/*
* 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;
}
/*
* Slow path to release a rt-mutex:
*/
static void __sched
rt_mutex_slowunlock(struct rt_mutex *lock)
{
raw_spin_lock(&lock->wait_lock);
debug_rt_mutex_unlock(lock);
rt_mutex_deadlock_account_unlock(current);
if (!rt_mutex_has_waiters(lock)) {
lock->owner = NULL;
raw_spin_unlock(&lock->wait_lock);
return;
}
wakeup_next_waiter(lock);
raw_spin_unlock(&lock->wait_lock);
/* Undo pi boosting if necessary: */
rt_mutex_adjust_prio(current);
}
/**
* 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;
}
/*
* Slow path to release a rt_mutex spin_lock style
*/
static void fastcall noinline __sched
rt_spin_lock_slowunlock(struct rt_mutex *lock)
{
unsigned long flags;
spin_lock_irqsave(&lock->wait_lock, flags);
debug_rt_mutex_unlock(lock);
rt_mutex_deadlock_account_unlock(current);
if (!rt_mutex_has_waiters(lock)) {
lock->owner = NULL;
spin_unlock_irqrestore(&lock->wait_lock, flags);
return;
}
wakeup_next_waiter(lock, 1);
spin_unlock_irqrestore(&lock->wait_lock, flags);
/* Undo pi boosting.when necessary */
rt_mutex_adjust_prio(current);
}
/*
* 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)
{
struct rt_mutex_waiter waiter;
int ret = 0;
debug_rt_mutex_init_waiter(&waiter);
waiter.task = NULL;
spin_lock(&lock->wait_lock);
/* Try to acquire the lock again: */
if (try_to_take_rt_mutex(lock)) {
spin_unlock(&lock->wait_lock);
return 0;
}
set_current_state(state);
/* Setup the timer, when timeout != NULL */
if (unlikely(timeout))
hrtimer_start(&timeout->timer, timeout->timer.expires,
HRTIMER_MODE_ABS);
for (;;) {
/* 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);
/*
* 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)) {
/*
* Reset the return value. We might
* have returned with -EDEADLK and the
* owner released the lock while we
* were walking the pi chain.
*/
ret = 0;
continue;
}
if (unlikely(ret))
break;
}
spin_unlock(&lock->wait_lock);
debug_rt_mutex_print_deadlock(&waiter);
if (waiter.task)
schedule_rt_mutex(lock);
spin_lock(&lock->wait_lock);
set_current_state(state);
}
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);
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;
}
