bpf: Drop reg_type_may_be_refcounted_or_null

It is not scalable to maintain a list of types that can have non-zero
ref_obj_id. It is never set for scalars anyway, so just remove the
conditional on register types and print it whenever it is non-zero.
Acked-by: NDave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: NKumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: NDavid Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20221103191013.1236066-6-memxor@gmail.comSigned-off-by: NAlexei Starovoitov <ast@kernel.org>

kernel/bpf/verifier.c

@@ -457,13 +457,6 @@ static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg)
 		map_value_has_spin_lock(reg->map_ptr);
 }
 
-static bool reg_type_may_be_refcounted_or_null(enum bpf_reg_type type)
-{
-	type = base_type(type);
-	return type == PTR_TO_SOCKET || type == PTR_TO_TCP_SOCK ||
-		type == PTR_TO_MEM || type == PTR_TO_BTF_ID;
-}
-
 static bool type_is_rdonly_mem(u32 type)
 {
 	return type & MEM_RDONLY;
@@ -875,7 +868,7 @@ static void print_verifier_state(struct bpf_verifier_env *env,
 
 			if (reg->id)
 				verbose_a("id=%d", reg->id);
-			if (reg_type_may_be_refcounted_or_null(t) && reg->ref_obj_id)
+			if (reg->ref_obj_id)
 				verbose_a("ref_obj_id=%d", reg->ref_obj_id);
 			if (t != SCALAR_VALUE)
 				verbose_a("off=%d", reg->off);