linux-kernel - Re: [PATCH 12/22] Input: iqs269a - use guard notation when acquiring mutex

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Message-ID: <9cc5b106-88dc-4539-b831-3cc6cb3ef860@gmail.com>
Date: Wed, 4 Sep 2024 15:53:40 +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 12/22] Input: iqs269a - use guard notation when acquiring
 mutex

On 04/09/2024 06:47, 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/iqs269a.c | 46 +++++++++++++-----------------------
>  1 file changed, 16 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/input/misc/iqs269a.c b/drivers/input/misc/iqs269a.c
> index 843f8a3f3410..c34d847fa4af 100644
> --- a/drivers/input/misc/iqs269a.c
> +++ b/drivers/input/misc/iqs269a.c

...

> @@ -453,9 +449,9 @@ static int iqs269_ati_base_get(struct iqs269_private *iqs269,
>  	if (ch_num >= IQS269_NUM_CH)
>  		return -EINVAL;
>  
> -	mutex_lock(&iqs269->lock);
> +	guard(mutex)(&iqs269->lock);
> +
>  	engine_b = be16_to_cpu(ch_reg[ch_num].engine_b);

maybe scoped_guard() to keep the scope of the mutex as it used to be?

> -	mutex_unlock(&iqs269->lock);
>  
>  	switch (engine_b & IQS269_CHx_ENG_B_ATI_BASE_MASK) {
>  	case IQS269_CHx_ENG_B_ATI_BASE_75:
> @@ -491,7 +487,7 @@ static int iqs269_ati_target_set(struct iqs269_private *iqs269,
>  	if (target > IQS269_CHx_ENG_B_ATI_TARGET_MAX)
>  		return -EINVAL;
>  
> -	mutex_lock(&iqs269->lock);
> +	guard(mutex)(&iqs269->lock);
>  
>  	engine_b = be16_to_cpu(ch_reg[ch_num].engine_b);
>  
> @@ -501,8 +497,6 @@ static int iqs269_ati_target_set(struct iqs269_private *iqs269,
>  	ch_reg[ch_num].engine_b = cpu_to_be16(engine_b);
>  	iqs269->ati_current = false;
>  
> -	mutex_unlock(&iqs269->lock);
> -
>  	return 0;
>  }
>  
> @@ -515,10 +509,9 @@ static int iqs269_ati_target_get(struct iqs269_private *iqs269,
>  	if (ch_num >= IQS269_NUM_CH)
>  		return -EINVAL;
>  
> -	mutex_lock(&iqs269->lock);
> -	engine_b = be16_to_cpu(ch_reg[ch_num].engine_b);
> -	mutex_unlock(&iqs269->lock);
> +	guard(mutex)(&iqs269->lock);

same here?

>  
> +	engine_b = be16_to_cpu(ch_reg[ch_num].engine_b);
>  	*target = (engine_b & IQS269_CHx_ENG_B_ATI_TARGET_MASK) * 32;
>  
>  	return 0;

Best regards,
Javier Carrasco