Commit 2cb9c6ba authored by Rusty Russell's avatar Rusty Russell
Browse files

virtio: free transmit skbs when notified, not on next xmit. 



This fixes a potential dangling xmit problem.

We also suppress refill interrupts until we need them.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent a48bd8f6

drivers/net/virtio_net.c

+19 −6
Original line number Diff line number Diff line
@@ -56,11 +56,13 @@ static inline void vnet_hdr_to_sg(struct scatterlist *sg, struct sk_buff *skb) 
	sg_init_one(sg, skb_vnet_hdr(skb), sizeof(struct virtio_net_hdr));

}



static void skb_xmit_done(struct virtqueue *rvq)

static void skb_xmit_done(struct virtqueue *svq)

{

	struct virtnet_info *vi = rvq->vdev->priv;

	struct virtnet_info *vi = svq->vdev->priv;



	/* In case we were waiting for output buffers. */

	/* Suppress further interrupts. */

	svq->vq_ops->disable_cb(svq);

	/* We were waiting for more output buffers. */

	netif_wake_queue(vi->dev);

}
@@ -232,8 +234,6 @@ static int start_xmit(struct sk_buff *skb, struct net_device *dev) 


	pr_debug("%s: xmit %p %s\n", dev->name, skb, print_mac(mac, dest));



	free_old_xmit_skbs(vi);



	/* Encode metadata header at front. */

	hdr = skb_vnet_hdr(skb);

	if (skb->ip_summed == CHECKSUM_PARTIAL) {
@@ -266,11 +266,24 @@ static int start_xmit(struct sk_buff *skb, struct net_device *dev) 
	vnet_hdr_to_sg(sg, skb);

	num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;

	__skb_queue_head(&vi->send, skb);



again:

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

	free_old_xmit_skbs(vi);

	err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);

	if (err) {

		pr_debug("%s: virtio not prepared to send\n", dev->name);

		skb_unlink(skb, &vi->send);

		netif_stop_queue(dev);



		/* Activate callback for using skbs: if this fails it

		 * means some were used in the meantime. */

		if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {

			printk("Unlikely: restart svq failed\n");

			netif_start_queue(dev);

			goto again;

		}

		__skb_unlink(skb, &vi->send);



		return NETDEV_TX_BUSY;

	}

	vi->svq->vq_ops->kick(vi->svq);