On Mon, 27 Nov 2023 11:03:07 -0800 Stanislav Fomichev wrote: > For zerocopy mode, tx_desc->addr can point to an arbitrary offset > and carry some TX metadata in the headroom. For copy mode, there > is no way currently to populate skb metadata. > > Introduce new tx_metadata_len umem config option that indicates how many > bytes to treat as metadata. Metadata bytes come prior to tx_desc address > (same as in RX case). > > The size of the metadata has mostly the same constraints as XDP: > - less than 256 bytes > - 8-byte aligned (compared to 4-byte alignment on xdp, due to 8-byte > timestamp in the completion) > - non-zero > > This data is not interpreted in any way right now. Reviewed-by: Jakub Kicinski <kuba@xxxxxxxxxx>
