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Subject[PATCH 4/6] hrtimer: Move lock held region in hrtimer_interrupt()
Date
From: Thomas Gleixner <tglx@linutronix.de>

We need to update the base offsets from this code and we need to do
that under base->lock. Move the lock held region around the
ktime_get() calls. The ktime_get() calls are going to be replaced with
a function which gets the time and the offsets atomically.

CC: Ingo Molnar <mingo@kernel.org>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Prarit Bhargava <prarit@redhat.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
---
kernel/hrtimer.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 7c20cb8..14a260a 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1263,11 +1263,10 @@ void hrtimer_interrupt(struct clock_event_device *dev)
cpu_base->nr_events++;
dev->next_event.tv64 = KTIME_MAX;

+ raw_spin_lock(&cpu_base->lock);
entry_time = now = ktime_get();
retry:
expires_next.tv64 = KTIME_MAX;
-
- raw_spin_lock(&cpu_base->lock);
/*
* We set expires_next to KTIME_MAX here with cpu_base->lock
* held to prevent that a timer is enqueued in our queue via
@@ -1344,6 +1343,7 @@ retry:
* interrupt routine. We give it 3 attempts to avoid
* overreacting on some spurious event.
*/
+ raw_spin_lock(&cpu_base->lock);
now = ktime_get();
cpu_base->nr_retries++;
if (++retries < 3)
@@ -1356,6 +1356,7 @@ retry:
*/
cpu_base->nr_hangs++;
cpu_base->hang_detected = 1;
+ raw_spin_unlock(&cpu_base->lock);
delta = ktime_sub(now, entry_time);
if (delta.tv64 > cpu_base->max_hang_time.tv64)
cpu_base->max_hang_time = delta;
--
1.7.9.5


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