io_uring: maintain CQE order of a failed link

Arguably we want CQEs of linked requests be in a strict order of
submission as it always was. Now if init of a request fails its CQE may
be posted before all prior linked requests including the head of the
link. Fix it by failing it last.

Fixes: de59bc104c ("io_uring: fail links more in io_submit_sqe()")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b7a96b05832e7ab23ad55f84092a2548c4a888b0.1616699075.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2021-03-25 19:05:14 +00:00 committed by Jens Axboe
parent f5d2d23bf0
commit 90b8749022

View File

@ -6480,8 +6480,6 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
ret = io_init_req(ctx, req, sqe);
if (unlikely(ret)) {
fail_req:
io_put_req(req);
io_req_complete(req, ret);
if (link->head) {
/* fail even hard links since we don't submit */
link->head->flags |= REQ_F_FAIL_LINK;
@ -6489,6 +6487,8 @@ fail_req:
io_req_complete(link->head, -ECANCELED);
link->head = NULL;
}
io_put_req(req);
io_req_complete(req, ret);
return ret;
}
ret = io_req_prep(req, sqe);