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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-02-12 13:02:22 -0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-02-26 06:35:13 -0800
commit8857563b819b140aa8c9be920cfe44d5d3f808b7 (patch)
tree1fd7568acae29cd051e41f665c83a50c1bcdb10e
parentadd1f0995454374d90c9d6b2c420d2fba3d0a4e3 (diff)
downloadlinux-8857563b819b140aa8c9be920cfe44d5d3f808b7.tar.bz2
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@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
-rw-r--r--kernel/notifier.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/notifier.c b/kernel/notifier.c
index 2d5cc4ccff7f..db4c8b08a50c 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);