Re: [PATCH v2 04/11] watchdog: rzg2l_wdt: Check return status of pm_runtime_put()

[Guenter Roeck]

On 1/31/24 03:00, claudiu beznea wrote:
> On 31.01.2024 12:41, Biju Das wrote:
> > Hi Claudiu,
> >
> > > -----Original Message-----
> > > From: claudiu beznea <claudiu.beznea@xxxxxxxxx>
> > > Sent: Wednesday, January 31, 2024 10:36 AM
> > > 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@xxxxxxxxx>
> > > > > 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@xxxxxxxxxxxxxx>
> > > > >
> > > > > 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@xxxxxxxxxxxxxx>
> > > > > ---
> > > > >
> > > > > 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:
> >
> > Oops, I missed that discussion. Out of curiosity,
> > What watchdog framework/consumer is going to do with a
> > Non-error return value of 1?
>
> Looking at this:
> https://elixir.bootlin.com/linux/latest/source/drivers/watchdog/watchdog_dev.c#L809
>
> it seems that the positive values are not considered errors thus, indeed,
> we may return directly:
>
> return pm_runtime_put();
>
> Guenter,
>
> With this (and previous discussion from [1]), are you OK to change it like:
>
> return pm_runtime_put();

Instead of looking at the source, I would kindly ask you to look at the API.

Guenter