netdev - Re: [PATCH net-next 07/10] mlx5e: Call skb_metadata

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Message-ID: <873449wu80.fsf@cloudflare.com>
Date: Tue, 13 Jan 2026 13:52:15 +0100
From: Jakub Sitnicki <jakub@...udflare.com>
To: Tariq Toukan <ttoukan.linux@...il.com>
Cc: netdev@...r.kernel.org,  "David S. Miller" <davem@...emloft.net>,  Eric
 Dumazet <edumazet@...gle.com>,  Jakub Kicinski <kuba@...nel.org>,  Paolo
 Abeni <pabeni@...hat.com>,  Simon Horman <horms@...nel.org>,  Michael Chan
 <michael.chan@...adcom.com>,  Pavan Chebbi <pavan.chebbi@...adcom.com>,
  Andrew Lunn <andrew+netdev@...n.ch>,  Tony Nguyen
 <anthony.l.nguyen@...el.com>,  Przemek Kitszel
 <przemyslaw.kitszel@...el.com>,  Saeed Mahameed <saeedm@...dia.com>,  Leon
 Romanovsky <leon@...nel.org>,  Tariq Toukan <tariqt@...dia.com>,  Mark
 Bloch <mbloch@...dia.com>,  Alexei Starovoitov <ast@...nel.org>,  Daniel
 Borkmann <daniel@...earbox.net>,  Jesper Dangaard Brouer
 <hawk@...nel.org>,  John Fastabend <john.fastabend@...il.com>,  Stanislav
 Fomichev <sdf@...ichev.me>,  intel-wired-lan@...ts.osuosl.org,
  bpf@...r.kernel.org,  kernel-team@...udflare.com
Subject: Re: [PATCH net-next 07/10] mlx5e: Call skb_metadata_set when
 skb->data points past metadata

On Tue, Jan 13, 2026 at 08:08 AM +02, Tariq Toukan wrote:
> On 10/01/2026 23:05, Jakub Sitnicki wrote:
>> Prepare to copy the XDP metadata into an skb extension in skb_metadata_set.
>> Adjust the driver to pull from skb->data before calling skb_metadata_set.
>> Signed-off-by: Jakub Sitnicki <jakub@...udflare.com>
>> ---
>>   drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
>> b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
>> index 2b05536d564a..20c983c3ce62 100644
>> --- a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
>> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
>> @@ -237,8 +237,8 @@ static struct sk_buff *mlx5e_xsk_construct_skb(struct mlx5e_rq *rq, struct xdp_b
>>   	skb_put_data(skb, xdp->data_meta, totallen);
>>     	if (metalen) {
>> -		skb_metadata_set(skb, metalen);
>>   		__skb_pull(skb, metalen);
>> +		skb_metadata_set(skb, metalen);
>>   	}
>>     	return skb;
>> 
>
> Patch itself is simple..
>
> I share my concerns about the perf impact of the series idea.
> Do you have some working PoC? Please share some perf numbers..

Sorry, nothing to show yet. I've shared more context in my reply to
Jakub [1].

The series itself is an interface cleanup, whether we end up needing it
for the metadata effort or not. Hence I wanted to salvage it from [2].

[1] https://lore.kernel.org/all/87bjixwv41.fsf@cloudflare.com/
[2] https://lore.kernel.org/r/20260107-skb-meta-safeproof-netdevs-rx-only-v3-0-0d461c5e4764@cloudflare.com