From ce3bf7ab22527183634a76512d9854a38615e4d5 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Tue, 13 Jul 2010 17:56:19 -0700 Subject: 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: John Stultz LKML-Reference: <1279068988-21864-3-git-send-email-johnstul@us.ibm.com> Signed-off-by: Thomas Gleixner --- include/linux/time.h | 16 ++++++++++++++++ kernel/time/timekeeping.c | 6 +++--- 2 files changed, 19 insertions(+), 3 deletions(-) diff --git a/include/linux/time.h b/include/linux/time.h index ea3559f0..9072df8 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -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 */ diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index caf8d4d..623fe3d 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -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); -- cgit v1.1