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| author | DengChao <chao.deng@linaro.org> | 2015-12-13 05:26:42 +0100 |
|---|---|---|
| committer | John Stultz <john.stultz@linaro.org> | 2015-12-17 01:50:56 +0100 |
| commit | c796348774f15c6e682834ed288bcae0f2c95707 (patch) | |
| tree | 693a7d9879af61c226bd2b51d6e8bbe7920388e4 /kernel/time/ntp.c | |
| parent | ntp: Change time_reftime to time64_t and utilize 64bit __ktime_get_real_seconds (diff) | |
| download | linux-c796348774f15c6e682834ed288bcae0f2c95707.tar.xz linux-c796348774f15c6e682834ed288bcae0f2c95707.zip | |
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>
Diffstat (limited to 'kernel/time/ntp.c')
| -rw-r--r-- | kernel/time/ntp.c | 16 |
1 files changed, 9 insertions, 7 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; |