From: Juri Lelli <juri.lelli@arm.com>
Date: Wed, 2 Sep 2015 10:01:35 +0000 (+0100)
Subject: sched/deadline, locking/rtmutex: Fix open coded check in rt_mutex_waiter_less()
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=f52405757e4e9bddd868d6b8ca501d58f292969f;p=deliverable%2Flinux.git

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 7781d801212f..35e9bfcc6ad9 100644
--- 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;
 }