3.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Christian Borntraeger <borntrae...@de.ibm.com>
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 <borntrae...@de.ibm.com>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Signed-off-by: Heiko Carstens <heiko.carst...@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidef...@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
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
--
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