alarmtimers: Change alarmtimer functions to return alarmtimer_restart values
In order to properly fix the denial of service issue with high freq
periodic alarm timers, we need to push the re-arming logic into the
alarm timer handler, much as the hrtimer code does.
This patch introduces alarmtimer_restart enum and changes the
alarmtimer handler declarations to use it as a return value. Further,
to ease following changes, it extends the alarmtimer handler functions
to also take the time at expiration. No logic is yet modified.
CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
diff --git a/include/linux/alarmtimer.h b/include/linux/alarmtimer.h
index c5d6095..0289eb2 100644
--- a/include/linux/alarmtimer.h
+++ b/include/linux/alarmtimer.h
@@ -13,6 +13,11 @@
ALARM_NUMTYPE,
};
+enum alarmtimer_restart {
+ ALARMTIMER_NORESTART,
+ ALARMTIMER_RESTART,
+};
+
/**
* struct alarm - Alarm timer structure
* @node: timerqueue node for adding to the event list this value
@@ -26,14 +31,14 @@
struct alarm {
struct timerqueue_node node;
ktime_t period;
- void (*function)(struct alarm *);
+ enum alarmtimer_restart (*function)(struct alarm *, ktime_t now);
enum alarmtimer_type type;
bool enabled;
void *data;
};
void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
- void (*function)(struct alarm *));
+ enum alarmtimer_restart (*function)(struct alarm *, ktime_t));
void alarm_start(struct alarm *alarm, ktime_t start, ktime_t period);
void alarm_cancel(struct alarm *alarm);