Re: [PATCH v21 net-next 1/6] sched: Struct definition and parsing of dualpi2 qdisc

[Jakub Kicinski <kuba@kernel.org>]

On Wed, 9 Jul 2025 08:17:08 +0000 Chia-Yu Chang (Nokia) wrote:
> Thanks for clarification, then I will add one extra "int opt_flag = 0" and set the flag (e.g., opt_flag += 1 << TCA_DUALPI2_LIMIT).
> 
> At the end will return an error message if no flag is set, like below example:
> 
> if (!opt_flag) {
>         sch_tree_unlock(sch);
>         NL_SET_ERR_MSG_MOD(extack, "Dualpi2 options are empty");
>         return -EINVAL;
> }
> 
> Or is there any other suggested ways to do it, please let me know, thanks.

You don't have to track each option. I think it's enough to check if
the option nest is empty:

-	if (!opt) {
+	if (!opt || !nla_len(opt)) {