staging: hv: move hv_netvsc out of staging area

hv_netvsc has been reviewed on netdev mailing list on 6/09/2011.
All recommended changes have been made. We are requesting to move
it out of staging area.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: KY Srinivasan <kys@microsoft.com>
Signed-off-by: Mike Sterling <Mike.Sterling@microsoft.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 939 insertions, 0 deletions

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
new file mode 100644
index 00000000000..28e69a6c74a
--- /dev/null
+++ b/drivers/net/hyperv/netvsc.c
@@ -0,0 +1,939 @@
+/*
+ * Copyright (c) 2009, Microsoft Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * Authors:
+ *   Haiyang Zhang <haiyangz@microsoft.com>
+ *   Hank Janssen  <hjanssen@microsoft.com>
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/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 "hyperv_net.h"
+
+
+static struct netvsc_device *alloc_net_device(struct hv_device *device)
+{
+	struct netvsc_device *net_device;
+	struct net_device *ndev = hv_get_drvdata(device);
+
+	net_device = kzalloc(sizeof(struct netvsc_device), GFP_KERNEL);
+	if (!net_device)
+		return NULL;
+
+
+	net_device->destroy = false;
+	net_device->dev = device;
+	net_device->ndev = ndev;
+
+	hv_set_drvdata(device, net_device);
+	return net_device;
+}
+
+static struct netvsc_device *get_outbound_net_device(struct hv_device *device)
+{
+	struct netvsc_device *net_device;
+
+	net_device = hv_get_drvdata(device);
+	if (net_device && net_device->destroy)
+		net_device = NULL;
+
+	return net_device;
+}
+
+static struct netvsc_device *get_inbound_net_device(struct hv_device *device)
+{
+	struct netvsc_device *net_device;
+
+	net_device = hv_get_drvdata(device);
+
+	if (!net_device)
+		goto get_in_err;
+
+	if (net_device->destroy &&
+		atomic_read(&net_device->num_outstanding_sends) == 0)
+		net_device = NULL;
+
+get_in_err:
+	return net_device;
+}
+
+
+static int netvsc_destroy_recv_buf(struct netvsc_device *net_device)
+{
+	struct nvsp_message *revoke_packet;
+	int ret = 0;
+	struct net_device *ndev = net_device->ndev;
+
+	/*
+	 * 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(net_device->dev->channel,
+				       revoke_packet,
+				       sizeof(struct nvsp_message),
+				       (unsigned long)revoke_packet,
+				       VM_PKT_DATA_INBAND, 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 ret;
+		}
+	}
+
+	/* Teardown the gpadl on the vsp end */
+	if (net_device->recv_buf_gpadl_handle) {
+		ret = vmbus_teardown_gpadl(net_device->dev->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 ret;
+		}
+		net_device->recv_buf_gpadl_handle = 0;
+	}
+
+	if (net_device->recv_buf) {
+		/* Free up the receive buffer */
+		free_pages((unsigned long)net_device->recv_buf,
+			get_order(net_device->recv_buf_size));
+		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;
+	}
+
+	return ret;
+}
+
+static int netvsc_init_recv_buf(struct hv_device *device)
+{
+	int ret = 0;
+	int t;
+	struct netvsc_device *net_device;
+	struct nvsp_message *init_packet;
+	struct net_device *ndev;
+
+	net_device = get_outbound_net_device(device);
+	if (!net_device)
+		return -ENODEV;
+	ndev = net_device->ndev;
+
+	net_device->recv_buf =
+		(void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
+				get_order(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;
+	}
+
+	t = wait_for_completion_timeout(&net_device->channel_init_wait, 5*HZ);
+	BUG_ON(t == 0);
+
+
+	/* 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;
+	}
+
+	goto exit;
+
+cleanup:
+	netvsc_destroy_recv_buf(net_device);
+
+exit:
+	return ret;
+}
+
+
+static int netvsc_connect_vsp(struct hv_device *device)
+{
+	int ret, t;
+	struct netvsc_device *net_device;
+	struct nvsp_message *init_packet;
+	int ndis_version;
+	struct net_device *ndev;
+
+	net_device = get_outbound_net_device(device);
+	if (!net_device)
+		return -ENODEV;
+	ndev = net_device->ndev;
+
+	init_packet = &net_device->channel_init_pkt;
+
+	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_MIN_PROTOCOL_VERSION;
+	init_packet->msg.init_msg.init.max_protocol_ver =
+		NVSP_MAX_PROTOCOL_VERSION;
+
+	/* 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)
+		goto cleanup;
+
+	t = wait_for_completion_timeout(&net_device->channel_init_wait, 5*HZ);
+
+	if (t == 0) {
+		ret = -ETIMEDOUT;
+		goto cleanup;
+	}
+
+	if (init_packet->msg.init_msg.init_complete.status !=
+	    NVSP_STAT_SUCCESS) {
+		ret = -EINVAL;
+		goto cleanup;
+	}
+
+	if (init_packet->msg.init_msg.init_complete.
+	    negotiated_protocol_ver != NVSP_PROTOCOL_VERSION_1) {
+		ret = -EPROTO;
+		goto cleanup;
+	}
+	/* Send the ndis version */
+	memset(init_packet, 0, sizeof(struct nvsp_message));
+
+	ndis_version = 0x00050000;
+
+	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 */
+	ret = netvsc_init_recv_buf(device);
+
+cleanup:
+	return ret;
+}
+
+static void netvsc_disconnect_vsp(struct netvsc_device *net_device)
+{
+	netvsc_destroy_recv_buf(net_device);
+}
+
+/*
+ * netvsc_device_remove - Callback when the root bus device is removed
+ */
+int netvsc_device_remove(struct hv_device *device)
+{
+	struct netvsc_device *net_device;
+	struct hv_netvsc_packet *netvsc_packet, *pos;
+	unsigned long flags;
+
+	net_device = hv_get_drvdata(device);
+	spin_lock_irqsave(&device->channel->inbound_lock, flags);
+	net_device->destroy = true;
+	spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
+
+	/* Wait for all send completions */
+	while (atomic_read(&net_device->num_outstanding_sends)) {
+		dev_info(&device->device,
+			"waiting for %d requests to complete...\n",
+			atomic_read(&net_device->num_outstanding_sends));
+		udelay(100);
+	}
+
+	netvsc_disconnect_vsp(net_device);
+
+	/*
+	 * Since we have already drained, we don't need to busy wait
+	 * as was done in final_release_stor_device()
+	 * Note that we cannot set the ext pointer to NULL until
+	 * we have drained - to drain the outgoing packets, we need to
+	 * allow incoming packets.
+	 */
+
+	spin_lock_irqsave(&device->channel->inbound_lock, flags);
+	hv_set_drvdata(device, NULL);
+	spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
+
+	/*
+	 * At this point, no one should be accessing net_device
+	 * except in here
+	 */
+	dev_notice(&device->device, "net device safe to remove\n");
+
+	/* Now, we can close the channel safely */
+	vmbus_close(device->channel);
+
+	/* Release all resources */
+	list_for_each_entry_safe(netvsc_packet, pos,
+				 &net_device->recv_pkt_list, list_ent) {
+		list_del(&netvsc_packet->list_ent);
+		kfree(netvsc_packet);
+	}
+
+	kfree(net_device);
+	return 0;
+}
+
+static void netvsc_send_completion(struct hv_device *device,
+				   struct vmpacket_descriptor *packet)
+{
+	struct netvsc_device *net_device;
+	struct nvsp_message *nvsp_packet;
+	struct hv_netvsc_packet *nvsc_packet;
+	struct net_device *ndev;
+
+	net_device = get_inbound_net_device(device);
+	if (!net_device)
+		return;
+	ndev = net_device->ndev;
+
+	nvsp_packet = (struct nvsp_message *)((unsigned long)packet +
+			(packet->offset8 << 3));
+
+	if ((nvsp_packet->hdr.msg_type == NVSP_MSG_TYPE_INIT_COMPLETE) ||
+	    (nvsp_packet->hdr.msg_type ==
+	     NVSP_MSG1_TYPE_SEND_RECV_BUF_COMPLETE) ||
+	    (nvsp_packet->hdr.msg_type ==
+	     NVSP_MSG1_TYPE_SEND_SEND_BUF_COMPLETE)) {
+		/* Copy the response back */
+		memcpy(&net_device->channel_init_pkt, nvsp_packet,
+		       sizeof(struct nvsp_message));
+		complete(&net_device->channel_init_wait);
+	} else if (nvsp_packet->hdr.msg_type ==
+		   NVSP_MSG1_TYPE_SEND_RNDIS_PKT_COMPLETE) {
+		/* Get the send context */
+		nvsc_packet = (struct hv_netvsc_packet *)(unsigned long)
+			packet->trans_id;
+
+		/* Notify the layer above us */
+		nvsc_packet->completion.send.send_completion(
+			nvsc_packet->completion.send.send_completion_ctx);
+
+		atomic_dec(&net_device->num_outstanding_sends);
+	} else {
+		netdev_err(ndev, "Unknown send completion packet type- "
+			   "%d received!!\n", nvsp_packet->hdr.msg_type);
+	}
+
+}
+
+int netvsc_send(struct hv_device *device,
+			struct hv_netvsc_packet *packet)
+{
+	struct netvsc_device *net_device;
+	int ret = 0;
+	struct nvsp_message sendMessage;
+	struct net_device *ndev;
+
+	net_device = get_outbound_net_device(device);
+	if (!net_device)
+		return -ENODEV;
+	ndev = net_device->ndev;
+
+	sendMessage.hdr.msg_type = NVSP_MSG1_TYPE_SEND_RNDIS_PKT;
+	if (packet->is_data_pkt) {
+		/* 0 is RMC_DATA; */
+		sendMessage.msg.v1_msg.send_rndis_pkt.channel_type = 0;
+	} else {
+		/* 1 is RMC_CONTROL; */
+		sendMessage.msg.v1_msg.send_rndis_pkt.channel_type = 1;
+	}
+
+	/* Not using send buffer section */
+	sendMessage.msg.v1_msg.send_rndis_pkt.send_buf_section_index =
+		0xFFFFFFFF;
+	sendMessage.msg.v1_msg.send_rndis_pkt.send_buf_section_size = 0;
+
+	if (packet->page_buf_cnt) {
+		ret = vmbus_sendpacket_pagebuffer(device->channel,
+						  packet->page_buf,
+						  packet->page_buf_cnt,
+						  &sendMessage,
+						  sizeof(struct nvsp_message),
+						  (unsigned long)packet);
+	} else {
+		ret = vmbus_sendpacket(device->channel, &sendMessage,
+				sizeof(struct nvsp_message),
+				(unsigned long)packet,
+				VM_PKT_DATA_INBAND,
+				VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+
+	}
+
+	if (ret != 0)
+		netdev_err(ndev, "Unable to send packet %p ret %d\n",
+			   packet, ret);
+	else
+		atomic_inc(&net_device->num_outstanding_sends);
+
+	return ret;
+}
+
+static void netvsc_send_recv_completion(struct hv_device *device,
+					u64 transaction_id)
+{
+	struct nvsp_message recvcompMessage;
+	int retries = 0;
+	int ret;
+	struct net_device *ndev;
+	struct netvsc_device *net_device = hv_get_drvdata(device);
+
+	ndev = net_device->ndev;
+
+	recvcompMessage.hdr.msg_type =
+				NVSP_MSG1_TYPE_SEND_RNDIS_PKT_COMPLETE;
+
+	/* FIXME: Pass in the status */
+	recvcompMessage.msg.v1_msg.send_rndis_pkt_complete.status =
+		NVSP_STAT_SUCCESS;
+
+retry_send_cmplt:
+	/* Send the completion */
+	ret = vmbus_sendpacket(device->channel, &recvcompMessage,
+			       sizeof(struct nvsp_message), transaction_id,
+			       VM_PKT_COMP, 0);
+	if (ret == 0) {
+		/* success */
+		/* no-op */
+	} else if (ret == -EAGAIN) {
+		/* no more room...wait a bit and attempt to retry 3 times */
+		retries++;
+		netdev_err(ndev, "unable to send receive completion pkt"
+			" (tid %llx)...retrying %d\n", transaction_id, retries);
+
+		if (retries < 4) {
+			udelay(100);
+			goto retry_send_cmplt;
+		} else {
+			netdev_err(ndev, "unable to send receive "
+				"completion pkt (tid %llx)...give up retrying\n",
+				transaction_id);
+		}
+	} else {
+		netdev_err(ndev, "unable to send receive "
+			"completion pkt - %llx\n", transaction_id);
+	}
+}
+
+/* Send a receive completion packet to RNDIS device (ie NetVsp) */
+static void netvsc_receive_completion(void *context)
+{
+	struct hv_netvsc_packet *packet = context;
+	struct hv_device *device = (struct hv_device *)packet->device;
+	struct netvsc_device *net_device;
+	u64 transaction_id = 0;
+	bool fsend_receive_comp = false;
+	unsigned long flags;
+	struct net_device *ndev;
+
+	/*
+	 * Even though it seems logical to do a GetOutboundNetDevice() here to
+	 * send out receive completion, we are using GetInboundNetDevice()
+	 * since we may have disable outbound traffic already.
+	 */
+	net_device = get_inbound_net_device(device);
+	if (!net_device)
+		return;
+	ndev = net_device->ndev;
+
+	/* Overloading use of the lock. */
+	spin_lock_irqsave(&net_device->recv_pkt_list_lock, flags);
+
+	packet->xfer_page_pkt->count--;
+
+	/*
+	 * Last one in the line that represent 1 xfer page packet.
+	 * Return the xfer page packet itself to the freelist
+	 */
+	if (packet->xfer_page_pkt->count == 0) {
+		fsend_receive_comp = true;
+		transaction_id = packet->completion.recv.recv_completion_tid;
+		list_add_tail(&packet->xfer_page_pkt->list_ent,
+			      &net_device->recv_pkt_list);
+
+	}
+
+	/* Put the packet back */
+	list_add_tail(&packet->list_ent, &net_device->recv_pkt_list);
+	spin_unlock_irqrestore(&net_device->recv_pkt_list_lock, flags);
+
+	/* Send a receive completion for the xfer page packet */
+	if (fsend_receive_comp)
+		netvsc_send_recv_completion(device, transaction_id);
+
+}
+
+static void netvsc_receive(struct hv_device *device,
+			    struct vmpacket_descriptor *packet)
+{
+	struct netvsc_device *net_device;
+	struct vmtransfer_page_packet_header *vmxferpage_packet;
+	struct nvsp_message *nvsp_packet;
+	struct hv_netvsc_packet *netvsc_packet = NULL;
+	unsigned long start;
+	unsigned long end, end_virtual;
+	/* struct netvsc_driver *netvscDriver; */
+	struct xferpage_packet *xferpage_packet = NULL;
+	int i, j;
+	int count = 0, bytes_remain = 0;
+	unsigned long flags;
+	struct net_device *ndev;
+
+	LIST_HEAD(listHead);
+
+	net_device = get_inbound_net_device(device);
+	if (!net_device)
+		return;
+	ndev = net_device->ndev;
+
+	/*
+	 * All inbound packets other than send completion should be xfer page
+	 * packet
+	 */
+	if (packet->type != VM_PKT_DATA_USING_XFER_PAGES) {
+		netdev_err(ndev, "Unknown packet type received - %d\n",
+			   packet->type);
+		return;
+	}
+
+	nvsp_packet = (struct nvsp_message *)((unsigned long)packet +
+			(packet->offset8 << 3));
+
+	/* Make sure this is a valid nvsp packet */
+	if (nvsp_packet->hdr.msg_type !=
+	    NVSP_MSG1_TYPE_SEND_RNDIS_PKT) {
+		netdev_err(ndev, "Unknown nvsp packet type received-"
+			" %d\n", nvsp_packet->hdr.msg_type);
+		return;
+	}
+
+	vmxferpage_packet = (struct vmtransfer_page_packet_header *)packet;
+
+	if (vmxferpage_packet->xfer_pageset_id != NETVSC_RECEIVE_BUFFER_ID) {
+		netdev_err(ndev, "Invalid xfer page set id - "
+			   "expecting %x got %x\n", NETVSC_RECEIVE_BUFFER_ID,
+			   vmxferpage_packet->xfer_pageset_id);
+		return;
+	}
+
+	/*
+	 * Grab free packets (range count + 1) to represent this xfer
+	 * page packet. +1 to represent the xfer page packet itself.
+	 * We grab it here so that we know exactly how many we can
+	 * fulfil
+	 */
+	spin_lock_irqsave(&net_device->recv_pkt_list_lock, flags);
+	while (!list_empty(&net_device->recv_pkt_list)) {
+		list_move_tail(net_device->recv_pkt_list.next, &listHead);
+		if (++count == vmxferpage_packet->range_cnt + 1)
+			break;
+	}
+	spin_unlock_irqrestore(&net_device->recv_pkt_list_lock, flags);
+
+	/*
+	 * We need at least 2 netvsc pkts (1 to represent the xfer
+	 * page and at least 1 for the range) i.e. we can handled
+	 * some of the xfer page packet ranges...
+	 */
+	if (count < 2) {
+		netdev_err(ndev, "Got only %d netvsc pkt...needed "
+			"%d pkts. Dropping this xfer page packet completely!\n",
+			count, vmxferpage_packet->range_cnt + 1);
+
+		/* Return it to the freelist */
+		spin_lock_irqsave(&net_device->recv_pkt_list_lock, flags);
+		for (i = count; i != 0; i--) {
+			list_move_tail(listHead.next,
+				       &net_device->recv_pkt_list);
+		}
+		spin_unlock_irqrestore(&net_device->recv_pkt_list_lock,
+				       flags);
+
+		netvsc_send_recv_completion(device,
+					    vmxferpage_packet->d.trans_id);
+
+		return;
+	}
+
+	/* Remove the 1st packet to represent the xfer page packet itself */
+	xferpage_packet = (struct xferpage_packet *)listHead.next;
+	list_del(&xferpage_packet->list_ent);
+
+	/* This is how much we can satisfy */
+	xferpage_packet->count = count - 1;
+
+	if (xferpage_packet->count != vmxferpage_packet->range_cnt) {
+		netdev_err(ndev, "Needed %d netvsc pkts to satisfy "
+			"this xfer page...got %d\n",
+			vmxferpage_packet->range_cnt, xferpage_packet->count);
+	}
+
+	/* Each range represents 1 RNDIS pkt that contains 1 ethernet frame */
+	for (i = 0; i < (count - 1); i++) {
+		netvsc_packet = (struct hv_netvsc_packet *)listHead.next;
+		list_del(&netvsc_packet->list_ent);
+
+		/* Initialize the netvsc packet */
+		netvsc_packet->xfer_page_pkt = xferpage_packet;
+		netvsc_packet->completion.recv.recv_completion =
+					netvsc_receive_completion;
+		netvsc_packet->completion.recv.recv_completion_ctx =
+					netvsc_packet;
+		netvsc_packet->device = device;
+		/* Save this so that we can send it back */
+		netvsc_packet->completion.recv.recv_completion_tid =
+					vmxferpage_packet->d.trans_id;
+
+		netvsc_packet->total_data_buflen =
+					vmxferpage_packet->ranges[i].byte_count;
+		netvsc_packet->page_buf_cnt = 1;
+
+		netvsc_packet->page_buf[0].len =
+					vmxferpage_packet->ranges[i].byte_count;
+
+		start = virt_to_phys((void *)((unsigned long)net_device->
+		recv_buf + vmxferpage_packet->ranges[i].byte_offset));
+
+		netvsc_packet->page_buf[0].pfn = start >> PAGE_SHIFT;
+		end_virtual = (unsigned long)net_device->recv_buf
+		    + vmxferpage_packet->ranges[i].byte_offset
+		    + vmxferpage_packet->ranges[i].byte_count - 1;
+		end = virt_to_phys((void *)end_virtual);
+
+		/* Calculate the page relative offset */
+		netvsc_packet->page_buf[0].offset =
+			vmxferpage_packet->ranges[i].byte_offset &
+			(PAGE_SIZE - 1);
+		if ((end >> PAGE_SHIFT) != (start >> PAGE_SHIFT)) {
+			/* Handle frame across multiple pages: */
+			netvsc_packet->page_buf[0].len =
+				(netvsc_packet->page_buf[0].pfn <<
+				 PAGE_SHIFT)
+				+ PAGE_SIZE - start;
+			bytes_remain = netvsc_packet->total_data_buflen -
+					netvsc_packet->page_buf[0].len;
+			for (j = 1; j < NETVSC_PACKET_MAXPAGE; j++) {
+				netvsc_packet->page_buf[j].offset = 0;
+				if (bytes_remain <= PAGE_SIZE) {
+					netvsc_packet->page_buf[j].len =
+						bytes_remain;
+					bytes_remain = 0;
+				} else {
+					netvsc_packet->page_buf[j].len =
+						PAGE_SIZE;
+					bytes_remain -= PAGE_SIZE;
+				}
+				netvsc_packet->page_buf[j].pfn =
+				    virt_to_phys((void *)(end_virtual -
+						bytes_remain)) >> PAGE_SHIFT;
+				netvsc_packet->page_buf_cnt++;
+				if (bytes_remain == 0)
+					break;
+			}
+		}
+
+		/* Pass it to the upper layer */
+		rndis_filter_receive(device, netvsc_packet);
+
+		netvsc_receive_completion(netvsc_packet->
+				completion.recv.recv_completion_ctx);
+	}
+
+}
+
+static void netvsc_channel_cb(void *context)
+{
+	int ret;
+	struct hv_device *device = context;
+	struct netvsc_device *net_device;
+	u32 bytes_recvd;
+	u64 request_id;
+	unsigned char *packet;
+	struct vmpacket_descriptor *desc;
+	unsigned char *buffer;
+	int bufferlen = NETVSC_PACKET_SIZE;
+	struct net_device *ndev;
+
+	packet = kzalloc(NETVSC_PACKET_SIZE * sizeof(unsigned char),
+			 GFP_ATOMIC);
+	if (!packet)
+		return;
+	buffer = packet;
+
+	net_device = get_inbound_net_device(device);
+	if (!net_device)
+		goto out;
+	ndev = net_device->ndev;
+
+	do {
+		ret = vmbus_recvpacket_raw(device->channel, buffer, bufferlen,
+					   &bytes_recvd, &request_id);
+		if (ret == 0) {
+			if (bytes_recvd > 0) {
+				desc = (struct vmpacket_descriptor *)buffer;
+				switch (desc->type) {
+				case VM_PKT_COMP:
+					netvsc_send_completion(device, desc);
+					break;
+
+				case VM_PKT_DATA_USING_XFER_PAGES:
+					netvsc_receive(device, desc);
+					break;
+
+				default:
+					netdev_err(ndev,
+						   "unhandled packet type %d, "
+						   "tid %llx len %d\n",
+						   desc->type, request_id,
+						   bytes_recvd);
+					break;
+				}
+
+				/* reset */
+				if (bufferlen > NETVSC_PACKET_SIZE) {
+					kfree(buffer);
+					buffer = packet;
+					bufferlen = NETVSC_PACKET_SIZE;
+				}
+			} else {
+				/* reset */
+				if (bufferlen > NETVSC_PACKET_SIZE) {
+					kfree(buffer);
+					buffer = packet;
+					bufferlen = NETVSC_PACKET_SIZE;
+				}
+
+				break;
+			}
+		} else if (ret == -ENOBUFS) {
+			/* Handle large packet */
+			buffer = kmalloc(bytes_recvd, GFP_ATOMIC);
+			if (buffer == NULL) {
+				/* Try again next time around */
+				netdev_err(ndev,
+					   "unable to allocate buffer of size "
+					   "(%d)!!\n", bytes_recvd);
+				break;
+			}
+
+			bufferlen = bytes_recvd;
+		}
+	} while (1);
+
+out:
+	kfree(buffer);
+	return;
+}
+
+/*
+ * netvsc_device_add - Callback when the device belonging to this
+ * driver is added
+ */
+int netvsc_device_add(struct hv_device *device, void *additional_info)
+{
+	int ret = 0;
+	int i;
+	int ring_size =
+	((struct netvsc_device_info *)additional_info)->ring_size;
+	struct netvsc_device *net_device;
+	struct hv_netvsc_packet *packet, *pos;
+	struct net_device *ndev;
+
+	net_device = alloc_net_device(device);
+	if (!net_device) {
+		ret = -ENOMEM;
+		goto cleanup;
+	}
+
+	/*
+	 * Coming into this function, struct net_device * is
+	 * registered as the driver private data.
+	 * In alloc_net_device(), we register struct netvsc_device *
+	 * as the driver private data and stash away struct net_device *
+	 * in struct netvsc_device *.
+	 */
+	ndev = net_device->ndev;
+
+	/* Initialize the NetVSC channel extension */
+	net_device->recv_buf_size = NETVSC_RECEIVE_BUFFER_SIZE;
+	spin_lock_init(&net_device->recv_pkt_list_lock);
+
+	INIT_LIST_HEAD(&net_device->recv_pkt_list);
+
+	for (i = 0; i < NETVSC_RECEIVE_PACKETLIST_COUNT; i++) {
+		packet = kzalloc(sizeof(struct hv_netvsc_packet) +
+				 (NETVSC_RECEIVE_SG_COUNT *
+				  sizeof(struct hv_page_buffer)), GFP_KERNEL);
+		if (!packet)
+			break;
+
+		list_add_tail(&packet->list_ent,
+			      &net_device->recv_pkt_list);
+	}
+	init_completion(&net_device->channel_init_wait);
+
+	/* Open the channel */
+	ret = vmbus_open(device->channel, ring_size * PAGE_SIZE,
+			 ring_size * PAGE_SIZE, NULL, 0,
+			 netvsc_channel_cb, device);
+
+	if (ret != 0) {
+		netdev_err(ndev, "unable to open channel: %d\n", ret);
+		goto cleanup;
+	}
+
+	/* Channel is opened */
+	pr_info("hv_netvsc channel opened successfully\n");
+
+	/* Connect with the NetVsp */
+	ret = netvsc_connect_vsp(device);
+	if (ret != 0) {
+		netdev_err(ndev,
+			"unable to connect to NetVSP - %d\n", ret);
+		goto close;
+	}
+
+	return ret;
+
+close:
+	/* Now, we can close the channel safely */
+	vmbus_close(device->channel);
+
+cleanup:
+
+	if (net_device) {
+		list_for_each_entry_safe(packet, pos,
+					 &net_device->recv_pkt_list,
+					 list_ent) {
+			list_del(&packet->list_ent);
+			kfree(packet);
+		}
+
+		kfree(net_device);
+	}
+
+	return ret;
+}