netdev - Re: [PATCH v5 bpf-next 2/2] net: xdp: introduce xdp_prepare

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAJ0CqmVsr=cv+0ndg3g4RDqVmKt=X6qQ7sbArNVrB+98e_3Sag@mail.gmail.com>
Date:   Tue, 29 Dec 2020 19:09:41 +0100
From:   Lorenzo Bianconi <lorenzo.bianconi@...hat.com>
To:     Daniel Borkmann <daniel@...earbox.net>
Cc:     Lorenzo Bianconi <lorenzo@...nel.org>,
        BPF-dev-list <bpf@...r.kernel.org>,
        Network Development <netdev@...r.kernel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Jesper Brouer <brouer@...hat.com>,
        Alexander Duyck <alexander.duyck@...il.com>,
        Maciej Fijalkowski <maciej.fijalkowski@...el.com>,
        Saeed Mahameed <saeed@...nel.org>
Subject: Re: [PATCH v5 bpf-next 2/2] net: xdp: introduce xdp_prepare_buff
 utility routine

> > +                     hard_start = page_address(rx_buffer->page) +
> > +                                  rx_buffer->page_offset - offset;
> > +                     xdp_prepare_buff(&xdp, hard_start, offset, size, true);
> >   #if (PAGE_SIZE > 4096)
> >                       /* At larger PAGE_SIZE, frame_sz depend on len size */
> >                       xdp.frame_sz = ixgbevf_rx_frame_truesize(rx_ring, size);

Hi Daniel,

thx for the review.

> [...]
> The design is very similar for most of the Intel drivers. Why the inconsistency on
> ice driver compared to the rest, what's the rationale there to do it in one but not
> the others? Generated code better there?

I applied the same logic for the ice driver but the code is just
slightly different.

>
> Couldn't you even move the 'unsigned int offset = xyz_rx_offset(rx_ring)' out of the
> while loop altogether for all of them? (You already use the xyz_rx_offset() implicitly
> for most of them when setting xdp.frame_sz.)
>

We discussed moving "offset = xyz_rx_offset(rx_ring)" out of the while
loop before but Saeed asked to address it in a dedicated series since
it is a little bit out of the scope. I have no strong opinion on it,
do you prefer to address it directly here?

Regards,
Lorenzo

> Thanks,
> Daniel
>