From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Jakub Kicinski <kubakici@wp.pl>
Cc: Michael Chan <michael.chan@broadcom.com>,
davem@davemloft.net, netdev@vger.kernel.org,
Martin KaFai Lau <kafai@fb.com>
Subject: Re: [PATCH net-next v2 11/12] bnxt_en: Add basic XDP support.
Date: Thu, 2 Feb 2017 15:57:54 -0800 [thread overview]
Message-ID: <20170202235752.GA42563@ast-mbp.thefacebook.com> (raw)
In-Reply-To: <20170202150813.4d94b306@cakuba.netronome.com>
On Thu, Feb 02, 2017 at 03:08:27PM -0800, Jakub Kicinski wrote:
> > + rcu_read_lock();
> > + act = bpf_prog_run_xdp(xdp_prog, &xdp);
> > + rcu_read_unlock();
> > +
> > + if (orig_data != xdp.data) {
> > + offset = xdp.data - xdp.data_hard_start;
> > + len = xdp.data_end - xdp.data;
>
> If BPF changed the start of the packet and returned XDP_PASS you should
> make sure stack will see the modified packet. I.e. with adjusted
> offset and len.
that is correct.
skb passed to the stack should see new packet start and len.
Though today it's only useful with tc+cls_bpf on top that can
take advantage of it. Certainly more work is needed in this area
for xdp overall. I don't think we should mix that discussion
with this patch set.
next prev parent reply other threads:[~2017-02-02 23:57 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-02 16:55 [PATCH net-next v2 00/12] bnxt_en: Add XDP support Michael Chan
2017-02-02 16:55 ` [PATCH net-next v2 01/12] bnxt_en: Refactor rx SKB function Michael Chan
2017-02-02 22:56 ` Jakub Kicinski
2017-02-02 23:40 ` Michael Chan
2017-02-03 0:22 ` Jakub Kicinski
2017-02-03 0:34 ` Michael Chan
2017-02-02 16:55 ` [PATCH net-next v2 02/12] bnxt_en: Don't use DEFINE_DMA_UNMAP_ADDR to store DMA address in RX path Michael Chan
2017-02-02 16:55 ` [PATCH net-next v2 03/12] bnxt_en: Add bp->rx_dir field for rx buffer DMA direction Michael Chan
2017-02-02 16:55 ` [PATCH net-next v2 04/12] bnxt_en: Parameterize RX buffer offsets Michael Chan
2017-02-02 16:55 ` [PATCH net-next v2 05/12] bnxt_en: Add RX page mode support Michael Chan
2017-02-02 16:55 ` [PATCH net-next v2 06/12] bnxt_en: Use event bit map in RX path Michael Chan
2017-02-02 16:55 ` [PATCH net-next v2 07/12] bnxt_en: Centralize logic to reserve rings Michael Chan
2017-02-02 16:55 ` [PATCH net-next v2 08/12] bnxt_en: Add tx ring mapping logic Michael Chan
2017-02-02 16:55 ` [PATCH net-next v2 09/12] bnxt_en: Add a set of TX rings to support XDP Michael Chan
2017-02-02 16:55 ` [PATCH net-next v2 10/12] bnxt_en: Refactor tx completion path Michael Chan
2017-02-02 16:55 ` [PATCH net-next v2 11/12] bnxt_en: Add basic XDP support Michael Chan
2017-02-02 17:18 ` Mintz, Yuval
2017-02-02 21:30 ` Michael Chan
2017-02-02 23:08 ` Jakub Kicinski
2017-02-02 23:57 ` Alexei Starovoitov [this message]
2017-02-02 16:55 ` [PATCH net-next v2 12/12] bnxt_en: Add support for XDP_TX action Michael Chan
2017-02-03 20:49 ` [PATCH net-next v2 00/12] bnxt_en: Add XDP support David Miller
2017-02-03 21:13 ` Michael Chan
2017-02-03 21:50 ` David Miller
2017-02-03 21:58 ` Tom Herbert
2017-02-03 22:02 ` David Miller
2017-02-03 22:25 ` Tom Herbert
2017-02-03 22:29 ` David Miller
2017-02-04 0:33 ` Jakub Kicinski
2017-02-04 1:32 ` Michael Chan
2017-02-04 1:41 ` Jakub Kicinski
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