Re: [RFC PATCH bpf-next v2 3/9] bpf: Replace RET_XXX_OR_NULL with RET_XXX | PTR_MAYBE_NULL

[Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx>]

On Mon, Nov 29, 2021 at 05:29:42PM -0800, Hao Luo wrote:
>  	/* update return register (already marked as written above) */
> -	if (fn->ret_type == RET_INTEGER) {
> +	ret_type = fn->ret_type;
> +	if (ret_type == RET_INTEGER) {
>  		/* sets type to SCALAR_VALUE */
>  		mark_reg_unknown(env, regs, BPF_REG_0);
> -	} else if (fn->ret_type == RET_VOID) {
> +	} else if (ret_type == RET_VOID) {
>  		regs[BPF_REG_0].type = NOT_INIT;
> -	} else if (fn->ret_type == RET_PTR_TO_MAP_VALUE_OR_NULL ||
> -		   fn->ret_type == RET_PTR_TO_MAP_VALUE) {
> +	} else if (BPF_BASE_TYPE(ret_type) == RET_PTR_TO_MAP_VALUE) {
>  		/* There is no offset yet applied, variable or fixed */
>  		mark_reg_known_zero(env, regs, BPF_REG_0);
>  		/* remember map_ptr, so that check_map_access()
> @@ -6530,28 +6536,27 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
>  		}
>  		regs[BPF_REG_0].map_ptr = meta.map_ptr;
>  		regs[BPF_REG_0].map_uid = meta.map_uid;
> -		if (fn->ret_type == RET_PTR_TO_MAP_VALUE) {
> +		if (ret_type_may_be_null(fn->ret_type)) {

it should have been ret_type here?

> +			regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL;
> +		} else {
>  			regs[BPF_REG_0].type = PTR_TO_MAP_VALUE;