[RFC PATCHv2 1/3] hrtimer: Add notifer for clock_was_set

[Fan Du <fan.du@windriver.com>]

When clock_was_set is called in case of system wall time change
or host resume from suspend state, use this notifier for places
where interested in this action.

Signed-off-by: Fan Du <fan.du@windriver.com>
---
 kernel/hrtimer.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 383319b..b7c62a9 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -755,6 +755,9 @@ static inline void retrigger_next_event(void *arg) { }
 
 #endif /* CONFIG_HIGH_RES_TIMERS */
 
+ATOMIC_NOTIFIER_HEAD(clock_change_notifier_list);
+EXPORT_SYMBOL(clock_change_notifier_list);
+
 /*
  * Clock realtime was set
  *
@@ -773,6 +776,7 @@ void clock_was_set(void)
 	on_each_cpu(retrigger_next_event, NULL, 1);
 #endif
 	timerfd_clock_was_set();
+	atomic_notifier_call_chain(&clock_change_notifier_list, 0, 0);
 }
 
 /*
-- 
1.7.9.5