From: Jörn Engel <joern@logfs.org>
Date: Thu, 12 Apr 2012 21:33:58 +0000 (-0400)
Subject: [SCSI] sg: prevent unwoken sleep
X-Git-Tag: v3.5-rc1~172^2~25
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6acddc5e911bb3a4a007448371ed7317c85669da;p=pandora-kernel.git

[SCSI] sg: prevent unwoken sleep

srp->done is protected by sfp->rq_list_lock everywhere, except for this
one case.  Result can be that the wake-up happens before the cacheline
with the changed srp->done has arrived, so the waiter can go back to
sleep and never be woken up again.

The wait_event_interruptible() means that anyone trying to debug this
unlikely race will likely notice everything working fine again, as the
next signal will unwedge things.  Evil.

Signed-off-by: Joern Engel <joern@logfs.org>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
---

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