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authorJohn Stultz <john.stultz@linaro.org>2011-08-10 12:30:21 -0700
committerJohn Stultz <john.stultz@linaro.org>2011-08-10 14:55:27 -0700
commita28cde81ab13cc251748a4c4ef06883dd09a10ea (patch)
treeb38ce180912957731cfe736d1d3f978342d099e1
parent9e26476243e438f4534a562660c1296a15a9e202 (diff)
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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>
-rw-r--r--include/linux/alarmtimer.h34
-rw-r--r--kernel/time/alarmtimer.c21
2 files changed, 47 insertions, 8 deletions
diff --git a/include/linux/alarmtimer.h b/include/linux/alarmtimer.h
index c854a8efa863..304124a6c982 100644
--- a/include/linux/alarmtimer.h
+++ b/include/linux/alarmtimer.h
@@ -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
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 90935591dd44..5b14cc29b6a6 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -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);
}