bpf: Move btf_resolve_size into __btf_resolve_size

Moving btf_resolve_size into __btf_resolve_size and
keeping btf_resolve_size public with just first 3
arguments, because the rest of the arguments are not
used by outside callers.

Following changes are adding more arguments, which
are not useful to outside callers. They will be added
to the __btf_resolve_size function.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200825192124.710397-4-jolsa@kernel.org

include/linux/btf.h

@@ -64,8 +64,7 @@ const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
 						 u32 id, u32 *res_id);
 const struct btf_type *
 btf_resolve_size(const struct btf *btf, const struct btf_type *type,
-		 u32 *type_size, const struct btf_type **elem_type,
-		 u32 *total_nelems);
+		 u32 *type_size);
 
 #define for_each_member(i, struct_type, member)			\
 	for (i = 0, member = btf_type_member(struct_type);	\

kernel/bpf/bpf_struct_ops.c

@@ -298,8 +298,7 @@ static int check_zero_holes(const struct btf_type *t, void *data)
 			return -EINVAL;
 
 		mtype = btf_type_by_id(btf_vmlinux, member->type);
-		mtype = btf_resolve_size(btf_vmlinux, mtype, &msize,
-					 NULL, NULL);
+		mtype = btf_resolve_size(btf_vmlinux, mtype, &msize);
 		if (IS_ERR(mtype))
 			return PTR_ERR(mtype);
 		prev_mend = moff + msize;
@@ -396,8 +395,7 @@ static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
 			u32 msize;
 
 			mtype = btf_type_by_id(btf_vmlinux, member->type);
-			mtype = btf_resolve_size(btf_vmlinux, mtype, &msize,
-						 NULL, NULL);
+			mtype = btf_resolve_size(btf_vmlinux, mtype, &msize);
 			if (IS_ERR(mtype)) {
 				err = PTR_ERR(mtype);
 				goto reset_unlock;

kernel/bpf/btf.c

@@ -1088,10 +1088,10 @@ static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
  * *elem_type: same as return type ("struct X")
  * *total_nelems: 1
  */
-const struct btf_type *
-btf_resolve_size(const struct btf *btf, const struct btf_type *type,
-		 u32 *type_size, const struct btf_type **elem_type,
-		 u32 *total_nelems)
+static const struct btf_type *
+__btf_resolve_size(const struct btf *btf, const struct btf_type *type,
+		   u32 *type_size, const struct btf_type **elem_type,
+		   u32 *total_nelems)
 {
 	const struct btf_type *array_type = NULL;
 	const struct btf_array *array;
@@ -1150,6 +1150,13 @@ btf_resolve_size(const struct btf *btf, const struct btf_type *type,
 	return array_type ? : type;
 }
 
+const struct btf_type *
+btf_resolve_size(const struct btf *btf, const struct btf_type *type,
+		 u32 *type_size)
+{
+	return __btf_resolve_size(btf, type, type_size, NULL, NULL);
+}
+
 /* The input param "type_id" must point to a needs_resolve type */
 static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
 						  u32 *type_id)
@@ -3976,8 +3983,8 @@ int btf_struct_access(struct bpf_verifier_log *log,
 		mtype = btf_type_by_id(btf_vmlinux, member->type);
 		mname = __btf_name_by_offset(btf_vmlinux, member->name_off);
 
-		mtype = btf_resolve_size(btf_vmlinux, mtype, &msize,
-					 &elem_type, &total_nelems);
+		mtype = __btf_resolve_size(btf_vmlinux, mtype, &msize,
+					   &elem_type, &total_nelems);
 		if (IS_ERR(mtype)) {
 			bpf_log(log, "field %s doesn't have size\n", mname);
 			return -EFAULT;
@@ -3991,7 +3998,7 @@ int btf_struct_access(struct bpf_verifier_log *log,
 		if (btf_type_is_array(mtype)) {
 			u32 elem_idx;
 
-			/* btf_resolve_size() above helps to
+			/* __btf_resolve_size() above helps to
 			 * linearize a multi-dimensional array.
 			 *
 			 * The logic here is treating an array