sched/preempt: Fix preempt notifiers documentation about hlist_del() within unsafe iteration

preempt_notifier_unregister() documents:

  "This is safe to call from within a preemption notifier."

However, both fire_sched_in_preempt_notifiers() and
fire_sched_out_preempt_notifiers() are using hlist_for_each_entry(),
which is not safe against entry removal during iteration.

Inspection of the KVM code does not reveal any use of
preempt_notifier_unregister() within the preempt notifiers.

Therefore, fix the comment.

Signed-off-by: Mathieu Desnoyers <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
This commit is contained in:
Mathieu Desnoyers 2015-05-17 12:53:10 -04:00 • committed by Ingo Molnar
commit d84525a845

View file

@ -2165,7 +2165,7 @@ EXPORT_SYMBOL_GPL(preempt_notifier_register);
* preempt_notifier_unregister - no longer interested in preemption notifications
* @notifier: notifier struct to unregister
*
* This is safe to call from within a preemption notifier.
* This is *not* safe to call from within a preemption notifier.
*/
void preempt_notifier_unregister(struct preempt_notifier *notifier)
{