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 ;-) Nice trick! Dropping the inline functions is a bit different, let me see if that still gives a sane error if we pass an incorrect type or mess with the const * the wrong way. I'll run some tests tomorrow afternoon... thanks, greg k-h
