From: Paul E. McKenney Date: Wed, 19 Apr 2017 21:30:37 +0000 (-0700) Subject: doc/atomic_ops: Clarify smp_mb__{before,after}_atomic() X-Git-Tag: v4.13-rc1~209^2^2~67 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=79269ee3fa1da52f392f8a4ebf3082152c1c8c58;p=karo-tx-linux.git doc/atomic_ops: Clarify smp_mb__{before,after}_atomic() This commit explicitly states that surrounding a non-value-returning atomic read-modify atomic operations provides full ordering, just as is provided by value-returning atomic read-modify-write operations. Signed-off-by: Paul E. McKenney --- diff --git a/Documentation/core-api/atomic_ops.rst b/Documentation/core-api/atomic_ops.rst index 55e43f1c80de..fce929144ccd 100644 --- a/Documentation/core-api/atomic_ops.rst +++ b/Documentation/core-api/atomic_ops.rst @@ -303,6 +303,11 @@ defined which accomplish this:: void smp_mb__before_atomic(void); void smp_mb__after_atomic(void); +Preceding a non-value-returning read-modify-write atomic operation with +smp_mb__before_atomic() and following it with smp_mb__after_atomic() +provides the same full ordering that is provided by value-returning +read-modify-write atomic operations. + For example, smp_mb__before_atomic() can be used like so:: obj->dead = 1;