Re: [PATCH bpf-next v4 3/6] libbpf: Convert st_ops->data to shadow type.

[Kui-Feng Lee <sinquersw@gmail.com>]

On 2/26/24 14:57, Martin KaFai Lau wrote:
> On 2/22/24 2:26 PM, thinker.li@gmail.com wrote:
>> +/* Convert the data of a struct_ops map to shadow type.
>> + *
>> + * The function pointers are replaced with the pointers of 
>> bpf_program in
>> + * st_ops->progs[].
>> + */
>> +static void struct_ops_convert_shadow(struct bpf_map *map,
>> +                      const struct btf_type *t)
>> +{
>> +    struct btf *btf = map->obj->btf;
>> +    struct bpf_struct_ops *st_ops = map->st_ops;
>> +    const struct btf_member *m;
>> +    const struct btf_type *mtype;
>> +    char *data;
>> +    int i;
>> +
>> +    data = st_ops->data;
>> +
>> +    for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) {
>> +        mtype = skip_mods_and_typedefs(btf, m->type, NULL);
>> +
>> +        if (btf_kind(mtype) != BTF_KIND_PTR)
>> +            continue;
>> +        if (!resolve_func_ptr(btf, m->type, NULL))
>> +            continue;
>> +
>> +        *((struct bpf_program **)(data + m->offset / 8)) =
>> +            st_ops->progs[i];
> 
> This is to initialize the bpf_program pointer in the st_ops->data.
> Can this be done directly at the bpf_object__collect_st_ops_relos()?

No problem!

> 
>> +    }
>> +}
>> +
>