linux-kernel - Re: [PATCH] PM / Runtime: Fix the twice judgement in rpm

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <2969423.iZ1VgpHf54@vostro.rjw.lan>
Date:	Mon, 14 Jan 2013 13:32:04 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Chuansheng Liu <chuansheng.liu@...el.com>
Cc:	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] PM / Runtime: Fix the twice judgement in rpm_suspend/resume()

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@...el.com>
> ---
>  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.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/