Commit-ID: 1ca7b86062ec8473d03c5cdfd336abc8b1c8098c
Gitweb: http://git.kernel.org/tip/1ca7b86062ec8473d03c5cdfd336abc8b1c8098c
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Sat, 7 Jun 2014 09:36:13 +0200
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Sat, 21 Jun 2014 22:05:30 +0200
rtmutex: Simplify remove_waiter()
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@xxxxxxxxxxxxx>
Reviewed-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Reviewed-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
---
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 ed88021..1e8fdab 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -917,9 +917,9 @@ 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;
+ struct rt_mutex *next_lock;
unsigned long flags;
raw_spin_lock_irqsave(¤t->pi_lock, flags);
@@ -927,29 +927,31 @@ 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)) {
- struct rt_mutex_waiter *next;
+ if (rt_mutex_has_waiters(lock))
+ rt_mutex_enqueue_pi(owner, rt_mutex_top_waiter(lock));
- next = rt_mutex_top_waiter(lock);
- rt_mutex_enqueue_pi(owner, next);
- }
- __rt_mutex_adjust_prio(owner);
+ __rt_mutex_adjust_prio(owner);
- /* Store the lock on which owner is blocked or NULL */
- next_lock = task_blocked_on_lock(owner);
+ /* Store the lock on which owner is blocked or NULL */
+ 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;
--
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