From: Paul E. McKenney Date: Wed, 12 Feb 2014 21:02:22 +0000 (-0800) Subject: notifier: Substitute rcu_access_pointer() for rcu_dereference_raw() X-Git-Tag: next-20140306~34^2~19^2^2~1^2~2 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=8857563b819b;p=karo-tx-linux.git 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 Cc: Andrew Morton Cc: Linus Torvalds Reviewed-by: Josh Triplett --- 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);