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Commit 2471c75e authored by Jesper Dangaard Brouer's avatar Jesper Dangaard Brouer Committed by David S. Miller
Browse files

virtio_net: split XDP_TX kick and XDP_REDIRECT map flushing 



The driver was combining XDP_TX virtqueue_kick and XDP_REDIRECT
map flushing (xdp_do_flush_map).  This is suboptimal, these two
flush operations should be kept separate.

The suboptimal behavior was introduced in commit 9267c430
("virtio-net: add missing virtqueue kick when flushing packets").

Fixes: 9267c430 ("virtio-net: add missing virtqueue kick when flushing packets")
Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2e689312

drivers/net/virtio_net.c

+19 −11
Original line number Diff line number Diff line
@@ -53,6 +53,10 @@ module_param(napi_tx, bool, 0644); 
/* Amount of XDP headroom to prepend to packets for use by xdp_adjust_head */

#define VIRTIO_XDP_HEADROOM 256



/* Separating two types of XDP xmit */

#define VIRTIO_XDP_TX		BIT(0)

#define VIRTIO_XDP_REDIR	BIT(1)



/* RX packet size EWMA. The average packet size is used to determine the packet

 * buffer size when refilling RX rings. As the entire RX ring may be refilled

 * at once, the weight is chosen so that the EWMA will be insensitive to short-
@@ -582,7 +586,7 @@ static struct sk_buff *receive_small(struct net_device *dev, 
				     struct receive_queue *rq,

				     void *buf, void *ctx,

				     unsigned int len,

				     bool *xdp_xmit)

				     unsigned int *xdp_xmit)

{

	struct sk_buff *skb;

	struct bpf_prog *xdp_prog;
@@ -654,14 +658,14 @@ static struct sk_buff *receive_small(struct net_device *dev, 
				trace_xdp_exception(vi->dev, xdp_prog, act);

				goto err_xdp;

			}

			*xdp_xmit = true;

			*xdp_xmit |= VIRTIO_XDP_TX;

			rcu_read_unlock();

			goto xdp_xmit;

		case XDP_REDIRECT:

			err = xdp_do_redirect(dev, &xdp, xdp_prog);

			if (err)

				goto err_xdp;

			*xdp_xmit = true;

			*xdp_xmit |= VIRTIO_XDP_REDIR;

			rcu_read_unlock();

			goto xdp_xmit;

		default:
@@ -723,7 +727,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, 
					 void *buf,

					 void *ctx,

					 unsigned int len,

					 bool *xdp_xmit)

					 unsigned int *xdp_xmit)

{

	struct virtio_net_hdr_mrg_rxbuf *hdr = buf;

	u16 num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
@@ -818,7 +822,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, 
					put_page(xdp_page);

				goto err_xdp;

			}

			*xdp_xmit = true;

			*xdp_xmit |= VIRTIO_XDP_TX;

			if (unlikely(xdp_page != page))

				put_page(page);

			rcu_read_unlock();
@@ -830,7 +834,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, 
					put_page(xdp_page);

				goto err_xdp;

			}

			*xdp_xmit = true;

			*xdp_xmit |= VIRTIO_XDP_REDIR;

			if (unlikely(xdp_page != page))

				put_page(page);

			rcu_read_unlock();
@@ -939,7 +943,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, 
}



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

		       void *buf, unsigned int len, void **ctx, bool *xdp_xmit)

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

		       unsigned int *xdp_xmit)

{

	struct net_device *dev = vi->dev;

	struct sk_buff *skb;
@@ -1232,7 +1237,8 @@ static void refill_work(struct work_struct *work) 
	}

}



static int virtnet_receive(struct receive_queue *rq, int budget, bool *xdp_xmit)

static int virtnet_receive(struct receive_queue *rq, int budget,

			   unsigned int *xdp_xmit)

{

	struct virtnet_info *vi = rq->vq->vdev->priv;

	unsigned int len, received = 0, bytes = 0;
@@ -1321,7 +1327,7 @@ static int virtnet_poll(struct napi_struct *napi, int budget) 
	struct virtnet_info *vi = rq->vq->vdev->priv;

	struct send_queue *sq;

	unsigned int received, qp;

	bool xdp_xmit = false;

	unsigned int xdp_xmit = 0;



	virtnet_poll_cleantx(rq);
@@ -1331,12 +1337,14 @@ static int virtnet_poll(struct napi_struct *napi, int budget) 
	if (received < budget)

		virtqueue_napi_complete(napi, rq->vq, received);



	if (xdp_xmit) {

	if (xdp_xmit & VIRTIO_XDP_REDIR)

		xdp_do_flush_map();



	if (xdp_xmit & VIRTIO_XDP_TX) {

		qp = vi->curr_queue_pairs - vi->xdp_queue_pairs +

		     smp_processor_id();

		sq = &vi->sq[qp];

		virtqueue_kick(sq->vq);

		xdp_do_flush_map();

	}



	return received;