From: Lorenzo Bianconi <lorenzo@kernel.org>
To: Jakub Kicinski <kuba@kernel.org>
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, davem@davemloft.net,
ast@kernel.org, daniel@iogearbox.net, brouer@redhat.com,
toke@redhat.com, pabeni@redhat.com, echaudro@redhat.com,
lorenzo.bianconi@redhat.com, toshiaki.makita1@gmail.com,
andrii@kernel.org
Subject: Re: [PATCH bpf-next 2/3] veth: rework veth_xdp_rcv_skb in order to accept non-linear skb
Date: Mon, 14 Feb 2022 22:03:34 +0100 [thread overview]
Message-ID: <YgrDppq+PRD7j/C8@lore-desk> (raw)
In-Reply-To: <20220214074824.370d7ae6@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
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> On Sat, 12 Feb 2022 12:03:49 +0100 Lorenzo Bianconi wrote:
> > On Feb 11, Jakub Kicinski wrote:
> > > On Fri, 11 Feb 2022 02:20:31 +0100 Lorenzo Bianconi wrote:
> > > > + if (skb_shared(skb) || skb_head_is_locked(skb)) {
> > >
> > > Is this sufficient to guarantee that the frags can be written?
> > > skb_cow_data() tells a different story.
> >
> > Do you mean to consider paged part of the skb always not writable, right?
> > In other words, we should check something like:
> >
> > if (skb_shared(skb) || skb_head_is_locked(skb) ||
> > skb_shinfo(skb)->nr_frags) {
> > ...
> > }
>
> Yes, we do have skb_has_shared_frag() but IDK if it guarantees frags
> are writable :S
ack, I will add skb_shinfo(skb)->nr_frags check in v2.
Regards,
Lorenzo
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next prev parent reply other threads:[~2022-02-14 21:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-11 1:20 [PATCH bpf-next 0/3] introduce xdp frags support to veth driver Lorenzo Bianconi
2022-02-11 1:20 ` [PATCH bpf-next 1/3] net: veth: account total xdp_frame len running ndo_xdp_xmit Lorenzo Bianconi
2022-02-11 1:20 ` [PATCH bpf-next 2/3] veth: rework veth_xdp_rcv_skb in order to accept non-linear skb Lorenzo Bianconi
2022-02-12 1:04 ` Jakub Kicinski
2022-02-12 11:03 ` Lorenzo Bianconi
2022-02-14 15:48 ` Jakub Kicinski
2022-02-14 21:03 ` Lorenzo Bianconi [this message]
2022-02-11 1:20 ` [PATCH bpf-next 3/3] veth: allow jumbo frames in xdp mode Lorenzo Bianconi
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