Subject: Re: [RFC PATCH v2 09/19] net: Add vbus_enet driver

From: Stephen Hemminger <[email-masked]>
Date: Thu, 9 Apr 2009 09:37:10 -0700

On Thu, 09 Apr 2009 12:31:29 -0400
Gregory Haskins <[email-masked]> wrote:

> Signed-off-by: Gregory Haskins <[email-masked]>
> ---
> 
>  drivers/net/Kconfig     |   13 +
>  drivers/net/Makefile    |    1 
>  drivers/net/vbus-enet.c |  680 +++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 694 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/net/vbus-enet.c
> 
> diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
> index 62d732a..ac9dabd 100644
> --- a/drivers/net/Kconfig
> +++ b/drivers/net/Kconfig
> @@ -3099,4 +3099,17 @@ config VIRTIO_NET
>  	  This is the virtual network driver for virtio.  It can be used with
>            lguest or QEMU based VMMs (like KVM or Xen).  Say Y or M.
>  
> +config VBUS_ENET
> +	tristate "Virtual Ethernet Driver"
> +	depends on VBUS_DRIVERS
> +	help
> +	   A virtualized 802.x network device based on the VBUS interface.
> +	   It can be used with any hypervisor/kernel that supports the
> +	   vbus protocol.
> +
> +config VBUS_ENET_DEBUG
> +        bool "Enable Debugging"
> +	depends on VBUS_ENET
> +	default n
> +
>  endif # NETDEVICES
> diff --git a/drivers/net/Makefile b/drivers/net/Makefile
> index 471baaf..61db928 100644
> --- a/drivers/net/Makefile
> +++ b/drivers/net/Makefile
> @@ -264,6 +264,7 @@ obj-$(CONFIG_FS_ENET) += fs_enet/
>  obj-$(CONFIG_NETXEN_NIC) += netxen/
>  obj-$(CONFIG_NIU) += niu.o
>  obj-$(CONFIG_VIRTIO_NET) += virtio_net.o
> +obj-$(CONFIG_VBUS_ENET) += vbus-enet.o
>  obj-$(CONFIG_SFC) += sfc/
>  
>  obj-$(CONFIG_WIMAX) += wimax/
> diff --git a/drivers/net/vbus-enet.c b/drivers/net/vbus-enet.c
> new file mode 100644
> index 0000000..3779f77
> --- /dev/null
> +++ b/drivers/net/vbus-enet.c
> @@ -0,0 +1,680 @@
> +/*
> + * vbus_enet - A virtualized 802.x network device based on the VBUS interface
> + *
> + * Copyright (C) 2009 Novell, Gregory Haskins <[email-masked]>
> + *
> + * Derived from the SNULL example from the book "Linux Device Drivers" by
> + * Alessandro Rubini, Jonathan Corbet, and Greg Kroah-Hartman, published
> + * by O'Reilly & Associates.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/moduleparam.h>
> +
> +#include <linux/sched.h>
> +#include <linux/kernel.h>
> +#include <linux/slab.h>
> +#include <linux/errno.h>
> +#include <linux/types.h>
> +#include <linux/interrupt.h>
> +
> +#include <linux/in.h>
> +#include <linux/netdevice.h>
> +#include <linux/etherdevice.h>
> +#include <linux/ip.h>
> +#include <linux/tcp.h>
> +#include <linux/skbuff.h>
> +#include <linux/ioq.h>
> +#include <linux/vbus_driver.h>
> +
> +#include <linux/in6.h>
> +#include <asm/checksum.h>
> +
> +#include <linux/venet.h>
> +
> +MODULE_AUTHOR("Gregory Haskins");
> +MODULE_LICENSE("GPL");

MODULE_DESCRIPTION ? 
MODULE_VERSION ?

> +static int napi_weight = 128;
> +module_param(napi_weight, int, 0444);
Already accessible through sysfs

> +static int rx_ringlen = 256;
> +module_param(rx_ringlen, int, 0444);

API for ring length exists via ethtool. If you used this
then there would be no need for device special parameter.

> +static int tx_ringlen = 256;
> +module_param(tx_ringlen, int, 0444);
> +
> +#undef PDEBUG             /* undef it, just in case */
> +#ifdef VBUS_ENET_DEBUG
> +#  define PDEBUG(fmt, args...) printk(KERN_DEBUG "vbus_enet: " fmt, ## args)
> +#else
> +#  define PDEBUG(fmt, args...) /* not debugging: nothing */
> +#endif

Why reinvent pr_debug()?

> +
> +struct vbus_enet_queue {
> +	struct ioq              *queue;
> +	struct ioq_notifier      notifier;
> +};
> +
> +struct vbus_enet_priv {
> +	spinlock_t                 lock;
> +	struct net_device         *dev;
> +	struct vbus_device_proxy  *vdev;
> +	struct napi_struct         napi;
> +	struct vbus_enet_queue     rxq;
> +	struct vbus_enet_queue     txq;
> +	struct tasklet_struct      txtask;
> +};
> +
> +static struct vbus_enet_priv *
> +napi_to_priv(struct napi_struct *napi)
> +{
> +	return container_of(napi, struct vbus_enet_priv, napi);
> +}
> +
> +static int
> +queue_init(struct vbus_enet_priv *priv,
> +	   struct vbus_enet_queue *q,
> +	   int qid,
> +	   size_t ringsize,
> +	   void (*func)(struct ioq_notifier *))
> +{
> +	struct vbus_device_proxy *dev = priv->vdev;
> +	int ret;
> +
> +	ret = vbus_driver_ioq_alloc(dev, qid, 0, ringsize, &q->queue);
> +	if (ret < 0)
> +		panic("ioq_alloc failed: %d\n", ret);
> +
> +	if (func) {
> +		q->notifier.signal = func;
> +		q->queue->notifier = &q->notifier;
> +	}
> +
> +	return 0;
> +}
> +
> +static int
> +devcall(struct vbus_enet_priv *priv, u32 func, void *data, size_t len)
> +{
> +	struct vbus_device_proxy *dev = priv->vdev;
> +
> +	return dev->ops->call(dev, func, data, len, 0);
> +}
> +
> +/*
> + * ---------------
> + * rx descriptors
> + * ---------------
> + */
> +
> +static void
> +rxdesc_alloc(struct ioq_ring_desc *desc, size_t len)
> +{
> +	struct sk_buff *skb;
> +
> +	len += ETH_HLEN;
> +
> +	skb = dev_alloc_skb(len + 2);
> +	BUG_ON(!skb);
> +
> +	skb_reserve(skb, 2); /* align IP on 16B boundary */
Use NET_IP_ALIGN rather than 2

use netdev_alloc_skb because it NUMA aware.

> +
> +	desc->cookie = (u64)skb;
> +	desc->ptr    = (u64)__pa(skb->data);
> +	desc->len    = len; /* total length  */
> +	desc->valid  = 1;
> +}
> +
> +static void
> +rx_setup(struct vbus_enet_priv *priv)
> +{
> +	struct ioq *ioq = priv->rxq.queue;
> +	struct ioq_iterator iter;
> +	int ret;
> +
> +	/*
> +	 * We want to iterate on the "valid" index.  By default the iterator
> +	 * will not "autoupdate" which means it will not hypercall the host
> +	 * with our changes.  This is good, because we are really just
> +	 * initializing stuff here anyway.  Note that you can always manually
> +	 * signal the host with ioq_signal() if the autoupdate feature is not
> +	 * used.
> +	 */
> +	ret = ioq_iter_init(ioq, &iter, ioq_idxtype_valid, 0);
> +	BUG_ON(ret < 0);

Why not doing proper initialization error handling, I.e fail the
attempt to bring device up with error code (-ENOMEM)...

> +	/*
> +	 * Seek to the tail of the valid index (which should be our first
> +	 * item, since the queue is brand-new)
> +	 */
> +	ret = ioq_iter_seek(&iter, ioq_seek_tail, 0, 0);
> +	BUG_ON(ret < 0);
> +
> +	/*
> +	 * Now populate each descriptor with an empty SKB and mark it valid
> +	 */
> +	while (!iter.desc->valid) {
> +		rxdesc_alloc(iter.desc, priv->dev->mtu);
> +
> +		/*
> +		 * This push operation will simultaneously advance the
> +		 * valid-head index and increment our position in the queue
> +		 * by one.
> +		 */
> +		ret = ioq_iter_push(&iter, 0);
> +		BUG_ON(ret < 0);
> +	}
> +}
> +
> +static void
> +rx_teardown(struct vbus_enet_priv *priv)
> +{
> +	struct ioq *ioq = priv->rxq.queue;
> +	struct ioq_iterator iter;
> +	int ret;
> +
> +	ret = ioq_iter_init(ioq, &iter, ioq_idxtype_valid, 0);
> +	BUG_ON(ret < 0);
> +
> +	ret = ioq_iter_seek(&iter, ioq_seek_head, 0, 0);
> +	BUG_ON(ret < 0);
> +
> +	/*
> +	 * free each valid descriptor
> +	 */
> +	while (iter.desc->valid) {
> +		struct sk_buff *skb = (struct sk_buff *)iter.desc->cookie;
> +
> +		iter.desc->valid = 0;
> +		wmb();
> +
> +		iter.desc->ptr = 0;
> +		iter.desc->cookie = 0;
> +
> +		ret = ioq_iter_pop(&iter, 0);
> +		BUG_ON(ret < 0);
> +
> +		dev_kfree_skb(skb);
> +	}
> +}
> +
> +/*
> + * Open and close
> + */
> +
> +static int
> +vbus_enet_open(struct net_device *dev)
> +{
> +	struct vbus_enet_priv *priv = netdev_priv(dev);
> +	int ret;
> +
> +	ret = devcall(priv, VENET_FUNC_LINKUP, NULL, 0);
> +	BUG_ON(ret < 0);
> +
> +	napi_enable(&priv->napi);
> +
> +	return 0;
> +}
> +
> +static int
> +vbus_enet_stop(struct net_device *dev)
> +{
> +	struct vbus_enet_priv *priv = netdev_priv(dev);
> +	int ret;
> +
> +	napi_disable(&priv->napi);
> +
> +	ret = devcall(priv, VENET_FUNC_LINKDOWN, NULL, 0);
> +	BUG_ON(ret < 0);
> +
> +	return 0;
> +}
> +
> +/*
> + * Configuration changes (passed on by ifconfig)
> + */
> +static int
> +vbus_enet_config(struct net_device *dev, struct ifmap *map)
> +{
> +	if (dev->flags & IFF_UP) /* can't act on a running interface */
> +		return -EBUSY;
> +
> +	/* Don't allow changing the I/O address */
> +	if (map->base_addr != dev->base_addr) {
> +		printk(KERN_WARNING "vbus_enet: Can't change I/O address\n");
> +		return -EOPNOTSUPP;
> +	}
> +
> +	/* ignore other fields */
> +	return 0;
> +}
> +
> +static void
> +vbus_enet_schedule_rx(struct vbus_enet_priv *priv)
> +{
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&priv->lock, flags);
> +
> +	if (netif_rx_schedule_prep(&priv->napi)) {
> +		/* Disable further interrupts */
> +		ioq_notify_disable(priv->rxq.queue, 0);
> +		__netif_rx_schedule(&priv->napi);
> +	}
> +
> +	spin_unlock_irqrestore(&priv->lock, flags);
> +}
> +
> +static int
> +vbus_enet_change_mtu(struct net_device *dev, int new_mtu)
> +{
> +	struct vbus_enet_priv *priv = netdev_priv(dev);
> +	int ret;
> +
> +	dev->mtu = new_mtu;
> +
> +	/*
> +	 * FLUSHRX will cause the device to flush any outstanding
> +	 * RX buffers.  They will appear to come in as 0 length
> +	 * packets which we can simply discard and replace with new_mtu
> +	 * buffers for the future.
> +	 */
> +	ret = devcall(priv, VENET_FUNC_FLUSHRX, NULL, 0);
> +	BUG_ON(ret < 0);
> +
> +	vbus_enet_schedule_rx(priv);
> +
> +	return 0;
> +}
> +
> +/*
> + * The poll implementation.
> + */
> +static int
> +vbus_enet_poll(struct napi_struct *napi, int budget)
> +{
> +	struct vbus_enet_priv *priv = napi_to_priv(napi);
> +	int npackets = 0;
> +	struct ioq_iterator iter;
> +	int ret;
> +
> +	PDEBUG("%lld: polling...\n", priv->vdev->id);
> +
> +	/* We want to iterate on the head of the in-use index */
> +	ret = ioq_iter_init(priv->rxq.queue, &iter, ioq_idxtype_inuse,
> +			    IOQ_ITER_AUTOUPDATE);
> +	BUG_ON(ret < 0);
> +
> +	ret = ioq_iter_seek(&iter, ioq_seek_head, 0, 0);
> +	BUG_ON(ret < 0);
> +
> +	/*
> +	 * We stop if we have met the quota or there are no more packets.
> +	 * The EOM is indicated by finding a packet that is still owned by
> +	 * the south side
> +	 */
> +	while ((npackets < budget) && (!iter.desc->sown)) {
> +		struct sk_buff *skb = (struct sk_buff *)iter.desc->cookie;
> +
> +		if (iter.desc->len) {
> +			skb_put(skb, iter.desc->len);
> +
> +			/* Maintain stats */
> +			npackets++;
> +			priv->dev->stats.rx_packets++;
> +			priv->dev->stats.rx_bytes += iter.desc->len;
> +
> +			/* Pass the buffer up to the stack */
> +			skb->dev      = priv->dev;
> +			skb->protocol = eth_type_trans(skb, priv->dev);
> +			netif_receive_skb(skb);
> +
> +			mb();
> +		} else
> +			/*
> +			 * the device may send a zero-length packet when its
> +			 * flushing references on the ring.  We can just drop
> +			 * these on the floor
> +			 */
> +			dev_kfree_skb(skb);
> +
> +		/* Grab a new buffer to put in the ring */
> +		rxdesc_alloc(iter.desc, priv->dev->mtu);
> +
> +		/* Advance the in-use tail */
> +		ret = ioq_iter_pop(&iter, 0);
> +		BUG_ON(ret < 0);
> +	}
> +
> +	PDEBUG("%lld poll: %d packets received\n", priv->vdev->id, npackets);
> +
> +	/*
> +	 * If we processed all packets, we're done; tell the kernel and
> +	 * reenable ints
> +	 */
> +	if (ioq_empty(priv->rxq.queue, ioq_idxtype_inuse)) {
> +		netif_rx_complete(napi);
> +		ioq_notify_enable(priv->rxq.queue, 0);
> +		ret = 0;
> +	} else
> +		/* We couldn't process everything. */
> +		ret = 1;
> +
> +	return ret;
> +}
> +
> +/*
> + * Transmit a packet (called by the kernel)
> + */
> +static int
> +vbus_enet_tx_start(struct sk_buff *skb, struct net_device *dev)
> +{
> +	struct vbus_enet_priv *priv = netdev_priv(dev);
> +	struct ioq_iterator    iter;
> +	int ret;
> +	unsigned long flags;
> +
> +	PDEBUG("%lld: sending %d bytes\n", priv->vdev->id, skb->len);
> +
> +	spin_lock_irqsave(&priv->lock, flags);
> +
> +	if (ioq_full(priv->txq.queue, ioq_idxtype_valid)) {
> +		/*
> +		 * We must flow-control the kernel by disabling the
> +		 * queue
> +		 */
> +		spin_unlock_irqrestore(&priv->lock, flags);
> +		netif_stop_queue(dev);
> +		printk(KERN_ERR "VBUS_ENET: tx on full queue bug "	\
> +		       "on device %lld\n", priv->vdev->id);
> +		return 1;
> +	}
> +
> +	/*
> +	 * We want to iterate on the tail of both the "inuse" and "valid" index
> +	 * so we specify the "both" index
> +	 */
> +	ret = ioq_iter_init(priv->txq.queue, &iter, ioq_idxtype_both,
> +			    IOQ_ITER_AUTOUPDATE);
> +	BUG_ON(ret < 0);
> +
> +	ret = ioq_iter_seek(&iter, ioq_seek_tail, 0, 0);
> +	BUG_ON(ret < 0);
> +	BUG_ON(iter.desc->sown);
> +
> +	/*
> +	 * We simply put the skb right onto the ring.  We will get an interrupt
> +	 * later when the data has been consumed and we can reap the pointers
> +	 * at that time
> +	 */
> +	iter.desc->cookie = (u64)skb;
> +	iter.desc->len = (u64)skb->len;
> +	iter.desc->ptr = (u64)__pa(skb->data);
> +	iter.desc->valid  = 1;
> +
> +	priv->dev->stats.tx_packets++;
> +	priv->dev->stats.tx_bytes += skb->len;
> +
> +	/*
> +	 * This advances both indexes together implicitly, and then
> +	 * signals the south side to consume the packet
> +	 */
> +	ret = ioq_iter_push(&iter, 0);
> +	BUG_ON(ret < 0);
> +
> +	dev->trans_start = jiffies; /* save the timestamp */
> +
> +	if (ioq_full(priv->txq.queue, ioq_idxtype_valid)) {
> +		/*
> +		 * If the queue is congested, we must flow-control the kernel
> +		 */
> +		PDEBUG("%lld: backpressure tx queue\n", priv->vdev->id);
> +		netif_stop_queue(dev);
> +	}
> +
> +	spin_unlock_irqrestore(&priv->lock, flags);
> +
> +	return 0;
> +}
> +
> +/*
> + * reclaim any outstanding completed tx packets
> + *
> + * assumes priv->lock held
> + */
> +static void
> +vbus_enet_tx_reap(struct vbus_enet_priv *priv, int force)
> +{
> +	struct ioq_iterator iter;
> +	int ret;
> +
> +	/*
> +	 * We want to iterate on the head of the valid index, but we
> +	 * do not want the iter_pop (below) to flip the ownership, so
> +	 * we set the NOFLIPOWNER option
> +	 */
> +	ret = ioq_iter_init(priv->txq.queue, &iter, ioq_idxtype_valid,
> +			    IOQ_ITER_NOFLIPOWNER);
> +	BUG_ON(ret < 0);
> +
> +	ret = ioq_iter_seek(&iter, ioq_seek_head, 0, 0);
> +	BUG_ON(ret < 0);
> +
> +	/*
> +	 * We are done once we find the first packet either invalid or still
> +	 * owned by the south-side
> +	 */
> +	while (iter.desc->valid && (!iter.desc->sown || force)) {
> +		struct sk_buff *skb = (struct sk_buff *)iter.desc->cookie;
> +
> +		PDEBUG("%lld: completed sending %d bytes\n",
> +		       priv->vdev->id, skb->len);
> +
> +		/* Reset the descriptor */
> +		iter.desc->valid  = 0;
> +
> +		dev_kfree_skb(skb);
> +
> +		/* Advance the valid-index head */
> +		ret = ioq_iter_pop(&iter, 0);
> +		BUG_ON(ret < 0);
> +	}
> +
> +	/*
> +	 * If we were previously stopped due to flow control, restart the
> +	 * processing
> +	 */
> +	if (netif_queue_stopped(priv->dev)
> +	    && !ioq_full(priv->txq.queue, ioq_idxtype_valid)) {
> +		PDEBUG("%lld: re-enabling tx queue\n", priv->vdev->id);
> +		netif_wake_queue(priv->dev);
> +	}
> +}
> +
> +static void
> +vbus_enet_timeout(struct net_device *dev)
> +{
> +	struct vbus_enet_priv *priv = netdev_priv(dev);
> +	unsigned long flags;
> +
> +	printk(KERN_DEBUG "VBUS_ENET %lld: Transmit timeout\n", priv->vdev->id);
> +
> +	spin_lock_irqsave(&priv->lock, flags);
> +	vbus_enet_tx_reap(priv, 0);
> +	spin_unlock_irqrestore(&priv->lock, flags);
> +}
> +
> +static void
> +rx_isr(struct ioq_notifier *notifier)
> +{
> +	struct vbus_enet_priv *priv;
> +	struct net_device  *dev;
> +
> +	priv = container_of(notifier, struct vbus_enet_priv, rxq.notifier);
> +	dev = priv->dev;
> +
> +	if (!ioq_empty(priv->rxq.queue, ioq_idxtype_inuse))
> +		vbus_enet_schedule_rx(priv);
> +}
> +
> +static void
> +deferred_tx_isr(unsigned long data)
> +{
> +	struct vbus_enet_priv *priv = (struct vbus_enet_priv *)data;
> +	unsigned long flags;
> +
> +	PDEBUG("deferred_tx_isr for %lld\n", priv->vdev->id);
> +
> +	spin_lock_irqsave(&priv->lock, flags);
> +	vbus_enet_tx_reap(priv, 0);
> +	spin_unlock_irqrestore(&priv->lock, flags);
> +
> +	ioq_notify_enable(priv->txq.queue, 0);
> +}
> +
> +static void
> +tx_isr(struct ioq_notifier *notifier)
> +{
> +       struct vbus_enet_priv *priv;
> +       unsigned long flags;
> +
> +       priv = container_of(notifier, struct vbus_enet_priv, txq.notifier);
> +
> +       PDEBUG("tx_isr for %lld\n", priv->vdev->id);
> +
> +       ioq_notify_disable(priv->txq.queue, 0);
> +       tasklet_schedule(&priv->txtask);
> +}
> +
> +static const struct net_device_ops vbus_enet_netdev_ops = {
> +	.ndo_open          = vbus_enet_open,
> +	.ndo_stop          = vbus_enet_stop,
> +	.ndo_set_config    = vbus_enet_config,
> +	.ndo_start_xmit    = vbus_enet_tx_start,
> +	.ndo_change_mtu	   = vbus_enet_change_mtu,
> +	.ndo_tx_timeout    = vbus_enet_timeout,

add .ndo_validate_addr = eth_valid_addr?
multicast list?

> +};
> +
> +/*
> + * This is called whenever a new vbus_device_proxy is added to the vbus
> + * with the matching VENET_ID
> + */
> +static int
> +vbus_enet_probe(struct vbus_device_proxy *vdev)
> +{
> +	struct net_device  *dev;
> +	struct vbus_enet_priv *priv;
> +	int ret;
> +
> +	printk(KERN_INFO "VBUS_ENET: Found new device at %lld\n", vdev->id);
> +
> +	ret = vdev->ops->open(vdev, VENET_VERSION, 0);
> +	if (ret < 0)
> +		return ret;
> +
> +	dev = alloc_etherdev(sizeof(struct vbus_enet_priv));
> +	if (!dev)
> +		return -ENOMEM;
> +
> +	priv = netdev_priv(dev);
> +
> +	spin_lock_init(&priv->lock);
> +	priv->dev  = dev;
> +	priv->vdev = vdev;
> +
> +	tasklet_init(&priv->txtask, deferred_tx_isr, (unsigned long)priv);
> +
> +	queue_init(priv, &priv->rxq, VENET_QUEUE_RX, rx_ringlen, rx_isr);
> +	queue_init(priv, &priv->txq, VENET_QUEUE_TX, tx_ringlen, tx_isr);
> +
> +	rx_setup(priv);
> +
> +	ioq_notify_enable(priv->rxq.queue, 0);  /* enable interrupts */
> +	ioq_notify_enable(priv->txq.queue, 0);
> +
> +	dev->netdev_ops     = &vbus_enet_netdev_ops;
> +	dev->watchdog_timeo = 5 * HZ;
> +
> +	netif_napi_add(dev, &priv->napi, vbus_enet_poll, napi_weight);
> +
> +	ret = devcall(priv, VENET_FUNC_MACQUERY, priv->dev->dev_addr, ETH_ALEN);
> +	if (ret < 0) {
> +		printk(KERN_INFO "VENET: Error obtaining MAC address for " \
> +		       "%lld\n",
> +		       priv->vdev->id);
> +		goto out_free;
> +	}
> +
> +	dev->features |= NETIF_F_HIGHDMA;
> +
> +	ret = register_netdev(dev);
> +	if (ret < 0) {
> +		printk(KERN_INFO "VENET: error %i registering device \"%s\"\n",
> +		       ret, dev->name);
> +		goto out_free;
> +	}
> +
> +	vdev->priv = priv;
> +
> +	return 0;
> +
> + out_free:
> +	free_netdev(dev);
> +
> +	return ret;
> +}
> +
> +static int
> +vbus_enet_remove(struct vbus_device_proxy *vdev)
> +{
> +	struct vbus_enet_priv *priv = (struct vbus_enet_priv *)vdev->priv;
> +	struct vbus_device_proxy *dev = priv->vdev;
> +
> +	unregister_netdev(priv->dev);
> +	napi_disable(&priv->napi);
> +
> +	rx_teardown(priv);
> +	vbus_enet_tx_reap(priv, 1);
> +
> +	ioq_put(priv->rxq.queue);
> +	ioq_put(priv->txq.queue);
> +
> +	dev->ops->close(dev, 0);
> +
> +	free_netdev(priv->dev);
> +
> +	return 0;
> +}
> +
> +/*
> + * Finally, the module stuff
> + */
> +
> +static struct vbus_driver_ops vbus_enet_driver_ops = {
> +	.probe  = vbus_enet_probe,
> +	.remove = vbus_enet_remove,
> +};
> +
> +static struct vbus_driver vbus_enet_driver = {
> +	.type   = VENET_TYPE,
> +	.owner  = THIS_MODULE,
> +	.ops    = &vbus_enet_driver_ops,
> +};
> +
> +static __init int
> +vbus_enet_init_module(void)
> +{
> +	printk(KERN_INFO "Virtual Ethernet: Copyright (C) 2009 Novell, Gregory Haskins\n");
> +	printk(KERN_DEBUG "VBUSENET: Using %d/%d queue depth\n",
> +	       rx_ringlen, tx_ringlen);
> +	return vbus_driver_register(&vbus_enet_driver);
> +}
> +
> +static __exit void
> +vbus_enet_cleanup(void)
> +{
> +	vbus_driver_unregister(&vbus_enet_driver);
> +}
> +
> +module_init(vbus_enet_init_module);
> +module_exit(vbus_enet_cleanup);
>