X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=drivers%2Fnet%2Fvirtio_net.c;h=b0a85d0387962b6ce2394637f9ae6dbbac5f6684;hb=f8965467f366fd18f01feafb5db10512d7b4422c;hp=52198f6797a48a88a76bfee8cc4f6cfe64925ea8;hpb=9cbc1cb8cd46ce1f7645b9de249b2ce8460129bb;p=safe%2Fjmp%2Flinux-2.6

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 52198f6..b0a85d0 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1,4 +1,4 @@
-/* A simple network driver using virtio.
+/* A network driver using virtio.
  *
  * Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
  *
@@ -25,6 +25,7 @@
 #include <linux/virtio_net.h>
 #include <linux/scatterlist.h>
 #include <linux/if_vlan.h>
+#include <linux/slab.h>
 
 static int napi_weight = 128;
 module_param(napi_weight, int, 0444);
@@ -39,69 +40,79 @@ module_param(gso, bool, 0444);
 
 #define VIRTNET_SEND_COMMAND_SG_MAX    2
 
-struct virtnet_info
-{
+struct virtnet_info {
 	struct virtio_device *vdev;
 	struct virtqueue *rvq, *svq, *cvq;
 	struct net_device *dev;
 	struct napi_struct napi;
 	unsigned int status;
 
-	/* The skb we couldn't send because buffers were full. */
-	struct sk_buff *last_xmit_skb;
-
-	/* If we need to free in a timer, this is it. */
-	struct timer_list xmit_free_timer;
-
 	/* Number of input buffers, and max we've ever had. */
 	unsigned int num, max;
 
-	/* For cleaning up after transmission. */
-	struct tasklet_struct tasklet;
-	bool free_in_tasklet;
-
 	/* I like... big packets and I cannot lie! */
 	bool big_packets;
 
 	/* Host will merge rx buffers for big packets (shake it! shake it!) */
 	bool mergeable_rx_bufs;
 
-	/* Receive & send queues. */
-	struct sk_buff_head recv;
-	struct sk_buff_head send;
+	/* Work struct for refilling if we run low on memory. */
+	struct delayed_work refill;
 
 	/* Chain pages by the private ptr. */
 	struct page *pages;
+
+	/* fragments + linear part + virtio header */
+	struct scatterlist rx_sg[MAX_SKB_FRAGS + 2];
+	struct scatterlist tx_sg[MAX_SKB_FRAGS + 2];
 };
 
-static inline void *skb_vnet_hdr(struct sk_buff *skb)
-{
-	return (struct virtio_net_hdr *)skb->cb;
-}
+struct skb_vnet_hdr {
+	union {
+		struct virtio_net_hdr hdr;
+		struct virtio_net_hdr_mrg_rxbuf mhdr;
+	};
+	unsigned int num_sg;
+};
+
+struct padded_vnet_hdr {
+	struct virtio_net_hdr hdr;
+	/*
+	 * virtio_net_hdr should be in a separated sg buffer because of a
+	 * QEMU bug, and data sg buffer shares same page with this header sg.
+	 * This padding makes next sg 16 byte aligned after virtio_net_hdr.
+	 */
+	char padding[6];
+};
 
-static void give_a_page(struct virtnet_info *vi, struct page *page)
+static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
 {
-	page->private = (unsigned long)vi->pages;
-	vi->pages = page;
+	return (struct skb_vnet_hdr *)skb->cb;
 }
 
-static void trim_pages(struct virtnet_info *vi, struct sk_buff *skb)
+/*
+ * private is used to chain pages for big packets, put the whole
+ * most recent used list in the beginning for reuse
+ */
+static void give_pages(struct virtnet_info *vi, struct page *page)
 {
-	unsigned int i;
+	struct page *end;
 
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
-		give_a_page(vi, skb_shinfo(skb)->frags[i].page);
-	skb_shinfo(skb)->nr_frags = 0;
-	skb->data_len = 0;
+	/* Find end of list, sew whole thing into vi->pages. */
+	for (end = page; end->private; end = (struct page *)end->private);
+	end->private = (unsigned long)vi->pages;
+	vi->pages = page;
 }
 
 static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask)
 {
 	struct page *p = vi->pages;
 
-	if (p)
+	if (p) {
 		vi->pages = (struct page *)p->private;
-	else
+		/* clear private here, it is used to chain pages */
+		p->private = 0;
+	} else
 		p = alloc_page(gfp_mask);
 	return p;
 }
@@ -115,113 +126,153 @@ static void skb_xmit_done(struct virtqueue *svq)
 
 	/* We were probably 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 set_skb_frag(struct sk_buff *skb, struct page *page,
+			 unsigned int offset, unsigned int *len)
+{
+	int i = skb_shinfo(skb)->nr_frags;
+	skb_frag_t *f;
+
+	f = &skb_shinfo(skb)->frags[i];
+	f->size = min((unsigned)PAGE_SIZE - offset, *len);
+	f->page_offset = offset;
+	f->page = page;
+
+	skb->data_len += f->size;
+	skb->len += f->size;
+	skb_shinfo(skb)->nr_frags++;
+	*len -= f->size;
 }
 
-static void receive_skb(struct net_device *dev, struct sk_buff *skb,
-			unsigned len)
+static struct sk_buff *page_to_skb(struct virtnet_info *vi,
+				   struct page *page, unsigned int len)
 {
-	struct virtnet_info *vi = netdev_priv(dev);
-	struct virtio_net_hdr *hdr = skb_vnet_hdr(skb);
-	int err;
-	int i;
+	struct sk_buff *skb;
+	struct skb_vnet_hdr *hdr;
+	unsigned int copy, hdr_len, offset;
+	char *p;
 
-	if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
-		pr_debug("%s: short packet %i\n", dev->name, len);
-		dev->stats.rx_length_errors++;
-		goto drop;
-	}
+	p = page_address(page);
 
-	if (vi->mergeable_rx_bufs) {
-		struct virtio_net_hdr_mrg_rxbuf *mhdr = skb_vnet_hdr(skb);
-		unsigned int copy;
-		char *p = page_address(skb_shinfo(skb)->frags[0].page);
+	/* copy small packet so we can reuse these pages for small data */
+	skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
+	if (unlikely(!skb))
+		return NULL;
 
-		if (len > PAGE_SIZE)
-			len = PAGE_SIZE;
-		len -= sizeof(struct virtio_net_hdr_mrg_rxbuf);
+	hdr = skb_vnet_hdr(skb);
 
-		memcpy(hdr, p, sizeof(*mhdr));
-		p += sizeof(*mhdr);
+	if (vi->mergeable_rx_bufs) {
+		hdr_len = sizeof hdr->mhdr;
+		offset = hdr_len;
+	} else {
+		hdr_len = sizeof hdr->hdr;
+		offset = sizeof(struct padded_vnet_hdr);
+	}
 
-		copy = len;
-		if (copy > skb_tailroom(skb))
-			copy = skb_tailroom(skb);
+	memcpy(hdr, p, hdr_len);
 
-		memcpy(skb_put(skb, copy), p, copy);
+	len -= hdr_len;
+	p += offset;
 
-		len -= copy;
+	copy = len;
+	if (copy > skb_tailroom(skb))
+		copy = skb_tailroom(skb);
+	memcpy(skb_put(skb, copy), p, copy);
 
-		if (!len) {
-			give_a_page(vi, skb_shinfo(skb)->frags[0].page);
-			skb_shinfo(skb)->nr_frags--;
-		} else {
-			skb_shinfo(skb)->frags[0].page_offset +=
-				sizeof(*mhdr) + copy;
-			skb_shinfo(skb)->frags[0].size = len;
-			skb->data_len += len;
-			skb->len += len;
-		}
+	len -= copy;
+	offset += copy;
 
-		while (--mhdr->num_buffers) {
-			struct sk_buff *nskb;
+	while (len) {
+		set_skb_frag(skb, page, offset, &len);
+		page = (struct page *)page->private;
+		offset = 0;
+	}
 
-			i = skb_shinfo(skb)->nr_frags;
-			if (i >= MAX_SKB_FRAGS) {
-				pr_debug("%s: packet too long %d\n", dev->name,
-					 len);
-				dev->stats.rx_length_errors++;
-				goto drop;
-			}
+	if (page)
+		give_pages(vi, page);
 
-			nskb = vi->rvq->vq_ops->get_buf(vi->rvq, &len);
-			if (!nskb) {
-				pr_debug("%s: rx error: %d buffers missing\n",
-					 dev->name, mhdr->num_buffers);
-				dev->stats.rx_length_errors++;
-				goto drop;
-			}
+	return skb;
+}
 
-			__skb_unlink(nskb, &vi->recv);
-			vi->num--;
+static int receive_mergeable(struct virtnet_info *vi, struct sk_buff *skb)
+{
+	struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
+	struct page *page;
+	int num_buf, i, len;
+
+	num_buf = hdr->mhdr.num_buffers;
+	while (--num_buf) {
+		i = skb_shinfo(skb)->nr_frags;
+		if (i >= MAX_SKB_FRAGS) {
+			pr_debug("%s: packet too long\n", skb->dev->name);
+			skb->dev->stats.rx_length_errors++;
+			return -EINVAL;
+		}
 
-			skb_shinfo(skb)->frags[i] = skb_shinfo(nskb)->frags[0];
-			skb_shinfo(nskb)->nr_frags = 0;
-			kfree_skb(nskb);
+		page = vi->rvq->vq_ops->get_buf(vi->rvq, &len);
+		if (!page) {
+			pr_debug("%s: rx error: %d buffers missing\n",
+				 skb->dev->name, hdr->mhdr.num_buffers);
+			skb->dev->stats.rx_length_errors++;
+			return -EINVAL;
+		}
+		if (len > PAGE_SIZE)
+			len = PAGE_SIZE;
 
-			if (len > PAGE_SIZE)
-				len = PAGE_SIZE;
+		set_skb_frag(skb, page, 0, &len);
 
-			skb_shinfo(skb)->frags[i].size = len;
-			skb_shinfo(skb)->nr_frags++;
-			skb->data_len += len;
-			skb->len += len;
-		}
-	} else {
-		len -= sizeof(struct virtio_net_hdr);
+		--vi->num;
+	}
+	return 0;
+}
 
-		if (len <= MAX_PACKET_LEN)
-			trim_pages(vi, skb);
+static void receive_buf(struct net_device *dev, void *buf, unsigned int len)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	struct sk_buff *skb;
+	struct page *page;
+	struct skb_vnet_hdr *hdr;
 
-		err = pskb_trim(skb, len);
-		if (err) {
-			pr_debug("%s: pskb_trim failed %i %d\n", dev->name,
-				 len, err);
+	if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
+		pr_debug("%s: short packet %i\n", dev->name, len);
+		dev->stats.rx_length_errors++;
+		if (vi->mergeable_rx_bufs || vi->big_packets)
+			give_pages(vi, buf);
+		else
+			dev_kfree_skb(buf);
+		return;
+	}
+
+	if (!vi->mergeable_rx_bufs && !vi->big_packets) {
+		skb = buf;
+		len -= sizeof(struct virtio_net_hdr);
+		skb_trim(skb, len);
+	} else {
+		page = buf;
+		skb = page_to_skb(vi, page, len);
+		if (unlikely(!skb)) {
 			dev->stats.rx_dropped++;
-			goto drop;
+			give_pages(vi, page);
+			return;
 		}
+		if (vi->mergeable_rx_bufs)
+			if (receive_mergeable(vi, skb)) {
+				dev_kfree_skb(skb);
+				return;
+			}
 	}
 
+	hdr = skb_vnet_hdr(skb);
 	skb->truesize += skb->data_len;
 	dev->stats.rx_bytes += skb->len;
 	dev->stats.rx_packets++;
 
-	if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
+	if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 		pr_debug("Needs csum!\n");
-		if (!skb_partial_csum_set(skb,hdr->csum_start,hdr->csum_offset))
+		if (!skb_partial_csum_set(skb,
+					  hdr->hdr.csum_start,
+					  hdr->hdr.csum_offset))
 			goto frame_err;
 	}
 
@@ -229,9 +280,9 @@ static void receive_skb(struct net_device *dev, struct sk_buff *skb,
 	pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
 		 ntohs(skb->protocol), skb->len, skb->pkt_type);
 
-	if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
+	if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 		pr_debug("GSO!\n");
-		switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
+		switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 		case VIRTIO_NET_HDR_GSO_TCPV4:
 			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 			break;
@@ -244,14 +295,14 @@ static void receive_skb(struct net_device *dev, struct sk_buff *skb,
 		default:
 			if (net_ratelimit())
 				printk(KERN_WARNING "%s: bad gso type %u.\n",
-				       dev->name, hdr->gso_type);
+				       dev->name, hdr->hdr.gso_type);
 			goto frame_err;
 		}
 
-		if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
+		if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 			skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 
-		skb_shinfo(skb)->gso_size = hdr->gso_size;
+		skb_shinfo(skb)->gso_size = hdr->hdr.gso_size;
 		if (skb_shinfo(skb)->gso_size == 0) {
 			if (net_ratelimit())
 				printk(KERN_WARNING "%s: zero gso size.\n",
@@ -269,110 +320,121 @@ static void receive_skb(struct net_device *dev, struct sk_buff *skb,
 
 frame_err:
 	dev->stats.rx_frame_errors++;
-drop:
 	dev_kfree_skb(skb);
 }
 
-static void try_fill_recv_maxbufs(struct virtnet_info *vi)
+static int add_recvbuf_small(struct virtnet_info *vi, gfp_t gfp)
 {
 	struct sk_buff *skb;
-	struct scatterlist sg[2+MAX_SKB_FRAGS];
-	int num, err, i;
-
-	sg_init_table(sg, 2+MAX_SKB_FRAGS);
-	for (;;) {
-		struct virtio_net_hdr *hdr;
+	struct skb_vnet_hdr *hdr;
+	int err;
 
-		skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN + NET_IP_ALIGN);
-		if (unlikely(!skb))
-			break;
+	skb = netdev_alloc_skb_ip_align(vi->dev, MAX_PACKET_LEN);
+	if (unlikely(!skb))
+		return -ENOMEM;
 
-		skb_reserve(skb, NET_IP_ALIGN);
-		skb_put(skb, MAX_PACKET_LEN);
+	skb_put(skb, MAX_PACKET_LEN);
 
-		hdr = skb_vnet_hdr(skb);
-		sg_set_buf(sg, hdr, sizeof(*hdr));
+	hdr = skb_vnet_hdr(skb);
+	sg_set_buf(vi->rx_sg, &hdr->hdr, sizeof hdr->hdr);
 
-		if (vi->big_packets) {
-			for (i = 0; i < MAX_SKB_FRAGS; i++) {
-				skb_frag_t *f = &skb_shinfo(skb)->frags[i];
-				f->page = get_a_page(vi, GFP_ATOMIC);
-				if (!f->page)
-					break;
+	skb_to_sgvec(skb, vi->rx_sg + 1, 0, skb->len);
 
-				f->page_offset = 0;
-				f->size = PAGE_SIZE;
+	err = vi->rvq->vq_ops->add_buf(vi->rvq, vi->rx_sg, 0, 2, skb);
+	if (err < 0)
+		dev_kfree_skb(skb);
 
-				skb->data_len += PAGE_SIZE;
-				skb->len += PAGE_SIZE;
+	return err;
+}
 
-				skb_shinfo(skb)->nr_frags++;
-			}
+static int add_recvbuf_big(struct virtnet_info *vi, gfp_t gfp)
+{
+	struct page *first, *list = NULL;
+	char *p;
+	int i, err, offset;
+
+	/* page in vi->rx_sg[MAX_SKB_FRAGS + 1] is list tail */
+	for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
+		first = get_a_page(vi, gfp);
+		if (!first) {
+			if (list)
+				give_pages(vi, list);
+			return -ENOMEM;
 		}
+		sg_set_buf(&vi->rx_sg[i], page_address(first), PAGE_SIZE);
 
-		num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
-		skb_queue_head(&vi->recv, skb);
+		/* chain new page in list head to match sg */
+		first->private = (unsigned long)list;
+		list = first;
+	}
 
-		err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
-		if (err) {
-			skb_unlink(skb, &vi->recv);
-			trim_pages(vi, skb);
-			kfree_skb(skb);
-			break;
-		}
-		vi->num++;
+	first = get_a_page(vi, gfp);
+	if (!first) {
+		give_pages(vi, list);
+		return -ENOMEM;
 	}
-	if (unlikely(vi->num > vi->max))
-		vi->max = vi->num;
-	vi->rvq->vq_ops->kick(vi->rvq);
+	p = page_address(first);
+
+	/* vi->rx_sg[0], vi->rx_sg[1] share the same page */
+	/* a separated vi->rx_sg[0] for virtio_net_hdr only due to QEMU bug */
+	sg_set_buf(&vi->rx_sg[0], p, sizeof(struct virtio_net_hdr));
+
+	/* vi->rx_sg[1] for data packet, from offset */
+	offset = sizeof(struct padded_vnet_hdr);
+	sg_set_buf(&vi->rx_sg[1], p + offset, PAGE_SIZE - offset);
+
+	/* chain first in list head */
+	first->private = (unsigned long)list;
+	err = vi->rvq->vq_ops->add_buf(vi->rvq, vi->rx_sg, 0, MAX_SKB_FRAGS + 2,
+				       first);
+	if (err < 0)
+		give_pages(vi, first);
+
+	return err;
 }
 
-static void try_fill_recv(struct virtnet_info *vi)
+static int add_recvbuf_mergeable(struct virtnet_info *vi, gfp_t gfp)
 {
-	struct sk_buff *skb;
-	struct scatterlist sg[1];
+	struct page *page;
 	int err;
 
-	if (!vi->mergeable_rx_bufs) {
-		try_fill_recv_maxbufs(vi);
-		return;
-	}
-
-	for (;;) {
-		skb_frag_t *f;
-
-		skb = netdev_alloc_skb(vi->dev, GOOD_COPY_LEN + NET_IP_ALIGN);
-		if (unlikely(!skb))
-			break;
+	page = get_a_page(vi, gfp);
+	if (!page)
+		return -ENOMEM;
 
-		skb_reserve(skb, NET_IP_ALIGN);
+	sg_init_one(vi->rx_sg, page_address(page), PAGE_SIZE);
 
-		f = &skb_shinfo(skb)->frags[0];
-		f->page = get_a_page(vi, GFP_ATOMIC);
-		if (!f->page) {
-			kfree_skb(skb);
-			break;
-		}
+	err = vi->rvq->vq_ops->add_buf(vi->rvq, vi->rx_sg, 0, 1, page);
+	if (err < 0)
+		give_pages(vi, page);
 
-		f->page_offset = 0;
-		f->size = PAGE_SIZE;
+	return err;
+}
 
-		skb_shinfo(skb)->nr_frags++;
+/* Returns false if we couldn't fill entirely (OOM). */
+static bool try_fill_recv(struct virtnet_info *vi, gfp_t gfp)
+{
+	int err;
+	bool oom = false;
 
-		sg_init_one(sg, page_address(f->page), PAGE_SIZE);
-		skb_queue_head(&vi->recv, skb);
+	do {
+		if (vi->mergeable_rx_bufs)
+			err = add_recvbuf_mergeable(vi, gfp);
+		else if (vi->big_packets)
+			err = add_recvbuf_big(vi, gfp);
+		else
+			err = add_recvbuf_small(vi, gfp);
 
-		err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, 1, skb);
-		if (err) {
-			skb_unlink(skb, &vi->recv);
-			kfree_skb(skb);
+		if (err < 0) {
+			oom = true;
 			break;
 		}
-		vi->num++;
-	}
+		++vi->num;
+	} while (err > 0);
 	if (unlikely(vi->num > vi->max))
 		vi->max = vi->num;
 	vi->rvq->vq_ops->kick(vi->rvq);
+	return !oom;
 }
 
 static void skb_recv_done(struct virtqueue *rvq)
@@ -385,31 +447,46 @@ static void skb_recv_done(struct virtqueue *rvq)
 	}
 }
 
+static void refill_work(struct work_struct *work)
+{
+	struct virtnet_info *vi;
+	bool still_empty;
+
+	vi = container_of(work, struct virtnet_info, refill.work);
+	napi_disable(&vi->napi);
+	still_empty = !try_fill_recv(vi, GFP_KERNEL);
+	napi_enable(&vi->napi);
+
+	/* In theory, this can happen: if we don't get any buffers in
+	 * we will *never* try to fill again. */
+	if (still_empty)
+		schedule_delayed_work(&vi->refill, HZ/2);
+}
+
 static int virtnet_poll(struct napi_struct *napi, int budget)
 {
 	struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
-	struct sk_buff *skb = NULL;
+	void *buf;
 	unsigned int len, received = 0;
 
 again:
 	while (received < budget &&
-	       (skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
-		__skb_unlink(skb, &vi->recv);
-		receive_skb(vi->dev, skb, len);
-		vi->num--;
+	       (buf = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
+		receive_buf(vi->dev, buf, len);
+		--vi->num;
 		received++;
 	}
 
-	/* FIXME: If we oom and completely run out of inbufs, we need
-	 * to start a timer trying to fill more. */
-	if (vi->num < vi->max / 2)
-		try_fill_recv(vi);
+	if (vi->num < vi->max / 2) {
+		if (!try_fill_recv(vi, GFP_ATOMIC))
+			schedule_delayed_work(&vi->refill, 0);
+	}
 
 	/* Out of packets? */
 	if (received < budget) {
 		napi_complete(napi);
-		if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq))
-		    && napi_schedule_prep(napi)) {
+		if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq)) &&
+		    napi_schedule_prep(napi)) {
 			vi->rvq->vq_ops->disable_cb(vi->rvq);
 			__napi_schedule(napi);
 			goto again;
@@ -419,151 +496,112 @@ again:
 	return received;
 }
 
-static void free_old_xmit_skbs(struct virtnet_info *vi)
+static unsigned int free_old_xmit_skbs(struct virtnet_info *vi)
 {
 	struct sk_buff *skb;
-	unsigned int len;
+	unsigned int len, tot_sgs = 0;
 
 	while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
 		pr_debug("Sent skb %p\n", skb);
-		__skb_unlink(skb, &vi->send);
 		vi->dev->stats.tx_bytes += skb->len;
 		vi->dev->stats.tx_packets++;
-		kfree_skb(skb);
+		tot_sgs += skb_vnet_hdr(skb)->num_sg;
+		dev_kfree_skb_any(skb);
 	}
-}
-
-/* If the virtio transport doesn't always notify us when all in-flight packets
- * are consumed, we fall back to using this function on a timer to free them. */
-static void xmit_free(unsigned long data)
-{
-	struct virtnet_info *vi = (void *)data;
-
-	netif_tx_lock(vi->dev);
-
-	free_old_xmit_skbs(vi);
-
-	if (!skb_queue_empty(&vi->send))
-		mod_timer(&vi->xmit_free_timer, jiffies + (HZ/10));
-
-	netif_tx_unlock(vi->dev);
+	return tot_sgs;
 }
 
 static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
 {
-	int num, err;
-	struct scatterlist sg[2+MAX_SKB_FRAGS];
-	struct virtio_net_hdr_mrg_rxbuf *mhdr = skb_vnet_hdr(skb);
-	struct virtio_net_hdr *hdr = skb_vnet_hdr(skb);
+	struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
 	const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
 
-	sg_init_table(sg, 2+MAX_SKB_FRAGS);
-
 	pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
 
 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
-		hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
-		hdr->csum_start = skb->csum_start - skb_headroom(skb);
-		hdr->csum_offset = skb->csum_offset;
+		hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
+		hdr->hdr.csum_start = skb->csum_start - skb_headroom(skb);
+		hdr->hdr.csum_offset = skb->csum_offset;
 	} else {
-		hdr->flags = 0;
-		hdr->csum_offset = hdr->csum_start = 0;
+		hdr->hdr.flags = 0;
+		hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
 	}
 
 	if (skb_is_gso(skb)) {
-		hdr->hdr_len = skb_headlen(skb);
-		hdr->gso_size = skb_shinfo(skb)->gso_size;
+		hdr->hdr.hdr_len = skb_headlen(skb);
+		hdr->hdr.gso_size = skb_shinfo(skb)->gso_size;
 		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
-			hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
+			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 		else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
-			hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
+			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 		else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
-			hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
+			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
 		else
 			BUG();
 		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
-			hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
+			hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 	} else {
-		hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
-		hdr->gso_size = hdr->hdr_len = 0;
+		hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
+		hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
 	}
 
-	mhdr->num_buffers = 0;
+	hdr->mhdr.num_buffers = 0;
 
 	/* Encode metadata header at front. */
 	if (vi->mergeable_rx_bufs)
-		sg_set_buf(sg, mhdr, sizeof(*mhdr));
+		sg_set_buf(vi->tx_sg, &hdr->mhdr, sizeof hdr->mhdr);
 	else
-		sg_set_buf(sg, hdr, sizeof(*hdr));
+		sg_set_buf(vi->tx_sg, &hdr->hdr, sizeof hdr->hdr);
 
-	num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
-
-	err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
-	if (!err && !vi->free_in_tasklet)
-		mod_timer(&vi->xmit_free_timer, jiffies + (HZ/10));
-
-	return err;
-}
-
-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;
-	}
-	if (vi->free_in_tasklet)
-		free_old_xmit_skbs(vi);
-	netif_tx_unlock_bh(vi->dev);
+	hdr->num_sg = skb_to_sgvec(skb, vi->tx_sg + 1, 0, skb->len) + 1;
+	return vi->svq->vq_ops->add_buf(vi->svq, vi->tx_sg, hdr->num_sg,
+					0, skb);
 }
 
-static int start_xmit(struct sk_buff *skb, struct net_device *dev)
+static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct virtnet_info *vi = netdev_priv(dev);
+	int capacity;
 
 again:
 	/* Free up any pending old buffers before queueing new ones. */
 	free_old_xmit_skbs(vi);
 
-	/* If we has a buffer left over from last time, send it now. */
-	if (unlikely(vi->last_xmit_skb) &&
-	    xmit_skb(vi, vi->last_xmit_skb) != 0)
-		goto stop_queue;
+	/* Try to transmit */
+	capacity = xmit_skb(vi, skb);
 
-	vi->last_xmit_skb = NULL;
-
-	/* Put new one in send queue and do transmit */
-	if (likely(skb)) {
-		__skb_queue_head(&vi->send, skb);
-		if (xmit_skb(vi, skb) != 0) {
-			vi->last_xmit_skb = skb;
-			skb = NULL;
-			goto stop_queue;
+	/* This can happen with OOM and indirect buffers. */
+	if (unlikely(capacity < 0)) {
+		netif_stop_queue(dev);
+		dev_warn(&dev->dev, "Unexpected full queue\n");
+		if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
+			vi->svq->vq_ops->disable_cb(vi->svq);
+			netif_start_queue(dev);
+			goto again;
 		}
+		return NETDEV_TX_BUSY;
 	}
-done:
 	vi->svq->vq_ops->kick(vi->svq);
-	return NETDEV_TX_OK;
-
-stop_queue:
-	pr_debug("%s: virtio not prepared to send\n", dev->name);
-	netif_stop_queue(dev);
 
-	/* Activate callback for using skbs: if this returns false it
-	 * means some were used in the meantime. */
-	if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
-		vi->svq->vq_ops->disable_cb(vi->svq);
-		netif_start_queue(dev);
-		goto again;
-	}
-	if (skb) {
-		/* Drop this skb: we only queue one. */
-		vi->dev->stats.tx_dropped++;
-		kfree_skb(skb);
+	/* Don't wait up for transmitted skbs to be freed. */
+	skb_orphan(skb);
+	nf_reset(skb);
+
+	/* Apparently nice girls don't return TX_BUSY; stop the queue
+	 * before it gets out of hand.  Naturally, this wastes entries. */
+	if (capacity < 2+MAX_SKB_FRAGS) {
+		netif_stop_queue(dev);
+		if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
+			/* More just got used, free them then recheck. */
+			capacity += free_old_xmit_skbs(vi);
+			if (capacity >= 2+MAX_SKB_FRAGS) {
+				netif_start_queue(dev);
+				vi->svq->vq_ops->disable_cb(vi->svq);
+			}
+		}
 	}
-	goto done;
+
+	return NETDEV_TX_OK;
 }
 
 static int virtnet_set_mac_address(struct net_device *dev, void *p)
@@ -640,7 +678,7 @@ static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
 		sg_set_buf(&sg[i + 1], sg_virt(s), s->length);
 	sg_set_buf(&sg[out + in - 1], &status, sizeof(status));
 
-	BUG_ON(vi->cvq->vq_ops->add_buf(vi->cvq, sg, out, in, vi));
+	BUG_ON(vi->cvq->vq_ops->add_buf(vi->cvq, sg, out, in, vi) < 0);
 
 	vi->cvq->vq_ops->kick(vi->cvq);
 
@@ -680,8 +718,9 @@ static void virtnet_set_rx_mode(struct net_device *dev)
 	struct scatterlist sg[2];
 	u8 promisc, allmulti;
 	struct virtio_net_ctrl_mac *mac_data;
-	struct dev_addr_list *addr;
 	struct netdev_hw_addr *ha;
+	int uc_count;
+	int mc_count;
 	void *buf;
 	int i;
 
@@ -708,9 +747,12 @@ static void virtnet_set_rx_mode(struct net_device *dev)
 		dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
 			 allmulti ? "en" : "dis");
 
+	uc_count = netdev_uc_count(dev);
+	mc_count = netdev_mc_count(dev);
 	/* MAC filter - use one buffer for both lists */
-	mac_data = buf = kzalloc(((dev->uc_count + dev->mc_count) * ETH_ALEN) +
-				 (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
+	buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
+		      (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
+	mac_data = buf;
 	if (!buf) {
 		dev_warn(&dev->dev, "No memory for MAC address buffer\n");
 		return;
@@ -719,24 +761,24 @@ static void virtnet_set_rx_mode(struct net_device *dev)
 	sg_init_table(sg, 2);
 
 	/* Store the unicast list and count in the front of the buffer */
-	mac_data->entries = dev->uc_count;
+	mac_data->entries = uc_count;
 	i = 0;
-	list_for_each_entry(ha, &dev->uc_list, list)
+	netdev_for_each_uc_addr(ha, dev)
 		memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
 
 	sg_set_buf(&sg[0], mac_data,
-		   sizeof(mac_data->entries) + (dev->uc_count * ETH_ALEN));
+		   sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
 
 	/* multicast list and count fill the end */
-	mac_data = (void *)&mac_data->macs[dev->uc_count][0];
+	mac_data = (void *)&mac_data->macs[uc_count][0];
 
-	mac_data->entries = dev->mc_count;
-	addr = dev->mc_list;
-	for (i = 0; i < dev->mc_count; i++, addr = addr->next)
-		memcpy(&mac_data->macs[i][0], addr->da_addr, ETH_ALEN);
+	mac_data->entries = mc_count;
+	i = 0;
+	netdev_for_each_mc_addr(ha, dev)
+		memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
 
 	sg_set_buf(&sg[1], mac_data,
-		   sizeof(mac_data->entries) + (dev->mc_count * ETH_ALEN));
+		   sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
 
 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
 				  VIRTIO_NET_CTRL_MAC_TABLE_SET,
@@ -770,10 +812,11 @@ static void virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid)
 		dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
 }
 
-static struct ethtool_ops virtnet_ethtool_ops = {
+static const struct ethtool_ops virtnet_ethtool_ops = {
 	.set_tx_csum = virtnet_set_tx_csum,
 	.set_sg = ethtool_op_set_sg,
 	.set_tso = ethtool_op_set_tso,
+	.set_ufo = ethtool_op_set_ufo,
 	.get_link = ethtool_op_get_link,
 };
 
@@ -893,15 +936,14 @@ static int virtnet_probe(struct virtio_device *vdev)
 	vi->vdev = vdev;
 	vdev->priv = vi;
 	vi->pages = NULL;
-
-	/* If they give us a callback when all buffers are done, we don't need
-	 * the timer. */
-	vi->free_in_tasklet = virtio_has_feature(vdev,VIRTIO_F_NOTIFY_ON_EMPTY);
+	INIT_DELAYED_WORK(&vi->refill, refill_work);
+	sg_init_table(vi->rx_sg, ARRAY_SIZE(vi->rx_sg));
+	sg_init_table(vi->tx_sg, ARRAY_SIZE(vi->tx_sg));
 
 	/* If we can receive ANY GSO packets, we must allocate large ones. */
-	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4)
-	    || virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6)
-	    || virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
+	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
+	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
+	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN))
 		vi->big_packets = true;
 
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
@@ -925,15 +967,6 @@ static int virtnet_probe(struct virtio_device *vdev)
 			dev->features |= NETIF_F_HW_VLAN_FILTER;
 	}
 
-	/* Initialize our empty receive and send queues. */
-	skb_queue_head_init(&vi->recv);
-	skb_queue_head_init(&vi->send);
-
-	tasklet_init(&vi->tasklet, xmit_tasklet, (unsigned long)vi);
-
-	if (!vi->free_in_tasklet)
-		setup_timer(&vi->xmit_free_timer, xmit_free, (unsigned long)vi);
-
 	err = register_netdev(dev);
 	if (err) {
 		pr_debug("virtio_net: registering device failed\n");
@@ -941,7 +974,7 @@ static int virtnet_probe(struct virtio_device *vdev)
 	}
 
 	/* Last of all, set up some receive buffers. */
-	try_fill_recv(vi);
+	try_fill_recv(vi, GFP_KERNEL);
 
 	/* If we didn't even get one input buffer, we're useless. */
 	if (vi->num == 0) {
@@ -958,6 +991,7 @@ static int virtnet_probe(struct virtio_device *vdev)
 
 unregister:
 	unregister_netdev(dev);
+	cancel_delayed_work_sync(&vi->refill);
 free_vqs:
 	vdev->config->del_vqs(vdev);
 free:
@@ -965,27 +999,41 @@ free:
 	return err;
 }
 
-static void virtnet_remove(struct virtio_device *vdev)
+static void free_unused_bufs(struct virtnet_info *vi)
+{
+	void *buf;
+	while (1) {
+		buf = vi->svq->vq_ops->detach_unused_buf(vi->svq);
+		if (!buf)
+			break;
+		dev_kfree_skb(buf);
+	}
+	while (1) {
+		buf = vi->rvq->vq_ops->detach_unused_buf(vi->rvq);
+		if (!buf)
+			break;
+		if (vi->mergeable_rx_bufs || vi->big_packets)
+			give_pages(vi, buf);
+		else
+			dev_kfree_skb(buf);
+		--vi->num;
+	}
+	BUG_ON(vi->num != 0);
+}
+
+static void __devexit virtnet_remove(struct virtio_device *vdev)
 {
 	struct virtnet_info *vi = vdev->priv;
-	struct sk_buff *skb;
 
 	/* Stop all the virtqueues. */
 	vdev->config->reset(vdev);
 
-	if (!vi->free_in_tasklet)
-		del_timer_sync(&vi->xmit_free_timer);
-
-	/* Free our skbs in send and recv queues, if any. */
-	while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
-		kfree_skb(skb);
-		vi->num--;
-	}
-	__skb_queue_purge(&vi->send);
-
-	BUG_ON(vi->num != 0);
 
 	unregister_netdev(vi->dev);
+	cancel_delayed_work_sync(&vi->refill);
+
+	/* Free unused buffers in both send and recv, if any. */
+	free_unused_bufs(vi);
 
 	vdev->config->del_vqs(vi->vdev);
 
@@ -1005,13 +1053,12 @@ static unsigned int features[] = {
 	VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
 	VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
 	VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
-	VIRTIO_NET_F_GUEST_ECN, /* We don't yet handle UFO input. */
+	VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
 	VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
 	VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
-	VIRTIO_F_NOTIFY_ON_EMPTY,
 };
 
-static struct virtio_driver virtio_net = {
+static struct virtio_driver virtio_net_driver = {
 	.feature_table = features,
 	.feature_table_size = ARRAY_SIZE(features),
 	.driver.name =	KBUILD_MODNAME,
@@ -1024,12 +1071,12 @@ static struct virtio_driver virtio_net = {
 
 static int __init init(void)
 {
-	return register_virtio_driver(&virtio_net);
+	return register_virtio_driver(&virtio_net_driver);
 }
 
 static void __exit fini(void)
 {
-	unregister_virtio_driver(&virtio_net);
+	unregister_virtio_driver(&virtio_net_driver);
 }
 module_init(init);
 module_exit(fini);