Re: [PATCH bpf-next v4 2/6] net: tun: enable transfer of XDP metadata to skb

[Martin KaFai Lau]

On 2/27/25 6:23 AM, Marcus Wichelmann wrote:
> When the XDP metadata area was used, it is expected that the same
> metadata can also be accessed from TC, as can be read in the description
> of the bpf_xdp_adjust_meta helper function. In the tun driver, this was
> not yet implemented.
>
> To make this work, the skb that is being built on XDP_PASS should know
> of the current size of the metadata area. This is ensured by adding
> calls to skb_metadata_set. For the tun_xdp_one code path, an additional
> check is necessary to handle the case where the externally initialized
> xdp_buff has no metadata support (xdp->data_meta == xdp->data + 1).
>
> More information about this feature can be found in the commit message
> of commit de8f3a83b0a0 ("bpf: add meta pointer for direct access").
> > Signed-off-by: Marcus Wichelmann <marcus.wichelmann@xxxxxxxxxxxxxxxx>
> Reviewed-by: Willem de Bruijn <willemb@xxxxxxxxxx>
> Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
> ---
>   drivers/net/tun.c | 25 ++++++++++++++++++++++---
>   1 file changed, 22 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> index 4ec8fbd93c8d..70208b3a2e93 100644
> --- a/drivers/net/tun.c
> +++ b/drivers/net/tun.c

The changes have conflicts with the commit 2506251e81d1 ("tun: Decouple vnet handling").

It is better to rebase the works onto the bpf-next/net,
i.e. the "net" branch instead of the "master" branch.