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

[Guenter Roeck]

On 1/31/24 02:41, 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?

You mean what the watchdog subsystem does if a driver violates its API ?
That is undefined. The API says:

* start: this is a pointer to the routine that starts the watchdog timer
  device.
  The routine needs a pointer to the watchdog timer device structure as a
  parameter. It returns zero on success or a negative errno code for failure.
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

We are not going to change the API, if that is what you are suggesting.

Thanks,
Guenter