linux-kernel - RE: [PATCH 1/2] rtc: max31335: remove unecessary locking

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Message-ID: 
 <CY4PR03MB3399960604BF0CAAA108231F9B732@CY4PR03MB3399.namprd03.prod.outlook.com>
Date: Tue, 16 Jan 2024 10:47:04 +0000
From: "Miclaus, Antoniu" <Antoniu.Miclaus@...log.com>
To: "alexandre.belloni@...tlin.com" <alexandre.belloni@...tlin.com>
CC: "linux-rtc@...r.kernel.org" <linux-rtc@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 1/2] rtc: max31335: remove unecessary locking

> From: Alexandre Belloni <alexandre.belloni@...tlin.com>
> 
> There is no race condition when accessing MAX31335_STATUS1 because it is
> always about clearing the alarm interrupt bit.
> 
> Signed-off-by: Alexandre Belloni <alexandre.belloni@...tlin.com>
Reviewed-by: Antoniu Miclaus <antoniu.miclaus@...log.com>
> ---
>  drivers/rtc/rtc-max31335.c | 14 +++-----------
>  1 file changed, 3 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/rtc/rtc-max31335.c b/drivers/rtc/rtc-max31335.c
> index 3ddfe71bbb56..2ce23f60a7f3 100644
> --- a/drivers/rtc/rtc-max31335.c
> +++ b/drivers/rtc/rtc-max31335.c
> @@ -348,27 +348,19 @@ static int max31335_alarm_irq_enable(struct device
> *dev, unsigned int enabled)
>  static irqreturn_t max31335_handle_irq(int irq, void *dev_id)
>  {
>  	struct max31335_data *max31335 = dev_id;
> -	struct mutex *lock = &max31335->rtc->ops_lock;
>  	int ret, status;
> 
> -	mutex_lock(lock);
> -
>  	ret = regmap_read(max31335->regmap, MAX31335_STATUS1,
> &status);
>  	if (ret)
> -		goto exit;
> +		return IRQ_HANDLED;
> 
>  	if (FIELD_GET(MAX31335_STATUS1_A1F, status)) {
> -		ret = regmap_update_bits(max31335->regmap,
> MAX31335_STATUS1,
> -					 MAX31335_STATUS1_A1F, 0);
> -		if (ret)
> -			goto exit;
> +		regmap_update_bits(max31335->regmap,
> MAX31335_STATUS1,
> +				   MAX31335_STATUS1_A1F, 0);
> 
>  		rtc_update_irq(max31335->rtc, 1, RTC_AF | RTC_IRQF);
>  	}
> 
> -exit:
> -	mutex_unlock(lock);
> -
>  	return IRQ_HANDLED;
>  }
> 
> --
> 2.43.0