From 11a3a1546d0adc36485c2ad4af7ab950712df6ff Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 26 May 2008 17:48:13 +1000 Subject: [PATCH] virtio: fix delayed xmit of packet and freeing of old packets. Because we cache the last failed-to-xmit packet, if there are no packets queued behind that one we may never send it (reproduced here as TCP stalls, "cured" by an outgoing ping). Cc: Mark McLoughlin Signed-off-by: Rusty Russell Signed-off-by: Jeff Garzik --- drivers/net/virtio_net.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index d50f4fe352..5450eac9e2 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -47,6 +47,9 @@ struct virtnet_info /* Number of input buffers, and max we've ever had. */ unsigned int num, max; + /* For cleaning up after transmission. */ + struct tasklet_struct tasklet; + /* Receive & send queues. */ struct sk_buff_head recv; struct sk_buff_head send; @@ -68,8 +71,13 @@ static void skb_xmit_done(struct virtqueue *svq) /* Suppress further interrupts. */ svq->vq_ops->disable_cb(svq); + /* We were waiting for more output buffers. */ netif_wake_queue(vi->dev); + + /* Make sure we re-xmit last_xmit_skb: if there are no more packets + * queued, start_xmit won't be called. */ + tasklet_schedule(&vi->tasklet); } static void receive_skb(struct net_device *dev, struct sk_buff *skb, @@ -278,6 +286,18 @@ static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb) return vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb); } +static void xmit_tasklet(unsigned long data) +{ + struct virtnet_info *vi = (void *)data; + + netif_tx_lock_bh(vi->dev); + if (vi->last_xmit_skb && xmit_skb(vi, vi->last_xmit_skb) == 0) { + vi->svq->vq_ops->kick(vi->svq); + vi->last_xmit_skb = NULL; + } + netif_tx_unlock_bh(vi->dev); +} + static int start_xmit(struct sk_buff *skb, struct net_device *dev) { struct virtnet_info *vi = netdev_priv(dev); @@ -432,6 +452,8 @@ static int virtnet_probe(struct virtio_device *vdev) skb_queue_head_init(&vi->recv); skb_queue_head_init(&vi->send); + tasklet_init(&vi->tasklet, xmit_tasklet, (unsigned long)vi); + err = register_netdev(dev); if (err) { pr_debug("virtio_net: registering device failed\n"); -- 2.39.5