linux-kernel - Re: [PATCH v2 04/11] watchdog: rzg2l_wdt: Check return status of pm_runtime

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Message-ID: <ddc0b42c-bf88-4c0d-b938-8bd7ff7b329a@tuxon.dev>
Date: Wed, 31 Jan 2024 12:35:50 +0200
From: claudiu beznea <claudiu.beznea@...on.dev>
To: Biju Das <biju.das.jz@...renesas.com>,
 "wim@...ux-watchdog.org" <wim@...ux-watchdog.org>,
 "linux@...ck-us.net" <linux@...ck-us.net>,
 "robh+dt@...nel.org" <robh+dt@...nel.org>,
 "krzysztof.kozlowski+dt@...aro.org" <krzysztof.kozlowski+dt@...aro.org>,
 "conor+dt@...nel.org" <conor+dt@...nel.org>,
 "geert+renesas@...der.be" <geert+renesas@...der.be>,
 "magnus.damm@...il.com" <magnus.damm@...il.com>,
 "mturquette@...libre.com" <mturquette@...libre.com>,
 "sboyd@...nel.org" <sboyd@...nel.org>,
 "p.zabel@...gutronix.de" <p.zabel@...gutronix.de>
Cc: "linux-watchdog@...r.kernel.org" <linux-watchdog@...r.kernel.org>,
 "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
 "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
 "linux-renesas-soc@...r.kernel.org" <linux-renesas-soc@...r.kernel.org>,
 "linux-clk@...r.kernel.org" <linux-clk@...r.kernel.org>,
 Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: Re: [PATCH v2 04/11] watchdog: rzg2l_wdt: Check return status of
 pm_runtime_put()

Hi, Biju,

On 31.01.2024 12:32, Biju Das wrote:
> Hi Claudiu,
> 
> Thanks for the feedback.
> 
>> -----Original Message-----
>> From: Claudiu <claudiu.beznea@...on.dev>
>> Sent: Wednesday, January 31, 2024 10:20 AM
>> Subject: [PATCH v2 04/11] watchdog: rzg2l_wdt: Check return status of
>> pm_runtime_put()
>>
>> From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
>>
>> pm_runtime_put() may return an error code. Check its return status.
>>
>> Along with it the rzg2l_wdt_set_timeout() function was updated to
>> propagate the result of rzg2l_wdt_stop() to its caller.
>>
>> Fixes: 2cbc5cd0b55f ("watchdog: Add Watchdog Timer driver for RZ/G2L")
>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
>> ---
>>
>> Changes in v2:
>> - propagate the return code of rzg2l_wdt_stop() to it's callers
>>
>>  drivers/watchdog/rzg2l_wdt.c | 11 +++++++++--
>>  1 file changed, 9 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/watchdog/rzg2l_wdt.c b/drivers/watchdog/rzg2l_wdt.c
>> index d87d4f50180c..7bce093316c4 100644
>> --- a/drivers/watchdog/rzg2l_wdt.c
>> +++ b/drivers/watchdog/rzg2l_wdt.c
>> @@ -144,9 +144,13 @@ static int rzg2l_wdt_start(struct watchdog_device
>> *wdev)  static int rzg2l_wdt_stop(struct watchdog_device *wdev)  {
>>  	struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
>> +	int ret;
>>
>>  	rzg2l_wdt_reset(priv);
>> -	pm_runtime_put(wdev->parent);
>> +
>> +	ret = pm_runtime_put(wdev->parent);
>> +	if (ret < 0)
>> +		return ret;
> 
> Do we need to check the return code? So far we didn't hit this condition.
> If you are planning to do it, then just 
> 
> return pm_runtime_put(wdev->parent);

pm_runtime_put() may return 1 if the device is suspended (which is not
considered error) as explained here:

https://patchwork.kernel.org/project/linux-renesas-soc/patch/20240122111115.2861835-4-claudiu.beznea.uj@bp.renesas.com/

Thank you,
Claudiu Beznea

> 
> Cheers,
> Biju
> 
>>
>>  	return 0;
> 
> 
>>  }
>> @@ -163,7 +167,10 @@ static int rzg2l_wdt_set_timeout(struct
>> watchdog_device *wdev, unsigned int time
>>  	 * to reset the module) so that it is updated with new timeout
>> values.
>>  	 */
>>  	if (watchdog_active(wdev)) {
>> -		rzg2l_wdt_stop(wdev);
>> +		ret = rzg2l_wdt_stop(wdev);
>> +		if (ret)
>> +			return ret;
>> +
>>  		ret = rzg2l_wdt_start(wdev);
>>  	}
>>
>> --
>> 2.39.2
>