From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/asm-s390/atomic.h |    2 ++
 1 file changed, 2 insertions(+)

diff -puN include/asm-s390/atomic.h~atomich-add-atomic64_xchg-to-s390 include/asm-s390/atomic.h
--- a/include/asm-s390/atomic.h~atomich-add-atomic64_xchg-to-s390
+++ a/include/asm-s390/atomic.h
@@ -215,6 +215,8 @@ static __inline__ void atomic64_set_mask
 	       __CSG_LOOP(v, mask, "ogr");
 }
 
+#define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
+
 static __inline__ long long atomic64_cmpxchg(atomic64_t *v,
 					     long long old, long long new)
 {
_