From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jamal Hadi Salim <jhs@mojatatu.com>
Subject: Re: [PATCH net-next v3 5/5] act_mirred: use TC_ACT_REINJECT when
 possible
Date: Wed, 25 Jul 2018 07:50:51 -0400
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 <CAM_iQpUiH5gdPp_=GKhP7N8Eu2VVjmGfR6hvXQoaKwyot0JkjQ@mail.gmail.com>
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Cc: Linux Kernel Network Developers <netdev@vger.kernel.org>,
        Jiri Pirko <jiri@resnulli.us>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>,
        Eyal Birger <eyal.birger@gmail.com>,
        David Miller <davem@davemloft.net>
To: Cong Wang <xiyou.wangcong@gmail.com>,
        Paolo Abeni <pabeni@redhat.com>
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On 24/07/18 05:15 PM, Cong Wang wrote:
> On Tue, Jul 24, 2018 at 1:07 PM Paolo Abeni <pabeni@redhat.com> wrote:
>> +
>> +               /* let's the caller reinject the packet, if possible */
>> +               if (skb_at_tc_ingress(skb)) {
>> +                       res->ingress = want_ingress;
>> +                       res->qstats = this_cpu_ptr(m->common.cpu_qstats);
>> +                       return TC_ACT_REINJECT;
>> +               }
> 
> Looks good to me, but here we no longer return user-specified
> return value here, I am sure it is safe for TC_ACT_STOLEN, but
> I am not sure if it is safe for other values, like TC_ACT_RECLASSIFY.
> 
> Jamal, is there any use case of returning !TC_ACT_STOLEN for
> ingress redirections?

I cant think of one off top of my head.
There maybe a future use case where it is not so - maybe just allow
to return the user programmed action? that value will always be
TC_ACT_STOLEN if the rule was specified via iproute2/tc.

cheers,
jamal