Re: [PATCH v2 1/3] pwm: Add pwm_cansleep() as exported API to users

[Florian Vaussard]

Le 28/01/2013 10:57, Thierry Reding a Ãcrit :
> On Mon, Jan 28, 2013 at 10:36:07AM +0100, Florian Vaussard wrote:
> > Hello,
> >
> > Le 28/01/2013 09:45, Peter Ujfalusi a Ãcrit :
> > > hi Thierry,
> > >
> > > On 01/26/2013 06:40 AM, Thierry Reding wrote:
> [...]
> > > > > +{
> > > > > +	return pwm->chip->can_sleep;
> > > > > +}
> > > > > +EXPORT_SYMBOL_GPL(pwm_cansleep);
> > > >
> > > > Would it make sense to check for NULL pointers here? I guess that
> > > > passing NULL into the function could be considered a programming error
> > > > and an oops would be okay, but in that case there's no point in making
> > > > the function return an int. Also see my next comment.
> > >
> > > While it is unlikely to happen it is better to be safe, something like this
> > > will do:
> > >
> > > return pwm ? pwm->chip->can_sleep : 0;
> >
> > Ok. And what about:
> >
> > BUG_ON(pwm == NULL);
> > return pwm->chip->can_sleep;
>
> I don't think we need that. In case pwm == NULL, dereferencing it will
> oops anyway. So either we make it safe and return an error code, or we
> let it oops without explicit BUG_ON().

Calling this function with a NULL pointer is a programming error, so there
is no error codes for such errors. I propose to return bool, and let it
oops if such case happens.

Regards,

Florian
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