tree d3cdbfaa7aecbe941417bc63435b1f315aabf762
parent 9e6a57d2cdee36a6d9c5d5cc3db85713dd416719
author Thorsten Knabe <linux@thorsten-knabe.de> 1408801658 +0200
committer Richard Weinberger <richard@nod.at> 1413229555 +0200

um: ubd: Fix for processes stuck in D state forever

Starting with Linux 3.12 processes get stuck in D state forever in
UserModeLinux under sync heavy workloads. This bug was introduced by
commit 805f11a0d5 (um: ubd: Add REQ_FLUSH suppport).
Fix bug by adding a check if FLUSH request was successfully submitted to
the I/O thread and keeping the FLUSH request on the request queue on
submission failures.

Fixes: 805f11a0d5 (um: ubd: Add REQ_FLUSH suppport)
Signed-off-by: Thorsten Knabe <linux@thorsten-knabe.de>
Cc: stable@kernel.org # >= 3.12
Signed-off-by: Richard Weinberger <richard@nod.at>