arch,arm64: Convert smp_mb__*()

AARGH64 uses ll/sc primitives that do not imply any barriers for the
normal atomics, therefore smp_mb__{before,after} should be a full
barrier.

Since AARGH64 doesn't use asm-generic/barrier.h, add the required
definitions to its asm/barrier.h.

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-8p5iclqgy78al33kck3ht7nr@git.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Gang <gang.chen@asianux.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/arm64/include/asm/atomic.h

@@ -152,11 +152,6 @@ static inline int __atomic_add_unless(atomic_t *v, int a, int u)
 
 #define atomic_add_negative(i,v) (atomic_add_return(i, v) < 0)
 
-#define smp_mb__before_atomic_dec()	smp_mb()
-#define smp_mb__after_atomic_dec()	smp_mb()
-#define smp_mb__before_atomic_inc()	smp_mb()
-#define smp_mb__after_atomic_inc()	smp_mb()
-
 /*
  * 64-bit atomic operations.
  */

arch/arm64/include/asm/barrier.h

@@ -98,6 +98,9 @@ do {									\
 #define set_mb(var, value)	do { var = value; smp_mb(); } while (0)
 #define nop()		asm volatile("nop");
 
+#define smp_mb__before_atomic()	smp_mb()
+#define smp_mb__after_atomic()	smp_mb()
+
 #endif	/* __ASSEMBLY__ */
 
 #endif	/* __ASM_BARRIER_H */

arch/arm64/include/asm/bitops.h

@@ -17,17 +17,8 @@
 #define __ASM_BITOPS_H
 
 #include <linux/compiler.h>
-
 #include <asm/barrier.h>
 
-/*
- * clear_bit may not imply a memory barrier
- */
-#ifndef smp_mb__before_clear_bit
-#define smp_mb__before_clear_bit()	smp_mb()
-#define smp_mb__after_clear_bit()	smp_mb()
-#endif
-
 #ifndef _LINUX_BITOPS_H
 #error only <linux/bitops.h> can be included directly
 #endif