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Commit 180bf812 authored by John Stultz's avatar John Stultz
Browse files

timers: Improve alarmtimer comments and minor fixes 



This patch addresses a number of minor comment improvements and
other minor issues from Thomas' review of the alarmtimers code.

CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
parent 9a7adcf5

include/linux/alarmtimer.h

+11 −1
Original line number Diff line number Diff line
@@ -13,12 +13,22 @@ enum alarmtimer_type { 
	ALARM_NUMTYPE,

};



/**

 * struct alarm - Alarm timer structure

 * @node:	timerqueue node for adding to the event list this value

 *		also includes the expiration time.

 * @period:	Period for recuring alarms

 * @function:	Function pointer to be executed when the timer fires.

 * @type:	Alarm type (BOOTTIME/REALTIME)

 * @enabled:	Flag that represents if the alarm is set to fire or not

 * @data:	Internal data value.

 */

struct alarm {

	struct timerqueue_node	node;

	ktime_t			period;

	void			(*function)(struct alarm *);

	enum alarmtimer_type	type;

	char			enabled;

	bool			enabled;

	void			*data;

};

kernel/time/alarmtimer.c

+27 −40
Original line number Diff line number Diff line
@@ -26,7 +26,15 @@ 
#include <linux/workqueue.h>

#include <linux/freezer.h>





/**

 * struct alarm_base - Alarm timer bases

 * @lock:		Lock for syncrhonized access to the base

 * @timerqueue:		Timerqueue head managing the list of events

 * @timer: 		hrtimer used to schedule events while running

 * @gettime:		Function to read the time correlating to the base

 * @base_clockid:	clockid for the base

 * @irqwork		Delayed work structure for expiring timers

 */

static struct alarm_base {

	spinlock_t		lock;

	struct timerqueue_head	timerqueue;
@@ -36,18 +44,16 @@ static struct alarm_base { 
	struct work_struct	irqwork;

} alarm_bases[ALARM_NUMTYPE];



/* rtc timer and device for setting alarm wakeups at suspend */

static struct rtc_timer		rtctimer;

static struct rtc_device	*rtcdev;



/* freezer delta & lock used to handle clock_nanosleep triggered wakeups */

static ktime_t freezer_delta;

static DEFINE_SPINLOCK(freezer_delta_lock);





/**************************************************************************

 * alarmtimer management code

 */



/*

/**

 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue

 * @base: pointer to the base where the timer is being run

 * @alarm: pointer to alarm being enqueued.
@@ -67,7 +73,7 @@ static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm) 
	}

}



/*

/**

 * alarmtimer_remove - Removes an alarm timer from an alarm_base timerqueue

 * @base: pointer to the base where the timer is running

 * @alarm: pointer to alarm being removed
@@ -91,16 +97,16 @@ static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm) 
	}

}



/*

/**

 * alarmtimer_do_work - Handles alarm being fired.

 * @work: pointer to workqueue being run

 *

 * When a timer fires, this runs through the timerqueue to see

 * which alarm timers, and run those that expired. If there are

 * more alarm timers queued, we set the hrtimer to fire in the

 * future.

 * When a alarm timer fires, this runs through the timerqueue to

 * see which alarms expired, and runs those. If there are more alarm

 * timers queued for the future, we set the hrtimer to fire when

 * when the next future alarm timer expires.

 */

void alarmtimer_do_work(struct work_struct *work)

static void alarmtimer_do_work(struct work_struct *work)

{

	struct alarm_base *base = container_of(work, struct alarm_base,

						irqwork);
@@ -141,7 +147,7 @@ void alarmtimer_do_work(struct work_struct *work) 
}





/*

/**

 * alarmtimer_fired - Handles alarm hrtimer being fired.

 * @timer: pointer to hrtimer being run

 *
@@ -156,7 +162,7 @@ static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer) 
}





/*

/**

 * alarmtimer_suspend - Suspend time callback

 * @dev: unused

 * @state: unused
@@ -230,17 +236,11 @@ static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type) 
}





/**************************************************************************

 * alarm kernel interface code

 */



/*

/**

 * alarm_init - Initialize an alarm structure

 * @alarm: ptr to alarm to be initialized

 * @type: the type of the alarm

 * @function: callback that is run when the alarm fires

 *

 * In-kernel interface to initializes the alarm structure.

 */

void alarm_init(struct alarm *alarm, enum alarmtimer_type type,

		void (*function)(struct alarm *))
@@ -252,13 +252,11 @@ void alarm_init(struct alarm *alarm, enum alarmtimer_type type, 
	alarm->enabled = 0;

}



/*

/**

 * alarm_start - Sets an alarm to fire

 * @alarm: ptr to alarm to set

 * @start: time to run the alarm

 * @period: period at which the alarm will recur

 *

 * In-kernel interface set an alarm timer.

 */

void alarm_start(struct alarm *alarm, ktime_t start, ktime_t period)

{
@@ -275,11 +273,9 @@ void alarm_start(struct alarm *alarm, ktime_t start, ktime_t period) 
	spin_unlock_irqrestore(&base->lock, flags);

}



/*

/**

 * alarm_cancel - Tries to cancel an alarm timer

 * @alarm: ptr to alarm to be canceled

 *

 * In-kernel interface to cancel an alarm timer.

 */

void alarm_cancel(struct alarm *alarm)

{
@@ -294,15 +290,9 @@ void alarm_cancel(struct alarm *alarm) 
}





/**************************************************************************

 * alarm posix interface code

 */



/*

/**

 * clock2alarm - helper that converts from clockid to alarmtypes

 * @clockid: clockid.

 *

 * Helper function that converts from clockids to alarmtypes

 */

static enum alarmtimer_type clock2alarm(clockid_t clockid)

{
@@ -313,7 +303,7 @@ static enum alarmtimer_type clock2alarm(clockid_t clockid) 
	return -1;

}



/*

/**

 * alarm_handle_timer - Callback for posix timers

 * @alarm: alarm that fired

 *
@@ -327,7 +317,7 @@ static void alarm_handle_timer(struct alarm *alarm) 
		ptr->it_overrun++;

}



/*

/**

 * alarm_clock_getres - posix getres interface

 * @which_clock: clockid

 * @tp: timespec to fill
@@ -598,9 +588,6 @@ out: 
	return ret;

}



/**************************************************************************

 * alarmtimer initialization code

 */



/* Suspend hook structures */

static const struct dev_pm_ops alarmtimer_pm_ops = {