clockevents: Provide explicit broadcast oneshot control functions

clockevents_notify() is a leftover from the early design of the
clockevents facility. It's really not a notification mechanism,
it's a multiplex call. We are way better off to have explicit
calls instead of this monstrosity.

Split out the broadcast oneshot control into a separate function
and provide inline helpers. Switch clockevents_notify() over.
This will go away once all callers are converted.

This also gets rid of the nested locking of clockevents_lock and
broadcast_lock. The broadcast oneshot control functions do not
require clockevents_lock. Only the managing functions
(setup/shutdown/suspend/resume of the broadcast device require
clockevents_lock.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Tony Lindgren <tony@atomide.com>
Link: http://lkml.kernel.org/r/13000649.8qZuEDV0OA@vostro.rjw.lan
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 19 insertions, 0 deletions

diff --git a/include/linux/tick.h b/include/linux/tick.h
index 4bb236357b03..6119321fc3be 100644
--- a/include/linux/tick.h
+++ b/include/linux/tick.h
@@ -48,12 +48,23 @@ enum tick_broadcast_mode {
 	TICK_BROADCAST_FORCE,
 };
 
+enum tick_broadcast_state {
+	TICK_BROADCAST_EXIT,
+	TICK_BROADCAST_ENTER,
+};
+
 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 extern void tick_broadcast_control(enum tick_broadcast_mode mode);
 #else
 static inline void tick_broadcast_control(enum tick_broadcast_mode mode) { }
 #endif /* BROADCAST */
 
+#if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
+extern int tick_broadcast_oneshot_control(enum tick_broadcast_state state);
+#else
+static inline int tick_broadcast_oneshot_control(enum tick_broadcast_state state) { return 0; }
+#endif
+
 static inline void tick_broadcast_enable(void)
 {
 	tick_broadcast_control(TICK_BROADCAST_ON);
@@ -66,6 +77,14 @@ static inline void tick_broadcast_force(void)
 {
 	tick_broadcast_control(TICK_BROADCAST_FORCE);
 }
+static inline int tick_broadcast_enter(void)
+{
+	return tick_broadcast_oneshot_control(TICK_BROADCAST_ENTER);
+}
+static inline void tick_broadcast_exit(void)
+{
+	tick_broadcast_oneshot_control(TICK_BROADCAST_EXIT);
+}
 
 #ifdef CONFIG_NO_HZ_COMMON
 extern int tick_nohz_tick_stopped(void);