Patch "s390/locking: Reenable optimistic spinning" has been added to the 3.16-stable tree

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This is a note to let you know that I've just added the patch titled

    s390/locking: Reenable optimistic spinning

to the 3.16-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     s390-locking-reenable-optimistic-spinning.patch
and it can be found in the queue-3.16 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From 36e7fdaa1a04fcf65b864232e1af56a51c7814d6 Mon Sep 17 00:00:00 2001
From: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Date: Tue, 5 Aug 2014 09:57:51 +0200
Subject: s390/locking: Reenable optimistic spinning

From: Christian Borntraeger <borntraeger@xxxxxxxxxx>

commit 36e7fdaa1a04fcf65b864232e1af56a51c7814d6 upstream.

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@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/s390/Kconfig |    1 +
 1 file changed, 1 insertion(+)

--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -92,6 +92,7 @@ config S390
 	select ARCH_INLINE_WRITE_UNLOCK_IRQ
 	select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
 	select ARCH_SAVE_PAGE_KEYS if HIBERNATION
+	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_USE_CMPXCHG_LOCKREF
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select BUILDTIME_EXTABLE_SORT


Patches currently in stable-queue which might be from borntraeger@xxxxxxxxxx are

queue-3.16/s390-locking-reenable-optimistic-spinning.patch
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