Messages in this thread Patch in this message | | | Date | Thu, 12 Mar 2015 15:13:14 -0400 | From | Steven Rostedt <> | Subject | [PATCH RT 07/39] rtmutex: Simplify remove_waiter() |
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3.14.34-rt32-rc1 stable review patch. If anyone has any objections, please let me know.
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From: Thomas Gleixner <tglx@linutronix.de>
upstream commit: 1ca7b86062ec8473d03c5cdfd336abc8b1c8098c
Exit right away, when the removed waiter was not the top priority waiter on the lock. Get rid of the extra indent level.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Conflicts: kernel/locking/rtmutex.c --- kernel/locking/rtmutex.c | 36 +++++++++++++++++++----------------- 1 file changed, 19 insertions(+), 17 deletions(-)
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 400026ec7f05..6c74a0525dcb 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -985,7 +985,7 @@ static void wakeup_next_waiter(struct rt_mutex *lock) static void remove_waiter(struct rt_mutex *lock, struct rt_mutex_waiter *waiter) { - int first = (waiter == rt_mutex_top_waiter(lock)); + bool is_top_waiter = (waiter == rt_mutex_top_waiter(lock)); struct task_struct *owner = rt_mutex_owner(lock); struct rt_mutex *next_lock = NULL; unsigned long flags; @@ -995,30 +995,32 @@ static void remove_waiter(struct rt_mutex *lock, current->pi_blocked_on = NULL; raw_spin_unlock_irqrestore(¤t->pi_lock, flags); - if (!owner) + /* + * Only update priority if the waiter was the highest priority + * waiter of the lock and there is an owner to update. + */ + if (!owner || !is_top_waiter) return; - if (first) { + raw_spin_lock_irqsave(&owner->pi_lock, flags); - raw_spin_lock_irqsave(&owner->pi_lock, flags); + rt_mutex_dequeue_pi(owner, waiter); - rt_mutex_dequeue_pi(owner, waiter); + if (rt_mutex_has_waiters(lock)) + rt_mutex_enqueue_pi(owner, rt_mutex_top_waiter(lock)); - if (rt_mutex_has_waiters(lock)) { - struct rt_mutex_waiter *next; + __rt_mutex_adjust_prio(owner); - next = rt_mutex_top_waiter(lock); - rt_mutex_enqueue_pi(owner, next); - } - __rt_mutex_adjust_prio(owner); - - /* Store the lock on which owner is blocked or NULL */ - if (rt_mutex_real_waiter(owner->pi_blocked_on)) - next_lock = task_blocked_on_lock(owner); + /* Store the lock on which owner is blocked or NULL */ + if (rt_mutex_real_waiter(owner->pi_blocked_on)) + next_lock = task_blocked_on_lock(owner); - raw_spin_unlock_irqrestore(&owner->pi_lock, flags); - } + raw_spin_unlock_irqrestore(&owner->pi_lock, flags); + /* + * Don't walk the chain, if the owner task is not blocked + * itself. + */ if (!next_lock) return; -- 2.1.4
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