linux-kernel - Re: [PATCH 16/22] Input: max8997_haptic - use guard notation when acquiring mutex

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Message-ID: <c0040ed2-2877-4acd-9cf7-101d40cda642@gmail.com>
Date: Wed, 4 Sep 2024 21:12:49 +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 16/22] Input: max8997_haptic - use guard notation when
 acquiring mutex

On 04/09/2024 06:48, 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/max8997_haptic.c | 15 +++++----------
>  1 file changed, 5 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/input/misc/max8997_haptic.c b/drivers/input/misc/max8997_haptic.c
> index 11cac4b7dddc..2853455daef2 100644
> --- a/drivers/input/misc/max8997_haptic.c
> +++ b/drivers/input/misc/max8997_haptic.c
> @@ -153,19 +153,19 @@ static void max8997_haptic_enable(struct max8997_haptic *chip)
>  {
>  	int error;
>  
> -	mutex_lock(&chip->mutex);
> +	guard(mutex)(&chip->mutex);
>  
>  	error = max8997_haptic_set_duty_cycle(chip);
>  	if (error) {
>  		dev_err(chip->dev, "set_pwm_cycle failed, error: %d\n", error);
> -		goto out;
> +		return;
>  	}
>  
>  	if (!chip->enabled) {
>  		error = regulator_enable(chip->regulator);
>  		if (error) {
>  			dev_err(chip->dev, "Failed to enable regulator\n");
> -			goto out;
> +			return;
>  		}
>  		max8997_haptic_configure(chip);
>  		if (chip->mode == MAX8997_EXTERNAL_MODE) {
> @@ -173,19 +173,16 @@ static void max8997_haptic_enable(struct max8997_haptic *chip)
>  			if (error) {
>  				dev_err(chip->dev, "Failed to enable PWM\n");
>  				regulator_disable(chip->regulator);
> -				goto out;
> +				return;
>  			}
>  		}
>  		chip->enabled = true;
>  	}
> -
> -out:
> -	mutex_unlock(&chip->mutex);
>  }
>  
>  static void max8997_haptic_disable(struct max8997_haptic *chip)
>  {
> -	mutex_lock(&chip->mutex);
> +	guard(mutex)(&chip->mutex);
>  
>  	if (chip->enabled) {
>  		chip->enabled = false;
> @@ -194,8 +191,6 @@ static void max8997_haptic_disable(struct max8997_haptic *chip)
>  			pwm_disable(chip->pwm);
>  		regulator_disable(chip->regulator);
>  	}
> -
> -	mutex_unlock(&chip->mutex);
>  }
>  
>  static void max8997_haptic_play_effect_work(struct work_struct *work)

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