linux-kernel - Re: [PATCH 05/22] Input: da7280 - use guard notation when acquiring mutex and spinlock

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Message-ID: <df3cc6e6-f6c2-4025-850a-3bf8449bd95d@gmail.com>
Date: Wed, 4 Sep 2024 21:02:19 +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 05/22] Input: da7280 - use guard notation when acquiring
 mutex and spinlock

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 locks are released in all code paths
> when control leaves critical section.
> 
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
> ---
>  drivers/input/misc/da7280.c | 26 ++++++++++++--------------
>  1 file changed, 12 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/input/misc/da7280.c b/drivers/input/misc/da7280.c
> index 1629b7ea4cbd..e4a605c6af15 100644
> --- a/drivers/input/misc/da7280.c
> +++ b/drivers/input/misc/da7280.c
> @@ -1263,39 +1263,37 @@ static int da7280_suspend(struct device *dev)
>  {
>  	struct da7280_haptic *haptics = dev_get_drvdata(dev);
>  
> -	mutex_lock(&haptics->input_dev->mutex);
> +	guard(mutex)(&haptics->input_dev->mutex);
>  
>  	/*
>  	 * Make sure no new requests will be submitted while device is
>  	 * suspended.
>  	 */
> -	spin_lock_irq(&haptics->input_dev->event_lock);
> -	haptics->suspended = true;
> -	spin_unlock_irq(&haptics->input_dev->event_lock);
> +	scoped_guard(spinlock_irq, &haptics->input_dev->event_lock) {
> +		haptics->suspended = true;
> +	}
>  
>  	da7280_haptic_stop(haptics);
>  
> -	mutex_unlock(&haptics->input_dev->mutex);
> -
>  	return 0;
>  }
>  
>  static int da7280_resume(struct device *dev)
>  {
>  	struct da7280_haptic *haptics = dev_get_drvdata(dev);
> -	int retval;
> +	int error;
>  
> -	mutex_lock(&haptics->input_dev->mutex);
> +	guard(mutex)(&haptics->input_dev->mutex);
>  
> -	retval = da7280_haptic_start(haptics);
> -	if (!retval) {
> -		spin_lock_irq(&haptics->input_dev->event_lock);
> +	error = da7280_haptic_start(haptics);
> +	if (error)
> +		return error;
> +
> +	scoped_guard(spinlock_irq, &haptics->input_dev->event_lock) {
>  		haptics->suspended = false;
> -		spin_unlock_irq(&haptics->input_dev->event_lock);
>  	}
>  
> -	mutex_unlock(&haptics->input_dev->mutex);
> -	return retval;
> +	return 0;
>  }
>  
>  #ifdef CONFIG_OF

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