drivers/net/hyperv/netvsc_drv.c - kernel/msm-4.19 - Gitiles

 /*
  * Copyright (c) 2009, Microsoft Corporation.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
  * version 2, as published by the Free Software Foundation.
  *
  * This program is distributed in the hope it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  * more details.
  *
  * You should have received a copy of the GNU General Public License along with
  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  * Place - Suite 330, Boston, MA 02111-1307 USA.
  *
  * Authors:
  *   Haiyang Zhang <haiyangz@microsoft.com>
  *   Hank Janssen  <hjanssen@microsoft.com>
  */
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #include <linux/init.h>
 #include <linux/atomic.h>
 #include <linux/module.h>
 #include <linux/highmem.h>
 #include <linux/device.h>
 #include <linux/io.h>
 #include <linux/delay.h>
 #include <linux/netdevice.h>
 #include <linux/inetdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/skbuff.h>
 #include <linux/if_vlan.h>
 #include <linux/in.h>
 #include <linux/slab.h>
 #include <net/arp.h>
 #include <net/route.h>
 #include <net/sock.h>
 #include <net/pkt_sched.h>

 #include "hyperv_net.h"

 struct net_device_context {
 	/* point back to our device context */
 	struct hv_device *device_ctx;
 	struct delayed_work dwork;
 	struct work_struct work;
 };

 #define RING_SIZE_MIN 64
 static int ring_size = 128;
 module_param(ring_size, int, S_IRUGO);
 MODULE_PARM_DESC(ring_size, "Ring buffer size (# of pages)");

 static void do_set_multicast(struct work_struct *w)
 {
 	struct net_device_context *ndevctx =
 		container_of(w, struct net_device_context, work);
 	struct netvsc_device *nvdev;
 	struct rndis_device *rdev;

 	nvdev = hv_get_drvdata(ndevctx->device_ctx);
 	if (nvdev == NULL || nvdev->ndev == NULL)
 		return;

 	rdev = nvdev->extension;
 	if (rdev == NULL)
 		return;

 	if (nvdev->ndev->flags & IFF_PROMISC)
 		rndis_filter_set_packet_filter(rdev,
 			NDIS_PACKET_TYPE_PROMISCUOUS);
 	else
 		rndis_filter_set_packet_filter(rdev,
 			NDIS_PACKET_TYPE_BROADCAST |
 			NDIS_PACKET_TYPE_ALL_MULTICAST |
 			NDIS_PACKET_TYPE_DIRECTED);
 }

 static void netvsc_set_multicast_list(struct net_device *net)
 {
 	struct net_device_context *net_device_ctx = netdev_priv(net);

 	schedule_work(&net_device_ctx->work);
 }

 static int netvsc_open(struct net_device *net)
 {
 	struct net_device_context *net_device_ctx = netdev_priv(net);
 	struct hv_device *device_obj = net_device_ctx->device_ctx;
 	int ret = 0;

 	/* Open up the device */
 	ret = rndis_filter_open(device_obj);
 	if (ret != 0) {
 		netdev_err(net, "unable to open device (ret %d).\n", ret);
 		return ret;
 	}

 	netif_start_queue(net);

 	return ret;
 }

 static int netvsc_close(struct net_device *net)
 {
 	struct net_device_context *net_device_ctx = netdev_priv(net);
 	struct hv_device *device_obj = net_device_ctx->device_ctx;
 	int ret;

 	netif_tx_disable(net);

 	/* Make sure netvsc_set_multicast_list doesn't re-enable filter! */
 	cancel_work_sync(&net_device_ctx->work);
 	ret = rndis_filter_close(device_obj);
 	if (ret != 0)
 		netdev_err(net, "unable to close device (ret %d).\n", ret);

 	return ret;
 }

 static void netvsc_xmit_completion(void *context)
 {
 	struct hv_netvsc_packet *packet = (struct hv_netvsc_packet *)context;
 	struct sk_buff *skb = (struct sk_buff *)
 		(unsigned long)packet->completion.send.send_completion_tid;

 	kfree(packet);

 	if (skb)
 		dev_kfree_skb_any(skb);
 }

 static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
 {
 	struct net_device_context *net_device_ctx = netdev_priv(net);
 	struct hv_netvsc_packet *packet;
 	int ret;
 	unsigned int i, num_pages, npg_data;

 	/* Add multipages for skb->data and additional 2 for RNDIS */
 	npg_data = (((unsigned long)skb->data + skb_headlen(skb) - 1)
 		>> PAGE_SHIFT) - ((unsigned long)skb->data >> PAGE_SHIFT) + 1;
 	num_pages = skb_shinfo(skb)->nr_frags + npg_data + 2;

 	/* Allocate a netvsc packet based on # of frags. */
 	packet = kzalloc(sizeof(struct hv_netvsc_packet) +
 			 (num_pages * sizeof(struct hv_page_buffer)) +
 			 sizeof(struct rndis_filter_packet) +
 			 NDIS_VLAN_PPI_SIZE, GFP_ATOMIC);
 	if (!packet) {
 		/* out of memory, drop packet */
 		netdev_err(net, "unable to allocate hv_netvsc_packet\n");

 		dev_kfree_skb(skb);
 		net->stats.tx_dropped++;
 		return NETDEV_TX_OK;
 	}

 	packet->vlan_tci = skb->vlan_tci;

 	packet->extension = (void *)(unsigned long)packet +
 				sizeof(struct hv_netvsc_packet) +
 				    (num_pages * sizeof(struct hv_page_buffer));

 	/* If the rndis msg goes beyond 1 page, we will add 1 later */
 	packet->page_buf_cnt = num_pages - 1;

 	/* Initialize it from the skb */
 	packet->total_data_buflen = skb->len;

 	/* Start filling in the page buffers starting after RNDIS buffer. */
 	packet->page_buf[1].pfn = virt_to_phys(skb->data) >> PAGE_SHIFT;
 	packet->page_buf[1].offset
 		= (unsigned long)skb->data & (PAGE_SIZE - 1);
 	if (npg_data == 1)
 		packet->page_buf[1].len = skb_headlen(skb);
 	else
 		packet->page_buf[1].len = PAGE_SIZE
 			- packet->page_buf[1].offset;

 	for (i = 2; i <= npg_data; i++) {
 		packet->page_buf[i].pfn = virt_to_phys(skb->data
 			+ PAGE_SIZE * (i-1)) >> PAGE_SHIFT;
 		packet->page_buf[i].offset = 0;
 		packet->page_buf[i].len = PAGE_SIZE;
 	}
 	if (npg_data > 1)
 		packet->page_buf[npg_data].len = (((unsigned long)skb->data
 			+ skb_headlen(skb) - 1) & (PAGE_SIZE - 1)) + 1;

 	/* Additional fragments are after SKB data */
 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
 		const skb_frag_t *f = &skb_shinfo(skb)->frags[i];

 		packet->page_buf[i+npg_data+1].pfn =
 			page_to_pfn(skb_frag_page(f));
 		packet->page_buf[i+npg_data+1].offset = f->page_offset;
 		packet->page_buf[i+npg_data+1].len = skb_frag_size(f);
 	}

 	/* Set the completion routine */
 	packet->completion.send.send_completion = netvsc_xmit_completion;
 	packet->completion.send.send_completion_ctx = packet;
 	packet->completion.send.send_completion_tid = (unsigned long)skb;

 	ret = rndis_filter_send(net_device_ctx->device_ctx,
 				  packet);
 	if (ret == 0) {
 		net->stats.tx_bytes += skb->len;
 		net->stats.tx_packets++;
 	} else {
 		kfree(packet);
 		if (ret != -EAGAIN) {
 			dev_kfree_skb_any(skb);
 			net->stats.tx_dropped++;
 		}
 	}

 	return (ret == -EAGAIN) ? NETDEV_TX_BUSY : NETDEV_TX_OK;
 }

 /*
  * netvsc_linkstatus_callback - Link up/down notification
  */
 void netvsc_linkstatus_callback(struct hv_device *device_obj,
 				       unsigned int status)
 {
 	struct net_device *net;
 	struct net_device_context *ndev_ctx;
 	struct netvsc_device *net_device;

 	net_device = hv_get_drvdata(device_obj);
 	net = net_device->ndev;

 	if (!net) {
 		netdev_err(net, "got link status but net device "
 				"not initialized yet\n");
 		return;
 	}

 	if (status == 1) {
 		netif_carrier_on(net);
 		ndev_ctx = netdev_priv(net);
 		schedule_delayed_work(&ndev_ctx->dwork, 0);
 		schedule_delayed_work(&ndev_ctx->dwork, msecs_to_jiffies(20));
 	} else {
 		netif_carrier_off(net);
 	}
 }

 /*
  * netvsc_recv_callback -  Callback when we receive a packet from the
  * "wire" on the specified device.
  */
 int netvsc_recv_callback(struct hv_device *device_obj,
 				struct hv_netvsc_packet *packet)
 {
 	struct net_device *net;
 	struct sk_buff *skb;

 	net = ((struct netvsc_device *)hv_get_drvdata(device_obj))->ndev;
 	if (!net) {
 		netdev_err(net, "got receive callback but net device"
 			" not initialized yet\n");
 		packet->status = NVSP_STAT_FAIL;
 		return 0;
 	}

 	/* Allocate a skb - TODO direct I/O to pages? */
 	skb = netdev_alloc_skb_ip_align(net, packet->total_data_buflen);
 	if (unlikely(!skb)) {
 		++net->stats.rx_dropped;
 		packet->status = NVSP_STAT_FAIL;
 		return 0;
 	}

 	/*
 	 * Copy to skb. This copy is needed here since the memory pointed by
 	 * hv_netvsc_packet cannot be deallocated
 	 */
 	memcpy(skb_put(skb, packet->total_data_buflen), packet->data,
 		packet->total_data_buflen);

 	skb->protocol = eth_type_trans(skb, net);
 	skb->ip_summed = CHECKSUM_NONE;
 	if (packet->vlan_tci & VLAN_TAG_PRESENT)
 		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
 				       packet->vlan_tci);

 	net->stats.rx_packets++;
 	net->stats.rx_bytes += packet->total_data_buflen;

 	/*
 	 * Pass the skb back up. Network stack will deallocate the skb when it
 	 * is done.
 	 * TODO - use NAPI?
 	 */
 	netif_rx(skb);

 	return 0;
 }

 static void netvsc_get_drvinfo(struct net_device *net,
 			       struct ethtool_drvinfo *info)
 {
 	strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
 	strlcpy(info->version, HV_DRV_VERSION, sizeof(info->version));
 	strlcpy(info->fw_version, "N/A", sizeof(info->fw_version));
 }

 static int netvsc_change_mtu(struct net_device *ndev, int mtu)
 {
 	struct net_device_context *ndevctx = netdev_priv(ndev);
 	struct hv_device *hdev =  ndevctx->device_ctx;
 	struct netvsc_device *nvdev = hv_get_drvdata(hdev);
 	struct netvsc_device_info device_info;
 	int limit = ETH_DATA_LEN;

 	if (nvdev == NULL || nvdev->destroy)
 		return -ENODEV;

 	if (nvdev->nvsp_version == NVSP_PROTOCOL_VERSION_2)
 		limit = NETVSC_MTU;

 	if (mtu < 68 || mtu > limit)
 		return -EINVAL;

 	nvdev->start_remove = true;
 	cancel_delayed_work_sync(&ndevctx->dwork);
 	cancel_work_sync(&ndevctx->work);
 	netif_tx_disable(ndev);
 	rndis_filter_device_remove(hdev);

 	ndev->mtu = mtu;

 	ndevctx->device_ctx = hdev;
 	hv_set_drvdata(hdev, ndev);
 	device_info.ring_size = ring_size;
 	rndis_filter_device_add(hdev, &device_info);
 	netif_wake_queue(ndev);

 	return 0;
 }


 static int netvsc_set_mac_addr(struct net_device *ndev, void *p)
 {
 	struct net_device_context *ndevctx = netdev_priv(ndev);
 	struct hv_device *hdev =  ndevctx->device_ctx;
 	struct sockaddr *addr = p;
 	char save_adr[ETH_ALEN];
 	unsigned char save_aatype;
 	int err;

 	memcpy(save_adr, ndev->dev_addr, ETH_ALEN);
 	save_aatype = ndev->addr_assign_type;

 	err = eth_mac_addr(ndev, p);
 	if (err != 0)
 		return err;

 	err = rndis_filter_set_device_mac(hdev, addr->sa_data);
 	if (err != 0) {
 		/* roll back to saved MAC */
 		memcpy(ndev->dev_addr, save_adr, ETH_ALEN);
 		ndev->addr_assign_type = save_aatype;
 	}

 	return err;
 }


 static const struct ethtool_ops ethtool_ops = {
 	.get_drvinfo	= netvsc_get_drvinfo,
 	.get_link	= ethtool_op_get_link,
 };

 static const struct net_device_ops device_ops = {
 	.ndo_open =			netvsc_open,
 	.ndo_stop =			netvsc_close,
 	.ndo_start_xmit =		netvsc_start_xmit,
 	.ndo_set_rx_mode =		netvsc_set_multicast_list,
 	.ndo_change_mtu =		netvsc_change_mtu,
 	.ndo_validate_addr =		eth_validate_addr,
 	.ndo_set_mac_address =		netvsc_set_mac_addr,
 };

 /*
  * Send GARP packet to network peers after migrations.
  * After Quick Migration, the network is not immediately operational in the
  * current context when receiving RNDIS_STATUS_MEDIA_CONNECT event. So, add
  * another netif_notify_peers() into a delayed work, otherwise GARP packet
  * will not be sent after quick migration, and cause network disconnection.
  */
 static void netvsc_send_garp(struct work_struct *w)
 {
 	struct net_device_context *ndev_ctx;
 	struct net_device *net;
 	struct netvsc_device *net_device;

 	ndev_ctx = container_of(w, struct net_device_context, dwork.work);
 	net_device = hv_get_drvdata(ndev_ctx->device_ctx);
 	net = net_device->ndev;
 	netdev_notify_peers(net);
 }


 static int netvsc_probe(struct hv_device *dev,
 			const struct hv_vmbus_device_id *dev_id)
 {
 	struct net_device *net = NULL;
 	struct net_device_context *net_device_ctx;
 	struct netvsc_device_info device_info;
 	int ret;

 	net = alloc_etherdev(sizeof(struct net_device_context));
 	if (!net)
 		return -ENOMEM;

 	/* Set initial state */
 	netif_carrier_off(net);

 	net_device_ctx = netdev_priv(net);
 	net_device_ctx->device_ctx = dev;
 	hv_set_drvdata(dev, net);
 	INIT_DELAYED_WORK(&net_device_ctx->dwork, netvsc_send_garp);
 	INIT_WORK(&net_device_ctx->work, do_set_multicast);

 	net->netdev_ops = &device_ops;

 	/* TODO: Add GSO and Checksum offload */
 	net->hw_features = 0;
 	net->features = NETIF_F_HW_VLAN_CTAG_TX;

 	SET_ETHTOOL_OPS(net, &ethtool_ops);
 	SET_NETDEV_DEV(net, &dev->device);

 	ret = register_netdev(net);
 	if (ret != 0) {
 		pr_err("Unable to register netdev.\n");
 		free_netdev(net);
 		goto out;
 	}

 	/* Notify the netvsc driver of the new device */
 	device_info.ring_size = ring_size;
 	ret = rndis_filter_device_add(dev, &device_info);
 	if (ret != 0) {
 		netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);
 		unregister_netdev(net);
 		free_netdev(net);
 		hv_set_drvdata(dev, NULL);
 		return ret;
 	}
 	memcpy(net->dev_addr, device_info.mac_adr, ETH_ALEN);

 	netif_carrier_on(net);

 out:
 	return ret;
 }

 static int netvsc_remove(struct hv_device *dev)
 {
 	struct net_device *net;
 	struct net_device_context *ndev_ctx;
 	struct netvsc_device *net_device;

 	net_device = hv_get_drvdata(dev);
 	net = net_device->ndev;

 	if (net == NULL) {
 		dev_err(&dev->device, "No net device to remove\n");
 		return 0;
 	}

 	net_device->start_remove = true;

 	ndev_ctx = netdev_priv(net);
 	cancel_delayed_work_sync(&ndev_ctx->dwork);
 	cancel_work_sync(&ndev_ctx->work);

 	/* Stop outbound asap */
 	netif_tx_disable(net);

 	unregister_netdev(net);

 	/*
 	 * Call to the vsc driver to let it know that the device is being
 	 * removed
 	 */
 	rndis_filter_device_remove(dev);

 	free_netdev(net);
 	return 0;
 }

 static const struct hv_vmbus_device_id id_table[] = {
 	/* Network guid */
 	{ HV_NIC_GUID, },
 	{ },
 };

 MODULE_DEVICE_TABLE(vmbus, id_table);

 /* The one and only one */
 static struct  hv_driver netvsc_drv = {
 	.name = KBUILD_MODNAME,
 	.id_table = id_table,
 	.probe = netvsc_probe,
 	.remove = netvsc_remove,
 };

 static void __exit netvsc_drv_exit(void)
 {
 	vmbus_driver_unregister(&netvsc_drv);
 }

 static int __init netvsc_drv_init(void)
 {
 	if (ring_size < RING_SIZE_MIN) {
 		ring_size = RING_SIZE_MIN;
 		pr_info("Increased ring_size to %d (min allowed)\n",
 			ring_size);
 	}
 	return vmbus_driver_register(&netvsc_drv);
 }

 MODULE_LICENSE("GPL");
 MODULE_VERSION(HV_DRV_VERSION);
 MODULE_DESCRIPTION("Microsoft Hyper-V network driver");

 module_init(netvsc_drv_init);
 module_exit(netvsc_drv_exit);
	/*
	* Copyright (c) 2009, Microsoft Corporation.
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms and conditions of the GNU General Public License,
	* version 2, as published by the Free Software Foundation.
	*
	* This program is distributed in the hope it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	* more details.
	*
	* You should have received a copy of the GNU General Public License along with
	* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
	* Place - Suite 330, Boston, MA 02111-1307 USA.
	*
	* Authors:
	* Haiyang Zhang <haiyangz@microsoft.com>
	* Hank Janssen <hjanssen@microsoft.com>
	*/
	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/init.h>
	#include <linux/atomic.h>
	#include <linux/module.h>
	#include <linux/highmem.h>
	#include <linux/device.h>
	#include <linux/io.h>
	#include <linux/delay.h>
	#include <linux/netdevice.h>
	#include <linux/inetdevice.h>
	#include <linux/etherdevice.h>
	#include <linux/skbuff.h>
	#include <linux/if_vlan.h>
	#include <linux/in.h>
	#include <linux/slab.h>
	#include <net/arp.h>
	#include <net/route.h>
	#include <net/sock.h>
	#include <net/pkt_sched.h>

	#include "hyperv_net.h"

	struct net_device_context {
	/* point back to our device context */
	struct hv_device *device_ctx;
	struct delayed_work dwork;
	struct work_struct work;
	};

	#define RING_SIZE_MIN 64
	static int ring_size = 128;
	module_param(ring_size, int, S_IRUGO);
	MODULE_PARM_DESC(ring_size, "Ring buffer size (# of pages)");

	static void do_set_multicast(struct work_struct *w)
	{
	struct net_device_context *ndevctx =
	container_of(w, struct net_device_context, work);
	struct netvsc_device *nvdev;
	struct rndis_device *rdev;

	nvdev = hv_get_drvdata(ndevctx->device_ctx);
	if (nvdev == NULL \|\| nvdev->ndev == NULL)
	return;

	rdev = nvdev->extension;
	if (rdev == NULL)
	return;

	if (nvdev->ndev->flags & IFF_PROMISC)
	rndis_filter_set_packet_filter(rdev,
	NDIS_PACKET_TYPE_PROMISCUOUS);
	else
	rndis_filter_set_packet_filter(rdev,
	NDIS_PACKET_TYPE_BROADCAST \|
	NDIS_PACKET_TYPE_ALL_MULTICAST \|
	NDIS_PACKET_TYPE_DIRECTED);
	}

	static void netvsc_set_multicast_list(struct net_device *net)
	{
	struct net_device_context *net_device_ctx = netdev_priv(net);

	schedule_work(&net_device_ctx->work);
	}

	static int netvsc_open(struct net_device *net)
	{
	struct net_device_context *net_device_ctx = netdev_priv(net);
	struct hv_device *device_obj = net_device_ctx->device_ctx;
	int ret = 0;

	/* Open up the device */
	ret = rndis_filter_open(device_obj);
	if (ret != 0) {
	netdev_err(net, "unable to open device (ret %d).\n", ret);
	return ret;
	}

	netif_start_queue(net);

	return ret;
	}

	static int netvsc_close(struct net_device *net)
	{
	struct net_device_context *net_device_ctx = netdev_priv(net);
	struct hv_device *device_obj = net_device_ctx->device_ctx;
	int ret;

	netif_tx_disable(net);

	/* Make sure netvsc_set_multicast_list doesn't re-enable filter! */
	cancel_work_sync(&net_device_ctx->work);
	ret = rndis_filter_close(device_obj);
	if (ret != 0)
	netdev_err(net, "unable to close device (ret %d).\n", ret);

	return ret;
	}

	static void netvsc_xmit_completion(void *context)
	{
	struct hv_netvsc_packet packet = (struct hv_netvsc_packet )context;
	struct sk_buff skb = (struct sk_buff )
	(unsigned long)packet->completion.send.send_completion_tid;

	kfree(packet);

	if (skb)
	dev_kfree_skb_any(skb);
	}

	static int netvsc_start_xmit(struct sk_buff skb, struct net_device net)
	{
	struct net_device_context *net_device_ctx = netdev_priv(net);
	struct hv_netvsc_packet *packet;
	int ret;
	unsigned int i, num_pages, npg_data;

	/* Add multipages for skb->data and additional 2 for RNDIS */
	npg_data = (((unsigned long)skb->data + skb_headlen(skb) - 1)
	>> PAGE_SHIFT) - ((unsigned long)skb->data >> PAGE_SHIFT) + 1;
	num_pages = skb_shinfo(skb)->nr_frags + npg_data + 2;

	/* Allocate a netvsc packet based on # of frags. */
	packet = kzalloc(sizeof(struct hv_netvsc_packet) +
	(num_pages * sizeof(struct hv_page_buffer)) +
	sizeof(struct rndis_filter_packet) +
	NDIS_VLAN_PPI_SIZE, GFP_ATOMIC);
	if (!packet) {
	/* out of memory, drop packet */
	netdev_err(net, "unable to allocate hv_netvsc_packet\n");

	dev_kfree_skb(skb);
	net->stats.tx_dropped++;
	return NETDEV_TX_OK;
	}

	packet->vlan_tci = skb->vlan_tci;

	packet->extension = (void *)(unsigned long)packet +
	sizeof(struct hv_netvsc_packet) +
	(num_pages * sizeof(struct hv_page_buffer));

	/* If the rndis msg goes beyond 1 page, we will add 1 later */
	packet->page_buf_cnt = num_pages - 1;

	/* Initialize it from the skb */
	packet->total_data_buflen = skb->len;

	/* Start filling in the page buffers starting after RNDIS buffer. */
	packet->page_buf[1].pfn = virt_to_phys(skb->data) >> PAGE_SHIFT;
	packet->page_buf[1].offset
	= (unsigned long)skb->data & (PAGE_SIZE - 1);
	if (npg_data == 1)
	packet->page_buf[1].len = skb_headlen(skb);
	else
	packet->page_buf[1].len = PAGE_SIZE
	- packet->page_buf[1].offset;

	for (i = 2; i <= npg_data; i++) {
	packet->page_buf[i].pfn = virt_to_phys(skb->data
	+ PAGE_SIZE * (i-1)) >> PAGE_SHIFT;
	packet->page_buf[i].offset = 0;
	packet->page_buf[i].len = PAGE_SIZE;
	}
	if (npg_data > 1)
	packet->page_buf[npg_data].len = (((unsigned long)skb->data
	+ skb_headlen(skb) - 1) & (PAGE_SIZE - 1)) + 1;

	/* Additional fragments are after SKB data */
	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
	const skb_frag_t *f = &skb_shinfo(skb)->frags[i];

	packet->page_buf[i+npg_data+1].pfn =
	page_to_pfn(skb_frag_page(f));
	packet->page_buf[i+npg_data+1].offset = f->page_offset;
	packet->page_buf[i+npg_data+1].len = skb_frag_size(f);
	}

	/* Set the completion routine */
	packet->completion.send.send_completion = netvsc_xmit_completion;
	packet->completion.send.send_completion_ctx = packet;
	packet->completion.send.send_completion_tid = (unsigned long)skb;

	ret = rndis_filter_send(net_device_ctx->device_ctx,
	packet);
	if (ret == 0) {
	net->stats.tx_bytes += skb->len;
	net->stats.tx_packets++;
	} else {
	kfree(packet);
	if (ret != -EAGAIN) {
	dev_kfree_skb_any(skb);
	net->stats.tx_dropped++;
	}
	}

	return (ret == -EAGAIN) ? NETDEV_TX_BUSY : NETDEV_TX_OK;
	}

	/*
	* netvsc_linkstatus_callback - Link up/down notification
	*/
	void netvsc_linkstatus_callback(struct hv_device *device_obj,
	unsigned int status)
	{
	struct net_device *net;
	struct net_device_context *ndev_ctx;
	struct netvsc_device *net_device;

	net_device = hv_get_drvdata(device_obj);
	net = net_device->ndev;

	if (!net) {
	netdev_err(net, "got link status but net device "
	"not initialized yet\n");
	return;
	}

	if (status == 1) {
	netif_carrier_on(net);
	ndev_ctx = netdev_priv(net);
	schedule_delayed_work(&ndev_ctx->dwork, 0);
	schedule_delayed_work(&ndev_ctx->dwork, msecs_to_jiffies(20));
	} else {
	netif_carrier_off(net);
	}
	}

	/*
	* netvsc_recv_callback - Callback when we receive a packet from the
	* "wire" on the specified device.
	*/
	int netvsc_recv_callback(struct hv_device *device_obj,
	struct hv_netvsc_packet *packet)
	{
	struct net_device *net;
	struct sk_buff *skb;

	net = ((struct netvsc_device *)hv_get_drvdata(device_obj))->ndev;
	if (!net) {
	netdev_err(net, "got receive callback but net device"
	" not initialized yet\n");
	packet->status = NVSP_STAT_FAIL;
	return 0;
	}

	/* Allocate a skb - TODO direct I/O to pages? */
	skb = netdev_alloc_skb_ip_align(net, packet->total_data_buflen);
	if (unlikely(!skb)) {
	++net->stats.rx_dropped;
	packet->status = NVSP_STAT_FAIL;
	return 0;
	}

	/*
	* Copy to skb. This copy is needed here since the memory pointed by
	* hv_netvsc_packet cannot be deallocated
	*/
	memcpy(skb_put(skb, packet->total_data_buflen), packet->data,
	packet->total_data_buflen);

	skb->protocol = eth_type_trans(skb, net);
	skb->ip_summed = CHECKSUM_NONE;
	if (packet->vlan_tci & VLAN_TAG_PRESENT)
	__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
	packet->vlan_tci);

	net->stats.rx_packets++;
	net->stats.rx_bytes += packet->total_data_buflen;

	/*
	* Pass the skb back up. Network stack will deallocate the skb when it
	* is done.
	* TODO - use NAPI?
	*/
	netif_rx(skb);

	return 0;
	}

	static void netvsc_get_drvinfo(struct net_device *net,
	struct ethtool_drvinfo *info)
	{
	strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
	strlcpy(info->version, HV_DRV_VERSION, sizeof(info->version));
	strlcpy(info->fw_version, "N/A", sizeof(info->fw_version));
	}

	static int netvsc_change_mtu(struct net_device *ndev, int mtu)
	{
	struct net_device_context *ndevctx = netdev_priv(ndev);
	struct hv_device *hdev = ndevctx->device_ctx;
	struct netvsc_device *nvdev = hv_get_drvdata(hdev);
	struct netvsc_device_info device_info;
	int limit = ETH_DATA_LEN;

	if (nvdev == NULL \|\| nvdev->destroy)
	return -ENODEV;

	if (nvdev->nvsp_version == NVSP_PROTOCOL_VERSION_2)
	limit = NETVSC_MTU;

	if (mtu < 68 \|\| mtu > limit)
	return -EINVAL;

	nvdev->start_remove = true;
	cancel_delayed_work_sync(&ndevctx->dwork);
	cancel_work_sync(&ndevctx->work);
	netif_tx_disable(ndev);
	rndis_filter_device_remove(hdev);

	ndev->mtu = mtu;

	ndevctx->device_ctx = hdev;
	hv_set_drvdata(hdev, ndev);
	device_info.ring_size = ring_size;
	rndis_filter_device_add(hdev, &device_info);
	netif_wake_queue(ndev);

	return 0;
	}


	static int netvsc_set_mac_addr(struct net_device ndev, void p)
	{
	struct net_device_context *ndevctx = netdev_priv(ndev);
	struct hv_device *hdev = ndevctx->device_ctx;
	struct sockaddr *addr = p;
	char save_adr[ETH_ALEN];
	unsigned char save_aatype;
	int err;

	memcpy(save_adr, ndev->dev_addr, ETH_ALEN);
	save_aatype = ndev->addr_assign_type;

	err = eth_mac_addr(ndev, p);
	if (err != 0)
	return err;

	err = rndis_filter_set_device_mac(hdev, addr->sa_data);
	if (err != 0) {
	/* roll back to saved MAC */
	memcpy(ndev->dev_addr, save_adr, ETH_ALEN);
	ndev->addr_assign_type = save_aatype;
	}

	return err;
	}


	static const struct ethtool_ops ethtool_ops = {
	.get_drvinfo = netvsc_get_drvinfo,
	.get_link = ethtool_op_get_link,
	};

	static const struct net_device_ops device_ops = {
	.ndo_open = netvsc_open,
	.ndo_stop = netvsc_close,
	.ndo_start_xmit = netvsc_start_xmit,
	.ndo_set_rx_mode = netvsc_set_multicast_list,
	.ndo_change_mtu = netvsc_change_mtu,
	.ndo_validate_addr = eth_validate_addr,
	.ndo_set_mac_address = netvsc_set_mac_addr,
	};

	/*
	* Send GARP packet to network peers after migrations.
	* After Quick Migration, the network is not immediately operational in the
	* current context when receiving RNDIS_STATUS_MEDIA_CONNECT event. So, add
	* another netif_notify_peers() into a delayed work, otherwise GARP packet
	* will not be sent after quick migration, and cause network disconnection.
	*/
	static void netvsc_send_garp(struct work_struct *w)
	{
	struct net_device_context *ndev_ctx;
	struct net_device *net;
	struct netvsc_device *net_device;

	ndev_ctx = container_of(w, struct net_device_context, dwork.work);
	net_device = hv_get_drvdata(ndev_ctx->device_ctx);
	net = net_device->ndev;
	netdev_notify_peers(net);
	}


	static int netvsc_probe(struct hv_device *dev,
	const struct hv_vmbus_device_id *dev_id)
	{
	struct net_device *net = NULL;
	struct net_device_context *net_device_ctx;
	struct netvsc_device_info device_info;
	int ret;

	net = alloc_etherdev(sizeof(struct net_device_context));
	if (!net)
	return -ENOMEM;

	/* Set initial state */
	netif_carrier_off(net);

	net_device_ctx = netdev_priv(net);
	net_device_ctx->device_ctx = dev;
	hv_set_drvdata(dev, net);
	INIT_DELAYED_WORK(&net_device_ctx->dwork, netvsc_send_garp);
	INIT_WORK(&net_device_ctx->work, do_set_multicast);

	net->netdev_ops = &device_ops;

	/* TODO: Add GSO and Checksum offload */
	net->hw_features = 0;
	net->features = NETIF_F_HW_VLAN_CTAG_TX;

	SET_ETHTOOL_OPS(net, &ethtool_ops);
	SET_NETDEV_DEV(net, &dev->device);

	ret = register_netdev(net);
	if (ret != 0) {
	pr_err("Unable to register netdev.\n");
	free_netdev(net);
	goto out;
	}

	/* Notify the netvsc driver of the new device */
	device_info.ring_size = ring_size;
	ret = rndis_filter_device_add(dev, &device_info);
	if (ret != 0) {
	netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);
	unregister_netdev(net);
	free_netdev(net);
	hv_set_drvdata(dev, NULL);
	return ret;
	}
	memcpy(net->dev_addr, device_info.mac_adr, ETH_ALEN);

	netif_carrier_on(net);

	out:
	return ret;
	}

	static int netvsc_remove(struct hv_device *dev)
	{
	struct net_device *net;
	struct net_device_context *ndev_ctx;
	struct netvsc_device *net_device;

	net_device = hv_get_drvdata(dev);
	net = net_device->ndev;

	if (net == NULL) {
	dev_err(&dev->device, "No net device to remove\n");
	return 0;
	}

	net_device->start_remove = true;

	ndev_ctx = netdev_priv(net);
	cancel_delayed_work_sync(&ndev_ctx->dwork);
	cancel_work_sync(&ndev_ctx->work);

	/* Stop outbound asap */
	netif_tx_disable(net);

	unregister_netdev(net);

	/*
	* Call to the vsc driver to let it know that the device is being
	* removed
	*/
	rndis_filter_device_remove(dev);

	free_netdev(net);
	return 0;
	}

	static const struct hv_vmbus_device_id id_table[] = {
	/* Network guid */
	{ HV_NIC_GUID, },
	{ },
	};

	MODULE_DEVICE_TABLE(vmbus, id_table);

	/* The one and only one */
	static struct hv_driver netvsc_drv = {
	.name = KBUILD_MODNAME,
	.id_table = id_table,
	.probe = netvsc_probe,
	.remove = netvsc_remove,
	};

	static void __exit netvsc_drv_exit(void)
	{
	vmbus_driver_unregister(&netvsc_drv);
	}

	static int __init netvsc_drv_init(void)
	{
	if (ring_size < RING_SIZE_MIN) {
	ring_size = RING_SIZE_MIN;
	pr_info("Increased ring_size to %d (min allowed)\n",
	ring_size);
	}
	return vmbus_driver_register(&netvsc_drv);
	}

	MODULE_LICENSE("GPL");
	MODULE_VERSION(HV_DRV_VERSION);
	MODULE_DESCRIPTION("Microsoft Hyper-V network driver");

	module_init(netvsc_drv_init);
	module_exit(netvsc_drv_exit);