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From: Stanislav Fomichev <sdf@fomichev.me>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Stanislav Fomichev <sdf@google.com>,
	netdev@vger.kernel.org, bpf@vger.kernel.org, davem@davemloft.net,
	ast@kernel.org, daniel@iogearbox.net, simon.horman@netronome.com,
	willemb@google.com, peterpenkov96@gmail.com
Subject: Re: [RFC bpf-next v3 6/8] flow_dissector: handle no-skb use case
Date: Sat, 23 Mar 2019 09:05:31 -0700	[thread overview]
Message-ID: <20190323160531.GZ7431@mini-arch.hsd1.ca.comcast.net> (raw)
In-Reply-To: <20190323014101.mxeey4tw3gt7o4yi@ast-mbp.dhcp.thefacebook.com>

On 03/22, Alexei Starovoitov wrote:
> On Fri, Mar 22, 2019 at 06:19:57PM -0700, Stanislav Fomichev wrote:
> > Are we ok with breaking api in this case? I'm all in on removing this
> > extra information. We can always put it back if somebody complains (and
> > manually parse in eth_get_headlen case).
> 
> Fine. That seems to be the only way forward to clean it all up.
> Could you submit patch 1 to bpf tree disallowing vlan fields?
> Patch 3 looks like candidate as well?
SGTM, will do. Let me also spend some time and do a simple test for
the vlan case, to make sure I didn't miss something important.
One question here though: would I need to wait for bpf and bpf-next
to re-merge to continues the series? Or we can cherry-pick those
patches to bpf-next as well (and git will work it out during the
merge)?

> > We can still have protocol, because in both skb/skb-less cases we have
> > it.
> 
> proto can work in both cases, but is it needed ? Does program benefit from it?
> The kernel side burns extra bytes by copying it and extra branches to handle it.
> May be drop it as well?
I feel like the program benefits from it, there is no need to go back and
re-parse that (and in the skb case, this data is already pulled). I was
also thinking about re-purposing flow_keys->n_proto for that (instead
of skb->protocol), so it functions as input and output, maybe that's a
more clear way to do it.

  reply	other threads:[~2019-03-23 16:05 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-22 19:58 [RFC bpf-next v3 0/8] net: flow_dissector: trigger BPF hook when called from eth_get_headlen Stanislav Fomichev
2019-03-22 19:58 ` [RFC bpf-next v3 1/8] flow_dissector: allow access only to a subset of __sk_buff fields Stanislav Fomichev
2019-03-22 19:58 ` [RFC bpf-next v3 2/8] flow_dissector: switch kernel context to struct bpf_flow_dissector Stanislav Fomichev
2019-03-22 19:58 ` [RFC bpf-next v3 3/8] flow_dissector: fix clamping of BPF flow_keys for non-zero nhoff Stanislav Fomichev
2019-03-22 19:58 ` [RFC bpf-next v3 4/8] bpf: when doing BPF_PROG_TEST_RUN for flow dissector use no-skb mode Stanislav Fomichev
2019-03-22 19:59 ` [RFC bpf-next v3 5/8] net: plumb network namespace into __skb_flow_dissect Stanislav Fomichev
2019-03-22 19:59 ` [RFC bpf-next v3 6/8] flow_dissector: handle no-skb use case Stanislav Fomichev
2019-03-23  1:00   ` Alexei Starovoitov
2019-03-23  1:19     ` Stanislav Fomichev
2019-03-23  1:41       ` Alexei Starovoitov
2019-03-23 16:05         ` Stanislav Fomichev [this message]
2019-03-26  0:35           ` Alexei Starovoitov
2019-03-26 16:45             ` Stanislav Fomichev
2019-03-26 17:48               ` Alexei Starovoitov
2019-03-26 17:51                 ` Willem de Bruijn
2019-03-26 18:08                   ` Alexei Starovoitov
2019-03-26 18:17                     ` Stanislav Fomichev
2019-03-26 18:30                       ` Alexei Starovoitov
2019-03-26 18:54                         ` Stanislav Fomichev
2019-03-27  1:41                           ` Alexei Starovoitov
2019-03-27  2:44                             ` Stanislav Fomichev
2019-03-27 17:55                               ` Alexei Starovoitov
2019-03-27 19:58                                 ` Stanislav Fomichev
2019-03-28  1:26                                   ` Alexei Starovoitov
2019-03-28  3:14                                     ` Willem de Bruijn
2019-03-28  3:32                                       ` Alexei Starovoitov
2019-03-28  4:17                                         ` Stanislav Fomichev
2019-03-28 12:58                                           ` Willem de Bruijn
2019-04-01 16:30                                             ` Stanislav Fomichev
2019-03-22 19:59 ` [RFC bpf-next v3 7/8] net: pass net argument to the eth_get_headlen Stanislav Fomichev
2019-03-22 19:59 ` [RFC bpf-next v3 8/8] selftests/bpf: add flow dissector bpf_skb_load_bytes helper test Stanislav Fomichev

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