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 000000000000..28e69a6c74a1
--- /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;
+}