]> git.hungrycats.org Git - linux/commit
block: don't allow splitting of a REQ_NOWAIT bio
authorJens Axboe <axboe@kernel.dk>
Wed, 4 Jan 2023 15:52:06 +0000 (08:52 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 12 Jan 2023 11:00:46 +0000 (12:00 +0100)
commit3c09dbaf6ea1a027bfe31d6764be5012d21f297b
treecf387bb35c443bf8e2d782184cf648a34977b7cc
parent34a91a47e0794df64cfa928dc768acf5379452fb
block: don't allow splitting of a REQ_NOWAIT bio

commit 9cea62b2cbabff8ed46f2df17778b624ad9dd25a upstream.

If we split a bio marked with REQ_NOWAIT, then we can trigger spurious
EAGAIN if constituent parts of that split bio end up failing request
allocations. Parts will complete just fine, but just a single failure
in one of the chained bios will yield an EAGAIN final result for the
parent bio.

Return EAGAIN early if we end up needing to split such a bio, which
allows for saner recovery handling.

Cc: stable@vger.kernel.org # 5.15+
Link: https://github.com/axboe/liburing/issues/766
Reported-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
block/blk-merge.c