Re: [PATCH v5 4/6] media: v4l2-subdev: Assume V4L2_SUBDEV_API is selected

[Jacopo Mondi <jacopo@jmondi.org>]

Hi Sakari

On Wed, Apr 29, 2020 at 11:27:37AM +0300, Sakari Ailus wrote:
> Hi Jacopo,
>
> On Wed, Apr 29, 2020 at 09:02:15AM +0200, Jacopo Mondi wrote:
> > Hi Sakari,
> >
> > On Wed, Apr 29, 2020 at 12:26:43AM +0300, Sakari Ailus wrote:
> > > Hi Jacopo,
> > >
> > > On Tue, Apr 28, 2020 at 11:06:07PM +0200, Jacopo Mondi wrote:
> > > > A sub-device device node can be registered in user space only if the
> > > > CONFIG_V4L2_SUBDEV_API Kconfig option is selected.
> > > >
> > > > Remove checks from the v4l2-subdev file handle open/close functions and
> > > > ioctl handler as they are only accessible if a device node was registered
> > > > to user space in first place.
> > >
> > > Is there other motivation with this than clean up things a little?
> > >
> >
> > I had to add yet-another #if defined and I got fed up. If you don't
> > have a device node registered you won't be able to access any of the
> > functions where the existing #if defined() where placed.
> >
> > > The change increases the binary size marginally if the Kconfig option is
> > > disabled.
> > >
> >
> > I see. Should we instead guard the whole file handle operations and
> > ioctl handler instead of having #if defined() spread inside them ? I
> > assume they where there as leftover, as I'm still missing the point,
> > give that, as said, without V4L2_SUBDEV_API, you can't register any
> > device node to userspace..
>
> I think that's why those #ifdefs have been originally put there --- it's
> just dead code without the subdev nodes, and the compiler won't be able to
> figure this out.
>
> But it seems, later on, when people have added code that supports
> sub-device nodes, no #ifdefs have been added.
>
> I think I'd make sense to remove the current #ifdefs and add dummy ops for
> everything where needed that truly depends on that Kconfig option (i.e.
> sub-device nodes). Or just to remove these, as your patch does. It's not a
> lot of code.

that's what I've done now, as soon as I've run a few compile test, I'll send
a new version.

Thanks
   j

>
> --
> Kind regards,
>
> Sakari Ailus