Re: [PATCH bpf-next v1 1/8] bpf: Add BTF_ID_LIST_END and BTF_ID_LIST_SIZE macros

[Eduard Zingerman <eddyz87@gmail.com>]

On Wed, 2025-10-29 at 12:01 -0700, Ihor Solodrai wrote:
> Implement macros in btf_ids.h to enable a calculation of BTF_ID_LIST
> size. This is done by declaring an additional __end symbol which can
> then be used as an indicator of the end of an array.
> 
> Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
> ---
>  include/linux/btf_ids.h | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
> index 139bdececdcf..27a4724d5aa9 100644
> --- a/include/linux/btf_ids.h
> +++ b/include/linux/btf_ids.h
> @@ -97,6 +97,16 @@ asm(							\
>  __BTF_ID_LIST(name, local)				\
>  extern u32 name[];
>  
> +/*
> + * The BTF_ID_LIST_END macro may be used to denote an end
> + * of a BTF_ID_LIST. This enables calculation of the list
> + * size with BTF_ID_LIST_SIZE.
> + */
> +#define BTF_ID_LIST_END(name) \
> +BTF_ID_LIST(name##__end)
> +#define BTF_ID_LIST_SIZE(name) \
> +(name##__end - name)
> +

Nit: no need for line break?

  #define BTF_ID_LIST_SIZE(name) (name##__end - name)

>  #define BTF_ID_LIST_GLOBAL(name, n)			\
>  __BTF_ID_LIST(name, globl)
>