netdev - Re: [PATCH v9 bpf-next 02/14] xdp: introduce flags field in xdp_buff/xdp

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: <CAKgT0Ue7TsgwbQF+mfeDB-18Q-R29YZWe=y6Kgeg0xxbwds=vw@mail.gmail.com>
Date:   Mon, 28 Jun 2021 13:14:31 -0700
From:   Alexander Duyck <alexander.duyck@...il.com>
To:     Lorenzo Bianconi <lorenzo@...nel.org>
Cc:     bpf <bpf@...r.kernel.org>, Netdev <netdev@...r.kernel.org>,
        lorenzo.bianconi@...hat.com, David Miller <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>, shayagr@...zon.com,
        "Jubran, Samih" <sameehj@...zon.com>,
        John Fastabend <john.fastabend@...il.com>,
        David Ahern <dsahern@...nel.org>,
        Jesper Dangaard Brouer <brouer@...hat.com>,
        Eelco Chaudron <echaudro@...hat.com>,
        Jason Wang <jasowang@...hat.com>,
        Saeed Mahameed <saeed@...nel.org>,
        Maciej Fijalkowski <maciej.fijalkowski@...el.com>,
        "Karlsson, Magnus" <magnus.karlsson@...el.com>,
        Tirthendu <tirthendu.sarkar@...el.com>
Subject: Re: [PATCH v9 bpf-next 02/14] xdp: introduce flags field in xdp_buff/xdp_frame

On Mon, Jun 14, 2021 at 5:50 AM Lorenzo Bianconi <lorenzo@...nel.org> wrote:
>
> Introduce flags field in xdp_frame/xdp_buffer data structure
> to define additional buffer features. At the moment the only
> supported buffer feature is multi-buffer bit (mb). Multi-buffer bit
> is used to specify if this is a linear buffer (mb = 0) or a multi-buffer
> frame (mb = 1). In the latter case the shared_info area at the end of
> the first buffer will be properly initialized to link together
> subsequent buffers.
>
> Signed-off-by: Lorenzo Bianconi <lorenzo@...nel.org>

Instead of passing this between buffers and frames I wonder if this
wouldn't be better to place in something like the xdp_mem_info
structure since this is something that would be specific to how the
device is handling memory anyway. You could probably split the type
field into a 16b type and a 16b flags field. Then add your bit where 0
is linear/legacy and 1 is scatter-gather/multi-buffer.