time: Move clock_was_set_seq update before updating shadow-timekeeper

It was reported that 868a3e915f7f5eba (hrtimer: Make offset
update smarter) was causing timer problems after suspend/resume.

The problem with that change is the modification to
clock_was_set_seq in timekeeping_update is done prior to
mirroring the time state to the shadow-timekeeper. Thus the
next time we do update_wall_time() the updated sequence is
overwritten by whats in the shadow copy.

This patch moves the shadow-timekeeper mirroring to the end
of the function, after all updates have been made, so all data
is kept in sync.

(This patch also affects the update_fast_timekeeper calls which
were also problematically done prior to the mirroring).

Reported-and-tested-by: Jeremiah Mahler <jmmahler@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/1434063297-28657-2-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 90ed5db..849b932 100644 (file)
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -585,15 +585,19 @@ static void timekeeping_update(struct timekeeper *tk, unsigned int action)
        update_vsyscall(tk);
        update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
 
-       if (action & TK_MIRROR)
-               memcpy(&shadow_timekeeper, &tk_core.timekeeper,
-                      sizeof(tk_core.timekeeper));
-
        update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
        update_fast_timekeeper(&tk->tkr_raw,  &tk_fast_raw);
 
        if (action & TK_CLOCK_WAS_SET)
                tk->clock_was_set_seq++;
+       /*
+        * The mirroring of the data to the shadow-timekeeper needs
+        * to happen last here to ensure we don't over-write the
+        * timekeeper structure on the next update with stale data
+        */
+       if (action & TK_MIRROR)
+               memcpy(&shadow_timekeeper, &tk_core.timekeeper,
+                      sizeof(tk_core.timekeeper));
 }
 
 /**