[PATCH] rtmutex-clean-up-and-remove-some-extra-spinlocks-more

[Oleg Nesterov]

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@xxxxxxxxxx>

--- 2.6.18-rc3/kernel/rtmutex.c~	2006-08-13 18:49:28.000000000 +0400
+++ 2.6.18-rc3/kernel/rtmutex.c	2006-08-13 19:07:45.000000000 +0400
@@ -249,6 +249,7 @@ 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)) {
@@ -267,7 +268,6 @@ 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);
@@ -589,10 +589,10 @@ 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);
 }
 

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