From: Oleg Nesterov <oleg@tv-sign.ru>

On top of Steven's rtmutex-clean-up-and-remove-some-extra-spinlocks.patch

There are still 2 get_task_struct()s under ->pi_lock.  Imho, this is
confusing.  Move them outside of ->pi_lock protected section.  The task
can't go away, otherwise it was unsafe to take task->pi_lock.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Esben Nielsen <nielsen.esben@googlemail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 kernel/rtmutex.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff -puN kernel/rtmutex.c~rtmutex-clean-up-and-remove-some-extra-spinlocks-more kernel/rtmutex.c
--- a/kernel/rtmutex.c~rtmutex-clean-up-and-remove-some-extra-spinlocks-more
+++ a/kernel/rtmutex.c
@@ -251,6 +251,7 @@ static int rt_mutex_adjust_prio_chain(st
 
 	/* Grab the next task */
 	task = rt_mutex_owner(lock);
+	get_task_struct(task);
 	spin_lock_irqsave(&task->pi_lock, flags);
 
 	if (waiter == rt_mutex_top_waiter(lock)) {
@@ -269,7 +270,6 @@ static int rt_mutex_adjust_prio_chain(st
 		__rt_mutex_adjust_prio(task);
 	}
 
-	get_task_struct(task);
 	spin_unlock_irqrestore(&task->pi_lock, flags);
 
 	top_waiter = rt_mutex_top_waiter(lock);
@@ -591,10 +591,10 @@ void rt_mutex_adjust_pi(struct task_stru
 		return;
 	}
 
-	/* gets dropped in rt_mutex_adjust_prio_chain()! */
-	get_task_struct(task);
 	spin_unlock_irqrestore(&task->pi_lock, flags);
 
+	/* gets dropped in rt_mutex_adjust_prio_chain()! */
+	get_task_struct(task);
 	rt_mutex_adjust_prio_chain(task, 0, NULL, NULL, task);
 }
 
_