sh: Fix up smp_mb__xxx() memory barriers for SH-4A SMP.
In the past these were simply wrapping to barrier() which was sufficient
on SH SMP platforms predating SH-4A. Unfortunately due to ll/sc semantics
an explicit synco is needed in these cases, which is sorted for us by
just switching these over to smp_mb(). smp_mb() also has the benefit of
being wrapped to barrier() in the UP and non-SH4A cases, so old behaviour
is maintained for those parts.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/include/asm/atomic.h b/arch/sh/include/asm/atomic.h
index e8e7813..b16388d 100644
--- a/arch/sh/include/asm/atomic.h
+++ b/arch/sh/include/asm/atomic.h
@@ -78,11 +78,10 @@
#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
-/* Atomic operations are already serializing on SH */
-#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()
+#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()
#include <asm-generic/atomic-long.h>
#include <asm-generic/atomic64.h>