linux-kernel - Re: [PATCH 07/22] Input: drv260x - use guard notation when acquiring mutex

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Message-ID: <a05a7dad-092d-4502-9b29-e76ff4b3470f@gmail.com>
Date: Wed, 4 Sep 2024 21:05:45 +0200
From: Javier Carrasco <javier.carrasco.cruz@...il.com>
To: Dmitry Torokhov <dmitry.torokhov@...il.com>, linux-input@...r.kernel.org
Cc: Michael Hennerich <michael.hennerich@...log.com>,
 Ville Syrjala <syrjala@....fi>,
 Support Opensource <support.opensource@...semi.com>,
 Eddie James <eajames@...ux.ibm.com>, Andrey Moiseev <o2g.org.ru@...il.com>,
 Hans de Goede <hdegoede@...hat.com>, Jeff LaBundy <jeff@...undy.com>,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH 07/22] Input: drv260x - use guard notation when acquiring
 mutex

On 04/09/2024 06:42, Dmitry Torokhov wrote:
> Using guard notation makes the code more compact and error handling
> more robust by ensuring that mutexes are released in all code paths
> when control leaves critical section.
> 
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
> ---
>  drivers/input/misc/drv260x.c | 50 +++++++++++++++++-------------------
>  1 file changed, 24 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/input/misc/drv260x.c b/drivers/input/misc/drv260x.c
> index 61b503835aa6..96cd6a078c8a 100644
> --- a/drivers/input/misc/drv260x.c
> +++ b/drivers/input/misc/drv260x.c
> @@ -537,64 +537,62 @@ static int drv260x_probe(struct i2c_client *client)
>  static int drv260x_suspend(struct device *dev)
>  {
>  	struct drv260x_data *haptics = dev_get_drvdata(dev);
> -	int ret = 0;
> +	int error;
>  
> -	mutex_lock(&haptics->input_dev->mutex);
> +	guard(mutex)(&haptics->input_dev->mutex);
>  
>  	if (input_device_enabled(haptics->input_dev)) {
> -		ret = regmap_update_bits(haptics->regmap,
> -					 DRV260X_MODE,
> -					 DRV260X_STANDBY_MASK,
> -					 DRV260X_STANDBY);
> -		if (ret) {
> +		error = regmap_update_bits(haptics->regmap,
> +					   DRV260X_MODE,
> +					   DRV260X_STANDBY_MASK,
> +					   DRV260X_STANDBY);
> +		if (error) {
>  			dev_err(dev, "Failed to set standby mode\n");
> -			goto out;
> +			return error;
>  		}
>  
>  		gpiod_set_value(haptics->enable_gpio, 0);
>  
> -		ret = regulator_disable(haptics->regulator);
> -		if (ret) {
> +		error = regulator_disable(haptics->regulator);
> +		if (error) {
>  			dev_err(dev, "Failed to disable regulator\n");
>  			regmap_update_bits(haptics->regmap,
>  					   DRV260X_MODE,
>  					   DRV260X_STANDBY_MASK, 0);
> +			return error;
>  		}
>  	}
> -out:
> -	mutex_unlock(&haptics->input_dev->mutex);
> -	return ret;
> +
> +	return 0;
>  }
>  
>  static int drv260x_resume(struct device *dev)
>  {
>  	struct drv260x_data *haptics = dev_get_drvdata(dev);
> -	int ret = 0;
> +	int error;
>  
> -	mutex_lock(&haptics->input_dev->mutex);
> +	guard(mutex)(&haptics->input_dev->mutex);
>  
>  	if (input_device_enabled(haptics->input_dev)) {
> -		ret = regulator_enable(haptics->regulator);
> -		if (ret) {
> +		error = regulator_enable(haptics->regulator);
> +		if (error) {
>  			dev_err(dev, "Failed to enable regulator\n");
> -			goto out;
> +			return error;
>  		}
>  
> -		ret = regmap_update_bits(haptics->regmap,
> -					 DRV260X_MODE,
> -					 DRV260X_STANDBY_MASK, 0);
> -		if (ret) {
> +		error = regmap_update_bits(haptics->regmap,
> +					   DRV260X_MODE,
> +					   DRV260X_STANDBY_MASK, 0);
> +		if (error) {
>  			dev_err(dev, "Failed to unset standby mode\n");
>  			regulator_disable(haptics->regulator);
> -			goto out;
> +			return error;
>  		}
>  
>  		gpiod_set_value(haptics->enable_gpio, 1);
>  	}
>  
> -out:
> -	mutex_unlock(&haptics->input_dev->mutex);
> -	return ret;
> +	return 0;
>  }
>  
>  static DEFINE_SIMPLE_DEV_PM_OPS(drv260x_pm_ops, drv260x_suspend, drv260x_resume);

Reviewed-by: Javier Carrasco <javier.carrasco.cruz@...il.com>