From: Thomas Gleixner Date: Sat, 7 Jun 2014 10:10:36 +0000 (+0200) Subject: rtmutex: No need to keep task ref for lock owner check X-Git-Tag: firefly_0821_release~176^2~3504^2~19 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=2ffa5a5cd2fe792b6399c903d5172adf088d8ff7;p=firefly-linux-kernel-4.4.55.git rtmutex: No need to keep task ref for lock owner check 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 Reviewed-by: Steven Rostedt Reviewed-by: Lai Jiangshan --- diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 39c9f8075e14..cd517091fb21 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -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);