_cache_free
);
2868 io_destroy_buffers(ctx
);
2869 mutex_unlock(&ctx
->uring_lock
);
2871 put_cred(ctx
->sq_creds
);
2872 if (ctx
->submitter_task
)
2873 put_task_struct(ctx
->submitter_task
);
2875 /* there are no registered resources left, nobody uses it */
2877 io_rsrc_node_destroy(ctx
, ctx
->rsrc_node
);
2879 WARN_ON_ONCE(!list_empty(&ctx
->rsrc_ref_list
));
2881 #if defined(CONFIG_UNIX)
2882 if (ctx
->ring_sock
) {
2883 ctx
->ring_sock
->file
= NULL
; /* so that iput() is called */
2884 sock_release(ctx
->ring_sock
);
2887 WARN_ON_ONCE(!list_empty(&ctx
->ltimeout_list
));
2889 io_alloc_cache_free(&ctx
->rsrc_node_cache
, io_rsrc_node_cache_free
);
2890 if (ctx
->mm_account
) {
2891 mmdrop(ctx
->mm_account
);
2892 ctx
->mm_account
= NULL
;
2896 percpu_ref_exit(&ctx
->refs
);
2897 free_uid(ctx
->user
);
2898 io_req_caches_free(ctx
);
2900 io_wq_put_hash(ctx
->hash_map
);
2901 kfree(ctx
->cancel_table
.hbs
);
2902 kfree(ctx
->cancel_table_locked
.hbs
);
2904 xa_destroy(&ctx
->io_bl_xa
);
2908 static __cold
void io_activate_pollwq_cb(struct callback_head
*cb
)
2910 struct io_ring_ctx
*ctx
= container_of(cb
, struct io_ring_ctx
,
2913 mutex_lock(&ctx
->uring_lock
);
2914 ctx
->poll_activated
= true;
2915 mutex_unlock(&ctx
->uring_lock
);
2918 * Wake ups for some events between start of polling and activation
2919 * might've been lost due to loose synchronisation.
2921 wake_up_all(&ctx
->poll_wq
);
2922 percpu_ref_put(&ctx
->refs
);
2925 static __cold
void io_activate_pollwq(struct io_ring_ctx
*ctx
)
2927 spin_lock(&ctx
->completion_lock
);
2928 /* already activated or in progress */
2929 if (ctx
->poll_activated
|| ctx
->poll_wq_task_work
.func
)
2931 if (WARN_ON_ONCE(!ctx
->task_complete
))
2933 if (!ctx
->submitter_task
)
2936 * with ->submitter_task only the submitter task completes requests, we
2937 * only need to sync with it, which is done by injecting a tw
2939 init_task_work(&ctx
->poll_wq_task_work
, io_activate_pollwq_cb
);
2940 percpu_ref_get(&ctx
->refs
);
2941 if (task_work_add(ctx
->submitter_task
, &ctx
->poll_wq_task_work
, TWA_SIGNAL
))
2942 percpu_ref_put(&ctx
->refs
);
2944 spin_unlock(&ctx
->completion_lock
);
2947 static __poll_t
io_uring_poll(struct file
*file
, poll_table
*wait
)
2949 struct io_ring_ctx
*ctx
= file
->private_data
;
2952 if (unlikely(!ctx
->poll_activated
))
2953 io_activate_pollwq(ctx
);
2955 poll_wait(file
, &ctx
->poll_wq
, wait
);
2957 * synchronizes with barrier from wq_has_sleeper call in
2961 if (!io_sqring_full(ctx
))
2962 mask
|= EPOLLOUT
| EPOLLWRNORM
;
2965 * Don't flush cqring overflow list here, just do a simple check.
2966 * Otherwise there could possible be ABBA deadlock:
2969 * lock(&ctx->uring_lock);
2971 * lock(&ctx->uring_lock);
2974 * Users may get EPOLLIN meanwhile seeing nothing in cqring, this
2975 * pushes them to do the flush.
2978 if (__io_cqring_events_user(ctx
) || io_has_work(ctx
))
2979 mask
|= EPOLLIN
| EPOLLRDNORM
;
2984 static int io_unregister_personality(struct io_ring_ctx
*ctx
, unsigned id
)
2986 const struct cred
*creds
;
2988 creds
= xa_erase(&ctx
->personalities
, id
);
2997 struct io_tctx_exit
{
2998 struct callback_head task_work
;
2999 struct completion completion
;
3000 struct io_ring_ctx
*ctx
;
3003 static __cold
void io_tctx_exit_cb(struct callback_head
*cb
)
3005 struct io_uring_task
*tctx
= current
->io_uring
;
3006 struct io_tctx_exit
*work
;
3008 work
= container_of(cb
, struct io_tctx_exit
, task_work
);
3010 * When @in_cancel, we're in cancellation and it's racy to remove the
3011 * node. It'll be removed by the end of cancellation, just ignore it.
3012 * tctx can be NULL if the queueing of this task_work raced with
3013 * work cancelation off the exec path.
3015 if (tctx
&& !atomic_read(&tctx
->in_cancel
))
3016 io_uring_del_tctx_node((unsigned long)work
->ctx
);
3017 complete(&work
->completion
);
3020 static __cold
bool io_cancel_ctx_cb(struct io_wq_work
*work
, void *data
)
3022 struct io_kiocb
*req
= container_of(work
, struct io_kiocb
, work
);
3024 return req
->ctx
== data
;
3027 static __cold
void io_ring_exit_work(struct work_struct
*work
)
3029 struct io_ring_ctx
*ctx
= container_of(work
, struct io_ring_ctx
, exit_work
);
3030 unsigned long timeout
= jiffies
+ HZ
* 60 * 5;
3031 unsigned long interval
= HZ
/ 20;
3032 struct io_tctx_exit exit
;
3033 struct io_tctx_node
*node
;
3037 * If we're doing polled IO and end up having requests being
3038 * submitted async (out-of-line), then completions can come in while
3039 * we're waiting for refs to drop. We need to reap these manually,
3040 * as nobody else will be looking for them.
3043 if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT
, &ctx
->check_cq
)) {
3044 mutex_lock(&ctx
->uring_lock
);
3045 io_cqring_overflow_kill(ctx
);
3046 mutex_unlock(&ctx
->uring_lock
);
3049 if (ctx
->flags
& IORING_SETUP_DEFER_TASKRUN
)
3050 io_move_task_work_from_local(ctx
);
3052 while (io_uring_try_cancel_requests(ctx
, NULL
, true))
3056 struct io_sq_data
*sqd
= ctx
->sq_data
;
3057 struct task_struct
*tsk
;
3059 io_sq_thread_park(sqd
);
3061 if (tsk
&& tsk
->io_uring
&& tsk
->io_uring
->io_wq
)
3062 io_wq_cancel_cb(tsk
->io_uring
->io_wq
,
3063 io_cancel_ctx_cb
, ctx
, true);
3064 io_sq_thread_unpark(sqd
);
3067 io_req_caches_free(ctx
);
3069 if (WARN_ON_ONCE(time_after(jiffies
, timeout
))) {
3070 /* there is little hope left, don't run it too often */
3074 * This is really an uninterruptible wait, as it has to be
3075 * complete. But it's also run from a kworker, which doesn't
3076 * take signals, so it's fine to make it interruptible. This
3077 * avoids scenarios where we knowingly can wait much longer
3078 * on completions, for example if someone does a SIGSTOP on
3079 * a task that needs to finish task_work to make this loop
3080 * complete. That's a synthetic situation that should not
3081 * cause a stuck task backtrace, and hence a potential panic
3082 * on stuck tasks if that is enabled.
3084 } while (!wait_for_completion_interruptible_timeout(&ctx
->ref_comp
, interval
));
3086 init_completion(&exit
.completion
);
3087 init_task_work(&exit
.task_work
, io_tctx_exit_cb
);
3090 * Some may use context even when all refs and requests have been put,
3091 * and they are free to do so while still holding uring_lock or
3092 * completion_lock, see io_req_task_submit(). Apart from other work,
3093 * this lock/unlock section also waits them to finish.
3095 mutex_lock(&ctx
->uring_lock
);
3096 while (!list_empty(&ctx
->tctx_list
)) {
3097 WARN_ON_ONCE(time_after(jiffies
, timeout
));
3099 node
= list_first_entry(&ctx
->tctx_list
, struct io_tctx_node
,
3101 /* don't spin on a single task if cancellation failed */
3102 list_rotate_left(&ctx
->tctx_list
);
3103 ret
= task_work_add(node
->task
, &exit
.task_work
, TWA_SIGNAL
);
3104 if (WARN_ON_ONCE(ret
))
3107 mutex_unlock(&ctx
->uring_lock
);
3109 * See comment above for
3110 * wait_for_completion_interruptible_timeout() on why this
3111 * wait is marked as interruptible.
3113 wait_for_completion_interruptible(&exit
.completion
);
3114 mutex_lock(&ctx
->uring_lock
);
3116 mutex_unlock(&ctx
->uring_lock
);
3117 spin_lock(&ctx
->completion_lock
);
3118 spin_unlock(&ctx
->completion_lock
);
3120 /* pairs with RCU read section in io_req_local_work_add() */
3121 if (ctx
->flags
& IORING_SETUP_DEFER_TASKRUN
)
3124 io_ring_ctx_free(ctx
);
3127 static __cold
void io_ring_ctx_wait_and_kill(struct io_ring_ctx
*ctx
)
3129 unsigned long index
;
3130 struct creds
*creds
;
3132 mutex_lock(&ctx
->uring_lock
);
3133 percpu_ref_kill(&ctx
->refs
);
3134 xa_for_each(&ctx
->personalities
, index
, creds
)
3135 io_unregister_personality(ctx
, index
);
3137 io_poll_remove_all(ctx
, NULL
, true);
3138 mutex_unlock(&ctx
->uring_lock
);
3141 * If we failed setting up the ctx, we might not have any rings
3142 * and therefore did not submit any requests
3145 io_kill_timeouts(ctx
, NULL
, true);
3147 flush_delayed_work(&ctx
->fallback_work
);
3149 INIT_WORK(&ctx
->exit_work
, io_ring_exit_work
);
3151 * Use system_unbound_wq to avoid spawning tons of event kworkers
3152 * if we're exiting a ton of rings at the same time. It just adds
3153 * noise and overhead, there's no discernable change in runtime
3154 * over using system_wq.
3156 queue_work(system_unbound_wq
, &ctx
->exit_work
);
3159 static int io_uring_release(struct inode
*inode
, struct file
*file
)
3161 struct io_ring_ctx
*ctx
= file
->private_data
;
3163 file
->private_data
= NULL
;
3164 io_ring_ctx_wait_and_kill(ctx
);
3168 struct io_task_cancel
{
3169 struct task_struct
*task
;
3173 static bool io_cancel_task_cb(struct io_wq_work
*work
, void *data
)
3175 struct io_kiocb
*req
= container_of(work
, struct io_kiocb
, work
);
3176 struct io_task_cancel
*cancel
= data
;
3178 return io_match_task_safe(req
, cancel
->task
, cancel
->all
);
3181 static __cold
bool io_cancel_defer_files(struct io_ring_ctx
*ctx
,
3182 struct task_struct
*task
,
3185 struct io_defer_entry
*de
;
3188 spin_lock(&ctx
->completion_lock
);
3189 list_for_each_entry_reverse(de
, &ctx
->defer_list
, list
) {
3190 if (io_match_task_safe(de
->req
, task
, cancel_all
)) {
3191 list_cut_position(&list
, &ctx
->defer_list
, &de
->list
);
3195 spin_unlock(&ctx
->completion_lock
);
3196 if (list_empty(&list
))
3199 while (!list_empty(&list
)) {
3200 de
= list_first_entry(&list
, struct io_defer_entry
, list
);
3201 list_del_init(&de
->list
);
3202 io_req_task_queue_fail(de
->req
, -ECANCELED
);
3208 static __cold
bool io_uring_try_cancel_iowq(struct io_ring_ctx
*ctx
)
3210 struct io_tctx_node
*node
;
3211 enum io_wq_cancel cret
;
3214 mutex_lock(&ctx
->uring_lock
);
3215 list_for_each_entry(node
, &ctx
->tctx_list
, ctx_node
) {
3216 struct io_uring_task
*tctx
= node
->task
->io_uring
;
3219 * io_wq will stay alive while we hold uring_lock, because it's
3220 * killed after ctx nodes, which requires to take the lock.
3222 if (!tctx
|| !tctx
->io_wq
)
3224 cret
= io_wq_cancel_cb(tctx
->io_wq
, io_cancel_ctx_cb
, ctx
, true);
3225 ret
|= (cret
!= IO_WQ_CANCEL_NOTFOUND
);
3227 mutex_unlock(&ctx
->uring_lock
);
3232 static __cold
bool io_uring_try_cancel_requests(struct io_ring_ctx
*ctx
,
3233 struct task_struct
*task
,
3236 struct io_task_cancel cancel
= { .task
= task
, .all
= cancel_all
, };
3237 struct io_uring_task
*tctx
= task
? task
->io_uring
: NULL
;
3238 enum io_wq_cancel cret
;
3241 /* set it so io_req_local_work_add() would wake us up */
3242 if (ctx
->flags
& IORING_SETUP_DEFER_TASKRUN
) {
3243 atomic_set(&ctx
->cq_wait_nr
, 1);
3247 /* failed during ring init, it couldn't have issued any requests */
3252 ret
|= io_uring_try_cancel_iowq(ctx
);
3253 } else if (tctx
&& tctx
->io_wq
) {
3255 * Cancels requests of all rings, not only @ctx, but
3256 * it's fine as the task is in exit/exec.
3258 cret
= io_wq_cancel_cb(tctx
->io_wq
, io_cancel_task_cb
,
3260 ret
|= (cret
!= IO_WQ_CANCEL_NOTFOUND
);
3263 /* SQPOLL thread does its own polling */
3264 if ((!(ctx
->flags
& IORING_SETUP_SQPOLL
) && cancel_all
) ||
3265 (ctx
->sq_data
&& ctx
->sq_data
->thread
== current
)) {
3266 while (!wq_list_empty(&ctx
->iopoll_list
)) {
3267 io_iopoll_try_reap_events(ctx
);
3273 if ((ctx
->flags
& IORING_SETUP_DEFER_TASKRUN
) &&
3274 io_allowed_defer_tw_run(ctx
))
3275 ret
|= io_run_local_work(ctx
) > 0;
3276 ret
|= io_cancel_defer_files(ctx
, task
, cancel_all
);
3277 mutex_lock(&ctx
->uring_lock
);
3278 ret
|= io_poll_remove_all(ctx
, task
, cancel_all
);
3279 mutex_unlock(&ctx
->uring_lock
);
3280 ret
|= io_kill_timeouts(ctx
, task
, cancel_all
);
3282 ret
|= io_run_task_work() > 0;
3286 static s64
tctx_inflight(struct io_uring_task
*tctx
, bool tracked
)
3289 return atomic_read(&tctx
->inflight_tracked
);
3290 return percpu_counter_sum(&tctx
->inflight
);
3294 * Find any io_uring ctx that this task has registered or done IO on, and cancel
3295 * requests. @sqd should be not-null IFF it's an SQPOLL thread cancellation.
3297 __cold
void io_uring_cancel_generic(bool cancel_all
, struct io_sq_data
*sqd
)
3299 struct io_uring_task
*tctx
= current
->io_uring
;
3300 struct io_ring_ctx
*ctx
;
3301 struct io_tctx_node
*node
;
3302 unsigned long index
;
3306 WARN_ON_ONCE(sqd
&& sqd
->thread
!= current
);
3308 if (!current
->io_uring
)
3311 io_wq_exit_start(tctx
->io_wq
);
3313 atomic_inc(&tctx
->in_cancel
);
3317 io_uring_drop_tctx_refs(current
);
3318 /* read completions before cancelations */
3319 inflight
= tctx_inflight(tctx
, !cancel_all
);
3324 xa_for_each(&tctx
->xa
, index
, node
) {
3325 /* sqpoll task will cancel all its requests */
3326 if (node
->ctx
->sq_data
)
3328 loop
|= io_uring_try_cancel_requests(node
->ctx
,
3329 current
, cancel_all
);
3332 list_for_each_entry(ctx
, &sqd
->ctx_list
, sqd_list
)
3333 loop
|= io_uring_try_cancel_requests(ctx
,
3343 prepare_to_wait(&tctx
->wait
, &wait
, TASK_INTERRUPTIBLE
);
3345 io_uring_drop_tctx_refs(current
);
3346 xa_for_each(&tctx
->xa
, index
, node
) {
3347 if (!llist_empty(&node
->ctx
->work_llist
)) {
3348 WARN_ON_ONCE(node
->ctx
->submitter_task
&&
3349 node
->ctx
->submitter_task
!= current
);
3354 * If we've seen completions, retry without waiting. This
3355 * avoids a race where a completion comes in before we did
3356 * prepare_to_wait().
3358 if (inflight
== tctx_inflight(tctx
, !cancel_all
))
3361 finish_wait(&tctx
->wait
, &wait
);
3364 io_uring_clean_tctx(tctx
);
3367 * We shouldn't run task_works after cancel, so just leave
3368 * ->in_cancel set for normal exit.
3370 atomic_dec(&tctx
->in_cancel
);
3371 /* for exec all current's requests should be gone, kill tctx */
3372 __io_uring_free(current
);
3376 void __io_uring_cancel(bool cancel_all
)
3378 io_uring_cancel_generic(cancel_all
, NULL
);
3381 static void *io_uring_validate_mmap_request(struct file
*file
,
3382 loff_t pgoff
, size_t sz
)
3384 struct io_ring_ctx
*ctx
= file
->private_data
;
3385 loff_t offset
= pgoff
<< PAGE_SHIFT
;
3389 /* Don't allow mmap if the ring was setup without it */
3390 if (ctx
->flags
& IORING_SETUP_NO_MMAP
)
3391 return ERR_PTR(-EINVAL
);
3393 switch (offset
& IORING_OFF_MMAP_MASK
) {
3394 case IORING_OFF_SQ_RING
:
3395 case IORING_OFF_CQ_RING
:
3398 case IORING_OFF_SQES
:
3401 case IORING_OFF_PBUF_RING
: {
3404 bgid
= (offset
& ~IORING_OFF_MMAP_MASK
) >> IORING_OFF_PBUF_SHIFT
;
3405 mutex_lock(&ctx
->uring_lock
);
3406 ptr
= io_pbuf_get_address(ctx
, bgid
);
3407 mutex_unlock(&ctx
->uring_lock
);
3409 return ERR_PTR(-EINVAL
);
3413 return ERR_PTR(-EINVAL
);
3416 page
= virt_to_head_page(ptr
);
3417 if (sz
> page_size(page
))
3418 return ERR_PTR(-EINVAL
);
3425 static __cold
int io_uring_mmap(struct file
*file
, struct vm_area_struct
*vma
)
3427 size_t sz
= vma
->vm_end
- vma
->vm_start
;
3431 ptr
= io_uring_validate_mmap_request(file
, vma
->vm_pgoff
, sz
);
3433 return PTR_ERR(ptr
);
3435 pfn
= virt_to_phys(ptr
) >> PAGE_SHIFT
;
3436 return remap_pfn_range(vma
, vma
->vm_start
, pfn
, sz
, vma
->vm_page_prot
);
3439 static unsigned long io_uring_mmu_get_unmapped_area(struct file
*filp
,
3440 unsigned long addr
, unsigned long len
,
3441 unsigned long pgoff
, unsigned long flags
)
3446 * Do not allow to map to user-provided address to avoid breaking the
3447 * aliasing rules. Userspace is not able to guess the offset address of
3448 * kernel kmalloc()ed memory area.
3453 ptr
= io_uring_validate_mmap_request(filp
, pgoff
, len
);
3458 * Some architectures have strong cache aliasing requirements.
3459 * For such architectures we need a coherent mapping which aliases
3460 * kernel memory *and* userspace memory. To achieve that:
3461 * - use a NULL file pointer to reference physical memory, and
3462 * - use the kernel virtual address of the shared io_uring context
3463 * (instead of the userspace-provided address, which has to be 0UL
3465 * - use the same pgoff which the get_unmapped_area() uses to
3466 * calculate the page colouring.
3467 * For architectures without such aliasing requirements, the
3468 * architecture will return any suitable mapping because addr is 0.
3471 flags
|= MAP_SHARED
;
3472 pgoff
= 0; /* has been translated to ptr above */
3474 addr
= (uintptr_t) ptr
;
3475 pgoff
= addr
>> PAGE_SHIFT
;
3479 return current
->mm
->get_unmapped_area(filp
, addr
, len
, pgoff
, flags
);
3482 #else /* !CONFIG_MMU */
3484 static int io_uring_mmap(struct file
*file
, struct vm_area_struct
*vma
)
3486 return is_nommu_shared_mapping(vma
->vm_flags
) ? 0 : -EINVAL
;
3489 static unsigned int io_uring_nommu_mmap_capabilities(struct file
*file
)
3491 return NOMMU_MAP_DIRECT
| NOMMU_MAP_READ
| NOMMU_MAP_WRITE
;
3494 static unsigned long io_uring_nommu_get_unmapped_area(struct file
*file
,
3495 unsigned long addr
, unsigned long len
,
3496 unsigned long pgoff
, unsigned long flags
)
3500 ptr
= io_uring_validate_mmap_request(file
, pgoff
, len
);
3502 return PTR_ERR(ptr
);
3504 return (unsigned long) ptr
;
3507 #endif /* !CONFIG_MMU */
3509 static int io_validate_ext_arg(unsigned flags
, const void __user
*argp
, size_t argsz
)
3511 if (flags
& IORING_ENTER_EXT_ARG
) {
3512 struct io_uring_getevents_arg arg
;
3514 if (argsz
!= sizeof(arg
))
3516 if (copy_from_user(&arg
, argp
, sizeof(arg
)))
3522 static int io_get_ext_arg(unsigned flags
, const void __user
*argp
, size_t *argsz
,
3523 struct __kernel_timespec __user
**ts
,
3524 const sigset_t __user
**sig
)
3526 struct io_uring_getevents_arg arg
;
3529 * If EXT_ARG isn't set, then we have no timespec and the argp pointer
3530 * is just a pointer to the sigset_t.
3532 if (!(flags
& IORING_ENTER_EXT_ARG
)) {
3533 *sig
= (const sigset_t __user
*) argp
;
3539 * EXT_ARG is set - ensure we agree on the size of it and copy in our
3540 * timespec and sigset_t pointers if good.
3542 if (*argsz
!= sizeof(arg
))
3544 if (copy_from_user(&arg
, argp
, sizeof(arg
)))
3548 *sig
= u64_to_user_ptr(arg
.sigmask
);
3549 *argsz
= arg
.sigmask_sz
;
3550 *ts
= u64_to_user_ptr(arg
.ts
);
3554 SYSCALL_DEFINE6(io_uring_enter
, unsigned int, fd
, u32
, to_submit
,
3555 u32
, min_complete
, u32
, flags
, const void __user
*, argp
,
3558 struct io_ring_ctx
*ctx
;
3562 if (unlikely(flags
& ~(IORING_ENTER_GETEVENTS
| IORING_ENTER_SQ_WAKEUP
|
3563 IORING_ENTER_SQ_WAIT
| IORING_ENTER_EXT_ARG
|
3564 IORING_ENTER_REGISTERED_RING
)))
3568 * Ring fd has been registered via IORING_REGISTER_RING_FDS, we
3569 * need only dereference our task private array to find it.
3571 if (flags
& IORING_ENTER_REGISTERED_RING
) {
3572 struct io_uring_task
*tctx
= current
->io_uring
;
3574 if (unlikely(!tctx
|| fd
>= IO_RINGFD_REG_MAX
))
3576 fd
= array_index_nospec(fd
, IO_RINGFD_REG_MAX
);
3577 f
.file
= tctx
->registered_rings
[fd
];
3579 if (unlikely(!f
.file
))
3583 if (unlikely(!f
.file
))
3586 if (unlikely(!io_is_uring_fops(f
.file
)))
3590 ctx
= f
.file
->private_data
;
3592 if (unlikely(ctx
->flags
& IORING_SETUP_R_DISABLED
))
3596 * For SQ polling, the thread will do all submissions and completions.
3597 * Just return the requested submit count, and wake the thread if
3601 if (ctx
->flags
& IORING_SETUP_SQPOLL
) {
3602 io_cqring_overflow_flush(ctx
);
3604 if (unlikely(ctx
->sq_data
->thread
== NULL
)) {
3608 if (flags
& IORING_ENTER_SQ_WAKEUP
)
3609 wake_up(&ctx
->sq_data
->wait
);
3610 if (flags
& IORING_ENTER_SQ_WAIT
)
3611 io_sqpoll_wait_sq(ctx
);
3614 } else if (to_submit
) {
3615 ret
= io_uring_add_tctx_node(ctx
);
3619 mutex_lock(&ctx
->uring_lock
);
3620 ret
= io_submit_sqes(ctx
, to_submit
);
3621 if (ret
!= to_submit
) {
3622 mutex_unlock(&ctx
->uring_lock
);
3625 if (flags
& IORING_ENTER_GETEVENTS
) {
3626 if (ctx
->syscall_iopoll
)
3629 * Ignore errors, we'll soon call io_cqring_wait() and
3630 * it should handle ownership problems if any.
3632 if (ctx
->flags
& IORING_SETUP_DEFER_TASKRUN
)
3633 (void)io_run_local_work_locked(ctx
);
3635 mutex_unlock(&ctx
->uring_lock
);
3638 if (flags
& IORING_ENTER_GETEVENTS
) {
3641 if (ctx
->syscall_iopoll
) {
3643 * We disallow the app entering submit/complete with
3644 * polling, but we still need to lock the ring to
3645 * prevent racing with polled issue that got punted to
3648 mutex_lock(&ctx
->uring_lock
);
3650 ret2
= io_validate_ext_arg(flags
, argp
, argsz
);
3651 if (likely(!ret2
)) {
3652 min_complete
= min(min_complete
,
3654 ret2
= io_iopoll_check(ctx
, min_complete
);
3656 mutex_unlock(&ctx
->uring_lock
);
3658 const sigset_t __user
*sig
;
3659 struct __kernel_timespec __user
*ts
;
3661 ret2
= io_get_ext_arg(flags
, argp
, &argsz
, &ts
, &sig
);
3662 if (likely(!ret2
)) {
3663 min_complete
= min(min_complete
,
3665 ret2
= io_cqring_wait(ctx
, min_complete
, sig
,
3674 * EBADR indicates that one or more CQE were dropped.
3675 * Once the user has been informed we can clear the bit
3676 * as they are obviously ok with those drops.
3678 if (unlikely(ret2
== -EBADR
))
3679 clear_bit(IO_CHECK_CQ_DROPPED_BIT
,
3688 static const struct file_operations io_uring_fops
= {
3689 .release
= io_uring_release
,
3690 .mmap
= io_uring_mmap
,
3692 .get_unmapped_area
= io_uring_nommu_get_unmapped_area
,
3693 .mmap_capabilities
= io_uring_nommu_mmap_capabilities
,
3695 .get_unmapped_area
= io_uring_mmu_get_unmapped_area
,
3697 .poll
= io_uring_poll
,
3698 #ifdef CONFIG_PROC_FS
3699 .show_fdinfo
= io_uring_show_fdinfo
,
3703 bool io_is_uring_fops(struct file
*file
)
3705 return file
->f_op
== &io_uring_fops
;
3708 static __cold
int io_allocate_scq_urings(struct io_ring_ctx
*ctx
,
3709 struct io_uring_params
*p
)
3711 struct io_rings
*rings
;
3712 size_t size
, sq_array_offset
;
3715 /* make sure these are sane, as we already accounted them */
3716 ctx
->sq_entries
= p
->sq_entries
;
3717 ctx
->cq_entries
= p
->cq_entries
;
3719 size
= rings_size(ctx
, p
->sq_entries
, p
->cq_entries
, &sq_array_offset
);
3720 if (size
== SIZE_MAX
)
3723 if (!(ctx
->flags
& IORING_SETUP_NO_MMAP
))
3724 rings
= io_mem_alloc(size
);
3726 rings
= io_rings_map(ctx
, p
->cq_off
.user_addr
, size
);
3729 return PTR_ERR(rings
);
3732 if (!(ctx
->flags
& IORING_SETUP_NO_SQARRAY
))
3733 ctx
->sq_array
= (u32
*)((char *)rings
+ sq_array_offset
);
3734 rings
->sq_ring_mask
= p
->sq_entries
- 1;
3735 rings
->cq_ring_mask
= p
->cq_entries
- 1;
3736 rings
->sq_ring_entries
= p
->sq_entries
;
3737 rings
->cq_ring_entries
= p
->cq_entries
;
3739 if (p
->flags
& IORING_SETUP_SQE128
)
3740 size
= array_size(2 * sizeof(struct io_uring_sqe
), p
->sq_entries
);
3742 size
= array_size(sizeof(struct io_uring_sqe
), p
->sq_entries
);
3743 if (size
== SIZE_MAX
) {
3748 if (!(ctx
->flags
& IORING_SETUP_NO_MMAP
))
3749 ptr
= io_mem_alloc(size
);
3751 ptr
= io_sqes_map(ctx
, p
->sq_off
.user_addr
, size
);
3755 return PTR_ERR(ptr
);
3762 static int io_uring_install_fd(struct file
*file
)
3766 fd
= get_unused_fd_flags(O_RDWR
| O_CLOEXEC
);
3769 fd_install(fd
, file
);
3774 * Allocate an anonymous fd, this is what constitutes the application
3775 * visible backing of an io_uring instance. The application mmaps this
3776 * fd to gain access to the SQ/CQ ring details. If UNIX sockets are enabled,
3777 * we have to tie this fd to a socket for file garbage collection purposes.
3779 static struct file
*io_uring_get_file(struct io_ring_ctx
*ctx
)
3782 #if defined(CONFIG_UNIX)
3785 ret
= sock_create_kern(&init_net
, PF_UNIX
, SOCK_RAW
, IPPROTO_IP
,
3788 return ERR_PTR(ret
);
3791 file
= anon_inode_getfile_secure("[io_uring]", &io_uring_fops
, ctx
,
3792 O_RDWR
| O_CLOEXEC
, NULL
);
3793 #if defined(CONFIG_UNIX)
3795 sock_release(ctx
->ring_sock
);
3796 ctx
->ring_sock
= NULL
;
3798 ctx
->ring_sock
->file
= file
;
3804 static __cold
int io_uring_create(unsigned entries
, struct io_uring_params
*p
,
3805 struct io_uring_params __user
*params
)
3807 struct io_ring_ctx
*ctx
;
3808 struct io_uring_task
*tctx
;
3814 if (entries
> IORING_MAX_ENTRIES
) {
3815 if (!(p
->flags
& IORING_SETUP_CLAMP
))
3817 entries
= IORING_MAX_ENTRIES
;
3820 if ((p
->flags
& IORING_SETUP_REGISTERED_FD_ONLY
)
3821 && !(p
->flags
& IORING_SETUP_NO_MMAP
))
3825 * Use twice as many entries for the CQ ring. It's possible for the
3826 * application to drive a higher depth than the size of the SQ ring,
3827 * since the sqes are only used at submission time. This allows for
3828 * some flexibility in overcommitting a bit. If the application has
3829 * set IORING_SETUP_CQSIZE, it will have passed in the desired number
3830 * of CQ ring entries manually.
3832 p
->sq_entries
= roundup_pow_of_two(entries
);
3833 if (p
->flags
& IORING_SETUP_CQSIZE
) {
3835 * If IORING_SETUP_CQSIZE is set, we do the same roundup
3836 * to a power-of-two, if it isn't already. We do NOT impose
3837 * any cq vs sq ring sizing.
3841 if (p
->cq_entries
> IORING_MAX_CQ_ENTRIES
) {
3842 if (!(p
->flags
& IORING_SETUP_CLAMP
))
3844 p
->cq_entries
= IORING_MAX_CQ_ENTRIES
;
3846 p
->cq_entries
= roundup_pow_of_two(p
->cq_entries
);
3847 if (p
->cq_entries
< p
->sq_entries
)
3850 p
->cq_entries
= 2 * p
->sq_entries
;
3853 ctx
= io_ring_ctx_alloc(p
);
3857 if ((ctx
->flags
& IORING_SETUP_DEFER_TASKRUN
) &&
3858 !(ctx
->flags
& IORING_SETUP_IOPOLL
) &&
3859 !(ctx
->flags
& IORING_SETUP_SQPOLL
))
3860 ctx
->task_complete
= true;
3862 if (ctx
->task_complete
|| (ctx
->flags
& IORING_SETUP_IOPOLL
))
3863 ctx
->lockless_cq
= true;
3866 * lazy poll_wq activation relies on ->task_complete for synchronisation
3867 * purposes, see io_activate_pollwq()
3869 if (!ctx
->task_complete
)
3870 ctx
->poll_activated
= true;
3873 * When SETUP_IOPOLL and SETUP_SQPOLL are both enabled, user
3874 * space applications don't need to do io completion events
3875 * polling again, they can rely on io_sq_thread to do polling
3876 * work, which can reduce cpu usage and uring_lock contention.
3878 if (ctx
->flags
& IORING_SETUP_IOPOLL
&&
3879 !(ctx
->flags
& IORING_SETUP_SQPOLL
))
3880 ctx
->syscall_iopoll
= 1;
3882 ctx
->compat
= in_compat_syscall();
3883 if (!ns_capable_noaudit(&init_user_ns
, CAP_IPC_LOCK
))
3884 ctx
->user
= get_uid(current_user());
3887 * For SQPOLL, we just need a wakeup, always. For !SQPOLL, if
3888 * COOP_TASKRUN is set, then IPIs are never needed by the app.
3891 if (ctx
->flags
& IORING_SETUP_SQPOLL
) {
3892 /* IPI related flags don't make sense with SQPOLL */
3893 if (ctx
->flags
& (IORING_SETUP_COOP_TASKRUN
|
3894 IORING_SETUP_TASKRUN_FLAG
|
3895 IORING_SETUP_DEFER_TASKRUN
))
3897 ctx
->notify_method
= TWA_SIGNAL_NO_IPI
;
3898 } else if (ctx
->flags
& IORING_SETUP_COOP_TASKRUN
) {
3899 ctx
->notify_method
= TWA_SIGNAL_NO_IPI
;
3901 if (ctx
->flags
& IORING_SETUP_TASKRUN_FLAG
&&
3902 !(ctx
->flags
& IORING_SETUP_DEFER_TASKRUN
))
3904 ctx
->notify_method
= TWA_SIGNAL
;
3908 * For DEFER_TASKRUN we require the completion task to be the same as the
3909 * submission task. This implies that there is only one submitter, so enforce
3912 if (ctx
->flags
& IORING_SETUP_DEFER_TASKRUN
&&
3913 !(ctx
->flags
& IORING_SETUP_SINGLE_ISSUER
)) {
3918 * This is just grabbed for accounting purposes. When a process exits,
3919 * the mm is exited and dropped before the files, hence we need to hang
3920 * on to this mm purely for the purposes of being able to unaccount
3921 * memory (locked/pinned vm). It's not used for anything else.
3923 mmgrab(current
->mm
);
3924 ctx
->mm_account
= current
->mm
;
3926 ret
= io_allocate_scq_urings(ctx
, p
);
3930 ret
= io_sq_offload_create(ctx
, p
);
3934 ret
= io_rsrc_init(ctx
);
3938 p
->sq_off
.head
= offsetof(struct io_rings
, sq
.head
);
3939 p
->sq_off
.tail
= offsetof(struct io_rings
, sq
.tail
);
3940 p
->sq_off
.ring_mask
= offsetof(struct io_rings
, sq_ring_mask
);
3941 p
->sq_off
.ring_entries
= offsetof(struct io_rings
, sq_ring_entries
);
3942 p
->sq_off
.flags
= offsetof(struct io_rings
, sq_flags
);
3943 p
->sq_off
.dropped
= offsetof(struct io_rings
, sq_dropped
);
3944 if (!(ctx
->flags
& IORING_SETUP_NO_SQARRAY
))
3945 p
->sq_off
.array
= (char *)ctx
->sq_array
- (char *)ctx
->rings
;
3946 p
->sq_off
.resv1
= 0;
3947 if (!(ctx
->flags
& IORING_SETUP_NO_MMAP
))
3948 p
->sq_off
.user_addr
= 0;
3950 p
->cq_off
.head
= offsetof(struct io_rings
, cq
.head
);
3951 p
->cq_off
.tail
= offsetof(struct io_rings
, cq
.tail
);
3952 p
->cq_off
.ring_mask
= offsetof(struct io_rings
, cq_ring_mask
);
3953 p
->cq_off
.ring_entries
= offsetof(struct io_rings
, cq_ring_entries
);
3954 p
->cq_off
.overflow
= offsetof(struct io_rings
, cq_overflow
);
3955 p
->cq_off
.cqes
= offsetof(struct io_rings
, cqes
);
3956 p
->cq_off
.flags
= offsetof(struct io_rings
, cq_flags
);
3957 p
->cq_off
.resv1
= 0;
3958 if (!(ctx
->flags
& IORING_SETUP_NO_MMAP
))
3959 p
->cq_off
.user_addr
= 0;
3961 p
->features
= IORING_FEAT_SINGLE_MMAP
| IORING_FEAT_NODROP
|
3962 IORING_FEAT_SUBMIT_STABLE
| IORING_FEAT_RW_CUR_POS
|
3963 IORING_FEAT_CUR_PERSONALITY
| IORING_FEAT_FAST_POLL
|
3964 IORING_FEAT_POLL_32BITS
| IORING_FEAT_SQPOLL_NONFIXED
|
3965 IORING_FEAT_EXT_ARG
| IORING_FEAT_NATIVE_WORKERS
|
3966 IORING_FEAT_RSRC_TAGS
| IORING_FEAT_CQE_SKIP
|
3967 IORING_FEAT_LINKED_FILE
| IORING_FEAT_REG_REG_RING
;
3969 if (copy_to_user(params
, p
, sizeof(*p
))) {
3974 if (ctx
->flags
& IORING_SETUP_SINGLE_ISSUER
3975 && !(ctx
->flags
& IORING_SETUP_R_DISABLED
))
3976 WRITE_ONCE(ctx
->submitter_task
, get_task_struct(current
));
3978 file
= io_uring_get_file(ctx
);
3980 ret
= PTR_ERR(file
);
3984 ret
= __io_uring_add_tctx_node(ctx
);
3987 tctx
= current
->io_uring
;
3990 * Install ring fd as the very last thing, so we don't risk someone
3991 * having closed it before we finish setup
3993 if (p
->flags
& IORING_SETUP_REGISTERED_FD_ONLY
)
3994 ret
= io_ring_add_registered_file(tctx
, file
, 0, IO_RINGFD_REG_MAX
);
3996 ret
= io_uring_install_fd(file
);
4000 trace_io_uring_create(ret
, ctx
, p
->sq_entries
, p
->cq_entries
, p
->flags
);
4003 io_ring_ctx_wait_and_kill(ctx
);
4011 * Sets up an aio uring context, and returns the fd. Applications asks for a
4012 * ring size, we return the actual sq/cq ring sizes (among other things) in the
4013 * params structure passed in.
4015 static long io_uring_setup(u32 entries
, struct io_uring_params __user
*params
)
4017 struct io_uring_params p
;
4020 if (copy_from_user(&p
, params
, sizeof(p
)))
4022 for (i
= 0; i
< ARRAY_SIZE(p
.resv
); i
++) {
4027 if (p
.flags
& ~(IORING_SETUP_IOPOLL
| IORING_SETUP_SQPOLL
|
4028 IORING_SETUP_SQ_AFF
| IORING_SETUP_CQSIZE
|
4029 IORING_SETUP_CLAMP
| IORING_SETUP_ATTACH_WQ
|
4030 IORING_SETUP_R_DISABLED
| IORING_SETUP_SUBMIT_ALL
|
4031 IORING_SETUP_COOP_TASKRUN
| IORING_SETUP_TASKRUN_FLAG
|
4032 IORING_SETUP_SQE128
| IORING_SETUP_CQE32
|
4033 IORING_SETUP_SINGLE_ISSUER
| IORING_SETUP_DEFER_TASKRUN
|
4034 IORING_SETUP_NO_MMAP
| IORING_SETUP_REGISTERED_FD_ONLY
|
4035 IORING_SETUP_NO_SQARRAY
))
4038 return io_uring_create(entries
, &p
, params
);
4041 SYSCALL_DEFINE2(io_uring_setup
, u32
, entries
,
4042 struct io_uring_params __user
*, params
)
4044 return io_uring_setup(entries
, params
);
4047 static __cold
int io_probe(struct io_ring_ctx
*ctx
, void __user
*arg
,
4050 struct io_uring_probe
*p
;
4054 size
= struct_size(p
, ops
, nr_args
);
4055 if (size
== SIZE_MAX
)
4057 p
= kzalloc(size
, GFP_KERNEL
);
4062 if (copy_from_user(p
, arg
, size
))
4065 if (memchr_inv(p
, 0, size
))
4068 p
->last_op
= IORING_OP_LAST
- 1;
4069 if (nr_args
> IORING_OP_LAST
)
4070 nr_args
= IORING_OP_LAST
;
4072 for (i
= 0; i
< nr_args
; i
++) {
4074 if (!io_issue_defs
[i
].not_supported
)
4075 p
->ops
[i
].flags
= IO_URING_OP_SUPPORTED
;
4080 if (copy_to_user(arg
, p
, size
))
4087 static int io_register_personality(struct io_ring_ctx
*ctx
)
4089 const struct cred
*creds
;
4093 creds
= get_current_cred();
4095 ret
= xa_alloc_cyclic(&ctx
->personalities
, &id
, (void *)creds
,
4096 XA_LIMIT(0, USHRT_MAX
), &ctx
->pers_next
, GFP_KERNEL
);
4104 static __cold
int io_register_restrictions(struct io_ring_ctx
*ctx
,
4105 void __user
*arg
, unsigned int nr_args
)
4107 struct io_uring_restriction
*res
;
4111 /* Restrictions allowed only if rings started disabled */
4112 if (!(ctx
->flags
& IORING_SETUP_R_DISABLED
))
4115 /* We allow only a single restrictions registration */
4116 if (ctx
->restrictions
.registered
)
4119 if (!arg
|| nr_args
> IORING_MAX_RESTRICTIONS
)
4122 size
= array_size(nr_args
, sizeof(*res
));
4123 if (size
== SIZE_MAX
)
4126 res
= memdup_user(arg
, size
);
4128 return PTR_ERR(res
);
4132 for (i
= 0; i
< nr_args
; i
++) {
4133 switch (res
[i
].opcode
) {
4134 case IORING_RESTRICTION_REGISTER_OP
:
4135 if (res
[i
].register_op
>= IORING_REGISTER_LAST
) {
4140 __set_bit(res
[i
].register_op
,
4141 ctx
->restrictions
.register_op
);
4143 case IORING_RESTRICTION_SQE_OP
:
4144 if (res
[i
].sqe_op
>= IORING_OP_LAST
) {
4149 __set_bit(res
[i
].sqe_op
, ctx
->restrictions
.sqe_op
);
4151 case IORING_RESTRICTION_SQE_FLAGS_ALLOWED
:
4152 ctx
->restrictions
.sqe_flags_allowed
= res
[i
].sqe_flags
;
4154 case IORING_RESTRICTION_SQE_FLAGS_REQUIRED
:
4155 ctx
->restrictions
.sqe_flags_required
= res
[i
].sqe_flags
;
4164 /* Reset all restrictions if an error happened */
4166 memset(&ctx
->restrictions
, 0, sizeof(ctx
->restrictions
));
4168 ctx
->restrictions
.registered
= true;
4174 static int io_register_enable_rings(struct io_ring_ctx
*ctx
)
4176 if (!(ctx
->flags
& IORING_SETUP_R_DISABLED
))
4179 if (ctx
->flags
& IORING_SETUP_SINGLE_ISSUER
&& !ctx
->submitter_task
) {
4180 WRITE_ONCE(ctx
->submitter_task
, get_task_struct(current
));
4182 * Lazy activation attempts would fail if it was polled before
4183 * submitter_task is set.
4185 if (wq_has_sleeper(&ctx
->poll_wq
))
4186 io_activate_pollwq(ctx
);
4189 if (ctx
->restrictions
.registered
)
4190 ctx
->restricted
= 1;
4192 ctx
->flags
&= ~IORING_SETUP_R_DISABLED
;
4193 if (ctx
->sq_data
&& wq_has_sleeper(&ctx
->sq_data
->wait
))
4194 wake_up(&ctx
->sq_data
->wait
);
4198 static __cold
int __io_register_iowq_aff(struct io_ring_ctx
*ctx
,
4199 cpumask_var_t new_mask
)
4203 if (!(ctx
->flags
& IORING_SETUP_SQPOLL
)) {
4204 ret
= io_wq_cpu_affinity(current
->io_uring
, new_mask
);
4206 mutex_unlock(&ctx
->uring_lock
);
4207 ret
= io_sqpoll_wq_cpu_affinity(ctx
, new_mask
);
4208 mutex_lock(&ctx
->uring_lock
);
4214 static __cold
int io_register_iowq_aff(struct io_ring_ctx
*ctx
,
4215 void __user
*arg
, unsigned len
)
4217 cpumask_var_t new_mask
;
4220 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
4223 cpumask_clear(new_mask
);
4224 if (len
> cpumask_size())
4225 len
= cpumask_size();
4227 if (in_compat_syscall()) {
4228 ret
= compat_get_bitmap(cpumask_bits(new_mask
),
4229 (const compat_ulong_t __user
*)arg
,
4230 len
* 8 /* CHAR_BIT */);
4232 ret
= copy_from_user(new_mask
, arg
, len
);
4236 free_cpumask_var(new_mask
);
4240 ret
= __io_register_iowq_aff(ctx
, new_mask
);
4241 free_cpumask_var(new_mask
);
4245 static __cold
int io_unregister_iowq_aff(struct io_ring_ctx
*ctx
)
4247 return __io_register_iowq_aff(ctx
, NULL
);
4250 static __cold
int io_register_iowq_max_workers(struct io_ring_ctx
*ctx
,
4252 __must_hold(&ctx
->uring_lock
)
4254 struct io_tctx_node
*node
;
4255 struct io_uring_task
*tctx
= NULL
;
4256 struct io_sq_data
*sqd
= NULL
;
4260 if (copy_from_user(new_count
, arg
, sizeof(new_count
)))
4262 for (i
= 0; i
< ARRAY_SIZE(new_count
); i
++)
4263 if (new_count
[i
] > INT_MAX
)
4266 if (ctx
->flags
& IORING_SETUP_SQPOLL
) {
4270 * Observe the correct sqd->lock -> ctx->uring_lock
4271 * ordering. Fine to drop uring_lock here, we hold
4274 refcount_inc(&sqd
->refs
);
4275 mutex_unlock(&ctx
->uring_lock
);
4276 mutex_lock(&sqd
->lock
);
4277 mutex_lock(&ctx
->uring_lock
);
4279 tctx
= sqd
->thread
->io_uring
;
4282 tctx
= current
->io_uring
;
4285 BUILD_BUG_ON(sizeof(new_count
) != sizeof(ctx
->iowq_limits
));
4287 for (i
= 0; i
< ARRAY_SIZE(new_count
); i
++)
4289 ctx
->iowq_limits
[i
] = new_count
[i
];
4290 ctx
->iowq_limits_set
= true;
4292 if (tctx
&& tctx
->io_wq
) {
4293 ret
= io_wq_max_workers(tctx
->io_wq
, new_count
);
4297 memset(new_count
, 0, sizeof(new_count
));
4301 mutex_unlock(&sqd
->lock
);
4302 io_put_sq_data(sqd
);
4305 if (copy_to_user(arg
, new_count
, sizeof(new_count
)))
4308 /* that's it for SQPOLL, only the SQPOLL task creates requests */
4312 /* now propagate the restriction to all registered users */
4313 list_for_each_entry(node
, &ctx
->tctx_list
, ctx_node
) {
4314 struct io_uring_task
*tctx
= node
->task
->io_uring
;
4316 if (WARN_ON_ONCE(!tctx
->io_wq
))
4319 for (i
= 0; i
< ARRAY_SIZE(new_count
); i
++)
4320 new_count
[i
] = ctx
->iowq_limits
[i
];
4321 /* ignore errors, it always returns zero anyway */
4322 (void)io_wq_max_workers(tctx
->io_wq
, new_count
);
4327 mutex_unlock(&sqd
->lock
);
4328 io_put_sq_data(sqd
);
4333 static int __io_uring_register(struct io_ring_ctx
*ctx
, unsigned opcode
,
4334 void __user
*arg
, unsigned nr_args
)
4335 __releases(ctx
->uring_lock
)
4336 __acquires(ctx
->uring_lock
)
4341 * We don't quiesce the refs for register anymore and so it can't be
4342 * dying as we're holding a file ref here.
4344 if (WARN_ON_ONCE(percpu_ref_is_dying(&ctx
->refs
)))
4347 if (ctx
->submitter_task
&& ctx
->submitter_task
!= current
)
4350 if (ctx
->restricted
) {
4351 opcode
= array_index_nospec(opcode
, IORING_REGISTER_LAST
);
4352 if (!test_bit(opcode
, ctx
->restrictions
.register_op
))
4357 case IORING_REGISTER_BUFFERS
:
4361 ret
= io_sqe_buffers_register(ctx
, arg
, nr_args
, NULL
);
4363 case IORING_UNREGISTER_BUFFERS
:
4367 ret
= io_sqe_buffers_unregister(ctx
);
4369 case IORING_REGISTER_FILES
:
4373 ret
= io_sqe_files_register(ctx
, arg
, nr_args
, NULL
);
4375 case IORING_UNREGISTER_FILES
:
4379 ret
= io_sqe_files_unregister(ctx
);
4381 case IORING_REGISTER_FILES_UPDATE
:
4382 ret
= io_register_files_update(ctx
, arg
, nr_args
);
4384 case IORING_REGISTER_EVENTFD
:
4388 ret
= io_eventfd_register(ctx
, arg
, 0);
4390 case IORING_REGISTER_EVENTFD_ASYNC
:
4394 ret
= io_eventfd_register(ctx
, arg
, 1);
4396 case IORING_UNREGISTER_EVENTFD
:
4400 ret
= io_eventfd_unregister(ctx
);
4402 case IORING_REGISTER_PROBE
:
4404 if (!arg
|| nr_args
> 256)
4406 ret
= io_probe(ctx
, arg
, nr_args
);
4408 case IORING_REGISTER_PERSONALITY
:
4412 ret
= io_register_personality(ctx
);
4414 case IORING_UNREGISTER_PERSONALITY
:
4418 ret
= io_unregister_personality(ctx
, nr_args
);
4420 case IORING_REGISTER_ENABLE_RINGS
:
4424 ret
= io_register_enable_rings(ctx
);
4426 case IORING_REGISTER_RESTRICTIONS
:
4427 ret
= io_register_restrictions(ctx
, arg
, nr_args
);
4429 case IORING_REGISTER_FILES2
:
4430 ret
= io_register_rsrc(ctx
, arg
, nr_args
, IORING_RSRC_FILE
);
4432 case IORING_REGISTER_FILES_UPDATE2
:
4433 ret
= io_register_rsrc_update(ctx
, arg
, nr_args
,
4436 case IORING_REGISTER_BUFFERS2
:
4437 ret
= io_register_rsrc(ctx
, arg
, nr_args
, IORING_RSRC_BUFFER
);
4439 case IORING_REGISTER_BUFFERS_UPDATE
:
4440 ret
= io_register_rsrc_update(ctx
, arg
, nr_args
,
4441 IORING_RSRC_BUFFER
);
4443 case IORING_REGISTER_IOWQ_AFF
:
4445 if (!arg
|| !nr_args
)
4447 ret
= io_register_iowq_aff(ctx
, arg
, nr_args
);
4449 case IORING_UNREGISTER_IOWQ_AFF
:
4453 ret
= io_unregister_iowq_aff(ctx
);
4455 case IORING_REGISTER_IOWQ_MAX_WORKERS
:
4457 if (!arg
|| nr_args
!= 2)
4459 ret
= io_register_iowq_max_workers(ctx
, arg
);
4461 case IORING_REGISTER_RING_FDS
:
4462 ret
= io_ringfd_register(ctx
, arg
, nr_args
);
4464 case IORING_UNREGISTER_RING_FDS
:
4465 ret
= io_ringfd_unregister(ctx
, arg
, nr_args
);
4467 case IORING_REGISTER_PBUF_RING
:
4469 if (!arg
|| nr_args
!= 1)
4471 ret
= io_register_pbuf_ring(ctx
, arg
);
4473 case IORING_UNREGISTER_PBUF_RING
:
4475 if (!arg
|| nr_args
!= 1)
4477 ret
= io_unregister_pbuf_ring(ctx
, arg
);
4479 case IORING_REGISTER_SYNC_CANCEL
:
4481 if (!arg
|| nr_args
!= 1)
4483 ret
= io_sync_cancel(ctx
, arg
);
4485 case IORING_REGISTER_FILE_ALLOC_RANGE
:
4487 if (!arg
|| nr_args
)
4489 ret
= io_register_file_alloc_range(ctx
, arg
);
4499 SYSCALL_DEFINE4(io_uring_register
, unsigned int, fd
, unsigned int, opcode
,
4500 void __user
*, arg
, unsigned int, nr_args
)
4502 struct io_ring_ctx
*ctx
;
4505 bool use_registered_ring
;
4507 use_registered_ring
= !!(opcode
& IORING_REGISTER_USE_REGISTERED_RING
);
4508 opcode
&= ~IORING_REGISTER_USE_REGISTERED_RING
;
4510 if (opcode
>= IORING_REGISTER_LAST
)
4513 if (use_registered_ring
) {
4515 * Ring fd has been registered via IORING_REGISTER_RING_FDS, we
4516 * need only dereference our task private array to find it.
4518 struct io_uring_task
*tctx
= current
->io_uring
;
4520 if (unlikely(!tctx
|| fd
>= IO_RINGFD_REG_MAX
))
4522 fd
= array_index_nospec(fd
, IO_RINGFD_REG_MAX
);
4523 f
.file
= tctx
->registered_rings
[fd
];
4525 if (unlikely(!f
.file
))
4529 if (unlikely(!f
.file
))
4532 if (!io_is_uring_fops(f
.file
))
4536 ctx
= f
.file
->private_data
;
4538 mutex_lock(&ctx
->uring_lock
);
4539 ret
= __io_uring_register(ctx
, opcode
, arg
, nr_args
);
4540 mutex_unlock(&ctx
->uring_lock
);
4541 trace_io_uring_register(ctx
, opcode
, ctx
->nr_user_files
, ctx
->nr_user_bufs
, ret
);
4547 static int __init
io_uring_init(void)
4549 #define __BUILD_BUG_VERIFY_OFFSET_SIZE(stype, eoffset, esize, ename) do { \
4550 BUILD_BUG_ON(offsetof(stype, ename) != eoffset); \
4551 BUILD_BUG_ON(sizeof_field(stype, ename) != esize); \
4554 #define BUILD_BUG_SQE_ELEM(eoffset, etype, ename) \
4555 __BUILD_BUG_VERIFY_OFFSET_SIZE(struct io_uring_sqe, eoffset, sizeof(etype), ename)
4556 #define BUILD_BUG_SQE_ELEM_SIZE(eoffset, esize, ename) \
4557 __BUILD_BUG_VERIFY_OFFSET_SIZE(struct io_uring_sqe, eoffset, esize, ename)
4558 BUILD_BUG_ON(sizeof(struct io_uring_sqe
) != 64);
4559 BUILD_BUG_SQE_ELEM(0, __u8
, opcode
);
4560 BUILD_BUG_SQE_ELEM(1, __u8
, flags
);
4561 BUILD_BUG_SQE_ELEM(2, __u16
, ioprio
);
4562 BUILD_BUG_SQE_ELEM(4, __s32
, fd
);
4563 BUILD_BUG_SQE_ELEM(8, __u64
, off
);
4564 BUILD_BUG_SQE_ELEM(8, __u64
, addr2
);
4565 BUILD_BUG_SQE_ELEM(8, __u32
, cmd_op
);
4566 BUILD_BUG_SQE_ELEM(12, __u32
, __pad1
);
4567 BUILD_BUG_SQE_ELEM(16, __u64
, addr
);
4568 BUILD_BUG_SQE_ELEM(16, __u64
, splice_off_in
);
4569 BUILD_BUG_SQE_ELEM(24, __u32
, len
);
4570 BUILD_BUG_SQE_ELEM(28, __kernel_rwf_t
, rw_flags
);
4571 BUILD_BUG_SQE_ELEM(28, /* compat */ int, rw_flags
);
4572 BUILD_BUG_SQE_ELEM(28, /* compat */ __u32
, rw_flags
);
4573 BUILD_BUG_SQE_ELEM(28, __u32
, fsync_flags
);
4574 BUILD_BUG_SQE_ELEM(28, /* compat */ __u16
, poll_events
);
4575 BUILD_BUG_SQE_ELEM(28, __u32
, poll32_events
);
4576 BUILD_BUG_SQE_ELEM(28, __u32
, sync_range_flags
);
4577 BUILD_BUG_SQE_ELEM(28, __u32
, msg_flags
);
4578 BUILD_BUG_SQE_ELEM(28, __u32
, timeout_flags
);
4579 BUILD_BUG_SQE_ELEM(28, __u32
, accept_flags
);
4580 BUILD_BUG_SQE_ELEM(28, __u32
, cancel_flags
);
4581 BUILD_BUG_SQE_ELEM(28, __u32
, open_flags
);
4582 BUILD_BUG_SQE_ELEM(28, __u32
, statx_flags
);
4583 BUILD_BUG_SQE_ELEM(28, __u32
, fadvise_advice
);
4584 BUILD_BUG_SQE_ELEM(28, __u32
, splice_flags
);
4585 BUILD_BUG_SQE_ELEM(28, __u32
, rename_flags
);
4586 BUILD_BUG_SQE_ELEM(28, __u32
, unlink_flags
);
4587 BUILD_BUG_SQE_ELEM(28, __u32
, hardlink_flags
);
4588 BUILD_BUG_SQE_ELEM(28, __u32
, xattr_flags
);
4589 BUILD_BUG_SQE_ELEM(28, __u32
, msg_ring_flags
);
4590 BUILD_BUG_SQE_ELEM(32, __u64
, user_data
);
4591 BUILD_BUG_SQE_ELEM(40, __u16
, buf_index
);
4592 BUILD_BUG_SQE_ELEM(40, __u16
, buf_group
);
4593 BUILD_BUG_SQE_ELEM(42, __u16
, personality
);
4594 BUILD_BUG_SQE_ELEM(44, __s32
, splice_fd_in
);
4595 BUILD_BUG_SQE_ELEM(44, __u32
, file_index
);
4596 BUILD_BUG_SQE_ELEM(44, __u16
, addr_len
);
4597 BUILD_BUG_SQE_ELEM(46, __u16
, __pad3
[0]);
4598 BUILD_BUG_SQE_ELEM(48, __u64
, addr3
);
4599 BUILD_BUG_SQE_ELEM_SIZE(48, 0, cmd
);
4600 BUILD_BUG_SQE_ELEM(56, __u64
, __pad2
);
4602 BUILD_BUG_ON(sizeof(struct io_uring_files_update
) !=
4603 sizeof(struct io_uring_rsrc_update
));
4604 BUILD_BUG_ON(sizeof(struct io_uring_rsrc_update
) >
4605 sizeof(struct io_uring_rsrc_update2
));
4607 /* ->buf_index is u16 */
4608 BUILD_BUG_ON(offsetof(struct io_uring_buf_ring
, bufs
) != 0);
4609 BUILD_BUG_ON(offsetof(struct io_uring_buf
, resv
) !=
4610 offsetof(struct io_uring_buf_ring
, tail
));
4612 /* should fit into one byte */
4613 BUILD_BUG_ON(SQE_VALID_FLAGS
>= (1 << 8));
4614 BUILD_BUG_ON(SQE_COMMON_FLAGS
>= (1 << 8));
4615 BUILD_BUG_ON((SQE_VALID_FLAGS
| SQE_COMMON_FLAGS
) != SQE_VALID_FLAGS
);
4617 BUILD_BUG_ON(__REQ_F_LAST_BIT
> 8 * sizeof(int));
4619 BUILD_BUG_ON(sizeof(atomic_t
) != sizeof(u32
));
4621 io_uring_optable_init();
4624 * Allow user copy in the per-command field, which starts after the
4625 * file in io_kiocb and until the opcode field. The openat2 handling
4626 * requires copying in user memory into the io_kiocb object in that
4627 * range, and HARDENED_USERCOPY will complain if we haven't
4628 * correctly annotated this range.
4630 req_cachep
= kmem_cache_create_usercopy("io_kiocb",
4631 sizeof(struct io_kiocb
), 0,
4632 SLAB_HWCACHE_ALIGN
| SLAB_PANIC
|
4633 SLAB_ACCOUNT
| SLAB_TYPESAFE_BY_RCU
,
4634 offsetof(struct io_kiocb
, cmd
.data
),
4635 sizeof_field(struct io_kiocb
, cmd
.data
), NULL
);
4639 __initcall(io_uring_init
);