1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/errno.h>
5 #include <linux/file.h>
6 #include <linux/blk-mq.h>
8 #include <linux/slab.h>
9 #include <linux/fsnotify.h>
10 #include <linux/poll.h>
11 #include <linux/nospec.h>
12 #include <linux/compat.h>
13 #include <linux/io_uring.h>
15 #include <uapi/linux/io_uring.h>
24 /* NOTE: kiocb has the file as the first member, so don't do it here */
31 static inline bool io_file_supports_nowait(struct io_kiocb *req)
33 return req->flags & REQ_F_SUPPORT_NOWAIT;
37 static int io_iov_compat_buffer_select_prep(struct io_rw *rw)
39 struct compat_iovec __user *uiov;
42 uiov = u64_to_user_ptr(rw->addr);
43 if (!access_ok(uiov, sizeof(*uiov)))
45 if (__get_user(clen, &uiov->iov_len))
55 static int io_iov_buffer_select_prep(struct io_kiocb *req)
57 struct iovec __user *uiov;
59 struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
66 return io_iov_compat_buffer_select_prep(rw);
69 uiov = u64_to_user_ptr(rw->addr);
70 if (copy_from_user(&iov, uiov, sizeof(*uiov)))
72 rw->len = iov.iov_len;
76 int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
78 struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
82 rw->kiocb.ki_pos = READ_ONCE(sqe->off);
83 /* used for fixed read/write too - just read unconditionally */
84 req->buf_index = READ_ONCE(sqe->buf_index);
86 if (req->opcode == IORING_OP_READ_FIXED ||
87 req->opcode == IORING_OP_WRITE_FIXED) {
88 struct io_ring_ctx *ctx = req->ctx;
91 if (unlikely(req->buf_index >= ctx->nr_user_bufs))
93 index = array_index_nospec(req->buf_index, ctx->nr_user_bufs);
94 req->imu = ctx->user_bufs[index];
95 io_req_set_rsrc_node(req, ctx, 0);
98 ioprio = READ_ONCE(sqe->ioprio);
100 ret = ioprio_check_cap(ioprio);
104 rw->kiocb.ki_ioprio = ioprio;
106 rw->kiocb.ki_ioprio = get_current_ioprio();
108 rw->kiocb.dio_complete = NULL;
110 rw->addr = READ_ONCE(sqe->addr);
111 rw->len = READ_ONCE(sqe->len);
112 rw->flags = READ_ONCE(sqe->rw_flags);
114 /* Have to do this validation here, as this is in io_read() rw->len might
115 * have chanaged due to buffer selection
117 if (req->opcode == IORING_OP_READV && req->flags & REQ_F_BUFFER_SELECT) {
118 ret = io_iov_buffer_select_prep(req);
126 void io_readv_writev_cleanup(struct io_kiocb *req)
128 struct io_async_rw *io = req->async_data;
130 kfree(io->free_iovec);
133 static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
139 case -ERESTARTNOINTR:
140 case -ERESTARTNOHAND:
141 case -ERESTART_RESTARTBLOCK:
143 * We can't just restart the syscall, since previously
144 * submitted sqes may already be in progress. Just fail this
150 kiocb->ki_complete(kiocb, ret);
154 static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req)
156 struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
158 if (rw->kiocb.ki_pos != -1)
159 return &rw->kiocb.ki_pos;
161 if (!(req->file->f_mode & FMODE_STREAM)) {
162 req->flags |= REQ_F_CUR_POS;
163 rw->kiocb.ki_pos = req->file->f_pos;
164 return &rw->kiocb.ki_pos;
167 rw->kiocb.ki_pos = 0;
171 static void io_req_task_queue_reissue(struct io_kiocb *req)
173 req->io_task_work.func = io_queue_iowq;
174 io_req_task_work_add(req);
178 static bool io_resubmit_prep(struct io_kiocb *req)
180 struct io_async_rw *io = req->async_data;
182 if (!req_has_async_data(req))
183 return !io_req_prep_async(req);
184 iov_iter_restore(&io->s.iter, &io->s.iter_state);
188 static bool io_rw_should_reissue(struct io_kiocb *req)
190 umode_t mode = file_inode(req->file)->i_mode;
191 struct io_ring_ctx *ctx = req->ctx;
193 if (!S_ISBLK(mode) && !S_ISREG(mode))
195 if ((req->flags & REQ_F_NOWAIT) || (io_wq_current_is_worker() &&
196 !(ctx->flags & IORING_SETUP_IOPOLL)))
199 * If ref is dying, we might be running poll reap from the exit work.
200 * Don't attempt to reissue from that path, just let it fail with
203 if (percpu_ref_is_dying(&ctx->refs))
206 * Play it safe and assume not safe to re-import and reissue if we're
207 * not in the original thread group (or in task context).
209 if (!same_thread_group(req->task, current) || !in_task())
214 static bool io_resubmit_prep(struct io_kiocb *req)
218 static bool io_rw_should_reissue(struct io_kiocb *req)
224 static void io_req_end_write(struct io_kiocb *req)
226 if (req->flags & REQ_F_ISREG) {
227 struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
229 kiocb_end_write(&rw->kiocb);
234 * Trigger the notifications after having done some IO, and finish the write
235 * accounting, if any.
237 static void io_req_io_end(struct io_kiocb *req)
239 struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
241 if (rw->kiocb.ki_flags & IOCB_WRITE) {
242 io_req_end_write(req);
243 fsnotify_modify(req->file);
245 fsnotify_access(req->file);
249 static bool __io_complete_rw_common(struct io_kiocb *req, long res)
251 if (unlikely(res != req->cqe.res)) {
252 if ((res == -EAGAIN || res == -EOPNOTSUPP) &&
253 io_rw_should_reissue(req)) {
255 * Reissue will start accounting again, finish the
259 req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO;
268 static inline int io_fixup_rw_res(struct io_kiocb *req, long res)
270 struct io_async_rw *io = req->async_data;
272 /* add previously done IO, if any */
273 if (req_has_async_data(req) && io->bytes_done > 0) {
275 res = io->bytes_done;
277 res += io->bytes_done;
282 void io_req_rw_complete(struct io_kiocb *req, struct io_tw_state *ts)
284 struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
285 struct kiocb *kiocb = &rw->kiocb;
287 if ((kiocb->ki_flags & IOCB_DIO_CALLER_COMP) && kiocb->dio_complete) {
288 long res = kiocb->dio_complete(rw->kiocb.private);
290 io_req_set_res(req, io_fixup_rw_res(req, res), 0);
295 if (req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)) {
296 unsigned issue_flags = ts->locked ? 0 : IO_URING_F_UNLOCKED;
298 req->cqe.flags |= io_put_kbuf(req, issue_flags);
300 io_req_task_complete(req, ts);
303 static void io_complete_rw(struct kiocb *kiocb, long res)
305 struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb);
306 struct io_kiocb *req = cmd_to_io_kiocb(rw);
308 if (!kiocb->dio_complete || !(kiocb->ki_flags & IOCB_DIO_CALLER_COMP)) {
309 if (__io_complete_rw_common(req, res))
311 io_req_set_res(req, io_fixup_rw_res(req, res), 0);
313 req->io_task_work.func = io_req_rw_complete;
314 __io_req_task_work_add(req, IOU_F_TWQ_LAZY_WAKE);
317 static void io_complete_rw_iopoll(struct kiocb *kiocb, long res)
319 struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb);
320 struct io_kiocb *req = cmd_to_io_kiocb(rw);
322 if (kiocb->ki_flags & IOCB_WRITE)
323 io_req_end_write(req);
324 if (unlikely(res != req->cqe.res)) {
325 if (res == -EAGAIN && io_rw_should_reissue(req)) {
326 req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO;
332 /* order with io_iopoll_complete() checking ->iopoll_completed */
333 smp_store_release(&req->iopoll_completed, 1);
336 static int kiocb_done(struct io_kiocb *req, ssize_t ret,
337 unsigned int issue_flags)
339 struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
340 unsigned final_ret = io_fixup_rw_res(req, ret);
342 if (ret >= 0 && req->flags & REQ_F_CUR_POS)
343 req->file->f_pos = rw->kiocb.ki_pos;
344 if (ret >= 0 && (rw->kiocb.ki_complete == io_complete_rw)) {
345 if (!__io_complete_rw_common(req, ret)) {
347 * Safe to call io_end from here as we're inline
348 * from the submission path.
351 io_req_set_res(req, final_ret,
352 io_put_kbuf(req, issue_flags));
356 io_rw_done(&rw->kiocb, ret);
359 if (req->flags & REQ_F_REISSUE) {
360 req->flags &= ~REQ_F_REISSUE;
361 if (io_resubmit_prep(req))
362 io_req_task_queue_reissue(req);
364 io_req_task_queue_fail(req, final_ret);
366 return IOU_ISSUE_SKIP_COMPLETE;
369 static struct iovec *__io_import_iovec(int ddir, struct io_kiocb *req,
370 struct io_rw_state *s,
371 unsigned int issue_flags)
373 struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
374 struct iov_iter *iter = &s->iter;
375 u8 opcode = req->opcode;
381 if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
382 ret = io_import_fixed(ddir, iter, req->imu, rw->addr, rw->len);
388 buf = u64_to_user_ptr(rw->addr);
391 if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE ||
392 (req->flags & REQ_F_BUFFER_SELECT)) {
393 if (io_do_buffer_select(req)) {
394 buf = io_buffer_select(req, &sqe_len, issue_flags);
396 return ERR_PTR(-ENOBUFS);
397 rw->addr = (unsigned long) buf;
401 ret = import_ubuf(ddir, buf, sqe_len, iter);
408 ret = __import_iovec(ddir, buf, sqe_len, UIO_FASTIOV, &iovec, iter,
410 if (unlikely(ret < 0))
415 static inline int io_import_iovec(int rw, struct io_kiocb *req,
416 struct iovec **iovec, struct io_rw_state *s,
417 unsigned int issue_flags)
419 *iovec = __io_import_iovec(rw, req, s, issue_flags);
421 return PTR_ERR(*iovec);
423 iov_iter_save_state(&s->iter, &s->iter_state);
427 static inline loff_t *io_kiocb_ppos(struct kiocb *kiocb)
429 return (kiocb->ki_filp->f_mode & FMODE_STREAM) ? NULL : &kiocb->ki_pos;
433 * For files that don't have ->read_iter() and ->write_iter(), handle them
434 * by looping over ->read() or ->write() manually.
436 static ssize_t loop_rw_iter(int ddir, struct io_rw *rw, struct iov_iter *iter)
438 struct kiocb *kiocb = &rw->kiocb;
439 struct file *file = kiocb->ki_filp;
444 * Don't support polled IO through this interface, and we can't
445 * support non-blocking either. For the latter, this just causes
446 * the kiocb to be handled from an async context.
448 if (kiocb->ki_flags & IOCB_HIPRI)
450 if ((kiocb->ki_flags & IOCB_NOWAIT) &&
451 !(kiocb->ki_filp->f_flags & O_NONBLOCK))
454 ppos = io_kiocb_ppos(kiocb);
456 while (iov_iter_count(iter)) {
461 if (iter_is_ubuf(iter)) {
462 addr = iter->ubuf + iter->iov_offset;
463 len = iov_iter_count(iter);
464 } else if (!iov_iter_is_bvec(iter)) {
465 addr = iter_iov_addr(iter);
466 len = iter_iov_len(iter);
468 addr = u64_to_user_ptr(rw->addr);
473 nr = file->f_op->read(file, addr, len, ppos);
475 nr = file->f_op->write(file, addr, len, ppos);
483 if (!iov_iter_is_bvec(iter)) {
484 iov_iter_advance(iter, nr);
498 static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec,
499 const struct iovec *fast_iov, struct iov_iter *iter)
501 struct io_async_rw *io = req->async_data;
503 memcpy(&io->s.iter, iter, sizeof(*iter));
504 io->free_iovec = iovec;
506 /* can only be fixed buffers, no need to do anything */
507 if (iov_iter_is_bvec(iter) || iter_is_ubuf(iter))
510 unsigned iov_off = 0;
512 io->s.iter.__iov = io->s.fast_iov;
513 if (iter->__iov != fast_iov) {
514 iov_off = iter_iov(iter) - fast_iov;
515 io->s.iter.__iov += iov_off;
517 if (io->s.fast_iov != fast_iov)
518 memcpy(io->s.fast_iov + iov_off, fast_iov + iov_off,
519 sizeof(struct iovec) * iter->nr_segs);
521 req->flags |= REQ_F_NEED_CLEANUP;
525 static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec,
526 struct io_rw_state *s, bool force)
528 if (!force && !io_cold_defs[req->opcode].prep_async)
530 if (!req_has_async_data(req)) {
531 struct io_async_rw *iorw;
533 if (io_alloc_async_data(req)) {
538 io_req_map_rw(req, iovec, s->fast_iov, &s->iter);
539 iorw = req->async_data;
540 /* we've copied and mapped the iter, ensure state is saved */
541 iov_iter_save_state(&iorw->s.iter, &iorw->s.iter_state);
546 static inline int io_rw_prep_async(struct io_kiocb *req, int rw)
548 struct io_async_rw *iorw = req->async_data;
552 iorw->bytes_done = 0;
553 iorw->free_iovec = NULL;
555 /* submission path, ->uring_lock should already be taken */
556 ret = io_import_iovec(rw, req, &iov, &iorw->s, 0);
557 if (unlikely(ret < 0))
561 iorw->free_iovec = iov;
562 req->flags |= REQ_F_NEED_CLEANUP;
568 int io_readv_prep_async(struct io_kiocb *req)
570 return io_rw_prep_async(req, ITER_DEST);
573 int io_writev_prep_async(struct io_kiocb *req)
575 return io_rw_prep_async(req, ITER_SOURCE);
579 * This is our waitqueue callback handler, registered through __folio_lock_async()
580 * when we initially tried to do the IO with the iocb armed our waitqueue.
581 * This gets called when the page is unlocked, and we generally expect that to
582 * happen when the page IO is completed and the page is now uptodate. This will
583 * queue a task_work based retry of the operation, attempting to copy the data
584 * again. If the latter fails because the page was NOT uptodate, then we will
585 * do a thread based blocking retry of the operation. That's the unexpected
588 static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode,
591 struct wait_page_queue *wpq;
592 struct io_kiocb *req = wait->private;
593 struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
594 struct wait_page_key *key = arg;
596 wpq = container_of(wait, struct wait_page_queue, wait);
598 if (!wake_page_match(wpq, key))
601 rw->kiocb.ki_flags &= ~IOCB_WAITQ;
602 list_del_init(&wait->entry);
603 io_req_task_queue(req);
608 * This controls whether a given IO request should be armed for async page
609 * based retry. If we return false here, the request is handed to the async
610 * worker threads for retry. If we're doing buffered reads on a regular file,
611 * we prepare a private wait_page_queue entry and retry the operation. This
612 * will either succeed because the page is now uptodate and unlocked, or it
613 * will register a callback when the page is unlocked at IO completion. Through
614 * that callback, io_uring uses task_work to setup a retry of the operation.
615 * That retry will attempt the buffered read again. The retry will generally
616 * succeed, or in rare cases where it fails, we then fall back to using the
617 * async worker threads for a blocking retry.
619 static bool io_rw_should_retry(struct io_kiocb *req)
621 struct io_async_rw *io = req->async_data;
622 struct wait_page_queue *wait = &io->wpq;
623 struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
624 struct kiocb *kiocb = &rw->kiocb;
626 /* never retry for NOWAIT, we just complete with -EAGAIN */
627 if (req->flags & REQ_F_NOWAIT)
630 /* Only for buffered IO */
631 if (kiocb->ki_flags & (IOCB_DIRECT | IOCB_HIPRI))
635 * just use poll if we can, and don't attempt if the fs doesn't
636 * support callback based unlocks
638 if (file_can_poll(req->file) || !(req->file->f_mode & FMODE_BUF_RASYNC))
641 wait->wait.func = io_async_buf_func;
642 wait->wait.private = req;
643 wait->wait.flags = 0;
644 INIT_LIST_HEAD(&wait->wait.entry);
645 kiocb->ki_flags |= IOCB_WAITQ;
646 kiocb->ki_flags &= ~IOCB_NOWAIT;
647 kiocb->ki_waitq = wait;
651 static inline int io_iter_do_read(struct io_rw *rw, struct iov_iter *iter)
653 struct file *file = rw->kiocb.ki_filp;
655 if (likely(file->f_op->read_iter))
656 return call_read_iter(file, &rw->kiocb, iter);
657 else if (file->f_op->read)
658 return loop_rw_iter(READ, rw, iter);
663 static bool need_complete_io(struct io_kiocb *req)
665 return req->flags & REQ_F_ISREG ||
666 S_ISBLK(file_inode(req->file)->i_mode);
669 static int io_rw_init_file(struct io_kiocb *req, fmode_t mode)
671 struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
672 struct kiocb *kiocb = &rw->kiocb;
673 struct io_ring_ctx *ctx = req->ctx;
674 struct file *file = req->file;
677 if (unlikely(!file || !(file->f_mode & mode)))
680 if (!(req->flags & REQ_F_FIXED_FILE))
681 req->flags |= io_file_get_flags(file);
683 kiocb->ki_flags = file->f_iocb_flags;
684 ret = kiocb_set_rw_flags(kiocb, rw->flags);
687 kiocb->ki_flags |= IOCB_ALLOC_CACHE;
690 * If the file is marked O_NONBLOCK, still allow retry for it if it
691 * supports async. Otherwise it's impossible to use O_NONBLOCK files
692 * reliably. If not, or it IOCB_NOWAIT is set, don't retry.
694 if ((kiocb->ki_flags & IOCB_NOWAIT) ||
695 ((file->f_flags & O_NONBLOCK) && !io_file_supports_nowait(req)))
696 req->flags |= REQ_F_NOWAIT;
698 if (ctx->flags & IORING_SETUP_IOPOLL) {
699 if (!(kiocb->ki_flags & IOCB_DIRECT) || !file->f_op->iopoll)
702 kiocb->private = NULL;
703 kiocb->ki_flags |= IOCB_HIPRI;
704 kiocb->ki_complete = io_complete_rw_iopoll;
705 req->iopoll_completed = 0;
707 if (kiocb->ki_flags & IOCB_HIPRI)
709 kiocb->ki_complete = io_complete_rw;
715 int io_read(struct io_kiocb *req, unsigned int issue_flags)
717 struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
718 struct io_rw_state __s, *s = &__s;
720 struct kiocb *kiocb = &rw->kiocb;
721 bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
722 struct io_async_rw *io;
726 if (!req_has_async_data(req)) {
727 ret = io_import_iovec(ITER_DEST, req, &iovec, s, issue_flags);
728 if (unlikely(ret < 0))
731 io = req->async_data;
735 * Safe and required to re-import if we're using provided
736 * buffers, as we dropped the selected one before retry.
738 if (io_do_buffer_select(req)) {
739 ret = io_import_iovec(ITER_DEST, req, &iovec, s, issue_flags);
740 if (unlikely(ret < 0))
745 * We come here from an earlier attempt, restore our state to
746 * match in case it doesn't. It's cheap enough that we don't
747 * need to make this conditional.
749 iov_iter_restore(&s->iter, &s->iter_state);
752 ret = io_rw_init_file(req, FMODE_READ);
757 req->cqe.res = iov_iter_count(&s->iter);
759 if (force_nonblock) {
760 /* If the file doesn't support async, just async punt */
761 if (unlikely(!io_file_supports_nowait(req))) {
762 ret = io_setup_async_rw(req, iovec, s, true);
763 return ret ?: -EAGAIN;
765 kiocb->ki_flags |= IOCB_NOWAIT;
767 /* Ensure we clear previously set non-block flag */
768 kiocb->ki_flags &= ~IOCB_NOWAIT;
771 ppos = io_kiocb_update_pos(req);
773 ret = rw_verify_area(READ, req->file, ppos, req->cqe.res);
779 ret = io_iter_do_read(rw, &s->iter);
781 if (ret == -EAGAIN || (req->flags & REQ_F_REISSUE)) {
782 req->flags &= ~REQ_F_REISSUE;
783 /* if we can poll, just do that */
784 if (req->opcode == IORING_OP_READ && file_can_poll(req->file))
786 /* IOPOLL retry should happen for io-wq threads */
787 if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL))
789 /* no retry on NONBLOCK nor RWF_NOWAIT */
790 if (req->flags & REQ_F_NOWAIT)
793 } else if (ret == -EIOCBQUEUED) {
796 return IOU_ISSUE_SKIP_COMPLETE;
797 } else if (ret == req->cqe.res || ret <= 0 || !force_nonblock ||
798 (req->flags & REQ_F_NOWAIT) || !need_complete_io(req)) {
799 /* read all, failed, already did sync or don't want to retry */
804 * Don't depend on the iter state matching what was consumed, or being
805 * untouched in case of error. Restore it and we'll advance it
806 * manually if we need to.
808 iov_iter_restore(&s->iter, &s->iter_state);
810 ret2 = io_setup_async_rw(req, iovec, s, true);
813 ret = ret > 0 ? ret : ret2;
817 io = req->async_data;
820 * Now use our persistent iterator and state, if we aren't already.
821 * We've restored and mapped the iter to match.
826 * We end up here because of a partial read, either from
827 * above or inside this loop. Advance the iter by the bytes
828 * that were consumed.
830 iov_iter_advance(&s->iter, ret);
831 if (!iov_iter_count(&s->iter))
833 io->bytes_done += ret;
834 iov_iter_save_state(&s->iter, &s->iter_state);
836 /* if we can retry, do so with the callbacks armed */
837 if (!io_rw_should_retry(req)) {
838 kiocb->ki_flags &= ~IOCB_WAITQ;
842 req->cqe.res = iov_iter_count(&s->iter);
844 * Now retry read with the IOCB_WAITQ parts set in the iocb. If
845 * we get -EIOCBQUEUED, then we'll get a notification when the
846 * desired page gets unlocked. We can also get a partial read
847 * here, and if we do, then just retry at the new offset.
849 ret = io_iter_do_read(rw, &s->iter);
850 if (ret == -EIOCBQUEUED)
851 return IOU_ISSUE_SKIP_COMPLETE;
852 /* we got some bytes, but not all. retry. */
853 kiocb->ki_flags &= ~IOCB_WAITQ;
854 iov_iter_restore(&s->iter, &s->iter_state);
857 /* it's faster to check here then delegate to kfree */
860 return kiocb_done(req, ret, issue_flags);
863 int io_write(struct io_kiocb *req, unsigned int issue_flags)
865 struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
866 struct io_rw_state __s, *s = &__s;
868 struct kiocb *kiocb = &rw->kiocb;
869 bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
873 if (!req_has_async_data(req)) {
874 ret = io_import_iovec(ITER_SOURCE, req, &iovec, s, issue_flags);
875 if (unlikely(ret < 0))
878 struct io_async_rw *io = req->async_data;
881 iov_iter_restore(&s->iter, &s->iter_state);
884 ret = io_rw_init_file(req, FMODE_WRITE);
889 req->cqe.res = iov_iter_count(&s->iter);
891 if (force_nonblock) {
892 /* If the file doesn't support async, just async punt */
893 if (unlikely(!io_file_supports_nowait(req)))
896 /* File path supports NOWAIT for non-direct_IO only for block devices. */
897 if (!(kiocb->ki_flags & IOCB_DIRECT) &&
898 !(kiocb->ki_filp->f_mode & FMODE_BUF_WASYNC) &&
899 (req->flags & REQ_F_ISREG))
902 kiocb->ki_flags |= IOCB_NOWAIT;
904 /* Ensure we clear previously set non-block flag */
905 kiocb->ki_flags &= ~IOCB_NOWAIT;
908 ppos = io_kiocb_update_pos(req);
910 ret = rw_verify_area(WRITE, req->file, ppos, req->cqe.res);
916 if (req->flags & REQ_F_ISREG)
917 kiocb_start_write(kiocb);
918 kiocb->ki_flags |= IOCB_WRITE;
920 if (likely(req->file->f_op->write_iter))
921 ret2 = call_write_iter(req->file, kiocb, &s->iter);
922 else if (req->file->f_op->write)
923 ret2 = loop_rw_iter(WRITE, rw, &s->iter);
927 if (req->flags & REQ_F_REISSUE) {
928 req->flags &= ~REQ_F_REISSUE;
933 * Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just
934 * retry them without IOCB_NOWAIT.
936 if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT))
938 /* no retry on NONBLOCK nor RWF_NOWAIT */
939 if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT))
941 if (!force_nonblock || ret2 != -EAGAIN) {
942 /* IOPOLL retry should happen for io-wq threads */
943 if (ret2 == -EAGAIN && (req->ctx->flags & IORING_SETUP_IOPOLL))
946 if (ret2 != req->cqe.res && ret2 >= 0 && need_complete_io(req)) {
947 struct io_async_rw *io;
949 trace_io_uring_short_write(req->ctx, kiocb->ki_pos - ret2,
952 /* This is a partial write. The file pos has already been
953 * updated, setup the async struct to complete the request
954 * in the worker. Also update bytes_done to account for
955 * the bytes already written.
957 iov_iter_save_state(&s->iter, &s->iter_state);
958 ret = io_setup_async_rw(req, iovec, s, true);
960 io = req->async_data;
962 io->bytes_done += ret2;
964 if (kiocb->ki_flags & IOCB_WRITE)
965 io_req_end_write(req);
966 return ret ? ret : -EAGAIN;
969 ret = kiocb_done(req, ret2, issue_flags);
972 iov_iter_restore(&s->iter, &s->iter_state);
973 ret = io_setup_async_rw(req, iovec, s, false);
975 if (kiocb->ki_flags & IOCB_WRITE)
976 io_req_end_write(req);
981 /* it's reportedly faster than delegating the null check to kfree() */
987 void io_rw_fail(struct io_kiocb *req)
991 res = io_fixup_rw_res(req, req->cqe.res);
992 io_req_set_res(req, res, req->cqe.flags);
995 int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin)
997 struct io_wq_work_node *pos, *start, *prev;
998 unsigned int poll_flags = 0;
999 DEFINE_IO_COMP_BATCH(iob);
1003 * Only spin for completions if we don't have multiple devices hanging
1004 * off our complete list.
1006 if (ctx->poll_multi_queue || force_nonspin)
1007 poll_flags |= BLK_POLL_ONESHOT;
1009 wq_list_for_each(pos, start, &ctx->iopoll_list) {
1010 struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list);
1011 struct file *file = req->file;
1015 * Move completed and retryable entries to our local lists.
1016 * If we find a request that requires polling, break out
1017 * and complete those lists first, if we have entries there.
1019 if (READ_ONCE(req->iopoll_completed))
1022 if (req->opcode == IORING_OP_URING_CMD) {
1023 struct io_uring_cmd *ioucmd;
1025 ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
1026 ret = file->f_op->uring_cmd_iopoll(ioucmd, &iob,
1029 struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
1031 ret = file->f_op->iopoll(&rw->kiocb, &iob, poll_flags);
1033 if (unlikely(ret < 0))
1036 poll_flags |= BLK_POLL_ONESHOT;
1038 /* iopoll may have completed current req */
1039 if (!rq_list_empty(iob.req_list) ||
1040 READ_ONCE(req->iopoll_completed))
1044 if (!rq_list_empty(iob.req_list))
1050 wq_list_for_each_resume(pos, prev) {
1051 struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list);
1053 /* order with io_complete_rw_iopoll(), e.g. ->result updates */
1054 if (!smp_load_acquire(&req->iopoll_completed))
1057 req->cqe.flags = io_put_kbuf(req, 0);
1059 if (unlikely(!nr_events))
1062 pos = start ? start->next : ctx->iopoll_list.first;
1063 wq_list_cut(&ctx->iopoll_list, prev, start);
1065 if (WARN_ON_ONCE(!wq_list_empty(&ctx->submit_state.compl_reqs)))
1067 ctx->submit_state.compl_reqs.first = pos;
1068 __io_submit_flush_completions(ctx);