rtmutex: Avoid deadlock in rt_mutex_start_proxy_lock()

In the event of a lock steal or owner died,
rt_mutex_start_proxy_lock() will give the rt_mutex to the
waiting task, but it fails to release the wait_lock. This leads
to subsequent deadlocks when other tasks try to acquire the
rt_mutex.

I also removed a few extra blank lines that really spaced this
routine out. I must have been high on the \n when I wrote this
originally...

Signed-off-by: Darren Hart <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Steven Rostedt <[e-mail]>
Cc: Dinakar Guniguntala <[e-mail]>
Cc: John Stultz <[e-mail]>
LKML-Reference: <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>

kernel/rtmutex.c

···
 	if (!rt_mutex_owner(lock) || try_to_steal_lock(lock, task)) {
 		/* We got the lock for task. */
 		debug_rt_mutex_lock(lock);
-
 		rt_mutex_set_owner(lock, task, 0);
-
+		spin_unlock(&lock->wait_lock);
 		rt_mutex_deadlock_account_lock(lock, task);
 		return 1;
 	}
 
 	ret = task_blocks_on_rt_mutex(lock, waiter, task, detect_deadlock);
-
 
 	if (ret && !waiter->task) {
 		/*