netdev - Re: [patch net-next] net: sched: don't dump chains only held by actions

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Date:   Sat, 28 Jul 2018 10:39:36 -0700
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     Jiri Pirko <jiri@...nulli.us>
Cc:     Linux Kernel Network Developers <netdev@...r.kernel.org>,
        David Miller <davem@...emloft.net>,
        Jamal Hadi Salim <jhs@...atatu.com>,
        Jakub Kicinski <jakub.kicinski@...ronome.com>,
        mlxsw@...lanox.com
Subject: Re: [patch net-next] net: sched: don't dump chains only held by actions

On Sat, Jul 28, 2018 at 10:20 AM Cong Wang <xiyou.wangcong@...il.com> wrote:
>
> On Fri, Jul 27, 2018 at 12:47 AM Jiri Pirko <jiri@...nulli.us> wrote:
> >
> > From: Jiri Pirko <jiri@...lanox.com>
> >
> > In case a chain is empty and not explicitly created by a user,
> > such chain should not exist. The only exception is if there is
> > an action "goto chain" pointing to it. In that case, don't show the
> > chain in the dump. Track the chain references held by actions and
> > use them to find out if a chain should or should not be shown
> > in chain dump.
> >
> > Signed-off-by: Jiri Pirko <jiri@...lanox.com>
>
> Looks reasonable to me.
>
> Acked-by: Cong Wang <xiyou.wangcong@...il.com>

Hold on...

If you increase the refcnt for a zombie chain on NEWCHAIN path,
then it would become a non-zombie, this makes sense. However,
if the action_refcnt gets increased again when another action uses it,
it become a zombie again because refcnt==action_refcnt??