diff options
| author | Jens Axboe <axboe@kernel.dk> | 2021-09-14 11:08:37 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-09-14 11:09:42 -0600 |
| commit | 5d329e1286b0a040264e239b80257c937f6e685f (patch) | |
| tree | 0be1a797a2fe040abdcd2afdee057ea38f39ea08 /fs | |
| parent | 9c7b0ba887513b6681e7883d306df0a0fd580afa (diff) | |
| download | linux-5d329e1286b0a040264e239b80257c937f6e685f.tar.bz2 | |
io_uring: allow retry for O_NONBLOCK if async is supported
A common complaint is that using O_NONBLOCK files with io_uring can be a
bit of a pain. Be a bit nicer and allow normal retry IFF the file does
support async behavior. This makes it possible to use io_uring more
reliably with O_NONBLOCK files, for use cases where it either isn't
possible or feasible to modify the file flags.
Cc: stable@vger.kernel.org
Reported-and-tested-by: Dan Melnic <dmm@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/io_uring.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index ae489ab275dd..3077f85a2638 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2843,7 +2843,8 @@ static bool io_file_supports_nowait(struct io_kiocb *req, int rw) return __io_file_supports_nowait(req->file, rw); } -static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe) +static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, + int rw) { struct io_ring_ctx *ctx = req->ctx; struct kiocb *kiocb = &req->rw.kiocb; @@ -2865,8 +2866,13 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe) if (unlikely(ret)) return ret; - /* don't allow async punt for O_NONBLOCK or RWF_NOWAIT */ - if ((kiocb->ki_flags & IOCB_NOWAIT) || (file->f_flags & O_NONBLOCK)) + /* + * 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, rw))) req->flags |= REQ_F_NOWAIT; ioprio = READ_ONCE(sqe->ioprio); @@ -3349,7 +3355,7 @@ static int io_read_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (unlikely(!(req->file->f_mode & FMODE_READ))) return -EBADF; - return io_prep_rw(req, sqe); + return io_prep_rw(req, sqe, READ); } /* @@ -3542,7 +3548,7 @@ static int io_write_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (unlikely(!(req->file->f_mode & FMODE_WRITE))) return -EBADF; - return io_prep_rw(req, sqe); + return io_prep_rw(req, sqe, WRITE); } static int io_write(struct io_kiocb *req, unsigned int issue_flags) |