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:
584 /* only regular files should be hashed for writes */
585 if (req->flags & REQ_F_ISREG)
588 case IORING_OP_READV:
589 case IORING_OP_READ_FIXED:
590 case IORING_OP_SENDMSG:
591 case IORING_OP_RECVMSG:
592 case IORING_OP_ACCEPT:
593 case IORING_OP_POLL_ADD:
594 case IORING_OP_CONNECT:
596 * We know REQ_F_ISREG is not set on some of these
597 * opcodes, but this enables us to keep the check in
600 if (!(req->flags & REQ_F_ISREG))
601 req->work.flags |= IO_WQ_WORK_UNBOUND;
604 if (io_sqe_needs_user(req->sqe))
605 req->work.flags |= IO_WQ_WORK_NEEDS_USER;
608 *link = io_prep_linked_timeout(req);
612 static inline void io_queue_async_work(struct io_kiocb *req)
614 struct io_ring_ctx *ctx = req->ctx;
615 struct io_kiocb *link;
618 do_hashed = io_prep_async_work(req, &link);
620 trace_io_uring_queue_async_work(ctx, do_hashed, req, &req->work,
623 io_wq_enqueue(ctx->io_wq, &req->work);
625 io_wq_enqueue_hashed(ctx->io_wq, &req->work,
626 file_inode(req->file));
630 io_queue_linked_timeout(link);
633 static void io_kill_timeout(struct io_kiocb *req)
637 ret = hrtimer_try_to_cancel(&req->io->timeout.timer);
639 atomic_inc(&req->ctx->cq_timeouts);
640 list_del_init(&req->list);
641 io_cqring_fill_event(req, 0);
646 static void io_kill_timeouts(struct io_ring_ctx *ctx)
648 struct io_kiocb *req, *tmp;
650 spin_lock_irq(&ctx->completion_lock);
651 list_for_each_entry_safe(req, tmp, &ctx->timeout_list, list)
652 io_kill_timeout(req);
653 spin_unlock_irq(&ctx->completion_lock);
656 static void io_commit_cqring(struct io_ring_ctx *ctx)
658 struct io_kiocb *req;
660 while ((req = io_get_timeout_req(ctx)) != NULL)
661 io_kill_timeout(req);
663 __io_commit_cqring(ctx);
665 while ((req = io_get_deferred_req(ctx)) != NULL) {
666 req->flags |= REQ_F_IO_DRAINED;
667 io_queue_async_work(req);
671 static struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx)
673 struct io_rings *rings = ctx->rings;
676 tail = ctx->cached_cq_tail;
678 * writes to the cq entry need to come after reading head; the
679 * control dependency is enough as we're using WRITE_ONCE to
682 if (tail - READ_ONCE(rings->cq.head) == rings->cq_ring_entries)
685 ctx->cached_cq_tail++;
686 return &rings->cqes[tail & ctx->cq_mask];
689 static void io_cqring_ev_posted(struct io_ring_ctx *ctx)
691 if (waitqueue_active(&ctx->wait))
693 if (waitqueue_active(&ctx->sqo_wait))
694 wake_up(&ctx->sqo_wait);
696 eventfd_signal(ctx->cq_ev_fd, 1);
699 /* Returns true if there are no backlogged entries after the flush */
700 static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force)
702 struct io_rings *rings = ctx->rings;
703 struct io_uring_cqe *cqe;
704 struct io_kiocb *req;
709 if (list_empty_careful(&ctx->cq_overflow_list))
711 if ((ctx->cached_cq_tail - READ_ONCE(rings->cq.head) ==
712 rings->cq_ring_entries))
716 spin_lock_irqsave(&ctx->completion_lock, flags);
718 /* if force is set, the ring is going away. always drop after that */
720 ctx->cq_overflow_flushed = true;
723 while (!list_empty(&ctx->cq_overflow_list)) {
724 cqe = io_get_cqring(ctx);
728 req = list_first_entry(&ctx->cq_overflow_list, struct io_kiocb,
730 list_move(&req->list, &list);
732 WRITE_ONCE(cqe->user_data, req->user_data);
733 WRITE_ONCE(cqe->res, req->result);
734 WRITE_ONCE(cqe->flags, 0);
736 WRITE_ONCE(ctx->rings->cq_overflow,
737 atomic_inc_return(&ctx->cached_cq_overflow));
741 io_commit_cqring(ctx);
742 spin_unlock_irqrestore(&ctx->completion_lock, flags);
743 io_cqring_ev_posted(ctx);
745 while (!list_empty(&list)) {
746 req = list_first_entry(&list, struct io_kiocb, list);
747 list_del(&req->list);
754 static void io_cqring_fill_event(struct io_kiocb *req, long res)
756 struct io_ring_ctx *ctx = req->ctx;
757 struct io_uring_cqe *cqe;
759 trace_io_uring_complete(ctx, req->user_data, res);
762 * If we can't get a cq entry, userspace overflowed the
763 * submission (by quite a lot). Increment the overflow count in
766 cqe = io_get_cqring(ctx);
768 WRITE_ONCE(cqe->user_data, req->user_data);
769 WRITE_ONCE(cqe->res, res);
770 WRITE_ONCE(cqe->flags, 0);
771 } else if (ctx->cq_overflow_flushed) {
772 WRITE_ONCE(ctx->rings->cq_overflow,
773 atomic_inc_return(&ctx->cached_cq_overflow));
775 refcount_inc(&req->refs);
777 list_add_tail(&req->list, &ctx->cq_overflow_list);
781 static void io_cqring_add_event(struct io_kiocb *req, long res)
783 struct io_ring_ctx *ctx = req->ctx;
786 spin_lock_irqsave(&ctx->completion_lock, flags);
787 io_cqring_fill_event(req, res);
788 io_commit_cqring(ctx);
789 spin_unlock_irqrestore(&ctx->completion_lock, flags);
791 io_cqring_ev_posted(ctx);
794 static inline bool io_is_fallback_req(struct io_kiocb *req)
796 return req == (struct io_kiocb *)
797 ((unsigned long) req->ctx->fallback_req & ~1UL);
800 static struct io_kiocb *io_get_fallback_req(struct io_ring_ctx *ctx)
802 struct io_kiocb *req;
804 req = ctx->fallback_req;
805 if (!test_and_set_bit_lock(0, (unsigned long *) ctx->fallback_req))
811 static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx,
812 struct io_submit_state *state)
814 gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
815 struct io_kiocb *req;
817 if (!percpu_ref_tryget(&ctx->refs))
821 req = kmem_cache_alloc(req_cachep, gfp);
824 } else if (!state->free_reqs) {
828 sz = min_t(size_t, state->ios_left, ARRAY_SIZE(state->reqs));
829 ret = kmem_cache_alloc_bulk(req_cachep, gfp, sz, state->reqs);
832 * Bulk alloc is all-or-nothing. If we fail to get a batch,
833 * retry single alloc to be on the safe side.
835 if (unlikely(ret <= 0)) {
836 state->reqs[0] = kmem_cache_alloc(req_cachep, gfp);
841 state->free_reqs = ret - 1;
843 req = state->reqs[0];
845 req = state->reqs[state->cur_req];
852 req->ring_file = NULL;
856 /* one is dropped after submission, the other at completion */
857 refcount_set(&req->refs, 2);
859 INIT_IO_WORK(&req->work, io_wq_submit_work);
862 req = io_get_fallback_req(ctx);
865 percpu_ref_put(&ctx->refs);
869 static void io_free_req_many(struct io_ring_ctx *ctx, void **reqs, int *nr)
872 kmem_cache_free_bulk(req_cachep, *nr, reqs);
873 percpu_ref_put_many(&ctx->refs, *nr);
878 static void __io_free_req(struct io_kiocb *req)
880 struct io_ring_ctx *ctx = req->ctx;
884 if (req->file && !(req->flags & REQ_F_FIXED_FILE))
886 if (req->flags & REQ_F_INFLIGHT) {
889 spin_lock_irqsave(&ctx->inflight_lock, flags);
890 list_del(&req->inflight_entry);
891 if (waitqueue_active(&ctx->inflight_wait))
892 wake_up(&ctx->inflight_wait);
893 spin_unlock_irqrestore(&ctx->inflight_lock, flags);
895 percpu_ref_put(&ctx->refs);
896 if (likely(!io_is_fallback_req(req)))
897 kmem_cache_free(req_cachep, req);
899 clear_bit_unlock(0, (unsigned long *) ctx->fallback_req);
902 static bool io_link_cancel_timeout(struct io_kiocb *req)
904 struct io_ring_ctx *ctx = req->ctx;
907 ret = hrtimer_try_to_cancel(&req->io->timeout.timer);
909 io_cqring_fill_event(req, -ECANCELED);
910 io_commit_cqring(ctx);
911 req->flags &= ~REQ_F_LINK;
919 static void io_req_link_next(struct io_kiocb *req, struct io_kiocb **nxtptr)
921 struct io_ring_ctx *ctx = req->ctx;
922 bool wake_ev = false;
924 /* Already got next link */
925 if (req->flags & REQ_F_LINK_NEXT)
929 * The list should never be empty when we are called here. But could
930 * potentially happen if the chain is messed up, check to be on the
933 while (!list_empty(&req->link_list)) {
934 struct io_kiocb *nxt = list_first_entry(&req->link_list,
935 struct io_kiocb, link_list);
937 if (unlikely((req->flags & REQ_F_LINK_TIMEOUT) &&
938 (nxt->flags & REQ_F_TIMEOUT))) {
939 list_del_init(&nxt->link_list);
940 wake_ev |= io_link_cancel_timeout(nxt);
941 req->flags &= ~REQ_F_LINK_TIMEOUT;
945 list_del_init(&req->link_list);
946 if (!list_empty(&nxt->link_list))
947 nxt->flags |= REQ_F_LINK;
952 req->flags |= REQ_F_LINK_NEXT;
954 io_cqring_ev_posted(ctx);
958 * Called if REQ_F_LINK is set, and we fail the head request
960 static void io_fail_links(struct io_kiocb *req)
962 struct io_ring_ctx *ctx = req->ctx;
965 spin_lock_irqsave(&ctx->completion_lock, flags);
967 while (!list_empty(&req->link_list)) {
968 struct io_kiocb *link = list_first_entry(&req->link_list,
969 struct io_kiocb, link_list);
971 list_del_init(&link->link_list);
972 trace_io_uring_fail_link(req, link);
974 if ((req->flags & REQ_F_LINK_TIMEOUT) &&
975 link->sqe->opcode == IORING_OP_LINK_TIMEOUT) {
976 io_link_cancel_timeout(link);
978 io_cqring_fill_event(link, -ECANCELED);
979 __io_double_put_req(link);
981 req->flags &= ~REQ_F_LINK_TIMEOUT;
984 io_commit_cqring(ctx);
985 spin_unlock_irqrestore(&ctx->completion_lock, flags);
986 io_cqring_ev_posted(ctx);
989 static void io_req_find_next(struct io_kiocb *req, struct io_kiocb **nxt)
991 if (likely(!(req->flags & REQ_F_LINK)))
995 * If LINK is set, we have dependent requests in this chain. If we
996 * didn't fail this request, queue the first one up, moving any other
997 * dependencies to the next request. In case of failure, fail the rest
1000 if (req->flags & REQ_F_FAIL_LINK) {
1002 } else if ((req->flags & (REQ_F_LINK_TIMEOUT | REQ_F_COMP_LOCKED)) ==
1003 REQ_F_LINK_TIMEOUT) {
1004 struct io_ring_ctx *ctx = req->ctx;
1005 unsigned long flags;
1008 * If this is a timeout link, we could be racing with the
1009 * timeout timer. Grab the completion lock for this case to
1010 * protect against that.
1012 spin_lock_irqsave(&ctx->completion_lock, flags);
1013 io_req_link_next(req, nxt);
1014 spin_unlock_irqrestore(&ctx->completion_lock, flags);
1016 io_req_link_next(req, nxt);
1020 static void io_free_req(struct io_kiocb *req)
1022 struct io_kiocb *nxt = NULL;
1024 io_req_find_next(req, &nxt);
1028 io_queue_async_work(nxt);
1032 * Drop reference to request, return next in chain (if there is one) if this
1033 * was the last reference to this request.
1035 __attribute__((nonnull))
1036 static void io_put_req_find_next(struct io_kiocb *req, struct io_kiocb **nxtptr)
1038 io_req_find_next(req, nxtptr);
1040 if (refcount_dec_and_test(&req->refs))
1044 static void io_put_req(struct io_kiocb *req)
1046 if (refcount_dec_and_test(&req->refs))
1051 * Must only be used if we don't need to care about links, usually from
1052 * within the completion handling itself.
1054 static void __io_double_put_req(struct io_kiocb *req)
1056 /* drop both submit and complete references */
1057 if (refcount_sub_and_test(2, &req->refs))
1061 static void io_double_put_req(struct io_kiocb *req)
1063 /* drop both submit and complete references */
1064 if (refcount_sub_and_test(2, &req->refs))
1068 static unsigned io_cqring_events(struct io_ring_ctx *ctx, bool noflush)
1070 struct io_rings *rings = ctx->rings;
1073 * noflush == true is from the waitqueue handler, just ensure we wake
1074 * up the task, and the next invocation will flush the entries. We
1075 * cannot safely to it from here.
1077 if (noflush && !list_empty(&ctx->cq_overflow_list))
1080 io_cqring_overflow_flush(ctx, false);
1082 /* See comment at the top of this file */
1084 return READ_ONCE(rings->cq.tail) - READ_ONCE(rings->cq.head);
1087 static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
1089 struct io_rings *rings = ctx->rings;
1091 /* make sure SQ entry isn't read before tail */
1092 return smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head;
1096 * Find and free completed poll iocbs
1098 static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
1099 struct list_head *done)
1101 void *reqs[IO_IOPOLL_BATCH];
1102 struct io_kiocb *req;
1106 while (!list_empty(done)) {
1107 req = list_first_entry(done, struct io_kiocb, list);
1108 list_del(&req->list);
1110 io_cqring_fill_event(req, req->result);
1113 if (refcount_dec_and_test(&req->refs)) {
1114 /* If we're not using fixed files, we have to pair the
1115 * completion part with the file put. Use regular
1116 * completions for those, only batch free for fixed
1117 * file and non-linked commands.
1119 if (((req->flags & (REQ_F_FIXED_FILE|REQ_F_LINK)) ==
1120 REQ_F_FIXED_FILE) && !io_is_fallback_req(req) &&
1122 reqs[to_free++] = req;
1123 if (to_free == ARRAY_SIZE(reqs))
1124 io_free_req_many(ctx, reqs, &to_free);
1131 io_commit_cqring(ctx);
1132 io_free_req_many(ctx, reqs, &to_free);
1135 static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
1138 struct io_kiocb *req, *tmp;
1144 * Only spin for completions if we don't have multiple devices hanging
1145 * off our complete list, and we're under the requested amount.
1147 spin = !ctx->poll_multi_file && *nr_events < min;
1150 list_for_each_entry_safe(req, tmp, &ctx->poll_list, list) {
1151 struct kiocb *kiocb = &req->rw;
1154 * Move completed entries to our local list. If we find a
1155 * request that requires polling, break out and complete
1156 * the done list first, if we have entries there.
1158 if (req->flags & REQ_F_IOPOLL_COMPLETED) {
1159 list_move_tail(&req->list, &done);
1162 if (!list_empty(&done))
1165 ret = kiocb->ki_filp->f_op->iopoll(kiocb, spin);
1174 if (!list_empty(&done))
1175 io_iopoll_complete(ctx, nr_events, &done);
1181 * Poll for a mininum of 'min' events. Note that if min == 0 we consider that a
1182 * non-spinning poll check - we'll still enter the driver poll loop, but only
1183 * as a non-spinning completion check.
1185 static int io_iopoll_getevents(struct io_ring_ctx *ctx, unsigned int *nr_events,
1188 while (!list_empty(&ctx->poll_list) && !need_resched()) {
1191 ret = io_do_iopoll(ctx, nr_events, min);
1194 if (!min || *nr_events >= min)
1202 * We can't just wait for polled events to come to us, we have to actively
1203 * find and complete them.
1205 static void io_iopoll_reap_events(struct io_ring_ctx *ctx)
1207 if (!(ctx->flags & IORING_SETUP_IOPOLL))
1210 mutex_lock(&ctx->uring_lock);
1211 while (!list_empty(&ctx->poll_list)) {
1212 unsigned int nr_events = 0;
1214 io_iopoll_getevents(ctx, &nr_events, 1);
1217 * Ensure we allow local-to-the-cpu processing to take place,
1218 * in this case we need to ensure that we reap all events.
1222 mutex_unlock(&ctx->uring_lock);
1225 static int __io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events,
1228 int iters = 0, ret = 0;
1234 * Don't enter poll loop if we already have events pending.
1235 * If we do, we can potentially be spinning for commands that
1236 * already triggered a CQE (eg in error).
1238 if (io_cqring_events(ctx, false))
1242 * If a submit got punted to a workqueue, we can have the
1243 * application entering polling for a command before it gets
1244 * issued. That app will hold the uring_lock for the duration
1245 * of the poll right here, so we need to take a breather every
1246 * now and then to ensure that the issue has a chance to add
1247 * the poll to the issued list. Otherwise we can spin here
1248 * forever, while the workqueue is stuck trying to acquire the
1251 if (!(++iters & 7)) {
1252 mutex_unlock(&ctx->uring_lock);
1253 mutex_lock(&ctx->uring_lock);
1256 if (*nr_events < min)
1257 tmin = min - *nr_events;
1259 ret = io_iopoll_getevents(ctx, nr_events, tmin);
1263 } while (min && !*nr_events && !need_resched());
1268 static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events,
1274 * We disallow the app entering submit/complete with polling, but we
1275 * still need to lock the ring to prevent racing with polled issue
1276 * that got punted to a workqueue.
1278 mutex_lock(&ctx->uring_lock);
1279 ret = __io_iopoll_check(ctx, nr_events, min);
1280 mutex_unlock(&ctx->uring_lock);
1284 static void kiocb_end_write(struct io_kiocb *req)
1287 * Tell lockdep we inherited freeze protection from submission
1290 if (req->flags & REQ_F_ISREG) {
1291 struct inode *inode = file_inode(req->file);
1293 __sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
1295 file_end_write(req->file);
1298 static inline void req_set_fail_links(struct io_kiocb *req)
1300 if ((req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) == REQ_F_LINK)
1301 req->flags |= REQ_F_FAIL_LINK;
1304 static void io_complete_rw_common(struct kiocb *kiocb, long res)
1306 struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
1308 if (kiocb->ki_flags & IOCB_WRITE)
1309 kiocb_end_write(req);
1311 if (res != req->result)
1312 req_set_fail_links(req);
1313 io_cqring_add_event(req, res);
1316 static void io_complete_rw(struct kiocb *kiocb, long res, long res2)
1318 struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
1320 io_complete_rw_common(kiocb, res);
1324 static struct io_kiocb *__io_complete_rw(struct kiocb *kiocb, long res)
1326 struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
1327 struct io_kiocb *nxt = NULL;
1329 io_complete_rw_common(kiocb, res);
1330 io_put_req_find_next(req, &nxt);
1335 static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2)
1337 struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
1339 if (kiocb->ki_flags & IOCB_WRITE)
1340 kiocb_end_write(req);
1342 if (res != req->result)
1343 req_set_fail_links(req);
1346 req->flags |= REQ_F_IOPOLL_COMPLETED;
1350 * After the iocb has been issued, it's safe to be found on the poll list.
1351 * Adding the kiocb to the list AFTER submission ensures that we don't
1352 * find it from a io_iopoll_getevents() thread before the issuer is done
1353 * accessing the kiocb cookie.
1355 static void io_iopoll_req_issued(struct io_kiocb *req)
1357 struct io_ring_ctx *ctx = req->ctx;
1360 * Track whether we have multiple files in our lists. This will impact
1361 * how we do polling eventually, not spinning if we're on potentially
1362 * different devices.
1364 if (list_empty(&ctx->poll_list)) {
1365 ctx->poll_multi_file = false;
1366 } else if (!ctx->poll_multi_file) {
1367 struct io_kiocb *list_req;
1369 list_req = list_first_entry(&ctx->poll_list, struct io_kiocb,
1371 if (list_req->rw.ki_filp != req->rw.ki_filp)
1372 ctx->poll_multi_file = true;
1376 * For fast devices, IO may have already completed. If it has, add
1377 * it to the front so we find it first.
1379 if (req->flags & REQ_F_IOPOLL_COMPLETED)
1380 list_add(&req->list, &ctx->poll_list);
1382 list_add_tail(&req->list, &ctx->poll_list);
1385 static void io_file_put(struct io_submit_state *state)
1388 int diff = state->has_refs - state->used_refs;
1391 fput_many(state->file, diff);
1397 * Get as many references to a file as we have IOs left in this submission,
1398 * assuming most submissions are for one file, or at least that each file
1399 * has more than one submission.
1401 static struct file *io_file_get(struct io_submit_state *state, int fd)
1407 if (state->fd == fd) {
1414 state->file = fget_many(fd, state->ios_left);
1419 state->has_refs = state->ios_left;
1420 state->used_refs = 1;
1426 * If we tracked the file through the SCM inflight mechanism, we could support
1427 * any file. For now, just ensure that anything potentially problematic is done
1430 static bool io_file_supports_async(struct file *file)
1432 umode_t mode = file_inode(file)->i_mode;
1434 if (S_ISBLK(mode) || S_ISCHR(mode) || S_ISSOCK(mode))
1436 if (S_ISREG(mode) && file->f_op != &io_uring_fops)
1442 static int io_prep_rw(struct io_kiocb *req, bool force_nonblock)
1444 const struct io_uring_sqe *sqe = req->sqe;
1445 struct io_ring_ctx *ctx = req->ctx;
1446 struct kiocb *kiocb = &req->rw;
1453 if (S_ISREG(file_inode(req->file)->i_mode))
1454 req->flags |= REQ_F_ISREG;
1456 kiocb->ki_pos = READ_ONCE(sqe->off);
1457 kiocb->ki_flags = iocb_flags(kiocb->ki_filp);
1458 kiocb->ki_hint = ki_hint_validate(file_write_hint(kiocb->ki_filp));
1460 ioprio = READ_ONCE(sqe->ioprio);
1462 ret = ioprio_check_cap(ioprio);
1466 kiocb->ki_ioprio = ioprio;
1468 kiocb->ki_ioprio = get_current_ioprio();
1470 ret = kiocb_set_rw_flags(kiocb, READ_ONCE(sqe->rw_flags));
1474 /* don't allow async punt if RWF_NOWAIT was requested */
1475 if ((kiocb->ki_flags & IOCB_NOWAIT) ||
1476 (req->file->f_flags & O_NONBLOCK))
1477 req->flags |= REQ_F_NOWAIT;
1480 kiocb->ki_flags |= IOCB_NOWAIT;
1482 if (ctx->flags & IORING_SETUP_IOPOLL) {
1483 if (!(kiocb->ki_flags & IOCB_DIRECT) ||
1484 !kiocb->ki_filp->f_op->iopoll)
1487 kiocb->ki_flags |= IOCB_HIPRI;
1488 kiocb->ki_complete = io_complete_rw_iopoll;
1491 if (kiocb->ki_flags & IOCB_HIPRI)
1493 kiocb->ki_complete = io_complete_rw;
1498 static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
1504 case -ERESTARTNOINTR:
1505 case -ERESTARTNOHAND:
1506 case -ERESTART_RESTARTBLOCK:
1508 * We can't just restart the syscall, since previously
1509 * submitted sqes may already be in progress. Just fail this
1515 kiocb->ki_complete(kiocb, ret, 0);
1519 static void kiocb_done(struct kiocb *kiocb, ssize_t ret, struct io_kiocb **nxt,
1522 if (in_async && ret >= 0 && kiocb->ki_complete == io_complete_rw)
1523 *nxt = __io_complete_rw(kiocb, ret);
1525 io_rw_done(kiocb, ret);
1528 static ssize_t io_import_fixed(struct io_ring_ctx *ctx, int rw,
1529 const struct io_uring_sqe *sqe,
1530 struct iov_iter *iter)
1532 size_t len = READ_ONCE(sqe->len);
1533 struct io_mapped_ubuf *imu;
1534 unsigned index, buf_index;
1538 /* attempt to use fixed buffers without having provided iovecs */
1539 if (unlikely(!ctx->user_bufs))
1542 buf_index = READ_ONCE(sqe->buf_index);
1543 if (unlikely(buf_index >= ctx->nr_user_bufs))
1546 index = array_index_nospec(buf_index, ctx->nr_user_bufs);
1547 imu = &ctx->user_bufs[index];
1548 buf_addr = READ_ONCE(sqe->addr);
1551 if (buf_addr + len < buf_addr)
1553 /* not inside the mapped region */
1554 if (buf_addr < imu->ubuf || buf_addr + len > imu->ubuf + imu->len)
1558 * May not be a start of buffer, set size appropriately
1559 * and advance us to the beginning.
1561 offset = buf_addr - imu->ubuf;
1562 iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len);
1566 * Don't use iov_iter_advance() here, as it's really slow for
1567 * using the latter parts of a big fixed buffer - it iterates
1568 * over each segment manually. We can cheat a bit here, because
1571 * 1) it's a BVEC iter, we set it up
1572 * 2) all bvecs are PAGE_SIZE in size, except potentially the
1573 * first and last bvec
1575 * So just find our index, and adjust the iterator afterwards.
1576 * If the offset is within the first bvec (or the whole first
1577 * bvec, just use iov_iter_advance(). This makes it easier
1578 * since we can just skip the first segment, which may not
1579 * be PAGE_SIZE aligned.
1581 const struct bio_vec *bvec = imu->bvec;
1583 if (offset <= bvec->bv_len) {
1584 iov_iter_advance(iter, offset);
1586 unsigned long seg_skip;
1588 /* skip first vec */
1589 offset -= bvec->bv_len;
1590 seg_skip = 1 + (offset >> PAGE_SHIFT);
1592 iter->bvec = bvec + seg_skip;
1593 iter->nr_segs -= seg_skip;
1594 iter->count -= bvec->bv_len + offset;
1595 iter->iov_offset = offset & ~PAGE_MASK;
1602 static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
1603 struct iovec **iovec, struct iov_iter *iter)
1605 const struct io_uring_sqe *sqe = req->sqe;
1606 void __user *buf = u64_to_user_ptr(READ_ONCE(sqe->addr));
1607 size_t sqe_len = READ_ONCE(sqe->len);
1611 * We're reading ->opcode for the second time, but the first read
1612 * doesn't care whether it's _FIXED or not, so it doesn't matter
1613 * whether ->opcode changes concurrently. The first read does care
1614 * about whether it is a READ or a WRITE, so we don't trust this read
1615 * for that purpose and instead let the caller pass in the read/write
1618 opcode = READ_ONCE(sqe->opcode);
1619 if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
1621 return io_import_fixed(req->ctx, rw, sqe, iter);
1625 struct io_async_rw *iorw = &req->io->rw;
1628 iov_iter_init(iter, rw, *iovec, iorw->nr_segs, iorw->size);
1629 if (iorw->iov == iorw->fast_iov)
1637 #ifdef CONFIG_COMPAT
1638 if (req->ctx->compat)
1639 return compat_import_iovec(rw, buf, sqe_len, UIO_FASTIOV,
1643 return import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter);
1647 * For files that don't have ->read_iter() and ->write_iter(), handle them
1648 * by looping over ->read() or ->write() manually.
1650 static ssize_t loop_rw_iter(int rw, struct file *file, struct kiocb *kiocb,
1651 struct iov_iter *iter)
1656 * Don't support polled IO through this interface, and we can't
1657 * support non-blocking either. For the latter, this just causes
1658 * the kiocb to be handled from an async context.
1660 if (kiocb->ki_flags & IOCB_HIPRI)
1662 if (kiocb->ki_flags & IOCB_NOWAIT)
1665 while (iov_iter_count(iter)) {
1669 if (!iov_iter_is_bvec(iter)) {
1670 iovec = iov_iter_iovec(iter);
1672 /* fixed buffers import bvec */
1673 iovec.iov_base = kmap(iter->bvec->bv_page)
1675 iovec.iov_len = min(iter->count,
1676 iter->bvec->bv_len - iter->iov_offset);
1680 nr = file->f_op->read(file, iovec.iov_base,
1681 iovec.iov_len, &kiocb->ki_pos);
1683 nr = file->f_op->write(file, iovec.iov_base,
1684 iovec.iov_len, &kiocb->ki_pos);
1687 if (iov_iter_is_bvec(iter))
1688 kunmap(iter->bvec->bv_page);
1696 if (nr != iovec.iov_len)
1698 iov_iter_advance(iter, nr);
1704 static void io_req_map_io(struct io_kiocb *req, ssize_t io_size,
1705 struct iovec *iovec, struct iovec *fast_iov,
1706 struct iov_iter *iter)
1708 req->io->rw.nr_segs = iter->nr_segs;
1709 req->io->rw.size = io_size;
1710 req->io->rw.iov = iovec;
1711 if (!req->io->rw.iov) {
1712 req->io->rw.iov = req->io->rw.fast_iov;
1713 memcpy(req->io->rw.iov, fast_iov,
1714 sizeof(struct iovec) * iter->nr_segs);
1718 static int io_setup_async_io(struct io_kiocb *req, ssize_t io_size,
1719 struct iovec *iovec, struct iovec *fast_iov,
1720 struct iov_iter *iter)
1722 req->io = kmalloc(sizeof(*req->io), GFP_KERNEL);
1724 io_req_map_io(req, io_size, iovec, fast_iov, iter);
1725 memcpy(&req->io->sqe, req->sqe, sizeof(req->io->sqe));
1726 req->sqe = &req->io->sqe;
1733 static int io_read_prep(struct io_kiocb *req, struct iovec **iovec,
1734 struct iov_iter *iter, bool force_nonblock)
1738 ret = io_prep_rw(req, force_nonblock);
1742 if (unlikely(!(req->file->f_mode & FMODE_READ)))
1745 return io_import_iovec(READ, req, iovec, iter);
1748 static int io_read(struct io_kiocb *req, struct io_kiocb **nxt,
1749 bool force_nonblock)
1751 struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
1752 struct kiocb *kiocb = &req->rw;
1753 struct iov_iter iter;
1756 ssize_t io_size, ret;
1759 ret = io_read_prep(req, &iovec, &iter, force_nonblock);
1763 ret = io_import_iovec(READ, req, &iovec, &iter);
1770 if (req->flags & REQ_F_LINK)
1771 req->result = io_size;
1774 * If the file doesn't support async, mark it as REQ_F_MUST_PUNT so
1775 * we know to async punt it even if it was opened O_NONBLOCK
1777 if (force_nonblock && !io_file_supports_async(file)) {
1778 req->flags |= REQ_F_MUST_PUNT;
1782 iov_count = iov_iter_count(&iter);
1783 ret = rw_verify_area(READ, file, &kiocb->ki_pos, iov_count);
1787 if (file->f_op->read_iter)
1788 ret2 = call_read_iter(file, kiocb, &iter);
1790 ret2 = loop_rw_iter(READ, file, kiocb, &iter);
1793 * In case of a short read, punt to async. This can happen
1794 * if we have data partially cached. Alternatively we can
1795 * return the short read, in which case the application will
1796 * need to issue another SQE and wait for it. That SQE will
1797 * need async punt anyway, so it's more efficient to do it
1800 if (force_nonblock && !(req->flags & REQ_F_NOWAIT) &&
1801 (req->flags & REQ_F_ISREG) &&
1802 ret2 > 0 && ret2 < io_size)
1804 /* Catch -EAGAIN return for forced non-blocking submission */
1805 if (!force_nonblock || ret2 != -EAGAIN) {
1806 kiocb_done(kiocb, ret2, nxt, req->in_async);
1809 ret = io_setup_async_io(req, io_size, iovec,
1810 inline_vecs, &iter);
1821 static int io_write_prep(struct io_kiocb *req, struct iovec **iovec,
1822 struct iov_iter *iter, bool force_nonblock)
1826 ret = io_prep_rw(req, force_nonblock);
1830 if (unlikely(!(req->file->f_mode & FMODE_WRITE)))
1833 return io_import_iovec(WRITE, req, iovec, iter);
1836 static int io_write(struct io_kiocb *req, struct io_kiocb **nxt,
1837 bool force_nonblock)
1839 struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
1840 struct kiocb *kiocb = &req->rw;
1841 struct iov_iter iter;
1844 ssize_t ret, io_size;
1847 ret = io_write_prep(req, &iovec, &iter, force_nonblock);
1851 ret = io_import_iovec(WRITE, req, &iovec, &iter);
1856 file = kiocb->ki_filp;
1858 if (req->flags & REQ_F_LINK)
1859 req->result = io_size;
1862 * If the file doesn't support async, mark it as REQ_F_MUST_PUNT so
1863 * we know to async punt it even if it was opened O_NONBLOCK
1865 if (force_nonblock && !io_file_supports_async(req->file)) {
1866 req->flags |= REQ_F_MUST_PUNT;
1870 /* file path doesn't support NOWAIT for non-direct_IO */
1871 if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT) &&
1872 (req->flags & REQ_F_ISREG))
1875 iov_count = iov_iter_count(&iter);
1876 ret = rw_verify_area(WRITE, file, &kiocb->ki_pos, iov_count);
1881 * Open-code file_start_write here to grab freeze protection,
1882 * which will be released by another thread in
1883 * io_complete_rw(). Fool lockdep by telling it the lock got
1884 * released so that it doesn't complain about the held lock when
1885 * we return to userspace.
1887 if (req->flags & REQ_F_ISREG) {
1888 __sb_start_write(file_inode(file)->i_sb,
1889 SB_FREEZE_WRITE, true);
1890 __sb_writers_release(file_inode(file)->i_sb,
1893 kiocb->ki_flags |= IOCB_WRITE;
1895 if (file->f_op->write_iter)
1896 ret2 = call_write_iter(file, kiocb, &iter);
1898 ret2 = loop_rw_iter(WRITE, file, kiocb, &iter);
1899 if (!force_nonblock || ret2 != -EAGAIN) {
1900 kiocb_done(kiocb, ret2, nxt, req->in_async);
1903 ret = io_setup_async_io(req, io_size, iovec,
1904 inline_vecs, &iter);
1916 * IORING_OP_NOP just posts a completion event, nothing else.
1918 static int io_nop(struct io_kiocb *req)
1920 struct io_ring_ctx *ctx = req->ctx;
1922 if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
1925 io_cqring_add_event(req, 0);
1930 static int io_prep_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1932 struct io_ring_ctx *ctx = req->ctx;
1937 if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
1939 if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index))
1945 static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe,
1946 struct io_kiocb **nxt, bool force_nonblock)
1948 loff_t sqe_off = READ_ONCE(sqe->off);
1949 loff_t sqe_len = READ_ONCE(sqe->len);
1950 loff_t end = sqe_off + sqe_len;
1951 unsigned fsync_flags;
1954 fsync_flags = READ_ONCE(sqe->fsync_flags);
1955 if (unlikely(fsync_flags & ~IORING_FSYNC_DATASYNC))
1958 ret = io_prep_fsync(req, sqe);
1962 /* fsync always requires a blocking context */
1966 ret = vfs_fsync_range(req->rw.ki_filp, sqe_off,
1967 end > 0 ? end : LLONG_MAX,
1968 fsync_flags & IORING_FSYNC_DATASYNC);
1971 req_set_fail_links(req);
1972 io_cqring_add_event(req, ret);
1973 io_put_req_find_next(req, nxt);
1977 static int io_prep_sfr(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1979 struct io_ring_ctx *ctx = req->ctx;
1985 if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
1987 if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index))
1993 static int io_sync_file_range(struct io_kiocb *req,
1994 const struct io_uring_sqe *sqe,
1995 struct io_kiocb **nxt,
1996 bool force_nonblock)
2003 ret = io_prep_sfr(req, sqe);
2007 /* sync_file_range always requires a blocking context */
2011 sqe_off = READ_ONCE(sqe->off);
2012 sqe_len = READ_ONCE(sqe->len);
2013 flags = READ_ONCE(sqe->sync_range_flags);
2015 ret = sync_file_range(req->rw.ki_filp, sqe_off, sqe_len, flags);
2018 req_set_fail_links(req);
2019 io_cqring_add_event(req, ret);
2020 io_put_req_find_next(req, nxt);
2024 static int io_sendmsg_prep(struct io_kiocb *req, struct io_async_ctx *io)
2026 #if defined(CONFIG_NET)
2027 const struct io_uring_sqe *sqe = req->sqe;
2028 struct user_msghdr __user *msg;
2031 flags = READ_ONCE(sqe->msg_flags);
2032 msg = (struct user_msghdr __user *)(unsigned long) READ_ONCE(sqe->addr);
2033 io->msg.iov = io->msg.fast_iov;
2034 return sendmsg_copy_msghdr(&io->msg.msg, msg, flags, &io->msg.iov);
2040 static int io_sendmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe,
2041 struct io_kiocb **nxt, bool force_nonblock)
2043 #if defined(CONFIG_NET)
2044 struct socket *sock;
2047 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
2050 sock = sock_from_file(req->file, &ret);
2052 struct io_async_ctx io, *copy;
2053 struct sockaddr_storage addr;
2054 struct msghdr *kmsg;
2057 flags = READ_ONCE(sqe->msg_flags);
2058 if (flags & MSG_DONTWAIT)
2059 req->flags |= REQ_F_NOWAIT;
2060 else if (force_nonblock)
2061 flags |= MSG_DONTWAIT;
2064 kmsg = &req->io->msg.msg;
2065 kmsg->msg_name = &addr;
2068 kmsg->msg_name = &addr;
2069 ret = io_sendmsg_prep(req, &io);
2074 ret = __sys_sendmsg_sock(sock, kmsg, flags);
2075 if (force_nonblock && ret == -EAGAIN) {
2076 copy = kmalloc(sizeof(*copy), GFP_KERNEL);
2081 memcpy(©->msg, &io.msg, sizeof(copy->msg));
2083 memcpy(&req->io->sqe, req->sqe, sizeof(*req->sqe));
2084 req->sqe = &req->io->sqe;
2087 if (ret == -ERESTARTSYS)
2092 io_cqring_add_event(req, ret);
2094 req_set_fail_links(req);
2095 io_put_req_find_next(req, nxt);
2102 static int io_recvmsg_prep(struct io_kiocb *req, struct io_async_ctx *io)
2104 #if defined(CONFIG_NET)
2105 const struct io_uring_sqe *sqe = req->sqe;
2106 struct user_msghdr __user *msg;
2109 flags = READ_ONCE(sqe->msg_flags);
2110 msg = (struct user_msghdr __user *)(unsigned long) READ_ONCE(sqe->addr);
2111 io->msg.iov = io->msg.fast_iov;
2112 return recvmsg_copy_msghdr(&io->msg.msg, msg, flags, &io->msg.uaddr,
2119 static int io_recvmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe,
2120 struct io_kiocb **nxt, bool force_nonblock)
2122 #if defined(CONFIG_NET)
2123 struct socket *sock;
2126 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
2129 sock = sock_from_file(req->file, &ret);
2131 struct user_msghdr __user *msg;
2132 struct io_async_ctx io, *copy;
2133 struct sockaddr_storage addr;
2134 struct msghdr *kmsg;
2137 flags = READ_ONCE(sqe->msg_flags);
2138 if (flags & MSG_DONTWAIT)
2139 req->flags |= REQ_F_NOWAIT;
2140 else if (force_nonblock)
2141 flags |= MSG_DONTWAIT;
2143 msg = (struct user_msghdr __user *) (unsigned long)
2144 READ_ONCE(sqe->addr);
2146 kmsg = &req->io->msg.msg;
2147 kmsg->msg_name = &addr;
2150 kmsg->msg_name = &addr;
2151 ret = io_recvmsg_prep(req, &io);
2156 ret = __sys_recvmsg_sock(sock, kmsg, msg, io.msg.uaddr, flags);
2157 if (force_nonblock && ret == -EAGAIN) {
2158 copy = kmalloc(sizeof(*copy), GFP_KERNEL);
2163 memcpy(copy, &io, sizeof(*copy));
2165 memcpy(&req->io->sqe, req->sqe, sizeof(*req->sqe));
2166 req->sqe = &req->io->sqe;
2169 if (ret == -ERESTARTSYS)
2174 io_cqring_add_event(req, ret);
2176 req_set_fail_links(req);
2177 io_put_req_find_next(req, nxt);
2184 static int io_accept(struct io_kiocb *req, const struct io_uring_sqe *sqe,
2185 struct io_kiocb **nxt, bool force_nonblock)
2187 #if defined(CONFIG_NET)
2188 struct sockaddr __user *addr;
2189 int __user *addr_len;
2190 unsigned file_flags;
2193 if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
2195 if (sqe->ioprio || sqe->len || sqe->buf_index)
2198 addr = (struct sockaddr __user *) (unsigned long) READ_ONCE(sqe->addr);
2199 addr_len = (int __user *) (unsigned long) READ_ONCE(sqe->addr2);
2200 flags = READ_ONCE(sqe->accept_flags);
2201 file_flags = force_nonblock ? O_NONBLOCK : 0;
2203 ret = __sys_accept4_file(req->file, file_flags, addr, addr_len, flags);
2204 if (ret == -EAGAIN && force_nonblock) {
2205 req->work.flags |= IO_WQ_WORK_NEEDS_FILES;
2208 if (ret == -ERESTARTSYS)
2211 req_set_fail_links(req);
2212 io_cqring_add_event(req, ret);
2213 io_put_req_find_next(req, nxt);
2220 static int io_connect_prep(struct io_kiocb *req, struct io_async_ctx *io)
2222 #if defined(CONFIG_NET)
2223 const struct io_uring_sqe *sqe = req->sqe;
2224 struct sockaddr __user *addr;
2227 addr = (struct sockaddr __user *) (unsigned long) READ_ONCE(sqe->addr);
2228 addr_len = READ_ONCE(sqe->addr2);
2229 return move_addr_to_kernel(addr, addr_len, &io->connect.address);
2235 static int io_connect(struct io_kiocb *req, const struct io_uring_sqe *sqe,
2236 struct io_kiocb **nxt, bool force_nonblock)
2238 #if defined(CONFIG_NET)
2239 struct io_async_ctx __io, *io;
2240 unsigned file_flags;
2243 if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
2245 if (sqe->ioprio || sqe->len || sqe->buf_index || sqe->rw_flags)
2248 addr_len = READ_ONCE(sqe->addr2);
2249 file_flags = force_nonblock ? O_NONBLOCK : 0;
2254 ret = io_connect_prep(req, &__io);
2260 ret = __sys_connect_file(req->file, &io->connect.address, addr_len,
2262 if ((ret == -EAGAIN || ret == -EINPROGRESS) && force_nonblock) {
2263 io = kmalloc(sizeof(*io), GFP_KERNEL);
2268 memcpy(&io->connect, &__io.connect, sizeof(io->connect));
2270 memcpy(&io->sqe, req->sqe, sizeof(*req->sqe));
2271 req->sqe = &io->sqe;
2274 if (ret == -ERESTARTSYS)
2278 req_set_fail_links(req);
2279 io_cqring_add_event(req, ret);
2280 io_put_req_find_next(req, nxt);
2287 static void io_poll_remove_one(struct io_kiocb *req)
2289 struct io_poll_iocb *poll = &req->poll;
2291 spin_lock(&poll->head->lock);
2292 WRITE_ONCE(poll->canceled, true);
2293 if (!list_empty(&poll->wait.entry)) {
2294 list_del_init(&poll->wait.entry);
2295 io_queue_async_work(req);
2297 spin_unlock(&poll->head->lock);
2298 hash_del(&req->hash_node);
2301 static void io_poll_remove_all(struct io_ring_ctx *ctx)
2303 struct hlist_node *tmp;
2304 struct io_kiocb *req;
2307 spin_lock_irq(&ctx->completion_lock);
2308 for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
2309 struct hlist_head *list;
2311 list = &ctx->cancel_hash[i];
2312 hlist_for_each_entry_safe(req, tmp, list, hash_node)
2313 io_poll_remove_one(req);
2315 spin_unlock_irq(&ctx->completion_lock);
2318 static int io_poll_cancel(struct io_ring_ctx *ctx, __u64 sqe_addr)
2320 struct hlist_head *list;
2321 struct io_kiocb *req;
2323 list = &ctx->cancel_hash[hash_long(sqe_addr, ctx->cancel_hash_bits)];
2324 hlist_for_each_entry(req, list, hash_node) {
2325 if (sqe_addr == req->user_data) {
2326 io_poll_remove_one(req);
2335 * Find a running poll command that matches one specified in sqe->addr,
2336 * and remove it if found.
2338 static int io_poll_remove(struct io_kiocb *req, const struct io_uring_sqe *sqe)
2340 struct io_ring_ctx *ctx = req->ctx;
2343 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
2345 if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index ||
2349 spin_lock_irq(&ctx->completion_lock);
2350 ret = io_poll_cancel(ctx, READ_ONCE(sqe->addr));
2351 spin_unlock_irq(&ctx->completion_lock);
2353 io_cqring_add_event(req, ret);
2355 req_set_fail_links(req);
2360 static void io_poll_complete(struct io_kiocb *req, __poll_t mask, int error)
2362 struct io_ring_ctx *ctx = req->ctx;
2364 req->poll.done = true;
2366 io_cqring_fill_event(req, error);
2368 io_cqring_fill_event(req, mangle_poll(mask));
2369 io_commit_cqring(ctx);
2372 static void io_poll_complete_work(struct io_wq_work **workptr)
2374 struct io_wq_work *work = *workptr;
2375 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
2376 struct io_poll_iocb *poll = &req->poll;
2377 struct poll_table_struct pt = { ._key = poll->events };
2378 struct io_ring_ctx *ctx = req->ctx;
2379 struct io_kiocb *nxt = NULL;
2383 if (work->flags & IO_WQ_WORK_CANCEL) {
2384 WRITE_ONCE(poll->canceled, true);
2386 } else if (READ_ONCE(poll->canceled)) {
2390 if (ret != -ECANCELED)
2391 mask = vfs_poll(poll->file, &pt) & poll->events;
2394 * Note that ->ki_cancel callers also delete iocb from active_reqs after
2395 * calling ->ki_cancel. We need the ctx_lock roundtrip here to
2396 * synchronize with them. In the cancellation case the list_del_init
2397 * itself is not actually needed, but harmless so we keep it in to
2398 * avoid further branches in the fast path.
2400 spin_lock_irq(&ctx->completion_lock);
2401 if (!mask && ret != -ECANCELED) {
2402 add_wait_queue(poll->head, &poll->wait);
2403 spin_unlock_irq(&ctx->completion_lock);
2406 hash_del(&req->hash_node);
2407 io_poll_complete(req, mask, ret);
2408 spin_unlock_irq(&ctx->completion_lock);
2410 io_cqring_ev_posted(ctx);
2413 req_set_fail_links(req);
2414 io_put_req_find_next(req, &nxt);
2416 *workptr = &nxt->work;
2419 static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
2422 struct io_poll_iocb *poll = wait->private;
2423 struct io_kiocb *req = container_of(poll, struct io_kiocb, poll);
2424 struct io_ring_ctx *ctx = req->ctx;
2425 __poll_t mask = key_to_poll(key);
2426 unsigned long flags;
2428 /* for instances that support it check for an event match first: */
2429 if (mask && !(mask & poll->events))
2432 list_del_init(&poll->wait.entry);
2435 * Run completion inline if we can. We're using trylock here because
2436 * we are violating the completion_lock -> poll wq lock ordering.
2437 * If we have a link timeout we're going to need the completion_lock
2438 * for finalizing the request, mark us as having grabbed that already.
2440 if (mask && spin_trylock_irqsave(&ctx->completion_lock, flags)) {
2441 hash_del(&req->hash_node);
2442 io_poll_complete(req, mask, 0);
2443 req->flags |= REQ_F_COMP_LOCKED;
2445 spin_unlock_irqrestore(&ctx->completion_lock, flags);
2447 io_cqring_ev_posted(ctx);
2449 io_queue_async_work(req);
2455 struct io_poll_table {
2456 struct poll_table_struct pt;
2457 struct io_kiocb *req;
2461 static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head,
2462 struct poll_table_struct *p)
2464 struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
2466 if (unlikely(pt->req->poll.head)) {
2467 pt->error = -EINVAL;
2472 pt->req->poll.head = head;
2473 add_wait_queue(head, &pt->req->poll.wait);
2476 static void io_poll_req_insert(struct io_kiocb *req)
2478 struct io_ring_ctx *ctx = req->ctx;
2479 struct hlist_head *list;
2481 list = &ctx->cancel_hash[hash_long(req->user_data, ctx->cancel_hash_bits)];
2482 hlist_add_head(&req->hash_node, list);
2485 static int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe,
2486 struct io_kiocb **nxt)
2488 struct io_poll_iocb *poll = &req->poll;
2489 struct io_ring_ctx *ctx = req->ctx;
2490 struct io_poll_table ipt;
2491 bool cancel = false;
2495 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
2497 if (sqe->addr || sqe->ioprio || sqe->off || sqe->len || sqe->buf_index)
2503 INIT_IO_WORK(&req->work, io_poll_complete_work);
2504 events = READ_ONCE(sqe->poll_events);
2505 poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP;
2506 INIT_HLIST_NODE(&req->hash_node);
2510 poll->canceled = false;
2512 ipt.pt._qproc = io_poll_queue_proc;
2513 ipt.pt._key = poll->events;
2515 ipt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */
2517 /* initialized the list so that we can do list_empty checks */
2518 INIT_LIST_HEAD(&poll->wait.entry);
2519 init_waitqueue_func_entry(&poll->wait, io_poll_wake);
2520 poll->wait.private = poll;
2522 INIT_LIST_HEAD(&req->list);
2524 mask = vfs_poll(poll->file, &ipt.pt) & poll->events;
2526 spin_lock_irq(&ctx->completion_lock);
2527 if (likely(poll->head)) {
2528 spin_lock(&poll->head->lock);
2529 if (unlikely(list_empty(&poll->wait.entry))) {
2535 if (mask || ipt.error)
2536 list_del_init(&poll->wait.entry);
2538 WRITE_ONCE(poll->canceled, true);
2539 else if (!poll->done) /* actually waiting for an event */
2540 io_poll_req_insert(req);
2541 spin_unlock(&poll->head->lock);
2543 if (mask) { /* no async, we'd stolen it */
2545 io_poll_complete(req, mask, 0);
2547 spin_unlock_irq(&ctx->completion_lock);
2550 io_cqring_ev_posted(ctx);
2551 io_put_req_find_next(req, nxt);
2556 static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
2558 struct io_timeout_data *data = container_of(timer,
2559 struct io_timeout_data, timer);
2560 struct io_kiocb *req = data->req;
2561 struct io_ring_ctx *ctx = req->ctx;
2562 unsigned long flags;
2564 atomic_inc(&ctx->cq_timeouts);
2566 spin_lock_irqsave(&ctx->completion_lock, flags);
2568 * We could be racing with timeout deletion. If the list is empty,
2569 * then timeout lookup already found it and will be handling it.
2571 if (!list_empty(&req->list)) {
2572 struct io_kiocb *prev;
2575 * Adjust the reqs sequence before the current one because it
2576 * will consume a slot in the cq_ring and the the cq_tail
2577 * pointer will be increased, otherwise other timeout reqs may
2578 * return in advance without waiting for enough wait_nr.
2581 list_for_each_entry_continue_reverse(prev, &ctx->timeout_list, list)
2583 list_del_init(&req->list);
2586 io_cqring_fill_event(req, -ETIME);
2587 io_commit_cqring(ctx);
2588 spin_unlock_irqrestore(&ctx->completion_lock, flags);
2590 io_cqring_ev_posted(ctx);
2591 req_set_fail_links(req);
2593 return HRTIMER_NORESTART;
2596 static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data)
2598 struct io_kiocb *req;
2601 list_for_each_entry(req, &ctx->timeout_list, list) {
2602 if (user_data == req->user_data) {
2603 list_del_init(&req->list);
2612 ret = hrtimer_try_to_cancel(&req->io->timeout.timer);
2616 req_set_fail_links(req);
2617 io_cqring_fill_event(req, -ECANCELED);
2623 * Remove or update an existing timeout command
2625 static int io_timeout_remove(struct io_kiocb *req,
2626 const struct io_uring_sqe *sqe)
2628 struct io_ring_ctx *ctx = req->ctx;
2632 if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
2634 if (sqe->flags || sqe->ioprio || sqe->buf_index || sqe->len)
2636 flags = READ_ONCE(sqe->timeout_flags);
2640 spin_lock_irq(&ctx->completion_lock);
2641 ret = io_timeout_cancel(ctx, READ_ONCE(sqe->addr));
2643 io_cqring_fill_event(req, ret);
2644 io_commit_cqring(ctx);
2645 spin_unlock_irq(&ctx->completion_lock);
2646 io_cqring_ev_posted(ctx);
2648 req_set_fail_links(req);
2653 static int io_timeout_prep(struct io_kiocb *req, struct io_async_ctx *io,
2654 bool is_timeout_link)
2656 const struct io_uring_sqe *sqe = req->sqe;
2657 struct io_timeout_data *data;
2660 if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
2662 if (sqe->ioprio || sqe->buf_index || sqe->len != 1)
2664 if (sqe->off && is_timeout_link)
2666 flags = READ_ONCE(sqe->timeout_flags);
2667 if (flags & ~IORING_TIMEOUT_ABS)
2670 data = &io->timeout;
2672 req->flags |= REQ_F_TIMEOUT;
2674 if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr)))
2677 if (flags & IORING_TIMEOUT_ABS)
2678 data->mode = HRTIMER_MODE_ABS;
2680 data->mode = HRTIMER_MODE_REL;
2682 hrtimer_init(&data->timer, CLOCK_MONOTONIC, data->mode);
2687 static int io_timeout(struct io_kiocb *req, const struct io_uring_sqe *sqe)
2690 struct io_ring_ctx *ctx = req->ctx;
2691 struct io_timeout_data *data;
2692 struct io_async_ctx *io;
2693 struct list_head *entry;
2700 io = kmalloc(sizeof(*io), GFP_KERNEL);
2703 ret = io_timeout_prep(req, io, false);
2709 data = &req->io->timeout;
2712 * sqe->off holds how many events that need to occur for this
2713 * timeout event to be satisfied. If it isn't set, then this is
2714 * a pure timeout request, sequence isn't used.
2716 count = READ_ONCE(sqe->off);
2718 req->flags |= REQ_F_TIMEOUT_NOSEQ;
2719 spin_lock_irq(&ctx->completion_lock);
2720 entry = ctx->timeout_list.prev;
2724 req->sequence = ctx->cached_sq_head + count - 1;
2725 data->seq_offset = count;
2728 * Insertion sort, ensuring the first entry in the list is always
2729 * the one we need first.
2731 spin_lock_irq(&ctx->completion_lock);
2732 list_for_each_prev(entry, &ctx->timeout_list) {
2733 struct io_kiocb *nxt = list_entry(entry, struct io_kiocb, list);
2734 unsigned nxt_sq_head;
2735 long long tmp, tmp_nxt;
2736 u32 nxt_offset = nxt->io->timeout.seq_offset;
2738 if (nxt->flags & REQ_F_TIMEOUT_NOSEQ)
2742 * Since cached_sq_head + count - 1 can overflow, use type long
2745 tmp = (long long)ctx->cached_sq_head + count - 1;
2746 nxt_sq_head = nxt->sequence - nxt_offset + 1;
2747 tmp_nxt = (long long)nxt_sq_head + nxt_offset - 1;
2750 * cached_sq_head may overflow, and it will never overflow twice
2751 * once there is some timeout req still be valid.
2753 if (ctx->cached_sq_head < nxt_sq_head)
2760 * Sequence of reqs after the insert one and itself should
2761 * be adjusted because each timeout req consumes a slot.
2766 req->sequence -= span;
2768 list_add(&req->list, entry);
2769 data->timer.function = io_timeout_fn;
2770 hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode);
2771 spin_unlock_irq(&ctx->completion_lock);
2775 static bool io_cancel_cb(struct io_wq_work *work, void *data)
2777 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
2779 return req->user_data == (unsigned long) data;
2782 static int io_async_cancel_one(struct io_ring_ctx *ctx, void *sqe_addr)
2784 enum io_wq_cancel cancel_ret;
2787 cancel_ret = io_wq_cancel_cb(ctx->io_wq, io_cancel_cb, sqe_addr);
2788 switch (cancel_ret) {
2789 case IO_WQ_CANCEL_OK:
2792 case IO_WQ_CANCEL_RUNNING:
2795 case IO_WQ_CANCEL_NOTFOUND:
2803 static void io_async_find_and_cancel(struct io_ring_ctx *ctx,
2804 struct io_kiocb *req, __u64 sqe_addr,
2805 struct io_kiocb **nxt, int success_ret)
2807 unsigned long flags;
2810 ret = io_async_cancel_one(ctx, (void *) (unsigned long) sqe_addr);
2811 if (ret != -ENOENT) {
2812 spin_lock_irqsave(&ctx->completion_lock, flags);
2816 spin_lock_irqsave(&ctx->completion_lock, flags);
2817 ret = io_timeout_cancel(ctx, sqe_addr);
2820 ret = io_poll_cancel(ctx, sqe_addr);
2824 io_cqring_fill_event(req, ret);
2825 io_commit_cqring(ctx);
2826 spin_unlock_irqrestore(&ctx->completion_lock, flags);
2827 io_cqring_ev_posted(ctx);
2830 req_set_fail_links(req);
2831 io_put_req_find_next(req, nxt);
2834 static int io_async_cancel(struct io_kiocb *req, const struct io_uring_sqe *sqe,
2835 struct io_kiocb **nxt)
2837 struct io_ring_ctx *ctx = req->ctx;
2839 if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
2841 if (sqe->flags || sqe->ioprio || sqe->off || sqe->len ||
2845 io_async_find_and_cancel(ctx, req, READ_ONCE(sqe->addr), nxt, 0);
2849 static int io_req_defer_prep(struct io_kiocb *req, struct io_async_ctx *io)
2851 struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
2852 struct iov_iter iter;
2855 memcpy(&io->sqe, req->sqe, sizeof(io->sqe));
2856 req->sqe = &io->sqe;
2858 switch (io->sqe.opcode) {
2859 case IORING_OP_READV:
2860 case IORING_OP_READ_FIXED:
2861 ret = io_read_prep(req, &iovec, &iter, true);
2863 case IORING_OP_WRITEV:
2864 case IORING_OP_WRITE_FIXED:
2865 ret = io_write_prep(req, &iovec, &iter, true);
2867 case IORING_OP_SENDMSG:
2868 ret = io_sendmsg_prep(req, io);
2870 case IORING_OP_RECVMSG:
2871 ret = io_recvmsg_prep(req, io);
2873 case IORING_OP_CONNECT:
2874 ret = io_connect_prep(req, io);
2876 case IORING_OP_TIMEOUT:
2877 return io_timeout_prep(req, io, false);
2878 case IORING_OP_LINK_TIMEOUT:
2879 return io_timeout_prep(req, io, true);
2889 io_req_map_io(req, ret, iovec, inline_vecs, &iter);
2893 static int io_req_defer(struct io_kiocb *req)
2895 struct io_ring_ctx *ctx = req->ctx;
2896 struct io_async_ctx *io;
2899 /* Still need defer if there is pending req in defer list. */
2900 if (!req_need_defer(req) && list_empty(&ctx->defer_list))
2903 io = kmalloc(sizeof(*io), GFP_KERNEL);
2907 ret = io_req_defer_prep(req, io);
2913 spin_lock_irq(&ctx->completion_lock);
2914 if (!req_need_defer(req) && list_empty(&ctx->defer_list)) {
2915 spin_unlock_irq(&ctx->completion_lock);
2919 trace_io_uring_defer(ctx, req, req->user_data);
2920 list_add_tail(&req->list, &ctx->defer_list);
2921 spin_unlock_irq(&ctx->completion_lock);
2922 return -EIOCBQUEUED;
2925 __attribute__((nonnull))
2926 static int io_issue_sqe(struct io_kiocb *req, struct io_kiocb **nxt,
2927 bool force_nonblock)
2930 struct io_ring_ctx *ctx = req->ctx;
2932 opcode = READ_ONCE(req->sqe->opcode);
2937 case IORING_OP_READV:
2938 if (unlikely(req->sqe->buf_index))
2940 ret = io_read(req, nxt, force_nonblock);
2942 case IORING_OP_WRITEV:
2943 if (unlikely(req->sqe->buf_index))
2945 ret = io_write(req, nxt, force_nonblock);
2947 case IORING_OP_READ_FIXED:
2948 ret = io_read(req, nxt, force_nonblock);
2950 case IORING_OP_WRITE_FIXED:
2951 ret = io_write(req, nxt, force_nonblock);
2953 case IORING_OP_FSYNC:
2954 ret = io_fsync(req, req->sqe, nxt, force_nonblock);
2956 case IORING_OP_POLL_ADD:
2957 ret = io_poll_add(req, req->sqe, nxt);
2959 case IORING_OP_POLL_REMOVE:
2960 ret = io_poll_remove(req, req->sqe);
2962 case IORING_OP_SYNC_FILE_RANGE:
2963 ret = io_sync_file_range(req, req->sqe, nxt, force_nonblock);
2965 case IORING_OP_SENDMSG:
2966 ret = io_sendmsg(req, req->sqe, nxt, force_nonblock);
2968 case IORING_OP_RECVMSG:
2969 ret = io_recvmsg(req, req->sqe, nxt, force_nonblock);
2971 case IORING_OP_TIMEOUT:
2972 ret = io_timeout(req, req->sqe);
2974 case IORING_OP_TIMEOUT_REMOVE:
2975 ret = io_timeout_remove(req, req->sqe);
2977 case IORING_OP_ACCEPT:
2978 ret = io_accept(req, req->sqe, nxt, force_nonblock);
2980 case IORING_OP_CONNECT:
2981 ret = io_connect(req, req->sqe, nxt, force_nonblock);
2983 case IORING_OP_ASYNC_CANCEL:
2984 ret = io_async_cancel(req, req->sqe, nxt);
2994 if (ctx->flags & IORING_SETUP_IOPOLL) {
2995 if (req->result == -EAGAIN)
2998 io_iopoll_req_issued(req);
3004 static void io_link_work_cb(struct io_wq_work **workptr)
3006 struct io_wq_work *work = *workptr;
3007 struct io_kiocb *link = work->data;
3009 io_queue_linked_timeout(link);
3010 work->func = io_wq_submit_work;
3013 static void io_wq_submit_work(struct io_wq_work **workptr)
3015 struct io_wq_work *work = *workptr;
3016 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
3017 struct io_kiocb *nxt = NULL;
3020 /* Ensure we clear previously set non-block flag */
3021 req->rw.ki_flags &= ~IOCB_NOWAIT;
3023 if (work->flags & IO_WQ_WORK_CANCEL)
3027 req->has_user = (work->flags & IO_WQ_WORK_HAS_MM) != 0;
3028 req->in_async = true;
3030 ret = io_issue_sqe(req, &nxt, false);
3032 * We can get EAGAIN for polled IO even though we're
3033 * forcing a sync submission from here, since we can't
3034 * wait for request slots on the block side.
3042 /* drop submission reference */
3046 req_set_fail_links(req);
3047 io_cqring_add_event(req, ret);
3051 /* if a dependent link is ready, pass it back */
3053 struct io_kiocb *link;
3055 io_prep_async_work(nxt, &link);
3056 *workptr = &nxt->work;
3058 nxt->work.flags |= IO_WQ_WORK_CB;
3059 nxt->work.func = io_link_work_cb;
3060 nxt->work.data = link;
3065 static bool io_req_op_valid(int op)
3067 return op >= IORING_OP_NOP && op < IORING_OP_LAST;
3070 static int io_op_needs_file(const struct io_uring_sqe *sqe)
3072 int op = READ_ONCE(sqe->opcode);
3076 case IORING_OP_POLL_REMOVE:
3077 case IORING_OP_TIMEOUT:
3078 case IORING_OP_TIMEOUT_REMOVE:
3079 case IORING_OP_ASYNC_CANCEL:
3080 case IORING_OP_LINK_TIMEOUT:
3083 if (io_req_op_valid(op))
3089 static inline struct file *io_file_from_index(struct io_ring_ctx *ctx,
3092 struct fixed_file_table *table;
3094 table = &ctx->file_table[index >> IORING_FILE_TABLE_SHIFT];
3095 return table->files[index & IORING_FILE_TABLE_MASK];
3098 static int io_req_set_file(struct io_submit_state *state, struct io_kiocb *req)
3100 struct io_ring_ctx *ctx = req->ctx;
3104 flags = READ_ONCE(req->sqe->flags);
3105 fd = READ_ONCE(req->sqe->fd);
3107 if (flags & IOSQE_IO_DRAIN)
3108 req->flags |= REQ_F_IO_DRAIN;
3110 ret = io_op_needs_file(req->sqe);
3114 if (flags & IOSQE_FIXED_FILE) {
3115 if (unlikely(!ctx->file_table ||
3116 (unsigned) fd >= ctx->nr_user_files))
3118 fd = array_index_nospec(fd, ctx->nr_user_files);
3119 req->file = io_file_from_index(ctx, fd);
3122 req->flags |= REQ_F_FIXED_FILE;
3124 if (req->needs_fixed_file)
3126 trace_io_uring_file_get(ctx, fd);
3127 req->file = io_file_get(state, fd);
3128 if (unlikely(!req->file))
3135 static int io_grab_files(struct io_kiocb *req)
3138 struct io_ring_ctx *ctx = req->ctx;
3141 spin_lock_irq(&ctx->inflight_lock);
3143 * We use the f_ops->flush() handler to ensure that we can flush
3144 * out work accessing these files if the fd is closed. Check if
3145 * the fd has changed since we started down this path, and disallow
3146 * this operation if it has.
3148 if (fcheck(req->ring_fd) == req->ring_file) {
3149 list_add(&req->inflight_entry, &ctx->inflight_list);
3150 req->flags |= REQ_F_INFLIGHT;
3151 req->work.files = current->files;
3154 spin_unlock_irq(&ctx->inflight_lock);
3160 static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer)
3162 struct io_timeout_data *data = container_of(timer,
3163 struct io_timeout_data, timer);
3164 struct io_kiocb *req = data->req;
3165 struct io_ring_ctx *ctx = req->ctx;
3166 struct io_kiocb *prev = NULL;
3167 unsigned long flags;
3169 spin_lock_irqsave(&ctx->completion_lock, flags);
3172 * We don't expect the list to be empty, that will only happen if we
3173 * race with the completion of the linked work.
3175 if (!list_empty(&req->link_list)) {
3176 prev = list_entry(req->link_list.prev, struct io_kiocb,
3178 if (refcount_inc_not_zero(&prev->refs)) {
3179 list_del_init(&req->link_list);
3180 prev->flags &= ~REQ_F_LINK_TIMEOUT;
3185 spin_unlock_irqrestore(&ctx->completion_lock, flags);
3188 req_set_fail_links(prev);
3189 io_async_find_and_cancel(ctx, req, prev->user_data, NULL,
3193 io_cqring_add_event(req, -ETIME);
3196 return HRTIMER_NORESTART;
3199 static void io_queue_linked_timeout(struct io_kiocb *req)
3201 struct io_ring_ctx *ctx = req->ctx;
3204 * If the list is now empty, then our linked request finished before
3205 * we got a chance to setup the timer
3207 spin_lock_irq(&ctx->completion_lock);
3208 if (!list_empty(&req->link_list)) {
3209 struct io_timeout_data *data = &req->io->timeout;
3211 data->timer.function = io_link_timeout_fn;
3212 hrtimer_start(&data->timer, timespec64_to_ktime(data->ts),
3215 spin_unlock_irq(&ctx->completion_lock);
3217 /* drop submission reference */
3221 static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
3223 struct io_kiocb *nxt;
3225 if (!(req->flags & REQ_F_LINK))
3228 nxt = list_first_entry_or_null(&req->link_list, struct io_kiocb,
3230 if (!nxt || nxt->sqe->opcode != IORING_OP_LINK_TIMEOUT)
3233 req->flags |= REQ_F_LINK_TIMEOUT;
3237 static void __io_queue_sqe(struct io_kiocb *req)
3239 struct io_kiocb *linked_timeout;
3240 struct io_kiocb *nxt = NULL;
3244 linked_timeout = io_prep_linked_timeout(req);
3246 ret = io_issue_sqe(req, &nxt, true);
3249 * We async punt it if the file wasn't marked NOWAIT, or if the file
3250 * doesn't support non-blocking read/write attempts
3252 if (ret == -EAGAIN && (!(req->flags & REQ_F_NOWAIT) ||
3253 (req->flags & REQ_F_MUST_PUNT))) {
3254 if (req->work.flags & IO_WQ_WORK_NEEDS_FILES) {
3255 ret = io_grab_files(req);
3261 * Queued up for async execution, worker will release
3262 * submit reference when the iocb is actually submitted.
3264 io_queue_async_work(req);
3269 /* drop submission reference */
3272 if (linked_timeout) {
3274 io_queue_linked_timeout(linked_timeout);
3276 io_put_req(linked_timeout);
3279 /* and drop final reference, if we failed */
3281 io_cqring_add_event(req, ret);
3282 req_set_fail_links(req);
3293 static void io_queue_sqe(struct io_kiocb *req)
3297 if (unlikely(req->ctx->drain_next)) {
3298 req->flags |= REQ_F_IO_DRAIN;
3299 req->ctx->drain_next = false;
3301 req->ctx->drain_next = (req->flags & REQ_F_DRAIN_LINK);
3303 ret = io_req_defer(req);
3305 if (ret != -EIOCBQUEUED) {
3306 io_cqring_add_event(req, ret);
3307 req_set_fail_links(req);
3308 io_double_put_req(req);
3311 __io_queue_sqe(req);
3314 static inline void io_queue_link_head(struct io_kiocb *req)
3316 if (unlikely(req->flags & REQ_F_FAIL_LINK)) {
3317 io_cqring_add_event(req, -ECANCELED);
3318 io_double_put_req(req);
3323 #define SQE_VALID_FLAGS (IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK| \
3326 static bool io_submit_sqe(struct io_kiocb *req, struct io_submit_state *state,
3327 struct io_kiocb **link)
3329 struct io_ring_ctx *ctx = req->ctx;
3332 req->user_data = req->sqe->user_data;
3334 /* enforce forwards compatibility on users */
3335 if (unlikely(req->sqe->flags & ~SQE_VALID_FLAGS)) {
3340 ret = io_req_set_file(state, req);
3341 if (unlikely(ret)) {
3343 io_cqring_add_event(req, ret);
3344 io_double_put_req(req);
3349 * If we already have a head request, queue this one for async
3350 * submittal once the head completes. If we don't have a head but
3351 * IOSQE_IO_LINK is set in the sqe, start a new head. This one will be
3352 * submitted sync once the chain is complete. If none of those
3353 * conditions are true (normal request), then just queue it.
3356 struct io_kiocb *prev = *link;
3357 struct io_async_ctx *io;
3359 if (req->sqe->flags & IOSQE_IO_DRAIN)
3360 (*link)->flags |= REQ_F_DRAIN_LINK | REQ_F_IO_DRAIN;
3362 if (req->sqe->flags & IOSQE_IO_HARDLINK)
3363 req->flags |= REQ_F_HARDLINK;
3365 io = kmalloc(sizeof(*io), GFP_KERNEL);
3371 ret = io_req_defer_prep(req, io);
3374 /* fail even hard links since we don't submit */
3375 prev->flags |= REQ_F_FAIL_LINK;
3378 trace_io_uring_link(ctx, req, prev);
3379 list_add_tail(&req->link_list, &prev->link_list);
3380 } else if (req->sqe->flags & (IOSQE_IO_LINK|IOSQE_IO_HARDLINK)) {
3381 req->flags |= REQ_F_LINK;
3382 if (req->sqe->flags & IOSQE_IO_HARDLINK)
3383 req->flags |= REQ_F_HARDLINK;
3385 INIT_LIST_HEAD(&req->link_list);
3395 * Batched submission is done, ensure local IO is flushed out.
3397 static void io_submit_state_end(struct io_submit_state *state)
3399 blk_finish_plug(&state->plug);
3401 if (state->free_reqs)
3402 kmem_cache_free_bulk(req_cachep, state->free_reqs,
3403 &state->reqs[state->cur_req]);
3407 * Start submission side cache.
3409 static void io_submit_state_start(struct io_submit_state *state,
3410 unsigned int max_ios)
3412 blk_start_plug(&state->plug);
3413 state->free_reqs = 0;
3415 state->ios_left = max_ios;
3418 static void io_commit_sqring(struct io_ring_ctx *ctx)
3420 struct io_rings *rings = ctx->rings;
3422 if (ctx->cached_sq_head != READ_ONCE(rings->sq.head)) {
3424 * Ensure any loads from the SQEs are done at this point,
3425 * since once we write the new head, the application could
3426 * write new data to them.
3428 smp_store_release(&rings->sq.head, ctx->cached_sq_head);
3433 * Fetch an sqe, if one is available. Note that s->sqe will point to memory
3434 * that is mapped by userspace. This means that care needs to be taken to
3435 * ensure that reads are stable, as we cannot rely on userspace always
3436 * being a good citizen. If members of the sqe are validated and then later
3437 * used, it's important that those reads are done through READ_ONCE() to
3438 * prevent a re-load down the line.
3440 static bool io_get_sqring(struct io_ring_ctx *ctx, struct io_kiocb *req)
3442 struct io_rings *rings = ctx->rings;
3443 u32 *sq_array = ctx->sq_array;
3447 * The cached sq head (or cq tail) serves two purposes:
3449 * 1) allows us to batch the cost of updating the user visible
3451 * 2) allows the kernel side to track the head on its own, even
3452 * though the application is the one updating it.
3454 head = ctx->cached_sq_head;
3455 /* make sure SQ entry isn't read before tail */
3456 if (unlikely(head == smp_load_acquire(&rings->sq.tail)))
3459 head = READ_ONCE(sq_array[head & ctx->sq_mask]);
3460 if (likely(head < ctx->sq_entries)) {
3462 * All io need record the previous position, if LINK vs DARIN,
3463 * it can be used to mark the position of the first IO in the
3466 req->sequence = ctx->cached_sq_head;
3467 req->sqe = &ctx->sq_sqes[head];
3468 ctx->cached_sq_head++;
3472 /* drop invalid entries */
3473 ctx->cached_sq_head++;
3474 ctx->cached_sq_dropped++;
3475 WRITE_ONCE(rings->sq_dropped, ctx->cached_sq_dropped);
3479 static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
3480 struct file *ring_file, int ring_fd,
3481 struct mm_struct **mm, bool async)
3483 struct io_submit_state state, *statep = NULL;
3484 struct io_kiocb *link = NULL;
3485 int i, submitted = 0;
3486 bool mm_fault = false;
3488 /* if we have a backlog and couldn't flush it all, return BUSY */
3489 if (!list_empty(&ctx->cq_overflow_list) &&
3490 !io_cqring_overflow_flush(ctx, false))
3493 if (nr > IO_PLUG_THRESHOLD) {
3494 io_submit_state_start(&state, nr);
3498 for (i = 0; i < nr; i++) {
3499 struct io_kiocb *req;
3500 unsigned int sqe_flags;
3502 req = io_get_req(ctx, statep);
3503 if (unlikely(!req)) {
3505 submitted = -EAGAIN;
3508 if (!io_get_sqring(ctx, req)) {
3513 if (io_sqe_needs_user(req->sqe) && !*mm) {
3514 mm_fault = mm_fault || !mmget_not_zero(ctx->sqo_mm);
3516 use_mm(ctx->sqo_mm);
3522 sqe_flags = req->sqe->flags;
3524 req->ring_file = ring_file;
3525 req->ring_fd = ring_fd;
3526 req->has_user = *mm != NULL;
3527 req->in_async = async;
3528 req->needs_fixed_file = async;
3529 trace_io_uring_submit_sqe(ctx, req->sqe->user_data,
3531 if (!io_submit_sqe(req, statep, &link))
3534 * If previous wasn't linked and we have a linked command,
3535 * that's the end of the chain. Submit the previous link.
3537 if (!(sqe_flags & IOSQE_IO_LINK) && link) {
3538 io_queue_link_head(link);
3544 io_queue_link_head(link);
3546 io_submit_state_end(&state);
3548 /* Commit SQ ring head once we've consumed and submitted all SQEs */
3549 io_commit_sqring(ctx);
3554 static int io_sq_thread(void *data)
3556 struct io_ring_ctx *ctx = data;
3557 struct mm_struct *cur_mm = NULL;
3558 const struct cred *old_cred;
3559 mm_segment_t old_fs;
3562 unsigned long timeout;
3565 complete(&ctx->completions[1]);
3569 old_cred = override_creds(ctx->creds);
3571 ret = timeout = inflight = 0;
3572 while (!kthread_should_park()) {
3573 unsigned int to_submit;
3576 unsigned nr_events = 0;
3578 if (ctx->flags & IORING_SETUP_IOPOLL) {
3580 * inflight is the count of the maximum possible
3581 * entries we submitted, but it can be smaller
3582 * if we dropped some of them. If we don't have
3583 * poll entries available, then we know that we
3584 * have nothing left to poll for. Reset the
3585 * inflight count to zero in that case.
3587 mutex_lock(&ctx->uring_lock);
3588 if (!list_empty(&ctx->poll_list))
3589 __io_iopoll_check(ctx, &nr_events, 0);
3592 mutex_unlock(&ctx->uring_lock);
3595 * Normal IO, just pretend everything completed.
3596 * We don't have to poll completions for that.
3598 nr_events = inflight;
3601 inflight -= nr_events;
3603 timeout = jiffies + ctx->sq_thread_idle;
3606 to_submit = io_sqring_entries(ctx);
3609 * If submit got -EBUSY, flag us as needing the application
3610 * to enter the kernel to reap and flush events.
3612 if (!to_submit || ret == -EBUSY) {
3614 * We're polling. If we're within the defined idle
3615 * period, then let us spin without work before going
3616 * to sleep. The exception is if we got EBUSY doing
3617 * more IO, we should wait for the application to
3618 * reap events and wake us up.
3621 (!time_after(jiffies, timeout) && ret != -EBUSY)) {
3627 * Drop cur_mm before scheduling, we can't hold it for
3628 * long periods (or over schedule()). Do this before
3629 * adding ourselves to the waitqueue, as the unuse/drop
3638 prepare_to_wait(&ctx->sqo_wait, &wait,
3639 TASK_INTERRUPTIBLE);
3641 /* Tell userspace we may need a wakeup call */
3642 ctx->rings->sq_flags |= IORING_SQ_NEED_WAKEUP;
3643 /* make sure to read SQ tail after writing flags */
3646 to_submit = io_sqring_entries(ctx);
3647 if (!to_submit || ret == -EBUSY) {
3648 if (kthread_should_park()) {
3649 finish_wait(&ctx->sqo_wait, &wait);
3652 if (signal_pending(current))
3653 flush_signals(current);
3655 finish_wait(&ctx->sqo_wait, &wait);
3657 ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
3660 finish_wait(&ctx->sqo_wait, &wait);
3662 ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
3665 to_submit = min(to_submit, ctx->sq_entries);
3666 mutex_lock(&ctx->uring_lock);
3667 ret = io_submit_sqes(ctx, to_submit, NULL, -1, &cur_mm, true);
3668 mutex_unlock(&ctx->uring_lock);
3678 revert_creds(old_cred);
3685 struct io_wait_queue {
3686 struct wait_queue_entry wq;
3687 struct io_ring_ctx *ctx;
3689 unsigned nr_timeouts;
3692 static inline bool io_should_wake(struct io_wait_queue *iowq, bool noflush)
3694 struct io_ring_ctx *ctx = iowq->ctx;
3697 * Wake up if we have enough events, or if a timeout occured since we
3698 * started waiting. For timeouts, we always want to return to userspace,
3699 * regardless of event count.
3701 return io_cqring_events(ctx, noflush) >= iowq->to_wait ||
3702 atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
3705 static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode,
3706 int wake_flags, void *key)
3708 struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue,
3711 /* use noflush == true, as we can't safely rely on locking context */
3712 if (!io_should_wake(iowq, true))
3715 return autoremove_wake_function(curr, mode, wake_flags, key);
3719 * Wait until events become available, if we don't already have some. The
3720 * application must reap them itself, as they reside on the shared cq ring.
3722 static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
3723 const sigset_t __user *sig, size_t sigsz)
3725 struct io_wait_queue iowq = {
3728 .func = io_wake_function,
3729 .entry = LIST_HEAD_INIT(iowq.wq.entry),
3732 .to_wait = min_events,
3734 struct io_rings *rings = ctx->rings;
3737 if (io_cqring_events(ctx, false) >= min_events)
3741 #ifdef CONFIG_COMPAT
3742 if (in_compat_syscall())
3743 ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig,
3747 ret = set_user_sigmask(sig, sigsz);
3753 iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts);
3754 trace_io_uring_cqring_wait(ctx, min_events);
3756 prepare_to_wait_exclusive(&ctx->wait, &iowq.wq,
3757 TASK_INTERRUPTIBLE);
3758 if (io_should_wake(&iowq, false))
3761 if (signal_pending(current)) {
3766 finish_wait(&ctx->wait, &iowq.wq);
3768 restore_saved_sigmask_unless(ret == -EINTR);
3770 return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0;
3773 static void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
3775 #if defined(CONFIG_UNIX)
3776 if (ctx->ring_sock) {
3777 struct sock *sock = ctx->ring_sock->sk;
3778 struct sk_buff *skb;
3780 while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL)
3786 for (i = 0; i < ctx->nr_user_files; i++) {
3789 file = io_file_from_index(ctx, i);
3796 static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
3798 unsigned nr_tables, i;
3800 if (!ctx->file_table)
3803 __io_sqe_files_unregister(ctx);
3804 nr_tables = DIV_ROUND_UP(ctx->nr_user_files, IORING_MAX_FILES_TABLE);
3805 for (i = 0; i < nr_tables; i++)
3806 kfree(ctx->file_table[i].files);
3807 kfree(ctx->file_table);
3808 ctx->file_table = NULL;
3809 ctx->nr_user_files = 0;
3813 static void io_sq_thread_stop(struct io_ring_ctx *ctx)
3815 if (ctx->sqo_thread) {
3816 wait_for_completion(&ctx->completions[1]);
3818 * The park is a bit of a work-around, without it we get
3819 * warning spews on shutdown with SQPOLL set and affinity
3820 * set to a single CPU.
3822 kthread_park(ctx->sqo_thread);
3823 kthread_stop(ctx->sqo_thread);
3824 ctx->sqo_thread = NULL;
3828 static void io_finish_async(struct io_ring_ctx *ctx)
3830 io_sq_thread_stop(ctx);
3833 io_wq_destroy(ctx->io_wq);
3838 #if defined(CONFIG_UNIX)
3839 static void io_destruct_skb(struct sk_buff *skb)
3841 struct io_ring_ctx *ctx = skb->sk->sk_user_data;
3844 io_wq_flush(ctx->io_wq);
3846 unix_destruct_scm(skb);
3850 * Ensure the UNIX gc is aware of our file set, so we are certain that
3851 * the io_uring can be safely unregistered on process exit, even if we have
3852 * loops in the file referencing.
3854 static int __io_sqe_files_scm(struct io_ring_ctx *ctx, int nr, int offset)
3856 struct sock *sk = ctx->ring_sock->sk;
3857 struct scm_fp_list *fpl;
3858 struct sk_buff *skb;
3861 if (!capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) {
3862 unsigned long inflight = ctx->user->unix_inflight + nr;
3864 if (inflight > task_rlimit(current, RLIMIT_NOFILE))
3868 fpl = kzalloc(sizeof(*fpl), GFP_KERNEL);
3872 skb = alloc_skb(0, GFP_KERNEL);
3881 fpl->user = get_uid(ctx->user);
3882 for (i = 0; i < nr; i++) {
3883 struct file *file = io_file_from_index(ctx, i + offset);
3887 fpl->fp[nr_files] = get_file(file);
3888 unix_inflight(fpl->user, fpl->fp[nr_files]);
3893 fpl->max = SCM_MAX_FD;
3894 fpl->count = nr_files;
3895 UNIXCB(skb).fp = fpl;
3896 skb->destructor = io_destruct_skb;
3897 refcount_add(skb->truesize, &sk->sk_wmem_alloc);
3898 skb_queue_head(&sk->sk_receive_queue, skb);
3900 for (i = 0; i < nr_files; i++)
3911 * If UNIX sockets are enabled, fd passing can cause a reference cycle which
3912 * causes regular reference counting to break down. We rely on the UNIX
3913 * garbage collection to take care of this problem for us.
3915 static int io_sqe_files_scm(struct io_ring_ctx *ctx)
3917 unsigned left, total;
3921 left = ctx->nr_user_files;
3923 unsigned this_files = min_t(unsigned, left, SCM_MAX_FD);
3925 ret = __io_sqe_files_scm(ctx, this_files, total);
3929 total += this_files;
3935 while (total < ctx->nr_user_files) {
3936 struct file *file = io_file_from_index(ctx, total);
3946 static int io_sqe_files_scm(struct io_ring_ctx *ctx)
3952 static int io_sqe_alloc_file_tables(struct io_ring_ctx *ctx, unsigned nr_tables,
3957 for (i = 0; i < nr_tables; i++) {
3958 struct fixed_file_table *table = &ctx->file_table[i];
3959 unsigned this_files;
3961 this_files = min(nr_files, IORING_MAX_FILES_TABLE);
3962 table->files = kcalloc(this_files, sizeof(struct file *),
3966 nr_files -= this_files;
3972 for (i = 0; i < nr_tables; i++) {
3973 struct fixed_file_table *table = &ctx->file_table[i];
3974 kfree(table->files);
3979 static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
3982 __s32 __user *fds = (__s32 __user *) arg;
3987 if (ctx->file_table)
3991 if (nr_args > IORING_MAX_FIXED_FILES)
3994 nr_tables = DIV_ROUND_UP(nr_args, IORING_MAX_FILES_TABLE);
3995 ctx->file_table = kcalloc(nr_tables, sizeof(struct fixed_file_table),
3997 if (!ctx->file_table)
4000 if (io_sqe_alloc_file_tables(ctx, nr_tables, nr_args)) {
4001 kfree(ctx->file_table);
4002 ctx->file_table = NULL;
4006 for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
4007 struct fixed_file_table *table;
4011 if (copy_from_user(&fd, &fds[i], sizeof(fd)))
4013 /* allow sparse sets */
4019 table = &ctx->file_table[i >> IORING_FILE_TABLE_SHIFT];
4020 index = i & IORING_FILE_TABLE_MASK;
4021 table->files[index] = fget(fd);
4024 if (!table->files[index])
4027 * Don't allow io_uring instances to be registered. If UNIX
4028 * isn't enabled, then this causes a reference cycle and this
4029 * instance can never get freed. If UNIX is enabled we'll
4030 * handle it just fine, but there's still no point in allowing
4031 * a ring fd as it doesn't support regular read/write anyway.
4033 if (table->files[index]->f_op == &io_uring_fops) {
4034 fput(table->files[index]);
4041 for (i = 0; i < ctx->nr_user_files; i++) {
4044 file = io_file_from_index(ctx, i);
4048 for (i = 0; i < nr_tables; i++)
4049 kfree(ctx->file_table[i].files);
4051 kfree(ctx->file_table);
4052 ctx->file_table = NULL;
4053 ctx->nr_user_files = 0;
4057 ret = io_sqe_files_scm(ctx);
4059 io_sqe_files_unregister(ctx);
4064 static void io_sqe_file_unregister(struct io_ring_ctx *ctx, int index)
4066 #if defined(CONFIG_UNIX)
4067 struct file *file = io_file_from_index(ctx, index);
4068 struct sock *sock = ctx->ring_sock->sk;
4069 struct sk_buff_head list, *head = &sock->sk_receive_queue;
4070 struct sk_buff *skb;
4073 __skb_queue_head_init(&list);
4076 * Find the skb that holds this file in its SCM_RIGHTS. When found,
4077 * remove this entry and rearrange the file array.
4079 skb = skb_dequeue(head);
4081 struct scm_fp_list *fp;
4083 fp = UNIXCB(skb).fp;
4084 for (i = 0; i < fp->count; i++) {
4087 if (fp->fp[i] != file)
4090 unix_notinflight(fp->user, fp->fp[i]);
4091 left = fp->count - 1 - i;
4093 memmove(&fp->fp[i], &fp->fp[i + 1],
4094 left * sizeof(struct file *));
4101 __skb_queue_tail(&list, skb);
4111 __skb_queue_tail(&list, skb);
4113 skb = skb_dequeue(head);
4116 if (skb_peek(&list)) {
4117 spin_lock_irq(&head->lock);
4118 while ((skb = __skb_dequeue(&list)) != NULL)
4119 __skb_queue_tail(head, skb);
4120 spin_unlock_irq(&head->lock);
4123 fput(io_file_from_index(ctx, index));
4127 static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file,
4130 #if defined(CONFIG_UNIX)
4131 struct sock *sock = ctx->ring_sock->sk;
4132 struct sk_buff_head *head = &sock->sk_receive_queue;
4133 struct sk_buff *skb;
4136 * See if we can merge this file into an existing skb SCM_RIGHTS
4137 * file set. If there's no room, fall back to allocating a new skb
4138 * and filling it in.
4140 spin_lock_irq(&head->lock);
4141 skb = skb_peek(head);
4143 struct scm_fp_list *fpl = UNIXCB(skb).fp;
4145 if (fpl->count < SCM_MAX_FD) {
4146 __skb_unlink(skb, head);
4147 spin_unlock_irq(&head->lock);
4148 fpl->fp[fpl->count] = get_file(file);
4149 unix_inflight(fpl->user, fpl->fp[fpl->count]);
4151 spin_lock_irq(&head->lock);
4152 __skb_queue_head(head, skb);
4157 spin_unlock_irq(&head->lock);
4164 return __io_sqe_files_scm(ctx, 1, index);
4170 static int io_sqe_files_update(struct io_ring_ctx *ctx, void __user *arg,
4173 struct io_uring_files_update up;
4178 if (!ctx->file_table)
4182 if (copy_from_user(&up, arg, sizeof(up)))
4184 if (check_add_overflow(up.offset, nr_args, &done))
4186 if (done > ctx->nr_user_files)
4190 fds = (__s32 __user *) up.fds;
4192 struct fixed_file_table *table;
4196 if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
4200 i = array_index_nospec(up.offset, ctx->nr_user_files);
4201 table = &ctx->file_table[i >> IORING_FILE_TABLE_SHIFT];
4202 index = i & IORING_FILE_TABLE_MASK;
4203 if (table->files[index]) {
4204 io_sqe_file_unregister(ctx, i);
4205 table->files[index] = NULL;
4216 * Don't allow io_uring instances to be registered. If
4217 * UNIX isn't enabled, then this causes a reference
4218 * cycle and this instance can never get freed. If UNIX
4219 * is enabled we'll handle it just fine, but there's
4220 * still no point in allowing a ring fd as it doesn't
4221 * support regular read/write anyway.
4223 if (file->f_op == &io_uring_fops) {
4228 table->files[index] = file;
4229 err = io_sqe_file_register(ctx, file, i);
4238 return done ? done : err;
4241 static void io_put_work(struct io_wq_work *work)
4243 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
4248 static void io_get_work(struct io_wq_work *work)
4250 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
4252 refcount_inc(&req->refs);
4255 static int io_sq_offload_start(struct io_ring_ctx *ctx,
4256 struct io_uring_params *p)
4258 struct io_wq_data data;
4259 unsigned concurrency;
4262 init_waitqueue_head(&ctx->sqo_wait);
4263 mmgrab(current->mm);
4264 ctx->sqo_mm = current->mm;
4266 if (ctx->flags & IORING_SETUP_SQPOLL) {
4268 if (!capable(CAP_SYS_ADMIN))
4271 ctx->sq_thread_idle = msecs_to_jiffies(p->sq_thread_idle);
4272 if (!ctx->sq_thread_idle)
4273 ctx->sq_thread_idle = HZ;
4275 if (p->flags & IORING_SETUP_SQ_AFF) {
4276 int cpu = p->sq_thread_cpu;
4279 if (cpu >= nr_cpu_ids)
4281 if (!cpu_online(cpu))
4284 ctx->sqo_thread = kthread_create_on_cpu(io_sq_thread,
4288 ctx->sqo_thread = kthread_create(io_sq_thread, ctx,
4291 if (IS_ERR(ctx->sqo_thread)) {
4292 ret = PTR_ERR(ctx->sqo_thread);
4293 ctx->sqo_thread = NULL;
4296 wake_up_process(ctx->sqo_thread);
4297 } else if (p->flags & IORING_SETUP_SQ_AFF) {
4298 /* Can't have SQ_AFF without SQPOLL */
4303 data.mm = ctx->sqo_mm;
4304 data.user = ctx->user;
4305 data.creds = ctx->creds;
4306 data.get_work = io_get_work;
4307 data.put_work = io_put_work;
4309 /* Do QD, or 4 * CPUS, whatever is smallest */
4310 concurrency = min(ctx->sq_entries, 4 * num_online_cpus());
4311 ctx->io_wq = io_wq_create(concurrency, &data);
4312 if (IS_ERR(ctx->io_wq)) {
4313 ret = PTR_ERR(ctx->io_wq);
4320 io_finish_async(ctx);
4321 mmdrop(ctx->sqo_mm);
4326 static void io_unaccount_mem(struct user_struct *user, unsigned long nr_pages)
4328 atomic_long_sub(nr_pages, &user->locked_vm);
4331 static int io_account_mem(struct user_struct *user, unsigned long nr_pages)
4333 unsigned long page_limit, cur_pages, new_pages;
4335 /* Don't allow more pages than we can safely lock */
4336 page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
4339 cur_pages = atomic_long_read(&user->locked_vm);
4340 new_pages = cur_pages + nr_pages;
4341 if (new_pages > page_limit)
4343 } while (atomic_long_cmpxchg(&user->locked_vm, cur_pages,
4344 new_pages) != cur_pages);
4349 static void io_mem_free(void *ptr)
4356 page = virt_to_head_page(ptr);
4357 if (put_page_testzero(page))
4358 free_compound_page(page);
4361 static void *io_mem_alloc(size_t size)
4363 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP |
4366 return (void *) __get_free_pages(gfp_flags, get_order(size));
4369 static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries,
4372 struct io_rings *rings;
4373 size_t off, sq_array_size;
4375 off = struct_size(rings, cqes, cq_entries);
4376 if (off == SIZE_MAX)
4380 off = ALIGN(off, SMP_CACHE_BYTES);
4385 sq_array_size = array_size(sizeof(u32), sq_entries);
4386 if (sq_array_size == SIZE_MAX)
4389 if (check_add_overflow(off, sq_array_size, &off))
4398 static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries)
4402 pages = (size_t)1 << get_order(
4403 rings_size(sq_entries, cq_entries, NULL));
4404 pages += (size_t)1 << get_order(
4405 array_size(sizeof(struct io_uring_sqe), sq_entries));
4410 static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx)
4414 if (!ctx->user_bufs)
4417 for (i = 0; i < ctx->nr_user_bufs; i++) {
4418 struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
4420 for (j = 0; j < imu->nr_bvecs; j++)
4421 put_user_page(imu->bvec[j].bv_page);
4423 if (ctx->account_mem)
4424 io_unaccount_mem(ctx->user, imu->nr_bvecs);
4429 kfree(ctx->user_bufs);
4430 ctx->user_bufs = NULL;
4431 ctx->nr_user_bufs = 0;
4435 static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst,
4436 void __user *arg, unsigned index)
4438 struct iovec __user *src;
4440 #ifdef CONFIG_COMPAT
4442 struct compat_iovec __user *ciovs;
4443 struct compat_iovec ciov;
4445 ciovs = (struct compat_iovec __user *) arg;
4446 if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov)))
4449 dst->iov_base = (void __user *) (unsigned long) ciov.iov_base;
4450 dst->iov_len = ciov.iov_len;
4454 src = (struct iovec __user *) arg;
4455 if (copy_from_user(dst, &src[index], sizeof(*dst)))
4460 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
4463 struct vm_area_struct **vmas = NULL;
4464 struct page **pages = NULL;
4465 int i, j, got_pages = 0;
4470 if (!nr_args || nr_args > UIO_MAXIOV)
4473 ctx->user_bufs = kcalloc(nr_args, sizeof(struct io_mapped_ubuf),
4475 if (!ctx->user_bufs)
4478 for (i = 0; i < nr_args; i++) {
4479 struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
4480 unsigned long off, start, end, ubuf;
4485 ret = io_copy_iov(ctx, &iov, arg, i);
4490 * Don't impose further limits on the size and buffer
4491 * constraints here, we'll -EINVAL later when IO is
4492 * submitted if they are wrong.
4495 if (!iov.iov_base || !iov.iov_len)
4498 /* arbitrary limit, but we need something */
4499 if (iov.iov_len > SZ_1G)
4502 ubuf = (unsigned long) iov.iov_base;
4503 end = (ubuf + iov.iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
4504 start = ubuf >> PAGE_SHIFT;
4505 nr_pages = end - start;
4507 if (ctx->account_mem) {
4508 ret = io_account_mem(ctx->user, nr_pages);
4514 if (!pages || nr_pages > got_pages) {
4517 pages = kvmalloc_array(nr_pages, sizeof(struct page *),
4519 vmas = kvmalloc_array(nr_pages,
4520 sizeof(struct vm_area_struct *),
4522 if (!pages || !vmas) {
4524 if (ctx->account_mem)
4525 io_unaccount_mem(ctx->user, nr_pages);
4528 got_pages = nr_pages;
4531 imu->bvec = kvmalloc_array(nr_pages, sizeof(struct bio_vec),
4535 if (ctx->account_mem)
4536 io_unaccount_mem(ctx->user, nr_pages);
4541 down_read(¤t->mm->mmap_sem);
4542 pret = get_user_pages(ubuf, nr_pages,
4543 FOLL_WRITE | FOLL_LONGTERM,
4545 if (pret == nr_pages) {
4546 /* don't support file backed memory */
4547 for (j = 0; j < nr_pages; j++) {
4548 struct vm_area_struct *vma = vmas[j];
4551 !is_file_hugepages(vma->vm_file)) {
4557 ret = pret < 0 ? pret : -EFAULT;
4559 up_read(¤t->mm->mmap_sem);
4562 * if we did partial map, or found file backed vmas,
4563 * release any pages we did get
4566 put_user_pages(pages, pret);
4567 if (ctx->account_mem)
4568 io_unaccount_mem(ctx->user, nr_pages);
4573 off = ubuf & ~PAGE_MASK;
4575 for (j = 0; j < nr_pages; j++) {
4578 vec_len = min_t(size_t, size, PAGE_SIZE - off);
4579 imu->bvec[j].bv_page = pages[j];
4580 imu->bvec[j].bv_len = vec_len;
4581 imu->bvec[j].bv_offset = off;
4585 /* store original address for later verification */
4587 imu->len = iov.iov_len;
4588 imu->nr_bvecs = nr_pages;
4590 ctx->nr_user_bufs++;
4598 io_sqe_buffer_unregister(ctx);
4602 static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg)
4604 __s32 __user *fds = arg;
4610 if (copy_from_user(&fd, fds, sizeof(*fds)))
4613 ctx->cq_ev_fd = eventfd_ctx_fdget(fd);
4614 if (IS_ERR(ctx->cq_ev_fd)) {
4615 int ret = PTR_ERR(ctx->cq_ev_fd);
4616 ctx->cq_ev_fd = NULL;
4623 static int io_eventfd_unregister(struct io_ring_ctx *ctx)
4625 if (ctx->cq_ev_fd) {
4626 eventfd_ctx_put(ctx->cq_ev_fd);
4627 ctx->cq_ev_fd = NULL;
4634 static void io_ring_ctx_free(struct io_ring_ctx *ctx)
4636 io_finish_async(ctx);
4638 mmdrop(ctx->sqo_mm);
4640 io_iopoll_reap_events(ctx);
4641 io_sqe_buffer_unregister(ctx);
4642 io_sqe_files_unregister(ctx);
4643 io_eventfd_unregister(ctx);
4645 #if defined(CONFIG_UNIX)
4646 if (ctx->ring_sock) {
4647 ctx->ring_sock->file = NULL; /* so that iput() is called */
4648 sock_release(ctx->ring_sock);
4652 io_mem_free(ctx->rings);
4653 io_mem_free(ctx->sq_sqes);
4655 percpu_ref_exit(&ctx->refs);
4656 if (ctx->account_mem)
4657 io_unaccount_mem(ctx->user,
4658 ring_pages(ctx->sq_entries, ctx->cq_entries));
4659 free_uid(ctx->user);
4660 put_cred(ctx->creds);
4661 kfree(ctx->completions);
4662 kfree(ctx->cancel_hash);
4663 kmem_cache_free(req_cachep, ctx->fallback_req);
4667 static __poll_t io_uring_poll(struct file *file, poll_table *wait)
4669 struct io_ring_ctx *ctx = file->private_data;
4672 poll_wait(file, &ctx->cq_wait, wait);
4674 * synchronizes with barrier from wq_has_sleeper call in
4678 if (READ_ONCE(ctx->rings->sq.tail) - ctx->cached_sq_head !=
4679 ctx->rings->sq_ring_entries)
4680 mask |= EPOLLOUT | EPOLLWRNORM;
4681 if (READ_ONCE(ctx->rings->cq.head) != ctx->cached_cq_tail)
4682 mask |= EPOLLIN | EPOLLRDNORM;
4687 static int io_uring_fasync(int fd, struct file *file, int on)
4689 struct io_ring_ctx *ctx = file->private_data;
4691 return fasync_helper(fd, file, on, &ctx->cq_fasync);
4694 static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
4696 mutex_lock(&ctx->uring_lock);
4697 percpu_ref_kill(&ctx->refs);
4698 mutex_unlock(&ctx->uring_lock);
4700 io_kill_timeouts(ctx);
4701 io_poll_remove_all(ctx);
4704 io_wq_cancel_all(ctx->io_wq);
4706 io_iopoll_reap_events(ctx);
4707 /* if we failed setting up the ctx, we might not have any rings */
4709 io_cqring_overflow_flush(ctx, true);
4710 wait_for_completion(&ctx->completions[0]);
4711 io_ring_ctx_free(ctx);
4714 static int io_uring_release(struct inode *inode, struct file *file)
4716 struct io_ring_ctx *ctx = file->private_data;
4718 file->private_data = NULL;
4719 io_ring_ctx_wait_and_kill(ctx);
4723 static void io_uring_cancel_files(struct io_ring_ctx *ctx,
4724 struct files_struct *files)
4726 struct io_kiocb *req;
4729 while (!list_empty_careful(&ctx->inflight_list)) {
4730 struct io_kiocb *cancel_req = NULL;
4732 spin_lock_irq(&ctx->inflight_lock);
4733 list_for_each_entry(req, &ctx->inflight_list, inflight_entry) {
4734 if (req->work.files != files)
4736 /* req is being completed, ignore */
4737 if (!refcount_inc_not_zero(&req->refs))
4743 prepare_to_wait(&ctx->inflight_wait, &wait,
4744 TASK_UNINTERRUPTIBLE);
4745 spin_unlock_irq(&ctx->inflight_lock);
4747 /* We need to keep going until we don't find a matching req */
4751 io_wq_cancel_work(ctx->io_wq, &cancel_req->work);
4752 io_put_req(cancel_req);
4755 finish_wait(&ctx->inflight_wait, &wait);
4758 static int io_uring_flush(struct file *file, void *data)
4760 struct io_ring_ctx *ctx = file->private_data;
4762 io_uring_cancel_files(ctx, data);
4763 if (fatal_signal_pending(current) || (current->flags & PF_EXITING)) {
4764 io_cqring_overflow_flush(ctx, true);
4765 io_wq_cancel_all(ctx->io_wq);
4770 static void *io_uring_validate_mmap_request(struct file *file,
4771 loff_t pgoff, size_t sz)
4773 struct io_ring_ctx *ctx = file->private_data;
4774 loff_t offset = pgoff << PAGE_SHIFT;
4779 case IORING_OFF_SQ_RING:
4780 case IORING_OFF_CQ_RING:
4783 case IORING_OFF_SQES:
4787 return ERR_PTR(-EINVAL);
4790 page = virt_to_head_page(ptr);
4791 if (sz > page_size(page))
4792 return ERR_PTR(-EINVAL);
4799 static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
4801 size_t sz = vma->vm_end - vma->vm_start;
4805 ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz);
4807 return PTR_ERR(ptr);
4809 pfn = virt_to_phys(ptr) >> PAGE_SHIFT;
4810 return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot);
4813 #else /* !CONFIG_MMU */
4815 static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
4817 return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -EINVAL;
4820 static unsigned int io_uring_nommu_mmap_capabilities(struct file *file)
4822 return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE;
4825 static unsigned long io_uring_nommu_get_unmapped_area(struct file *file,
4826 unsigned long addr, unsigned long len,
4827 unsigned long pgoff, unsigned long flags)
4831 ptr = io_uring_validate_mmap_request(file, pgoff, len);
4833 return PTR_ERR(ptr);
4835 return (unsigned long) ptr;
4838 #endif /* !CONFIG_MMU */
4840 SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
4841 u32, min_complete, u32, flags, const sigset_t __user *, sig,
4844 struct io_ring_ctx *ctx;
4849 if (flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP))
4857 if (f.file->f_op != &io_uring_fops)
4861 ctx = f.file->private_data;
4862 if (!percpu_ref_tryget(&ctx->refs))
4866 * For SQ polling, the thread will do all submissions and completions.
4867 * Just return the requested submit count, and wake the thread if
4871 if (ctx->flags & IORING_SETUP_SQPOLL) {
4872 if (!list_empty_careful(&ctx->cq_overflow_list))
4873 io_cqring_overflow_flush(ctx, false);
4874 if (flags & IORING_ENTER_SQ_WAKEUP)
4875 wake_up(&ctx->sqo_wait);
4876 submitted = to_submit;
4877 } else if (to_submit) {
4878 struct mm_struct *cur_mm;
4880 to_submit = min(to_submit, ctx->sq_entries);
4881 mutex_lock(&ctx->uring_lock);
4882 /* already have mm, so io_submit_sqes() won't try to grab it */
4883 cur_mm = ctx->sqo_mm;
4884 submitted = io_submit_sqes(ctx, to_submit, f.file, fd,
4886 mutex_unlock(&ctx->uring_lock);
4888 if (flags & IORING_ENTER_GETEVENTS) {
4889 unsigned nr_events = 0;
4891 min_complete = min(min_complete, ctx->cq_entries);
4893 if (ctx->flags & IORING_SETUP_IOPOLL) {
4894 ret = io_iopoll_check(ctx, &nr_events, min_complete);
4896 ret = io_cqring_wait(ctx, min_complete, sig, sigsz);
4900 percpu_ref_put(&ctx->refs);
4903 return submitted ? submitted : ret;
4906 static const struct file_operations io_uring_fops = {
4907 .release = io_uring_release,
4908 .flush = io_uring_flush,
4909 .mmap = io_uring_mmap,
4911 .get_unmapped_area = io_uring_nommu_get_unmapped_area,
4912 .mmap_capabilities = io_uring_nommu_mmap_capabilities,
4914 .poll = io_uring_poll,
4915 .fasync = io_uring_fasync,
4918 static int io_allocate_scq_urings(struct io_ring_ctx *ctx,
4919 struct io_uring_params *p)
4921 struct io_rings *rings;
4922 size_t size, sq_array_offset;
4924 size = rings_size(p->sq_entries, p->cq_entries, &sq_array_offset);
4925 if (size == SIZE_MAX)
4928 rings = io_mem_alloc(size);
4933 ctx->sq_array = (u32 *)((char *)rings + sq_array_offset);
4934 rings->sq_ring_mask = p->sq_entries - 1;
4935 rings->cq_ring_mask = p->cq_entries - 1;
4936 rings->sq_ring_entries = p->sq_entries;
4937 rings->cq_ring_entries = p->cq_entries;
4938 ctx->sq_mask = rings->sq_ring_mask;
4939 ctx->cq_mask = rings->cq_ring_mask;
4940 ctx->sq_entries = rings->sq_ring_entries;
4941 ctx->cq_entries = rings->cq_ring_entries;
4943 size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
4944 if (size == SIZE_MAX) {
4945 io_mem_free(ctx->rings);
4950 ctx->sq_sqes = io_mem_alloc(size);
4951 if (!ctx->sq_sqes) {
4952 io_mem_free(ctx->rings);
4961 * Allocate an anonymous fd, this is what constitutes the application
4962 * visible backing of an io_uring instance. The application mmaps this
4963 * fd to gain access to the SQ/CQ ring details. If UNIX sockets are enabled,
4964 * we have to tie this fd to a socket for file garbage collection purposes.
4966 static int io_uring_get_fd(struct io_ring_ctx *ctx)
4971 #if defined(CONFIG_UNIX)
4972 ret = sock_create_kern(&init_net, PF_UNIX, SOCK_RAW, IPPROTO_IP,
4978 ret = get_unused_fd_flags(O_RDWR | O_CLOEXEC);
4982 file = anon_inode_getfile("[io_uring]", &io_uring_fops, ctx,
4983 O_RDWR | O_CLOEXEC);
4986 ret = PTR_ERR(file);
4990 #if defined(CONFIG_UNIX)
4991 ctx->ring_sock->file = file;
4992 ctx->ring_sock->sk->sk_user_data = ctx;
4994 fd_install(ret, file);
4997 #if defined(CONFIG_UNIX)
4998 sock_release(ctx->ring_sock);
4999 ctx->ring_sock = NULL;
5004 static int io_uring_create(unsigned entries, struct io_uring_params *p)
5006 struct user_struct *user = NULL;
5007 struct io_ring_ctx *ctx;
5011 if (!entries || entries > IORING_MAX_ENTRIES)
5015 * Use twice as many entries for the CQ ring. It's possible for the
5016 * application to drive a higher depth than the size of the SQ ring,
5017 * since the sqes are only used at submission time. This allows for
5018 * some flexibility in overcommitting a bit. If the application has
5019 * set IORING_SETUP_CQSIZE, it will have passed in the desired number
5020 * of CQ ring entries manually.
5022 p->sq_entries = roundup_pow_of_two(entries);
5023 if (p->flags & IORING_SETUP_CQSIZE) {
5025 * If IORING_SETUP_CQSIZE is set, we do the same roundup
5026 * to a power-of-two, if it isn't already. We do NOT impose
5027 * any cq vs sq ring sizing.
5029 if (p->cq_entries < p->sq_entries || p->cq_entries > IORING_MAX_CQ_ENTRIES)
5031 p->cq_entries = roundup_pow_of_two(p->cq_entries);
5033 p->cq_entries = 2 * p->sq_entries;
5036 user = get_uid(current_user());
5037 account_mem = !capable(CAP_IPC_LOCK);
5040 ret = io_account_mem(user,
5041 ring_pages(p->sq_entries, p->cq_entries));
5048 ctx = io_ring_ctx_alloc(p);
5051 io_unaccount_mem(user, ring_pages(p->sq_entries,
5056 ctx->compat = in_compat_syscall();
5057 ctx->account_mem = account_mem;
5059 ctx->creds = get_current_cred();
5061 ret = io_allocate_scq_urings(ctx, p);
5065 ret = io_sq_offload_start(ctx, p);
5069 memset(&p->sq_off, 0, sizeof(p->sq_off));
5070 p->sq_off.head = offsetof(struct io_rings, sq.head);
5071 p->sq_off.tail = offsetof(struct io_rings, sq.tail);
5072 p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask);
5073 p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries);
5074 p->sq_off.flags = offsetof(struct io_rings, sq_flags);
5075 p->sq_off.dropped = offsetof(struct io_rings, sq_dropped);
5076 p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings;
5078 memset(&p->cq_off, 0, sizeof(p->cq_off));
5079 p->cq_off.head = offsetof(struct io_rings, cq.head);
5080 p->cq_off.tail = offsetof(struct io_rings, cq.tail);
5081 p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask);
5082 p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries);
5083 p->cq_off.overflow = offsetof(struct io_rings, cq_overflow);
5084 p->cq_off.cqes = offsetof(struct io_rings, cqes);
5087 * Install ring fd as the very last thing, so we don't risk someone
5088 * having closed it before we finish setup
5090 ret = io_uring_get_fd(ctx);
5094 p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP |
5095 IORING_FEAT_SUBMIT_STABLE;
5096 trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags);
5099 io_ring_ctx_wait_and_kill(ctx);
5104 * Sets up an aio uring context, and returns the fd. Applications asks for a
5105 * ring size, we return the actual sq/cq ring sizes (among other things) in the
5106 * params structure passed in.
5108 static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
5110 struct io_uring_params p;
5114 if (copy_from_user(&p, params, sizeof(p)))
5116 for (i = 0; i < ARRAY_SIZE(p.resv); i++) {
5121 if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL |
5122 IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE))
5125 ret = io_uring_create(entries, &p);
5129 if (copy_to_user(params, &p, sizeof(p)))
5135 SYSCALL_DEFINE2(io_uring_setup, u32, entries,
5136 struct io_uring_params __user *, params)
5138 return io_uring_setup(entries, params);
5141 static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
5142 void __user *arg, unsigned nr_args)
5143 __releases(ctx->uring_lock)
5144 __acquires(ctx->uring_lock)
5149 * We're inside the ring mutex, if the ref is already dying, then
5150 * someone else killed the ctx or is already going through
5151 * io_uring_register().
5153 if (percpu_ref_is_dying(&ctx->refs))
5156 percpu_ref_kill(&ctx->refs);
5159 * Drop uring mutex before waiting for references to exit. If another
5160 * thread is currently inside io_uring_enter() it might need to grab
5161 * the uring_lock to make progress. If we hold it here across the drain
5162 * wait, then we can deadlock. It's safe to drop the mutex here, since
5163 * no new references will come in after we've killed the percpu ref.
5165 mutex_unlock(&ctx->uring_lock);
5166 wait_for_completion(&ctx->completions[0]);
5167 mutex_lock(&ctx->uring_lock);
5170 case IORING_REGISTER_BUFFERS:
5171 ret = io_sqe_buffer_register(ctx, arg, nr_args);
5173 case IORING_UNREGISTER_BUFFERS:
5177 ret = io_sqe_buffer_unregister(ctx);
5179 case IORING_REGISTER_FILES:
5180 ret = io_sqe_files_register(ctx, arg, nr_args);
5182 case IORING_UNREGISTER_FILES:
5186 ret = io_sqe_files_unregister(ctx);
5188 case IORING_REGISTER_FILES_UPDATE:
5189 ret = io_sqe_files_update(ctx, arg, nr_args);
5191 case IORING_REGISTER_EVENTFD:
5195 ret = io_eventfd_register(ctx, arg);
5197 case IORING_UNREGISTER_EVENTFD:
5201 ret = io_eventfd_unregister(ctx);
5208 /* bring the ctx back to life */
5209 reinit_completion(&ctx->completions[0]);
5210 percpu_ref_reinit(&ctx->refs);
5214 SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode,
5215 void __user *, arg, unsigned int, nr_args)
5217 struct io_ring_ctx *ctx;
5226 if (f.file->f_op != &io_uring_fops)
5229 ctx = f.file->private_data;
5231 mutex_lock(&ctx->uring_lock);
5232 ret = __io_uring_register(ctx, opcode, arg, nr_args);
5233 mutex_unlock(&ctx->uring_lock);
5234 trace_io_uring_register(ctx, opcode, ctx->nr_user_files, ctx->nr_user_bufs,
5235 ctx->cq_ev_fd != NULL, ret);
5241 static int __init io_uring_init(void)
5243 req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC);
5246 __initcall(io_uring_init);