From 2cb9c6bafc58cf4066cb15f0ac6989a1015a02cc Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 4 Feb 2008 23:50:07 -0500 Subject: [PATCH] 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: Rusty Russell --- drivers/net/virtio_net.c | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index bd4d26a36e..a61c176607 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -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); -- 2.39.5