Documentation: Memory barrier semantics of atomic_xchg()
Add atomic_xchg() to documentation for atomic operations and
memory barriers.
Signed-off-by: Richard Braun <rbraun@sceen.net>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
diff --git a/Documentation/atomic_ops.txt b/Documentation/atomic_ops.txt
index 27f2b21..d9ca5be 100644
--- a/Documentation/atomic_ops.txt
+++ b/Documentation/atomic_ops.txt
@@ -253,6 +253,8 @@
the given new value. It returns the old value that the atomic variable v had
just before the operation.
+atomic_xchg requires explicit memory barriers around the operation.
+
int atomic_cmpxchg(atomic_t *v, int old, int new);
This performs an atomic compare exchange operation on the atomic value v,