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

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This fixes a potential dangling xmit problem.

We also suppress refill interrupts until we need them.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell 2008-02-04 23:50:07 -05:00
parent a48bd8f670
commit 2cb9c6bafc
1 changed files with 19 additions and 6 deletions
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25
drivers/net/virtio_net.c
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@ -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)); 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); 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)); pr_debug("%s: xmit %p %s\n", dev->name, skb, print_mac(mac, dest));
free_old_xmit_skbs(vi);
/* Encode metadata header at front. */ /* Encode metadata header at front. */
hdr = skb_vnet_hdr(skb); hdr = skb_vnet_hdr(skb);
if (skb->ip_summed == CHECKSUM_PARTIAL) { 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); vnet_hdr_to_sg(sg, skb);
num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1; num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
__skb_queue_head(&vi->send, skb); __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); err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
if (err) { if (err) {
pr_debug("%s: virtio not prepared to send\n", dev->name); pr_debug("%s: virtio not prepared to send\n", dev->name);
skb_unlink(skb, &vi->send);
netif_stop_queue(dev); 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; return NETDEV_TX_BUSY;
} }
vi->svq->vq_ops->kick(vi->svq); vi->svq->vq_ops->kick(vi->svq);