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Commit a28cde81 authored by John Stultz's avatar John Stultz
Browse files

alarmtimers: Add more refined alarm state tracking 



In order to allow for functionality like try_to_cancel, add
more refined  state tracking (similar to hrtimers).

CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
parent 9e264762

include/linux/alarmtimer.h

+33 −1
Original line number Diff line number Diff line
@@ -18,6 +18,11 @@ enum alarmtimer_restart { 
	ALARMTIMER_RESTART,

};





#define ALARMTIMER_STATE_INACTIVE	0x00

#define ALARMTIMER_STATE_ENQUEUED	0x01

#define ALARMTIMER_STATE_CALLBACK	0x02



/**

 * struct alarm - Alarm timer structure

 * @node:	timerqueue node for adding to the event list this value
@@ -32,7 +37,7 @@ struct alarm { 
	struct timerqueue_node	node;

	enum alarmtimer_restart	(*function)(struct alarm *, ktime_t now);

	enum alarmtimer_type	type;

	bool			enabled;

	int			state;

	void			*data;

};
@@ -43,4 +48,31 @@ void alarm_cancel(struct alarm *alarm); 


u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval);



/*

 * A alarmtimer is active, when it is enqueued into timerqueue or the

 * callback function is running.

 */

static inline int alarmtimer_active(const struct alarm *timer)

{

	return timer->state != ALARMTIMER_STATE_INACTIVE;

}



/*

 * Helper function to check, whether the timer is on one of the queues

 */

static inline int alarmtimer_is_queued(struct alarm *timer)

{

	return timer->state & ALARMTIMER_STATE_ENQUEUED;

}



/*

 * Helper function to check, whether the timer is running the callback

 * function

 */

static inline int alarmtimer_callback_running(struct alarm *timer)

{

	return timer->state & ALARMTIMER_STATE_CALLBACK;

}





#endif

kernel/time/alarmtimer.c

+14 −7
Original line number Diff line number Diff line
@@ -126,6 +126,8 @@ static struct rtc_device *alarmtimer_get_rtcdev(void) 
static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)

{

	timerqueue_add(&base->timerqueue, &alarm->node);

	alarm->state |= ALARMTIMER_STATE_ENQUEUED;



	if (&alarm->node == timerqueue_getnext(&base->timerqueue)) {

		hrtimer_try_to_cancel(&base->timer);

		hrtimer_start(&base->timer, alarm->node.expires,
@@ -147,7 +149,12 @@ static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm) 
{

	struct timerqueue_node *next = timerqueue_getnext(&base->timerqueue);



	if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))

		return;



	timerqueue_del(&base->timerqueue, &alarm->node);

	alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;



	if (next == &alarm->node) {

		hrtimer_try_to_cancel(&base->timer);

		next = timerqueue_getnext(&base->timerqueue);
@@ -188,16 +195,18 @@ static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer) 
		alarm = container_of(next, struct alarm, node);



		timerqueue_del(&base->timerqueue, &alarm->node);

		alarm->enabled = 0;

		alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;



		alarm->state |= ALARMTIMER_STATE_CALLBACK;

		spin_unlock_irqrestore(&base->lock, flags);

		if (alarm->function)

			restart = alarm->function(alarm, now);

		spin_lock_irqsave(&base->lock, flags);

		alarm->state &= ~ALARMTIMER_STATE_CALLBACK;



		if (restart != ALARMTIMER_NORESTART) {

			timerqueue_add(&base->timerqueue, &alarm->node);

			alarm->enabled = 1;

			alarm->state |= ALARMTIMER_STATE_ENQUEUED;

		}

	}
@@ -305,7 +314,7 @@ void alarm_init(struct alarm *alarm, enum alarmtimer_type type, 
	timerqueue_init(&alarm->node);

	alarm->function = function;

	alarm->type = type;

	alarm->enabled = 0;

	alarm->state = ALARMTIMER_STATE_INACTIVE;

}



/**
@@ -319,11 +328,10 @@ void alarm_start(struct alarm *alarm, ktime_t start) 
	unsigned long flags;



	spin_lock_irqsave(&base->lock, flags);

	if (alarm->enabled)

	if (alarmtimer_active(alarm))

		alarmtimer_remove(base, alarm);

	alarm->node.expires = start;

	alarmtimer_enqueue(base, alarm);

	alarm->enabled = 1;

	spin_unlock_irqrestore(&base->lock, flags);

}
@@ -337,9 +345,8 @@ void alarm_cancel(struct alarm *alarm) 
	unsigned long flags;



	spin_lock_irqsave(&base->lock, flags);

	if (alarm->enabled)

	if (alarmtimer_is_queued(alarm))

		alarmtimer_remove(base, alarm);

	alarm->enabled = 0;

	spin_unlock_irqrestore(&base->lock, flags);

}