On 08/30/2018 10:09 AM, Björn Töpel wrote:
> From: Björn Töpel <bjorn.to...@intel.com>
>
> Previously, the AF_XDP (XDP_DRV/XDP_SKB copy-mode) ingress logic did
> not include XDP meta data in the data buffers copied out to the user
> application.
>
> In this commit, we check if meta data is available, and if so, it is
> prepended to the frame.
>
> Signed-off-by: Björn Töpel <bjorn.to...@intel.com>
> ---
> net/xdp/xsk.c | 37 ++++++++++++++++++++++++++++---------
> 1 file changed, 28 insertions(+), 9 deletions(-)
>
> diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
> index 4e937cd7c17d..817e4cee1540 100644
> --- a/net/xdp/xsk.c
> +++ b/net/xdp/xsk.c
> @@ -55,20 +55,30 @@ EXPORT_SYMBOL(xsk_umem_discard_addr);
>
> static int __xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
> {
> - void *buffer;
> + void *to_buf, *from_buf;
> + u32 metalen;
> u64 addr;
> int err;
>
> if (!xskq_peek_addr(xs->umem->fq, &addr) ||
> - len > xs->umem->chunk_size_nohr) {
> + len > xs->umem->chunk_size_nohr - XDP_PACKET_HEADROOM) {
> xs->rx_dropped++;
> return -ENOSPC;
> }
>
> addr += xs->umem->headroom;
>
> - buffer = xdp_umem_get_data(xs->umem, addr);
> - memcpy(buffer, xdp->data, len);
> + if (xdp_data_meta_unsupported(xdp)) {
Nit: Probably makes sense to wrap with unlikely() since we expect all
drivers to implement this.
> + from_buf = xdp->data;
> + metalen = 0;
> + } else {
> + from_buf = xdp->data_meta;
> + metalen = xdp->data - xdp->data_meta;
> + }
> +
> + to_buf = xdp_umem_get_data(xs->umem, addr);
> + memcpy(to_buf, from_buf, len + metalen);
> + addr += metalen;
> err = xskq_produce_batch_desc(xs->rx, addr, len);
> if (!err) {
> xskq_discard_addr(xs->umem->fq);
> @@ -111,8 +121,8 @@ void xsk_flush(struct xdp_sock *xs)
>
> int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
> {
> - u32 len = xdp->data_end - xdp->data;
> - void *buffer;
> + u32 metalen, len = xdp->data_end - xdp->data;
> + void *to_buf, *from_buf;
> u64 addr;
> int err;
>
> @@ -120,15 +130,24 @@ int xsk_generic_rcv(struct xdp_sock *xs, struct
> xdp_buff *xdp)
> return -EINVAL;
>
> if (!xskq_peek_addr(xs->umem->fq, &addr) ||
> - len > xs->umem->chunk_size_nohr) {
> + len > xs->umem->chunk_size_nohr - XDP_PACKET_HEADROOM) {
> xs->rx_dropped++;
> return -ENOSPC;
> }
>
> addr += xs->umem->headroom;
>
> - buffer = xdp_umem_get_data(xs->umem, addr);
> - memcpy(buffer, xdp->data, len);
> + if (xdp_data_meta_unsupported(xdp)) {
> + from_buf = xdp->data;
> + metalen = 0;
Note that this condition should be dead code. netif_receive_generic_xdp()
sets xdp->data_meta to xdp->data, so all good here and above is never hit.
> + } else {
> + from_buf = xdp->data_meta;
> + metalen = xdp->data - xdp->data_meta;
> + }
> +
> + to_buf = xdp_umem_get_data(xs->umem, addr);
> + memcpy(to_buf, from_buf, len + metalen);
> + addr += metalen;
> err = xskq_produce_batch_desc(xs->rx, addr, len);
> if (!err) {
> xskq_discard_addr(xs->umem->fq);
>
