Re: [PATCH] PM / Runtime: Fix the twice judgement in rpm_suspend/resume()

From: Rafael J. Wysocki
Date: Mon Jan 14 2013 - 07:26:00 EST


On Tuesday, January 15, 2013 01:48:18 AM Chuansheng Liu wrote:
>
> In function rpm_suspend/resume(), when going into the for(;;),
> the pre-condition judgement has been done, and the variable runtime_status
> are always protected by &power.lock, so it is not necessary to judge
> them again before unlock_irq &power.lock in for(;;).
>
> This patch clean them up.

Well, I don't really think this fixes anything. Yes, we may save one check
here and there, but the current code follows the wait_event() convention.

Thanks,
Rafael


> Signed-off-by: liu chuansheng <chuansheng.liu@xxxxxxxxx>
> ---
> drivers/base/power/runtime.c | 18 +++++++++---------
> 1 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
> index 3148b10..32d6497 100644
> --- a/drivers/base/power/runtime.c
> +++ b/drivers/base/power/runtime.c
> @@ -377,14 +377,14 @@ static int rpm_suspend(struct device *dev, int rpmflags)
> for (;;) {
> prepare_to_wait(&dev->power.wait_queue, &wait,
> TASK_UNINTERRUPTIBLE);
> - if (dev->power.runtime_status != RPM_SUSPENDING)
> - break;
>
> spin_unlock_irq(&dev->power.lock);
>
> schedule();
>
> spin_lock_irq(&dev->power.lock);
> + if (dev->power.runtime_status != RPM_SUSPENDING)
> + break;
> }
> finish_wait(&dev->power.wait_queue, &wait);
> goto repeat;
> @@ -557,15 +557,15 @@ static int rpm_resume(struct device *dev, int rpmflags)
> for (;;) {
> prepare_to_wait(&dev->power.wait_queue, &wait,
> TASK_UNINTERRUPTIBLE);
> - if (dev->power.runtime_status != RPM_RESUMING
> - && dev->power.runtime_status != RPM_SUSPENDING)
> - break;
>
> spin_unlock_irq(&dev->power.lock);
>
> schedule();
>
> spin_lock_irq(&dev->power.lock);
> + if (dev->power.runtime_status != RPM_RESUMING
> + && dev->power.runtime_status != RPM_SUSPENDING)
> + break;
> }
> finish_wait(&dev->power.wait_queue, &wait);
> goto repeat;
> @@ -989,15 +989,15 @@ static void __pm_runtime_barrier(struct device *dev)
> for (;;) {
> prepare_to_wait(&dev->power.wait_queue, &wait,
> TASK_UNINTERRUPTIBLE);
> - if (dev->power.runtime_status != RPM_SUSPENDING
> - && dev->power.runtime_status != RPM_RESUMING
> - && !dev->power.idle_notification)
> - break;
> spin_unlock_irq(&dev->power.lock);
>
> schedule();
>
> spin_lock_irq(&dev->power.lock);
> + if (dev->power.runtime_status != RPM_SUSPENDING
> + && dev->power.runtime_status != RPM_RESUMING
> + && !dev->power.idle_notification)
> + break;
> }
> finish_wait(&dev->power.wait_queue, &wait);
> }
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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