netdev - Re: [Patch net] net_sched: refetch skb protocol for each filter

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Message-ID: <CAM_iQpXA_jjvkPMGj1kH71jX--6dmfm+yktoeTXxzh6H=8C4yA@mail.gmail.com>
Date:   Mon, 14 Jan 2019 11:55:49 -0800
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     Daniel Borkmann <daniel@...earbox.net>
Cc:     Linux Kernel Network Developers <netdev@...r.kernel.org>,
        Martin Olsson <martin.olsson+netdev@...torsecurity.com>,
        Jamal Hadi Salim <jhs@...atatu.com>,
        Jiri Pirko <jiri@...nulli.us>
Subject: Re: [Patch net] net_sched: refetch skb protocol for each filter

On Mon, Jan 14, 2019 at 1:23 AM Daniel Borkmann <daniel@...earbox.net> wrote:
> Can't we do something like the below instead? Otherwise we'll needlessly refetch
> protocol every time there is a mismatch in above tp->protocol check as well.

Does this save anything given the fact we simply return if err>=0?

The protocol must be fetched, either before the loop or inside the loop, before
this "if err>=0". If we return, it won't be refetched even with my
patch. If we don't,
it has to be refetched again. So, I don't see any difference here.