Re: [PATCH 3/5] driver core: make struct device_type.uevent() take a const *

Andy Shevchenko
2022-11-23T13:46:42Z

On Wed, Nov 23, 2022 at 02:14:31PM +0100, Maximilian Luz wrote:
> On 11/23/22 13:25, Greg Kroah-Hartman wrote:
> > The uevent() callback in struct device_type should not be modifying the
> > device that is passed into it, so mark it as a const * and propagate the
> > function signature changes out into all relevant subsystems that use
> > this callback.

[...]

> > -static inline struct ssam_device *to_ssam_device(struct device *d)
> > +static inline struct ssam_device *to_ssam_device(const struct device *d)
> > {
> > return container_of(d, struct ssam_device, dev);
> > }
>
> I am slightly conflicted about this change as that now more or less
> implicitly drops the const. So I'm wondering if it wouldn't be better to
> either create a function specifically for const pointers or to just
> open-code it in the instance above.
>
> I guess we could also convert this to a macro. Then at least there
> wouldn't be an explicit and potentially misleading const-conversion
> indicated in the function signature.

This is an intermediate step as far as I know since moving container_of to
recognize const is a bit noisy right now. I guess you can find a discussion
on the topic between Greg and Sakari.

--
With Best Regards,
Andy Shevchenko