[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <1495749601-21574-19-git-send-email-paulmck@linux.vnet.ibm.com>
Date: Thu, 25 May 2017 14:58:52 -0700
From: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To: linux-kernel@...r.kernel.org
Cc: mingo@...nel.org, jiangshanlai@...il.com, dipankar@...ibm.com,
akpm@...ux-foundation.org, mathieu.desnoyers@...icios.com,
josh@...htriplett.org, tglx@...utronix.de, peterz@...radead.org,
rostedt@...dmis.org, dhowells@...hat.com, edumazet@...gle.com,
fweisbec@...il.com, oleg@...hat.com, bobby.prani@...il.com,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 19/88] 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@...ux.vnet.ibm.com>
---
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 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;
--
2.5.2
Powered by blists - more mailing lists