Messages in this thread |  | | Subject | Re: [PATCH net] veth: xdp: use head instead of hard_start | From | Toshiaki Makita <> | Date | Tue, 31 Mar 2020 08:35:39 +0900 |
| |
Hi Mao & Jesper (Resending with plain text...)
On 2020/03/30 20:34, Jesper Dangaard Brouer wrote: > On Mon, 30 Mar 2020 18:26:31 +0800 > Mao Wenan <maowenan@huawei.com> wrote: > >> xdp.data_hard_start is mapped to the first >> address of xdp_frame, but the pointer hard_start >> is the offset(sizeof(struct xdp_frame)) of xdp_frame, >> it should use head instead of hard_start to >> set xdp.data_hard_start. Otherwise, if BPF program >> calls helper_function such as bpf_xdp_adjust_head, it >> will be confused for xdp_frame_end. > > I have noticed this[1] and have a patch in my current patchset for > fixing this. IMHO is is not so important fix right now, as the effect > is that you currently only lose 32 bytes of headroom. > > [1] https://lore.kernel.org/netdev/158446621887.702578.17234304084556809684.stgit@firesoul/
You are right, the subtraction is not necessary here. Thank you for working on this.
Toshiaki Makita
|  |