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

Jason Gunthorpe
2022-11-23T17:55:53Z

On Wed, Nov 23, 2022 at 05:49:36PM +0000, Matthew Wilcox wrote:
> 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 ;-)

Aside from less letters, is their another benifit to using *(in) ?

Jason