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    Subject[tip:timers/urgent] hrtimers: Move lock held region in hrtimer_interrupt()
    Commit-ID:  196951e91262fccda81147d2bcf7fdab08668b40
    Gitweb: http://git.kernel.org/tip/196951e91262fccda81147d2bcf7fdab08668b40
    Author: Thomas Gleixner <tglx@linutronix.de>
    AuthorDate: Tue, 10 Jul 2012 18:43:23 -0400
    Committer: Thomas Gleixner <tglx@linutronix.de>
    CommitDate: Wed, 11 Jul 2012 23:34:38 +0200

    hrtimers: Move lock held region in hrtimer_interrupt()

    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.

    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Reviewed-by: Ingo Molnar <mingo@kernel.org>
    Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Acked-by: Prarit Bhargava <prarit@redhat.com>
    Cc: stable@vger.kernel.org
    Signed-off-by: John Stultz <johnstul@us.ibm.com>
    Link: http://lkml.kernel.org/r/1341960205-56738-6-git-send-email-johnstul@us.ibm.com
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    ---
    kernel/hrtimer.c | 5 +++--
    1 files changed, 3 insertions(+), 2 deletions(-)

    diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
    index 3c24fb2..8f320af 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;

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