Re: [PATCH v1] gpiolib: Don't WARN on gpiod_put() for optional GPIO

[Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>]

On Tue, Mar 26, 2019 at 09:44:20PM +0200, Andy Shevchenko wrote:
> On Tue, Mar 26, 2019 at 06:48:25PM +0100, Bartosz Golaszewski wrote:
> > wt., 26 mar 2019 o 16:21 Andy Shevchenko
> > <andriy.shevchenko@xxxxxxxxxxxxxxx> napisał(a):
> > >
> > > In case of debug and optional GPIO requested, the gpiod_put() is not aware of
> > > and will WARN, which is not the case.
> > >
> > > Make gpiod_put() NULL-aware to keep silent for optional GPIOs.
> > >
> > > Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> > > ---
> > >  drivers/gpio/gpiolib.c | 3 ++-
> > >  1 file changed, 2 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> > > index 144af0733581..36445e24ee89 100644
> > > --- a/drivers/gpio/gpiolib.c
> > > +++ b/drivers/gpio/gpiolib.c
> > > @@ -4616,7 +4616,8 @@ EXPORT_SYMBOL_GPL(gpiod_get_array_optional);
> > >   */
> > >  void gpiod_put(struct gpio_desc *desc)
> > >  {
> > > -       gpiod_free(desc);
> > > +       if (desc)
> > > +               gpiod_free(desc);
> > >  }
> > >  EXPORT_SYMBOL_GPL(gpiod_put);
> > >
> > > --
> > > 2.20.1
> > >
> > 
> > In that case I don't think we need to keep checking desc for NULL in
> > gpiod_free().
> 
> I didn't remove the check there because it's called more than just from
> gpiod_put(). I didn't check all code paths myself. So, if it seems good for you
> to remove the check I can do it in next version.

Any additional comments on this? I have looked briefly at this and found that
gpiod_free() is used to support legacy gpio_free() which is used in a plenty of
drivers. There are more than dozen are using non static number for these calls.

I think the patch as is is the best approach we can do right now.

-- 
With Best Regards,
Andy Shevchenko