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

Oleg Nesterov
2006-08-13T11:31:37Z

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>

--- 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);
}