From: Christian Borntraeger <borntraeger@de.ibm.com>
Date: Tue, 5 Aug 2014 07:57:51 +0000 (+0200)
Subject: s390/locking: Reenable optimistic spinning
X-Git-Tag: omap-for-v3.17/fixes-against-rc2~136^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=36e7fdaa1a04fcf65b864232e1af56a51c7814d6;p=pandora-kernel.git

s390/locking: Reenable optimistic spinning

commit 4badad352a6bb202ec68afa7a574c0bb961e5ebc (locking/mutex: Disable
optimistic spinning on some architectures) fenced spinning for
architectures without proper cmpxchg.
There is no need to disable mutex spinning on s390, though:
The instructions CS,CSG and friends provide the proper guarantees.
(We dont implement cmpxchg with locks).

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---

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