[PATCH 2/2] timer: Replace base-> 'running_timer' with 'busy'

[Viresh Kumar <viresh.kumar@linaro.org>]

We don't need to track the running timer for a cpu base anymore, but sill need
to check business of base for sanity checking during CPU hotplug.

Lets replace 'running_timer' with 'busy' for handle that efficiently.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 kernel/time/timer.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 364644811485..2db05206594b 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -77,7 +77,7 @@ struct tvec_root {
 
 struct tvec_base {
 	spinlock_t lock;
-	struct timer_list *running_timer;
+	bool busy;
 	unsigned long timer_jiffies;
 	unsigned long next_timer;
 	unsigned long active_timers;
@@ -1180,6 +1180,8 @@ static inline void __run_timers(struct tvec_base *base)
 		spin_unlock_irq(&base->lock);
 		return;
 	}
+
+	base->busy = true;
 	while (time_after_eq(jiffies, base->timer_jiffies)) {
 		struct list_head work_list;
 		struct list_head *head = &work_list;
@@ -1236,7 +1238,6 @@ static inline void __run_timers(struct tvec_base *base)
 
 			timer_stats_account_timer(timer);
 
-			base->running_timer = timer;
 			timer_set_running(timer);
 			detach_expired_timer(timer, base);
 
@@ -1270,7 +1271,7 @@ static inline void __run_timers(struct tvec_base *base)
 			}
 		}
 	}
-	base->running_timer = NULL;
+	base->busy = false;
 	spin_unlock_irq(&base->lock);
 }
 
@@ -1675,7 +1676,7 @@ static void migrate_timers(int cpu)
 	spin_lock_irq(&new_base->lock);
 	spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
 
-	BUG_ON(old_base->running_timer);
+	BUG_ON(old_base->busy);
 
 	for (i = 0; i < TVR_SIZE; i++)
 		migrate_timer_list(new_base, old_base->tv1.vec + i);
-- 
2.3.0.rc0.44.ga94655d