Commit-ID: 79269ee3fa1da52f392f8a4ebf3082152c1c8c58
Gitweb: http://git.kernel.org/tip/79269ee3fa1da52f392f8a4ebf3082152c1c8c58
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Wed, 19 Apr 2017 14:30:37 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Thu, 8 Jun 2017 08:25:28 -0700
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 <paulmck@xxxxxxxxxxxxxxxxxx>
---
Documentation/core-api/atomic_ops.rst | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/Documentation/core-api/atomic_ops.rst b/Documentation/core-api/atomic_ops.rst
index 55e43f1..fce9291 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;
--
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