Commit ecbc42ca authored by Toshiaki Makita's avatar Toshiaki Makita Committed by David S. Miller
Browse files

virtio_net: Fix incosistent received bytes counter 



When received packets are dropped in virtio_net driver, received packets
counter is incremented but bytes counter is not.
As a result, for instance if we drop all packets by XDP, only received
is counted and bytes stays 0, which looks inconsistent.
IMHO received packets/bytes should be counted if packets are produced by
the hypervisor, like what common NICs on physical machines are doing.
So fix the bytes counter.

Signed-off-by: default avatarToshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9981b4fb

drivers/net/virtio_net.c

+23 −18
Original line number Diff line number Diff line
@@ -586,7 +586,8 @@ static struct sk_buff *receive_small(struct net_device *dev, 
				     struct receive_queue *rq,

				     void *buf, void *ctx,

				     unsigned int len,

				     unsigned int *xdp_xmit)

				     unsigned int *xdp_xmit,

				     unsigned int *rbytes)

{

	struct sk_buff *skb;

	struct bpf_prog *xdp_prog;
@@ -601,6 +602,7 @@ static struct sk_buff *receive_small(struct net_device *dev, 
	int err;



	len -= vi->hdr_len;

	*rbytes += len;



	rcu_read_lock();

	xdp_prog = rcu_dereference(rq->xdp_prog);
@@ -705,11 +707,13 @@ static struct sk_buff *receive_big(struct net_device *dev, 
				   struct virtnet_info *vi,

				   struct receive_queue *rq,

				   void *buf,

				   unsigned int len)

				   unsigned int len,

				   unsigned int *rbytes)

{

	struct page *page = buf;

	struct sk_buff *skb = page_to_skb(vi, rq, page, 0, len, PAGE_SIZE);



	*rbytes += len - vi->hdr_len;

	if (unlikely(!skb))

		goto err;
@@ -727,7 +731,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, 
					 void *buf,

					 void *ctx,

					 unsigned int len,

					 unsigned int *xdp_xmit)

					 unsigned int *xdp_xmit,

					 unsigned int *rbytes)

{

	struct virtio_net_hdr_mrg_rxbuf *hdr = buf;

	u16 num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
@@ -740,6 +745,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, 
	int err;



	head_skb = NULL;

	*rbytes += len - vi->hdr_len;



	rcu_read_lock();

	xdp_prog = rcu_dereference(rq->xdp_prog);
@@ -877,6 +883,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, 
			goto err_buf;

		}



		*rbytes += len;

		page = virt_to_head_page(buf);



		truesize = mergeable_ctx_to_truesize(ctx);
@@ -932,6 +939,7 @@ err_skb: 
			dev->stats.rx_length_errors++;

			break;

		}

		*rbytes += len;

		page = virt_to_head_page(buf);

		put_page(page);

	}
@@ -942,14 +950,13 @@ xdp_xmit: 
	return NULL;

}



static int receive_buf(struct virtnet_info *vi, struct receive_queue *rq,

static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,

			void *buf, unsigned int len, void **ctx,

		       unsigned int *xdp_xmit)

			unsigned int *xdp_xmit, unsigned int *rbytes)

{

	struct net_device *dev = vi->dev;

	struct sk_buff *skb;

	struct virtio_net_hdr_mrg_rxbuf *hdr;

	int ret;



	if (unlikely(len < vi->hdr_len + ETH_HLEN)) {

		pr_debug("%s: short packet %i\n", dev->name, len);
@@ -961,23 +968,22 @@ static int receive_buf(struct virtnet_info *vi, struct receive_queue *rq, 
		} else {

			put_page(virt_to_head_page(buf));

		}

		return 0;

		return;

	}



	if (vi->mergeable_rx_bufs)

		skb = receive_mergeable(dev, vi, rq, buf, ctx, len, xdp_xmit);

		skb = receive_mergeable(dev, vi, rq, buf, ctx, len, xdp_xmit,

					rbytes);

	else if (vi->big_packets)

		skb = receive_big(dev, vi, rq, buf, len);

		skb = receive_big(dev, vi, rq, buf, len, rbytes);

	else

		skb = receive_small(dev, vi, rq, buf, ctx, len, xdp_xmit);

		skb = receive_small(dev, vi, rq, buf, ctx, len, xdp_xmit, rbytes);



	if (unlikely(!skb))

		return 0;

		return;



	hdr = skb_vnet_hdr(skb);



	ret = skb->len;



	if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID)

		skb->ip_summed = CHECKSUM_UNNECESSARY;
@@ -994,12 +1000,11 @@ static int receive_buf(struct virtnet_info *vi, struct receive_queue *rq, 
		 ntohs(skb->protocol), skb->len, skb->pkt_type);



	napi_gro_receive(&rq->napi, skb);

	return ret;

	return;



frame_err:

	dev->stats.rx_frame_errors++;

	dev_kfree_skb(skb);

	return 0;

}



/* Unlike mergeable buffers, all buffers are allocated to the
@@ -1249,13 +1254,13 @@ static int virtnet_receive(struct receive_queue *rq, int budget, 


		while (received < budget &&

		       (buf = virtqueue_get_buf_ctx(rq->vq, &len, &ctx))) {

			bytes += receive_buf(vi, rq, buf, len, ctx, xdp_xmit);

			receive_buf(vi, rq, buf, len, ctx, xdp_xmit, &bytes);

			received++;

		}

	} else {

		while (received < budget &&

		       (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {

			bytes += receive_buf(vi, rq, buf, len, NULL, xdp_xmit);

			receive_buf(vi, rq, buf, len, NULL, xdp_xmit, &bytes);

			received++;

		}

	}

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