linux-kernel - Re: [PATCH 09/22] Input: drv2667 - use guard notation when acquiring mutex

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Message-ID: <8b860de1-9387-4865-8ea0-58eefae81fc1@gmail.com>
Date: Wed, 4 Sep 2024 21:08:32 +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,
 Javier Carrasco Cruz <javier.carrasco.cruz@...il.com>
Subject: Re: [PATCH 09/22] Input: drv2667 - 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/drv2667.c | 44 +++++++++++++++++-------------------
>  1 file changed, 21 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/input/misc/drv2667.c b/drivers/input/misc/drv2667.c
> index ad49845374b9..906292625f84 100644
> --- a/drivers/input/misc/drv2667.c
> +++ b/drivers/input/misc/drv2667.c
> @@ -402,59 +402,57 @@ static int drv2667_probe(struct i2c_client *client)
>  static int drv2667_suspend(struct device *dev)
>  {
>  	struct drv2667_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, DRV2667_CTRL_2,
> -					 DRV2667_STANDBY, DRV2667_STANDBY);
> -		if (ret) {
> +		error = regmap_update_bits(haptics->regmap, DRV2667_CTRL_2,
> +					   DRV2667_STANDBY, DRV2667_STANDBY);
> +		if (error) {
>  			dev_err(dev, "Failed to set standby mode\n");
>  			regulator_disable(haptics->regulator);
> -			goto out;
> +			return error;
>  		}
>  
> -		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,
>  					   DRV2667_CTRL_2,
>  					   DRV2667_STANDBY, 0);
> +			return error;
>  		}
>  	}
> -out:
> -	mutex_unlock(&haptics->input_dev->mutex);
> -	return ret;
> +
> +	return 0;
>  }
>  
>  static int drv2667_resume(struct device *dev)
>  {
>  	struct drv2667_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, DRV2667_CTRL_2,
> -					 DRV2667_STANDBY, 0);
> -		if (ret) {
> +		error = regmap_update_bits(haptics->regmap, DRV2667_CTRL_2,
> +					   DRV2667_STANDBY, 0);
> +		if (error) {
>  			dev_err(dev, "Failed to unset standby mode\n");
>  			regulator_disable(haptics->regulator);
> -			goto out;
> +			return error;
>  		}
>  
>  	}
>  
> -out:
> -	mutex_unlock(&haptics->input_dev->mutex);
> -	return ret;
> +	return 0;
>  }
>  
>  static DEFINE_SIMPLE_DEV_PM_OPS(drv2667_pm_ops, drv2667_suspend, drv2667_resume);


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