Commit 97717e8d authored by Heng Qi's avatar Heng Qi Committed by David S. Miller
Browse files

virtio-net: transmit the multi-buffer xdp 



This serves as the basis for XDP_TX and XDP_REDIRECT
to send a multi-buffer xdp_frame.

Signed-off-by: default avatarHeng Qi <hengqi@linux.alibaba.com>
Reviewed-by: default avatarXuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 22174f79

drivers/net/virtio_net.c

+26 −5
Original line number Diff line number Diff line
@@ -570,22 +570,43 @@ static int __virtnet_xdp_xmit_one(struct virtnet_info *vi, 
				   struct xdp_frame *xdpf)

{

	struct virtio_net_hdr_mrg_rxbuf *hdr;

	int err;

	struct skb_shared_info *shinfo;

	u8 nr_frags = 0;

	int err, i;



	if (unlikely(xdpf->headroom < vi->hdr_len))

		return -EOVERFLOW;



	/* Make room for virtqueue hdr (also change xdpf->headroom?) */

	if (unlikely(xdp_frame_has_frags(xdpf))) {

		shinfo = xdp_get_shared_info_from_frame(xdpf);

		nr_frags = shinfo->nr_frags;

	}



	/* In wrapping function virtnet_xdp_xmit(), we need to free

	 * up the pending old buffers, where we need to calculate the

	 * position of skb_shared_info in xdp_get_frame_len() and

	 * xdp_return_frame(), which will involve to xdpf->data and

	 * xdpf->headroom. Therefore, we need to update the value of

	 * headroom synchronously here.

	 */

	xdpf->headroom -= vi->hdr_len;

	xdpf->data -= vi->hdr_len;

	/* Zero header and leave csum up to XDP layers */

	hdr = xdpf->data;

	memset(hdr, 0, vi->hdr_len);

	xdpf->len   += vi->hdr_len;



	sg_init_one(sq->sg, xdpf->data, xdpf->len);

	sg_init_table(sq->sg, nr_frags + 1);

	sg_set_buf(sq->sg, xdpf->data, xdpf->len);

	for (i = 0; i < nr_frags; i++) {

		skb_frag_t *frag = &shinfo->frags[i];



		sg_set_page(&sq->sg[i + 1], skb_frag_page(frag),

			    skb_frag_size(frag), skb_frag_off(frag));

	}



	err = virtqueue_add_outbuf(sq->vq, sq->sg, 1, xdp_to_ptr(xdpf),

				   GFP_ATOMIC);

	err = virtqueue_add_outbuf(sq->vq, sq->sg, nr_frags + 1,

				   xdp_to_ptr(xdpf), GFP_ATOMIC);

	if (unlikely(err))

		return -ENOSPC; /* Caller handle free/refcnt */