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authorDengChao <chao.deng@linaro.org>2015-12-13 12:26:42 +0800
committerJohn Stultz <john.stultz@linaro.org>2015-12-16 16:50:56 -0800
commitc796348774f15c6e682834ed288bcae0f2c95707 (patch)
tree693a7d9879af61c226bd2b51d6e8bbe7920388e4
parent0af864651b459afb0435ee8786a19cbe5a044cdb (diff)
ntp: Fix second_overflow's input parameter type to be 64bits
The function "second_overflow" uses "unsign long" as its input parameter type which will overflow after year 2106 on 32bit systems. Thus this patch replaces it with time64_t type. While the 64-bit division is expensive, "next_ntp_leap_sec" has been calculated already, so we can just re-use it in the TIME_INS/DEL cases, allowing one expensive division per leapsecond instead of re-doing the divsion once a second after the leap flag has been set. Signed-off-by: DengChao <chao.deng@linaro.org> [jstultz: Tweaked commit message] Signed-off-by: John Stultz <john.stultz@linaro.org>
-rw-r--r--kernel/time/ntp.c16
-rw-r--r--kernel/time/ntp_internal.h2
2 files changed, 10 insertions, 8 deletions
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index e947bfddd2c2..36f2ca09aa5e 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -16,6 +16,7 @@
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/rtc.h>
+#include <linux/math64.h>
#include "ntp_internal.h"
#include "timekeeping_internal.h"
@@ -394,10 +395,11 @@ ktime_t ntp_get_next_leap(void)
*
* Also handles leap second processing, and returns leap offset
*/
-int second_overflow(unsigned long secs)
+int second_overflow(time64_t secs)
{
s64 delta;
int leap = 0;
+ s32 rem;
/*
* Leap second processing. If in leap-insert state at the end of the
@@ -408,19 +410,19 @@ int second_overflow(unsigned long secs)
case TIME_OK:
if (time_status & STA_INS) {
time_state = TIME_INS;
- ntp_next_leap_sec = secs + SECS_PER_DAY -
- (secs % SECS_PER_DAY);
+ div_s64_rem(secs, SECS_PER_DAY, &rem);
+ ntp_next_leap_sec = secs + SECS_PER_DAY - rem;
} else if (time_status & STA_DEL) {
time_state = TIME_DEL;
- ntp_next_leap_sec = secs + SECS_PER_DAY -
- ((secs+1) % SECS_PER_DAY);
+ div_s64_rem(secs + 1, SECS_PER_DAY, &rem);
+ ntp_next_leap_sec = secs + SECS_PER_DAY - rem;
}
break;
case TIME_INS:
if (!(time_status & STA_INS)) {
ntp_next_leap_sec = TIME64_MAX;
time_state = TIME_OK;
- } else if (secs % SECS_PER_DAY == 0) {
+ } else if (secs == ntp_next_leap_sec) {
leap = -1;
time_state = TIME_OOP;
printk(KERN_NOTICE
@@ -431,7 +433,7 @@ int second_overflow(unsigned long secs)
if (!(time_status & STA_DEL)) {
ntp_next_leap_sec = TIME64_MAX;
time_state = TIME_OK;
- } else if ((secs + 1) % SECS_PER_DAY == 0) {
+ } else if (secs == ntp_next_leap_sec) {
leap = 1;
ntp_next_leap_sec = TIME64_MAX;
time_state = TIME_WAIT;
diff --git a/kernel/time/ntp_internal.h b/kernel/time/ntp_internal.h
index af924470eac0..d8a7c11fa71a 100644
--- a/kernel/time/ntp_internal.h
+++ b/kernel/time/ntp_internal.h
@@ -6,7 +6,7 @@ extern void ntp_clear(void);
/* Returns how long ticks are at present, in ns / 2^NTP_SCALE_SHIFT. */
extern u64 ntp_tick_length(void);
extern ktime_t ntp_get_next_leap(void);
-extern int second_overflow(unsigned long secs);
+extern int second_overflow(time64_t secs);
extern int ntp_validate_timex(struct timex *);
extern int __do_adjtimex(struct timex *, struct timespec64 *, s32 *);
extern void __hardpps(const struct timespec64 *, const struct timespec64 *);