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arch,xtensa: Convert smp_mb__*()

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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@infradead.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-e9rqjxr1m1ejsob9p433kmji@git.kernel.org
Cc: Chris Zankel <chris@zankel.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-xtensa@linux-xtensa.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2014-03-13 19:00:35 +01:00 committed by Ingo Molnar
parent d00a569284
commit 09a01c0ccb
3 changed files with 5 additions and 9 deletions
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7
arch/xtensa/include/asm/atomic.h
View File

@ -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 */

3
arch/xtensa/include/asm/barrier.h
View File

@ -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 */

4
arch/xtensa/include/asm/bitops.h
View File

@ -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>