clocksource: Fix bug with max_deferment margin calculation

commit b1f919664d04a8d0ba29cb76673c7ca3325a2006 upstream.

In order to leave a margin of 12.5% we should >> 3 not >> 5.

Signed-off-by: Yang Honggang (Joseph) <eagle.rtlinux@gmail.com>
[jstultz: Modified commit subject]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index e0980f0d9a0ad2d559b98c12f26317b55044cad1..8b270063b5152452d093428ee0044229a5c3e89f 100644 (file)
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -531,7 +531,7 @@ static u64 clocksource_max_deferment(struct clocksource *cs)
         * note a margin of 12.5% is used because this can be computed with
         * a shift, versus say 10% which would require division.
         */
-       return max_nsecs - (max_nsecs >> 5);
+       return max_nsecs - (max_nsecs >> 3);
 }
 
 #ifndef CONFIG_ARCH_USES_GETTIMEOFFSET
@@ -653,7 +653,7 @@ void __clocksource_updatefreq_scale(struct clocksource *cs, u32 scale, u32 freq)
         * ~ 0.06ppm granularity for NTP. We apply the same 12.5%
         * margin as we do in clocksource_max_deferment()
         */
-       sec = (cs->mask - (cs->mask >> 5));
+       sec = (cs->mask - (cs->mask >> 3));
        do_div(sec, freq);
        do_div(sec, scale);
        if (!sec)