Exemple #1
0
/**
 * rt_mutex_finish_proxy_lock() - Complete lock acquisition
 * @lock:		the rt_mutex we were woken on
 * @to:			the timeout, null if none. hrtimer should already have
 * 			been started.
 * @waiter:		the pre-initialized rt_mutex_waiter
 * @detect_deadlock:	perform deadlock detection (1) or not (0)
 *
 * Complete the lock acquisition started our behalf by another thread.
 *
 * Returns:
 *  0 - success
 * <0 - error, one of -EINTR, -ETIMEDOUT, or -EDEADLK
 *
 * Special API call for PI-futex requeue support
 */
int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
			       struct hrtimer_sleeper *to,
			       struct rt_mutex_waiter *waiter,
			       int detect_deadlock)
{
	int ret;

	raw_spin_lock(&lock->wait_lock);

	set_current_state(TASK_INTERRUPTIBLE);

	ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter);

	set_current_state(TASK_RUNNING);

	if (unlikely(ret))
		remove_waiter(lock, waiter);

	/*
	 * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might
	 * have to fix that up.
	 */
	fixup_rt_mutex_waiters(lock);

	raw_spin_unlock(&lock->wait_lock);

	return ret;
}
Exemple #2
0
/*
 * Slow path lock function:
 */
static int __sched
rt_mutex_slowlock(struct rt_mutex *lock, int state,
		  struct hrtimer_sleeper *timeout,
		  int detect_deadlock)
{
	struct rt_mutex_waiter waiter;
	int ret = 0;

	debug_rt_mutex_init_waiter(&waiter);
	waiter.task = NULL;

	raw_spin_lock(&lock->wait_lock);

	/* Try to acquire the lock again: */
	if (try_to_take_rt_mutex(lock)) {
		raw_spin_unlock(&lock->wait_lock);
		return 0;
	}

	set_current_state(state);

	/* Setup the timer, when timeout != NULL */
	if (unlikely(timeout)) {
		hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS);
		if (!hrtimer_active(&timeout->timer))
			timeout->task = NULL;
	}

	ret = __rt_mutex_slowlock(lock, state, timeout, &waiter,
				  detect_deadlock);

	set_current_state(TASK_RUNNING);

	if (unlikely(waiter.task))
		remove_waiter(lock, &waiter);

	/*
	 * try_to_take_rt_mutex() sets the waiter bit
	 * unconditionally. We might have to fix that up.
	 */
	fixup_rt_mutex_waiters(lock);

	raw_spin_unlock(&lock->wait_lock);

	/* Remove pending timer: */
	if (unlikely(timeout))
		hrtimer_cancel(&timeout->timer);

	/*
	 * Readjust priority, when we did not get the lock. We might
	 * have been the pending owner and boosted. Since we did not
	 * take the lock, the PI boost has to go.
	 */
	if (unlikely(ret))
		rt_mutex_adjust_prio(current);

	debug_rt_mutex_free_waiter(&waiter);

	return ret;
}
Exemple #3
0
/*
 * Slow path lock function:
 */
static int __sched
rt_mutex_slowlock(struct rt_mutex *lock, int state,
		  struct hrtimer_sleeper *timeout,
		  int detect_deadlock)
{
	struct rt_mutex_waiter waiter;
	int ret = 0;

	debug_rt_mutex_init_waiter(&waiter);
	RB_CLEAR_NODE(&waiter.pi_tree_entry);
	RB_CLEAR_NODE(&waiter.tree_entry);

	raw_spin_lock(&lock->wait_lock);

	/* Try to acquire the lock again: */
	if (try_to_take_rt_mutex(lock, current, NULL)) {
		raw_spin_unlock(&lock->wait_lock);
		return 0;
	}

	set_current_state(state);

	/* Setup the timer, when timeout != NULL */
	if (unlikely(timeout)) {
		hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS);
		if (!hrtimer_active(&timeout->timer))
			timeout->task = NULL;
	}

	ret = task_blocks_on_rt_mutex(lock, &waiter, current, detect_deadlock);

	if (likely(!ret))
		ret = __rt_mutex_slowlock(lock, state, timeout, &waiter);

	set_current_state(TASK_RUNNING);

	if (unlikely(ret))
		remove_waiter(lock, &waiter);

	/*
	 * try_to_take_rt_mutex() sets the waiter bit
	 * unconditionally. We might have to fix that up.
	 */
	fixup_rt_mutex_waiters(lock);

	raw_spin_unlock(&lock->wait_lock);

	/* Remove pending timer: */
	if (unlikely(timeout))
		hrtimer_cancel(&timeout->timer);

	debug_rt_mutex_free_waiter(&waiter);

	return ret;
}
Exemple #4
0
/**
 * rt_mutex_finish_proxy_lock() - Complete lock acquisition
 * @lock:		the rt_mutex we were woken on
 * @to:			the timeout, null if none. hrtimer should already have
 * 			been started.
 * @waiter:		the pre-initialized rt_mutex_waiter
 * @detect_deadlock:	perform deadlock detection (1) or not (0)
 *
 * Complete the lock acquisition started our behalf by another thread.
 *
 * Returns:
 *  0 - success
 * <0 - error, one of -EINTR, -ETIMEDOUT, or -EDEADLK
 *
 * Special API call for PI-futex requeue support
 */
int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
			       struct hrtimer_sleeper *to,
			       struct rt_mutex_waiter *waiter,
			       int detect_deadlock)
{
	int ret;

	raw_spin_lock(&lock->wait_lock);

	set_current_state(TASK_INTERRUPTIBLE);

	ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter,
				  detect_deadlock);

	set_current_state(TASK_RUNNING);

	if (unlikely(waiter->task))
		remove_waiter(lock, waiter);

	/*
	 * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might
	 * have to fix that up.
	 */
	fixup_rt_mutex_waiters(lock);

	raw_spin_unlock(&lock->wait_lock);

	/*
	 * Readjust priority, when we did not get the lock. We might have been
	 * the pending owner and boosted. Since we did not take the lock, the
	 * PI boost has to go.
	 */
	if (unlikely(ret))
		rt_mutex_adjust_prio(current);

	return ret;
}
Exemple #5
0
/*
 * Slow path lock function:
 */
static int __sched
rt_mutex_slowlock(struct rt_mutex *lock, int state,
		  struct hrtimer_sleeper *timeout,
		  int detect_deadlock)
{
	int ret = 0, saved_lock_depth = -1;
	struct rt_mutex_waiter waiter;
	unsigned long flags;

	debug_rt_mutex_init_waiter(&waiter);

	raw_spin_lock_irqsave(&lock->wait_lock, flags);
	init_lists(lock);

	/* Try to acquire the lock again: */
	if (try_to_take_rt_mutex(lock, current, NULL)) {
		raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
		return 0;
	}

	set_current_state(state);

	/* Setup the timer, when timeout != NULL */
	if (unlikely(timeout)) {
		hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS);
		if (!hrtimer_active(&timeout->timer))
			timeout->task = NULL;
	}

	ret = task_blocks_on_rt_mutex(lock, &waiter, current, detect_deadlock, flags, 0);

	/*
	 * We drop the BKL here before we go into the wait loop to avoid a
	 * possible deadlock in the scheduler.
	 *
	 * Note: This must be done after we call task_blocks_on_rt_mutex
	 *  because rt_release_bkl() releases the wait_lock and will
	 *  cause a race between setting the mark waiters flag in
	 *  the owner field and adding this task to the wait list. Those
	 *  two must be done within the protection of the wait_lock.
	 */
	if (unlikely(current->lock_depth >= 0))
		saved_lock_depth = rt_release_bkl(lock, flags);

	if (likely(!ret))
		ret = __rt_mutex_slowlock(lock, state, timeout, &waiter, flags);

	set_current_state(TASK_RUNNING);

	if (unlikely(ret))
		remove_waiter(lock, &waiter, flags);
	BUG_ON(!plist_node_empty(&waiter.list_entry));

	/*
	 * try_to_take_rt_mutex() sets the waiter bit
	 * unconditionally. We might have to fix that up.
	 */
	fixup_rt_mutex_waiters(lock);

	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);

	/* Remove pending timer: */
	if (unlikely(timeout))
		hrtimer_cancel(&timeout->timer);

	/* Must we reaquire the BKL? */
	if (unlikely(saved_lock_depth >= 0))
		rt_reacquire_bkl(saved_lock_depth);

	debug_rt_mutex_free_waiter(&waiter);

	return ret;
}