sched/deadline, locking/rtmutex: Fix open coded check in rt_mutex_waiter_less()

rt_mutex_waiter_less() check of task deadlines is open coded. Since this
is subject to wraparound bugs, make it use the correct helper.

Reported-by: Luca Abeni <luca.abeni@unitn.it>
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1441188096-23021-4-git-send-email-juri.lelli@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 7781d801212fa32082593cf6bbb5dd44077cb78e..35e9bfcc6ad940d90e9790544106b87912a05195 100644 (file)
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -158,7 +158,8 @@ rt_mutex_waiter_less(struct rt_mutex_waiter *left,
         * then right waiter has a dl_prio() too.
         */
        if (dl_prio(left->prio))
-               return (left->task->dl.deadline < right->task->dl.deadline);
+               return dl_time_before(left->task->dl.deadline,
+                                     right->task->dl.deadline);
 
        return 0;
 }