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time: Implement timespec_add

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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: John Stultz <johnstul@us.ibm.com>
LKML-Reference: <1279068988-21864-3-git-send-email-johnstul@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
John Stultz 2010-07-13 17:56:19 -07:00 committed by Thomas Gleixner
parent 8c73626ab2
commit ce3bf7ab22
2 changed files with 19 additions and 3 deletions
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16
include/linux/time.h
View file

@ -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
*/

6
kernel/time/timekeeping.c
View file

@ -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);