On Tue, Jul 19, 2022 at 03:24:18PM +0200, Kumar Kartikeya Dwivedi wrote: > > +#define ____BTF_ID_FLAGS_LIST(_0, _1, _2, _3, _4, _5, N, ...) _1##_##_2##_##_3##_##_4##_##_5##__ > +#define __BTF_ID_FLAGS_LIST(...) ____BTF_ID_FLAGS_LIST(0x0, ##__VA_ARGS__, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0) > + > +#define __FLAGS(prefix, ...) \ > + __PASTE(prefix, __BTF_ID_FLAGS_LIST(__VA_ARGS__)) > + > +#define BTF_ID_FLAGS(prefix, name, ...) \ > + BTF_ID(prefix, name) \ > + __BTF_ID(__ID(__FLAGS(__BTF_ID__flags__, ##__VA_ARGS__))) > + > /* > * The BTF_ID_LIST macro defines pure (unsorted) list > * of BTF IDs, with following layout: > @@ -145,10 +164,53 @@ asm( \ > ".popsection; \n"); \ > extern struct btf_id_set name; > > +/* > + * The BTF_SET8_START/END macros pair defines sorted list of > + * BTF IDs and their flags plus its members count, with the > + * following layout: > + * > + * BTF_SET8_START(list) > + * BTF_ID_FLAGS(type1, name1, flags...) > + * BTF_ID_FLAGS(type2, name2, flags...) > + * BTF_SET8_END(list) > + * > + * __BTF_ID__set8__list: > + * .zero 8 > + * list: > + * __BTF_ID__type1__name1__3: > + * .zero 4 > + * __BTF_ID__flags__0x0_0x0_0x0_0x0_0x0__4: > + * .zero 4 Overall looks great, but why encode flags into a name? Why reuse ____BTF_ID for flags and complicate resolve_btfid? Instead of .zero 4 insert the actual flags as .word ? The usage will be slightly different. Instead of: BTF_ID_FLAGS(func, bpf_get_task_pid, KF_ACQUIRE, KF_RET_NULL) it will be BTF_ID_FLAGS(func, bpf_get_task_pid, KF_ACQUIRE | KF_RET_NULL)
