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Code Issues Releases Wiki Activity

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: John Stultz <john.stultz@linaro.org>
This commit is contained in:
John Stultz 2011-08-10 12:30:21 -07:00
parent 9e26476243
commit a28cde81ab
2 changed files with 47 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
include/linux/alarmtimer.h
View File

@ -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

21
kernel/time/alarmtimer.c
View File

@ -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);
}