mirror of
https://github.com/torvalds/linux.git
synced 2024-12-13 22:53:20 +00:00
2ec33a6c3c
A previous commit moved the notifications and end-write handling, but
it is now missing a few spots where we also want to call both of those.
Without that, we can potentially be missing file notifications, and
more importantly, have an imbalance in the super_block writers sem
accounting.
Fixes: b000145e99
("io_uring/rw: defer fsnotify calls to task context")
Reported-by: Dave Chinner <david@fromorbit.com>
Link: https://lore.kernel.org/all/20221010050319.GC2703033@dread.disaster.area/
Signed-off-by: Jens Axboe <axboe@kernel.dk>
1073 lines
27 KiB
C
1073 lines
27 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/blk-mq.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/fsnotify.h>
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#include <linux/poll.h>
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#include <linux/nospec.h>
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#include <linux/compat.h>
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#include <linux/io_uring.h>
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#include <uapi/linux/io_uring.h>
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#include "io_uring.h"
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#include "opdef.h"
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#include "kbuf.h"
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#include "rsrc.h"
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#include "rw.h"
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struct io_rw {
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/* NOTE: kiocb has the file as the first member, so don't do it here */
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struct kiocb kiocb;
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u64 addr;
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u32 len;
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rwf_t flags;
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};
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static inline bool io_file_supports_nowait(struct io_kiocb *req)
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{
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return req->flags & REQ_F_SUPPORT_NOWAIT;
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}
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#ifdef CONFIG_COMPAT
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static int io_iov_compat_buffer_select_prep(struct io_rw *rw)
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{
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struct compat_iovec __user *uiov;
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compat_ssize_t clen;
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uiov = u64_to_user_ptr(rw->addr);
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if (!access_ok(uiov, sizeof(*uiov)))
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return -EFAULT;
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if (__get_user(clen, &uiov->iov_len))
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return -EFAULT;
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if (clen < 0)
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return -EINVAL;
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rw->len = clen;
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return 0;
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}
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#endif
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static int io_iov_buffer_select_prep(struct io_kiocb *req)
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{
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struct iovec __user *uiov;
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struct iovec iov;
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struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
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if (rw->len != 1)
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return -EINVAL;
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#ifdef CONFIG_COMPAT
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if (req->ctx->compat)
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return io_iov_compat_buffer_select_prep(rw);
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#endif
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uiov = u64_to_user_ptr(rw->addr);
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if (copy_from_user(&iov, uiov, sizeof(*uiov)))
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return -EFAULT;
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rw->len = iov.iov_len;
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return 0;
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}
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int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
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{
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struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
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unsigned ioprio;
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int ret;
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rw->kiocb.ki_pos = READ_ONCE(sqe->off);
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/* used for fixed read/write too - just read unconditionally */
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req->buf_index = READ_ONCE(sqe->buf_index);
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if (req->opcode == IORING_OP_READ_FIXED ||
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req->opcode == IORING_OP_WRITE_FIXED) {
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struct io_ring_ctx *ctx = req->ctx;
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u16 index;
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if (unlikely(req->buf_index >= ctx->nr_user_bufs))
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return -EFAULT;
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index = array_index_nospec(req->buf_index, ctx->nr_user_bufs);
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req->imu = ctx->user_bufs[index];
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io_req_set_rsrc_node(req, ctx, 0);
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}
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ioprio = READ_ONCE(sqe->ioprio);
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if (ioprio) {
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ret = ioprio_check_cap(ioprio);
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if (ret)
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return ret;
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rw->kiocb.ki_ioprio = ioprio;
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} else {
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rw->kiocb.ki_ioprio = get_current_ioprio();
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}
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rw->addr = READ_ONCE(sqe->addr);
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rw->len = READ_ONCE(sqe->len);
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rw->flags = READ_ONCE(sqe->rw_flags);
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/* Have to do this validation here, as this is in io_read() rw->len might
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* have chanaged due to buffer selection
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*/
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if (req->opcode == IORING_OP_READV && req->flags & REQ_F_BUFFER_SELECT) {
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ret = io_iov_buffer_select_prep(req);
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if (ret)
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return ret;
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}
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return 0;
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}
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void io_readv_writev_cleanup(struct io_kiocb *req)
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{
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struct io_async_rw *io = req->async_data;
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kfree(io->free_iovec);
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}
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static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
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{
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switch (ret) {
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case -EIOCBQUEUED:
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break;
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case -ERESTARTSYS:
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case -ERESTARTNOINTR:
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case -ERESTARTNOHAND:
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case -ERESTART_RESTARTBLOCK:
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/*
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* We can't just restart the syscall, since previously
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* submitted sqes may already be in progress. Just fail this
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* IO with EINTR.
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*/
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ret = -EINTR;
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fallthrough;
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default:
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kiocb->ki_complete(kiocb, ret);
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}
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}
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static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req)
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{
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struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
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if (rw->kiocb.ki_pos != -1)
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return &rw->kiocb.ki_pos;
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if (!(req->file->f_mode & FMODE_STREAM)) {
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req->flags |= REQ_F_CUR_POS;
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rw->kiocb.ki_pos = req->file->f_pos;
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return &rw->kiocb.ki_pos;
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}
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rw->kiocb.ki_pos = 0;
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return NULL;
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}
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static void io_req_task_queue_reissue(struct io_kiocb *req)
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{
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req->io_task_work.func = io_queue_iowq;
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io_req_task_work_add(req);
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}
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#ifdef CONFIG_BLOCK
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static bool io_resubmit_prep(struct io_kiocb *req)
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{
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struct io_async_rw *io = req->async_data;
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if (!req_has_async_data(req))
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return !io_req_prep_async(req);
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iov_iter_restore(&io->s.iter, &io->s.iter_state);
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return true;
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}
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static bool io_rw_should_reissue(struct io_kiocb *req)
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{
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umode_t mode = file_inode(req->file)->i_mode;
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struct io_ring_ctx *ctx = req->ctx;
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if (!S_ISBLK(mode) && !S_ISREG(mode))
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return false;
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if ((req->flags & REQ_F_NOWAIT) || (io_wq_current_is_worker() &&
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!(ctx->flags & IORING_SETUP_IOPOLL)))
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return false;
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/*
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* If ref is dying, we might be running poll reap from the exit work.
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* Don't attempt to reissue from that path, just let it fail with
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* -EAGAIN.
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*/
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if (percpu_ref_is_dying(&ctx->refs))
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return false;
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/*
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* Play it safe and assume not safe to re-import and reissue if we're
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* not in the original thread group (or in task context).
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*/
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if (!same_thread_group(req->task, current) || !in_task())
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return false;
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return true;
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}
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#else
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static bool io_resubmit_prep(struct io_kiocb *req)
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{
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return false;
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}
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static bool io_rw_should_reissue(struct io_kiocb *req)
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{
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return false;
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}
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#endif
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static void kiocb_end_write(struct io_kiocb *req)
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{
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/*
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* Tell lockdep we inherited freeze protection from submission
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* thread.
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*/
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if (req->flags & REQ_F_ISREG) {
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struct super_block *sb = file_inode(req->file)->i_sb;
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__sb_writers_acquired(sb, SB_FREEZE_WRITE);
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sb_end_write(sb);
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}
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}
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/*
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* Trigger the notifications after having done some IO, and finish the write
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* accounting, if any.
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*/
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static void io_req_io_end(struct io_kiocb *req)
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{
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struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
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WARN_ON(!in_task());
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if (rw->kiocb.ki_flags & IOCB_WRITE) {
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kiocb_end_write(req);
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fsnotify_modify(req->file);
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} else {
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fsnotify_access(req->file);
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}
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}
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static bool __io_complete_rw_common(struct io_kiocb *req, long res)
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{
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if (unlikely(res != req->cqe.res)) {
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if ((res == -EAGAIN || res == -EOPNOTSUPP) &&
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io_rw_should_reissue(req)) {
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/*
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* Reissue will start accounting again, finish the
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* current cycle.
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*/
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io_req_io_end(req);
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req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO;
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return true;
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}
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req_set_fail(req);
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req->cqe.res = res;
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}
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return false;
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}
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static inline int io_fixup_rw_res(struct io_kiocb *req, long res)
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{
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struct io_async_rw *io = req->async_data;
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/* add previously done IO, if any */
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if (req_has_async_data(req) && io->bytes_done > 0) {
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if (res < 0)
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res = io->bytes_done;
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else
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res += io->bytes_done;
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}
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return res;
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}
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static void io_req_rw_complete(struct io_kiocb *req, bool *locked)
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{
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io_req_io_end(req);
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io_req_task_complete(req, locked);
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}
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static void io_complete_rw(struct kiocb *kiocb, long res)
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{
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struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb);
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struct io_kiocb *req = cmd_to_io_kiocb(rw);
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if (__io_complete_rw_common(req, res))
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return;
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io_req_set_res(req, io_fixup_rw_res(req, res), 0);
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req->io_task_work.func = io_req_rw_complete;
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io_req_task_work_add(req);
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}
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static void io_complete_rw_iopoll(struct kiocb *kiocb, long res)
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{
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struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb);
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struct io_kiocb *req = cmd_to_io_kiocb(rw);
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if (kiocb->ki_flags & IOCB_WRITE)
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kiocb_end_write(req);
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if (unlikely(res != req->cqe.res)) {
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if (res == -EAGAIN && io_rw_should_reissue(req)) {
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req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO;
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return;
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}
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req->cqe.res = res;
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}
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/* order with io_iopoll_complete() checking ->iopoll_completed */
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smp_store_release(&req->iopoll_completed, 1);
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}
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static int kiocb_done(struct io_kiocb *req, ssize_t ret,
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unsigned int issue_flags)
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{
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struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
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unsigned final_ret = io_fixup_rw_res(req, ret);
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if (req->flags & REQ_F_CUR_POS)
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req->file->f_pos = rw->kiocb.ki_pos;
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if (ret >= 0 && (rw->kiocb.ki_complete == io_complete_rw)) {
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if (!__io_complete_rw_common(req, ret)) {
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/*
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* Safe to call io_end from here as we're inline
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* from the submission path.
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*/
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io_req_io_end(req);
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io_req_set_res(req, final_ret,
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io_put_kbuf(req, issue_flags));
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return IOU_OK;
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}
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} else {
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io_rw_done(&rw->kiocb, ret);
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}
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if (req->flags & REQ_F_REISSUE) {
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req->flags &= ~REQ_F_REISSUE;
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if (io_resubmit_prep(req))
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io_req_task_queue_reissue(req);
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else
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io_req_task_queue_fail(req, final_ret);
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}
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return IOU_ISSUE_SKIP_COMPLETE;
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}
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static struct iovec *__io_import_iovec(int ddir, struct io_kiocb *req,
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struct io_rw_state *s,
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unsigned int issue_flags)
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{
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struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
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struct iov_iter *iter = &s->iter;
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u8 opcode = req->opcode;
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struct iovec *iovec;
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void __user *buf;
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size_t sqe_len;
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ssize_t ret;
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if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
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ret = io_import_fixed(ddir, iter, req->imu, rw->addr, rw->len);
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if (ret)
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return ERR_PTR(ret);
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return NULL;
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}
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buf = u64_to_user_ptr(rw->addr);
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sqe_len = rw->len;
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if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE ||
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(req->flags & REQ_F_BUFFER_SELECT)) {
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if (io_do_buffer_select(req)) {
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buf = io_buffer_select(req, &sqe_len, issue_flags);
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if (!buf)
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return ERR_PTR(-ENOBUFS);
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rw->addr = (unsigned long) buf;
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rw->len = sqe_len;
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}
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ret = import_single_range(ddir, buf, sqe_len, s->fast_iov, iter);
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if (ret)
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return ERR_PTR(ret);
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return NULL;
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}
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iovec = s->fast_iov;
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ret = __import_iovec(ddir, buf, sqe_len, UIO_FASTIOV, &iovec, iter,
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req->ctx->compat);
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if (unlikely(ret < 0))
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return ERR_PTR(ret);
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return iovec;
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}
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static inline int io_import_iovec(int rw, struct io_kiocb *req,
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struct iovec **iovec, struct io_rw_state *s,
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unsigned int issue_flags)
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{
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*iovec = __io_import_iovec(rw, req, s, issue_flags);
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if (unlikely(IS_ERR(*iovec)))
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return PTR_ERR(*iovec);
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iov_iter_save_state(&s->iter, &s->iter_state);
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return 0;
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}
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static inline loff_t *io_kiocb_ppos(struct kiocb *kiocb)
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{
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return (kiocb->ki_filp->f_mode & FMODE_STREAM) ? NULL : &kiocb->ki_pos;
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}
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/*
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* For files that don't have ->read_iter() and ->write_iter(), handle them
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* by looping over ->read() or ->write() manually.
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*/
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static ssize_t loop_rw_iter(int ddir, struct io_rw *rw, struct iov_iter *iter)
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{
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struct kiocb *kiocb = &rw->kiocb;
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struct file *file = kiocb->ki_filp;
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ssize_t ret = 0;
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loff_t *ppos;
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/*
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* Don't support polled IO through this interface, and we can't
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* support non-blocking either. For the latter, this just causes
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* the kiocb to be handled from an async context.
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*/
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if (kiocb->ki_flags & IOCB_HIPRI)
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return -EOPNOTSUPP;
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if ((kiocb->ki_flags & IOCB_NOWAIT) &&
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!(kiocb->ki_filp->f_flags & O_NONBLOCK))
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return -EAGAIN;
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ppos = io_kiocb_ppos(kiocb);
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while (iov_iter_count(iter)) {
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struct iovec iovec;
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ssize_t nr;
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if (!iov_iter_is_bvec(iter)) {
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iovec = iov_iter_iovec(iter);
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} else {
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iovec.iov_base = u64_to_user_ptr(rw->addr);
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iovec.iov_len = rw->len;
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}
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if (ddir == READ) {
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nr = file->f_op->read(file, iovec.iov_base,
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iovec.iov_len, ppos);
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} else {
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nr = file->f_op->write(file, iovec.iov_base,
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iovec.iov_len, ppos);
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}
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if (nr < 0) {
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if (!ret)
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ret = nr;
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break;
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}
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ret += nr;
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if (!iov_iter_is_bvec(iter)) {
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iov_iter_advance(iter, nr);
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} else {
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rw->addr += nr;
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rw->len -= nr;
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if (!rw->len)
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break;
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}
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if (nr != iovec.iov_len)
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break;
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}
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return ret;
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}
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static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec,
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const struct iovec *fast_iov, struct iov_iter *iter)
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{
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struct io_async_rw *io = req->async_data;
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|
|
memcpy(&io->s.iter, iter, sizeof(*iter));
|
|
io->free_iovec = iovec;
|
|
io->bytes_done = 0;
|
|
/* can only be fixed buffers, no need to do anything */
|
|
if (iov_iter_is_bvec(iter))
|
|
return;
|
|
if (!iovec) {
|
|
unsigned iov_off = 0;
|
|
|
|
io->s.iter.iov = io->s.fast_iov;
|
|
if (iter->iov != fast_iov) {
|
|
iov_off = iter->iov - fast_iov;
|
|
io->s.iter.iov += iov_off;
|
|
}
|
|
if (io->s.fast_iov != fast_iov)
|
|
memcpy(io->s.fast_iov + iov_off, fast_iov + iov_off,
|
|
sizeof(struct iovec) * iter->nr_segs);
|
|
} else {
|
|
req->flags |= REQ_F_NEED_CLEANUP;
|
|
}
|
|
}
|
|
|
|
static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec,
|
|
struct io_rw_state *s, bool force)
|
|
{
|
|
if (!force && !io_op_defs[req->opcode].prep_async)
|
|
return 0;
|
|
if (!req_has_async_data(req)) {
|
|
struct io_async_rw *iorw;
|
|
|
|
if (io_alloc_async_data(req)) {
|
|
kfree(iovec);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
io_req_map_rw(req, iovec, s->fast_iov, &s->iter);
|
|
iorw = req->async_data;
|
|
/* we've copied and mapped the iter, ensure state is saved */
|
|
iov_iter_save_state(&iorw->s.iter, &iorw->s.iter_state);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static inline int io_rw_prep_async(struct io_kiocb *req, int rw)
|
|
{
|
|
struct io_async_rw *iorw = req->async_data;
|
|
struct iovec *iov;
|
|
int ret;
|
|
|
|
/* submission path, ->uring_lock should already be taken */
|
|
ret = io_import_iovec(rw, req, &iov, &iorw->s, 0);
|
|
if (unlikely(ret < 0))
|
|
return ret;
|
|
|
|
iorw->bytes_done = 0;
|
|
iorw->free_iovec = iov;
|
|
if (iov)
|
|
req->flags |= REQ_F_NEED_CLEANUP;
|
|
return 0;
|
|
}
|
|
|
|
int io_readv_prep_async(struct io_kiocb *req)
|
|
{
|
|
return io_rw_prep_async(req, READ);
|
|
}
|
|
|
|
int io_writev_prep_async(struct io_kiocb *req)
|
|
{
|
|
return io_rw_prep_async(req, WRITE);
|
|
}
|
|
|
|
/*
|
|
* This is our waitqueue callback handler, registered through __folio_lock_async()
|
|
* when we initially tried to do the IO with the iocb armed our waitqueue.
|
|
* This gets called when the page is unlocked, and we generally expect that to
|
|
* happen when the page IO is completed and the page is now uptodate. This will
|
|
* queue a task_work based retry of the operation, attempting to copy the data
|
|
* again. If the latter fails because the page was NOT uptodate, then we will
|
|
* do a thread based blocking retry of the operation. That's the unexpected
|
|
* slow path.
|
|
*/
|
|
static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode,
|
|
int sync, void *arg)
|
|
{
|
|
struct wait_page_queue *wpq;
|
|
struct io_kiocb *req = wait->private;
|
|
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
|
|
struct wait_page_key *key = arg;
|
|
|
|
wpq = container_of(wait, struct wait_page_queue, wait);
|
|
|
|
if (!wake_page_match(wpq, key))
|
|
return 0;
|
|
|
|
rw->kiocb.ki_flags &= ~IOCB_WAITQ;
|
|
list_del_init(&wait->entry);
|
|
io_req_task_queue(req);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* This controls whether a given IO request should be armed for async page
|
|
* based retry. If we return false here, the request is handed to the async
|
|
* worker threads for retry. If we're doing buffered reads on a regular file,
|
|
* we prepare a private wait_page_queue entry and retry the operation. This
|
|
* will either succeed because the page is now uptodate and unlocked, or it
|
|
* will register a callback when the page is unlocked at IO completion. Through
|
|
* that callback, io_uring uses task_work to setup a retry of the operation.
|
|
* That retry will attempt the buffered read again. The retry will generally
|
|
* succeed, or in rare cases where it fails, we then fall back to using the
|
|
* async worker threads for a blocking retry.
|
|
*/
|
|
static bool io_rw_should_retry(struct io_kiocb *req)
|
|
{
|
|
struct io_async_rw *io = req->async_data;
|
|
struct wait_page_queue *wait = &io->wpq;
|
|
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
|
|
struct kiocb *kiocb = &rw->kiocb;
|
|
|
|
/* never retry for NOWAIT, we just complete with -EAGAIN */
|
|
if (req->flags & REQ_F_NOWAIT)
|
|
return false;
|
|
|
|
/* Only for buffered IO */
|
|
if (kiocb->ki_flags & (IOCB_DIRECT | IOCB_HIPRI))
|
|
return false;
|
|
|
|
/*
|
|
* just use poll if we can, and don't attempt if the fs doesn't
|
|
* support callback based unlocks
|
|
*/
|
|
if (file_can_poll(req->file) || !(req->file->f_mode & FMODE_BUF_RASYNC))
|
|
return false;
|
|
|
|
wait->wait.func = io_async_buf_func;
|
|
wait->wait.private = req;
|
|
wait->wait.flags = 0;
|
|
INIT_LIST_HEAD(&wait->wait.entry);
|
|
kiocb->ki_flags |= IOCB_WAITQ;
|
|
kiocb->ki_flags &= ~IOCB_NOWAIT;
|
|
kiocb->ki_waitq = wait;
|
|
return true;
|
|
}
|
|
|
|
static inline int io_iter_do_read(struct io_rw *rw, struct iov_iter *iter)
|
|
{
|
|
struct file *file = rw->kiocb.ki_filp;
|
|
|
|
if (likely(file->f_op->read_iter))
|
|
return call_read_iter(file, &rw->kiocb, iter);
|
|
else if (file->f_op->read)
|
|
return loop_rw_iter(READ, rw, iter);
|
|
else
|
|
return -EINVAL;
|
|
}
|
|
|
|
static bool need_complete_io(struct io_kiocb *req)
|
|
{
|
|
return req->flags & REQ_F_ISREG ||
|
|
S_ISBLK(file_inode(req->file)->i_mode);
|
|
}
|
|
|
|
static int io_rw_init_file(struct io_kiocb *req, fmode_t mode)
|
|
{
|
|
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
|
|
struct kiocb *kiocb = &rw->kiocb;
|
|
struct io_ring_ctx *ctx = req->ctx;
|
|
struct file *file = req->file;
|
|
int ret;
|
|
|
|
if (unlikely(!file || !(file->f_mode & mode)))
|
|
return -EBADF;
|
|
|
|
if (!io_req_ffs_set(req))
|
|
req->flags |= io_file_get_flags(file) << REQ_F_SUPPORT_NOWAIT_BIT;
|
|
|
|
kiocb->ki_flags = file->f_iocb_flags;
|
|
ret = kiocb_set_rw_flags(kiocb, rw->flags);
|
|
if (unlikely(ret))
|
|
return ret;
|
|
|
|
/*
|
|
* If the file is marked O_NONBLOCK, still allow retry for it if it
|
|
* supports async. Otherwise it's impossible to use O_NONBLOCK files
|
|
* reliably. If not, or it IOCB_NOWAIT is set, don't retry.
|
|
*/
|
|
if ((kiocb->ki_flags & IOCB_NOWAIT) ||
|
|
((file->f_flags & O_NONBLOCK) && !io_file_supports_nowait(req)))
|
|
req->flags |= REQ_F_NOWAIT;
|
|
|
|
if (ctx->flags & IORING_SETUP_IOPOLL) {
|
|
if (!(kiocb->ki_flags & IOCB_DIRECT) || !file->f_op->iopoll)
|
|
return -EOPNOTSUPP;
|
|
|
|
kiocb->private = NULL;
|
|
kiocb->ki_flags |= IOCB_HIPRI | IOCB_ALLOC_CACHE;
|
|
kiocb->ki_complete = io_complete_rw_iopoll;
|
|
req->iopoll_completed = 0;
|
|
} else {
|
|
if (kiocb->ki_flags & IOCB_HIPRI)
|
|
return -EINVAL;
|
|
kiocb->ki_complete = io_complete_rw;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int io_read(struct io_kiocb *req, unsigned int issue_flags)
|
|
{
|
|
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
|
|
struct io_rw_state __s, *s = &__s;
|
|
struct iovec *iovec;
|
|
struct kiocb *kiocb = &rw->kiocb;
|
|
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
|
|
struct io_async_rw *io;
|
|
ssize_t ret, ret2;
|
|
loff_t *ppos;
|
|
|
|
if (!req_has_async_data(req)) {
|
|
ret = io_import_iovec(READ, req, &iovec, s, issue_flags);
|
|
if (unlikely(ret < 0))
|
|
return ret;
|
|
} else {
|
|
io = req->async_data;
|
|
s = &io->s;
|
|
|
|
/*
|
|
* Safe and required to re-import if we're using provided
|
|
* buffers, as we dropped the selected one before retry.
|
|
*/
|
|
if (io_do_buffer_select(req)) {
|
|
ret = io_import_iovec(READ, req, &iovec, s, issue_flags);
|
|
if (unlikely(ret < 0))
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* We come here from an earlier attempt, restore our state to
|
|
* match in case it doesn't. It's cheap enough that we don't
|
|
* need to make this conditional.
|
|
*/
|
|
iov_iter_restore(&s->iter, &s->iter_state);
|
|
iovec = NULL;
|
|
}
|
|
ret = io_rw_init_file(req, FMODE_READ);
|
|
if (unlikely(ret)) {
|
|
kfree(iovec);
|
|
return ret;
|
|
}
|
|
req->cqe.res = iov_iter_count(&s->iter);
|
|
|
|
if (force_nonblock) {
|
|
/* If the file doesn't support async, just async punt */
|
|
if (unlikely(!io_file_supports_nowait(req))) {
|
|
ret = io_setup_async_rw(req, iovec, s, true);
|
|
return ret ?: -EAGAIN;
|
|
}
|
|
kiocb->ki_flags |= IOCB_NOWAIT;
|
|
} else {
|
|
/* Ensure we clear previously set non-block flag */
|
|
kiocb->ki_flags &= ~IOCB_NOWAIT;
|
|
}
|
|
|
|
ppos = io_kiocb_update_pos(req);
|
|
|
|
ret = rw_verify_area(READ, req->file, ppos, req->cqe.res);
|
|
if (unlikely(ret)) {
|
|
kfree(iovec);
|
|
return ret;
|
|
}
|
|
|
|
ret = io_iter_do_read(rw, &s->iter);
|
|
|
|
if (ret == -EAGAIN || (req->flags & REQ_F_REISSUE)) {
|
|
req->flags &= ~REQ_F_REISSUE;
|
|
/* if we can poll, just do that */
|
|
if (req->opcode == IORING_OP_READ && file_can_poll(req->file))
|
|
return -EAGAIN;
|
|
/* IOPOLL retry should happen for io-wq threads */
|
|
if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL))
|
|
goto done;
|
|
/* no retry on NONBLOCK nor RWF_NOWAIT */
|
|
if (req->flags & REQ_F_NOWAIT)
|
|
goto done;
|
|
ret = 0;
|
|
} else if (ret == -EIOCBQUEUED) {
|
|
if (iovec)
|
|
kfree(iovec);
|
|
return IOU_ISSUE_SKIP_COMPLETE;
|
|
} else if (ret == req->cqe.res || ret <= 0 || !force_nonblock ||
|
|
(req->flags & REQ_F_NOWAIT) || !need_complete_io(req)) {
|
|
/* read all, failed, already did sync or don't want to retry */
|
|
goto done;
|
|
}
|
|
|
|
/*
|
|
* Don't depend on the iter state matching what was consumed, or being
|
|
* untouched in case of error. Restore it and we'll advance it
|
|
* manually if we need to.
|
|
*/
|
|
iov_iter_restore(&s->iter, &s->iter_state);
|
|
|
|
ret2 = io_setup_async_rw(req, iovec, s, true);
|
|
iovec = NULL;
|
|
if (ret2) {
|
|
ret = ret > 0 ? ret : ret2;
|
|
goto done;
|
|
}
|
|
|
|
io = req->async_data;
|
|
s = &io->s;
|
|
/*
|
|
* Now use our persistent iterator and state, if we aren't already.
|
|
* We've restored and mapped the iter to match.
|
|
*/
|
|
|
|
do {
|
|
/*
|
|
* We end up here because of a partial read, either from
|
|
* above or inside this loop. Advance the iter by the bytes
|
|
* that were consumed.
|
|
*/
|
|
iov_iter_advance(&s->iter, ret);
|
|
if (!iov_iter_count(&s->iter))
|
|
break;
|
|
io->bytes_done += ret;
|
|
iov_iter_save_state(&s->iter, &s->iter_state);
|
|
|
|
/* if we can retry, do so with the callbacks armed */
|
|
if (!io_rw_should_retry(req)) {
|
|
kiocb->ki_flags &= ~IOCB_WAITQ;
|
|
return -EAGAIN;
|
|
}
|
|
|
|
req->cqe.res = iov_iter_count(&s->iter);
|
|
/*
|
|
* Now retry read with the IOCB_WAITQ parts set in the iocb. If
|
|
* we get -EIOCBQUEUED, then we'll get a notification when the
|
|
* desired page gets unlocked. We can also get a partial read
|
|
* here, and if we do, then just retry at the new offset.
|
|
*/
|
|
ret = io_iter_do_read(rw, &s->iter);
|
|
if (ret == -EIOCBQUEUED)
|
|
return IOU_ISSUE_SKIP_COMPLETE;
|
|
/* we got some bytes, but not all. retry. */
|
|
kiocb->ki_flags &= ~IOCB_WAITQ;
|
|
iov_iter_restore(&s->iter, &s->iter_state);
|
|
} while (ret > 0);
|
|
done:
|
|
/* it's faster to check here then delegate to kfree */
|
|
if (iovec)
|
|
kfree(iovec);
|
|
return kiocb_done(req, ret, issue_flags);
|
|
}
|
|
|
|
int io_write(struct io_kiocb *req, unsigned int issue_flags)
|
|
{
|
|
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
|
|
struct io_rw_state __s, *s = &__s;
|
|
struct iovec *iovec;
|
|
struct kiocb *kiocb = &rw->kiocb;
|
|
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
|
|
ssize_t ret, ret2;
|
|
loff_t *ppos;
|
|
|
|
if (!req_has_async_data(req)) {
|
|
ret = io_import_iovec(WRITE, req, &iovec, s, issue_flags);
|
|
if (unlikely(ret < 0))
|
|
return ret;
|
|
} else {
|
|
struct io_async_rw *io = req->async_data;
|
|
|
|
s = &io->s;
|
|
iov_iter_restore(&s->iter, &s->iter_state);
|
|
iovec = NULL;
|
|
}
|
|
ret = io_rw_init_file(req, FMODE_WRITE);
|
|
if (unlikely(ret)) {
|
|
kfree(iovec);
|
|
return ret;
|
|
}
|
|
req->cqe.res = iov_iter_count(&s->iter);
|
|
|
|
if (force_nonblock) {
|
|
/* If the file doesn't support async, just async punt */
|
|
if (unlikely(!io_file_supports_nowait(req)))
|
|
goto copy_iov;
|
|
|
|
/* File path supports NOWAIT for non-direct_IO only for block devices. */
|
|
if (!(kiocb->ki_flags & IOCB_DIRECT) &&
|
|
!(kiocb->ki_filp->f_mode & FMODE_BUF_WASYNC) &&
|
|
(req->flags & REQ_F_ISREG))
|
|
goto copy_iov;
|
|
|
|
kiocb->ki_flags |= IOCB_NOWAIT;
|
|
} else {
|
|
/* Ensure we clear previously set non-block flag */
|
|
kiocb->ki_flags &= ~IOCB_NOWAIT;
|
|
}
|
|
|
|
ppos = io_kiocb_update_pos(req);
|
|
|
|
ret = rw_verify_area(WRITE, req->file, ppos, req->cqe.res);
|
|
if (unlikely(ret)) {
|
|
kfree(iovec);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Open-code file_start_write here to grab freeze protection,
|
|
* which will be released by another thread in
|
|
* io_complete_rw(). Fool lockdep by telling it the lock got
|
|
* released so that it doesn't complain about the held lock when
|
|
* we return to userspace.
|
|
*/
|
|
if (req->flags & REQ_F_ISREG) {
|
|
sb_start_write(file_inode(req->file)->i_sb);
|
|
__sb_writers_release(file_inode(req->file)->i_sb,
|
|
SB_FREEZE_WRITE);
|
|
}
|
|
kiocb->ki_flags |= IOCB_WRITE;
|
|
|
|
if (likely(req->file->f_op->write_iter))
|
|
ret2 = call_write_iter(req->file, kiocb, &s->iter);
|
|
else if (req->file->f_op->write)
|
|
ret2 = loop_rw_iter(WRITE, rw, &s->iter);
|
|
else
|
|
ret2 = -EINVAL;
|
|
|
|
if (req->flags & REQ_F_REISSUE) {
|
|
req->flags &= ~REQ_F_REISSUE;
|
|
ret2 = -EAGAIN;
|
|
}
|
|
|
|
/*
|
|
* Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just
|
|
* retry them without IOCB_NOWAIT.
|
|
*/
|
|
if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT))
|
|
ret2 = -EAGAIN;
|
|
/* no retry on NONBLOCK nor RWF_NOWAIT */
|
|
if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT))
|
|
goto done;
|
|
if (!force_nonblock || ret2 != -EAGAIN) {
|
|
/* IOPOLL retry should happen for io-wq threads */
|
|
if (ret2 == -EAGAIN && (req->ctx->flags & IORING_SETUP_IOPOLL))
|
|
goto copy_iov;
|
|
|
|
if (ret2 != req->cqe.res && ret2 >= 0 && need_complete_io(req)) {
|
|
struct io_async_rw *io;
|
|
|
|
trace_io_uring_short_write(req->ctx, kiocb->ki_pos - ret2,
|
|
req->cqe.res, ret2);
|
|
|
|
/* This is a partial write. The file pos has already been
|
|
* updated, setup the async struct to complete the request
|
|
* in the worker. Also update bytes_done to account for
|
|
* the bytes already written.
|
|
*/
|
|
iov_iter_save_state(&s->iter, &s->iter_state);
|
|
ret = io_setup_async_rw(req, iovec, s, true);
|
|
|
|
io = req->async_data;
|
|
if (io)
|
|
io->bytes_done += ret2;
|
|
|
|
if (kiocb->ki_flags & IOCB_WRITE)
|
|
kiocb_end_write(req);
|
|
return ret ? ret : -EAGAIN;
|
|
}
|
|
done:
|
|
ret = kiocb_done(req, ret2, issue_flags);
|
|
} else {
|
|
copy_iov:
|
|
iov_iter_restore(&s->iter, &s->iter_state);
|
|
ret = io_setup_async_rw(req, iovec, s, false);
|
|
if (!ret) {
|
|
if (kiocb->ki_flags & IOCB_WRITE)
|
|
kiocb_end_write(req);
|
|
return -EAGAIN;
|
|
}
|
|
return ret;
|
|
}
|
|
/* it's reportedly faster than delegating the null check to kfree() */
|
|
if (iovec)
|
|
kfree(iovec);
|
|
return ret;
|
|
}
|
|
|
|
static void io_cqring_ev_posted_iopoll(struct io_ring_ctx *ctx)
|
|
{
|
|
io_commit_cqring_flush(ctx);
|
|
if (ctx->flags & IORING_SETUP_SQPOLL)
|
|
io_cqring_wake(ctx);
|
|
}
|
|
|
|
void io_rw_fail(struct io_kiocb *req)
|
|
{
|
|
int res;
|
|
|
|
res = io_fixup_rw_res(req, req->cqe.res);
|
|
io_req_set_res(req, res, req->cqe.flags);
|
|
}
|
|
|
|
int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin)
|
|
{
|
|
struct io_wq_work_node *pos, *start, *prev;
|
|
unsigned int poll_flags = BLK_POLL_NOSLEEP;
|
|
DEFINE_IO_COMP_BATCH(iob);
|
|
int nr_events = 0;
|
|
|
|
/*
|
|
* Only spin for completions if we don't have multiple devices hanging
|
|
* off our complete list.
|
|
*/
|
|
if (ctx->poll_multi_queue || force_nonspin)
|
|
poll_flags |= BLK_POLL_ONESHOT;
|
|
|
|
wq_list_for_each(pos, start, &ctx->iopoll_list) {
|
|
struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list);
|
|
struct file *file = req->file;
|
|
int ret;
|
|
|
|
/*
|
|
* Move completed and retryable entries to our local lists.
|
|
* If we find a request that requires polling, break out
|
|
* and complete those lists first, if we have entries there.
|
|
*/
|
|
if (READ_ONCE(req->iopoll_completed))
|
|
break;
|
|
|
|
if (req->opcode == IORING_OP_URING_CMD) {
|
|
struct io_uring_cmd *ioucmd;
|
|
|
|
ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
|
|
ret = file->f_op->uring_cmd_iopoll(ioucmd, &iob,
|
|
poll_flags);
|
|
} else {
|
|
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
|
|
|
|
ret = file->f_op->iopoll(&rw->kiocb, &iob, poll_flags);
|
|
}
|
|
if (unlikely(ret < 0))
|
|
return ret;
|
|
else if (ret)
|
|
poll_flags |= BLK_POLL_ONESHOT;
|
|
|
|
/* iopoll may have completed current req */
|
|
if (!rq_list_empty(iob.req_list) ||
|
|
READ_ONCE(req->iopoll_completed))
|
|
break;
|
|
}
|
|
|
|
if (!rq_list_empty(iob.req_list))
|
|
iob.complete(&iob);
|
|
else if (!pos)
|
|
return 0;
|
|
|
|
prev = start;
|
|
wq_list_for_each_resume(pos, prev) {
|
|
struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list);
|
|
|
|
/* order with io_complete_rw_iopoll(), e.g. ->result updates */
|
|
if (!smp_load_acquire(&req->iopoll_completed))
|
|
break;
|
|
nr_events++;
|
|
if (unlikely(req->flags & REQ_F_CQE_SKIP))
|
|
continue;
|
|
|
|
req->cqe.flags = io_put_kbuf(req, 0);
|
|
__io_fill_cqe_req(req->ctx, req);
|
|
}
|
|
|
|
if (unlikely(!nr_events))
|
|
return 0;
|
|
|
|
io_commit_cqring(ctx);
|
|
io_cqring_ev_posted_iopoll(ctx);
|
|
pos = start ? start->next : ctx->iopoll_list.first;
|
|
wq_list_cut(&ctx->iopoll_list, prev, start);
|
|
io_free_batch_list(ctx, pos);
|
|
return nr_events;
|
|
}
|