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Date:   Wed, 29 Sep 2021 10:48:56 -0700
From:   Jakub Kicinski <kuba@kernel.org>
To:     Toke =?UTF-8?B?SMO4aWxhbmQtSsO4cmdlbnNlbg==?= <toke@redhat.com>
Cc:     Lorenz Bauer <lmb@cloudflare.com>,
        John Fastabend <john.fastabend@gmail.com>,
        Alexei Starovoitov <alexei.starovoitov@gmail.com>,
        Lorenzo Bianconi <lorenzo@kernel.org>,
        bpf <bpf@vger.kernel.org>,
        Network Development <netdev@vger.kernel.org>,
        Lorenzo Bianconi <lorenzo.bianconi@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>, shayagr@amazon.com,
        David Ahern <dsahern@kernel.org>,
        Jesper Dangaard Brouer <brouer@redhat.com>,
        Eelco Chaudron <echaudro@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        Alexander Duyck <alexander.duyck@gmail.com>,
        Saeed Mahameed <saeed@kernel.org>,
        "Fijalkowski, Maciej" <maciej.fijalkowski@intel.com>,
        "Karlsson, Magnus" <magnus.karlsson@intel.com>,
        tirthendu.sarkar@intel.com
Subject: Re: [PATCH v14 bpf-next 00/18] mvneta: introduce XDP multi-buffer
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On Wed, 29 Sep 2021 14:25:09 +0200 Toke H=C3=B8iland-J=C3=B8rgensen wrote:
> >> I guess we could play some trickery with stuffing offset/len/flags into
> >> one or two u64s to save an argument or two? =20
> >
> > Adding another pointer arg seems really hard to explain as an API.
> > What happens if I pass the "wrong" ptr? What happens if I pass NULL?
> >
> > How about this: instead of taking stack_ptr, take the return value
> > from header_pointer as an argument. =20
>=20
> Hmm, that's a good point; I do think that passing the return value from
> header pointer is more natural as well (you're flushing pointer you just
> wrote to, after all).

It is more natural but doesn't allow for the same level of optimization.
Wouldn't consistent naming obviate the semantics?