text: // SPDX-License-Identifier: GPL-2.0-only
  /*
   * Copyright (c) 2009, Microsoft Corporation.
   *
   * 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/pci.h>
  #include <linux/skbuff.h>
  #include <linux/if_vlan.h>
  #include <linux/in.h>
  #include <linux/slab.h>
  #include <linux/rtnetlink.h>
  #include <linux/netpoll.h>
  
  #include <net/arp.h>
  #include <net/route.h>
  #include <net/sock.h>
  #include <net/pkt_sched.h>
  #include <net/checksum.h>
  #include <net/ip6_checksum.h>
  
  #include "hyperv_net.h"
  
  #define RING_SIZE_MIN	64
  #define RETRY_US_LO	5000
  #define RETRY_US_HI	10000
  #define RETRY_MAX	2000	/* >10 sec */
  
  #define LINKCHANGE_INT (2 * HZ)
  #define VF_TAKEOVER_INT (HZ / 10)
  
  static unsigned int ring_size __ro_after_init = 128;
  module_param(ring_size, uint, 0444);
  MODULE_PARM_DESC(ring_size, "Ring buffer size (# of pages)");
  unsigned int netvsc_ring_bytes __ro_after_init;
  
  static const u32 default_msg = NETIF_MSG_DRV | NETIF_MSG_PROBE |
  				NETIF_MSG_LINK | NETIF_MSG_IFUP |
  				NETIF_MSG_IFDOWN | NETIF_MSG_RX_ERR |
  				NETIF_MSG_TX_ERR;
  
  static int debug = -1;
  module_param(debug, int, 0444);
  MODULE_PARM_DESC(debug, "Debug level (0=none,...,16=all)");
  
  static LIST_HEAD(netvsc_dev_list);
  
  static void netvsc_change_rx_flags(struct net_device *net, int change)
  {
  	struct net_device_context *ndev_ctx = netdev_priv(net);
  	struct net_device *vf_netdev = rtnl_dereference(ndev_ctx->vf_netdev);
  	int inc;
  
  	if (!vf_netdev)
  		return;
  
  	if (change & IFF_PROMISC) {
  		inc = (net->flags & IFF_PROMISC) ? 1 : -1;
  		dev_set_promiscuity(vf_netdev, inc);
  	}
  
  	if (change & IFF_ALLMULTI) {
  		inc = (net->flags & IFF_ALLMULTI) ? 1 : -1;
  		dev_set_allmulti(vf_netdev, inc);
  	}
  }
  
  static void netvsc_set_rx_mode(struct net_device *net)
  {
  	struct net_device_context *ndev_ctx = netdev_priv(net);
  	struct net_device *vf_netdev;
  	struct netvsc_device *nvdev;
  
  	rcu_read_lock();
  	vf_netdev = rcu_dereference(ndev_ctx->vf_netdev);
  	if (vf_netdev) {
  		dev_uc_sync(vf_netdev, net);
  		dev_mc_sync(vf_netdev, net);
  	}
  
  	nvdev = rcu_dereference(ndev_ctx->nvdev);
  	if (nvdev)
  		rndis_filter_update(nvdev);
  	rcu_read_unlock();
  }
  
  static void netvsc_tx_enable(struct netvsc_device *nvscdev,
  			     struct net_device *ndev)
  {
  	nvscdev->tx_disable = false;
  	virt_wmb(); /* ensure queue wake up mechanism is on */
  
  	netif_tx_wake_all_queues(ndev);
  }
  
  static int netvsc_open(struct net_device *net)
  {
  	struct net_device_context *ndev_ctx = netdev_priv(net);
  	struct net_device *vf_netdev = rtnl_dereference(ndev_ctx->vf_netdev);
  	struct netvsc_device *nvdev = rtnl_dereference(ndev_ctx->nvdev);
  	struct rndis_device *rdev;
  	int ret = 0;
  
  	netif_carrier_off(net);
  
  	/* Open up the device */
  	ret = rndis_filter_open(nvdev);
  	if (ret != 0) {
  		netdev_err(net, "unable to open device (ret %d).\n", ret);
  		return ret;
  	}
  
  	rdev = nvdev->extension;
  	if (!rdev->link_state) {
  		netif_carrier_on(net);
  		netvsc_tx_enable(nvdev, net);
  	}
  
  	if (vf_netdev) {
  		/* Setting synthetic device up transparently sets
  		 * slave as up. If open fails, then slave will be
  		 * still be offline (and not used).
  		 */
  		ret = dev_open(vf_netdev, NULL);
  		if (ret)
  			netdev_warn(net,
  				    "unable to open slave: %s: %d\n",
  				    vf_netdev->name, ret);
  	}
  	return 0;
  }
  
  static int netvsc_wait_until_empty(struct netvsc_device *nvdev)
  {
  	unsigned int retry = 0;
  	int i;
  
  	/* Ensure pending bytes in ring are read */
  	for (;;) {
  		u32 aread = 0;
  
  		for (i = 0; i < nvdev->num_chn; i++) {
  			struct vmbus_channel *chn
  				= nvdev->chan_table[i].channel;
  
  			if (!chn)
  				continue;
  
  			/* make sure receive not running now */
  			napi_synchronize(&nvdev->chan_table[i].napi);
  
  			aread = hv_get_bytes_to_read(&chn->inbound);
  			if (aread)
  				break;
  
  			aread = hv_get_bytes_to_read(&chn->outbound);
  			if (aread)
  				break;
  		}
  
  		if (aread == 0)
  			return 0;
  
  		if (++retry > RETRY_MAX)
  			return -ETIMEDOUT;
  
  		usleep_range(RETRY_US_LO, RETRY_US_HI);
  	}
  }
  
  static void netvsc_tx_disable(struct netvsc_device *nvscdev,
  			      struct net_device *ndev)
  {
  	if (nvscdev) {
  		nvscdev->tx_disable = true;
  		virt_wmb(); /* ensure txq will not wake up after stop */
  	}
  
  	netif_tx_disable(ndev);
  }
  
  static int netvsc_close(struct net_device *net)
  {
  	struct net_device_context *net_device_ctx = netdev_priv(net);
  	struct net_device *vf_netdev
  		= rtnl_dereference(net_device_ctx->vf_netdev);
  	struct netvsc_device *nvdev = rtnl_dereference(net_device_ctx->nvdev);
  	int ret;
  
  	netvsc_tx_disable(nvdev, net);
  
  	/* No need to close rndis filter if it is removed already */
  	if (!nvdev)
  		return 0;
  
  	ret = rndis_filter_close(nvdev);
  	if (ret != 0) {
  		netdev_err(net, "unable to close device (ret %d).\n", ret);
  		return ret;
  	}
  
  	ret = netvsc_wait_until_empty(nvdev);
  	if (ret)
  		netdev_err(net, "Ring buffer not empty after closing rndis\n");
  
  	if (vf_netdev)
  		dev_close(vf_netdev);
  
  	return ret;
  }
  
  static inline void *init_ppi_data(struct rndis_message *msg,
  				  u32 ppi_size, u32 pkt_type)
  {
  	struct rndis_packet *rndis_pkt = &msg->msg.pkt;
  	struct rndis_per_packet_info *ppi;
  
  	rndis_pkt->data_offset += ppi_size;
  	ppi = (void *)rndis_pkt + rndis_pkt->per_pkt_info_offset
  		+ rndis_pkt->per_pkt_info_len;
  
  	ppi->size = ppi_size;
  	ppi->type = pkt_type;
  	ppi->internal = 0;
  	ppi->ppi_offset = sizeof(struct rndis_per_packet_info);
  
  	rndis_pkt->per_pkt_info_len += ppi_size;
  
  	return ppi + 1;
  }
  
  /* Azure hosts don't support non-TCP port numbers in hashing for fragmented
   * packets. We can use ethtool to change UDP hash level when necessary.
   */
  static inline u32 netvsc_get_hash(
  	struct sk_buff *skb,
  	const struct net_device_context *ndc)
  {
  	struct flow_keys flow;
  	u32 hash, pkt_proto = 0;
  	static u32 hashrnd __read_mostly;
  
  	net_get_random_once(&hashrnd, sizeof(hashrnd));
  
  	if (!skb_flow_dissect_flow_keys(skb, &flow, 0))
  		return 0;
  
  	switch (flow.basic.ip_proto) {
  	case IPPROTO_TCP:
  		if (flow.basic.n_proto == htons(ETH_P_IP))
  			pkt_proto = HV_TCP4_L4HASH;
  		else if (flow.basic.n_proto == htons(ETH_P_IPV6))
  			pkt_proto = HV_TCP6_L4HASH;
  
  		break;
  
  	case IPPROTO_UDP:
  		if (flow.basic.n_proto == htons(ETH_P_IP))
  			pkt_proto = HV_UDP4_L4HASH;
  		else if (flow.basic.n_proto == htons(ETH_P_IPV6))
  			pkt_proto = HV_UDP6_L4HASH;
  
  		break;
  	}
  
  	if (pkt_proto & ndc->l4_hash) {
  		return skb_get_hash(skb);
  	} else {
  		if (flow.basic.n_proto == htons(ETH_P_IP))
  			hash = jhash2((u32 *)&flow.addrs.v4addrs, 2, hashrnd);
  		else if (flow.basic.n_proto == htons(ETH_P_IPV6))
  			hash = jhash2((u32 *)&flow.addrs.v6addrs, 8, hashrnd);
  		else
  			hash = 0;
  
  		skb_set_hash(skb, hash, PKT_HASH_TYPE_L3);
  	}
  
  	return hash;
  }
  
  static inline int netvsc_get_tx_queue(struct net_device *ndev,
  				      struct sk_buff *skb, int old_idx)
  {
  	const struct net_device_context *ndc = netdev_priv(ndev);
  	struct sock *sk = skb->sk;
  	int q_idx;
  
  	q_idx = ndc->tx_table[netvsc_get_hash(skb, ndc) &
  			      (VRSS_SEND_TAB_SIZE - 1)];
  
  	/* If queue index changed record the new value */
  	if (q_idx != old_idx &&
  	    sk && sk_fullsock(sk) && rcu_access_pointer(sk->sk_dst_cache))
  		sk_tx_queue_set(sk, q_idx);
  
  	return q_idx;
  }
  
  /*
   * Select queue for transmit.
   *
   * If a valid queue has already been assigned, then use that.
   * Otherwise compute tx queue based on hash and the send table.
   *
   * This is basically similar to default (netdev_pick_tx) with the added step
   * of using the host send_table when no other queue has been assigned.
   *
   * TODO support XPS - but get_xps_queue not exported
   */
  static u16 netvsc_pick_tx(struct net_device *ndev, struct sk_buff *skb)
  {
  	int q_idx = sk_tx_queue_get(skb->sk);
  
  	if (q_idx < 0 || skb->ooo_okay || q_idx >= ndev->real_num_tx_queues) {
  		/* If forwarding a packet, we use the recorded queue when
  		 * available for better cache locality.
  		 */
  		if (skb_rx_queue_recorded(skb))
  			q_idx = skb_get_rx_queue(skb);
  		else
  			q_idx = netvsc_get_tx_queue(ndev, skb, q_idx);
  	}
  
  	return q_idx;
  }
  
  static u16 netvsc_select_queue(struct net_device *ndev, struct sk_buff *skb,
  			       struct net_device *sb_dev)
  {
  	struct net_device_context *ndc = netdev_priv(ndev);
  	struct net_device *vf_netdev;
  	u16 txq;
  
  	rcu_read_lock();
  	vf_netdev = rcu_dereference(ndc->vf_netdev);
  	if (vf_netdev) {
  		const struct net_device_ops *vf_ops = vf_netdev->netdev_ops;
  
  		if (vf_ops->ndo_select_queue)
  			txq = vf_ops->ndo_select_queue(vf_netdev, skb, sb_dev);
  		else
  			txq = netdev_pick_tx(vf_netdev, skb, NULL);
  
  		/* Record the queue selected by VF so that it can be
  		 * used for common case where VF has more queues than
  		 * the synthetic device.
  		 */
  		qdisc_skb_cb(skb)->slave_dev_queue_mapping = txq;
  	} else {
  		txq = netvsc_pick_tx(ndev, skb);
  	}
  	rcu_read_unlock();
  
  	while (unlikely(txq >= ndev->real_num_tx_queues))
  		txq -= ndev->real_num_tx_queues;
  
  	return txq;
  }
  
  static u32 fill_pg_buf(struct page *page, u32 offset, u32 len,
  		       struct hv_page_buffer *pb)
  {
  	int j = 0;
  
  	/* Deal with compound pages by ignoring unused part
  	 * of the page.
  	 */
  	page += (offset >> PAGE_SHIFT);
  	offset &= ~PAGE_MASK;
  
  	while (len > 0) {
  		unsigned long bytes;
  
  		bytes = PAGE_SIZE - offset;
  		if (bytes > len)
  			bytes = len;
  		pb[j].pfn = page_to_pfn(page);
  		pb[j].offset = offset;
  		pb[j].len = bytes;
  
  		offset += bytes;
  		len -= bytes;
  
  		if (offset == PAGE_SIZE && len) {
  			page++;
  			offset = 0;
  			j++;
  		}
  	}
  
  	return j + 1;
  }
  
  static u32 init_page_array(void *hdr, u32 len, struct sk_buff *skb,
  			   struct hv_netvsc_packet *packet,
  			   struct hv_page_buffer *pb)
  {
  	u32 slots_used = 0;
  	char *data = skb->data;
  	int frags = skb_shinfo(skb)->nr_frags;
  	int i;
  
  	/* The packet is laid out thus:
  	 * 1. hdr: RNDIS header and PPI
  	 * 2. skb linear data
  	 * 3. skb fragment data
  	 */
  	slots_used += fill_pg_buf(virt_to_page(hdr),
  				  offset_in_page(hdr),
  				  len, &pb[slots_used]);
  
  	packet->rmsg_size = len;
  	packet->rmsg_pgcnt = slots_used;
  
  	slots_used += fill_pg_buf(virt_to_page(data),
  				offset_in_page(data),
  				skb_headlen(skb), &pb[slots_used]);
  
  	for (i = 0; i < frags; i++) {
  		skb_frag_t *frag = skb_shinfo(skb)->frags + i;
  
  		slots_used += fill_pg_buf(skb_frag_page(frag),
  					frag->page_offset,
  					skb_frag_size(frag), &pb[slots_used]);
  	}
  	return slots_used;
  }
  
  static int count_skb_frag_slots(struct sk_buff *skb)
  {
  	int i, frags = skb_shinfo(skb)->nr_frags;
  	int pages = 0;
  
  	for (i = 0; i < frags; i++) {
  		skb_frag_t *frag = skb_shinfo(skb)->frags + i;
  		unsigned long size = skb_frag_size(frag);
  		unsigned long offset = frag->page_offset;
  
  		/* Skip unused frames from start of page */
  		offset &= ~PAGE_MASK;
  		pages += PFN_UP(offset + size);
  	}
  	return pages;
  }
  
  static int netvsc_get_slots(struct sk_buff *skb)
  {
  	char *data = skb->data;
  	unsigned int offset = offset_in_page(data);
  	unsigned int len = skb_headlen(skb);
  	int slots;
  	int frag_slots;
  
  	slots = DIV_ROUND_UP(offset + len, PAGE_SIZE);
  	frag_slots = count_skb_frag_slots(skb);
  	return slots + frag_slots;
  }
  
  static u32 net_checksum_info(struct sk_buff *skb)
  {
  	if (skb->protocol == htons(ETH_P_IP)) {
  		struct iphdr *ip = ip_hdr(skb);
  
  		if (ip->protocol == IPPROTO_TCP)
  			return TRANSPORT_INFO_IPV4_TCP;
  		else if (ip->protocol == IPPROTO_UDP)
  			return TRANSPORT_INFO_IPV4_UDP;
  	} else {
  		struct ipv6hdr *ip6 = ipv6_hdr(skb);
  
  		if (ip6->nexthdr == IPPROTO_TCP)
  			return TRANSPORT_INFO_IPV6_TCP;
  		else if (ip6->nexthdr == IPPROTO_UDP)
  			return TRANSPORT_INFO_IPV6_UDP;
  	}
  
  	return TRANSPORT_INFO_NOT_IP;
  }
  
  /* Send skb on the slave VF device. */
  static int netvsc_vf_xmit(struct net_device *net, struct net_device *vf_netdev,
  			  struct sk_buff *skb)
  {
  	struct net_device_context *ndev_ctx = netdev_priv(net);
  	unsigned int len = skb->len;
  	int rc;
  
  	skb->dev = vf_netdev;
  	skb->queue_mapping = qdisc_skb_cb(skb)->slave_dev_queue_mapping;
  
  	rc = dev_queue_xmit(skb);
  	if (likely(rc == NET_XMIT_SUCCESS || rc == NET_XMIT_CN)) {
  		struct netvsc_vf_pcpu_stats *pcpu_stats
  			= this_cpu_ptr(ndev_ctx->vf_stats);
  
  		u64_stats_update_begin(&pcpu_stats->syncp);
  		pcpu_stats->tx_packets++;
  		pcpu_stats->tx_bytes += len;
  		u64_stats_update_end(&pcpu_stats->syncp);
  	} else {
  		this_cpu_inc(ndev_ctx->vf_stats->tx_dropped);
  	}
  
  	return rc;
  }
  
  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 = NULL;
  	int ret;
  	unsigned int num_data_pgs;
  	struct rndis_message *rndis_msg;
  	struct net_device *vf_netdev;
  	u32 rndis_msg_size;
  	u32 hash;
  	struct hv_page_buffer pb[MAX_PAGE_BUFFER_COUNT];
  
  	/* if VF is present and up then redirect packets
  	 * already called with rcu_read_lock_bh
  	 */
  	vf_netdev = rcu_dereference_bh(net_device_ctx->vf_netdev);
  	if (vf_netdev && netif_running(vf_netdev) &&
  	    !netpoll_tx_running(net))
  		return netvsc_vf_xmit(net, vf_netdev, skb);
  
  	/* We will atmost need two pages to describe the rndis
  	 * header. We can only transmit MAX_PAGE_BUFFER_COUNT number
  	 * of pages in a single packet. If skb is scattered around
  	 * more pages we try linearizing it.
  	 */
  
  	num_data_pgs = netvsc_get_slots(skb) + 2;
  
  	if (unlikely(num_data_pgs > MAX_PAGE_BUFFER_COUNT)) {
  		++net_device_ctx->eth_stats.tx_scattered;
  
  		if (skb_linearize(skb))
  			goto no_memory;
  
  		num_data_pgs = netvsc_get_slots(skb) + 2;
  		if (num_data_pgs > MAX_PAGE_BUFFER_COUNT) {
  			++net_device_ctx->eth_stats.tx_too_big;
  			goto drop;
  		}
  	}
  
  	/*
  	 * Place the rndis header in the skb head room and
  	 * the skb->cb will be used for hv_netvsc_packet
  	 * structure.
  	 */
  	ret = skb_cow_head(skb, RNDIS_AND_PPI_SIZE);
  	if (ret)
  		goto no_memory;
  
  	/* Use the skb control buffer for building up the packet */
  	BUILD_BUG_ON(sizeof(struct hv_netvsc_packet) >
  			FIELD_SIZEOF(struct sk_buff, cb));
  	packet = (struct hv_netvsc_packet *)skb->cb;
  
  	packet->q_idx = skb_get_queue_mapping(skb);
  
  	packet->total_data_buflen = skb->len;
  	packet->total_bytes = skb->len;
  	packet->total_packets = 1;
  
  	rndis_msg = (struct rndis_message *)skb->head;
  
  	/* Add the rndis header */
  	rndis_msg->ndis_msg_type = RNDIS_MSG_PACKET;
  	rndis_msg->msg_len = packet->total_data_buflen;
  
  	rndis_msg->msg.pkt = (struct rndis_packet) {
  		.data_offset = sizeof(struct rndis_packet),
  		.data_len = packet->total_data_buflen,
  		.per_pkt_info_offset = sizeof(struct rndis_packet),
  	};
  
  	rndis_msg_size = RNDIS_MESSAGE_SIZE(struct rndis_packet);
  
  	hash = skb_get_hash_raw(skb);
  	if (hash != 0 && net->real_num_tx_queues > 1) {
  		u32 *hash_info;
  
  		rndis_msg_size += NDIS_HASH_PPI_SIZE;
  		hash_info = init_ppi_data(rndis_msg, NDIS_HASH_PPI_SIZE,
  					  NBL_HASH_VALUE);
  		*hash_info = hash;
  	}
  
  	if (skb_vlan_tag_present(skb)) {
  		struct ndis_pkt_8021q_info *vlan;
  
  		rndis_msg_size += NDIS_VLAN_PPI_SIZE;
  		vlan = init_ppi_data(rndis_msg, NDIS_VLAN_PPI_SIZE,
  				     IEEE_8021Q_INFO);
  
  		vlan->value = 0;
  		vlan->vlanid = skb_vlan_tag_get_id(skb);
  		vlan->cfi = skb_vlan_tag_get_cfi(skb);
  		vlan->pri = skb_vlan_tag_get_prio(skb);
  	}
  
  	if (skb_is_gso(skb)) {
  		struct ndis_tcp_lso_info *lso_info;
  
  		rndis_msg_size += NDIS_LSO_PPI_SIZE;
  		lso_info = init_ppi_data(rndis_msg, NDIS_LSO_PPI_SIZE,
  					 TCP_LARGESEND_PKTINFO);
  
  		lso_info->value = 0;
  		lso_info->lso_v2_transmit.type = NDIS_TCP_LARGE_SEND_OFFLOAD_V2_TYPE;
  		if (skb->protocol == htons(ETH_P_IP)) {
  			lso_info->lso_v2_transmit.ip_version =
  				NDIS_TCP_LARGE_SEND_OFFLOAD_IPV4;
  			ip_hdr(skb)->tot_len = 0;
  			ip_hdr(skb)->check = 0;
  			tcp_hdr(skb)->check =
  				~csum_tcpudp_magic(ip_hdr(skb)->saddr,
  						   ip_hdr(skb)->daddr, 0, IPPROTO_TCP, 0);
  		} else {
  			lso_info->lso_v2_transmit.ip_version =
  				NDIS_TCP_LARGE_SEND_OFFLOAD_IPV6;
  			ipv6_hdr(skb)->payload_len = 0;
  			tcp_hdr(skb)->check =
  				~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
  						 &ipv6_hdr(skb)->daddr, 0, IPPROTO_TCP, 0);
  		}
  		lso_info->lso_v2_transmit.tcp_header_offset = skb_transport_offset(skb);
  		lso_info->lso_v2_transmit.mss = skb_shinfo(skb)->gso_size;
  	} else if (skb->ip_summed == CHECKSUM_PARTIAL) {
  		if (net_checksum_info(skb) & net_device_ctx->tx_checksum_mask) {
  			struct ndis_tcp_ip_checksum_info *csum_info;
  
  			rndis_msg_size += NDIS_CSUM_PPI_SIZE;
  			csum_info = init_ppi_data(rndis_msg, NDIS_CSUM_PPI_SIZE,
  						  TCPIP_CHKSUM_PKTINFO);
  
  			csum_info->value = 0;
  			csum_info->transmit.tcp_header_offset = skb_transport_offset(skb);
  
  			if (skb->protocol == htons(ETH_P_IP)) {
  				csum_info->transmit.is_ipv4 = 1;
  
  				if (ip_hdr(skb)->protocol == IPPROTO_TCP)
  					csum_info->transmit.tcp_checksum = 1;
  				else
  					csum_info->transmit.udp_checksum = 1;
  			} else {
  				csum_info->transmit.is_ipv6 = 1;
  
  				if (ipv6_hdr(skb)->nexthdr == IPPROTO_TCP)
  					csum_info->transmit.tcp_checksum = 1;
  				else
  					csum_info->transmit.udp_checksum = 1;
  			}
  		} else {
  			/* Can't do offload of this type of checksum */
  			if (skb_checksum_help(skb))
  				goto drop;
  		}
  	}
  
  	/* Start filling in the page buffers with the rndis hdr */
  	rndis_msg->msg_len += rndis_msg_size;
  	packet->total_data_buflen = rndis_msg->msg_len;
  	packet->page_buf_cnt = init_page_array(rndis_msg, rndis_msg_size,
  					       skb, packet, pb);
  
  	/* timestamp packet in software */
  	skb_tx_timestamp(skb);
  
  	ret = netvsc_send(net, packet, rndis_msg, pb, skb);
  	if (likely(ret == 0))
  		return NETDEV_TX_OK;
  
  	if (ret == -EAGAIN) {
  		++net_device_ctx->eth_stats.tx_busy;
  		return NETDEV_TX_BUSY;
  	}
  
  	if (ret == -ENOSPC)
  		++net_device_ctx->eth_stats.tx_no_space;
  
  drop:
  	dev_kfree_skb_any(skb);
  	net->stats.tx_dropped++;
  
  	return NETDEV_TX_OK;
  
  no_memory:
  	++net_device_ctx->eth_stats.tx_no_memory;
  	goto drop;
  }
  
  /*
   * netvsc_linkstatus_callback - Link up/down notification
   */
  void netvsc_linkstatus_callback(struct net_device *net,
  				struct rndis_message *resp)
  {
  	struct rndis_indicate_status *indicate = &resp->msg.indicate_status;
  	struct net_device_context *ndev_ctx = netdev_priv(net);
  	struct netvsc_reconfig *event;
  	unsigned long flags;
  
  	/* Update the physical link speed when changing to another vSwitch */
  	if (indicate->status == RNDIS_STATUS_LINK_SPEED_CHANGE) {
  		u32 speed;
  
  		speed = *(u32 *)((void *)indicate
  				 + indicate->status_buf_offset) / 10000;
  		ndev_ctx->speed = speed;
  		return;
  	}
  
  	/* Handle these link change statuses below */
  	if (indicate->status != RNDIS_STATUS_NETWORK_CHANGE &&
  	    indicate->status != RNDIS_STATUS_MEDIA_CONNECT &&
  	    indicate->status != RNDIS_STATUS_MEDIA_DISCONNECT)
  		return;
  
  	if (net->reg_state != NETREG_REGISTERED)
  		return;
  
  	event = kzalloc(sizeof(*event), GFP_ATOMIC);
  	if (!event)
  		return;
  	event->event = indicate->status;
  
  	spin_lock_irqsave(&ndev_ctx->lock, flags);
  	list_add_tail(&event->list, &ndev_ctx->reconfig_events);
  	spin_unlock_irqrestore(&ndev_ctx->lock, flags);
  
  	schedule_delayed_work(&ndev_ctx->dwork, 0);
  }
  
  static void netvsc_comp_ipcsum(struct sk_buff *skb)
  {
  	struct iphdr *iph = (struct iphdr *)skb->data;
  
  	iph->check = 0;
  	iph->check = ip_fast_csum(iph, iph->ihl);
  }
  
  static struct sk_buff *netvsc_alloc_recv_skb(struct net_device *net,
  					     struct netvsc_channel *nvchan)
  {
  	struct napi_struct *napi = &nvchan->napi;
  	const struct ndis_pkt_8021q_info *vlan = nvchan->rsc.vlan;
  	const struct ndis_tcp_ip_checksum_info *csum_info =
  						nvchan->rsc.csum_info;
  	struct sk_buff *skb;
  	int i;
  
  	skb = napi_alloc_skb(napi, nvchan->rsc.pktlen);
  	if (!skb)
  		return skb;
  
  	/*
  	 * Copy to skb. This copy is needed here since the memory pointed by
  	 * hv_netvsc_packet cannot be deallocated
  	 */
  	for (i = 0; i < nvchan->rsc.cnt; i++)
  		skb_put_data(skb, nvchan->rsc.data[i], nvchan->rsc.len[i]);
  
  	skb->protocol = eth_type_trans(skb, net);
  
  	/* skb is already created with CHECKSUM_NONE */
  	skb_checksum_none_assert(skb);
  
  	/* Incoming packets may have IP header checksum verified by the host.
  	 * They may not have IP header checksum computed after coalescing.
  	 * We compute it here if the flags are set, because on Linux, the IP
  	 * checksum is always checked.
  	 */
  	if (csum_info && csum_info->receive.ip_checksum_value_invalid &&
  	    csum_info->receive.ip_checksum_succeeded &&
  	    skb->protocol == htons(ETH_P_IP))
  		netvsc_comp_ipcsum(skb);
  
  	/* Do L4 checksum offload if enabled and present.
  	 */
  	if (csum_info && (net->features & NETIF_F_RXCSUM)) {
  		if (csum_info->receive.tcp_checksum_succeeded ||
  		    csum_info->receive.udp_checksum_succeeded)
  			skb->ip_summed = CHECKSUM_UNNECESSARY;
  	}
  
  	if (vlan) {
  		u16 vlan_tci = vlan->vlanid | (vlan->pri << VLAN_PRIO_SHIFT) |
  			(vlan->cfi ? VLAN_CFI_MASK : 0);
  
  		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
  				       vlan_tci);
  	}
  
  	return skb;
  }
  
  /*
   * netvsc_recv_callback -  Callback when we receive a packet from the
   * "wire" on the specified device.
   */
  int netvsc_recv_callback(struct net_device *net,
  			 struct netvsc_device *net_device,
  			 struct netvsc_channel *nvchan)
  {
  	struct net_device_context *net_device_ctx = netdev_priv(net);
  	struct vmbus_channel *channel = nvchan->channel;
  	u16 q_idx = channel->offermsg.offer.sub_channel_index;
  	struct sk_buff *skb;
  	struct netvsc_stats *rx_stats;
  
  	if (net->reg_state != NETREG_REGISTERED)
  		return NVSP_STAT_FAIL;
  
  	/* Allocate a skb - TODO direct I/O to pages? */
  	skb = netvsc_alloc_recv_skb(net, nvchan);
  
  	if (unlikely(!skb)) {
  		++net_device_ctx->eth_stats.rx_no_memory;
  		return NVSP_STAT_FAIL;
  	}
  
  	skb_record_rx_queue(skb, q_idx);
  
  	/*
  	 * Even if injecting the packet, record the statistics
  	 * on the synthetic device because modifying the VF device
  	 * statistics will not work correctly.
  	 */
  	rx_stats = &nvchan->rx_stats;
  	u64_stats_update_begin(&rx_stats->syncp);
  	rx_stats->packets++;
  	rx_stats->bytes += nvchan->rsc.pktlen;
  
  	if (skb->pkt_type == PACKET_BROADCAST)
  		++rx_stats->broadcast;
  	else if (skb->pkt_type == PACKET_MULTICAST)
  		++rx_stats->multicast;
  	u64_stats_update_end(&rx_stats->syncp);
  
  	napi_gro_receive(&nvchan->napi, skb);
  	return NVSP_STAT_SUCCESS;
  }
  
  static void netvsc_get_drvinfo(struct net_device *net,
  			       struct ethtool_drvinfo *info)
  {
  	strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
  	strlcpy(info->fw_version, "N/A", sizeof(info->fw_version));
  }
  
  static void netvsc_get_channels(struct net_device *net,
  				struct ethtool_channels *channel)
  {
  	struct net_device_context *net_device_ctx = netdev_priv(net);
  	struct netvsc_device *nvdev = rtnl_dereference(net_device_ctx->nvdev);
  
  	if (nvdev) {
  		channel->max_combined	= nvdev->max_chn;
  		channel->combined_count = nvdev->num_chn;
  	}
  }
  
  /* Alloc struct netvsc_device_info, and initialize it from either existing
   * struct netvsc_device, or from default values.
   */
  static struct netvsc_device_info *netvsc_devinfo_get
  			(struct netvsc_device *nvdev)
  {
  	struct netvsc_device_info *dev_info;
  
  	dev_info = kzalloc(sizeof(*dev_info), GFP_ATOMIC);
  
  	if (!dev_info)
  		return NULL;
  
  	if (nvdev) {
  		dev_info->num_chn = nvdev->num_chn;
  		dev_info->send_sections = nvdev->send_section_cnt;
  		dev_info->send_section_size = nvdev->send_section_size;
  		dev_info->recv_sections = nvdev->recv_section_cnt;
  		dev_info->recv_section_size = nvdev->recv_section_size;
  
  		memcpy(dev_info->rss_key, nvdev->extension->rss_key,
  		       NETVSC_HASH_KEYLEN);
  	} else {
  		dev_info->num_chn = VRSS_CHANNEL_DEFAULT;
  		dev_info->send_sections = NETVSC_DEFAULT_TX;
  		dev_info->send_section_size = NETVSC_SEND_SECTION_SIZE;
  		dev_info->recv_sections = NETVSC_DEFAULT_RX;
  		dev_info->recv_section_size = NETVSC_RECV_SECTION_SIZE;
  	}
  
  	return dev_info;
  }
  
  static int netvsc_detach(struct net_device *ndev,
  			 struct netvsc_device *nvdev)
  {
  	struct net_device_context *ndev_ctx = netdev_priv(ndev);
  	struct hv_device *hdev = ndev_ctx->device_ctx;
  	int ret;
  
  	/* Don't try continuing to try and setup sub channels */
  	if (cancel_work_sync(&nvdev->subchan_work))
  		nvdev->num_chn = 1;
  
  	/* If device was up (receiving) then shutdown */
  	if (netif_running(ndev)) {
  		netvsc_tx_disable(nvdev, ndev);
  
  		ret = rndis_filter_close(nvdev);
  		if (ret) {
  			netdev_err(ndev,
  				   "unable to close device (ret %d).\n", ret);
  			return ret;
  		}
  
  		ret = netvsc_wait_until_empty(nvdev);
  		if (ret) {
  			netdev_err(ndev,
  				   "Ring buffer not empty after closing rndis\n");
  			return ret;
  		}
  	}
  
  	netif_device_detach(ndev);
  
  	rndis_filter_device_remove(hdev, nvdev);
  
  	return 0;
  }
  
  static int netvsc_attach(struct net_device *ndev,
  			 struct netvsc_device_info *dev_info)
  {
  	struct net_device_context *ndev_ctx = netdev_priv(ndev);
  	struct hv_device *hdev = ndev_ctx->device_ctx;
  	struct netvsc_device *nvdev;
  	struct rndis_device *rdev;
  	int ret;
  
  	nvdev = rndis_filter_device_add(hdev, dev_info);
  	if (IS_ERR(nvdev))
  		return PTR_ERR(nvdev);
  
  	if (nvdev->num_chn > 1) {
  		ret = rndis_set_subchannel(ndev, nvdev, dev_info);
  
  		/* if unavailable, just proceed with one queue */
  		if (ret) {
  			nvdev->max_chn = 1;
  			nvdev->num_chn = 1;
  		}
  	}
  
  	/* In any case device is now ready */
  	netif_device_attach(ndev);
  
  	/* Note: enable and attach happen when sub-channels setup */
  	netif_carrier_off(ndev);
  
  	if (netif_running(ndev)) {
  		ret = rndis_filter_open(nvdev);
  		if (ret)
  			return ret;
  
  		rdev = nvdev->extension;
  		if (!rdev->link_state)
  			netif_carrier_on(ndev);
  	}
  
  	return 0;
  }
  
  static int netvsc_set_channels(struct net_device *net,
  			       struct ethtool_channels *channels)
  {
  	struct net_device_context *net_device_ctx = netdev_priv(net);
  	struct netvsc_device *nvdev = rtnl_dereference(net_device_ctx->nvdev);
  	unsigned int orig, count = channels->combined_count;
  	struct netvsc_device_info *device_info;
  	int ret;
  
  	/* We do not support separate count for rx, tx, or other */
  	if (count == 0 ||
  	    channels->rx_count || channels->tx_count || channels->other_count)
  		return -EINVAL;
  
  	if (!nvdev || nvdev->destroy)
  		return -ENODEV;
  
  	if (nvdev->nvsp_version < NVSP_PROTOCOL_VERSION_5)
  		return -EINVAL;
  
  	if (count > nvdev->max_chn)
  		return -EINVAL;
  
  	orig = nvdev->num_chn;
  
  	device_info = netvsc_devinfo_get(nvdev);
  
  	if (!device_info)
  		return -ENOMEM;
  
  	device_info->num_chn = count;
  
  	ret = netvsc_detach(net, nvdev);
  	if (ret)
  		goto out;
  
  	ret = netvsc_attach(net, device_info);
  	if (ret) {
  		device_info->num_chn = orig;
  		if (netvsc_attach(net, device_info))
  			netdev_err(net, "restoring channel setting failed\n");
  	}
  
  out:
  	kfree(device_info);
  	return ret;
  }
  
  static bool
  netvsc_validate_ethtool_ss_cmd(const struct ethtool_link_ksettings *cmd)
  {
  	struct ethtool_link_ksettings diff1 = *cmd;
  	struct ethtool_link_ksettings diff2 = {};
  
  	diff1.base.speed = 0;
  	diff1.base.duplex = 0;
  	/* advertising and cmd are usually set */
  	ethtool_link_ksettings_zero_link_mode(&diff1, advertising);
  	diff1.base.cmd = 0;
  	/* We set port to PORT_OTHER */
  	diff2.base.port = PORT_OTHER;
  
  	return !memcmp(&diff1, &diff2, sizeof(diff1));
  }
  
  static void netvsc_init_settings(struct net_device *dev)
  {
  	struct net_device_context *ndc = netdev_priv(dev);
  
  	ndc->l4_hash = HV_DEFAULT_L4HASH;
  
  	ndc->speed = SPEED_UNKNOWN;
  	ndc->duplex = DUPLEX_FULL;
  
  	dev->features = NETIF_F_LRO;
  }
  
  static int netvsc_get_link_ksettings(struct net_device *dev,
  				     struct ethtool_link_ksettings *cmd)
  {
  	struct net_device_context *ndc = netdev_priv(dev);
  
  	cmd->base.speed = ndc->speed;
  	cmd->base.duplex = ndc->duplex;
  	cmd->base.port = PORT_OTHER;
  
  	return 0;
  }
  
  static int netvsc_set_link_ksettings(struct net_device *dev,
  				     const struct ethtool_link_ksettings *cmd)
  {
  	struct net_device_context *ndc = netdev_priv(dev);
  	u32 speed;
  
  	speed = cmd->base.speed;
  	if (!ethtool_validate_speed(speed) ||
  	    !ethtool_validate_duplex(cmd->base.duplex) ||
  	    !netvsc_validate_ethtool_ss_cmd(cmd))
  		return -EINVAL;
  
  	ndc->speed = speed;
  	ndc->duplex = cmd->base.duplex;
  
  	return 0;
  }
  
  static int netvsc_change_mtu(struct net_device *ndev, int mtu)
  {
  	struct net_device_context *ndevctx = netdev_priv(ndev);
  	struct net_device *vf_netdev = rtnl_dereference(ndevctx->vf_netdev);
  	struct netvsc_device *nvdev = rtnl_dereference(ndevctx->nvdev);
  	int orig_mtu = ndev->mtu;
  	struct netvsc_device_info *device_info;
  	int ret = 0;
  
  	if (!nvdev || nvdev->destroy)
  		return -ENODEV;
  
  	device_info = netvsc_devinfo_get(nvdev);
  
  	if (!device_info)
  		return -ENOMEM;
  
  	/* Change MTU of underlying VF netdev first. */
  	if (vf_netdev) {
  		ret = dev_set_mtu(vf_netdev, mtu);
  		if (ret)
  			goto out;
  	}
  
  	ret = netvsc_detach(ndev, nvdev);
  	if (ret)
  		goto rollback_vf;
  
  	ndev->mtu = mtu;
  
  	ret = netvsc_attach(ndev, device_info);
  	if (!ret)
  		goto out;
  
  	/* Attempt rollback to original MTU */
  	ndev->mtu = orig_mtu;
  
  	if (netvsc_attach(ndev, device_info))
  		netdev_err(ndev, "restoring mtu failed\n");
  rollback_vf:
  	if (vf_netdev)
  		dev_set_mtu(vf_netdev, orig_mtu);
  
  out:
  	kfree(device_info);
  	return ret;
  }
  
  static void netvsc_get_vf_stats(struct net_device *net,
  				struct netvsc_vf_pcpu_stats *tot)
  {
  	struct net_device_context *ndev_ctx = netdev_priv(net);
  	int i;
  
  	memset(tot, 0, sizeof(*tot));
  
  	for_each_possible_cpu(i) {
  		const struct netvsc_vf_pcpu_stats *stats
  			= per_cpu_ptr(ndev_ctx->vf_stats, i);
  		u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
  		unsigned int start;
  
  		do {
  			start = u64_stats_fetch_begin_irq(&stats->syncp);
  			rx_packets = stats->rx_packets;
  			tx_packets = stats->tx_packets;
  			rx_bytes = stats->rx_bytes;
  			tx_bytes = stats->tx_bytes;
  		} while (u64_stats_fetch_retry_irq(&stats->syncp, start));
  
  		tot->rx_packets += rx_packets;
  		tot->tx_packets += tx_packets;
  		tot->rx_bytes   += rx_bytes;
  		tot->tx_bytes   += tx_bytes;
  		tot->tx_dropped += stats->tx_dropped;
  	}
  }
  
  static void netvsc_get_pcpu_stats(struct net_device *net,
  				  struct netvsc_ethtool_pcpu_stats *pcpu_tot)
  {
  	struct net_device_context *ndev_ctx = netdev_priv(net);
  	struct netvsc_device *nvdev = rcu_dereference_rtnl(ndev_ctx->nvdev);
  	int i;
  
  	/* fetch percpu stats of vf */
  	for_each_possible_cpu(i) {
  		const struct netvsc_vf_pcpu_stats *stats =
  			per_cpu_ptr(ndev_ctx->vf_stats, i);
  		struct netvsc_ethtool_pcpu_stats *this_tot = &pcpu_tot[i];
  		unsigned int start;
  
  		do {
  			start = u64_stats_fetch_begin_irq(&stats->syncp);
  			this_tot->vf_rx_packets = stats->rx_packets;
  			this_tot->vf_tx_packets = stats->tx_packets;
  			this_tot->vf_rx_bytes = stats->rx_bytes;
  			this_tot->vf_tx_bytes = stats->tx_bytes;
  		} while (u64_stats_fetch_retry_irq(&stats->syncp, start));
  		this_tot->rx_packets = this_tot->vf_rx_packets;
  		this_tot->tx_packets = this_tot->vf_tx_packets;
  		this_tot->rx_bytes   = this_tot->vf_rx_bytes;
  		this_tot->tx_bytes   = this_tot->vf_tx_bytes;
  	}
  
  	/* fetch percpu stats of netvsc */
  	for (i = 0; i < nvdev->num_chn; i++) {
  		const struct netvsc_channel *nvchan = &nvdev->chan_table[i];
  		const struct netvsc_stats *stats;
  		struct netvsc_ethtool_pcpu_stats *this_tot =
  			&pcpu_tot[nvchan->channel->target_cpu];
  		u64 packets, bytes;
  		unsigned int start;
  
  		stats = &nvchan->tx_stats;
  		do {
  			start = u64_stats_fetch_begin_irq(&stats->syncp);
  			packets = stats->packets;
  			bytes = stats->bytes;
  		} while (u64_stats_fetch_retry_irq(&stats->syncp, start));
  
  		this_tot->tx_bytes	+= bytes;
  		this_tot->tx_packets	+= packets;
  
  		stats = &nvchan->rx_stats;
  		do {
  			start = u64_stats_fetch_begin_irq(&stats->syncp);
  			packets = stats->packets;
  			bytes = stats->bytes;
  		} while (u64_stats_fetch_retry_irq(&stats->syncp, start));
  
  		this_tot->rx_bytes	+= bytes;
  		this_tot->rx_packets	+= packets;
  	}
  }
  
  static void netvsc_get_stats64(struct net_device *net,
  			       struct rtnl_link_stats64 *t)
  {
  	struct net_device_context *ndev_ctx = netdev_priv(net);
  	struct netvsc_device *nvdev = rcu_dereference_rtnl(ndev_ctx->nvdev);
  	struct netvsc_vf_pcpu_stats vf_tot;
  	int i;
  
  	if (!nvdev)
  		return;
  
  	netdev_stats_to_stats64(t, &net->stats);
  
  	netvsc_get_vf_stats(net, &vf_tot);
  	t->rx_packets += vf_tot.rx_packets;
  	t->tx_packets += vf_tot.tx_packets;
  	t->rx_bytes   += vf_tot.rx_bytes;
  	t->tx_bytes   += vf_tot.tx_bytes;
  	t->tx_dropped += vf_tot.tx_dropped;
  
  	for (i = 0; i < nvdev->num_chn; i++) {
  		const struct netvsc_channel *nvchan = &nvdev->chan_table[i];
  		const struct netvsc_stats *stats;
  		u64 packets, bytes, multicast;
  		unsigned int start;
  
  		stats = &nvchan->tx_stats;
  		do {
  			start = u64_stats_fetch_begin_irq(&stats->syncp);
  			packets = stats->packets;
  			bytes = stats->bytes;
  		} while (u64_stats_fetch_retry_irq(&stats->syncp, start));
  
  		t->tx_bytes	+= bytes;
  		t->tx_packets	+= packets;
  
  		stats = &nvchan->rx_stats;
  		do {
  			start = u64_stats_fetch_begin_irq(&stats->syncp);
  			packets = stats->packets;
  			bytes = stats->bytes;
  			multicast = stats->multicast + stats->broadcast;
  		} while (u64_stats_fetch_retry_irq(&stats->syncp, start));
  
  		t->rx_bytes	+= bytes;
  		t->rx_packets	+= packets;
  		t->multicast	+= multicast;
  	}
  }
  
  static int netvsc_set_mac_addr(struct net_device *ndev, void *p)
  {
  	struct net_device_context *ndc = netdev_priv(ndev);
  	struct net_device *vf_netdev = rtnl_dereference(ndc->vf_netdev);
  	struct netvsc_device *nvdev = rtnl_dereference(ndc->nvdev);
  	struct sockaddr *addr = p;
  	int err;
  
  	err = eth_prepare_mac_addr_change(ndev, p);
  	if (err)
  		return err;
  
  	if (!nvdev)
  		return -ENODEV;
  
  	if (vf_netdev) {
  		err = dev_set_mac_address(vf_netdev, addr, NULL);
  		if (err)
  			return err;
  	}
  
  	err = rndis_filter_set_device_mac(nvdev, addr->sa_data);
  	if (!err) {
  		eth_commit_mac_addr_change(ndev, p);
  	} else if (vf_netdev) {
  		/* rollback change on VF */
  		memcpy(addr->sa_data, ndev->dev_addr, ETH_ALEN);
  		dev_set_mac_address(vf_netdev, addr, NULL);
  	}
  
  	return err;
  }
  
  static const struct {
  	char name[ETH_GSTRING_LEN];
  	u16 offset;
  } netvsc_stats[] = {
  	{ "tx_scattered", offsetof(struct netvsc_ethtool_stats, tx_scattered) },
  	{ "tx_no_memory", offsetof(struct netvsc_ethtool_stats, tx_no_memory) },
  	{ "tx_no_space",  offsetof(struct netvsc_ethtool_stats, tx_no_space) },
  	{ "tx_too_big",	  offsetof(struct netvsc_ethtool_stats, tx_too_big) },
  	{ "tx_busy",	  offsetof(struct netvsc_ethtool_stats, tx_busy) },
  	{ "tx_send_full", offsetof(struct netvsc_ethtool_stats, tx_send_full) },
  	{ "rx_comp_busy", offsetof(struct netvsc_ethtool_stats, rx_comp_busy) },
  	{ "rx_no_memory", offsetof(struct netvsc_ethtool_stats, rx_no_memory) },
  	{ "stop_queue", offsetof(struct netvsc_ethtool_stats, stop_queue) },
  	{ "wake_queue", offsetof(struct netvsc_ethtool_stats, wake_queue) },
  }, pcpu_stats[] = {
  	{ "cpu%u_rx_packets",
  		offsetof(struct netvsc_ethtool_pcpu_stats, rx_packets) },
  	{ "cpu%u_rx_bytes",
  		offsetof(struct netvsc_ethtool_pcpu_stats, rx_bytes) },
  	{ "cpu%u_tx_packets",
  		offsetof(struct netvsc_ethtool_pcpu_stats, tx_packets) },
  	{ "cpu%u_tx_bytes",
  		offsetof(struct netvsc_ethtool_pcpu_stats, tx_bytes) },
  	{ "cpu%u_vf_rx_packets",
  		offsetof(struct netvsc_ethtool_pcpu_stats, vf_rx_packets) },
  	{ "cpu%u_vf_rx_bytes",
  		offsetof(struct netvsc_ethtool_pcpu_stats, vf_rx_bytes) },
  	{ "cpu%u_vf_tx_packets",
  		offsetof(struct netvsc_ethtool_pcpu_stats, vf_tx_packets) },
  	{ "cpu%u_vf_tx_bytes",
  		offsetof(struct netvsc_ethtool_pcpu_stats, vf_tx_bytes) },
  }, vf_stats[] = {
  	{ "vf_rx_packets", offsetof(struct netvsc_vf_pcpu_stats, rx_packets) },
  	{ "vf_rx_bytes",   offsetof(struct netvsc_vf_pcpu_stats, rx_bytes) },
  	{ "vf_tx_packets", offsetof(struct netvsc_vf_pcpu_stats, tx_packets) },
  	{ "vf_tx_bytes",   offsetof(struct netvsc_vf_pcpu_stats, tx_bytes) },
  	{ "vf_tx_dropped", offsetof(struct netvsc_vf_pcpu_stats, tx_dropped) },
  };
  
  #define NETVSC_GLOBAL_STATS_LEN	ARRAY_SIZE(netvsc_stats)
  #define NETVSC_VF_STATS_LEN	ARRAY_SIZE(vf_stats)
  
  /* statistics per queue (rx/tx packets/bytes) */
  #define NETVSC_PCPU_STATS_LEN (num_present_cpus() * ARRAY_SIZE(pcpu_stats))
  
  /* 4 statistics per queue (rx/tx packets/bytes) */
  #define NETVSC_QUEUE_STATS_LEN(dev) ((dev)->num_chn * 4)
  
  static int netvsc_get_sset_count(struct net_device *dev, int string_set)
  {
  	struct net_device_context *ndc = netdev_priv(dev);
  	struct netvsc_device *nvdev = rtnl_dereference(ndc->nvdev);
  
  	if (!nvdev)
  		return -ENODEV;
  
  	switch (string_set) {
  	case ETH_SS_STATS:
  		return NETVSC_GLOBAL_STATS_LEN
  			+ NETVSC_VF_STATS_LEN
  			+ NETVSC_QUEUE_STATS_LEN(nvdev)
  			+ NETVSC_PCPU_STATS_LEN;
  	default:
  		return -EINVAL;
  	}
  }
  
  static void netvsc_get_ethtool_stats(struct net_device *dev,
  				     struct ethtool_stats *stats, u64 *data)
  {
  	struct net_device_context *ndc = netdev_priv(dev);
  	struct netvsc_device *nvdev = rtnl_dereference(ndc->nvdev);
  	const void *nds = &ndc->eth_stats;
  	const struct netvsc_stats *qstats;
  	struct netvsc_vf_pcpu_stats sum;
  	struct netvsc_ethtool_pcpu_stats *pcpu_sum;
  	unsigned int start;
  	u64 packets, bytes;
  	int i, j, cpu;
  
  	if (!nvdev)
  		return;
  
  	for (i = 0; i < NETVSC_GLOBAL_STATS_LEN; i++)
  		data[i] = *(unsigned long *)(nds + netvsc_stats[i].offset);
  
  	netvsc_get_vf_stats(dev, &sum);
  	for (j = 0; j < NETVSC_VF_STATS_LEN; j++)
  		data[i++] = *(u64 *)((void *)&sum + vf_stats[j].offset);
  
  	for (j = 0; j < nvdev->num_chn; j++) {
  		qstats = &nvdev->chan_table[j].tx_stats;
  
  		do {
  			start = u64_stats_fetch_begin_irq(&qstats->syncp);
  			packets = qstats->packets;
  			bytes = qstats->bytes;
  		} while (u64_stats_fetch_retry_irq(&qstats->syncp, start));
  		data[i++] = packets;
  		data[i++] = bytes;
  
  		qstats = &nvdev->chan_table[j].rx_stats;
  		do {
  			start = u64_stats_fetch_begin_irq(&qstats->syncp);
  			packets = qstats->packets;
  			bytes = qstats->bytes;
  		} while (u64_stats_fetch_retry_irq(&qstats->syncp, start));
  		data[i++] = packets;
  		data[i++] = bytes;
  	}
  
  	pcpu_sum = kvmalloc_array(num_possible_cpus(),
  				  sizeof(struct netvsc_ethtool_pcpu_stats),
  				  GFP_KERNEL);
  	netvsc_get_pcpu_stats(dev, pcpu_sum);
  	for_each_present_cpu(cpu) {
  		struct netvsc_ethtool_pcpu_stats *this_sum = &pcpu_sum[cpu];
  
  		for (j = 0; j < ARRAY_SIZE(pcpu_stats); j++)
  			data[i++] = *(u64 *)((void *)this_sum
  					     + pcpu_stats[j].offset);
  	}
  	kvfree(pcpu_sum);
  }
  
  static void netvsc_get_strings(struct net_device *dev, u32 stringset, u8 *data)
  {
  	struct net_device_context *ndc = netdev_priv(dev);
  	struct netvsc_device *nvdev = rtnl_dereference(ndc->nvdev);
  	u8 *p = data;
  	int i, cpu;
  
  	if (!nvdev)
  		return;
  
  	switch (stringset) {
  	case ETH_SS_STATS:
  		for (i = 0; i < ARRAY_SIZE(netvsc_stats); i++) {
  			memcpy(p, netvsc_stats[i].name, ETH_GSTRING_LEN);
  			p += ETH_GSTRING_LEN;
  		}
  
  		for (i = 0; i < ARRAY_SIZE(vf_stats); i++) {
  			memcpy(p, vf_stats[i].name, ETH_GSTRING_LEN);
  			p += ETH_GSTRING_LEN;
  		}
  
  		for (i = 0; i < nvdev->num_chn; i++) {
  			sprintf(p, "tx_queue_%u_packets", i);
  			p += ETH_GSTRING_LEN;
  			sprintf(p, "tx_queue_%u_bytes", i);
  			p += ETH_GSTRING_LEN;
  			sprintf(p, "rx_queue_%u_packets", i);
  			p += ETH_GSTRING_LEN;
  			sprintf(p, "rx_queue_%u_bytes", i);
  			p += ETH_GSTRING_LEN;
  		}
  
  		for_each_present_cpu(cpu) {
  			for (i = 0; i < ARRAY_SIZE(pcpu_stats); i++) {
  				sprintf(p, pcpu_stats[i].name, cpu);
  				p += ETH_GSTRING_LEN;
  			}
  		}
  
  		break;
  	}
  }
  
  static int
  netvsc_get_rss_hash_opts(struct net_device_context *ndc,
  			 struct ethtool_rxnfc *info)
  {
  	const u32 l4_flag = RXH_L4_B_0_1 | RXH_L4_B_2_3;
  
  	info->data = RXH_IP_SRC | RXH_IP_DST;
  
  	switch (info->flow_type) {
  	case TCP_V4_FLOW:
  		if (ndc->l4_hash & HV_TCP4_L4HASH)
  			info->data |= l4_flag;
  
  		break;
  
  	case TCP_V6_FLOW:
  		if (ndc->l4_hash & HV_TCP6_L4HASH)
  			info->data |= l4_flag;
  
  		break;
  
  	case UDP_V4_FLOW:
  		if (ndc->l4_hash & HV_UDP4_L4HASH)
  			info->data |= l4_flag;
  
  		break;
  
  	case UDP_V6_FLOW:
  		if (ndc->l4_hash & HV_UDP6_L4HASH)
  			info->data |= l4_flag;
  
  		break;
  
  	case IPV4_FLOW:
  	case IPV6_FLOW:
  		break;
  	default:
  		info->data = 0;
  		break;
  	}
  
  	return 0;
  }
  
  static int
  netvsc_get_rxnfc(struct net_device *dev, struct ethtool_rxnfc *info,
  		 u32 *rules)
  {
  	struct net_device_context *ndc = netdev_priv(dev);
  	struct netvsc_device *nvdev = rtnl_dereference(ndc->nvdev);
  
  	if (!nvdev)
  		return -ENODEV;
  
  	switch (info->cmd) {
  	case ETHTOOL_GRXRINGS:
  		info->data = nvdev->num_chn;
  		return 0;
  
  	case ETHTOOL_GRXFH:
  		return netvsc_get_rss_hash_opts(ndc, info);
  	}
  	return -EOPNOTSUPP;
  }
  
  static int netvsc_set_rss_hash_opts(struct net_device_context *ndc,
  				    struct ethtool_rxnfc *info)
  {
  	if (info->data == (RXH_IP_SRC | RXH_IP_DST |
  			   RXH_L4_B_0_1 | RXH_L4_B_2_3)) {
  		switch (info->flow_type) {
  		case TCP_V4_FLOW:
  			ndc->l4_hash |= HV_TCP4_L4HASH;
  			break;
  
  		case TCP_V6_FLOW:
  			ndc->l4_hash |= HV_TCP6_L4HASH;
  			break;
  
  		case UDP_V4_FLOW:
  			ndc->l4_hash |= HV_UDP4_L4HASH;
  			break;
  
  		case UDP_V6_FLOW:
  			ndc->l4_hash |= HV_UDP6_L4HASH;
  			break;
  
  		default:
  			return -EOPNOTSUPP;
  		}
  
  		return 0;
  	}
  
  	if (info->data == (RXH_IP_SRC | RXH_IP_DST)) {
  		switch (info->flow_type) {
  		case TCP_V4_FLOW:
  			ndc->l4_hash &= ~HV_TCP4_L4HASH;
  			break;
  
  		case TCP_V6_FLOW:
  			ndc->l4_hash &= ~HV_TCP6_L4HASH;
  			break;
  
  		case UDP_V4_FLOW:
  			ndc->l4_hash &= ~HV_UDP4_L4HASH;
  			break;
  
  		case UDP_V6_FLOW:
  			ndc->l4_hash &= ~HV_UDP6_L4HASH;
  			break;
  
  		default:
  			return -EOPNOTSUPP;
  		}
  
  		return 0;
  	}
  
  	return -EOPNOTSUPP;
  }
  
  static int
  netvsc_set_rxnfc(struct net_device *ndev, struct ethtool_rxnfc *info)
  {
  	struct net_device_context *ndc = netdev_priv(ndev);
  
  	if (info->cmd == ETHTOOL_SRXFH)
  		return netvsc_set_rss_hash_opts(ndc, info);
  
  	return -EOPNOTSUPP;
  }
  
  static u32 netvsc_get_rxfh_key_size(struct net_device *dev)
  {
  	return NETVSC_HASH_KEYLEN;
  }
  
  static u32 netvsc_rss_indir_size(struct net_device *dev)
  {
  	return ITAB_NUM;
  }
  
  static int netvsc_get_rxfh(struct net_device *dev, u32 *indir, u8 *key,
  			   u8 *hfunc)
  {
  	struct net_device_context *ndc = netdev_priv(dev);
  	struct netvsc_device *ndev = rtnl_dereference(ndc->nvdev);
  	struct rndis_device *rndis_dev;
  	int i;
  
  	if (!ndev)
  		return -ENODEV;
  
  	if (hfunc)
  		*hfunc = ETH_RSS_HASH_TOP;	/* Toeplitz */
  
  	rndis_dev = ndev->extension;
  	if (indir) {
  		for (i = 0; i < ITAB_NUM; i++)
  			indir[i] = rndis_dev->rx_table[i];
  	}
  
  	if (key)
  		memcpy(key, rndis_dev->rss_key, NETVSC_HASH_KEYLEN);
  
  	return 0;
  }
  
  static int netvsc_set_rxfh(struct net_device *dev, const u32 *indir,
  			   const u8 *key, const u8 hfunc)
  {
  	struct net_device_context *ndc = netdev_priv(dev);
  	struct netvsc_device *ndev = rtnl_dereference(ndc->nvdev);
  	struct rndis_device *rndis_dev;
  	int i;
  
  	if (!ndev)
  		return -ENODEV;
  
  	if (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP)
  		return -EOPNOTSUPP;
  
  	rndis_dev = ndev->extension;
  	if (indir) {
  		for (i = 0; i < ITAB_NUM; i++)
  			if (indir[i] >= ndev->num_chn)
  				return -EINVAL;
  
  		for (i = 0; i < ITAB_NUM; i++)
  			rndis_dev->rx_table[i] = indir[i];
  	}
  
  	if (!key) {
  		if (!indir)
  			return 0;
  
  		key = rndis_dev->rss_key;
  	}
  
  	return rndis_filter_set_rss_param(rndis_dev, key);
  }
  
  /* Hyper-V RNDIS protocol does not have ring in the HW sense.
   * It does have pre-allocated receive area which is divided into sections.
   */
  static void __netvsc_get_ringparam(struct netvsc_device *nvdev,
  				   struct ethtool_ringparam *ring)
  {
  	u32 max_buf_size;
  
  	ring->rx_pending = nvdev->recv_section_cnt;
  	ring->tx_pending = nvdev->send_section_cnt;
  
  	if (nvdev->nvsp_version <= NVSP_PROTOCOL_VERSION_2)
  		max_buf_size = NETVSC_RECEIVE_BUFFER_SIZE_LEGACY;
  	else
  		max_buf_size = NETVSC_RECEIVE_BUFFER_SIZE;
  
  	ring->rx_max_pending = max_buf_size / nvdev->recv_section_size;
  	ring->tx_max_pending = NETVSC_SEND_BUFFER_SIZE
  		/ nvdev->send_section_size;
  }
  
  static void netvsc_get_ringparam(struct net_device *ndev,
  				 struct ethtool_ringparam *ring)
  {
  	struct net_device_context *ndevctx = netdev_priv(ndev);
  	struct netvsc_device *nvdev = rtnl_dereference(ndevctx->nvdev);
  
  	if (!nvdev)
  		return;
  
  	__netvsc_get_ringparam(nvdev, ring);
  }
  
  static int netvsc_set_ringparam(struct net_device *ndev,
  				struct ethtool_ringparam *ring)
  {
  	struct net_device_context *ndevctx = netdev_priv(ndev);
  	struct netvsc_device *nvdev = rtnl_dereference(ndevctx->nvdev);
  	struct netvsc_device_info *device_info;
  	struct ethtool_ringparam orig;
  	u32 new_tx, new_rx;
  	int ret = 0;
  
  	if (!nvdev || nvdev->destroy)
  		return -ENODEV;
  
  	memset(&orig, 0, sizeof(orig));
  	__netvsc_get_ringparam(nvdev, &orig);
  
  	new_tx = clamp_t(u32, ring->tx_pending,
  			 NETVSC_MIN_TX_SECTIONS, orig.tx_max_pending);
  	new_rx = clamp_t(u32, ring->rx_pending,
  			 NETVSC_MIN_RX_SECTIONS, orig.rx_max_pending);
  
  	if (new_tx == orig.tx_pending &&
  	    new_rx == orig.rx_pending)
  		return 0;	 /* no change */
  
  	device_info = netvsc_devinfo_get(nvdev);
  
  	if (!device_info)
  		return -ENOMEM;
  
  	device_info->send_sections = new_tx;
  	device_info->recv_sections = new_rx;
  
  	ret = netvsc_detach(ndev, nvdev);
  	if (ret)
  		goto out;
  
  	ret = netvsc_attach(ndev, device_info);
  	if (ret) {
  		device_info->send_sections = orig.tx_pending;
  		device_info->recv_sections = orig.rx_pending;
  
  		if (netvsc_attach(ndev, device_info))
  			netdev_err(ndev, "restoring ringparam failed");
  	}
  
  out:
  	kfree(device_info);
  	return ret;
  }
  
  static int netvsc_set_features(struct net_device *ndev,
  			       netdev_features_t features)
  {
  	netdev_features_t change = features ^ ndev->features;
  	struct net_device_context *ndevctx = netdev_priv(ndev);
  	struct netvsc_device *nvdev = rtnl_dereference(ndevctx->nvdev);
  	struct ndis_offload_params offloads;
  
  	if (!nvdev || nvdev->destroy)
  		return -ENODEV;
  
  	if (!(change & NETIF_F_LRO))
  		return 0;
  
  	memset(&offloads, 0, sizeof(struct ndis_offload_params));
  
  	if (features & NETIF_F_LRO) {
  		offloads.rsc_ip_v4 = NDIS_OFFLOAD_PARAMETERS_RSC_ENABLED;
  		offloads.rsc_ip_v6 = NDIS_OFFLOAD_PARAMETERS_RSC_ENABLED;
  	} else {
  		offloads.rsc_ip_v4 = NDIS_OFFLOAD_PARAMETERS_RSC_DISABLED;
  		offloads.rsc_ip_v6 = NDIS_OFFLOAD_PARAMETERS_RSC_DISABLED;
  	}
  
  	return rndis_filter_set_offload_params(ndev, nvdev, &offloads);
  }
  
  static u32 netvsc_get_msglevel(struct net_device *ndev)
  {
  	struct net_device_context *ndev_ctx = netdev_priv(ndev);
  
  	return ndev_ctx->msg_enable;
  }
  
  static void netvsc_set_msglevel(struct net_device *ndev, u32 val)
  {
  	struct net_device_context *ndev_ctx = netdev_priv(ndev);
  
  	ndev_ctx->msg_enable = val;
  }
  
  static const struct ethtool_ops ethtool_ops = {
  	.get_drvinfo	= netvsc_get_drvinfo,
  	.get_msglevel	= netvsc_get_msglevel,
  	.set_msglevel	= netvsc_set_msglevel,
  	.get_link	= ethtool_op_get_link,
  	.get_ethtool_stats = netvsc_get_ethtool_stats,
  	.get_sset_count = netvsc_get_sset_count,
  	.get_strings	= netvsc_get_strings,
  	.get_channels   = netvsc_get_channels,
  	.set_channels   = netvsc_set_channels,
  	.get_ts_info	= ethtool_op_get_ts_info,
  	.get_rxnfc	= netvsc_get_rxnfc,
  	.set_rxnfc	= netvsc_set_rxnfc,
  	.get_rxfh_key_size = netvsc_get_rxfh_key_size,
  	.get_rxfh_indir_size = netvsc_rss_indir_size,
  	.get_rxfh	= netvsc_get_rxfh,
  	.set_rxfh	= netvsc_set_rxfh,
  	.get_link_ksettings = netvsc_get_link_ksettings,
  	.set_link_ksettings = netvsc_set_link_ksettings,
  	.get_ringparam	= netvsc_get_ringparam,
  	.set_ringparam	= netvsc_set_ringparam,
  };
  
  static const struct net_device_ops device_ops = {
  	.ndo_open =			netvsc_open,
  	.ndo_stop =			netvsc_close,
  	.ndo_start_xmit =		netvsc_start_xmit,
  	.ndo_change_rx_flags =		netvsc_change_rx_flags,
  	.ndo_set_rx_mode =		netvsc_set_rx_mode,
  	.ndo_set_features =		netvsc_set_features,
  	.ndo_change_mtu =		netvsc_change_mtu,
  	.ndo_validate_addr =		eth_validate_addr,
  	.ndo_set_mac_address =		netvsc_set_mac_addr,
  	.ndo_select_queue =		netvsc_select_queue,
  	.ndo_get_stats64 =		netvsc_get_stats64,
  };
  
  /*
   * Handle link status changes. For RNDIS_STATUS_NETWORK_CHANGE emulate link
   * down/up sequence. In case of RNDIS_STATUS_MEDIA_CONNECT when carrier is
   * present send GARP packet to network peers with netif_notify_peers().
   */
  static void netvsc_link_change(struct work_struct *w)
  {
  	struct net_device_context *ndev_ctx =
  		container_of(w, struct net_device_context, dwork.work);
  	struct hv_device *device_obj = ndev_ctx->device_ctx;
  	struct net_device *net = hv_get_drvdata(device_obj);
  	struct netvsc_device *net_device;
  	struct rndis_device *rdev;
  	struct netvsc_reconfig *event = NULL;
  	bool notify = false, reschedule = false;
  	unsigned long flags, next_reconfig, delay;
  
  	/* if changes are happening, comeback later */
  	if (!rtnl_trylock()) {
  		schedule_delayed_work(&ndev_ctx->dwork, LINKCHANGE_INT);
  		return;
  	}
  
  	net_device = rtnl_dereference(ndev_ctx->nvdev);
  	if (!net_device)
  		goto out_unlock;
  
  	rdev = net_device->extension;
  
  	next_reconfig = ndev_ctx->last_reconfig + LINKCHANGE_INT;
  	if (time_is_after_jiffies(next_reconfig)) {
  		/* link_watch only sends one notification with current state
  		 * per second, avoid doing reconfig more frequently. Handle
  		 * wrap around.
  		 */
  		delay = next_reconfig - jiffies;
  		delay = delay < LINKCHANGE_INT ? delay : LINKCHANGE_INT;
  		schedule_delayed_work(&ndev_ctx->dwork, delay);
  		goto out_unlock;
  	}
  	ndev_ctx->last_reconfig = jiffies;
  
  	spin_lock_irqsave(&ndev_ctx->lock, flags);
  	if (!list_empty(&ndev_ctx->reconfig_events)) {
  		event = list_first_entry(&ndev_ctx->reconfig_events,
  					 struct netvsc_reconfig, list);
  		list_del(&event->list);
  		reschedule = !list_empty(&ndev_ctx->reconfig_events);
  	}
  	spin_unlock_irqrestore(&ndev_ctx->lock, flags);
  
  	if (!event)
  		goto out_unlock;
  
  	switch (event->event) {
  		/* Only the following events are possible due to the check in
  		 * netvsc_linkstatus_callback()
  		 */
  	case RNDIS_STATUS_MEDIA_CONNECT:
  		if (rdev->link_state) {
  			rdev->link_state = false;
  			netif_carrier_on(net);
  			netvsc_tx_enable(net_device, net);
  		} else {
  			notify = true;
  		}
  		kfree(event);
  		break;
  	case RNDIS_STATUS_MEDIA_DISCONNECT:
  		if (!rdev->link_state) {
  			rdev->link_state = true;
  			netif_carrier_off(net);
  			netvsc_tx_disable(net_device, net);
  		}
  		kfree(event);
  		break;
  	case RNDIS_STATUS_NETWORK_CHANGE:
  		/* Only makes sense if carrier is present */
  		if (!rdev->link_state) {
  			rdev->link_state = true;
  			netif_carrier_off(net);
  			netvsc_tx_disable(net_device, net);
  			event->event = RNDIS_STATUS_MEDIA_CONNECT;
  			spin_lock_irqsave(&ndev_ctx->lock, flags);
  			list_add(&event->list, &ndev_ctx->reconfig_events);
  			spin_unlock_irqrestore(&ndev_ctx->lock, flags);
  			reschedule = true;
  		}
  		break;
  	}
  
  	rtnl_unlock();
  
  	if (notify)
  		netdev_notify_peers(net);
  
  	/* link_watch only sends one notification with current state per
  	 * second, handle next reconfig event in 2 seconds.
  	 */
  	if (reschedule)
  		schedule_delayed_work(&ndev_ctx->dwork, LINKCHANGE_INT);
  
  	return;
  
  out_unlock:
  	rtnl_unlock();
  }
  
  static struct net_device *get_netvsc_byref(struct net_device *vf_netdev)
  {
  	struct net_device_context *net_device_ctx;
  	struct net_device *dev;
  
  	dev = netdev_master_upper_dev_get(vf_netdev);
  	if (!dev || dev->netdev_ops != &device_ops)
  		return NULL;	/* not a netvsc device */
  
  	net_device_ctx = netdev_priv(dev);
  	if (!rtnl_dereference(net_device_ctx->nvdev))
  		return NULL;	/* device is removed */
  
  	return dev;
  }
  
  /* Called when VF is injecting data into network stack.
   * Change the associated network device from VF to netvsc.
   * note: already called with rcu_read_lock
   */
  static rx_handler_result_t netvsc_vf_handle_frame(struct sk_buff **pskb)
  {
  	struct sk_buff *skb = *pskb;
  	struct net_device *ndev = rcu_dereference(skb->dev->rx_handler_data);
  	struct net_device_context *ndev_ctx = netdev_priv(ndev);
  	struct netvsc_vf_pcpu_stats *pcpu_stats
  		 = this_cpu_ptr(ndev_ctx->vf_stats);
  
  	skb = skb_share_check(skb, GFP_ATOMIC);
  	if (unlikely(!skb))
  		return RX_HANDLER_CONSUMED;
  
  	*pskb = skb;
  
  	skb->dev = ndev;
  
  	u64_stats_update_begin(&pcpu_stats->syncp);
  	pcpu_stats->rx_packets++;
  	pcpu_stats->rx_bytes += skb->len;
  	u64_stats_update_end(&pcpu_stats->syncp);
  
  	return RX_HANDLER_ANOTHER;
  }
  
  static int netvsc_vf_join(struct net_device *vf_netdev,
  			  struct net_device *ndev)
  {
  	struct net_device_context *ndev_ctx = netdev_priv(ndev);
  	int ret;
  
  	ret = netdev_rx_handler_register(vf_netdev,
  					 netvsc_vf_handle_frame, ndev);
  	if (ret != 0) {
  		netdev_err(vf_netdev,
  			   "can not register netvsc VF receive handler (err = %d)\n",
  			   ret);
  		goto rx_handler_failed;
  	}
  
  	ret = netdev_master_upper_dev_link(vf_netdev, ndev,
  					   NULL, NULL, NULL);
  	if (ret != 0) {
  		netdev_err(vf_netdev,
  			   "can not set master device %s (err = %d)\n",
  			   ndev->name, ret);
  		goto upper_link_failed;
  	}
  
  	/* set slave flag before open to prevent IPv6 addrconf */
  	vf_netdev->flags |= IFF_SLAVE;
  
  	schedule_delayed_work(&ndev_ctx->vf_takeover, VF_TAKEOVER_INT);
  
  	call_netdevice_notifiers(NETDEV_JOIN, vf_netdev);
  
  	netdev_info(vf_netdev, "joined to %s\n", ndev->name);
  	return 0;
  
  upper_link_failed:
  	netdev_rx_handler_unregister(vf_netdev);
  rx_handler_failed:
  	return ret;
  }
  
  static void __netvsc_vf_setup(struct net_device *ndev,
  			      struct net_device *vf_netdev)
  {
  	int ret;
  
  	/* Align MTU of VF with master */
  	ret = dev_set_mtu(vf_netdev, ndev->mtu);
  	if (ret)
  		netdev_warn(vf_netdev,
  			    "unable to change mtu to %u\n", ndev->mtu);
  
  	/* set multicast etc flags on VF */
  	dev_change_flags(vf_netdev, ndev->flags | IFF_SLAVE, NULL);
  
  	/* sync address list from ndev to VF */
  	netif_addr_lock_bh(ndev);
  	dev_uc_sync(vf_netdev, ndev);
  	dev_mc_sync(vf_netdev, ndev);
  	netif_addr_unlock_bh(ndev);
  
  	if (netif_running(ndev)) {
  		ret = dev_open(vf_netdev, NULL);
  		if (ret)
  			netdev_warn(vf_netdev,
  				    "unable to open: %d\n", ret);
  	}
  }
  
  /* Setup VF as slave of the synthetic device.
   * Runs in workqueue to avoid recursion in netlink callbacks.
   */
  static void netvsc_vf_setup(struct work_struct *w)
  {
  	struct net_device_context *ndev_ctx
  		= container_of(w, struct net_device_context, vf_takeover.work);
  	struct net_device *ndev = hv_get_drvdata(ndev_ctx->device_ctx);
  	struct net_device *vf_netdev;
  
  	if (!rtnl_trylock()) {
  		schedule_delayed_work(&ndev_ctx->vf_takeover, 0);
  		return;
  	}
  
  	vf_netdev = rtnl_dereference(ndev_ctx->vf_netdev);
  	if (vf_netdev)
  		__netvsc_vf_setup(ndev, vf_netdev);
  
  	rtnl_unlock();
  }
  
  /* Find netvsc by VF serial number.
   * The PCI hyperv controller records the serial number as the slot kobj name.
   */
  static struct net_device *get_netvsc_byslot(const struct net_device *vf_netdev)
  {
  	struct device *parent = vf_netdev->dev.parent;
  	struct net_device_context *ndev_ctx;
  	struct pci_dev *pdev;
  	u32 serial;
  
  	if (!parent || !dev_is_pci(parent))
  		return NULL; /* not a PCI device */
  
  	pdev = to_pci_dev(parent);
  	if (!pdev->slot) {
  		netdev_notice(vf_netdev, "no PCI slot information\n");
  		return NULL;
  	}
  
  	if (kstrtou32(pci_slot_name(pdev->slot), 10, &serial)) {
  		netdev_notice(vf_netdev, "Invalid vf serial:%s\n",
  			      pci_slot_name(pdev->slot));
  		return NULL;
  	}
  
  	list_for_each_entry(ndev_ctx, &netvsc_dev_list, list) {
  		if (!ndev_ctx->vf_alloc)
  			continue;
  
  		if (ndev_ctx->vf_serial == serial)
  			return hv_get_drvdata(ndev_ctx->device_ctx);
  	}
  
  	netdev_notice(vf_netdev,
  		      "no netdev found for vf serial:%u\n", serial);
  	return NULL;
  }
  
  static int netvsc_register_vf(struct net_device *vf_netdev)
  {
  	struct net_device_context *net_device_ctx;
  	struct netvsc_device *netvsc_dev;
  	struct net_device *ndev;
  	int ret;
  
  	if (vf_netdev->addr_len != ETH_ALEN)
  		return NOTIFY_DONE;
  
  	ndev = get_netvsc_byslot(vf_netdev);
  	if (!ndev)
  		return NOTIFY_DONE;
  
  	net_device_ctx = netdev_priv(ndev);
  	netvsc_dev = rtnl_dereference(net_device_ctx->nvdev);
  	if (!netvsc_dev || rtnl_dereference(net_device_ctx->vf_netdev))
  		return NOTIFY_DONE;
  
  	/* if synthetic interface is a different namespace,
  	 * then move the VF to that namespace; join will be
  	 * done again in that context.
  	 */
  	if (!net_eq(dev_net(ndev), dev_net(vf_netdev))) {
  		ret = dev_change_net_namespace(vf_netdev,
  					       dev_net(ndev), "eth%d");
  		if (ret)
  			netdev_err(vf_netdev,
  				   "could not move to same namespace as %s: %d\n",
  				   ndev->name, ret);
  		else
  			netdev_info(vf_netdev,
  				    "VF moved to namespace with: %s\n",
  				    ndev->name);
  		return NOTIFY_DONE;
  	}
  
  	netdev_info(ndev, "VF registering: %s\n", vf_netdev->name);
  
  	if (netvsc_vf_join(vf_netdev, ndev) != 0)
  		return NOTIFY_DONE;
  
  	dev_hold(vf_netdev);
  	rcu_assign_pointer(net_device_ctx->vf_netdev, vf_netdev);
  	return NOTIFY_OK;
  }
  
  /* VF up/down change detected, schedule to change data path */
  static int netvsc_vf_changed(struct net_device *vf_netdev)
  {
  	struct net_device_context *net_device_ctx;
  	struct netvsc_device *netvsc_dev;
  	struct net_device *ndev;
  	bool vf_is_up = netif_running(vf_netdev);
  
  	ndev = get_netvsc_byref(vf_netdev);
  	if (!ndev)
  		return NOTIFY_DONE;
  
  	net_device_ctx = netdev_priv(ndev);
  	netvsc_dev = rtnl_dereference(net_device_ctx->nvdev);
  	if (!netvsc_dev)
  		return NOTIFY_DONE;
  
  	netvsc_switch_datapath(ndev, vf_is_up);
  	netdev_info(ndev, "Data path switched %s VF: %s\n",
  		    vf_is_up ? "to" : "from", vf_netdev->name);
  
  	return NOTIFY_OK;
  }
  
  static int netvsc_unregister_vf(struct net_device *vf_netdev)
  {
  	struct net_device *ndev;
  	struct net_device_context *net_device_ctx;
  
  	ndev = get_netvsc_byref(vf_netdev);
  	if (!ndev)
  		return NOTIFY_DONE;
  
  	net_device_ctx = netdev_priv(ndev);
  	cancel_delayed_work_sync(&net_device_ctx->vf_takeover);
  
  	netdev_info(ndev, "VF unregistering: %s\n", vf_netdev->name);
  
  	netdev_rx_handler_unregister(vf_netdev);
  	netdev_upper_dev_unlink(vf_netdev, ndev);
  	RCU_INIT_POINTER(net_device_ctx->vf_netdev, NULL);
  	dev_put(vf_netdev);
  
  	return NOTIFY_OK;
  }
  
  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 = NULL;
  	struct netvsc_device *nvdev;
  	int ret = -ENOMEM;
  
  	net = alloc_etherdev_mq(sizeof(struct net_device_context),
  				VRSS_CHANNEL_MAX);
  	if (!net)
  		goto no_net;
  
  	netif_carrier_off(net);
  
  	netvsc_init_settings(net);
  
  	net_device_ctx = netdev_priv(net);
  	net_device_ctx->device_ctx = dev;
  	net_device_ctx->msg_enable = netif_msg_init(debug, default_msg);
  	if (netif_msg_probe(net_device_ctx))
  		netdev_dbg(net, "netvsc msg_enable: %d\n",
  			   net_device_ctx->msg_enable);
  
  	hv_set_drvdata(dev, net);
  
  	INIT_DELAYED_WORK(&net_device_ctx->dwork, netvsc_link_change);
  
  	spin_lock_init(&net_device_ctx->lock);
  	INIT_LIST_HEAD(&net_device_ctx->reconfig_events);
  	INIT_DELAYED_WORK(&net_device_ctx->vf_takeover, netvsc_vf_setup);
  
  	net_device_ctx->vf_stats
  		= netdev_alloc_pcpu_stats(struct netvsc_vf_pcpu_stats);
  	if (!net_device_ctx->vf_stats)
  		goto no_stats;
  
  	net->netdev_ops = &device_ops;
  	net->ethtool_ops = &ethtool_ops;
  	SET_NETDEV_DEV(net, &dev->device);
  
  	/* We always need headroom for rndis header */
  	net->needed_headroom = RNDIS_AND_PPI_SIZE;
  
  	/* Initialize the number of queues to be 1, we may change it if more
  	 * channels are offered later.
  	 */
  	netif_set_real_num_tx_queues(net, 1);
  	netif_set_real_num_rx_queues(net, 1);
  
  	/* Notify the netvsc driver of the new device */
  	device_info = netvsc_devinfo_get(NULL);
  
  	if (!device_info) {
  		ret = -ENOMEM;
  		goto devinfo_failed;
  	}
  
  	nvdev = rndis_filter_device_add(dev, device_info);
  	if (IS_ERR(nvdev)) {
  		ret = PTR_ERR(nvdev);
  		netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);
  		goto rndis_failed;
  	}
  
  	memcpy(net->dev_addr, device_info->mac_adr, ETH_ALEN);
  
  	/* We must get rtnl lock before scheduling nvdev->subchan_work,
  	 * otherwise netvsc_subchan_work() can get rtnl lock first and wait
  	 * all subchannels to show up, but that may not happen because
  	 * netvsc_probe() can't get rtnl lock and as a result vmbus_onoffer()
  	 * -> ... -> device_add() -> ... -> __device_attach() can't get
  	 * the device lock, so all the subchannels can't be processed --
  	 * finally netvsc_subchan_work() hangs forever.
  	 */
  	rtnl_lock();
  
  	if (nvdev->num_chn > 1)
  		schedule_work(&nvdev->subchan_work);
  
  	/* hw_features computed in rndis_netdev_set_hwcaps() */
  	net->features = net->hw_features |
  		NETIF_F_HIGHDMA | NETIF_F_SG |
  		NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX;
  	net->vlan_features = net->features;
  
  	netdev_lockdep_set_classes(net);
  
  	/* MTU range: 68 - 1500 or 65521 */
  	net->min_mtu = NETVSC_MTU_MIN;
  	if (nvdev->nvsp_version >= NVSP_PROTOCOL_VERSION_2)
  		net->max_mtu = NETVSC_MTU - ETH_HLEN;
  	else
  		net->max_mtu = ETH_DATA_LEN;
  
  	ret = register_netdevice(net);
  	if (ret != 0) {
  		pr_err("Unable to register netdev.\n");
  		goto register_failed;
  	}
  
  	list_add(&net_device_ctx->list, &netvsc_dev_list);
  	rtnl_unlock();
  
  	kfree(device_info);
  	return 0;
  
  register_failed:
  	rtnl_unlock();
  	rndis_filter_device_remove(dev, nvdev);
  rndis_failed:
  	kfree(device_info);
  devinfo_failed:
  	free_percpu(net_device_ctx->vf_stats);
  no_stats:
  	hv_set_drvdata(dev, NULL);
  	free_netdev(net);
  no_net:
  	return ret;
  }
  
  static int netvsc_remove(struct hv_device *dev)
  {
  	struct net_device_context *ndev_ctx;
  	struct net_device *vf_netdev, *net;
  	struct netvsc_device *nvdev;
  
  	net = hv_get_drvdata(dev);
  	if (net == NULL) {
  		dev_err(&dev->device, "No net device to remove\n");
  		return 0;
  	}
  
  	ndev_ctx = netdev_priv(net);
  
  	cancel_delayed_work_sync(&ndev_ctx->dwork);
  
  	rtnl_lock();
  	nvdev = rtnl_dereference(ndev_ctx->nvdev);
  	if (nvdev)
  		cancel_work_sync(&nvdev->subchan_work);
  
  	/*
  	 * Call to the vsc driver to let it know that the device is being
  	 * removed. Also blocks mtu and channel changes.
  	 */
  	vf_netdev = rtnl_dereference(ndev_ctx->vf_netdev);
  	if (vf_netdev)
  		netvsc_unregister_vf(vf_netdev);
  
  	if (nvdev)
  		rndis_filter_device_remove(dev, nvdev);
  
  	unregister_netdevice(net);
  	list_del(&ndev_ctx->list);
  
  	rtnl_unlock();
  
  	hv_set_drvdata(dev, NULL);
  
  	free_percpu(ndev_ctx->vf_stats);
  	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,
  	.driver = {
  		.probe_type = PROBE_FORCE_SYNCHRONOUS,
  	},
  };
  
  /*
   * On Hyper-V, every VF interface is matched with a corresponding
   * synthetic interface. The synthetic interface is presented first
   * to the guest. When the corresponding VF instance is registered,
   * we will take care of switching the data path.
   */
  static int netvsc_netdev_event(struct notifier_block *this,
  			       unsigned long event, void *ptr)
  {
  	struct net_device *event_dev = netdev_notifier_info_to_dev(ptr);
  
  	/* Skip our own events */
  	if (event_dev->netdev_ops == &device_ops)
  		return NOTIFY_DONE;
  
  	/* Avoid non-Ethernet type devices */
  	if (event_dev->type != ARPHRD_ETHER)
  		return NOTIFY_DONE;
  
  	/* Avoid Vlan dev with same MAC registering as VF */
  	if (is_vlan_dev(event_dev))
  		return NOTIFY_DONE;
  
  	/* Avoid Bonding master dev with same MAC registering as VF */
  	if ((event_dev->priv_flags & IFF_BONDING) &&
  	    (event_dev->flags & IFF_MASTER))
  		return NOTIFY_DONE;
  
  	switch (event) {
  	case NETDEV_REGISTER:
  		return netvsc_register_vf(event_dev);
  	case NETDEV_UNREGISTER:
  		return netvsc_unregister_vf(event_dev);
  	case NETDEV_UP:
  	case NETDEV_DOWN:
  		return netvsc_vf_changed(event_dev);
  	default:
  		return NOTIFY_DONE;
  	}
  }
  
  static struct notifier_block netvsc_netdev_notifier = {
  	.notifier_call = netvsc_netdev_event,
  };
  
  static void __exit netvsc_drv_exit(void)
  {
  	unregister_netdevice_notifier(&netvsc_netdev_notifier);
  	vmbus_driver_unregister(&netvsc_drv);
  }
  
  static int __init netvsc_drv_init(void)
  {
  	int ret;
  
  	if (ring_size < RING_SIZE_MIN) {
  		ring_size = RING_SIZE_MIN;
  		pr_info("Increased ring_size to %u (min allowed)\n",
  			ring_size);
  	}
  	netvsc_ring_bytes = ring_size * PAGE_SIZE;
  
  	ret = vmbus_driver_register(&netvsc_drv);
  	if (ret)
  		return ret;
  
  	register_netdevice_notifier(&netvsc_netdev_notifier);
  	return 0;
  }
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("Microsoft Hyper-V network driver");
  
  module_init(netvsc_drv_init);
  module_exit(netvsc_drv_exit);
  