Commit bba91cdb authored May 28, 2020 by Jens Axboe Committed by Greg Kroah-Hartman Jun 03, 2020

Revert "block: end bio with BLK_STS_AGAIN in case of non-mq devs and REQ_NOWAIT"



[ Upstream commit b0beb28097fa04177b3769f4bb7a0d0d9c4ae76e ]

This reverts commit c58c1f83436b501d45d4050fd1296d71a9760bcb.

io_uring does do the right thing for this case, and we're still returning
-EAGAIN to userspace for the cases we don't support. Revert this change
to avoid doing endless spins of resubmits.

Cc: stable@vger.kernel.org # v5.6
Reported-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 31f0b78b

block/blk-core.c

+4 −7

Original line number	Diff line number	Diff line
		@@ -886,14 +886,11 @@ generic_make_request_checks(struct bio *bio)
		}

		/*
		* Non-mq queues do not honor REQ_NOWAIT, so complete a bio
		* with BLK_STS_AGAIN status in order to catch -EAGAIN and
		* to give a chance to the caller to repeat request gracefully.
		* For a REQ_NOWAIT based request, return -EOPNOTSUPP
		* if queue is not a request based queue.
		*/
		if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_mq(q)) {
		status = BLK_STS_AGAIN;
		goto end_io;
		}
		if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_mq(q))
		goto not_supported;

		if (should_fail_bio(bio))
		goto end_io;