Re: [PATCH bpf-next v5 7/9] libbpf: Find correct module BTFs for struct_ops maps and progs.

[Kui-Feng Lee <sinquersw@xxxxxxxxx>]

On 10/18/23 19:43, Martin KaFai Lau wrote:
> On 10/17/23 9:23 AM, thinker.li@xxxxxxxxx wrote:
> > -static int find_ksym_btf_id(struct bpf_object *obj, const char 
> > *ksym_name,
> > -                __u16 kind, struct btf **res_btf,
> > -                struct module_btf **res_mod_btf)
> > +static int find_module_btf_id(struct bpf_object *obj, const char 
> > *kern_name,
> > +                  __u16 kind, struct btf **res_btf,
> > +                  struct module_btf **res_mod_btf)
> >   {
> >       struct module_btf *mod_btf;
> >       struct btf *btf;
> > @@ -7710,7 +7728,7 @@ static int find_ksym_btf_id(struct bpf_object 
> > *obj, const char *ksym_name,
> >       btf = obj->btf_vmlinux;
> >       mod_btf = NULL;
> > -    id = btf__find_by_name_kind(btf, ksym_name, kind);
> > +    id = btf__find_by_name_kind(btf, kern_name, kind);
> >       if (id == -ENOENT) {
> >           err = load_module_btfs(obj);
> > @@ -7721,7 +7739,7 @@ static int find_ksym_btf_id(struct bpf_object 
> > *obj, const char *ksym_name,
> >               /* we assume module_btf's BTF FD is always >0 */
> >               mod_btf = &obj->btf_modules[i];
> >               btf = mod_btf->btf;
> > -            id = btf__find_by_name_kind_own(btf, ksym_name, kind);
> > +            id = btf__find_by_name_kind_own(btf, kern_name, kind);
> >               if (id != -ENOENT)
> >                   break;
> >           }
> > @@ -7744,7 +7762,7 @@ static int 
> > bpf_object__resolve_ksym_var_btf_id(struct bpf_object *obj,
> >       struct btf *btf = NULL;
> >       int id, err;
> > -    id = find_ksym_btf_id(obj, ext->name, BTF_KIND_VAR, &btf, &mod_btf);
> > +    id = find_module_btf_id(obj, ext->name, BTF_KIND_VAR, &btf, 
> > &mod_btf);
> >       if (id < 0) {
> >           if (id == -ESRCH && ext->is_weak)
> >               return 0;
> > @@ -7798,8 +7816,8 @@ static int 
> > bpf_object__resolve_ksym_func_btf_id(struct bpf_object *obj,
> >       local_func_proto_id = ext->ksym.type_id;
> > -    kfunc_id = find_ksym_btf_id(obj, ext->essent_name ?: ext->name, 
> > BTF_KIND_FUNC, &kern_btf,
> > -                    &mod_btf);
> > +    kfunc_id = find_module_btf_id(obj, ext->essent_name ?: ext->name, 
> > BTF_KIND_FUNC, &kern_btf,
> > +                      &mod_btf);
> >       if (kfunc_id < 0) {
> >           if (kfunc_id == -ESRCH && ext->is_weak)
> >               return 0;
> > @@ -9464,9 +9482,9 @@ static int libbpf_find_prog_btf_id(const char 
> > *name, __u32 attach_prog_fd)
> >       return err;
> >   }
> > -static int find_kernel_btf_id(struct bpf_object *obj, const char 
> > *attach_name,
> > -                  enum bpf_attach_type attach_type,
> > -                  int *btf_obj_fd, int *btf_type_id)
> > +static int find_kernel_attach_btf_id(struct bpf_object *obj, const 
> > char *attach_name,
> > +                     enum bpf_attach_type attach_type,
> > +                     int *btf_obj_fd, int *btf_type_id)
> >   {
> >       int ret, i;
> > @@ -9531,7 +9549,9 @@ static int libbpf_find_attach_btf_id(struct 
> > bpf_program *prog, const char *attac
> >           *btf_obj_fd = 0;
> >           *btf_type_id = 1;
> >       } else {
> > -        err = find_kernel_btf_id(prog->obj, attach_name, attach_type, 
> > btf_obj_fd, btf_type_id);
> > +        err = find_kernel_attach_btf_id(prog->obj, attach_name,
> > +                        attach_type, btf_obj_fd,
> > +                        btf_type_id);
> >       }
> >       if (err) {
> >           pr_warn("prog '%s': failed to find kernel BTF type ID of 
> > '%s': %d\n",
> > @@ -12945,9 +12965,9 @@ int bpf_program__set_attach_target(struct 
> > bpf_program *prog,
> >           err = bpf_object__load_vmlinux_btf(prog->obj, true);
> >           if (err)
> >               return libbpf_err(err);
> > -        err = find_kernel_btf_id(prog->obj, attach_func_name,
> > -                     prog->expected_attach_type,
> > -                     &btf_obj_fd, &btf_id);
> > +        err = find_kernel_attach_btf_id(prog->obj, attach_func_name,
> > +                        prog->expected_attach_type,
> > +                        &btf_obj_fd, &btf_id);
>
> Please avoid mixing this level of name changes with the main changes. It 
> is quite confusing for the reviewer and it is not mentioned in the 
> commit message either.

Got it! Sorry confusing.