From 69f0d429c413fe96db2c187475cebcc6e3a8c7f5 Mon Sep 17 00:00:00 2001

From: Alex Shi <alex.shi@linaro.org>

Date: Thu, 13 Jul 2017 14:18:24 +0800

Subject: [PATCH] locking/rtmutex: Remove unnecessary priority adjustment

Git-commit: 69f0d429c413fe96db2c187475cebcc6e3a8c7f5

Patch-mainline: v4.13-rc1

References: bsc#1050549

We don't need to adjust priority before adding a new pi_waiter, the

priority only needs to be updated after pi_waiter change or task

priority change.

Steven Rostedt pointed out:

  "Interesting, I did some git mining and this was added with the original

   entry of the rtmutex.c (23f78d4a03c5). Looking at even that version, I

   don't see the purpose of adjusting the task prio here. It is done

   before anything changes in the task."

Signed-off-by: Alex Shi <alex.shi@linaro.org>

Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

Cc: Juri Lelli <juri.lelli@arm.com>

Cc: Linus Torvalds <torvalds@linux-foundation.org>

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>

Cc: Sebastian Siewior <bigeasy@linutronix.de>

Cc: Steven Rostedt <rostedt@goodmis.org>

Cc: Thomas Gleixner <tglx@linutronix.de>

Link: http://lkml.kernel.org/r/1499926704-28841-1-git-send-email-alex.shi@linaro.org

[ Enhance the changelog. ]

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>

---

 kernel/locking/rtmutex.c | 1 -

 1 file changed, 1 deletion(-)

diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c

index 78069895032a..649dc9d3951a 100644

--- a/kernel/locking/rtmutex.c

+++ b/kernel/locking/rtmutex.c

@@ -963,7 +963,6 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,

 		return -EDEADLK;

 	raw_spin_lock(&task->pi_lock);

-	rt_mutex_adjust_prio(task);

 	waiter->task = task;

 	waiter->lock = lock;

 	waiter->prio = task->prio;

-- 

2.12.0