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

[Martin KaFai Lau <martin.lau@xxxxxxxxx>]

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.