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Commit ce3bf7ab authored by John Stultz's avatar John Stultz Committed by Thomas Gleixner
Browse files

time: Implement timespec_add 



After accidentally misusing timespec_add_safe, I wanted to make sure
we don't accidently trip over that issue again, so I created a simple
timespec_add() function which we can use to replace the instances
of timespec_add_safe() that don't want the overflow detection.

Signed-off-by: default avatarJohn Stultz <johnstul@us.ibm.com>
LKML-Reference: <1279068988-21864-3-git-send-email-johnstul@us.ibm.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 8c73626a

include/linux/time.h

+16 −0
Original line number Diff line number Diff line
@@ -76,9 +76,25 @@ extern unsigned long mktime(const unsigned int year, const unsigned int mon, 
			    const unsigned int min, const unsigned int sec);



extern void set_normalized_timespec(struct timespec *ts, time_t sec, s64 nsec);



/*

 * timespec_add_safe assumes both values are positive and checks

 * for overflow. It will return TIME_T_MAX if the reutrn would be

 * smaller then either of the arguments.

 */

extern struct timespec timespec_add_safe(const struct timespec lhs,

					 const struct timespec rhs);





static inline struct timespec timespec_add(struct timespec lhs,

						struct timespec rhs)

{

	struct timespec ts_delta;

	set_normalized_timespec(&ts_delta, lhs.tv_sec + rhs.tv_sec,

				lhs.tv_nsec + rhs.tv_nsec);

	return ts_delta;

}



/*

 * sub = lhs - rhs, in normalized form

 */

kernel/time/timekeeping.c

+3 −3
Original line number Diff line number Diff line
@@ -579,9 +579,9 @@ static int timekeeping_resume(struct sys_device *dev) 


	if (timespec_compare(&ts, &timekeeping_suspend_time) > 0) {

		ts = timespec_sub(ts, timekeeping_suspend_time);

		xtime = timespec_add_safe(xtime, ts);

		xtime = timespec_add(xtime, ts);

		wall_to_monotonic = timespec_sub(wall_to_monotonic, ts);

		total_sleep_time = timespec_add_safe(total_sleep_time, ts);

		total_sleep_time = timespec_add(total_sleep_time, ts);

	}

	/* re-base the last cycle value */

	timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock);
@@ -887,7 +887,7 @@ EXPORT_SYMBOL_GPL(getboottime); 
 */

void monotonic_to_bootbased(struct timespec *ts)

{

	*ts = timespec_add_safe(*ts, total_sleep_time);

	*ts = timespec_add(*ts, total_sleep_time);

}

EXPORT_SYMBOL_GPL(monotonic_to_bootbased);