[PATCH] atomic: cmpxchg

Introduce an atomic_cmpxchg operation.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/asm-powerpc/atomic.h b/include/asm-powerpc/atomic.h
index 9c0b372a46e1..37205faa9d7c 100644
--- a/include/asm-powerpc/atomic.h
+++ b/include/asm-powerpc/atomic.h
@@ -164,6 +164,8 @@ static __inline__ int atomic_dec_return(atomic_t *v)
         return t;
 }
 
+#define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n)))
+
 #define atomic_sub_and_test(a, v)       (atomic_sub_return((a), (v)) == 0)
 #define atomic_dec_and_test(v)          (atomic_dec_return((v)) == 0)