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 <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Linus Torvalds <[email protected]> Reviewed-by: Josh Triplett <[email protected]>
torvalds · Feb 26, 2014 · 8857563 · 8857563
1 parent add1f09
commit 8857563
Showing 1 changed file with 1 addition and 1 deletion.
diff --git 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);