[tip:locking/core] arch,xtensa: Convert smp_mb__*()

From: tip-bot for Peter Zijlstra
Date: Fri Apr 18 2014 - 09:13:49 EST


Commit-ID: 09a01c0ccb1837abb28afcfdd668fa0dfabed928
Gitweb: http://git.kernel.org/tip/09a01c0ccb1837abb28afcfdd668fa0dfabed928
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Thu, 13 Mar 2014 19:00:35 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 18 Apr 2014 14:20:47 +0200

arch,xtensa: Convert smp_mb__*()

Xtensa SMP has compare-and-swap which is fully serializing, therefore
its exising smp_mb__{before,after}_clear_bit() appear unduly heavy.

Implement the new barriers as barrier().

Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Acked-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-e9rqjxr1m1ejsob9p433kmji@xxxxxxxxxxxxxx
Cc: Chris Zankel <chris@xxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>
Cc: Max Filippov <jcmvbkbc@xxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-xtensa@xxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/xtensa/include/asm/atomic.h | 7 +------
arch/xtensa/include/asm/barrier.h | 3 +++
arch/xtensa/include/asm/bitops.h | 4 +---
3 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/arch/xtensa/include/asm/atomic.h b/arch/xtensa/include/asm/atomic.h
index e7fb447..e5103b4 100644
--- a/arch/xtensa/include/asm/atomic.h
+++ b/arch/xtensa/include/asm/atomic.h
@@ -19,6 +19,7 @@
#ifdef __KERNEL__
#include <asm/processor.h>
#include <asm/cmpxchg.h>
+#include <asm/barrier.h>

#define ATOMIC_INIT(i) { (i) }

@@ -387,12 +388,6 @@ static inline void atomic_set_mask(unsigned int mask, atomic_t *v)
#endif
}

-/* Atomic operations are already serializing */
-#define smp_mb__before_atomic_dec() barrier()
-#define smp_mb__after_atomic_dec() barrier()
-#define smp_mb__before_atomic_inc() barrier()
-#define smp_mb__after_atomic_inc() barrier()
-
#endif /* __KERNEL__ */

#endif /* _XTENSA_ATOMIC_H */
diff --git a/arch/xtensa/include/asm/barrier.h b/arch/xtensa/include/asm/barrier.h
index 0a24b04..5b88774 100644
--- a/arch/xtensa/include/asm/barrier.h
+++ b/arch/xtensa/include/asm/barrier.h
@@ -13,6 +13,9 @@
#define rmb() barrier()
#define wmb() mb()

+#define smp_mb__before_atomic() barrier()
+#define smp_mb__after_atomic() barrier()
+
#include <asm-generic/barrier.h>

#endif /* _XTENSA_SYSTEM_H */
diff --git a/arch/xtensa/include/asm/bitops.h b/arch/xtensa/include/asm/bitops.h
index 7b6873a..3f44fa2 100644
--- a/arch/xtensa/include/asm/bitops.h
+++ b/arch/xtensa/include/asm/bitops.h
@@ -21,9 +21,7 @@

#include <asm/processor.h>
#include <asm/byteorder.h>
-
-#define smp_mb__before_clear_bit() smp_mb()
-#define smp_mb__after_clear_bit() smp_mb()
+#include <asm/barrier.h>

#include <asm-generic/bitops/non-atomic.h>

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