Commit-ID: 8857563b819b140aa8c9be920cfe44d5d3f808b7
Gitweb: http://git.kernel.org/tip/8857563b819b140aa8c9be920cfe44d5d3f808b7
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Wed, 12 Feb 2014 13:02:22 -0800
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Wed, 26 Feb 2014 06:35:13 -0800
notifier: Substitute rcu_access_pointer() for rcu_dereference_raw()
(Trivial patch.)
If the code is looking at the RCU-protected pointer itself, but not
dereferencing it, the rcu_dereference() functions can be downgraded
to rcu_access_pointer(). This commit makes this downgrade in
__blocking_notifier_call_chain() which simply compares the RCU-protected
pointer against NULL with no dereferencing.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
---
kernel/notifier.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/notifier.c b/kernel/notifier.c
index 2d5cc4c..db4c8b0 100644
--- a/kernel/notifier.c
+++ b/kernel/notifier.c
@@ -309,7 +309,7 @@ int __blocking_notifier_call_chain(struct blocking_notifier_head *nh,
* racy then it does not matter what the result of the test
* is, we re-check the list after having taken the lock anyway:
*/
- if (rcu_dereference_raw(nh->head)) {
+ if (rcu_access_pointer(nh->head)) {
down_read(&nh->rwsem);
ret = notifier_call_chain(&nh->head, val, v, nr_to_call,
nr_calls);
--
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