From: Tejun Heo <tj@kernel.org>
Date: Tue, 14 Aug 2012 00:08:19 +0000 (-0700)
Subject: workqueue: add missing wmb() in clear_work_data()
X-Git-Tag: omap-for-v3.7-rc1/fixes-cpufreq-signed~52^2~32
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=23657bb192f14b789e4c478def8f11ecc95b4f6c;p=pandora-kernel.git

workqueue: add missing wmb() in clear_work_data()

Any operation which clears PENDING should be preceded by a wmb to
guarantee that the next PENDING owner sees all the changes made before
PENDING release.

There are only two places where PENDING is cleared -
set_work_cpu_and_clear_pending() and clear_work_data().  The caller of
the former already does smp_wmb() but the latter doesn't have any.

Move the wmb above set_work_cpu_and_clear_pending() into it and add
one to clear_work_data().

There hasn't been any report related to this issue, and, given how
clear_work_data() is used, it is extremely unlikely to have caused any
actual problems on any architecture.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
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