[focal:linux-bluefield][PATCH 0/1] UBUNTU: SAUCE: Revert "block: don't ignore REQ_NOWAIT for direct IO"

Wen-chien Jesse Sung jesse.sung at canonical.com
Wed Oct 6 11:06:42 UTC 2021

BugLink: https://launchpad.net/bugs/1946219

== Impact ==
After configuration multipath with io uring virtio_blk module is stuck

== Fix ==
The issue was introduced by one of the stable updates merged in the base
kernel Ubuntu-5.4.0-74.83. After reverting the commit the issue can not be
reproduced any more.

commit d6757b3e34831b7615edd3268b878536761f8b2e
Author: Pavel Begunkov <asml.silence at gmail.com>
Date: Fri Nov 20 17:10:28 2020 +0000

    block: don't ignore REQ_NOWAIT for direct IO

    BugLink: https://bugs.launchpad.net/bugs/1926490

    [ Upstream commit f8b78caf21d5bc3fcfc40c18898f9d52ed1451a5 ]

    If IOCB_NOWAIT is set on submission, then that needs to get propagated to
    REQ_NOWAIT on the block side. Otherwise we completely lose this
    information, and any issuer of IOCB_NOWAIT IO will potentially end up
    blocking on eg request allocation on the storage side.

    Signed-off-by: Pavel Begunkov <asml.silence at gmail.com>
    Signed-off-by: Jens Axboe <axboe at kernel.dk>
    Signed-off-by: Sasha Levin <sashal at kernel.org>
    Signed-off-by: Kamal Mostafa <kamal at canonical.com>
    Signed-off-by: Stefan Bader <stefan.bader at canonical.com>

== Risk of Regression ==
Medium. The commit has a good reason to be part of the stable updates. However
the kernel passes Cert and Nvidia tests without the commit so reverting the
commit should be an acceptable approach for now.

Wen-chien Jesse Sung (1):
  UBUNTU: SAUCE: Revert "block: don't ignore REQ_NOWAIT for direct IO"

 fs/block_dev.c | 4 ----
 1 file changed, 4 deletions(-)


More information about the kernel-team mailing list