/**
* hrtimer_start - (re)start an relative timer on the current CPU
* @timer: the timer to be added
* @tim: expiry time
* @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
*
* Returns:
* 0 on success
* 1 when the timer was active
*/
int
hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
{
struct hrtimer_clock_base *base, *new_base;
unsigned long flags;
int ret, raise;
base = lock_hrtimer_base(timer, &flags);
/* Remove an active timer from the queue: */
ret = remove_hrtimer(timer, base);
/* Switch the timer base, if necessary: */
new_base = switch_hrtimer_base(timer, base);
if (mode == HRTIMER_MODE_REL) {
tim = ktime_add_safe(tim, new_base->get_time());
/*
* CONFIG_TIME_LOW_RES is a temporary way for architectures
* to signal that they simply return xtime in
* do_gettimeoffset(). In this case we want to round up by
* resolution when starting a relative timer, to avoid short
* timeouts. This will go away with the GTOD framework.
*/
#ifdef CONFIG_TIME_LOW_RES
tim = ktime_add_safe(tim, base->resolution);
#endif
}
timer->expires = tim;
timer_stats_hrtimer_set_start_info(timer);
/*
* Only allow reprogramming if the new base is on this CPU.
* (it might still be on another CPU if the timer was pending)
*/
enqueue_hrtimer(timer, new_base,
new_base->cpu_base == &__get_cpu_var(hrtimer_bases));
/*
* The timer may be expired and moved to the cb_pending
* list. We can not raise the softirq with base lock held due
* to a possible deadlock with runqueue lock.
*/
raise = timer->state == HRTIMER_STATE_PENDING;
/*
* We use preempt_disable to prevent this task from migrating after
* setting up the softirq and raising it. Otherwise, if me migrate
* we will raise the softirq on the wrong CPU.
*/
preempt_disable();
unlock_hrtimer_base(timer, &flags);
if (raise)
hrtimer_raise_softirq();
preempt_enable();
return ret;
}
int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
unsigned long delta_ns, const enum hrtimer_mode mode,
int wakeup)
{
struct hrtimer_clock_base *base, *new_base;
unsigned long flags;
int ret, leftmost;
base = lock_hrtimer_base(timer, &flags);
/* Remove an active timer from the queue: */
ret = remove_hrtimer(timer, base);
/* Switch the timer base, if necessary: */
new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
if (mode & HRTIMER_MODE_REL) {
tim = ktime_add_safe(tim, new_base->get_time());
/*
* CONFIG_TIME_LOW_RES is a temporary way for architectures
* to signal that they simply return xtime in
* do_gettimeoffset(). In this case we want to round up by
* resolution when starting a relative timer, to avoid short
* timeouts. This will go away with the GTOD framework.
*/
#ifdef CONFIG_TIME_LOW_RES
tim = ktime_add_safe(tim, base->resolution);
#endif
}
hrtimer_set_expires_range_ns(timer, tim, delta_ns);
timer_stats_hrtimer_set_start_info(timer);
leftmost = enqueue_hrtimer(timer, new_base);
/*
* Only allow reprogramming if the new base is on this CPU.
* (it might still be on another CPU if the timer was pending)
*
* XXX send_remote_softirq() ?
*/
if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases)
&& hrtimer_enqueue_reprogram(timer, new_base)) {
if (wakeup) {
/*
* We need to drop cpu_base->lock to avoid a
* lock ordering issue vs. rq->lock.
*/
raw_spin_unlock(&new_base->cpu_base->lock);
raise_softirq_irqoff(HRTIMER_SOFTIRQ);
local_irq_restore(flags);
return ret;
} else {
__raise_softirq_irqoff(HRTIMER_SOFTIRQ);
}
}
unlock_hrtimer_base(timer, &flags);
return ret;
}
