timekeeping: Avoid adjust kernel time once hwclock kept in UTC time

If the Hardware Clock kept in local time,kernel will adjust the time
to be UTC time.But if Hardware Clock kept in UTC time,system will make
a dummy settimeofday call first (sys_tz.tz_minuteswest = 0) to make sure
the time is not shifted,so at this point I think maybe it is not necessary
to set the kernel time once the sys_tz.tz_minuteswest is zero.

Signed-off-by: Dong Zhu <bluezhudong@gmail.com>
[jstultz: Updated to merge with conflicting changes ]
Signed-off-by: John Stultz <john.stultz@linaro.org>

diff --git a/kernel/time.c b/kernel/time.c
index f8342a41efa60de3badbcbd2f48fa1950d0d7f99..effac571589f6a75661529234815a2c7f167670c 100644 (file)
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -138,13 +138,14 @@ int persistent_clock_is_local;
  */
 static inline void warp_clock(void)
 {
-       struct timespec adjust;
+       if (sys_tz.tz_minuteswest != 0) {
+               struct timespec adjust;
 
-       adjust = current_kernel_time();
-       if (sys_tz.tz_minuteswest != 0)
                persistent_clock_is_local = 1;
-       adjust.tv_sec += sys_tz.tz_minuteswest * 60;
-       do_settimeofday(&adjust);
+               adjust = current_kernel_time();
+               adjust.tv_sec += sys_tz.tz_minuteswest * 60;
+               do_settimeofday(&adjust);
+       }
 }
 
 /*