text: /*
   * 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, see <http://www.gnu.org/licenses/>.
   *
   * Authors:
   *   Haiyang Zhang <haiyangz@microsoft.com>
   *   Hank Janssen  <hjanssen@microsoft.com>
   */
  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  
  #include <linux/kernel.h>
  #include <linux/sched.h>
  #include <linux/wait.h>
  #include <linux/mm.h>
  #include <linux/delay.h>
  #include <linux/io.h>
  #include <linux/slab.h>
  #include <linux/netdevice.h>
  #include <linux/if_ether.h>
  #include <linux/vmalloc.h>
  #include <asm/sync_bitops.h>
  
  #include "hyperv_net.h"
  
  /*
   * Switch the data path from the synthetic interface to the VF
   * interface.
   */
  void netvsc_switch_datapath(struct net_device *ndev, bool vf)
  {
  	struct net_device_context *net_device_ctx = netdev_priv(ndev);
  	struct hv_device *dev = net_device_ctx->device_ctx;
  	struct netvsc_device *nv_dev = net_device_ctx->nvdev;
  	struct nvsp_message *init_pkt = &nv_dev->channel_init_pkt;
  
  	memset(init_pkt, 0, sizeof(struct nvsp_message));
  	init_pkt->hdr.msg_type = NVSP_MSG4_TYPE_SWITCH_DATA_PATH;
  	if (vf)
  		init_pkt->msg.v4_msg.active_dp.active_datapath =
  			NVSP_DATAPATH_VF;
  	else
  		init_pkt->msg.v4_msg.active_dp.active_datapath =
  			NVSP_DATAPATH_SYNTHETIC;
  
  	vmbus_sendpacket(dev->channel, init_pkt,
  			       sizeof(struct nvsp_message),
  			       (unsigned long)init_pkt,
  			       VM_PKT_DATA_INBAND, 0);
  
  	net_device_ctx->datapath = vf;
  }
  
  static struct netvsc_device *alloc_net_device(void)
  {
  	struct netvsc_device *net_device;
  
  	net_device = kzalloc(sizeof(struct netvsc_device), GFP_KERNEL);
  	if (!net_device)
  		return NULL;
  
  	net_device->chan_table[0].mrc.buf
  		= vzalloc(NETVSC_RECVSLOT_MAX * sizeof(struct recv_comp_data));
  
  	init_waitqueue_head(&net_device->wait_drain);
  	net_device->destroy = false;
  	atomic_set(&net_device->open_cnt, 0);
  	net_device->max_pkt = RNDIS_MAX_PKT_DEFAULT;
  	net_device->pkt_align = RNDIS_PKT_ALIGN_DEFAULT;
  	init_completion(&net_device->channel_init_wait);
  	init_waitqueue_head(&net_device->subchan_open);
  
  	return net_device;
  }
  
  static void free_netvsc_device(struct rcu_head *head)
  {
  	struct netvsc_device *nvdev
  		= container_of(head, struct netvsc_device, rcu);
  	int i;
  
  	for (i = 0; i < VRSS_CHANNEL_MAX; i++)
  		vfree(nvdev->chan_table[i].mrc.buf);
  
  	kfree(nvdev);
  }
  
  static void free_netvsc_device_rcu(struct netvsc_device *nvdev)
  {
  	call_rcu(&nvdev->rcu, free_netvsc_device);
  }
  
  static void netvsc_destroy_buf(struct hv_device *device)
  {
  	struct nvsp_message *revoke_packet;
  	struct net_device *ndev = hv_get_drvdata(device);
  	struct netvsc_device *net_device = net_device_to_netvsc_device(ndev);
  	int ret;
  
  	/*
  	 * If we got a section count, it means we received a
  	 * SendReceiveBufferComplete msg (ie sent
  	 * NvspMessage1TypeSendReceiveBuffer msg) therefore, we need
  	 * to send a revoke msg here
  	 */
  	if (net_device->recv_section_cnt) {
  		/* Send the revoke receive buffer */
  		revoke_packet = &net_device->revoke_packet;
  		memset(revoke_packet, 0, sizeof(struct nvsp_message));
  
  		revoke_packet->hdr.msg_type =
  			NVSP_MSG1_TYPE_REVOKE_RECV_BUF;
  		revoke_packet->msg.v1_msg.
  		revoke_recv_buf.id = NETVSC_RECEIVE_BUFFER_ID;
  
  		ret = vmbus_sendpacket(device->channel,
  				       revoke_packet,
  				       sizeof(struct nvsp_message),
  				       (unsigned long)revoke_packet,
  				       VM_PKT_DATA_INBAND, 0);
  		/* If the failure is because the channel is rescinded;
  		 * ignore the failure since we cannot send on a rescinded
  		 * channel. This would allow us to properly cleanup
  		 * even when the channel is rescinded.
  		 */
  		if (device->channel->rescind)
  			ret = 0;
  		/*
  		 * If we failed here, we might as well return and
  		 * have a leak rather than continue and a bugchk
  		 */
  		if (ret != 0) {
  			netdev_err(ndev, "unable to send "
  				"revoke receive buffer to netvsp\n");
  			return;
  		}
  	}
  
  	/* Teardown the gpadl on the vsp end */
  	if (net_device->recv_buf_gpadl_handle) {
  		ret = vmbus_teardown_gpadl(device->channel,
  					   net_device->recv_buf_gpadl_handle);
  
  		/* If we failed here, we might as well return and have a leak
  		 * rather than continue and a bugchk
  		 */
  		if (ret != 0) {
  			netdev_err(ndev,
  				   "unable to teardown receive buffer's gpadl\n");
  			return;
  		}
  		net_device->recv_buf_gpadl_handle = 0;
  	}
  
  	if (net_device->recv_buf) {
  		/* Free up the receive buffer */
  		vfree(net_device->recv_buf);
  		net_device->recv_buf = NULL;
  	}
  
  	if (net_device->recv_section) {
  		net_device->recv_section_cnt = 0;
  		kfree(net_device->recv_section);
  		net_device->recv_section = NULL;
  	}
  
  	/* Deal with the send buffer we may have setup.
  	 * If we got a  send section size, it means we received a
  	 * NVSP_MSG1_TYPE_SEND_SEND_BUF_COMPLETE msg (ie sent
  	 * NVSP_MSG1_TYPE_SEND_SEND_BUF msg) therefore, we need
  	 * to send a revoke msg here
  	 */
  	if (net_device->send_section_size) {
  		/* Send the revoke receive buffer */
  		revoke_packet = &net_device->revoke_packet;
  		memset(revoke_packet, 0, sizeof(struct nvsp_message));
  
  		revoke_packet->hdr.msg_type =
  			NVSP_MSG1_TYPE_REVOKE_SEND_BUF;
  		revoke_packet->msg.v1_msg.revoke_send_buf.id =
  			NETVSC_SEND_BUFFER_ID;
  
  		ret = vmbus_sendpacket(device->channel,
  				       revoke_packet,
  				       sizeof(struct nvsp_message),
  				       (unsigned long)revoke_packet,
  				       VM_PKT_DATA_INBAND, 0);
  
  		/* If the failure is because the channel is rescinded;
  		 * ignore the failure since we cannot send on a rescinded
  		 * channel. This would allow us to properly cleanup
  		 * even when the channel is rescinded.
  		 */
  		if (device->channel->rescind)
  			ret = 0;
  
  		/* If we failed here, we might as well return and
  		 * have a leak rather than continue and a bugchk
  		 */
  		if (ret != 0) {
  			netdev_err(ndev, "unable to send "
  				   "revoke send buffer to netvsp\n");
  			return;
  		}
  	}
  	/* Teardown the gpadl on the vsp end */
  	if (net_device->send_buf_gpadl_handle) {
  		ret = vmbus_teardown_gpadl(device->channel,
  					   net_device->send_buf_gpadl_handle);
  
  		/* If we failed here, we might as well return and have a leak
  		 * rather than continue and a bugchk
  		 */
  		if (ret != 0) {
  			netdev_err(ndev,
  				   "unable to teardown send buffer's gpadl\n");
  			return;
  		}
  		net_device->send_buf_gpadl_handle = 0;
  	}
  	if (net_device->send_buf) {
  		/* Free up the send buffer */
  		vfree(net_device->send_buf);
  		net_device->send_buf = NULL;
  	}
  	kfree(net_device->send_section_map);
  }
  
  static int netvsc_init_buf(struct hv_device *device,
  			   struct netvsc_device *net_device)
  {
  	int ret = 0;
  	struct nvsp_message *init_packet;
  	struct net_device *ndev;
  	size_t map_words;
  	int node;
  
  	ndev = hv_get_drvdata(device);
  
  	node = cpu_to_node(device->channel->target_cpu);
  	net_device->recv_buf = vzalloc_node(net_device->recv_buf_size, node);
  	if (!net_device->recv_buf)
  		net_device->recv_buf = vzalloc(net_device->recv_buf_size);
  
  	if (!net_device->recv_buf) {
  		netdev_err(ndev, "unable to allocate receive "
  			"buffer of size %d\n", net_device->recv_buf_size);
  		ret = -ENOMEM;
  		goto cleanup;
  	}
  
  	/*
  	 * Establish the gpadl handle for this buffer on this
  	 * channel.  Note: This call uses the vmbus connection rather
  	 * than the channel to establish the gpadl handle.
  	 */
  	ret = vmbus_establish_gpadl(device->channel, net_device->recv_buf,
  				    net_device->recv_buf_size,
  				    &net_device->recv_buf_gpadl_handle);
  	if (ret != 0) {
  		netdev_err(ndev,
  			"unable to establish receive buffer's gpadl\n");
  		goto cleanup;
  	}
  
  	/* Notify the NetVsp of the gpadl handle */
  	init_packet = &net_device->channel_init_pkt;
  	memset(init_packet, 0, sizeof(struct nvsp_message));
  	init_packet->hdr.msg_type = NVSP_MSG1_TYPE_SEND_RECV_BUF;
  	init_packet->msg.v1_msg.send_recv_buf.
  		gpadl_handle = net_device->recv_buf_gpadl_handle;
  	init_packet->msg.v1_msg.
  		send_recv_buf.id = NETVSC_RECEIVE_BUFFER_ID;
  
  	/* Send the gpadl notification request */
  	ret = vmbus_sendpacket(device->channel, init_packet,
  			       sizeof(struct nvsp_message),
  			       (unsigned long)init_packet,
  			       VM_PKT_DATA_INBAND,
  			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
  	if (ret != 0) {
  		netdev_err(ndev,
  			"unable to send receive buffer's gpadl to netvsp\n");
  		goto cleanup;
  	}
  
  	wait_for_completion(&net_device->channel_init_wait);
  
  	/* Check the response */
  	if (init_packet->msg.v1_msg.
  	    send_recv_buf_complete.status != NVSP_STAT_SUCCESS) {
  		netdev_err(ndev, "Unable to complete receive buffer "
  			   "initialization with NetVsp - status %d\n",
  			   init_packet->msg.v1_msg.
  			   send_recv_buf_complete.status);
  		ret = -EINVAL;
  		goto cleanup;
  	}
  
  	/* Parse the response */
  
  	net_device->recv_section_cnt = init_packet->msg.
  		v1_msg.send_recv_buf_complete.num_sections;
  
  	net_device->recv_section = kmemdup(
  		init_packet->msg.v1_msg.send_recv_buf_complete.sections,
  		net_device->recv_section_cnt *
  		sizeof(struct nvsp_1_receive_buffer_section),
  		GFP_KERNEL);
  	if (net_device->recv_section == NULL) {
  		ret = -EINVAL;
  		goto cleanup;
  	}
  
  	/*
  	 * For 1st release, there should only be 1 section that represents the
  	 * entire receive buffer
  	 */
  	if (net_device->recv_section_cnt != 1 ||
  	    net_device->recv_section->offset != 0) {
  		ret = -EINVAL;
  		goto cleanup;
  	}
  
  	/* Now setup the send buffer.
  	 */
  	net_device->send_buf = vzalloc_node(net_device->send_buf_size, node);
  	if (!net_device->send_buf)
  		net_device->send_buf = vzalloc(net_device->send_buf_size);
  	if (!net_device->send_buf) {
  		netdev_err(ndev, "unable to allocate send "
  			   "buffer of size %d\n", net_device->send_buf_size);
  		ret = -ENOMEM;
  		goto cleanup;
  	}
  
  	/* Establish the gpadl handle for this buffer on this
  	 * channel.  Note: This call uses the vmbus connection rather
  	 * than the channel to establish the gpadl handle.
  	 */
  	ret = vmbus_establish_gpadl(device->channel, net_device->send_buf,
  				    net_device->send_buf_size,
  				    &net_device->send_buf_gpadl_handle);
  	if (ret != 0) {
  		netdev_err(ndev,
  			   "unable to establish send buffer's gpadl\n");
  		goto cleanup;
  	}
  
  	/* Notify the NetVsp of the gpadl handle */
  	init_packet = &net_device->channel_init_pkt;
  	memset(init_packet, 0, sizeof(struct nvsp_message));
  	init_packet->hdr.msg_type = NVSP_MSG1_TYPE_SEND_SEND_BUF;
  	init_packet->msg.v1_msg.send_send_buf.gpadl_handle =
  		net_device->send_buf_gpadl_handle;
  	init_packet->msg.v1_msg.send_send_buf.id = NETVSC_SEND_BUFFER_ID;
  
  	/* Send the gpadl notification request */
  	ret = vmbus_sendpacket(device->channel, init_packet,
  			       sizeof(struct nvsp_message),
  			       (unsigned long)init_packet,
  			       VM_PKT_DATA_INBAND,
  			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
  	if (ret != 0) {
  		netdev_err(ndev,
  			   "unable to send send buffer's gpadl to netvsp\n");
  		goto cleanup;
  	}
  
  	wait_for_completion(&net_device->channel_init_wait);
  
  	/* Check the response */
  	if (init_packet->msg.v1_msg.
  	    send_send_buf_complete.status != NVSP_STAT_SUCCESS) {
  		netdev_err(ndev, "Unable to complete send buffer "
  			   "initialization with NetVsp - status %d\n",
  			   init_packet->msg.v1_msg.
  			   send_send_buf_complete.status);
  		ret = -EINVAL;
  		goto cleanup;
  	}
  
  	/* Parse the response */
  	net_device->send_section_size = init_packet->msg.
  				v1_msg.send_send_buf_complete.section_size;
  
  	/* Section count is simply the size divided by the section size.
  	 */
  	net_device->send_section_cnt =
  		net_device->send_buf_size / net_device->send_section_size;
  
  	netdev_dbg(ndev, "Send section size: %d, Section count:%d\n",
  		   net_device->send_section_size, net_device->send_section_cnt);
  
  	/* Setup state for managing the send buffer. */
  	map_words = DIV_ROUND_UP(net_device->send_section_cnt, BITS_PER_LONG);
  
  	net_device->send_section_map = kcalloc(map_words, sizeof(ulong), GFP_KERNEL);
  	if (net_device->send_section_map == NULL) {
  		ret = -ENOMEM;
  		goto cleanup;
  	}
  
  	goto exit;
  
  cleanup:
  	netvsc_destroy_buf(device);
  
  exit:
  	return ret;
  }
  
  /* Negotiate NVSP protocol version */
  static int negotiate_nvsp_ver(struct hv_device *device,
  			      struct netvsc_device *net_device,
  			      struct nvsp_message *init_packet,
  			      u32 nvsp_ver)
  {
  	struct net_device *ndev = hv_get_drvdata(device);
  	int ret;
  
  	memset(init_packet, 0, sizeof(struct nvsp_message));
  	init_packet->hdr.msg_type = NVSP_MSG_TYPE_INIT;
  	init_packet->msg.init_msg.init.min_protocol_ver = nvsp_ver;
  	init_packet->msg.init_msg.init.max_protocol_ver = nvsp_ver;
  
  	/* Send the init request */
  	ret = vmbus_sendpacket(device->channel, init_packet,
  			       sizeof(struct nvsp_message),
  			       (unsigned long)init_packet,
  			       VM_PKT_DATA_INBAND,
  			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
  
  	if (ret != 0)
  		return ret;
  
  	wait_for_completion(&net_device->channel_init_wait);
  
  	if (init_packet->msg.init_msg.init_complete.status !=
  	    NVSP_STAT_SUCCESS)
  		return -EINVAL;
  
  	if (nvsp_ver == NVSP_PROTOCOL_VERSION_1)
  		return 0;
  
  	/* NVSPv2 or later: Send NDIS config */
  	memset(init_packet, 0, sizeof(struct nvsp_message));
  	init_packet->hdr.msg_type = NVSP_MSG2_TYPE_SEND_NDIS_CONFIG;
  	init_packet->msg.v2_msg.send_ndis_config.mtu = ndev->mtu + ETH_HLEN;
  	init_packet->msg.v2_msg.send_ndis_config.capability.ieee8021q = 1;
  
  	if (nvsp_ver >= NVSP_PROTOCOL_VERSION_5) {
  		init_packet->msg.v2_msg.send_ndis_config.capability.sriov = 1;
  
  		/* Teaming bit is needed to receive link speed updates */
  		init_packet->msg.v2_msg.send_ndis_config.capability.teaming = 1;
  	}
  
  	ret = vmbus_sendpacket(device->channel, init_packet,
  				sizeof(struct nvsp_message),
  				(unsigned long)init_packet,
  				VM_PKT_DATA_INBAND, 0);
  
  	return ret;
  }
  
  static int netvsc_connect_vsp(struct hv_device *device,
  			      struct netvsc_device *net_device)
  {
  	const u32 ver_list[] = {
  		NVSP_PROTOCOL_VERSION_1, NVSP_PROTOCOL_VERSION_2,
  		NVSP_PROTOCOL_VERSION_4, NVSP_PROTOCOL_VERSION_5
  	};
  	struct nvsp_message *init_packet;
  	int ndis_version, i, ret;
  
  	init_packet = &net_device->channel_init_pkt;
  
  	/* Negotiate the latest NVSP protocol supported */
  	for (i = ARRAY_SIZE(ver_list) - 1; i >= 0; i--)
  		if (negotiate_nvsp_ver(device, net_device, init_packet,
  				       ver_list[i])  == 0) {
  			net_device->nvsp_version = ver_list[i];
  			break;
  		}
  
  	if (i < 0) {
  		ret = -EPROTO;
  		goto cleanup;
  	}
  
  	pr_debug("Negotiated NVSP version:%x\n", net_device->nvsp_version);
  
  	/* Send the ndis version */
  	memset(init_packet, 0, sizeof(struct nvsp_message));
  
  	if (net_device->nvsp_version <= NVSP_PROTOCOL_VERSION_4)
  		ndis_version = 0x00060001;
  	else
  		ndis_version = 0x0006001e;
  
  	init_packet->hdr.msg_type = NVSP_MSG1_TYPE_SEND_NDIS_VER;
  	init_packet->msg.v1_msg.
  		send_ndis_ver.ndis_major_ver =
  				(ndis_version & 0xFFFF0000) >> 16;
  	init_packet->msg.v1_msg.
  		send_ndis_ver.ndis_minor_ver =
  				ndis_version & 0xFFFF;
  
  	/* Send the init request */
  	ret = vmbus_sendpacket(device->channel, init_packet,
  				sizeof(struct nvsp_message),
  				(unsigned long)init_packet,
  				VM_PKT_DATA_INBAND, 0);
  	if (ret != 0)
  		goto cleanup;
  
  	/* Post the big receive buffer to NetVSP */
  	if (net_device->nvsp_version <= NVSP_PROTOCOL_VERSION_2)
  		net_device->recv_buf_size = NETVSC_RECEIVE_BUFFER_SIZE_LEGACY;
  	else
  		net_device->recv_buf_size = NETVSC_RECEIVE_BUFFER_SIZE;
  	net_device->send_buf_size = NETVSC_SEND_BUFFER_SIZE;
  
  	ret = netvsc_init_buf(device, net_device);
  
  cleanup:
  	return ret;
  }
  
  static void netvsc_disconnect_vsp(struct hv_device *device)
  {
  	netvsc_destroy_buf(device);
  }
  
  /*
   * netvsc_device_remove - Callback when the root bus device is removed
   */
  void netvsc_device_remove(struct hv_device *device)
  {
  	struct net_device *ndev = hv_get_drvdata(device);
  	struct net_device_context *net_device_ctx = netdev_priv(ndev);
  	struct netvsc_device *net_device = net_device_ctx->nvdev;
  	int i;
  
  	netvsc_disconnect_vsp(device);
  
  	RCU_INIT_POINTER(net_device_ctx->nvdev, NULL);
  
  	/*
  	 * At this point, no one should be accessing net_device
  	 * except in here
  	 */
  	netdev_dbg(ndev, "net device safe to remove\n");
  
  	/* Now, we can close the channel safely */
  	vmbus_close(device->channel);
  
  	/* And dissassociate NAPI context from device */
  	for (i = 0; i < net_device->num_chn; i++)
  		netif_napi_del(&net_device->chan_table[i].napi);
  
  	/* Release all resources */
  	free_netvsc_device_rcu(net_device);
  }
  
  #define RING_AVAIL_PERCENT_HIWATER 20
  #define RING_AVAIL_PERCENT_LOWATER 10
  
  /*
   * Get the percentage of available bytes to write in the ring.
   * The return value is in range from 0 to 100.
   */
  static inline u32 hv_ringbuf_avail_percent(
  		struct hv_ring_buffer_info *ring_info)
  {
  	u32 avail_read, avail_write;
  
  	hv_get_ringbuffer_availbytes(ring_info, &avail_read, &avail_write);
  
  	return avail_write * 100 / ring_info->ring_datasize;
  }
  
  static inline void netvsc_free_send_slot(struct netvsc_device *net_device,
  					 u32 index)
  {
  	sync_change_bit(index, net_device->send_section_map);
  }
  
  static void netvsc_send_tx_complete(struct netvsc_device *net_device,
  				    struct vmbus_channel *incoming_channel,
  				    struct hv_device *device,
  				    const struct vmpacket_descriptor *desc,
  				    int budget)
  {
  	struct sk_buff *skb = (struct sk_buff *)(unsigned long)desc->trans_id;
  	struct net_device *ndev = hv_get_drvdata(device);
  	struct vmbus_channel *channel = device->channel;
  	u16 q_idx = 0;
  	int queue_sends;
  
  	/* Notify the layer above us */
  	if (likely(skb)) {
  		const struct hv_netvsc_packet *packet
  			= (struct hv_netvsc_packet *)skb->cb;
  		u32 send_index = packet->send_buf_index;
  		struct netvsc_stats *tx_stats;
  
  		if (send_index != NETVSC_INVALID_INDEX)
  			netvsc_free_send_slot(net_device, send_index);
  		q_idx = packet->q_idx;
  		channel = incoming_channel;
  
  		tx_stats = &net_device->chan_table[q_idx].tx_stats;
  
  		u64_stats_update_begin(&tx_stats->syncp);
  		tx_stats->packets += packet->total_packets;
  		tx_stats->bytes += packet->total_bytes;
  		u64_stats_update_end(&tx_stats->syncp);
  
  		napi_consume_skb(skb, budget);
  	}
  
  	queue_sends =
  		atomic_dec_return(&net_device->chan_table[q_idx].queue_sends);
  
  	if (net_device->destroy && queue_sends == 0)
  		wake_up(&net_device->wait_drain);
  
  	if (netif_tx_queue_stopped(netdev_get_tx_queue(ndev, q_idx)) &&
  	    (hv_ringbuf_avail_percent(&channel->outbound) > RING_AVAIL_PERCENT_HIWATER ||
  	     queue_sends < 1))
  		netif_tx_wake_queue(netdev_get_tx_queue(ndev, q_idx));
  }
  
  static void netvsc_send_completion(struct netvsc_device *net_device,
  				   struct vmbus_channel *incoming_channel,
  				   struct hv_device *device,
  				   const struct vmpacket_descriptor *desc,
  				   int budget)
  {
  	struct nvsp_message *nvsp_packet = hv_pkt_data(desc);
  	struct net_device *ndev = hv_get_drvdata(device);
  
  	switch (nvsp_packet->hdr.msg_type) {
  	case NVSP_MSG_TYPE_INIT_COMPLETE:
  	case NVSP_MSG1_TYPE_SEND_RECV_BUF_COMPLETE:
  	case NVSP_MSG1_TYPE_SEND_SEND_BUF_COMPLETE:
  	case NVSP_MSG5_TYPE_SUBCHANNEL:
  		/* Copy the response back */
  		memcpy(&net_device->channel_init_pkt, nvsp_packet,
  		       sizeof(struct nvsp_message));
  		complete(&net_device->channel_init_wait);
  		break;
  
  	case NVSP_MSG1_TYPE_SEND_RNDIS_PKT_COMPLETE:
  		netvsc_send_tx_complete(net_device, incoming_channel,
  					device, desc, budget);
  		break;
  
  	default:
  		netdev_err(ndev,
  			   "Unknown send completion type %d received!!\n",
  			   nvsp_packet->hdr.msg_type);
  	}
  }
  
  static u32 netvsc_get_next_send_section(struct netvsc_device *net_device)
  {
  	unsigned long *map_addr = net_device->send_section_map;
  	unsigned int i;
  
  	for_each_clear_bit(i, map_addr, net_device->send_section_cnt) {
  		if (sync_test_and_set_bit(i, map_addr) == 0)
  			return i;
  	}
  
  	return NETVSC_INVALID_INDEX;
  }
  
  static u32 netvsc_copy_to_send_buf(struct netvsc_device *net_device,
  				   unsigned int section_index,
  				   u32 pend_size,
  				   struct hv_netvsc_packet *packet,
  				   struct rndis_message *rndis_msg,
  				   struct hv_page_buffer **pb,
  				   struct sk_buff *skb)
  {
  	char *start = net_device->send_buf;
  	char *dest = start + (section_index * net_device->send_section_size)
  		     + pend_size;
  	int i;
  	u32 msg_size = 0;
  	u32 padding = 0;
  	u32 remain = packet->total_data_buflen % net_device->pkt_align;
  	u32 page_count = packet->cp_partial ? packet->rmsg_pgcnt :
  		packet->page_buf_cnt;
  
  	/* Add padding */
  	if (skb->xmit_more && remain && !packet->cp_partial) {
  		padding = net_device->pkt_align - remain;
  		rndis_msg->msg_len += padding;
  		packet->total_data_buflen += padding;
  	}
  
  	for (i = 0; i < page_count; i++) {
  		char *src = phys_to_virt((*pb)[i].pfn << PAGE_SHIFT);
  		u32 offset = (*pb)[i].offset;
  		u32 len = (*pb)[i].len;
  
  		memcpy(dest, (src + offset), len);
  		msg_size += len;
  		dest += len;
  	}
  
  	if (padding) {
  		memset(dest, 0, padding);
  		msg_size += padding;
  	}
  
  	return msg_size;
  }
  
  static inline int netvsc_send_pkt(
  	struct hv_device *device,
  	struct hv_netvsc_packet *packet,
  	struct netvsc_device *net_device,
  	struct hv_page_buffer **pb,
  	struct sk_buff *skb)
  {
  	struct nvsp_message nvmsg;
  	struct netvsc_channel *nvchan
  		= &net_device->chan_table[packet->q_idx];
  	struct vmbus_channel *out_channel = nvchan->channel;
  	struct net_device *ndev = hv_get_drvdata(device);
  	struct netdev_queue *txq = netdev_get_tx_queue(ndev, packet->q_idx);
  	u64 req_id;
  	int ret;
  	struct hv_page_buffer *pgbuf;
  	u32 ring_avail = hv_ringbuf_avail_percent(&out_channel->outbound);
  
  	nvmsg.hdr.msg_type = NVSP_MSG1_TYPE_SEND_RNDIS_PKT;
  	if (skb != NULL) {
  		/* 0 is RMC_DATA; */
  		nvmsg.msg.v1_msg.send_rndis_pkt.channel_type = 0;
  	} else {
  		/* 1 is RMC_CONTROL; */
  		nvmsg.msg.v1_msg.send_rndis_pkt.channel_type = 1;
  	}
  
  	nvmsg.msg.v1_msg.send_rndis_pkt.send_buf_section_index =
  		packet->send_buf_index;
  	if (packet->send_buf_index == NETVSC_INVALID_INDEX)
  		nvmsg.msg.v1_msg.send_rndis_pkt.send_buf_section_size = 0;
  	else
  		nvmsg.msg.v1_msg.send_rndis_pkt.send_buf_section_size =
  			packet->total_data_buflen;
  
  	req_id = (ulong)skb;
  
  	if (out_channel->rescind)
  		return -ENODEV;
  
  	if (packet->page_buf_cnt) {
  		pgbuf = packet->cp_partial ? (*pb) +
  			packet->rmsg_pgcnt : (*pb);
  		ret = vmbus_sendpacket_pagebuffer_ctl(out_channel,
  						      pgbuf,
  						      packet->page_buf_cnt,
  						      &nvmsg,
  						      sizeof(struct nvsp_message),
  						      req_id,
  						      VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
  	} else {
  		ret = vmbus_sendpacket_ctl(out_channel, &nvmsg,
  					   sizeof(struct nvsp_message),
  					   req_id,
  					   VM_PKT_DATA_INBAND,
  					   VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
  	}
  
  	if (ret == 0) {
  		atomic_inc_return(&nvchan->queue_sends);
  
  		if (ring_avail < RING_AVAIL_PERCENT_LOWATER)
  			netif_tx_stop_queue(txq);
  	} else if (ret == -EAGAIN) {
  		netif_tx_stop_queue(txq);
  		if (atomic_read(&nvchan->queue_sends) < 1) {
  			netif_tx_wake_queue(txq);
  			ret = -ENOSPC;
  		}
  	} else {
  		netdev_err(ndev, "Unable to send packet %p ret %d\n",
  			   packet, ret);
  	}
  
  	return ret;
  }
  
  /* Move packet out of multi send data (msd), and clear msd */
  static inline void move_pkt_msd(struct hv_netvsc_packet **msd_send,
  				struct sk_buff **msd_skb,
  				struct multi_send_data *msdp)
  {
  	*msd_skb = msdp->skb;
  	*msd_send = msdp->pkt;
  	msdp->skb = NULL;
  	msdp->pkt = NULL;
  	msdp->count = 0;
  }
  
  int netvsc_send(struct hv_device *device,
  		struct hv_netvsc_packet *packet,
  		struct rndis_message *rndis_msg,
  		struct hv_page_buffer **pb,
  		struct sk_buff *skb)
  {
  	struct netvsc_device *net_device = hv_device_to_netvsc_device(device);
  	int ret = 0;
  	struct netvsc_channel *nvchan;
  	u32 pktlen = packet->total_data_buflen, msd_len = 0;
  	unsigned int section_index = NETVSC_INVALID_INDEX;
  	struct multi_send_data *msdp;
  	struct hv_netvsc_packet *msd_send = NULL, *cur_send = NULL;
  	struct sk_buff *msd_skb = NULL;
  	bool try_batch;
  	bool xmit_more = (skb != NULL) ? skb->xmit_more : false;
  
  	/* If device is rescinded, return error and packet will get dropped. */
  	if (unlikely(net_device->destroy))
  		return -ENODEV;
  
  	/* We may race with netvsc_connect_vsp()/netvsc_init_buf() and get
  	 * here before the negotiation with the host is finished and
  	 * send_section_map may not be allocated yet.
  	 */
  	if (unlikely(!net_device->send_section_map))
  		return -EAGAIN;
  
  	nvchan = &net_device->chan_table[packet->q_idx];
  	packet->send_buf_index = NETVSC_INVALID_INDEX;
  	packet->cp_partial = false;
  
  	/* Send control message directly without accessing msd (Multi-Send
  	 * Data) field which may be changed during data packet processing.
  	 */
  	if (!skb) {
  		cur_send = packet;
  		goto send_now;
  	}
  
  	/* batch packets in send buffer if possible */
  	msdp = &nvchan->msd;
  	if (msdp->pkt)
  		msd_len = msdp->pkt->total_data_buflen;
  
  	try_batch =  msd_len > 0 && msdp->count < net_device->max_pkt;
  	if (try_batch && msd_len + pktlen + net_device->pkt_align <
  	    net_device->send_section_size) {
  		section_index = msdp->pkt->send_buf_index;
  
  	} else if (try_batch && msd_len + packet->rmsg_size <
  		   net_device->send_section_size) {
  		section_index = msdp->pkt->send_buf_index;
  		packet->cp_partial = true;
  
  	} else if (pktlen + net_device->pkt_align <
  		   net_device->send_section_size) {
  		section_index = netvsc_get_next_send_section(net_device);
  		if (section_index != NETVSC_INVALID_INDEX) {
  			move_pkt_msd(&msd_send, &msd_skb, msdp);
  			msd_len = 0;
  		}
  	}
  
  	if (section_index != NETVSC_INVALID_INDEX) {
  		netvsc_copy_to_send_buf(net_device,
  					section_index, msd_len,
  					packet, rndis_msg, pb, skb);
  
  		packet->send_buf_index = section_index;
  
  		if (packet->cp_partial) {
  			packet->page_buf_cnt -= packet->rmsg_pgcnt;
  			packet->total_data_buflen = msd_len + packet->rmsg_size;
  		} else {
  			packet->page_buf_cnt = 0;
  			packet->total_data_buflen += msd_len;
  		}
  
  		if (msdp->pkt) {
  			packet->total_packets += msdp->pkt->total_packets;
  			packet->total_bytes += msdp->pkt->total_bytes;
  		}
  
  		if (msdp->skb)
  			dev_consume_skb_any(msdp->skb);
  
  		if (xmit_more && !packet->cp_partial) {
  			msdp->skb = skb;
  			msdp->pkt = packet;
  			msdp->count++;
  		} else {
  			cur_send = packet;
  			msdp->skb = NULL;
  			msdp->pkt = NULL;
  			msdp->count = 0;
  		}
  	} else {
  		move_pkt_msd(&msd_send, &msd_skb, msdp);
  		cur_send = packet;
  	}
  
  	if (msd_send) {
  		int m_ret = netvsc_send_pkt(device, msd_send, net_device,
  					    NULL, msd_skb);
  
  		if (m_ret != 0) {
  			netvsc_free_send_slot(net_device,
  					      msd_send->send_buf_index);
  			dev_kfree_skb_any(msd_skb);
  		}
  	}
  
  send_now:
  	if (cur_send)
  		ret = netvsc_send_pkt(device, cur_send, net_device, pb, skb);
  
  	if (ret != 0 && section_index != NETVSC_INVALID_INDEX)
  		netvsc_free_send_slot(net_device, section_index);
  
  	return ret;
  }
  
  static int netvsc_send_recv_completion(struct vmbus_channel *channel,
  				       u64 transaction_id, u32 status)
  {
  	struct nvsp_message recvcompMessage;
  	int ret;
  
  	recvcompMessage.hdr.msg_type =
  				NVSP_MSG1_TYPE_SEND_RNDIS_PKT_COMPLETE;
  
  	recvcompMessage.msg.v1_msg.send_rndis_pkt_complete.status = status;
  
  	/* Send the completion */
  	ret = vmbus_sendpacket(channel, &recvcompMessage,
  			       sizeof(struct nvsp_message_header) + sizeof(u32),
  			       transaction_id, VM_PKT_COMP, 0);
  
  	return ret;
  }
  
  static inline void count_recv_comp_slot(struct netvsc_device *nvdev, u16 q_idx,
  					u32 *filled, u32 *avail)
  {
  	struct multi_recv_comp *mrc = &nvdev->chan_table[q_idx].mrc;
  	u32 first = mrc->first;
  	u32 next = mrc->next;
  
  	*filled = (first > next) ? NETVSC_RECVSLOT_MAX - first + next :
  		  next - first;
  
  	*avail = NETVSC_RECVSLOT_MAX - *filled - 1;
  }
  
  /* Read the first filled slot, no change to index */
  static inline struct recv_comp_data *read_recv_comp_slot(struct netvsc_device
  							 *nvdev, u16 q_idx)
  {
  	struct multi_recv_comp *mrc = &nvdev->chan_table[q_idx].mrc;
  	u32 filled, avail;
  
  	if (unlikely(!mrc->buf))
  		return NULL;
  
  	count_recv_comp_slot(nvdev, q_idx, &filled, &avail);
  	if (!filled)
  		return NULL;
  
  	return mrc->buf + mrc->first * sizeof(struct recv_comp_data);
  }
  
  /* Put the first filled slot back to available pool */
  static inline void put_recv_comp_slot(struct netvsc_device *nvdev, u16 q_idx)
  {
  	struct multi_recv_comp *mrc = &nvdev->chan_table[q_idx].mrc;
  	int num_recv;
  
  	mrc->first = (mrc->first + 1) % NETVSC_RECVSLOT_MAX;
  
  	num_recv = atomic_dec_return(&nvdev->num_outstanding_recvs);
  
  	if (nvdev->destroy && num_recv == 0)
  		wake_up(&nvdev->wait_drain);
  }
  
  /* Check and send pending recv completions */
  static void netvsc_chk_recv_comp(struct netvsc_device *nvdev,
  				 struct vmbus_channel *channel, u16 q_idx)
  {
  	struct recv_comp_data *rcd;
  	int ret;
  
  	while (true) {
  		rcd = read_recv_comp_slot(nvdev, q_idx);
  		if (!rcd)
  			break;
  
  		ret = netvsc_send_recv_completion(channel, rcd->tid,
  						  rcd->status);
  		if (ret)
  			break;
  
  		put_recv_comp_slot(nvdev, q_idx);
  	}
  }
  
  #define NETVSC_RCD_WATERMARK 80
  
  /* Get next available slot */
  static inline struct recv_comp_data *get_recv_comp_slot(
  	struct netvsc_device *nvdev, struct vmbus_channel *channel, u16 q_idx)
  {
  	struct multi_recv_comp *mrc = &nvdev->chan_table[q_idx].mrc;
  	u32 filled, avail, next;
  	struct recv_comp_data *rcd;
  
  	if (unlikely(!nvdev->recv_section))
  		return NULL;
  
  	if (unlikely(!mrc->buf))
  		return NULL;
  
  	if (atomic_read(&nvdev->num_outstanding_recvs) >
  	    nvdev->recv_section->num_sub_allocs * NETVSC_RCD_WATERMARK / 100)
  		netvsc_chk_recv_comp(nvdev, channel, q_idx);
  
  	count_recv_comp_slot(nvdev, q_idx, &filled, &avail);
  	if (!avail)
  		return NULL;
  
  	next = mrc->next;
  	rcd = mrc->buf + next * sizeof(struct recv_comp_data);
  	mrc->next = (next + 1) % NETVSC_RECVSLOT_MAX;
  
  	atomic_inc(&nvdev->num_outstanding_recvs);
  
  	return rcd;
  }
  
  static int netvsc_receive(struct net_device *ndev,
  		   struct netvsc_device *net_device,
  		   struct net_device_context *net_device_ctx,
  		   struct hv_device *device,
  		   struct vmbus_channel *channel,
  		   const struct vmpacket_descriptor *desc,
  		   struct nvsp_message *nvsp)
  {
  	const struct vmtransfer_page_packet_header *vmxferpage_packet
  		= container_of(desc, const struct vmtransfer_page_packet_header, d);
  	u16 q_idx = channel->offermsg.offer.sub_channel_index;
  	char *recv_buf = net_device->recv_buf;
  	u32 status = NVSP_STAT_SUCCESS;
  	int i;
  	int count = 0;
  	int ret;
  
  	/* Make sure this is a valid nvsp packet */
  	if (unlikely(nvsp->hdr.msg_type != NVSP_MSG1_TYPE_SEND_RNDIS_PKT)) {
  		netif_err(net_device_ctx, rx_err, ndev,
  			  "Unknown nvsp packet type received %u\n",
  			  nvsp->hdr.msg_type);
  		return 0;
  	}
  
  	if (unlikely(vmxferpage_packet->xfer_pageset_id != NETVSC_RECEIVE_BUFFER_ID)) {
  		netif_err(net_device_ctx, rx_err, ndev,
  			  "Invalid xfer page set id - expecting %x got %x\n",
  			  NETVSC_RECEIVE_BUFFER_ID,
  			  vmxferpage_packet->xfer_pageset_id);
  		return 0;
  	}
  
  	count = vmxferpage_packet->range_cnt;
  
  	/* Each range represents 1 RNDIS pkt that contains 1 ethernet frame */
  	for (i = 0; i < count; i++) {
  		void *data = recv_buf
  			+ vmxferpage_packet->ranges[i].byte_offset;
  		u32 buflen = vmxferpage_packet->ranges[i].byte_count;
  
  		/* Pass it to the upper layer */
  		status = rndis_filter_receive(ndev, net_device, device,
  					      channel, data, buflen);
  	}
  
  	if (net_device->chan_table[q_idx].mrc.buf) {
  		struct recv_comp_data *rcd;
  
  		rcd = get_recv_comp_slot(net_device, channel, q_idx);
  		if (rcd) {
  			rcd->tid = vmxferpage_packet->d.trans_id;
  			rcd->status = status;
  		} else {
  			netdev_err(ndev, "Recv_comp full buf q:%hd, tid:%llx\n",
  				   q_idx, vmxferpage_packet->d.trans_id);
  		}
  	} else {
  		ret = netvsc_send_recv_completion(channel,
  						  vmxferpage_packet->d.trans_id,
  						  status);
  		if (ret)
  			netdev_err(ndev, "Recv_comp q:%hd, tid:%llx, err:%d\n",
  				   q_idx, vmxferpage_packet->d.trans_id, ret);
  	}
  	return count;
  }
  
  static void netvsc_send_table(struct hv_device *hdev,
  			      struct nvsp_message *nvmsg)
  {
  	struct net_device *ndev = hv_get_drvdata(hdev);
  	struct net_device_context *net_device_ctx = netdev_priv(ndev);
  	int i;
  	u32 count, *tab;
  
  	count = nvmsg->msg.v5_msg.send_table.count;
  	if (count != VRSS_SEND_TAB_SIZE) {
  		netdev_err(ndev, "Received wrong send-table size:%u\n", count);
  		return;
  	}
  
  	tab = (u32 *)((unsigned long)&nvmsg->msg.v5_msg.send_table +
  		      nvmsg->msg.v5_msg.send_table.offset);
  
  	for (i = 0; i < count; i++)
  		net_device_ctx->tx_send_table[i] = tab[i];
  }
  
  static void netvsc_send_vf(struct net_device_context *net_device_ctx,
  			   struct nvsp_message *nvmsg)
  {
  	net_device_ctx->vf_alloc = nvmsg->msg.v4_msg.vf_assoc.allocated;
  	net_device_ctx->vf_serial = nvmsg->msg.v4_msg.vf_assoc.serial;
  }
  
  static inline void netvsc_receive_inband(struct hv_device *hdev,
  				 struct net_device_context *net_device_ctx,
  				 struct nvsp_message *nvmsg)
  {
  	switch (nvmsg->hdr.msg_type) {
  	case NVSP_MSG5_TYPE_SEND_INDIRECTION_TABLE:
  		netvsc_send_table(hdev, nvmsg);
  		break;
  
  	case NVSP_MSG4_TYPE_SEND_VF_ASSOCIATION:
  		netvsc_send_vf(net_device_ctx, nvmsg);
  		break;
  	}
  }
  
  static int netvsc_process_raw_pkt(struct hv_device *device,
  				  struct vmbus_channel *channel,
  				  struct netvsc_device *net_device,
  				  struct net_device *ndev,
  				  const struct vmpacket_descriptor *desc,
  				  int budget)
  {
  	struct net_device_context *net_device_ctx = netdev_priv(ndev);
  	struct nvsp_message *nvmsg = hv_pkt_data(desc);
  
  	switch (desc->type) {
  	case VM_PKT_COMP:
  		netvsc_send_completion(net_device, channel, device,
  				       desc, budget);
  		break;
  
  	case VM_PKT_DATA_USING_XFER_PAGES:
  		return netvsc_receive(ndev, net_device, net_device_ctx,
  				      device, channel, desc, nvmsg);
  		break;
  
  	case VM_PKT_DATA_INBAND:
  		netvsc_receive_inband(device, net_device_ctx, nvmsg);
  		break;
  
  	default:
  		netdev_err(ndev, "unhandled packet type %d, tid %llx\n",
  			   desc->type, desc->trans_id);
  		break;
  	}
  
  	return 0;
  }
  
  static struct hv_device *netvsc_channel_to_device(struct vmbus_channel *channel)
  {
  	struct vmbus_channel *primary = channel->primary_channel;
  
  	return primary ? primary->device_obj : channel->device_obj;
  }
  
  /* Network processing softirq
   * Process data in incoming ring buffer from host
   * Stops when ring is empty or budget is met or exceeded.
   */
  int netvsc_poll(struct napi_struct *napi, int budget)
  {
  	struct netvsc_channel *nvchan
  		= container_of(napi, struct netvsc_channel, napi);
  	struct vmbus_channel *channel = nvchan->channel;
  	struct hv_device *device = netvsc_channel_to_device(channel);
  	u16 q_idx = channel->offermsg.offer.sub_channel_index;
  	struct net_device *ndev = hv_get_drvdata(device);
  	struct netvsc_device *net_device = net_device_to_netvsc_device(ndev);
  	int work_done = 0;
  
  	/* If starting a new interval */
  	if (!nvchan->desc)
  		nvchan->desc = hv_pkt_iter_first(channel);
  
  	while (nvchan->desc && work_done < budget) {
  		work_done += netvsc_process_raw_pkt(device, channel, net_device,
  						    ndev, nvchan->desc, budget);
  		nvchan->desc = hv_pkt_iter_next(channel, nvchan->desc);
  	}
  
  	/* If receive ring was exhausted
  	 * and not doing busy poll
  	 * then re-enable host interrupts
  	 *  and reschedule if ring is not empty.
  	 */
  	if (work_done < budget &&
  	    napi_complete_done(napi, work_done) &&
  	    hv_end_read(&channel->inbound) != 0)
  		napi_reschedule(napi);
  
  	netvsc_chk_recv_comp(net_device, channel, q_idx);
  
  	/* Driver may overshoot since multiple packets per descriptor */
  	return min(work_done, budget);
  }
  
  /* Call back when data is available in host ring buffer.
   * Processing is deferred until network softirq (NAPI)
   */
  void netvsc_channel_cb(void *context)
  {
  	struct netvsc_channel *nvchan = context;
  
  	if (napi_schedule_prep(&nvchan->napi)) {
  		/* disable interupts from host */
  		hv_begin_read(&nvchan->channel->inbound);
  
  		__napi_schedule(&nvchan->napi);
  	}
  }
  
  /*
   * netvsc_device_add - Callback when the device belonging to this
   * driver is added
   */
  int netvsc_device_add(struct hv_device *device,
  		      const struct netvsc_device_info *device_info)
  {
  	int i, ret = 0;
  	int ring_size = device_info->ring_size;
  	struct netvsc_device *net_device;
  	struct net_device *ndev = hv_get_drvdata(device);
  	struct net_device_context *net_device_ctx = netdev_priv(ndev);
  
  	net_device = alloc_net_device();
  	if (!net_device)
  		return -ENOMEM;
  
  	net_device->ring_size = ring_size;
  
  	/* Because the device uses NAPI, all the interrupt batching and
  	 * control is done via Net softirq, not the channel handling
  	 */
  	set_channel_read_mode(device->channel, HV_CALL_ISR);
  
  	/* If we're reopening the device we may have multiple queues, fill the
  	 * chn_table with the default channel to use it before subchannels are
  	 * opened.
  	 * Initialize the channel state before we open;
  	 * we can be interrupted as soon as we open the channel.
  	 */
  
  	for (i = 0; i < VRSS_CHANNEL_MAX; i++) {
  		struct netvsc_channel *nvchan = &net_device->chan_table[i];
  
  		nvchan->channel = device->channel;
  		u64_stats_init(&nvchan->tx_stats.syncp);
  		u64_stats_init(&nvchan->rx_stats.syncp);
  	}
  
  	/* Enable NAPI handler before init callbacks */
  	netif_napi_add(ndev, &net_device->chan_table[0].napi,
  		       netvsc_poll, NAPI_POLL_WEIGHT);
  
  	/* Open the channel */
  	ret = vmbus_open(device->channel, ring_size * PAGE_SIZE,
  			 ring_size * PAGE_SIZE, NULL, 0,
  			 netvsc_channel_cb,
  			 net_device->chan_table);
  
  	if (ret != 0) {
  		netif_napi_del(&net_device->chan_table[0].napi);
  		netdev_err(ndev, "unable to open channel: %d\n", ret);
  		goto cleanup;
  	}
  
  	/* Channel is opened */
  	netdev_dbg(ndev, "hv_netvsc channel opened successfully\n");
  
  	napi_enable(&net_device->chan_table[0].napi);
  
  	/* Writing nvdev pointer unlocks netvsc_send(), make sure chn_table is
  	 * populated.
  	 */
  	rcu_assign_pointer(net_device_ctx->nvdev, net_device);
  
  	/* Connect with the NetVsp */
  	ret = netvsc_connect_vsp(device, net_device);
  	if (ret != 0) {
  		netdev_err(ndev,
  			"unable to connect to NetVSP - %d\n", ret);
  		goto close;
  	}
  
  	return ret;
  
  close:
  	netif_napi_del(&net_device->chan_table[0].napi);
  
  	/* Now, we can close the channel safely */
  	vmbus_close(device->channel);
  
  cleanup:
  	free_netvsc_device(&net_device->rcu);
  
  	return ret;
  
  }
  