linux-kernel - Re: [PATCH 12/21] cpuidle: call cpuidle_get_driver() from after taking cpuidle_driver

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Date:	Thu, 26 Sep 2013 00:04:39 +0200
From:	Daniel Lezcano <daniel.lezcano@...aro.org>
To:	Viresh Kumar <viresh.kumar@...aro.org>, rjw@...k.pl
CC:	linaro-kernel@...ts.linaro.org, patches@...aro.org,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 12/21] cpuidle: call cpuidle_get_driver() from after taking
 cpuidle_driver_lock

On 09/22/2013 03:21 AM, Viresh Kumar wrote:
> cpuidle_driver_lock is taken correctly at most of the places but at few places
> calls to cpuidle_get_driver() are done from outside of this lock.
> 
> Fix them by calling cpuidle_get_driver() after taking cpuidle_driver_lock.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>

Acked-by: Daniel Lezcano <daniel.lezcano@...aro.org>

> ---
>  drivers/cpuidle/driver.c | 3 ++-
>  drivers/cpuidle/sysfs.c  | 3 ++-
>  2 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
> index 6279e1c..7b2510a 100644
> --- a/drivers/cpuidle/driver.c
> +++ b/drivers/cpuidle/driver.c
> @@ -340,10 +340,11 @@ struct cpuidle_driver *cpuidle_driver_ref(void)
>   */
>  void cpuidle_driver_unref(void)
>  {
> -	struct cpuidle_driver *drv = cpuidle_get_driver();
> +	struct cpuidle_driver *drv;
>  
>  	spin_lock(&cpuidle_driver_lock);
>  
> +	drv = cpuidle_get_driver();
>  	if (drv && !WARN_ON(drv->refcnt <= 0))
>  		drv->refcnt--;
>  
> diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c
> index 8739cc0..a022393 100644
> --- a/drivers/cpuidle/sysfs.c
> +++ b/drivers/cpuidle/sysfs.c
> @@ -52,9 +52,10 @@ static ssize_t show_current_driver(struct device *dev,
>  				   char *buf)
>  {
>  	ssize_t ret;
> -	struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
> +	struct cpuidle_driver *cpuidle_driver;
>  
>  	spin_lock(&cpuidle_driver_lock);
> +	cpuidle_driver = cpuidle_get_driver();
>  	if (cpuidle_driver)
>  		ret = sprintf(buf, "%s\n", cpuidle_driver->name);
>  	else
> 


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