netdev - Re: [PATCH v14 bpf-next 00/18] mvneta: introduce XDP multi-buffer support

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: <87mtnvi0bc.fsf@toke.dk>
Date:   Wed, 29 Sep 2021 22:39:03 +0200
From:   Toke Høiland-Jørgensen <toke@...hat.com>
To:     Jakub Kicinski <kuba@...nel.org>,
        Alexei Starovoitov <alexei.starovoitov@...il.com>
Cc:     Lorenz Bauer <lmb@...udflare.com>,
        Lorenzo Bianconi <lorenzo@...nel.org>,
        bpf <bpf@...r.kernel.org>, Networking <netdev@...r.kernel.org>,
        Lorenzo Bianconi <lorenzo.bianconi@...hat.com>,
        "David S . Miller" <davem@...emloft.net>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>, shayagr@...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>,
        Alexander Duyck <alexander.duyck@...il.com>,
        Saeed Mahameed <saeed@...nel.org>,
        Maciej Fijalkowski <maciej.fijalkowski@...el.com>,
        "Karlsson, Magnus" <magnus.karlsson@...el.com>,
        tirthendu.sarkar@...el.com
Subject: Re: [PATCH v14 bpf-next 00/18] mvneta: introduce XDP multi-buffer
 support

Jakub Kicinski <kuba@...nel.org> writes:

> On Wed, 29 Sep 2021 11:54:46 -0700 Alexei Starovoitov wrote:
>> I'm missing something. Why do we need a separate flush() helper?
>> Can't we do:
>> char buf[64], *p;
>> p = xdp_mb_pointer(ctx, flags, off, len, buf);
>> read/write p[]
>> if (p == buf)
>>     xdp_store_bytes(ctx, off, buf, len, flags);
>
> Sure we can. That's what I meant by "leave the checking to the program".
> It's bike shedding at this point.

Yeah, let's discuss the details once we have a patch :)

-Toke