/*
* 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);
waiter.task = NULL;
spin_lock_irqsave(&lock->wait_lock, flags);
init_lists(lock);
/* Try to acquire the lock again: */
if (try_to_take_rt_mutex(lock)) {
spin_unlock_irqrestore(&lock->wait_lock, flags);
return 0;
}
/*
* We drop the BKL here before we go into the wait loop to avoid a
* possible deadlock in the scheduler.
*/
if (unlikely(current->lock_depth >= 0))
saved_lock_depth = rt_release_bkl(lock, flags);
set_current_state(state);
/* Setup the timer, when timeout != NULL */
if (unlikely(timeout))
hrtimer_start(&timeout->timer, timeout->timer.expires,
HRTIMER_MODE_ABS);
for (;;) {
unsigned long saved_flags;
/* Try to acquire the lock: */
if (try_to_take_rt_mutex(lock))
break;
/*
* TASK_INTERRUPTIBLE checks for signals and
* timeout. Ignored otherwise.
*/
if (unlikely(state == TASK_INTERRUPTIBLE)) {
/* Signal pending? */
if (signal_pending(current))
ret = -EINTR;
if (timeout && !timeout->task)
ret = -ETIMEDOUT;
if (ret)
break;
}
/*
* waiter.task is NULL the first time we come here and
* when we have been woken up by the previous owner
* but the lock got stolen by a higher prio task.
*/
if (!waiter.task) {
ret = task_blocks_on_rt_mutex(lock, &waiter,
detect_deadlock, flags);
/*
* If we got woken up by the owner then start loop
* all over without going into schedule to try
* to get the lock now:
*/
if (unlikely(!waiter.task))
continue;
if (unlikely(ret))
break;
}
saved_flags = current->flags & PF_NOSCHED;
current->flags &= ~PF_NOSCHED;
spin_unlock_irq(&lock->wait_lock);
debug_rt_mutex_print_deadlock(&waiter);
if (waiter.task)
schedule_rt_mutex(lock);
spin_lock_irq(&lock->wait_lock);
current->flags |= saved_flags;
set_current_state(state);
}
set_current_state(TASK_RUNNING);
if (unlikely(waiter.task))
remove_waiter(lock, &waiter, flags);
/*
* try_to_take_rt_mutex() sets the waiter bit
* unconditionally. We might have to fix that up.
*/
fixup_rt_mutex_waiters(lock);
spin_unlock_irqrestore(&lock->wait_lock, flags);
/* 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);
/* 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;
}
/*
* 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;
}