netdev - Re: [PATCH bpf-next v2] net, xdp: allow metadata

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Message-ID: <b6da9739-a6e6-4528-a4cd-f87e8e025740@intel.com>
Date: Fri, 3 Nov 2023 15:03:14 +0100
From: Alexander Lobakin <aleksander.lobakin@...el.com>
To: Larysa Zaremba <larysa.zaremba@...el.com>
CC: <bpf@...r.kernel.org>, <netdev@...r.kernel.org>, Alexei Starovoitov
	<ast@...nel.org>, Daniel Borkmann <daniel@...earbox.net>, "David S. Miller"
	<davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>, "Jesper Dangaard
 Brouer" <hawk@...nel.org>, Eric Dumazet <edumazet@...gle.com>, "Magnus
 Karlsson" <magnus.karlsson@...il.com>, Willem de Bruijn
	<willemdebruijn.kernel@...il.com>, Yunsheng Lin <linyunsheng@...wei.com>,
	Maciej Fijalkowski <maciej.fijalkowski@...el.com>, John Fastabend
	<john.fastabend@...il.com>
Subject: Re: [PATCH bpf-next v2] net, xdp: allow metadata > 32

From: Larysa Zaremba <larysa.zaremba@...el.com>
Date: Tue, 31 Oct 2023 18:57:37 +0100

It doesn't have "From: Alexa..." here, so that you'll be the author once
this is applied. Is this intended? ^.^

> 32 bytes may be not enough for some custom metadata. Relax the restriction,
> allow metadata larger than 32 bytes and make __skb_metadata_differs() work
> with bigger lengths.
> 
> Now size of metadata is only limited by the fact it is stored as u8
> in skb_shared_info, so the upper limit is now is 255. Other important
> conditions, such as having enough space for xdp_frame building, are already
> checked in bpf_xdp_adjust_meta().

[...]

Thanks,
Olek