rtmutex: No need to keep task ref for lock owner check (2ffa5a5c) · Commits · 戴 / test

There is no point to keep the task ref across the check for lock owner. Drop the ref before that, so the protection context is clear. Found while documenting the chain walk. Signed-off-by:

Thomas Gleixner <tglx@linutronix.de> Reviewed-by:

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

Lai Jiangshan <laijs@cn.fujitsu.com>

kernel/locking/rtmutex.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -463,6 +463,8 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,

		/* Release the task */
		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
		put_task_struct(task);

		if (!rt_mutex_owner(lock)) {
		/*
		* If the requeue above changed the top waiter, then we need
		@@ -472,9 +474,8 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
		if (top_waiter != rt_mutex_top_waiter(lock))
		wake_up_process(rt_mutex_top_waiter(lock)->task);
		raw_spin_unlock(&lock->wait_lock);
		goto out_put_task;
		return 0;
		}
		put_task_struct(task);

		/* Grab the next task */
		task = rt_mutex_owner(lock);

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