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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-02-12 13:02:22 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-02-26 06:35:13 -0800 |
| commit | 8857563b819b140aa8c9be920cfe44d5d3f808b7 (patch) | |
| tree | 1fd7568acae29cd051e41f665c83a50c1bcdb10e /kernel/notifier.c | |
| parent | add1f0995454374d90c9d6b2c420d2fba3d0a4e3 (diff) | |
| download | lwn-8857563b819b140aa8c9be920cfe44d5d3f808b7.tar.gz lwn-8857563b819b140aa8c9be920cfe44d5d3f808b7.zip | |
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>
Diffstat (limited to 'kernel/notifier.c')
| -rw-r--r-- | kernel/notifier.c | 2 |
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); |