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

Matthew Wilcox
2022-11-23T17:49:56Z

On Wed, Nov 23, 2022 at 01:29:56PM -0400, Jason Gunthorpe wrote:
> #define generic_container_of(in_type, in, out_type, out_member) \
> _Generic(in, \
> const in_type *: ((const out_type *)container_of(in, out_type, out_member)), \
> in_type *: ((out_type *)container_of(in, out_type, out_member)) \
> )

There's a neat trick I found in seqlock.h:

#define generic_container_of(in_t, in, out_t, m) \
_Generic(*(in), \
const in_t: ((const out_t *)container_of(in, out_t, m)), \
in_t: ((out_t *)container_of(in, out_type, m)) \
)

and now it fits in 80 columns ;-)

> #define kobj_to_dev(__kobj) \
> generic_container_of(struct kobject, __kobj, struct device, kobj)
>
> Jason