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Commit cac320c8 authored by Jesper Dangaard Brouer's avatar Jesper Dangaard Brouer Committed by David S. Miller
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virtio_net: convert to use generic xdp_frame and xdp_return_frame API 



The virtio_net driver assumes XDP frames are always released based on
page refcnt (via put_page).  Thus, is only queues the XDP data pointer
address and uses virt_to_head_page() to retrieve struct page.

Use the XDP return API to get away from such assumptions. Instead
queue an xdp_frame, which allow us to use the xdp_return_frame API,
when releasing the frame.

V8: Avoid endianness issues (found by kbuild test robot)
V9: Change __virtnet_xdp_xmit from bool to int return value (found by Dan Carpenter)

Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1ffcbc85

drivers/net/virtio_net.c

+29 −25
Original line number Diff line number Diff line
@@ -415,38 +415,48 @@ static void virtnet_xdp_flush(struct net_device *dev) 
	virtqueue_kick(sq->vq);

}



static bool __virtnet_xdp_xmit(struct virtnet_info *vi,

static int __virtnet_xdp_xmit(struct virtnet_info *vi,

			      struct xdp_buff *xdp)

{

	struct virtio_net_hdr_mrg_rxbuf *hdr;

	unsigned int len;

	struct xdp_frame *xdpf, *xdpf_sent;

	struct send_queue *sq;

	unsigned int len;

	unsigned int qp;

	void *xdp_sent;

	int err;



	qp = vi->curr_queue_pairs - vi->xdp_queue_pairs + smp_processor_id();

	sq = &vi->sq[qp];



	/* Free up any pending old buffers before queueing new ones. */

	while ((xdp_sent = virtqueue_get_buf(sq->vq, &len)) != NULL) {

		struct page *sent_page = virt_to_head_page(xdp_sent);

	while ((xdpf_sent = virtqueue_get_buf(sq->vq, &len)) != NULL)

		xdp_return_frame(xdpf_sent->data, &xdpf_sent->mem);



		put_page(sent_page);

	}

	xdpf = convert_to_xdp_frame(xdp);

	if (unlikely(!xdpf))

		return -EOVERFLOW;



	/* virtqueue want to use data area in-front of packet */

	if (unlikely(xdpf->metasize > 0))

		return -EOPNOTSUPP;



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

		return -EOVERFLOW;



	xdp->data -= vi->hdr_len;

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

	xdpf->data -= vi->hdr_len;

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

	hdr = xdp->data;

	hdr = xdpf->data;

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

	xdpf->len   += vi->hdr_len;



	sg_init_one(sq->sg, xdp->data, xdp->data_end - xdp->data);

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



	err = virtqueue_add_outbuf(sq->vq, sq->sg, 1, xdp->data, GFP_ATOMIC);

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

	if (unlikely(err))

		return false; /* Caller handle free/refcnt */

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



	return true;

	return 0;

}



static int virtnet_xdp_xmit(struct net_device *dev, struct xdp_buff *xdp)
@@ -454,7 +464,6 @@ static int virtnet_xdp_xmit(struct net_device *dev, struct xdp_buff *xdp) 
	struct virtnet_info *vi = netdev_priv(dev);

	struct receive_queue *rq = vi->rq;

	struct bpf_prog *xdp_prog;

	bool sent;



	/* Only allow ndo_xdp_xmit if XDP is loaded on dev, as this

	 * indicate XDP resources have been successfully allocated.
@@ -463,10 +472,7 @@ static int virtnet_xdp_xmit(struct net_device *dev, struct xdp_buff *xdp) 
	if (!xdp_prog)

		return -ENXIO;



	sent = __virtnet_xdp_xmit(vi, xdp);

	if (!sent)

		return -ENOSPC;

	return 0;

	return __virtnet_xdp_xmit(vi, xdp);

}



static unsigned int virtnet_get_headroom(struct virtnet_info *vi)
@@ -555,7 +561,6 @@ static struct sk_buff *receive_small(struct net_device *dev, 
	struct page *page = virt_to_head_page(buf);

	unsigned int delta = 0;

	struct page *xdp_page;

	bool sent;

	int err;



	len -= vi->hdr_len;
@@ -606,8 +611,8 @@ static struct sk_buff *receive_small(struct net_device *dev, 
			delta = orig_data - xdp.data;

			break;

		case XDP_TX:

			sent = __virtnet_xdp_xmit(vi, &xdp);

			if (unlikely(!sent)) {

			err = __virtnet_xdp_xmit(vi, &xdp);

			if (unlikely(err)) {

				trace_xdp_exception(vi->dev, xdp_prog, act);

				goto err_xdp;

			}
@@ -690,7 +695,6 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, 
	struct bpf_prog *xdp_prog;

	unsigned int truesize;

	unsigned int headroom = mergeable_ctx_to_headroom(ctx);

	bool sent;

	int err;



	head_skb = NULL;
@@ -762,8 +766,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, 
			}

			break;

		case XDP_TX:

			sent = __virtnet_xdp_xmit(vi, &xdp);

			if (unlikely(!sent)) {

			err = __virtnet_xdp_xmit(vi, &xdp);

			if (unlikely(err)) {

				trace_xdp_exception(vi->dev, xdp_prog, act);

				if (unlikely(xdp_page != page))

					put_page(xdp_page);