From: Wengang Wang <wen.gang.wang@oracle.com>
Date: Thu, 3 Apr 2014 21:46:46 +0000 (-0700)
Subject: ocfs2: change ip_unaligned_aio to of type mutex from atomit_t
X-Git-Tag: v3.15-rc1~106^2~212
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c18ceab01240fd4c354b78d877571b729908e4a3;p=pandora-kernel.git

ocfs2: change ip_unaligned_aio to of type mutex from atomit_t

There is a problem that waitqueue_active() may check stale data thus miss
a wakeup of threads waiting on ip_unaligned_aio.

The valid value of ip_unaligned_aio is only 0 and 1 so we can change it to
be of type mutex thus the above prolem is avoid.  Another benifit is that
mutex which works as FIFO is fairer than wake_up_all().

Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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