> On Tue, 03 Jan 2023 16:19:49 +0100 Toke Høiland-Jørgensen wrote:
> > Hmm, good question! I don't think we've ever explicitly documented any
> > assumptions one way or the other. My own mental model has certainly
> > always assumed the first frag would continue to be the same size as in
> > non-multi-buf packets.
> 
> Interesting! :) My mental model was closer to GRO by frags 
> so the linear part would have no data, just headers.

That is assumption as well.

Regards,
Lorenzo

> 
> A random datapoint is that bpf_xdp_adjust_head() seems 
> to enforce that there is at least ETH_HLEN.