Stanislav Fomichev <sdf@xxxxxxxxxx> writes:
> No functional changes. Boilerplate to allow stuffing more data after xdp_buff.
>
> Cc: Tariq Toukan <tariqt@xxxxxxxxxx>
> Cc: John Fastabend <john.fastabend@xxxxxxxxx>
> Cc: David Ahern <dsahern@xxxxxxxxx>
> Cc: Martin KaFai Lau <martin.lau@xxxxxxxxx>
> Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
> Cc: Willem de Bruijn <willemb@xxxxxxxxxx>
> Cc: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
> Cc: Anatoly Burakov <anatoly.burakov@xxxxxxxxx>
> Cc: Alexander Lobakin <alexandr.lobakin@xxxxxxxxx>
> Cc: Magnus Karlsson <magnus.karlsson@xxxxxxxxx>
> Cc: Maryam Tahhan <mtahhan@xxxxxxxxxx>
> Cc: xdp-hints@xxxxxxxxxxxxxxx
> Cc: netdev@xxxxxxxxxxxxxxx
> Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
> ---
> drivers/net/ethernet/mellanox/mlx4/en_rx.c | 26 +++++++++++++---------
> 1 file changed, 15 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> index 8f762fc170b3..467356633172 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
> @@ -661,17 +661,21 @@ static int check_csum(struct mlx4_cqe *cqe, struct sk_buff *skb, void *va,
> #define MLX4_CQE_STATUS_IP_ANY (MLX4_CQE_STATUS_IPV4)
> #endif
>
> +struct mlx4_xdp_buff {
> + struct xdp_buff xdp;
> +};
This embedding trick works for drivers that put xdp_buff on the stack,
but mlx5 supports XSK zerocopy, which uses the xsk_buff_pool for
allocating them. This makes it a bit awkward to do the same thing there;
and since it's probably going to be fairly common to do something like
this, how about we just add a 'void *drv_priv' pointer to struct
xdp_buff that the drivers can use? The xdp_buff already takes up a full
cache line anyway, so any data stuffed after it will spill over to a new
one; so I don't think there's much difference performance-wise.
I'll send my patch to add support to mlx5 (using the drv_priv pointer
approach) separately.
-Toke
