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_cqring (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 <linux/compat.h>
47 #include <linux/refcount.h>
48 #include <linux/uio.h>
50 #include <linux/sched/signal.h>
52 #include <linux/file.h>
53 #include <linux/fdtable.h>
55 #include <linux/mman.h>
56 #include <linux/mmu_context.h>
57 #include <linux/percpu.h>
58 #include <linux/slab.h>
59 #include <linux/kthread.h>
60 #include <linux/blkdev.h>
61 #include <linux/bvec.h>
62 #include <linux/net.h>
64 #include <net/af_unix.h>
66 #include <linux/anon_inodes.h>
67 #include <linux/sched/mm.h>
68 #include <linux/uaccess.h>
69 #include <linux/nospec.h>
70 #include <linux/sizes.h>
71 #include <linux/hugetlb.h>
72 #include <linux/highmem.h>
74 #define CREATE_TRACE_POINTS
75 #include <trace/events/io_uring.h>
77 #include <uapi/linux/io_uring.h>
82 #define IORING_MAX_ENTRIES 32768
83 #define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES)
86 * Shift of 9 is 512 entries, or exactly one page on 64-bit archs
88 #define IORING_FILE_TABLE_SHIFT 9
89 #define IORING_MAX_FILES_TABLE (1U << IORING_FILE_TABLE_SHIFT)
90 #define IORING_FILE_TABLE_MASK (IORING_MAX_FILES_TABLE - 1)
91 #define IORING_MAX_FIXED_FILES (64 * IORING_MAX_FILES_TABLE)
94 u32 head ____cacheline_aligned_in_smp;
95 u32 tail ____cacheline_aligned_in_smp;
99 * This data is shared with the application through the mmap at offsets
100 * IORING_OFF_SQ_RING and IORING_OFF_CQ_RING.
102 * The offsets to the member fields are published through struct
103 * io_sqring_offsets when calling io_uring_setup.
107 * Head and tail offsets into the ring; the offsets need to be
108 * masked to get valid indices.
110 * The kernel controls head of the sq ring and the tail of the cq ring,
111 * and the application controls tail of the sq ring and the head of the
114 struct io_uring sq, cq;
116 * Bitmasks to apply to head and tail offsets (constant, equals
119 u32 sq_ring_mask, cq_ring_mask;
120 /* Ring sizes (constant, power of 2) */
121 u32 sq_ring_entries, cq_ring_entries;
123 * Number of invalid entries dropped by the kernel due to
124 * invalid index stored in array
126 * Written by the kernel, shouldn't be modified by the
127 * application (i.e. get number of "new events" by comparing to
130 * After a new SQ head value was read by the application this
131 * counter includes all submissions that were dropped reaching
132 * the new SQ head (and possibly more).
138 * Written by the kernel, shouldn't be modified by the
141 * The application needs a full memory barrier before checking
142 * for IORING_SQ_NEED_WAKEUP after updating the sq tail.
146 * Number of completion events lost because the queue was full;
147 * this should be avoided by the application by making sure
148 * there are not more requests pending than there is space in
149 * the completion queue.
151 * Written by the kernel, shouldn't be modified by the
152 * application (i.e. get number of "new events" by comparing to
155 * As completion events come in out of order this counter is not
156 * ordered with any other data.
160 * Ring buffer of completion events.
162 * The kernel writes completion events fresh every time they are
163 * produced, so the application is allowed to modify pending
166 struct io_uring_cqe cqes[] ____cacheline_aligned_in_smp;
169 struct io_mapped_ubuf {
172 struct bio_vec *bvec;
173 unsigned int nr_bvecs;
176 struct fixed_file_table {
182 struct percpu_ref refs;
183 } ____cacheline_aligned_in_smp;
189 bool cq_overflow_flushed;
193 * Ring buffer of indices into array of io_uring_sqe, which is
194 * mmapped by the application using the IORING_OFF_SQES offset.
196 * This indirection could e.g. be used to assign fixed
197 * io_uring_sqe entries to operations and only submit them to
198 * the queue when needed.
200 * The kernel modifies neither the indices array nor the entries
204 unsigned cached_sq_head;
207 unsigned sq_thread_idle;
208 unsigned cached_sq_dropped;
209 atomic_t cached_cq_overflow;
210 struct io_uring_sqe *sq_sqes;
212 struct list_head defer_list;
213 struct list_head timeout_list;
214 struct list_head cq_overflow_list;
216 wait_queue_head_t inflight_wait;
217 } ____cacheline_aligned_in_smp;
219 struct io_rings *rings;
223 struct task_struct *sqo_thread; /* if using sq thread polling */
224 struct mm_struct *sqo_mm;
225 wait_queue_head_t sqo_wait;
228 * If used, fixed file set. Writers must ensure that ->refs is dead,
229 * readers must ensure that ->refs is alive as long as the file* is
230 * used. Only updated through io_uring_register(2).
232 struct fixed_file_table *file_table;
233 unsigned nr_user_files;
235 /* if used, fixed mapped user buffers */
236 unsigned nr_user_bufs;
237 struct io_mapped_ubuf *user_bufs;
239 struct user_struct *user;
241 const struct cred *creds;
243 /* 0 is for ctx quiesce/reinit/free, 1 is for sqo_thread started */
244 struct completion *completions;
246 /* if all else fails... */
247 struct io_kiocb *fallback_req;
249 #if defined(CONFIG_UNIX)
250 struct socket *ring_sock;
254 unsigned cached_cq_tail;
257 atomic_t cq_timeouts;
258 struct wait_queue_head cq_wait;
259 struct fasync_struct *cq_fasync;
260 struct eventfd_ctx *cq_ev_fd;
261 } ____cacheline_aligned_in_smp;
264 struct mutex uring_lock;
265 wait_queue_head_t wait;
266 } ____cacheline_aligned_in_smp;
269 spinlock_t completion_lock;
270 bool poll_multi_file;
272 * ->poll_list is protected by the ctx->uring_lock for
273 * io_uring instances that don't use IORING_SETUP_SQPOLL.
274 * For SQPOLL, only the single threaded io_sq_thread() will
275 * manipulate the list, hence no extra locking is needed there.
277 struct list_head poll_list;
278 struct hlist_head *cancel_hash;
279 unsigned cancel_hash_bits;
281 spinlock_t inflight_lock;
282 struct list_head inflight_list;
283 } ____cacheline_aligned_in_smp;
287 * First field must be the file pointer in all the
288 * iocb unions! See also 'struct kiocb' in <linux/fs.h>
290 struct io_poll_iocb {
292 struct wait_queue_head *head;
296 struct wait_queue_entry wait;
299 struct io_timeout_data {
300 struct io_kiocb *req;
301 struct hrtimer timer;
302 struct timespec64 ts;
303 enum hrtimer_mode mode;
307 struct io_async_connect {
308 struct sockaddr_storage address;
311 struct io_async_msghdr {
312 struct iovec fast_iov[UIO_FASTIOV];
314 struct sockaddr __user *uaddr;
319 struct iovec fast_iov[UIO_FASTIOV];
325 struct io_async_ctx {
326 struct io_uring_sqe sqe;
328 struct io_async_rw rw;
329 struct io_async_msghdr msg;
330 struct io_async_connect connect;
331 struct io_timeout_data timeout;
336 * NOTE! Each of the iocb union members has the file pointer
337 * as the first entry in their struct definition. So you can
338 * access the file pointer through any of the sub-structs,
339 * or directly as just 'ki_filp' in this struct.
345 struct io_poll_iocb poll;
348 const struct io_uring_sqe *sqe;
349 struct io_async_ctx *io;
350 struct file *ring_file;
354 bool needs_fixed_file;
356 struct io_ring_ctx *ctx;
358 struct list_head list;
359 struct hlist_node hash_node;
361 struct list_head link_list;
364 #define REQ_F_NOWAIT 1 /* must not punt to workers */
365 #define REQ_F_IOPOLL_COMPLETED 2 /* polled IO has completed */
366 #define REQ_F_FIXED_FILE 4 /* ctx owns file */
367 #define REQ_F_LINK_NEXT 8 /* already grabbed next link */
368 #define REQ_F_IO_DRAIN 16 /* drain existing IO first */
369 #define REQ_F_IO_DRAINED 32 /* drain done */
370 #define REQ_F_LINK 64 /* linked sqes */
371 #define REQ_F_LINK_TIMEOUT 128 /* has linked timeout */
372 #define REQ_F_FAIL_LINK 256 /* fail rest of links */
373 #define REQ_F_DRAIN_LINK 512 /* link should be fully drained */
374 #define REQ_F_TIMEOUT 1024 /* timeout request */
375 #define REQ_F_ISREG 2048 /* regular file */
376 #define REQ_F_MUST_PUNT 4096 /* must be punted even for NONBLOCK */
377 #define REQ_F_TIMEOUT_NOSEQ 8192 /* no timeout sequence */
378 #define REQ_F_INFLIGHT 16384 /* on inflight list */
379 #define REQ_F_COMP_LOCKED 32768 /* completion under lock */
380 #define REQ_F_HARDLINK 65536 /* doesn't sever on completion < 0 */
385 struct list_head inflight_entry;
387 struct io_wq_work work;
390 #define IO_PLUG_THRESHOLD 2
391 #define IO_IOPOLL_BATCH 8
393 struct io_submit_state {
394 struct blk_plug plug;
397 * io_kiocb alloc cache
399 void *reqs[IO_IOPOLL_BATCH];
400 unsigned int free_reqs;
401 unsigned int cur_req;
404 * File reference cache
408 unsigned int has_refs;
409 unsigned int used_refs;
410 unsigned int ios_left;
413 static void io_wq_submit_work(struct io_wq_work **workptr);
414 static void io_cqring_fill_event(struct io_kiocb *req, long res);
415 static void __io_free_req(struct io_kiocb *req);
416 static void io_put_req(struct io_kiocb *req);
417 static void io_double_put_req(struct io_kiocb *req);
418 static void __io_double_put_req(struct io_kiocb *req);
419 static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req);
420 static void io_queue_linked_timeout(struct io_kiocb *req);
422 static struct kmem_cache *req_cachep;
424 static const struct file_operations io_uring_fops;
426 struct sock *io_uring_get_socket(struct file *file)
428 #if defined(CONFIG_UNIX)
429 if (file->f_op == &io_uring_fops) {
430 struct io_ring_ctx *ctx = file->private_data;
432 return ctx->ring_sock->sk;
437 EXPORT_SYMBOL(io_uring_get_socket);
439 static void io_ring_ctx_ref_free(struct percpu_ref *ref)
441 struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs);
443 complete(&ctx->completions[0]);
446 static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
448 struct io_ring_ctx *ctx;
451 ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
455 ctx->fallback_req = kmem_cache_alloc(req_cachep, GFP_KERNEL);
456 if (!ctx->fallback_req)
459 ctx->completions = kmalloc(2 * sizeof(struct completion), GFP_KERNEL);
460 if (!ctx->completions)
464 * Use 5 bits less than the max cq entries, that should give us around
465 * 32 entries per hash list if totally full and uniformly spread.
467 hash_bits = ilog2(p->cq_entries);
471 ctx->cancel_hash_bits = hash_bits;
472 ctx->cancel_hash = kmalloc((1U << hash_bits) * sizeof(struct hlist_head),
474 if (!ctx->cancel_hash)
476 __hash_init(ctx->cancel_hash, 1U << hash_bits);
478 if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free,
479 PERCPU_REF_ALLOW_REINIT, GFP_KERNEL))
482 ctx->flags = p->flags;
483 init_waitqueue_head(&ctx->cq_wait);
484 INIT_LIST_HEAD(&ctx->cq_overflow_list);
485 init_completion(&ctx->completions[0]);
486 init_completion(&ctx->completions[1]);
487 mutex_init(&ctx->uring_lock);
488 init_waitqueue_head(&ctx->wait);
489 spin_lock_init(&ctx->completion_lock);
490 INIT_LIST_HEAD(&ctx->poll_list);
491 INIT_LIST_HEAD(&ctx->defer_list);
492 INIT_LIST_HEAD(&ctx->timeout_list);
493 init_waitqueue_head(&ctx->inflight_wait);
494 spin_lock_init(&ctx->inflight_lock);
495 INIT_LIST_HEAD(&ctx->inflight_list);
498 if (ctx->fallback_req)
499 kmem_cache_free(req_cachep, ctx->fallback_req);
500 kfree(ctx->completions);
501 kfree(ctx->cancel_hash);
506 static inline bool __req_need_defer(struct io_kiocb *req)
508 struct io_ring_ctx *ctx = req->ctx;
510 return req->sequence != ctx->cached_cq_tail + ctx->cached_sq_dropped
511 + atomic_read(&ctx->cached_cq_overflow);
514 static inline bool req_need_defer(struct io_kiocb *req)
516 if ((req->flags & (REQ_F_IO_DRAIN|REQ_F_IO_DRAINED)) == REQ_F_IO_DRAIN)
517 return __req_need_defer(req);
522 static struct io_kiocb *io_get_deferred_req(struct io_ring_ctx *ctx)
524 struct io_kiocb *req;
526 req = list_first_entry_or_null(&ctx->defer_list, struct io_kiocb, list);
527 if (req && !req_need_defer(req)) {
528 list_del_init(&req->list);
535 static struct io_kiocb *io_get_timeout_req(struct io_ring_ctx *ctx)
537 struct io_kiocb *req;
539 req = list_first_entry_or_null(&ctx->timeout_list, struct io_kiocb, list);
541 if (req->flags & REQ_F_TIMEOUT_NOSEQ)
543 if (!__req_need_defer(req)) {
544 list_del_init(&req->list);
552 static void __io_commit_cqring(struct io_ring_ctx *ctx)
554 struct io_rings *rings = ctx->rings;
556 if (ctx->cached_cq_tail != READ_ONCE(rings->cq.tail)) {
557 /* order cqe stores with ring update */
558 smp_store_release(&rings->cq.tail, ctx->cached_cq_tail);
560 if (wq_has_sleeper(&ctx->cq_wait)) {
561 wake_up_interruptible(&ctx->cq_wait);
562 kill_fasync(&ctx->cq_fasync, SIGIO, POLL_IN);
567 static inline bool io_sqe_needs_user(const struct io_uring_sqe *sqe)
569 u8 opcode = READ_ONCE(sqe->opcode);
571 return !(opcode == IORING_OP_READ_FIXED ||
572 opcode == IORING_OP_WRITE_FIXED);
575 static inline bool io_prep_async_work(struct io_kiocb *req,
576 struct io_kiocb **link)
578 bool do_hashed = false;
581 switch (req->sqe->opcode) {
582 case IORING_OP_WRITEV:
583 case IORING_OP_WRITE_FIXED:
586 case IORING_OP_READV:
587 case IORING_OP_READ_FIXED:
588 case IORING_OP_SENDMSG:
589 case IORING_OP_RECVMSG:
590 case IORING_OP_ACCEPT:
591 case IORING_OP_POLL_ADD:
592 case IORING_OP_CONNECT:
594 * We know REQ_F_ISREG is not set on some of these
595 * opcodes, but this enables us to keep the check in
598 if (!(req->flags & REQ_F_ISREG))
599 req->work.flags |= IO_WQ_WORK_UNBOUND;
602 if (io_sqe_needs_user(req->sqe))
603 req->work.flags |= IO_WQ_WORK_NEEDS_USER;
606 *link = io_prep_linked_timeout(req);
610 static inline void io_queue_async_work(struct io_kiocb *req)
612 struct io_ring_ctx *ctx = req->ctx;
613 struct io_kiocb *link;
616 do_hashed = io_prep_async_work(req, &link);
618 trace_io_uring_queue_async_work(ctx, do_hashed, req, &req->work,
621 io_wq_enqueue(ctx->io_wq, &req->work);
623 io_wq_enqueue_hashed(ctx->io_wq, &req->work,
624 file_inode(req->file));
628 io_queue_linked_timeout(link);
631 static void io_kill_timeout(struct io_kiocb *req)
635 ret = hrtimer_try_to_cancel(&req->io->timeout.timer);
637 atomic_inc(&req->ctx->cq_timeouts);
638 list_del_init(&req->list);
639 io_cqring_fill_event(req, 0);
644 static void io_kill_timeouts(struct io_ring_ctx *ctx)
646 struct io_kiocb *req, *tmp;
648 spin_lock_irq(&ctx->completion_lock);
649 list_for_each_entry_safe(req, tmp, &ctx->timeout_list, list)
650 io_kill_timeout(req);
651 spin_unlock_irq(&ctx->completion_lock);
654 static void io_commit_cqring(struct io_ring_ctx *ctx)
656 struct io_kiocb *req;
658 while ((req = io_get_timeout_req(ctx)) != NULL)
659 io_kill_timeout(req);
661 __io_commit_cqring(ctx);
663 while ((req = io_get_deferred_req(ctx)) != NULL) {
664 req->flags |= REQ_F_IO_DRAINED;
665 io_queue_async_work(req);
669 static struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx)
671 struct io_rings *rings = ctx->rings;
674 tail = ctx->cached_cq_tail;
676 * writes to the cq entry need to come after reading head; the
677 * control dependency is enough as we're using WRITE_ONCE to
680 if (tail - READ_ONCE(rings->cq.head) == rings->cq_ring_entries)
683 ctx->cached_cq_tail++;
684 return &rings->cqes[tail & ctx->cq_mask];
687 static void io_cqring_ev_posted(struct io_ring_ctx *ctx)
689 if (waitqueue_active(&ctx->wait))
691 if (waitqueue_active(&ctx->sqo_wait))
692 wake_up(&ctx->sqo_wait);
694 eventfd_signal(ctx->cq_ev_fd, 1);
697 /* Returns true if there are no backlogged entries after the flush */
698 static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force)
700 struct io_rings *rings = ctx->rings;
701 struct io_uring_cqe *cqe;
702 struct io_kiocb *req;
707 if (list_empty_careful(&ctx->cq_overflow_list))
709 if ((ctx->cached_cq_tail - READ_ONCE(rings->cq.head) ==
710 rings->cq_ring_entries))
714 spin_lock_irqsave(&ctx->completion_lock, flags);
716 /* if force is set, the ring is going away. always drop after that */
718 ctx->cq_overflow_flushed = true;
721 while (!list_empty(&ctx->cq_overflow_list)) {
722 cqe = io_get_cqring(ctx);
726 req = list_first_entry(&ctx->cq_overflow_list, struct io_kiocb,
728 list_move(&req->list, &list);
730 WRITE_ONCE(cqe->user_data, req->user_data);
731 WRITE_ONCE(cqe->res, req->result);
732 WRITE_ONCE(cqe->flags, 0);
734 WRITE_ONCE(ctx->rings->cq_overflow,
735 atomic_inc_return(&ctx->cached_cq_overflow));
739 io_commit_cqring(ctx);
740 spin_unlock_irqrestore(&ctx->completion_lock, flags);
741 io_cqring_ev_posted(ctx);
743 while (!list_empty(&list)) {
744 req = list_first_entry(&list, struct io_kiocb, list);
745 list_del(&req->list);
752 static void io_cqring_fill_event(struct io_kiocb *req, long res)
754 struct io_ring_ctx *ctx = req->ctx;
755 struct io_uring_cqe *cqe;
757 trace_io_uring_complete(ctx, req->user_data, res);
760 * If we can't get a cq entry, userspace overflowed the
761 * submission (by quite a lot). Increment the overflow count in
764 cqe = io_get_cqring(ctx);
766 WRITE_ONCE(cqe->user_data, req->user_data);
767 WRITE_ONCE(cqe->res, res);
768 WRITE_ONCE(cqe->flags, 0);
769 } else if (ctx->cq_overflow_flushed) {
770 WRITE_ONCE(ctx->rings->cq_overflow,
771 atomic_inc_return(&ctx->cached_cq_overflow));
773 refcount_inc(&req->refs);
775 list_add_tail(&req->list, &ctx->cq_overflow_list);
779 static void io_cqring_add_event(struct io_kiocb *req, long res)
781 struct io_ring_ctx *ctx = req->ctx;
784 spin_lock_irqsave(&ctx->completion_lock, flags);
785 io_cqring_fill_event(req, res);
786 io_commit_cqring(ctx);
787 spin_unlock_irqrestore(&ctx->completion_lock, flags);
789 io_cqring_ev_posted(ctx);
792 static inline bool io_is_fallback_req(struct io_kiocb *req)
794 return req == (struct io_kiocb *)
795 ((unsigned long) req->ctx->fallback_req & ~1UL);
798 static struct io_kiocb *io_get_fallback_req(struct io_ring_ctx *ctx)
800 struct io_kiocb *req;
802 req = ctx->fallback_req;
803 if (!test_and_set_bit_lock(0, (unsigned long *) ctx->fallback_req))
809 static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx,
810 struct io_submit_state *state)
812 gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
813 struct io_kiocb *req;
815 if (!percpu_ref_tryget(&ctx->refs))
819 req = kmem_cache_alloc(req_cachep, gfp);
822 } else if (!state->free_reqs) {
826 sz = min_t(size_t, state->ios_left, ARRAY_SIZE(state->reqs));
827 ret = kmem_cache_alloc_bulk(req_cachep, gfp, sz, state->reqs);
830 * Bulk alloc is all-or-nothing. If we fail to get a batch,
831 * retry single alloc to be on the safe side.
833 if (unlikely(ret <= 0)) {
834 state->reqs[0] = kmem_cache_alloc(req_cachep, gfp);
839 state->free_reqs = ret - 1;
841 req = state->reqs[0];
843 req = state->reqs[state->cur_req];
850 req->ring_file = NULL;
854 /* one is dropped after submission, the other at completion */
855 refcount_set(&req->refs, 2);
857 INIT_IO_WORK(&req->work, io_wq_submit_work);
860 req = io_get_fallback_req(ctx);
863 percpu_ref_put(&ctx->refs);
867 static void io_free_req_many(struct io_ring_ctx *ctx, void **reqs, int *nr)
870 kmem_cache_free_bulk(req_cachep, *nr, reqs);
871 percpu_ref_put_many(&ctx->refs, *nr);
876 static void __io_free_req(struct io_kiocb *req)
878 struct io_ring_ctx *ctx = req->ctx;
882 if (req->file && !(req->flags & REQ_F_FIXED_FILE))
884 if (req->flags & REQ_F_INFLIGHT) {
887 spin_lock_irqsave(&ctx->inflight_lock, flags);
888 list_del(&req->inflight_entry);
889 if (waitqueue_active(&ctx->inflight_wait))
890 wake_up(&ctx->inflight_wait);
891 spin_unlock_irqrestore(&ctx->inflight_lock, flags);
893 percpu_ref_put(&ctx->refs);
894 if (likely(!io_is_fallback_req(req)))
895 kmem_cache_free(req_cachep, req);
897 clear_bit_unlock(0, (unsigned long *) ctx->fallback_req);
900 static bool io_link_cancel_timeout(struct io_kiocb *req)
902 struct io_ring_ctx *ctx = req->ctx;
905 ret = hrtimer_try_to_cancel(&req->io->timeout.timer);
907 io_cqring_fill_event(req, -ECANCELED);
908 io_commit_cqring(ctx);
909 req->flags &= ~REQ_F_LINK;
917 static void io_req_link_next(struct io_kiocb *req, struct io_kiocb **nxtptr)
919 struct io_ring_ctx *ctx = req->ctx;
920 bool wake_ev = false;
922 /* Already got next link */
923 if (req->flags & REQ_F_LINK_NEXT)
927 * The list should never be empty when we are called here. But could
928 * potentially happen if the chain is messed up, check to be on the
931 while (!list_empty(&req->link_list)) {
932 struct io_kiocb *nxt = list_first_entry(&req->link_list,
933 struct io_kiocb, link_list);
935 if (unlikely((req->flags & REQ_F_LINK_TIMEOUT) &&
936 (nxt->flags & REQ_F_TIMEOUT))) {
937 list_del_init(&nxt->link_list);
938 wake_ev |= io_link_cancel_timeout(nxt);
939 req->flags &= ~REQ_F_LINK_TIMEOUT;
943 list_del_init(&req->link_list);
944 if (!list_empty(&nxt->link_list))
945 nxt->flags |= REQ_F_LINK;
950 req->flags |= REQ_F_LINK_NEXT;
952 io_cqring_ev_posted(ctx);
956 * Called if REQ_F_LINK is set, and we fail the head request
958 static void io_fail_links(struct io_kiocb *req)
960 struct io_ring_ctx *ctx = req->ctx;
963 spin_lock_irqsave(&ctx->completion_lock, flags);
965 while (!list_empty(&req->link_list)) {
966 struct io_kiocb *link = list_first_entry(&req->link_list,
967 struct io_kiocb, link_list);
969 list_del_init(&link->link_list);
970 trace_io_uring_fail_link(req, link);
972 if ((req->flags & REQ_F_LINK_TIMEOUT) &&
973 link->sqe->opcode == IORING_OP_LINK_TIMEOUT) {
974 io_link_cancel_timeout(link);
976 io_cqring_fill_event(link, -ECANCELED);
977 __io_double_put_req(link);
979 req->flags &= ~REQ_F_LINK_TIMEOUT;
982 io_commit_cqring(ctx);
983 spin_unlock_irqrestore(&ctx->completion_lock, flags);
984 io_cqring_ev_posted(ctx);
987 static void io_req_find_next(struct io_kiocb *req, struct io_kiocb **nxt)
989 if (likely(!(req->flags & REQ_F_LINK)))
993 * If LINK is set, we have dependent requests in this chain. If we
994 * didn't fail this request, queue the first one up, moving any other
995 * dependencies to the next request. In case of failure, fail the rest
998 if (req->flags & REQ_F_FAIL_LINK) {
1000 } else if ((req->flags & (REQ_F_LINK_TIMEOUT | REQ_F_COMP_LOCKED)) ==
1001 REQ_F_LINK_TIMEOUT) {
1002 struct io_ring_ctx *ctx = req->ctx;
1003 unsigned long flags;
1006 * If this is a timeout link, we could be racing with the
1007 * timeout timer. Grab the completion lock for this case to
1008 * protect against that.
1010 spin_lock_irqsave(&ctx->completion_lock, flags);
1011 io_req_link_next(req, nxt);
1012 spin_unlock_irqrestore(&ctx->completion_lock, flags);
1014 io_req_link_next(req, nxt);
1018 static void io_free_req(struct io_kiocb *req)
1020 struct io_kiocb *nxt = NULL;
1022 io_req_find_next(req, &nxt);
1026 io_queue_async_work(nxt);
1030 * Drop reference to request, return next in chain (if there is one) if this
1031 * was the last reference to this request.
1033 __attribute__((nonnull))
1034 static void io_put_req_find_next(struct io_kiocb *req, struct io_kiocb **nxtptr)
1036 io_req_find_next(req, nxtptr);
1038 if (refcount_dec_and_test(&req->refs))
1042 static void io_put_req(struct io_kiocb *req)
1044 if (refcount_dec_and_test(&req->refs))
1049 * Must only be used if we don't need to care about links, usually from
1050 * within the completion handling itself.
1052 static void __io_double_put_req(struct io_kiocb *req)
1054 /* drop both submit and complete references */
1055 if (refcount_sub_and_test(2, &req->refs))
1059 static void io_double_put_req(struct io_kiocb *req)
1061 /* drop both submit and complete references */
1062 if (refcount_sub_and_test(2, &req->refs))
1066 static unsigned io_cqring_events(struct io_ring_ctx *ctx, bool noflush)
1068 struct io_rings *rings = ctx->rings;
1071 * noflush == true is from the waitqueue handler, just ensure we wake
1072 * up the task, and the next invocation will flush the entries. We
1073 * cannot safely to it from here.
1075 if (noflush && !list_empty(&ctx->cq_overflow_list))
1078 io_cqring_overflow_flush(ctx, false);
1080 /* See comment at the top of this file */
1082 return READ_ONCE(rings->cq.tail) - READ_ONCE(rings->cq.head);
1085 static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
1087 struct io_rings *rings = ctx->rings;
1089 /* make sure SQ entry isn't read before tail */
1090 return smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head;
1094 * Find and free completed poll iocbs
1096 static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
1097 struct list_head *done)
1099 void *reqs[IO_IOPOLL_BATCH];
1100 struct io_kiocb *req;
1104 while (!list_empty(done)) {
1105 req = list_first_entry(done, struct io_kiocb, list);
1106 list_del(&req->list);
1108 io_cqring_fill_event(req, req->result);
1111 if (refcount_dec_and_test(&req->refs)) {
1112 /* If we're not using fixed files, we have to pair the
1113 * completion part with the file put. Use regular
1114 * completions for those, only batch free for fixed
1115 * file and non-linked commands.
1117 if (((req->flags & (REQ_F_FIXED_FILE|REQ_F_LINK)) ==
1118 REQ_F_FIXED_FILE) && !io_is_fallback_req(req) &&
1120 reqs[to_free++] = req;
1121 if (to_free == ARRAY_SIZE(reqs))
1122 io_free_req_many(ctx, reqs, &to_free);
1129 io_commit_cqring(ctx);
1130 io_free_req_many(ctx, reqs, &to_free);
1133 static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
1136 struct io_kiocb *req, *tmp;
1142 * Only spin for completions if we don't have multiple devices hanging
1143 * off our complete list, and we're under the requested amount.
1145 spin = !ctx->poll_multi_file && *nr_events < min;
1148 list_for_each_entry_safe(req, tmp, &ctx->poll_list, list) {
1149 struct kiocb *kiocb = &req->rw;
1152 * Move completed entries to our local list. If we find a
1153 * request that requires polling, break out and complete
1154 * the done list first, if we have entries there.
1156 if (req->flags & REQ_F_IOPOLL_COMPLETED) {
1157 list_move_tail(&req->list, &done);
1160 if (!list_empty(&done))
1163 ret = kiocb->ki_filp->f_op->iopoll(kiocb, spin);
1172 if (!list_empty(&done))
1173 io_iopoll_complete(ctx, nr_events, &done);
1179 * Poll for a mininum of 'min' events. Note that if min == 0 we consider that a
1180 * non-spinning poll check - we'll still enter the driver poll loop, but only
1181 * as a non-spinning completion check.
1183 static int io_iopoll_getevents(struct io_ring_ctx *ctx, unsigned int *nr_events,
1186 while (!list_empty(&ctx->poll_list) && !need_resched()) {
1189 ret = io_do_iopoll(ctx, nr_events, min);
1192 if (!min || *nr_events >= min)
1200 * We can't just wait for polled events to come to us, we have to actively
1201 * find and complete them.
1203 static void io_iopoll_reap_events(struct io_ring_ctx *ctx)
1205 if (!(ctx->flags & IORING_SETUP_IOPOLL))
1208 mutex_lock(&ctx->uring_lock);
1209 while (!list_empty(&ctx->poll_list)) {
1210 unsigned int nr_events = 0;
1212 io_iopoll_getevents(ctx, &nr_events, 1);
1215 * Ensure we allow local-to-the-cpu processing to take place,
1216 * in this case we need to ensure that we reap all events.
1220 mutex_unlock(&ctx->uring_lock);
1223 static int __io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events,
1226 int iters = 0, ret = 0;
1232 * Don't enter poll loop if we already have events pending.
1233 * If we do, we can potentially be spinning for commands that
1234 * already triggered a CQE (eg in error).
1236 if (io_cqring_events(ctx, false))
1240 * If a submit got punted to a workqueue, we can have the
1241 * application entering polling for a command before it gets
1242 * issued. That app will hold the uring_lock for the duration
1243 * of the poll right here, so we need to take a breather every
1244 * now and then to ensure that the issue has a chance to add
1245 * the poll to the issued list. Otherwise we can spin here
1246 * forever, while the workqueue is stuck trying to acquire the
1249 if (!(++iters & 7)) {
1250 mutex_unlock(&ctx->uring_lock);
1251 mutex_lock(&ctx->uring_lock);
1254 if (*nr_events < min)
1255 tmin = min - *nr_events;
1257 ret = io_iopoll_getevents(ctx, nr_events, tmin);
1261 } while (min && !*nr_events && !need_resched());
1266 static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events,
1272 * We disallow the app entering submit/complete with polling, but we
1273 * still need to lock the ring to prevent racing with polled issue
1274 * that got punted to a workqueue.
1276 mutex_lock(&ctx->uring_lock);
1277 ret = __io_iopoll_check(ctx, nr_events, min);
1278 mutex_unlock(&ctx->uring_lock);
1282 static void kiocb_end_write(struct io_kiocb *req)
1285 * Tell lockdep we inherited freeze protection from submission
1288 if (req->flags & REQ_F_ISREG) {
1289 struct inode *inode = file_inode(req->file);
1291 __sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
1293 file_end_write(req->file);
1296 static inline void req_set_fail_links(struct io_kiocb *req)
1298 if ((req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) == REQ_F_LINK)
1299 req->flags |= REQ_F_FAIL_LINK;
1302 static void io_complete_rw_common(struct kiocb *kiocb, long res)
1304 struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
1306 if (kiocb->ki_flags & IOCB_WRITE)
1307 kiocb_end_write(req);
1309 if (res != req->result)
1310 req_set_fail_links(req);
1311 io_cqring_add_event(req, res);
1314 static void io_complete_rw(struct kiocb *kiocb, long res, long res2)
1316 struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
1318 io_complete_rw_common(kiocb, res);
1322 static struct io_kiocb *__io_complete_rw(struct kiocb *kiocb, long res)
1324 struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
1325 struct io_kiocb *nxt = NULL;
1327 io_complete_rw_common(kiocb, res);
1328 io_put_req_find_next(req, &nxt);
1333 static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2)
1335 struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
1337 if (kiocb->ki_flags & IOCB_WRITE)
1338 kiocb_end_write(req);
1340 if (res != req->result)
1341 req_set_fail_links(req);
1344 req->flags |= REQ_F_IOPOLL_COMPLETED;
1348 * After the iocb has been issued, it's safe to be found on the poll list.
1349 * Adding the kiocb to the list AFTER submission ensures that we don't
1350 * find it from a io_iopoll_getevents() thread before the issuer is done
1351 * accessing the kiocb cookie.
1353 static void io_iopoll_req_issued(struct io_kiocb *req)
1355 struct io_ring_ctx *ctx = req->ctx;
1358 * Track whether we have multiple files in our lists. This will impact
1359 * how we do polling eventually, not spinning if we're on potentially
1360 * different devices.
1362 if (list_empty(&ctx->poll_list)) {
1363 ctx->poll_multi_file = false;
1364 } else if (!ctx->poll_multi_file) {
1365 struct io_kiocb *list_req;
1367 list_req = list_first_entry(&ctx->poll_list, struct io_kiocb,
1369 if (list_req->rw.ki_filp != req->rw.ki_filp)
1370 ctx->poll_multi_file = true;
1374 * For fast devices, IO may have already completed. If it has, add
1375 * it to the front so we find it first.
1377 if (req->flags & REQ_F_IOPOLL_COMPLETED)
1378 list_add(&req->list, &ctx->poll_list);
1380 list_add_tail(&req->list, &ctx->poll_list);
1383 static void io_file_put(struct io_submit_state *state)
1386 int diff = state->has_refs - state->used_refs;
1389 fput_many(state->file, diff);
1395 * Get as many references to a file as we have IOs left in this submission,
1396 * assuming most submissions are for one file, or at least that each file
1397 * has more than one submission.
1399 static struct file *io_file_get(struct io_submit_state *state, int fd)
1405 if (state->fd == fd) {
1412 state->file = fget_many(fd, state->ios_left);
1417 state->has_refs = state->ios_left;
1418 state->used_refs = 1;
1424 * If we tracked the file through the SCM inflight mechanism, we could support
1425 * any file. For now, just ensure that anything potentially problematic is done
1428 static bool io_file_supports_async(struct file *file)
1430 umode_t mode = file_inode(file)->i_mode;
1432 if (S_ISBLK(mode) || S_ISCHR(mode))
1434 if (S_ISREG(mode) && file->f_op != &io_uring_fops)
1440 static int io_prep_rw(struct io_kiocb *req, bool force_nonblock)
1442 const struct io_uring_sqe *sqe = req->sqe;
1443 struct io_ring_ctx *ctx = req->ctx;
1444 struct kiocb *kiocb = &req->rw;
1451 if (S_ISREG(file_inode(req->file)->i_mode))
1452 req->flags |= REQ_F_ISREG;
1454 kiocb->ki_pos = READ_ONCE(sqe->off);
1455 kiocb->ki_flags = iocb_flags(kiocb->ki_filp);
1456 kiocb->ki_hint = ki_hint_validate(file_write_hint(kiocb->ki_filp));
1458 ioprio = READ_ONCE(sqe->ioprio);
1460 ret = ioprio_check_cap(ioprio);
1464 kiocb->ki_ioprio = ioprio;
1466 kiocb->ki_ioprio = get_current_ioprio();
1468 ret = kiocb_set_rw_flags(kiocb, READ_ONCE(sqe->rw_flags));
1472 /* don't allow async punt if RWF_NOWAIT was requested */
1473 if ((kiocb->ki_flags & IOCB_NOWAIT) ||
1474 (req->file->f_flags & O_NONBLOCK))
1475 req->flags |= REQ_F_NOWAIT;
1478 kiocb->ki_flags |= IOCB_NOWAIT;
1480 if (ctx->flags & IORING_SETUP_IOPOLL) {
1481 if (!(kiocb->ki_flags & IOCB_DIRECT) ||
1482 !kiocb->ki_filp->f_op->iopoll)
1485 kiocb->ki_flags |= IOCB_HIPRI;
1486 kiocb->ki_complete = io_complete_rw_iopoll;
1489 if (kiocb->ki_flags & IOCB_HIPRI)
1491 kiocb->ki_complete = io_complete_rw;
1496 static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
1502 case -ERESTARTNOINTR:
1503 case -ERESTARTNOHAND:
1504 case -ERESTART_RESTARTBLOCK:
1506 * We can't just restart the syscall, since previously
1507 * submitted sqes may already be in progress. Just fail this
1513 kiocb->ki_complete(kiocb, ret, 0);
1517 static void kiocb_done(struct kiocb *kiocb, ssize_t ret, struct io_kiocb **nxt,
1520 if (in_async && ret >= 0 && kiocb->ki_complete == io_complete_rw)
1521 *nxt = __io_complete_rw(kiocb, ret);
1523 io_rw_done(kiocb, ret);
1526 static ssize_t io_import_fixed(struct io_ring_ctx *ctx, int rw,
1527 const struct io_uring_sqe *sqe,
1528 struct iov_iter *iter)
1530 size_t len = READ_ONCE(sqe->len);
1531 struct io_mapped_ubuf *imu;
1532 unsigned index, buf_index;
1536 /* attempt to use fixed buffers without having provided iovecs */
1537 if (unlikely(!ctx->user_bufs))
1540 buf_index = READ_ONCE(sqe->buf_index);
1541 if (unlikely(buf_index >= ctx->nr_user_bufs))
1544 index = array_index_nospec(buf_index, ctx->nr_user_bufs);
1545 imu = &ctx->user_bufs[index];
1546 buf_addr = READ_ONCE(sqe->addr);
1549 if (buf_addr + len < buf_addr)
1551 /* not inside the mapped region */
1552 if (buf_addr < imu->ubuf || buf_addr + len > imu->ubuf + imu->len)
1556 * May not be a start of buffer, set size appropriately
1557 * and advance us to the beginning.
1559 offset = buf_addr - imu->ubuf;
1560 iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len);
1564 * Don't use iov_iter_advance() here, as it's really slow for
1565 * using the latter parts of a big fixed buffer - it iterates
1566 * over each segment manually. We can cheat a bit here, because
1569 * 1) it's a BVEC iter, we set it up
1570 * 2) all bvecs are PAGE_SIZE in size, except potentially the
1571 * first and last bvec
1573 * So just find our index, and adjust the iterator afterwards.
1574 * If the offset is within the first bvec (or the whole first
1575 * bvec, just use iov_iter_advance(). This makes it easier
1576 * since we can just skip the first segment, which may not
1577 * be PAGE_SIZE aligned.
1579 const struct bio_vec *bvec = imu->bvec;
1581 if (offset <= bvec->bv_len) {
1582 iov_iter_advance(iter, offset);
1584 unsigned long seg_skip;
1586 /* skip first vec */
1587 offset -= bvec->bv_len;
1588 seg_skip = 1 + (offset >> PAGE_SHIFT);
1590 iter->bvec = bvec + seg_skip;
1591 iter->nr_segs -= seg_skip;
1592 iter->count -= bvec->bv_len + offset;
1593 iter->iov_offset = offset & ~PAGE_MASK;
1600 static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
1601 struct iovec **iovec, struct iov_iter *iter)
1603 const struct io_uring_sqe *sqe = req->sqe;
1604 void __user *buf = u64_to_user_ptr(READ_ONCE(sqe->addr));
1605 size_t sqe_len = READ_ONCE(sqe->len);
1609 * We're reading ->opcode for the second time, but the first read
1610 * doesn't care whether it's _FIXED or not, so it doesn't matter
1611 * whether ->opcode changes concurrently. The first read does care
1612 * about whether it is a READ or a WRITE, so we don't trust this read
1613 * for that purpose and instead let the caller pass in the read/write
1616 opcode = READ_ONCE(sqe->opcode);
1617 if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
1619 return io_import_fixed(req->ctx, rw, sqe, iter);
1623 struct io_async_rw *iorw = &req->io->rw;
1626 iov_iter_init(iter, rw, *iovec, iorw->nr_segs, iorw->size);
1627 if (iorw->iov == iorw->fast_iov)
1635 #ifdef CONFIG_COMPAT
1636 if (req->ctx->compat)
1637 return compat_import_iovec(rw, buf, sqe_len, UIO_FASTIOV,
1641 return import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter);
1645 * For files that don't have ->read_iter() and ->write_iter(), handle them
1646 * by looping over ->read() or ->write() manually.
1648 static ssize_t loop_rw_iter(int rw, struct file *file, struct kiocb *kiocb,
1649 struct iov_iter *iter)
1654 * Don't support polled IO through this interface, and we can't
1655 * support non-blocking either. For the latter, this just causes
1656 * the kiocb to be handled from an async context.
1658 if (kiocb->ki_flags & IOCB_HIPRI)
1660 if (kiocb->ki_flags & IOCB_NOWAIT)
1663 while (iov_iter_count(iter)) {
1667 if (!iov_iter_is_bvec(iter)) {
1668 iovec = iov_iter_iovec(iter);
1670 /* fixed buffers import bvec */
1671 iovec.iov_base = kmap(iter->bvec->bv_page)
1673 iovec.iov_len = min(iter->count,
1674 iter->bvec->bv_len - iter->iov_offset);
1678 nr = file->f_op->read(file, iovec.iov_base,
1679 iovec.iov_len, &kiocb->ki_pos);
1681 nr = file->f_op->write(file, iovec.iov_base,
1682 iovec.iov_len, &kiocb->ki_pos);
1685 if (iov_iter_is_bvec(iter))
1686 kunmap(iter->bvec->bv_page);
1694 if (nr != iovec.iov_len)
1696 iov_iter_advance(iter, nr);
1702 static void io_req_map_io(struct io_kiocb *req, ssize_t io_size,
1703 struct iovec *iovec, struct iovec *fast_iov,
1704 struct iov_iter *iter)
1706 req->io->rw.nr_segs = iter->nr_segs;
1707 req->io->rw.size = io_size;
1708 req->io->rw.iov = iovec;
1709 if (!req->io->rw.iov) {
1710 req->io->rw.iov = req->io->rw.fast_iov;
1711 memcpy(req->io->rw.iov, fast_iov,
1712 sizeof(struct iovec) * iter->nr_segs);
1716 static int io_setup_async_io(struct io_kiocb *req, ssize_t io_size,
1717 struct iovec *iovec, struct iovec *fast_iov,
1718 struct iov_iter *iter)
1720 req->io = kmalloc(sizeof(*req->io), GFP_KERNEL);
1722 io_req_map_io(req, io_size, iovec, fast_iov, iter);
1723 memcpy(&req->io->sqe, req->sqe, sizeof(req->io->sqe));
1724 req->sqe = &req->io->sqe;
1731 static int io_read_prep(struct io_kiocb *req, struct iovec **iovec,
1732 struct iov_iter *iter, bool force_nonblock)
1736 ret = io_prep_rw(req, force_nonblock);
1740 if (unlikely(!(req->file->f_mode & FMODE_READ)))
1743 return io_import_iovec(READ, req, iovec, iter);
1746 static int io_read(struct io_kiocb *req, struct io_kiocb **nxt,
1747 bool force_nonblock)
1749 struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
1750 struct kiocb *kiocb = &req->rw;
1751 struct iov_iter iter;
1754 ssize_t io_size, ret;
1757 ret = io_read_prep(req, &iovec, &iter, force_nonblock);
1761 ret = io_import_iovec(READ, req, &iovec, &iter);
1768 if (req->flags & REQ_F_LINK)
1769 req->result = io_size;
1772 * If the file doesn't support async, mark it as REQ_F_MUST_PUNT so
1773 * we know to async punt it even if it was opened O_NONBLOCK
1775 if (force_nonblock && !io_file_supports_async(file)) {
1776 req->flags |= REQ_F_MUST_PUNT;
1780 iov_count = iov_iter_count(&iter);
1781 ret = rw_verify_area(READ, file, &kiocb->ki_pos, iov_count);
1785 if (file->f_op->read_iter)
1786 ret2 = call_read_iter(file, kiocb, &iter);
1788 ret2 = loop_rw_iter(READ, file, kiocb, &iter);
1791 * In case of a short read, punt to async. This can happen
1792 * if we have data partially cached. Alternatively we can
1793 * return the short read, in which case the application will
1794 * need to issue another SQE and wait for it. That SQE will
1795 * need async punt anyway, so it's more efficient to do it
1798 if (force_nonblock && !(req->flags & REQ_F_NOWAIT) &&
1799 (req->flags & REQ_F_ISREG) &&
1800 ret2 > 0 && ret2 < io_size)
1802 /* Catch -EAGAIN return for forced non-blocking submission */
1803 if (!force_nonblock || ret2 != -EAGAIN) {
1804 kiocb_done(kiocb, ret2, nxt, req->in_async);
1807 ret = io_setup_async_io(req, io_size, iovec,
1808 inline_vecs, &iter);
1819 static int io_write_prep(struct io_kiocb *req, struct iovec **iovec,
1820 struct iov_iter *iter, bool force_nonblock)
1824 ret = io_prep_rw(req, force_nonblock);
1828 if (unlikely(!(req->file->f_mode & FMODE_WRITE)))
1831 return io_import_iovec(WRITE, req, iovec, iter);
1834 static int io_write(struct io_kiocb *req, struct io_kiocb **nxt,
1835 bool force_nonblock)
1837 struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
1838 struct kiocb *kiocb = &req->rw;
1839 struct iov_iter iter;
1842 ssize_t ret, io_size;
1845 ret = io_write_prep(req, &iovec, &iter, force_nonblock);
1849 ret = io_import_iovec(WRITE, req, &iovec, &iter);
1854 file = kiocb->ki_filp;
1856 if (req->flags & REQ_F_LINK)
1857 req->result = io_size;
1860 * If the file doesn't support async, mark it as REQ_F_MUST_PUNT so
1861 * we know to async punt it even if it was opened O_NONBLOCK
1863 if (force_nonblock && !io_file_supports_async(req->file)) {
1864 req->flags |= REQ_F_MUST_PUNT;
1868 if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT))
1871 iov_count = iov_iter_count(&iter);
1872 ret = rw_verify_area(WRITE, file, &kiocb->ki_pos, iov_count);
1877 * Open-code file_start_write here to grab freeze protection,
1878 * which will be released by another thread in
1879 * io_complete_rw(). Fool lockdep by telling it the lock got
1880 * released so that it doesn't complain about the held lock when
1881 * we return to userspace.
1883 if (req->flags & REQ_F_ISREG) {
1884 __sb_start_write(file_inode(file)->i_sb,
1885 SB_FREEZE_WRITE, true);
1886 __sb_writers_release(file_inode(file)->i_sb,
1889 kiocb->ki_flags |= IOCB_WRITE;
1891 if (file->f_op->write_iter)
1892 ret2 = call_write_iter(file, kiocb, &iter);
1894 ret2 = loop_rw_iter(WRITE, file, kiocb, &iter);
1895 if (!force_nonblock || ret2 != -EAGAIN) {
1896 kiocb_done(kiocb, ret2, nxt, req->in_async);
1899 ret = io_setup_async_io(req, io_size, iovec,
1900 inline_vecs, &iter);
1912 * IORING_OP_NOP just posts a completion event, nothing else.
1914 static int io_nop(struct io_kiocb *req)
1916 struct io_ring_ctx *ctx = req->ctx;
1918 if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
1921 io_cqring_add_event(req, 0);
1926 static int io_prep_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1928 struct io_ring_ctx *ctx = req->ctx;
1933 if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
1935 if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index))
1941 static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe,
1942 struct io_kiocb **nxt, bool force_nonblock)
1944 loff_t sqe_off = READ_ONCE(sqe->off);
1945 loff_t sqe_len = READ_ONCE(sqe->len);
1946 loff_t end = sqe_off + sqe_len;
1947 unsigned fsync_flags;
1950 fsync_flags = READ_ONCE(sqe->fsync_flags);
1951 if (unlikely(fsync_flags & ~IORING_FSYNC_DATASYNC))
1954 ret = io_prep_fsync(req, sqe);
1958 /* fsync always requires a blocking context */
1962 ret = vfs_fsync_range(req->rw.ki_filp, sqe_off,
1963 end > 0 ? end : LLONG_MAX,
1964 fsync_flags & IORING_FSYNC_DATASYNC);
1967 req_set_fail_links(req);
1968 io_cqring_add_event(req, ret);
1969 io_put_req_find_next(req, nxt);
1973 static int io_prep_sfr(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1975 struct io_ring_ctx *ctx = req->ctx;
1981 if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
1983 if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index))
1989 static int io_sync_file_range(struct io_kiocb *req,
1990 const struct io_uring_sqe *sqe,
1991 struct io_kiocb **nxt,
1992 bool force_nonblock)
1999 ret = io_prep_sfr(req, sqe);
2003 /* sync_file_range always requires a blocking context */
2007 sqe_off = READ_ONCE(sqe->off);
2008 sqe_len = READ_ONCE(sqe->len);
2009 flags = READ_ONCE(sqe->sync_range_flags);
2011 ret = sync_file_range(req->rw.ki_filp, sqe_off, sqe_len, flags);
2014 req_set_fail_links(req);
2015 io_cqring_add_event(req, ret);
2016 io_put_req_find_next(req, nxt);
2020 static int io_sendmsg_prep(struct io_kiocb *req, struct io_async_ctx *io)
2022 #if defined(CONFIG_NET)
2023 const struct io_uring_sqe *sqe = req->sqe;
2024 struct user_msghdr __user *msg;
2027 flags = READ_ONCE(sqe->msg_flags);
2028 msg = (struct user_msghdr __user *)(unsigned long) READ_ONCE(sqe->addr);
2029 io->msg.iov = io->msg.fast_iov;
2030 return sendmsg_copy_msghdr(&io->msg.msg, msg, flags, &io->msg.iov);
2036 static int io_sendmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe,
2037 struct io_kiocb **nxt, bool force_nonblock)
2039 #if defined(CONFIG_NET)
2040 struct socket *sock;
2043 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
2046 sock = sock_from_file(req->file, &ret);
2048 struct io_async_ctx io, *copy;
2049 struct sockaddr_storage addr;
2050 struct msghdr *kmsg;
2053 flags = READ_ONCE(sqe->msg_flags);
2054 if (flags & MSG_DONTWAIT)
2055 req->flags |= REQ_F_NOWAIT;
2056 else if (force_nonblock)
2057 flags |= MSG_DONTWAIT;
2060 kmsg = &req->io->msg.msg;
2061 kmsg->msg_name = &addr;
2064 kmsg->msg_name = &addr;
2065 ret = io_sendmsg_prep(req, &io);
2070 ret = __sys_sendmsg_sock(sock, kmsg, flags);
2071 if (force_nonblock && ret == -EAGAIN) {
2072 copy = kmalloc(sizeof(*copy), GFP_KERNEL);
2077 memcpy(©->msg, &io.msg, sizeof(copy->msg));
2079 memcpy(&req->io->sqe, req->sqe, sizeof(*req->sqe));
2080 req->sqe = &req->io->sqe;
2083 if (ret == -ERESTARTSYS)
2088 io_cqring_add_event(req, ret);
2090 req_set_fail_links(req);
2091 io_put_req_find_next(req, nxt);
2098 static int io_recvmsg_prep(struct io_kiocb *req, struct io_async_ctx *io)
2100 #if defined(CONFIG_NET)
2101 const struct io_uring_sqe *sqe = req->sqe;
2102 struct user_msghdr __user *msg;
2105 flags = READ_ONCE(sqe->msg_flags);
2106 msg = (struct user_msghdr __user *)(unsigned long) READ_ONCE(sqe->addr);
2107 io->msg.iov = io->msg.fast_iov;
2108 return recvmsg_copy_msghdr(&io->msg.msg, msg, flags, &io->msg.uaddr,
2115 static int io_recvmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe,
2116 struct io_kiocb **nxt, bool force_nonblock)
2118 #if defined(CONFIG_NET)
2119 struct socket *sock;
2122 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
2125 sock = sock_from_file(req->file, &ret);
2127 struct user_msghdr __user *msg;
2128 struct io_async_ctx io, *copy;
2129 struct sockaddr_storage addr;
2130 struct msghdr *kmsg;
2133 flags = READ_ONCE(sqe->msg_flags);
2134 if (flags & MSG_DONTWAIT)
2135 req->flags |= REQ_F_NOWAIT;
2136 else if (force_nonblock)
2137 flags |= MSG_DONTWAIT;
2139 msg = (struct user_msghdr __user *) (unsigned long)
2140 READ_ONCE(sqe->addr);
2142 kmsg = &req->io->msg.msg;
2143 kmsg->msg_name = &addr;
2146 kmsg->msg_name = &addr;
2147 ret = io_recvmsg_prep(req, &io);
2152 ret = __sys_recvmsg_sock(sock, kmsg, msg, io.msg.uaddr, flags);
2153 if (force_nonblock && ret == -EAGAIN) {
2154 copy = kmalloc(sizeof(*copy), GFP_KERNEL);
2159 memcpy(copy, &io, sizeof(*copy));
2161 memcpy(&req->io->sqe, req->sqe, sizeof(*req->sqe));
2162 req->sqe = &req->io->sqe;
2165 if (ret == -ERESTARTSYS)
2170 io_cqring_add_event(req, ret);
2172 req_set_fail_links(req);
2173 io_put_req_find_next(req, nxt);
2180 static int io_accept(struct io_kiocb *req, const struct io_uring_sqe *sqe,
2181 struct io_kiocb **nxt, bool force_nonblock)
2183 #if defined(CONFIG_NET)
2184 struct sockaddr __user *addr;
2185 int __user *addr_len;
2186 unsigned file_flags;
2189 if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
2191 if (sqe->ioprio || sqe->len || sqe->buf_index)
2194 addr = (struct sockaddr __user *) (unsigned long) READ_ONCE(sqe->addr);
2195 addr_len = (int __user *) (unsigned long) READ_ONCE(sqe->addr2);
2196 flags = READ_ONCE(sqe->accept_flags);
2197 file_flags = force_nonblock ? O_NONBLOCK : 0;
2199 ret = __sys_accept4_file(req->file, file_flags, addr, addr_len, flags);
2200 if (ret == -EAGAIN && force_nonblock) {
2201 req->work.flags |= IO_WQ_WORK_NEEDS_FILES;
2204 if (ret == -ERESTARTSYS)
2207 req_set_fail_links(req);
2208 io_cqring_add_event(req, ret);
2209 io_put_req_find_next(req, nxt);
2216 static int io_connect_prep(struct io_kiocb *req, struct io_async_ctx *io)
2218 #if defined(CONFIG_NET)
2219 const struct io_uring_sqe *sqe = req->sqe;
2220 struct sockaddr __user *addr;
2223 addr = (struct sockaddr __user *) (unsigned long) READ_ONCE(sqe->addr);
2224 addr_len = READ_ONCE(sqe->addr2);
2225 return move_addr_to_kernel(addr, addr_len, &io->connect.address);
2231 static int io_connect(struct io_kiocb *req, const struct io_uring_sqe *sqe,
2232 struct io_kiocb **nxt, bool force_nonblock)
2234 #if defined(CONFIG_NET)
2235 struct io_async_ctx __io, *io;
2236 unsigned file_flags;
2239 if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
2241 if (sqe->ioprio || sqe->len || sqe->buf_index || sqe->rw_flags)
2244 addr_len = READ_ONCE(sqe->addr2);
2245 file_flags = force_nonblock ? O_NONBLOCK : 0;
2250 ret = io_connect_prep(req, &__io);
2256 ret = __sys_connect_file(req->file, &io->connect.address, addr_len,
2258 if ((ret == -EAGAIN || ret == -EINPROGRESS) && force_nonblock) {
2259 io = kmalloc(sizeof(*io), GFP_KERNEL);
2264 memcpy(&io->connect, &__io.connect, sizeof(io->connect));
2266 memcpy(&io->sqe, req->sqe, sizeof(*req->sqe));
2267 req->sqe = &io->sqe;
2270 if (ret == -ERESTARTSYS)
2274 req_set_fail_links(req);
2275 io_cqring_add_event(req, ret);
2276 io_put_req_find_next(req, nxt);
2283 static void io_poll_remove_one(struct io_kiocb *req)
2285 struct io_poll_iocb *poll = &req->poll;
2287 spin_lock(&poll->head->lock);
2288 WRITE_ONCE(poll->canceled, true);
2289 if (!list_empty(&poll->wait.entry)) {
2290 list_del_init(&poll->wait.entry);
2291 io_queue_async_work(req);
2293 spin_unlock(&poll->head->lock);
2294 hash_del(&req->hash_node);
2297 static void io_poll_remove_all(struct io_ring_ctx *ctx)
2299 struct hlist_node *tmp;
2300 struct io_kiocb *req;
2303 spin_lock_irq(&ctx->completion_lock);
2304 for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
2305 struct hlist_head *list;
2307 list = &ctx->cancel_hash[i];
2308 hlist_for_each_entry_safe(req, tmp, list, hash_node)
2309 io_poll_remove_one(req);
2311 spin_unlock_irq(&ctx->completion_lock);
2314 static int io_poll_cancel(struct io_ring_ctx *ctx, __u64 sqe_addr)
2316 struct hlist_head *list;
2317 struct io_kiocb *req;
2319 list = &ctx->cancel_hash[hash_long(sqe_addr, ctx->cancel_hash_bits)];
2320 hlist_for_each_entry(req, list, hash_node) {
2321 if (sqe_addr == req->user_data) {
2322 io_poll_remove_one(req);
2331 * Find a running poll command that matches one specified in sqe->addr,
2332 * and remove it if found.
2334 static int io_poll_remove(struct io_kiocb *req, const struct io_uring_sqe *sqe)
2336 struct io_ring_ctx *ctx = req->ctx;
2339 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
2341 if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index ||
2345 spin_lock_irq(&ctx->completion_lock);
2346 ret = io_poll_cancel(ctx, READ_ONCE(sqe->addr));
2347 spin_unlock_irq(&ctx->completion_lock);
2349 io_cqring_add_event(req, ret);
2351 req_set_fail_links(req);
2356 static void io_poll_complete(struct io_kiocb *req, __poll_t mask, int error)
2358 struct io_ring_ctx *ctx = req->ctx;
2360 req->poll.done = true;
2362 io_cqring_fill_event(req, error);
2364 io_cqring_fill_event(req, mangle_poll(mask));
2365 io_commit_cqring(ctx);
2368 static void io_poll_complete_work(struct io_wq_work **workptr)
2370 struct io_wq_work *work = *workptr;
2371 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
2372 struct io_poll_iocb *poll = &req->poll;
2373 struct poll_table_struct pt = { ._key = poll->events };
2374 struct io_ring_ctx *ctx = req->ctx;
2375 struct io_kiocb *nxt = NULL;
2379 if (work->flags & IO_WQ_WORK_CANCEL) {
2380 WRITE_ONCE(poll->canceled, true);
2382 } else if (READ_ONCE(poll->canceled)) {
2386 if (ret != -ECANCELED)
2387 mask = vfs_poll(poll->file, &pt) & poll->events;
2390 * Note that ->ki_cancel callers also delete iocb from active_reqs after
2391 * calling ->ki_cancel. We need the ctx_lock roundtrip here to
2392 * synchronize with them. In the cancellation case the list_del_init
2393 * itself is not actually needed, but harmless so we keep it in to
2394 * avoid further branches in the fast path.
2396 spin_lock_irq(&ctx->completion_lock);
2397 if (!mask && ret != -ECANCELED) {
2398 add_wait_queue(poll->head, &poll->wait);
2399 spin_unlock_irq(&ctx->completion_lock);
2402 hash_del(&req->hash_node);
2403 io_poll_complete(req, mask, ret);
2404 spin_unlock_irq(&ctx->completion_lock);
2406 io_cqring_ev_posted(ctx);
2409 req_set_fail_links(req);
2410 io_put_req_find_next(req, &nxt);
2412 *workptr = &nxt->work;
2415 static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
2418 struct io_poll_iocb *poll = wait->private;
2419 struct io_kiocb *req = container_of(poll, struct io_kiocb, poll);
2420 struct io_ring_ctx *ctx = req->ctx;
2421 __poll_t mask = key_to_poll(key);
2422 unsigned long flags;
2424 /* for instances that support it check for an event match first: */
2425 if (mask && !(mask & poll->events))
2428 list_del_init(&poll->wait.entry);
2431 * Run completion inline if we can. We're using trylock here because
2432 * we are violating the completion_lock -> poll wq lock ordering.
2433 * If we have a link timeout we're going to need the completion_lock
2434 * for finalizing the request, mark us as having grabbed that already.
2436 if (mask && spin_trylock_irqsave(&ctx->completion_lock, flags)) {
2437 hash_del(&req->hash_node);
2438 io_poll_complete(req, mask, 0);
2439 req->flags |= REQ_F_COMP_LOCKED;
2441 spin_unlock_irqrestore(&ctx->completion_lock, flags);
2443 io_cqring_ev_posted(ctx);
2445 io_queue_async_work(req);
2451 struct io_poll_table {
2452 struct poll_table_struct pt;
2453 struct io_kiocb *req;
2457 static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head,
2458 struct poll_table_struct *p)
2460 struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
2462 if (unlikely(pt->req->poll.head)) {
2463 pt->error = -EINVAL;
2468 pt->req->poll.head = head;
2469 add_wait_queue(head, &pt->req->poll.wait);
2472 static void io_poll_req_insert(struct io_kiocb *req)
2474 struct io_ring_ctx *ctx = req->ctx;
2475 struct hlist_head *list;
2477 list = &ctx->cancel_hash[hash_long(req->user_data, ctx->cancel_hash_bits)];
2478 hlist_add_head(&req->hash_node, list);
2481 static int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe,
2482 struct io_kiocb **nxt)
2484 struct io_poll_iocb *poll = &req->poll;
2485 struct io_ring_ctx *ctx = req->ctx;
2486 struct io_poll_table ipt;
2487 bool cancel = false;
2491 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
2493 if (sqe->addr || sqe->ioprio || sqe->off || sqe->len || sqe->buf_index)
2499 INIT_IO_WORK(&req->work, io_poll_complete_work);
2500 events = READ_ONCE(sqe->poll_events);
2501 poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP;
2502 INIT_HLIST_NODE(&req->hash_node);
2506 poll->canceled = false;
2508 ipt.pt._qproc = io_poll_queue_proc;
2509 ipt.pt._key = poll->events;
2511 ipt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */
2513 /* initialized the list so that we can do list_empty checks */
2514 INIT_LIST_HEAD(&poll->wait.entry);
2515 init_waitqueue_func_entry(&poll->wait, io_poll_wake);
2516 poll->wait.private = poll;
2518 INIT_LIST_HEAD(&req->list);
2520 mask = vfs_poll(poll->file, &ipt.pt) & poll->events;
2522 spin_lock_irq(&ctx->completion_lock);
2523 if (likely(poll->head)) {
2524 spin_lock(&poll->head->lock);
2525 if (unlikely(list_empty(&poll->wait.entry))) {
2531 if (mask || ipt.error)
2532 list_del_init(&poll->wait.entry);
2534 WRITE_ONCE(poll->canceled, true);
2535 else if (!poll->done) /* actually waiting for an event */
2536 io_poll_req_insert(req);
2537 spin_unlock(&poll->head->lock);
2539 if (mask) { /* no async, we'd stolen it */
2541 io_poll_complete(req, mask, 0);
2543 spin_unlock_irq(&ctx->completion_lock);
2546 io_cqring_ev_posted(ctx);
2547 io_put_req_find_next(req, nxt);
2552 static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
2554 struct io_timeout_data *data = container_of(timer,
2555 struct io_timeout_data, timer);
2556 struct io_kiocb *req = data->req;
2557 struct io_ring_ctx *ctx = req->ctx;
2558 unsigned long flags;
2560 atomic_inc(&ctx->cq_timeouts);
2562 spin_lock_irqsave(&ctx->completion_lock, flags);
2564 * We could be racing with timeout deletion. If the list is empty,
2565 * then timeout lookup already found it and will be handling it.
2567 if (!list_empty(&req->list)) {
2568 struct io_kiocb *prev;
2571 * Adjust the reqs sequence before the current one because it
2572 * will consume a slot in the cq_ring and the the cq_tail
2573 * pointer will be increased, otherwise other timeout reqs may
2574 * return in advance without waiting for enough wait_nr.
2577 list_for_each_entry_continue_reverse(prev, &ctx->timeout_list, list)
2579 list_del_init(&req->list);
2582 io_cqring_fill_event(req, -ETIME);
2583 io_commit_cqring(ctx);
2584 spin_unlock_irqrestore(&ctx->completion_lock, flags);
2586 io_cqring_ev_posted(ctx);
2587 req_set_fail_links(req);
2589 return HRTIMER_NORESTART;
2592 static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data)
2594 struct io_kiocb *req;
2597 list_for_each_entry(req, &ctx->timeout_list, list) {
2598 if (user_data == req->user_data) {
2599 list_del_init(&req->list);
2608 ret = hrtimer_try_to_cancel(&req->io->timeout.timer);
2612 req_set_fail_links(req);
2613 io_cqring_fill_event(req, -ECANCELED);
2619 * Remove or update an existing timeout command
2621 static int io_timeout_remove(struct io_kiocb *req,
2622 const struct io_uring_sqe *sqe)
2624 struct io_ring_ctx *ctx = req->ctx;
2628 if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
2630 if (sqe->flags || sqe->ioprio || sqe->buf_index || sqe->len)
2632 flags = READ_ONCE(sqe->timeout_flags);
2636 spin_lock_irq(&ctx->completion_lock);
2637 ret = io_timeout_cancel(ctx, READ_ONCE(sqe->addr));
2639 io_cqring_fill_event(req, ret);
2640 io_commit_cqring(ctx);
2641 spin_unlock_irq(&ctx->completion_lock);
2642 io_cqring_ev_posted(ctx);
2644 req_set_fail_links(req);
2649 static int io_timeout_prep(struct io_kiocb *req, struct io_async_ctx *io,
2650 bool is_timeout_link)
2652 const struct io_uring_sqe *sqe = req->sqe;
2653 struct io_timeout_data *data;
2656 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
2658 if (sqe->ioprio || sqe->buf_index || sqe->len != 1)
2660 if (sqe->off && is_timeout_link)
2662 flags = READ_ONCE(sqe->timeout_flags);
2663 if (flags & ~IORING_TIMEOUT_ABS)
2666 data = &io->timeout;
2668 req->flags |= REQ_F_TIMEOUT;
2670 if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr)))
2673 if (flags & IORING_TIMEOUT_ABS)
2674 data->mode = HRTIMER_MODE_ABS;
2676 data->mode = HRTIMER_MODE_REL;
2678 hrtimer_init(&data->timer, CLOCK_MONOTONIC, data->mode);
2683 static int io_timeout(struct io_kiocb *req, const struct io_uring_sqe *sqe)
2686 struct io_ring_ctx *ctx = req->ctx;
2687 struct io_timeout_data *data;
2688 struct io_async_ctx *io;
2689 struct list_head *entry;
2696 io = kmalloc(sizeof(*io), GFP_KERNEL);
2699 ret = io_timeout_prep(req, io, false);
2705 data = &req->io->timeout;
2708 * sqe->off holds how many events that need to occur for this
2709 * timeout event to be satisfied. If it isn't set, then this is
2710 * a pure timeout request, sequence isn't used.
2712 count = READ_ONCE(sqe->off);
2714 req->flags |= REQ_F_TIMEOUT_NOSEQ;
2715 spin_lock_irq(&ctx->completion_lock);
2716 entry = ctx->timeout_list.prev;
2720 req->sequence = ctx->cached_sq_head + count - 1;
2721 data->seq_offset = count;
2724 * Insertion sort, ensuring the first entry in the list is always
2725 * the one we need first.
2727 spin_lock_irq(&ctx->completion_lock);
2728 list_for_each_prev(entry, &ctx->timeout_list) {
2729 struct io_kiocb *nxt = list_entry(entry, struct io_kiocb, list);
2730 unsigned nxt_sq_head;
2731 long long tmp, tmp_nxt;
2732 u32 nxt_offset = nxt->io->timeout.seq_offset;
2734 if (nxt->flags & REQ_F_TIMEOUT_NOSEQ)
2738 * Since cached_sq_head + count - 1 can overflow, use type long
2741 tmp = (long long)ctx->cached_sq_head + count - 1;
2742 nxt_sq_head = nxt->sequence - nxt_offset + 1;
2743 tmp_nxt = (long long)nxt_sq_head + nxt_offset - 1;
2746 * cached_sq_head may overflow, and it will never overflow twice
2747 * once there is some timeout req still be valid.
2749 if (ctx->cached_sq_head < nxt_sq_head)
2756 * Sequence of reqs after the insert one and itself should
2757 * be adjusted because each timeout req consumes a slot.
2762 req->sequence -= span;
2764 list_add(&req->list, entry);
2765 data->timer.function = io_timeout_fn;
2766 hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode);
2767 spin_unlock_irq(&ctx->completion_lock);
2771 static bool io_cancel_cb(struct io_wq_work *work, void *data)
2773 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
2775 return req->user_data == (unsigned long) data;
2778 static int io_async_cancel_one(struct io_ring_ctx *ctx, void *sqe_addr)
2780 enum io_wq_cancel cancel_ret;
2783 cancel_ret = io_wq_cancel_cb(ctx->io_wq, io_cancel_cb, sqe_addr);
2784 switch (cancel_ret) {
2785 case IO_WQ_CANCEL_OK:
2788 case IO_WQ_CANCEL_RUNNING:
2791 case IO_WQ_CANCEL_NOTFOUND:
2799 static void io_async_find_and_cancel(struct io_ring_ctx *ctx,
2800 struct io_kiocb *req, __u64 sqe_addr,
2801 struct io_kiocb **nxt, int success_ret)
2803 unsigned long flags;
2806 ret = io_async_cancel_one(ctx, (void *) (unsigned long) sqe_addr);
2807 if (ret != -ENOENT) {
2808 spin_lock_irqsave(&ctx->completion_lock, flags);
2812 spin_lock_irqsave(&ctx->completion_lock, flags);
2813 ret = io_timeout_cancel(ctx, sqe_addr);
2816 ret = io_poll_cancel(ctx, sqe_addr);
2820 io_cqring_fill_event(req, ret);
2821 io_commit_cqring(ctx);
2822 spin_unlock_irqrestore(&ctx->completion_lock, flags);
2823 io_cqring_ev_posted(ctx);
2826 req_set_fail_links(req);
2827 io_put_req_find_next(req, nxt);
2830 static int io_async_cancel(struct io_kiocb *req, const struct io_uring_sqe *sqe,
2831 struct io_kiocb **nxt)
2833 struct io_ring_ctx *ctx = req->ctx;
2835 if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
2837 if (sqe->flags || sqe->ioprio || sqe->off || sqe->len ||
2841 io_async_find_and_cancel(ctx, req, READ_ONCE(sqe->addr), nxt, 0);
2845 static int io_req_defer_prep(struct io_kiocb *req, struct io_async_ctx *io)
2847 struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
2848 struct iov_iter iter;
2851 memcpy(&io->sqe, req->sqe, sizeof(io->sqe));
2852 req->sqe = &io->sqe;
2854 switch (io->sqe.opcode) {
2855 case IORING_OP_READV:
2856 case IORING_OP_READ_FIXED:
2857 ret = io_read_prep(req, &iovec, &iter, true);
2859 case IORING_OP_WRITEV:
2860 case IORING_OP_WRITE_FIXED:
2861 ret = io_write_prep(req, &iovec, &iter, true);
2863 case IORING_OP_SENDMSG:
2864 ret = io_sendmsg_prep(req, io);
2866 case IORING_OP_RECVMSG:
2867 ret = io_recvmsg_prep(req, io);
2869 case IORING_OP_CONNECT:
2870 ret = io_connect_prep(req, io);
2872 case IORING_OP_TIMEOUT:
2873 return io_timeout_prep(req, io, false);
2874 case IORING_OP_LINK_TIMEOUT:
2875 return io_timeout_prep(req, io, true);
2885 io_req_map_io(req, ret, iovec, inline_vecs, &iter);
2889 static int io_req_defer(struct io_kiocb *req)
2891 struct io_ring_ctx *ctx = req->ctx;
2892 struct io_async_ctx *io;
2895 /* Still need defer if there is pending req in defer list. */
2896 if (!req_need_defer(req) && list_empty(&ctx->defer_list))
2899 io = kmalloc(sizeof(*io), GFP_KERNEL);
2903 ret = io_req_defer_prep(req, io);
2909 spin_lock_irq(&ctx->completion_lock);
2910 if (!req_need_defer(req) && list_empty(&ctx->defer_list)) {
2911 spin_unlock_irq(&ctx->completion_lock);
2915 trace_io_uring_defer(ctx, req, req->user_data);
2916 list_add_tail(&req->list, &ctx->defer_list);
2917 spin_unlock_irq(&ctx->completion_lock);
2918 return -EIOCBQUEUED;
2921 __attribute__((nonnull))
2922 static int io_issue_sqe(struct io_kiocb *req, struct io_kiocb **nxt,
2923 bool force_nonblock)
2926 struct io_ring_ctx *ctx = req->ctx;
2928 opcode = READ_ONCE(req->sqe->opcode);
2933 case IORING_OP_READV:
2934 if (unlikely(req->sqe->buf_index))
2936 ret = io_read(req, nxt, force_nonblock);
2938 case IORING_OP_WRITEV:
2939 if (unlikely(req->sqe->buf_index))
2941 ret = io_write(req, nxt, force_nonblock);
2943 case IORING_OP_READ_FIXED:
2944 ret = io_read(req, nxt, force_nonblock);
2946 case IORING_OP_WRITE_FIXED:
2947 ret = io_write(req, nxt, force_nonblock);
2949 case IORING_OP_FSYNC:
2950 ret = io_fsync(req, req->sqe, nxt, force_nonblock);
2952 case IORING_OP_POLL_ADD:
2953 ret = io_poll_add(req, req->sqe, nxt);
2955 case IORING_OP_POLL_REMOVE:
2956 ret = io_poll_remove(req, req->sqe);
2958 case IORING_OP_SYNC_FILE_RANGE:
2959 ret = io_sync_file_range(req, req->sqe, nxt, force_nonblock);
2961 case IORING_OP_SENDMSG:
2962 ret = io_sendmsg(req, req->sqe, nxt, force_nonblock);
2964 case IORING_OP_RECVMSG:
2965 ret = io_recvmsg(req, req->sqe, nxt, force_nonblock);
2967 case IORING_OP_TIMEOUT:
2968 ret = io_timeout(req, req->sqe);
2970 case IORING_OP_TIMEOUT_REMOVE:
2971 ret = io_timeout_remove(req, req->sqe);
2973 case IORING_OP_ACCEPT:
2974 ret = io_accept(req, req->sqe, nxt, force_nonblock);
2976 case IORING_OP_CONNECT:
2977 ret = io_connect(req, req->sqe, nxt, force_nonblock);
2979 case IORING_OP_ASYNC_CANCEL:
2980 ret = io_async_cancel(req, req->sqe, nxt);
2990 if (ctx->flags & IORING_SETUP_IOPOLL) {
2991 if (req->result == -EAGAIN)
2994 io_iopoll_req_issued(req);
3000 static void io_link_work_cb(struct io_wq_work **workptr)
3002 struct io_wq_work *work = *workptr;
3003 struct io_kiocb *link = work->data;
3005 io_queue_linked_timeout(link);
3006 work->func = io_wq_submit_work;
3009 static void io_wq_submit_work(struct io_wq_work **workptr)
3011 struct io_wq_work *work = *workptr;
3012 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
3013 struct io_kiocb *nxt = NULL;
3016 /* Ensure we clear previously set non-block flag */
3017 req->rw.ki_flags &= ~IOCB_NOWAIT;
3019 if (work->flags & IO_WQ_WORK_CANCEL)
3023 req->has_user = (work->flags & IO_WQ_WORK_HAS_MM) != 0;
3024 req->in_async = true;
3026 ret = io_issue_sqe(req, &nxt, false);
3028 * We can get EAGAIN for polled IO even though we're
3029 * forcing a sync submission from here, since we can't
3030 * wait for request slots on the block side.
3038 /* drop submission reference */
3042 req_set_fail_links(req);
3043 io_cqring_add_event(req, ret);
3047 /* if a dependent link is ready, pass it back */
3049 struct io_kiocb *link;
3051 io_prep_async_work(nxt, &link);
3052 *workptr = &nxt->work;
3054 nxt->work.flags |= IO_WQ_WORK_CB;
3055 nxt->work.func = io_link_work_cb;
3056 nxt->work.data = link;
3061 static bool io_op_needs_file(const struct io_uring_sqe *sqe)
3063 int op = READ_ONCE(sqe->opcode);
3067 case IORING_OP_POLL_REMOVE:
3068 case IORING_OP_TIMEOUT:
3069 case IORING_OP_TIMEOUT_REMOVE:
3070 case IORING_OP_ASYNC_CANCEL:
3071 case IORING_OP_LINK_TIMEOUT:
3078 static inline struct file *io_file_from_index(struct io_ring_ctx *ctx,
3081 struct fixed_file_table *table;
3083 table = &ctx->file_table[index >> IORING_FILE_TABLE_SHIFT];
3084 return table->files[index & IORING_FILE_TABLE_MASK];
3087 static int io_req_set_file(struct io_submit_state *state, struct io_kiocb *req)
3089 struct io_ring_ctx *ctx = req->ctx;
3093 flags = READ_ONCE(req->sqe->flags);
3094 fd = READ_ONCE(req->sqe->fd);
3096 if (flags & IOSQE_IO_DRAIN)
3097 req->flags |= REQ_F_IO_DRAIN;
3099 if (!io_op_needs_file(req->sqe))
3102 if (flags & IOSQE_FIXED_FILE) {
3103 if (unlikely(!ctx->file_table ||
3104 (unsigned) fd >= ctx->nr_user_files))
3106 fd = array_index_nospec(fd, ctx->nr_user_files);
3107 req->file = io_file_from_index(ctx, fd);
3110 req->flags |= REQ_F_FIXED_FILE;
3112 if (req->needs_fixed_file)
3114 trace_io_uring_file_get(ctx, fd);
3115 req->file = io_file_get(state, fd);
3116 if (unlikely(!req->file))
3123 static int io_grab_files(struct io_kiocb *req)
3126 struct io_ring_ctx *ctx = req->ctx;
3129 spin_lock_irq(&ctx->inflight_lock);
3131 * We use the f_ops->flush() handler to ensure that we can flush
3132 * out work accessing these files if the fd is closed. Check if
3133 * the fd has changed since we started down this path, and disallow
3134 * this operation if it has.
3136 if (fcheck(req->ring_fd) == req->ring_file) {
3137 list_add(&req->inflight_entry, &ctx->inflight_list);
3138 req->flags |= REQ_F_INFLIGHT;
3139 req->work.files = current->files;
3142 spin_unlock_irq(&ctx->inflight_lock);
3148 static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer)
3150 struct io_timeout_data *data = container_of(timer,
3151 struct io_timeout_data, timer);
3152 struct io_kiocb *req = data->req;
3153 struct io_ring_ctx *ctx = req->ctx;
3154 struct io_kiocb *prev = NULL;
3155 unsigned long flags;
3157 spin_lock_irqsave(&ctx->completion_lock, flags);
3160 * We don't expect the list to be empty, that will only happen if we
3161 * race with the completion of the linked work.
3163 if (!list_empty(&req->link_list)) {
3164 prev = list_entry(req->link_list.prev, struct io_kiocb,
3166 if (refcount_inc_not_zero(&prev->refs)) {
3167 list_del_init(&req->link_list);
3168 prev->flags &= ~REQ_F_LINK_TIMEOUT;
3173 spin_unlock_irqrestore(&ctx->completion_lock, flags);
3176 req_set_fail_links(prev);
3177 io_async_find_and_cancel(ctx, req, prev->user_data, NULL,
3181 io_cqring_add_event(req, -ETIME);
3184 return HRTIMER_NORESTART;
3187 static void io_queue_linked_timeout(struct io_kiocb *req)
3189 struct io_ring_ctx *ctx = req->ctx;
3192 * If the list is now empty, then our linked request finished before
3193 * we got a chance to setup the timer
3195 spin_lock_irq(&ctx->completion_lock);
3196 if (!list_empty(&req->link_list)) {
3197 struct io_timeout_data *data = &req->io->timeout;
3199 data->timer.function = io_link_timeout_fn;
3200 hrtimer_start(&data->timer, timespec64_to_ktime(data->ts),
3203 spin_unlock_irq(&ctx->completion_lock);
3205 /* drop submission reference */
3209 static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
3211 struct io_kiocb *nxt;
3213 if (!(req->flags & REQ_F_LINK))
3216 nxt = list_first_entry_or_null(&req->link_list, struct io_kiocb,
3218 if (!nxt || nxt->sqe->opcode != IORING_OP_LINK_TIMEOUT)
3221 req->flags |= REQ_F_LINK_TIMEOUT;
3225 static void __io_queue_sqe(struct io_kiocb *req)
3227 struct io_kiocb *linked_timeout;
3228 struct io_kiocb *nxt = NULL;
3232 linked_timeout = io_prep_linked_timeout(req);
3234 ret = io_issue_sqe(req, &nxt, true);
3237 * We async punt it if the file wasn't marked NOWAIT, or if the file
3238 * doesn't support non-blocking read/write attempts
3240 if (ret == -EAGAIN && (!(req->flags & REQ_F_NOWAIT) ||
3241 (req->flags & REQ_F_MUST_PUNT))) {
3242 if (req->work.flags & IO_WQ_WORK_NEEDS_FILES) {
3243 ret = io_grab_files(req);
3249 * Queued up for async execution, worker will release
3250 * submit reference when the iocb is actually submitted.
3252 io_queue_async_work(req);
3257 /* drop submission reference */
3260 if (linked_timeout) {
3262 io_queue_linked_timeout(linked_timeout);
3264 io_put_req(linked_timeout);
3267 /* and drop final reference, if we failed */
3269 io_cqring_add_event(req, ret);
3270 req_set_fail_links(req);
3281 static void io_queue_sqe(struct io_kiocb *req)
3285 if (unlikely(req->ctx->drain_next)) {
3286 req->flags |= REQ_F_IO_DRAIN;
3287 req->ctx->drain_next = false;
3289 req->ctx->drain_next = (req->flags & REQ_F_DRAIN_LINK);
3291 ret = io_req_defer(req);
3293 if (ret != -EIOCBQUEUED) {
3294 io_cqring_add_event(req, ret);
3295 req_set_fail_links(req);
3296 io_double_put_req(req);
3299 __io_queue_sqe(req);
3302 static inline void io_queue_link_head(struct io_kiocb *req)
3304 if (unlikely(req->flags & REQ_F_FAIL_LINK)) {
3305 io_cqring_add_event(req, -ECANCELED);
3306 io_double_put_req(req);
3312 #define SQE_VALID_FLAGS (IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK| \
3315 static bool io_submit_sqe(struct io_kiocb *req, struct io_submit_state *state,
3316 struct io_kiocb **link)
3318 struct io_ring_ctx *ctx = req->ctx;
3321 req->user_data = req->sqe->user_data;
3323 /* enforce forwards compatibility on users */
3324 if (unlikely(req->sqe->flags & ~SQE_VALID_FLAGS)) {
3329 ret = io_req_set_file(state, req);
3330 if (unlikely(ret)) {
3332 io_cqring_add_event(req, ret);
3333 io_double_put_req(req);
3338 * If we already have a head request, queue this one for async
3339 * submittal once the head completes. If we don't have a head but
3340 * IOSQE_IO_LINK is set in the sqe, start a new head. This one will be
3341 * submitted sync once the chain is complete. If none of those
3342 * conditions are true (normal request), then just queue it.
3345 struct io_kiocb *prev = *link;
3346 struct io_async_ctx *io;
3348 if (req->sqe->flags & IOSQE_IO_DRAIN)
3349 (*link)->flags |= REQ_F_DRAIN_LINK | REQ_F_IO_DRAIN;
3351 if (req->sqe->flags & IOSQE_IO_HARDLINK)
3352 req->flags |= REQ_F_HARDLINK;
3354 io = kmalloc(sizeof(*io), GFP_KERNEL);
3360 ret = io_req_defer_prep(req, io);
3363 /* fail even hard links since we don't submit */
3364 prev->flags |= REQ_F_FAIL_LINK;
3367 trace_io_uring_link(ctx, req, prev);
3368 list_add_tail(&req->link_list, &prev->link_list);
3369 } else if (req->sqe->flags & (IOSQE_IO_LINK|IOSQE_IO_HARDLINK)) {
3370 req->flags |= REQ_F_LINK;
3371 if (req->sqe->flags & IOSQE_IO_HARDLINK)
3372 req->flags |= REQ_F_HARDLINK;
3374 INIT_LIST_HEAD(&req->link_list);
3384 * Batched submission is done, ensure local IO is flushed out.
3386 static void io_submit_state_end(struct io_submit_state *state)
3388 blk_finish_plug(&state->plug);
3390 if (state->free_reqs)
3391 kmem_cache_free_bulk(req_cachep, state->free_reqs,
3392 &state->reqs[state->cur_req]);
3396 * Start submission side cache.
3398 static void io_submit_state_start(struct io_submit_state *state,
3399 unsigned int max_ios)
3401 blk_start_plug(&state->plug);
3402 state->free_reqs = 0;
3404 state->ios_left = max_ios;
3407 static void io_commit_sqring(struct io_ring_ctx *ctx)
3409 struct io_rings *rings = ctx->rings;
3411 if (ctx->cached_sq_head != READ_ONCE(rings->sq.head)) {
3413 * Ensure any loads from the SQEs are done at this point,
3414 * since once we write the new head, the application could
3415 * write new data to them.
3417 smp_store_release(&rings->sq.head, ctx->cached_sq_head);
3422 * Fetch an sqe, if one is available. Note that s->sqe will point to memory
3423 * that is mapped by userspace. This means that care needs to be taken to
3424 * ensure that reads are stable, as we cannot rely on userspace always
3425 * being a good citizen. If members of the sqe are validated and then later
3426 * used, it's important that those reads are done through READ_ONCE() to
3427 * prevent a re-load down the line.
3429 static bool io_get_sqring(struct io_ring_ctx *ctx, struct io_kiocb *req)
3431 struct io_rings *rings = ctx->rings;
3432 u32 *sq_array = ctx->sq_array;
3436 * The cached sq head (or cq tail) serves two purposes:
3438 * 1) allows us to batch the cost of updating the user visible
3440 * 2) allows the kernel side to track the head on its own, even
3441 * though the application is the one updating it.
3443 head = ctx->cached_sq_head;
3444 /* make sure SQ entry isn't read before tail */
3445 if (unlikely(head == smp_load_acquire(&rings->sq.tail)))
3448 head = READ_ONCE(sq_array[head & ctx->sq_mask]);
3449 if (likely(head < ctx->sq_entries)) {
3451 * All io need record the previous position, if LINK vs DARIN,
3452 * it can be used to mark the position of the first IO in the
3455 req->sequence = ctx->cached_sq_head;
3456 req->sqe = &ctx->sq_sqes[head];
3457 ctx->cached_sq_head++;
3461 /* drop invalid entries */
3462 ctx->cached_sq_head++;
3463 ctx->cached_sq_dropped++;
3464 WRITE_ONCE(rings->sq_dropped, ctx->cached_sq_dropped);
3468 static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
3469 struct file *ring_file, int ring_fd,
3470 struct mm_struct **mm, bool async)
3472 struct io_submit_state state, *statep = NULL;
3473 struct io_kiocb *link = NULL;
3474 int i, submitted = 0;
3475 bool mm_fault = false;
3477 /* if we have a backlog and couldn't flush it all, return BUSY */
3478 if (!list_empty(&ctx->cq_overflow_list) &&
3479 !io_cqring_overflow_flush(ctx, false))
3482 if (nr > IO_PLUG_THRESHOLD) {
3483 io_submit_state_start(&state, nr);
3487 for (i = 0; i < nr; i++) {
3488 struct io_kiocb *req;
3489 unsigned int sqe_flags;
3491 req = io_get_req(ctx, statep);
3492 if (unlikely(!req)) {
3494 submitted = -EAGAIN;
3497 if (!io_get_sqring(ctx, req)) {
3502 if (io_sqe_needs_user(req->sqe) && !*mm) {
3503 mm_fault = mm_fault || !mmget_not_zero(ctx->sqo_mm);
3505 use_mm(ctx->sqo_mm);
3511 sqe_flags = req->sqe->flags;
3513 req->ring_file = ring_file;
3514 req->ring_fd = ring_fd;
3515 req->has_user = *mm != NULL;
3516 req->in_async = async;
3517 req->needs_fixed_file = async;
3518 trace_io_uring_submit_sqe(ctx, req->sqe->user_data,
3520 if (!io_submit_sqe(req, statep, &link))
3523 * If previous wasn't linked and we have a linked command,
3524 * that's the end of the chain. Submit the previous link.
3526 if (!(sqe_flags & IOSQE_IO_LINK) && link) {
3527 io_queue_link_head(link);
3533 io_queue_link_head(link);
3535 io_submit_state_end(&state);
3537 /* Commit SQ ring head once we've consumed and submitted all SQEs */
3538 io_commit_sqring(ctx);
3543 static int io_sq_thread(void *data)
3545 struct io_ring_ctx *ctx = data;
3546 struct mm_struct *cur_mm = NULL;
3547 const struct cred *old_cred;
3548 mm_segment_t old_fs;
3551 unsigned long timeout;
3554 complete(&ctx->completions[1]);
3558 old_cred = override_creds(ctx->creds);
3560 ret = timeout = inflight = 0;
3561 while (!kthread_should_park()) {
3562 unsigned int to_submit;
3565 unsigned nr_events = 0;
3567 if (ctx->flags & IORING_SETUP_IOPOLL) {
3569 * inflight is the count of the maximum possible
3570 * entries we submitted, but it can be smaller
3571 * if we dropped some of them. If we don't have
3572 * poll entries available, then we know that we
3573 * have nothing left to poll for. Reset the
3574 * inflight count to zero in that case.
3576 mutex_lock(&ctx->uring_lock);
3577 if (!list_empty(&ctx->poll_list))
3578 __io_iopoll_check(ctx, &nr_events, 0);
3581 mutex_unlock(&ctx->uring_lock);
3584 * Normal IO, just pretend everything completed.
3585 * We don't have to poll completions for that.
3587 nr_events = inflight;
3590 inflight -= nr_events;
3592 timeout = jiffies + ctx->sq_thread_idle;
3595 to_submit = io_sqring_entries(ctx);
3598 * If submit got -EBUSY, flag us as needing the application
3599 * to enter the kernel to reap and flush events.
3601 if (!to_submit || ret == -EBUSY) {
3603 * We're polling. If we're within the defined idle
3604 * period, then let us spin without work before going
3605 * to sleep. The exception is if we got EBUSY doing
3606 * more IO, we should wait for the application to
3607 * reap events and wake us up.
3610 (!time_after(jiffies, timeout) && ret != -EBUSY)) {
3616 * Drop cur_mm before scheduling, we can't hold it for
3617 * long periods (or over schedule()). Do this before
3618 * adding ourselves to the waitqueue, as the unuse/drop
3627 prepare_to_wait(&ctx->sqo_wait, &wait,
3628 TASK_INTERRUPTIBLE);
3630 /* Tell userspace we may need a wakeup call */
3631 ctx->rings->sq_flags |= IORING_SQ_NEED_WAKEUP;
3632 /* make sure to read SQ tail after writing flags */
3635 to_submit = io_sqring_entries(ctx);
3636 if (!to_submit || ret == -EBUSY) {
3637 if (kthread_should_park()) {
3638 finish_wait(&ctx->sqo_wait, &wait);
3641 if (signal_pending(current))
3642 flush_signals(current);
3644 finish_wait(&ctx->sqo_wait, &wait);
3646 ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
3649 finish_wait(&ctx->sqo_wait, &wait);
3651 ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
3654 to_submit = min(to_submit, ctx->sq_entries);
3655 mutex_lock(&ctx->uring_lock);
3656 ret = io_submit_sqes(ctx, to_submit, NULL, -1, &cur_mm, true);
3657 mutex_unlock(&ctx->uring_lock);
3667 revert_creds(old_cred);
3674 struct io_wait_queue {
3675 struct wait_queue_entry wq;
3676 struct io_ring_ctx *ctx;
3678 unsigned nr_timeouts;
3681 static inline bool io_should_wake(struct io_wait_queue *iowq, bool noflush)
3683 struct io_ring_ctx *ctx = iowq->ctx;
3686 * Wake up if we have enough events, or if a timeout occured since we
3687 * started waiting. For timeouts, we always want to return to userspace,
3688 * regardless of event count.
3690 return io_cqring_events(ctx, noflush) >= iowq->to_wait ||
3691 atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
3694 static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode,
3695 int wake_flags, void *key)
3697 struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue,
3700 /* use noflush == true, as we can't safely rely on locking context */
3701 if (!io_should_wake(iowq, true))
3704 return autoremove_wake_function(curr, mode, wake_flags, key);
3708 * Wait until events become available, if we don't already have some. The
3709 * application must reap them itself, as they reside on the shared cq ring.
3711 static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
3712 const sigset_t __user *sig, size_t sigsz)
3714 struct io_wait_queue iowq = {
3717 .func = io_wake_function,
3718 .entry = LIST_HEAD_INIT(iowq.wq.entry),
3721 .to_wait = min_events,
3723 struct io_rings *rings = ctx->rings;
3726 if (io_cqring_events(ctx, false) >= min_events)
3730 #ifdef CONFIG_COMPAT
3731 if (in_compat_syscall())
3732 ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig,
3736 ret = set_user_sigmask(sig, sigsz);
3742 iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts);
3743 trace_io_uring_cqring_wait(ctx, min_events);
3745 prepare_to_wait_exclusive(&ctx->wait, &iowq.wq,
3746 TASK_INTERRUPTIBLE);
3747 if (io_should_wake(&iowq, false))
3750 if (signal_pending(current)) {
3755 finish_wait(&ctx->wait, &iowq.wq);
3757 restore_saved_sigmask_unless(ret == -EINTR);
3759 return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0;
3762 static void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
3764 #if defined(CONFIG_UNIX)
3765 if (ctx->ring_sock) {
3766 struct sock *sock = ctx->ring_sock->sk;
3767 struct sk_buff *skb;
3769 while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL)
3775 for (i = 0; i < ctx->nr_user_files; i++) {
3778 file = io_file_from_index(ctx, i);
3785 static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
3787 unsigned nr_tables, i;
3789 if (!ctx->file_table)
3792 __io_sqe_files_unregister(ctx);
3793 nr_tables = DIV_ROUND_UP(ctx->nr_user_files, IORING_MAX_FILES_TABLE);
3794 for (i = 0; i < nr_tables; i++)
3795 kfree(ctx->file_table[i].files);
3796 kfree(ctx->file_table);
3797 ctx->file_table = NULL;
3798 ctx->nr_user_files = 0;
3802 static void io_sq_thread_stop(struct io_ring_ctx *ctx)
3804 if (ctx->sqo_thread) {
3805 wait_for_completion(&ctx->completions[1]);
3807 * The park is a bit of a work-around, without it we get
3808 * warning spews on shutdown with SQPOLL set and affinity
3809 * set to a single CPU.
3811 kthread_park(ctx->sqo_thread);
3812 kthread_stop(ctx->sqo_thread);
3813 ctx->sqo_thread = NULL;
3817 static void io_finish_async(struct io_ring_ctx *ctx)
3819 io_sq_thread_stop(ctx);
3822 io_wq_destroy(ctx->io_wq);
3827 #if defined(CONFIG_UNIX)
3828 static void io_destruct_skb(struct sk_buff *skb)
3830 struct io_ring_ctx *ctx = skb->sk->sk_user_data;
3833 io_wq_flush(ctx->io_wq);
3835 unix_destruct_scm(skb);
3839 * Ensure the UNIX gc is aware of our file set, so we are certain that
3840 * the io_uring can be safely unregistered on process exit, even if we have
3841 * loops in the file referencing.
3843 static int __io_sqe_files_scm(struct io_ring_ctx *ctx, int nr, int offset)
3845 struct sock *sk = ctx->ring_sock->sk;
3846 struct scm_fp_list *fpl;
3847 struct sk_buff *skb;
3850 if (!capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) {
3851 unsigned long inflight = ctx->user->unix_inflight + nr;
3853 if (inflight > task_rlimit(current, RLIMIT_NOFILE))
3857 fpl = kzalloc(sizeof(*fpl), GFP_KERNEL);
3861 skb = alloc_skb(0, GFP_KERNEL);
3870 fpl->user = get_uid(ctx->user);
3871 for (i = 0; i < nr; i++) {
3872 struct file *file = io_file_from_index(ctx, i + offset);
3876 fpl->fp[nr_files] = get_file(file);
3877 unix_inflight(fpl->user, fpl->fp[nr_files]);
3882 fpl->max = SCM_MAX_FD;
3883 fpl->count = nr_files;
3884 UNIXCB(skb).fp = fpl;
3885 skb->destructor = io_destruct_skb;
3886 refcount_add(skb->truesize, &sk->sk_wmem_alloc);
3887 skb_queue_head(&sk->sk_receive_queue, skb);
3889 for (i = 0; i < nr_files; i++)
3900 * If UNIX sockets are enabled, fd passing can cause a reference cycle which
3901 * causes regular reference counting to break down. We rely on the UNIX
3902 * garbage collection to take care of this problem for us.
3904 static int io_sqe_files_scm(struct io_ring_ctx *ctx)
3906 unsigned left, total;
3910 left = ctx->nr_user_files;
3912 unsigned this_files = min_t(unsigned, left, SCM_MAX_FD);
3914 ret = __io_sqe_files_scm(ctx, this_files, total);
3918 total += this_files;
3924 while (total < ctx->nr_user_files) {
3925 struct file *file = io_file_from_index(ctx, total);
3935 static int io_sqe_files_scm(struct io_ring_ctx *ctx)
3941 static int io_sqe_alloc_file_tables(struct io_ring_ctx *ctx, unsigned nr_tables,
3946 for (i = 0; i < nr_tables; i++) {
3947 struct fixed_file_table *table = &ctx->file_table[i];
3948 unsigned this_files;
3950 this_files = min(nr_files, IORING_MAX_FILES_TABLE);
3951 table->files = kcalloc(this_files, sizeof(struct file *),
3955 nr_files -= this_files;
3961 for (i = 0; i < nr_tables; i++) {
3962 struct fixed_file_table *table = &ctx->file_table[i];
3963 kfree(table->files);
3968 static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
3971 __s32 __user *fds = (__s32 __user *) arg;
3976 if (ctx->file_table)
3980 if (nr_args > IORING_MAX_FIXED_FILES)
3983 nr_tables = DIV_ROUND_UP(nr_args, IORING_MAX_FILES_TABLE);
3984 ctx->file_table = kcalloc(nr_tables, sizeof(struct fixed_file_table),
3986 if (!ctx->file_table)
3989 if (io_sqe_alloc_file_tables(ctx, nr_tables, nr_args)) {
3990 kfree(ctx->file_table);
3991 ctx->file_table = NULL;
3995 for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
3996 struct fixed_file_table *table;
4000 if (copy_from_user(&fd, &fds[i], sizeof(fd)))
4002 /* allow sparse sets */
4008 table = &ctx->file_table[i >> IORING_FILE_TABLE_SHIFT];
4009 index = i & IORING_FILE_TABLE_MASK;
4010 table->files[index] = fget(fd);
4013 if (!table->files[index])
4016 * Don't allow io_uring instances to be registered. If UNIX
4017 * isn't enabled, then this causes a reference cycle and this
4018 * instance can never get freed. If UNIX is enabled we'll
4019 * handle it just fine, but there's still no point in allowing
4020 * a ring fd as it doesn't support regular read/write anyway.
4022 if (table->files[index]->f_op == &io_uring_fops) {
4023 fput(table->files[index]);
4030 for (i = 0; i < ctx->nr_user_files; i++) {
4033 file = io_file_from_index(ctx, i);
4037 for (i = 0; i < nr_tables; i++)
4038 kfree(ctx->file_table[i].files);
4040 kfree(ctx->file_table);
4041 ctx->file_table = NULL;
4042 ctx->nr_user_files = 0;
4046 ret = io_sqe_files_scm(ctx);
4048 io_sqe_files_unregister(ctx);
4053 static void io_sqe_file_unregister(struct io_ring_ctx *ctx, int index)
4055 #if defined(CONFIG_UNIX)
4056 struct file *file = io_file_from_index(ctx, index);
4057 struct sock *sock = ctx->ring_sock->sk;
4058 struct sk_buff_head list, *head = &sock->sk_receive_queue;
4059 struct sk_buff *skb;
4062 __skb_queue_head_init(&list);
4065 * Find the skb that holds this file in its SCM_RIGHTS. When found,
4066 * remove this entry and rearrange the file array.
4068 skb = skb_dequeue(head);
4070 struct scm_fp_list *fp;
4072 fp = UNIXCB(skb).fp;
4073 for (i = 0; i < fp->count; i++) {
4076 if (fp->fp[i] != file)
4079 unix_notinflight(fp->user, fp->fp[i]);
4080 left = fp->count - 1 - i;
4082 memmove(&fp->fp[i], &fp->fp[i + 1],
4083 left * sizeof(struct file *));
4090 __skb_queue_tail(&list, skb);
4100 __skb_queue_tail(&list, skb);
4102 skb = skb_dequeue(head);
4105 if (skb_peek(&list)) {
4106 spin_lock_irq(&head->lock);
4107 while ((skb = __skb_dequeue(&list)) != NULL)
4108 __skb_queue_tail(head, skb);
4109 spin_unlock_irq(&head->lock);
4112 fput(io_file_from_index(ctx, index));
4116 static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file,
4119 #if defined(CONFIG_UNIX)
4120 struct sock *sock = ctx->ring_sock->sk;
4121 struct sk_buff_head *head = &sock->sk_receive_queue;
4122 struct sk_buff *skb;
4125 * See if we can merge this file into an existing skb SCM_RIGHTS
4126 * file set. If there's no room, fall back to allocating a new skb
4127 * and filling it in.
4129 spin_lock_irq(&head->lock);
4130 skb = skb_peek(head);
4132 struct scm_fp_list *fpl = UNIXCB(skb).fp;
4134 if (fpl->count < SCM_MAX_FD) {
4135 __skb_unlink(skb, head);
4136 spin_unlock_irq(&head->lock);
4137 fpl->fp[fpl->count] = get_file(file);
4138 unix_inflight(fpl->user, fpl->fp[fpl->count]);
4140 spin_lock_irq(&head->lock);
4141 __skb_queue_head(head, skb);
4146 spin_unlock_irq(&head->lock);
4153 return __io_sqe_files_scm(ctx, 1, index);
4159 static int io_sqe_files_update(struct io_ring_ctx *ctx, void __user *arg,
4162 struct io_uring_files_update up;
4167 if (!ctx->file_table)
4171 if (copy_from_user(&up, arg, sizeof(up)))
4173 if (check_add_overflow(up.offset, nr_args, &done))
4175 if (done > ctx->nr_user_files)
4179 fds = (__s32 __user *) up.fds;
4181 struct fixed_file_table *table;
4185 if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
4189 i = array_index_nospec(up.offset, ctx->nr_user_files);
4190 table = &ctx->file_table[i >> IORING_FILE_TABLE_SHIFT];
4191 index = i & IORING_FILE_TABLE_MASK;
4192 if (table->files[index]) {
4193 io_sqe_file_unregister(ctx, i);
4194 table->files[index] = NULL;
4205 * Don't allow io_uring instances to be registered. If
4206 * UNIX isn't enabled, then this causes a reference
4207 * cycle and this instance can never get freed. If UNIX
4208 * is enabled we'll handle it just fine, but there's
4209 * still no point in allowing a ring fd as it doesn't
4210 * support regular read/write anyway.
4212 if (file->f_op == &io_uring_fops) {
4217 table->files[index] = file;
4218 err = io_sqe_file_register(ctx, file, i);
4227 return done ? done : err;
4230 static void io_put_work(struct io_wq_work *work)
4232 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
4237 static void io_get_work(struct io_wq_work *work)
4239 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
4241 refcount_inc(&req->refs);
4244 static int io_sq_offload_start(struct io_ring_ctx *ctx,
4245 struct io_uring_params *p)
4247 struct io_wq_data data;
4248 unsigned concurrency;
4251 init_waitqueue_head(&ctx->sqo_wait);
4252 mmgrab(current->mm);
4253 ctx->sqo_mm = current->mm;
4255 if (ctx->flags & IORING_SETUP_SQPOLL) {
4257 if (!capable(CAP_SYS_ADMIN))
4260 ctx->sq_thread_idle = msecs_to_jiffies(p->sq_thread_idle);
4261 if (!ctx->sq_thread_idle)
4262 ctx->sq_thread_idle = HZ;
4264 if (p->flags & IORING_SETUP_SQ_AFF) {
4265 int cpu = p->sq_thread_cpu;
4268 if (cpu >= nr_cpu_ids)
4270 if (!cpu_online(cpu))
4273 ctx->sqo_thread = kthread_create_on_cpu(io_sq_thread,
4277 ctx->sqo_thread = kthread_create(io_sq_thread, ctx,
4280 if (IS_ERR(ctx->sqo_thread)) {
4281 ret = PTR_ERR(ctx->sqo_thread);
4282 ctx->sqo_thread = NULL;
4285 wake_up_process(ctx->sqo_thread);
4286 } else if (p->flags & IORING_SETUP_SQ_AFF) {
4287 /* Can't have SQ_AFF without SQPOLL */
4292 data.mm = ctx->sqo_mm;
4293 data.user = ctx->user;
4294 data.creds = ctx->creds;
4295 data.get_work = io_get_work;
4296 data.put_work = io_put_work;
4298 /* Do QD, or 4 * CPUS, whatever is smallest */
4299 concurrency = min(ctx->sq_entries, 4 * num_online_cpus());
4300 ctx->io_wq = io_wq_create(concurrency, &data);
4301 if (IS_ERR(ctx->io_wq)) {
4302 ret = PTR_ERR(ctx->io_wq);
4309 io_finish_async(ctx);
4310 mmdrop(ctx->sqo_mm);
4315 static void io_unaccount_mem(struct user_struct *user, unsigned long nr_pages)
4317 atomic_long_sub(nr_pages, &user->locked_vm);
4320 static int io_account_mem(struct user_struct *user, unsigned long nr_pages)
4322 unsigned long page_limit, cur_pages, new_pages;
4324 /* Don't allow more pages than we can safely lock */
4325 page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
4328 cur_pages = atomic_long_read(&user->locked_vm);
4329 new_pages = cur_pages + nr_pages;
4330 if (new_pages > page_limit)
4332 } while (atomic_long_cmpxchg(&user->locked_vm, cur_pages,
4333 new_pages) != cur_pages);
4338 static void io_mem_free(void *ptr)
4345 page = virt_to_head_page(ptr);
4346 if (put_page_testzero(page))
4347 free_compound_page(page);
4350 static void *io_mem_alloc(size_t size)
4352 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP |
4355 return (void *) __get_free_pages(gfp_flags, get_order(size));
4358 static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries,
4361 struct io_rings *rings;
4362 size_t off, sq_array_size;
4364 off = struct_size(rings, cqes, cq_entries);
4365 if (off == SIZE_MAX)
4369 off = ALIGN(off, SMP_CACHE_BYTES);
4374 sq_array_size = array_size(sizeof(u32), sq_entries);
4375 if (sq_array_size == SIZE_MAX)
4378 if (check_add_overflow(off, sq_array_size, &off))
4387 static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries)
4391 pages = (size_t)1 << get_order(
4392 rings_size(sq_entries, cq_entries, NULL));
4393 pages += (size_t)1 << get_order(
4394 array_size(sizeof(struct io_uring_sqe), sq_entries));
4399 static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx)
4403 if (!ctx->user_bufs)
4406 for (i = 0; i < ctx->nr_user_bufs; i++) {
4407 struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
4409 for (j = 0; j < imu->nr_bvecs; j++)
4410 put_user_page(imu->bvec[j].bv_page);
4412 if (ctx->account_mem)
4413 io_unaccount_mem(ctx->user, imu->nr_bvecs);
4418 kfree(ctx->user_bufs);
4419 ctx->user_bufs = NULL;
4420 ctx->nr_user_bufs = 0;
4424 static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst,
4425 void __user *arg, unsigned index)
4427 struct iovec __user *src;
4429 #ifdef CONFIG_COMPAT
4431 struct compat_iovec __user *ciovs;
4432 struct compat_iovec ciov;
4434 ciovs = (struct compat_iovec __user *) arg;
4435 if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov)))
4438 dst->iov_base = (void __user *) (unsigned long) ciov.iov_base;
4439 dst->iov_len = ciov.iov_len;
4443 src = (struct iovec __user *) arg;
4444 if (copy_from_user(dst, &src[index], sizeof(*dst)))
4449 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
4452 struct vm_area_struct **vmas = NULL;
4453 struct page **pages = NULL;
4454 int i, j, got_pages = 0;
4459 if (!nr_args || nr_args > UIO_MAXIOV)
4462 ctx->user_bufs = kcalloc(nr_args, sizeof(struct io_mapped_ubuf),
4464 if (!ctx->user_bufs)
4467 for (i = 0; i < nr_args; i++) {
4468 struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
4469 unsigned long off, start, end, ubuf;
4474 ret = io_copy_iov(ctx, &iov, arg, i);
4479 * Don't impose further limits on the size and buffer
4480 * constraints here, we'll -EINVAL later when IO is
4481 * submitted if they are wrong.
4484 if (!iov.iov_base || !iov.iov_len)
4487 /* arbitrary limit, but we need something */
4488 if (iov.iov_len > SZ_1G)
4491 ubuf = (unsigned long) iov.iov_base;
4492 end = (ubuf + iov.iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
4493 start = ubuf >> PAGE_SHIFT;
4494 nr_pages = end - start;
4496 if (ctx->account_mem) {
4497 ret = io_account_mem(ctx->user, nr_pages);
4503 if (!pages || nr_pages > got_pages) {
4506 pages = kvmalloc_array(nr_pages, sizeof(struct page *),
4508 vmas = kvmalloc_array(nr_pages,
4509 sizeof(struct vm_area_struct *),
4511 if (!pages || !vmas) {
4513 if (ctx->account_mem)
4514 io_unaccount_mem(ctx->user, nr_pages);
4517 got_pages = nr_pages;
4520 imu->bvec = kvmalloc_array(nr_pages, sizeof(struct bio_vec),
4524 if (ctx->account_mem)
4525 io_unaccount_mem(ctx->user, nr_pages);
4530 down_read(¤t->mm->mmap_sem);
4531 pret = get_user_pages(ubuf, nr_pages,
4532 FOLL_WRITE | FOLL_LONGTERM,
4534 if (pret == nr_pages) {
4535 /* don't support file backed memory */
4536 for (j = 0; j < nr_pages; j++) {
4537 struct vm_area_struct *vma = vmas[j];
4540 !is_file_hugepages(vma->vm_file)) {
4546 ret = pret < 0 ? pret : -EFAULT;
4548 up_read(¤t->mm->mmap_sem);
4551 * if we did partial map, or found file backed vmas,
4552 * release any pages we did get
4555 put_user_pages(pages, pret);
4556 if (ctx->account_mem)
4557 io_unaccount_mem(ctx->user, nr_pages);
4562 off = ubuf & ~PAGE_MASK;
4564 for (j = 0; j < nr_pages; j++) {
4567 vec_len = min_t(size_t, size, PAGE_SIZE - off);
4568 imu->bvec[j].bv_page = pages[j];
4569 imu->bvec[j].bv_len = vec_len;
4570 imu->bvec[j].bv_offset = off;
4574 /* store original address for later verification */
4576 imu->len = iov.iov_len;
4577 imu->nr_bvecs = nr_pages;
4579 ctx->nr_user_bufs++;
4587 io_sqe_buffer_unregister(ctx);
4591 static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg)
4593 __s32 __user *fds = arg;
4599 if (copy_from_user(&fd, fds, sizeof(*fds)))
4602 ctx->cq_ev_fd = eventfd_ctx_fdget(fd);
4603 if (IS_ERR(ctx->cq_ev_fd)) {
4604 int ret = PTR_ERR(ctx->cq_ev_fd);
4605 ctx->cq_ev_fd = NULL;
4612 static int io_eventfd_unregister(struct io_ring_ctx *ctx)
4614 if (ctx->cq_ev_fd) {
4615 eventfd_ctx_put(ctx->cq_ev_fd);
4616 ctx->cq_ev_fd = NULL;
4623 static void io_ring_ctx_free(struct io_ring_ctx *ctx)
4625 io_finish_async(ctx);
4627 mmdrop(ctx->sqo_mm);
4629 io_iopoll_reap_events(ctx);
4630 io_sqe_buffer_unregister(ctx);
4631 io_sqe_files_unregister(ctx);
4632 io_eventfd_unregister(ctx);
4634 #if defined(CONFIG_UNIX)
4635 if (ctx->ring_sock) {
4636 ctx->ring_sock->file = NULL; /* so that iput() is called */
4637 sock_release(ctx->ring_sock);
4641 io_mem_free(ctx->rings);
4642 io_mem_free(ctx->sq_sqes);
4644 percpu_ref_exit(&ctx->refs);
4645 if (ctx->account_mem)
4646 io_unaccount_mem(ctx->user,
4647 ring_pages(ctx->sq_entries, ctx->cq_entries));
4648 free_uid(ctx->user);
4649 put_cred(ctx->creds);
4650 kfree(ctx->completions);
4651 kfree(ctx->cancel_hash);
4652 kmem_cache_free(req_cachep, ctx->fallback_req);
4656 static __poll_t io_uring_poll(struct file *file, poll_table *wait)
4658 struct io_ring_ctx *ctx = file->private_data;
4661 poll_wait(file, &ctx->cq_wait, wait);
4663 * synchronizes with barrier from wq_has_sleeper call in
4667 if (READ_ONCE(ctx->rings->sq.tail) - ctx->cached_sq_head !=
4668 ctx->rings->sq_ring_entries)
4669 mask |= EPOLLOUT | EPOLLWRNORM;
4670 if (READ_ONCE(ctx->rings->cq.head) != ctx->cached_cq_tail)
4671 mask |= EPOLLIN | EPOLLRDNORM;
4676 static int io_uring_fasync(int fd, struct file *file, int on)
4678 struct io_ring_ctx *ctx = file->private_data;
4680 return fasync_helper(fd, file, on, &ctx->cq_fasync);
4683 static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
4685 mutex_lock(&ctx->uring_lock);
4686 percpu_ref_kill(&ctx->refs);
4687 mutex_unlock(&ctx->uring_lock);
4689 io_kill_timeouts(ctx);
4690 io_poll_remove_all(ctx);
4693 io_wq_cancel_all(ctx->io_wq);
4695 io_iopoll_reap_events(ctx);
4696 /* if we failed setting up the ctx, we might not have any rings */
4698 io_cqring_overflow_flush(ctx, true);
4699 wait_for_completion(&ctx->completions[0]);
4700 io_ring_ctx_free(ctx);
4703 static int io_uring_release(struct inode *inode, struct file *file)
4705 struct io_ring_ctx *ctx = file->private_data;
4707 file->private_data = NULL;
4708 io_ring_ctx_wait_and_kill(ctx);
4712 static void io_uring_cancel_files(struct io_ring_ctx *ctx,
4713 struct files_struct *files)
4715 struct io_kiocb *req;
4718 while (!list_empty_careful(&ctx->inflight_list)) {
4719 struct io_kiocb *cancel_req = NULL;
4721 spin_lock_irq(&ctx->inflight_lock);
4722 list_for_each_entry(req, &ctx->inflight_list, inflight_entry) {
4723 if (req->work.files != files)
4725 /* req is being completed, ignore */
4726 if (!refcount_inc_not_zero(&req->refs))
4732 prepare_to_wait(&ctx->inflight_wait, &wait,
4733 TASK_UNINTERRUPTIBLE);
4734 spin_unlock_irq(&ctx->inflight_lock);
4736 /* We need to keep going until we don't find a matching req */
4740 io_wq_cancel_work(ctx->io_wq, &cancel_req->work);
4741 io_put_req(cancel_req);
4744 finish_wait(&ctx->inflight_wait, &wait);
4747 static int io_uring_flush(struct file *file, void *data)
4749 struct io_ring_ctx *ctx = file->private_data;
4751 io_uring_cancel_files(ctx, data);
4752 if (fatal_signal_pending(current) || (current->flags & PF_EXITING)) {
4753 io_cqring_overflow_flush(ctx, true);
4754 io_wq_cancel_all(ctx->io_wq);
4759 static void *io_uring_validate_mmap_request(struct file *file,
4760 loff_t pgoff, size_t sz)
4762 struct io_ring_ctx *ctx = file->private_data;
4763 loff_t offset = pgoff << PAGE_SHIFT;
4768 case IORING_OFF_SQ_RING:
4769 case IORING_OFF_CQ_RING:
4772 case IORING_OFF_SQES:
4776 return ERR_PTR(-EINVAL);
4779 page = virt_to_head_page(ptr);
4780 if (sz > page_size(page))
4781 return ERR_PTR(-EINVAL);
4788 static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
4790 size_t sz = vma->vm_end - vma->vm_start;
4794 ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz);
4796 return PTR_ERR(ptr);
4798 pfn = virt_to_phys(ptr) >> PAGE_SHIFT;
4799 return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot);
4802 #else /* !CONFIG_MMU */
4804 static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
4806 return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -EINVAL;
4809 static unsigned int io_uring_nommu_mmap_capabilities(struct file *file)
4811 return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE;
4814 static unsigned long io_uring_nommu_get_unmapped_area(struct file *file,
4815 unsigned long addr, unsigned long len,
4816 unsigned long pgoff, unsigned long flags)
4820 ptr = io_uring_validate_mmap_request(file, pgoff, len);
4822 return PTR_ERR(ptr);
4824 return (unsigned long) ptr;
4827 #endif /* !CONFIG_MMU */
4829 SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
4830 u32, min_complete, u32, flags, const sigset_t __user *, sig,
4833 struct io_ring_ctx *ctx;
4838 if (flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP))
4846 if (f.file->f_op != &io_uring_fops)
4850 ctx = f.file->private_data;
4851 if (!percpu_ref_tryget(&ctx->refs))
4855 * For SQ polling, the thread will do all submissions and completions.
4856 * Just return the requested submit count, and wake the thread if
4860 if (ctx->flags & IORING_SETUP_SQPOLL) {
4861 if (!list_empty_careful(&ctx->cq_overflow_list))
4862 io_cqring_overflow_flush(ctx, false);
4863 if (flags & IORING_ENTER_SQ_WAKEUP)
4864 wake_up(&ctx->sqo_wait);
4865 submitted = to_submit;
4866 } else if (to_submit) {
4867 struct mm_struct *cur_mm;
4869 to_submit = min(to_submit, ctx->sq_entries);
4870 mutex_lock(&ctx->uring_lock);
4871 /* already have mm, so io_submit_sqes() won't try to grab it */
4872 cur_mm = ctx->sqo_mm;
4873 submitted = io_submit_sqes(ctx, to_submit, f.file, fd,
4875 mutex_unlock(&ctx->uring_lock);
4877 if (flags & IORING_ENTER_GETEVENTS) {
4878 unsigned nr_events = 0;
4880 min_complete = min(min_complete, ctx->cq_entries);
4882 if (ctx->flags & IORING_SETUP_IOPOLL) {
4883 ret = io_iopoll_check(ctx, &nr_events, min_complete);
4885 ret = io_cqring_wait(ctx, min_complete, sig, sigsz);
4889 percpu_ref_put(&ctx->refs);
4892 return submitted ? submitted : ret;
4895 static const struct file_operations io_uring_fops = {
4896 .release = io_uring_release,
4897 .flush = io_uring_flush,
4898 .mmap = io_uring_mmap,
4900 .get_unmapped_area = io_uring_nommu_get_unmapped_area,
4901 .mmap_capabilities = io_uring_nommu_mmap_capabilities,
4903 .poll = io_uring_poll,
4904 .fasync = io_uring_fasync,
4907 static int io_allocate_scq_urings(struct io_ring_ctx *ctx,
4908 struct io_uring_params *p)
4910 struct io_rings *rings;
4911 size_t size, sq_array_offset;
4913 size = rings_size(p->sq_entries, p->cq_entries, &sq_array_offset);
4914 if (size == SIZE_MAX)
4917 rings = io_mem_alloc(size);
4922 ctx->sq_array = (u32 *)((char *)rings + sq_array_offset);
4923 rings->sq_ring_mask = p->sq_entries - 1;
4924 rings->cq_ring_mask = p->cq_entries - 1;
4925 rings->sq_ring_entries = p->sq_entries;
4926 rings->cq_ring_entries = p->cq_entries;
4927 ctx->sq_mask = rings->sq_ring_mask;
4928 ctx->cq_mask = rings->cq_ring_mask;
4929 ctx->sq_entries = rings->sq_ring_entries;
4930 ctx->cq_entries = rings->cq_ring_entries;
4932 size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
4933 if (size == SIZE_MAX) {
4934 io_mem_free(ctx->rings);
4939 ctx->sq_sqes = io_mem_alloc(size);
4940 if (!ctx->sq_sqes) {
4941 io_mem_free(ctx->rings);
4950 * Allocate an anonymous fd, this is what constitutes the application
4951 * visible backing of an io_uring instance. The application mmaps this
4952 * fd to gain access to the SQ/CQ ring details. If UNIX sockets are enabled,
4953 * we have to tie this fd to a socket for file garbage collection purposes.
4955 static int io_uring_get_fd(struct io_ring_ctx *ctx)
4960 #if defined(CONFIG_UNIX)
4961 ret = sock_create_kern(&init_net, PF_UNIX, SOCK_RAW, IPPROTO_IP,
4967 ret = get_unused_fd_flags(O_RDWR | O_CLOEXEC);
4971 file = anon_inode_getfile("[io_uring]", &io_uring_fops, ctx,
4972 O_RDWR | O_CLOEXEC);
4975 ret = PTR_ERR(file);
4979 #if defined(CONFIG_UNIX)
4980 ctx->ring_sock->file = file;
4981 ctx->ring_sock->sk->sk_user_data = ctx;
4983 fd_install(ret, file);
4986 #if defined(CONFIG_UNIX)
4987 sock_release(ctx->ring_sock);
4988 ctx->ring_sock = NULL;
4993 static int io_uring_create(unsigned entries, struct io_uring_params *p)
4995 struct user_struct *user = NULL;
4996 struct io_ring_ctx *ctx;
5000 if (!entries || entries > IORING_MAX_ENTRIES)
5004 * Use twice as many entries for the CQ ring. It's possible for the
5005 * application to drive a higher depth than the size of the SQ ring,
5006 * since the sqes are only used at submission time. This allows for
5007 * some flexibility in overcommitting a bit. If the application has
5008 * set IORING_SETUP_CQSIZE, it will have passed in the desired number
5009 * of CQ ring entries manually.
5011 p->sq_entries = roundup_pow_of_two(entries);
5012 if (p->flags & IORING_SETUP_CQSIZE) {
5014 * If IORING_SETUP_CQSIZE is set, we do the same roundup
5015 * to a power-of-two, if it isn't already. We do NOT impose
5016 * any cq vs sq ring sizing.
5018 if (p->cq_entries < p->sq_entries || p->cq_entries > IORING_MAX_CQ_ENTRIES)
5020 p->cq_entries = roundup_pow_of_two(p->cq_entries);
5022 p->cq_entries = 2 * p->sq_entries;
5025 user = get_uid(current_user());
5026 account_mem = !capable(CAP_IPC_LOCK);
5029 ret = io_account_mem(user,
5030 ring_pages(p->sq_entries, p->cq_entries));
5037 ctx = io_ring_ctx_alloc(p);
5040 io_unaccount_mem(user, ring_pages(p->sq_entries,
5045 ctx->compat = in_compat_syscall();
5046 ctx->account_mem = account_mem;
5048 ctx->creds = get_current_cred();
5050 ret = io_allocate_scq_urings(ctx, p);
5054 ret = io_sq_offload_start(ctx, p);
5058 memset(&p->sq_off, 0, sizeof(p->sq_off));
5059 p->sq_off.head = offsetof(struct io_rings, sq.head);
5060 p->sq_off.tail = offsetof(struct io_rings, sq.tail);
5061 p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask);
5062 p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries);
5063 p->sq_off.flags = offsetof(struct io_rings, sq_flags);
5064 p->sq_off.dropped = offsetof(struct io_rings, sq_dropped);
5065 p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings;
5067 memset(&p->cq_off, 0, sizeof(p->cq_off));
5068 p->cq_off.head = offsetof(struct io_rings, cq.head);
5069 p->cq_off.tail = offsetof(struct io_rings, cq.tail);
5070 p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask);
5071 p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries);
5072 p->cq_off.overflow = offsetof(struct io_rings, cq_overflow);
5073 p->cq_off.cqes = offsetof(struct io_rings, cqes);
5076 * Install ring fd as the very last thing, so we don't risk someone
5077 * having closed it before we finish setup
5079 ret = io_uring_get_fd(ctx);
5083 p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP |
5084 IORING_FEAT_SUBMIT_STABLE;
5085 trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags);
5088 io_ring_ctx_wait_and_kill(ctx);
5093 * Sets up an aio uring context, and returns the fd. Applications asks for a
5094 * ring size, we return the actual sq/cq ring sizes (among other things) in the
5095 * params structure passed in.
5097 static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
5099 struct io_uring_params p;
5103 if (copy_from_user(&p, params, sizeof(p)))
5105 for (i = 0; i < ARRAY_SIZE(p.resv); i++) {
5110 if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL |
5111 IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE))
5114 ret = io_uring_create(entries, &p);
5118 if (copy_to_user(params, &p, sizeof(p)))
5124 SYSCALL_DEFINE2(io_uring_setup, u32, entries,
5125 struct io_uring_params __user *, params)
5127 return io_uring_setup(entries, params);
5130 static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
5131 void __user *arg, unsigned nr_args)
5132 __releases(ctx->uring_lock)
5133 __acquires(ctx->uring_lock)
5138 * We're inside the ring mutex, if the ref is already dying, then
5139 * someone else killed the ctx or is already going through
5140 * io_uring_register().
5142 if (percpu_ref_is_dying(&ctx->refs))
5145 percpu_ref_kill(&ctx->refs);
5148 * Drop uring mutex before waiting for references to exit. If another
5149 * thread is currently inside io_uring_enter() it might need to grab
5150 * the uring_lock to make progress. If we hold it here across the drain
5151 * wait, then we can deadlock. It's safe to drop the mutex here, since
5152 * no new references will come in after we've killed the percpu ref.
5154 mutex_unlock(&ctx->uring_lock);
5155 wait_for_completion(&ctx->completions[0]);
5156 mutex_lock(&ctx->uring_lock);
5159 case IORING_REGISTER_BUFFERS:
5160 ret = io_sqe_buffer_register(ctx, arg, nr_args);
5162 case IORING_UNREGISTER_BUFFERS:
5166 ret = io_sqe_buffer_unregister(ctx);
5168 case IORING_REGISTER_FILES:
5169 ret = io_sqe_files_register(ctx, arg, nr_args);
5171 case IORING_UNREGISTER_FILES:
5175 ret = io_sqe_files_unregister(ctx);
5177 case IORING_REGISTER_FILES_UPDATE:
5178 ret = io_sqe_files_update(ctx, arg, nr_args);
5180 case IORING_REGISTER_EVENTFD:
5184 ret = io_eventfd_register(ctx, arg);
5186 case IORING_UNREGISTER_EVENTFD:
5190 ret = io_eventfd_unregister(ctx);
5197 /* bring the ctx back to life */
5198 reinit_completion(&ctx->completions[0]);
5199 percpu_ref_reinit(&ctx->refs);
5203 SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode,
5204 void __user *, arg, unsigned int, nr_args)
5206 struct io_ring_ctx *ctx;
5215 if (f.file->f_op != &io_uring_fops)
5218 ctx = f.file->private_data;
5220 mutex_lock(&ctx->uring_lock);
5221 ret = __io_uring_register(ctx, opcode, arg, nr_args);
5222 mutex_unlock(&ctx->uring_lock);
5223 trace_io_uring_register(ctx, opcode, ctx->nr_user_files, ctx->nr_user_bufs,
5224 ctx->cq_ev_fd != NULL, ret);
5230 static int __init io_uring_init(void)
5232 req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC);
5235 __initcall(io_uring_init);