On 02/09/2020 19:00, Jens Axboe wrote:
> Actually two things that need fixing up here:
>
> - The io_rw_reissue() -EAGAIN retry is explicit to block devices and
> regular files, so don't ever attempt to do that on other types of
> files.
>
> - If we hit -EAGAIN on a nonblock marked file, don't arm poll handler for
> it. It should just complete with -EAGAIN.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Reported-by: Norman Maurer <norman.maurer@xxxxxxxxxxxxxx>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
>
> ---
>
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index b1ccd7072d93..65656102bbeb 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -2300,8 +2300,11 @@ static bool io_resubmit_prep(struct io_kiocb *req, int error)
> static bool io_rw_reissue(struct io_kiocb *req, long res)
> {
> #ifdef CONFIG_BLOCK
> + umode_t mode = file_inode(req->file)->i_mode;
> int ret;
>
> + if (!S_ISBLK(mode) && !S_ISREG(mode))
> + return false;
> if ((res != -EAGAIN && res != -EOPNOTSUPP) || io_wq_current_is_worker())
> return false;
>
> @@ -3146,6 +3149,9 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
> /* IOPOLL retry should happen for io-wq threads */
> if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL))
> goto done;
> + /* no retry on NONBLOCK marked file */
> + if (req->file->f_flags & O_NONBLOCK)
> + goto done;
Looks like it works with open(O_NONBLOCK) but not with IOCB_NOWAIT in the
request's flags. Is that so?
> /* some cases will consume bytes even on error returns */
> iov_iter_revert(iter, iov_count - iov_iter_count(iter));
> ret = io_setup_async_rw(req, iovec, inline_vecs, iter, false);
> @@ -3291,8 +3297,12 @@ static int io_write(struct io_kiocb *req, bool force_nonblock,
> /* IOPOLL retry should happen for io-wq threads */
> if ((req->ctx->flags & IORING_SETUP_IOPOLL) && ret2 == -EAGAIN)
> goto copy_iov;
> +done:
> kiocb_done(kiocb, ret2, cs);
> } else {
> + /* no retry on NONBLOCK marked file */
> + if (req->file->f_flags & O_NONBLOCK)
> + goto done;
> copy_iov:
> /* some cases will consume bytes even on error returns */
> iov_iter_revert(iter, iov_count - iov_iter_count(iter));
>
--
Pavel Begunkov
