staging: hv: Remove NULL check before kfree

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / staging / hv / channel_mgmt.c

/*
 * 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>
 */
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/completion.h>
#include "hv_api.h"
#include "logging.h"
#include "vmbus_private.h"
#include "utils.h"

struct vmbus_channel_message_table_entry {
        enum vmbus_channel_message_type messageType;
        void (*messageHandler)(struct vmbus_channel_message_header *msg);
};

#define MAX_MSG_TYPES                    4
#define MAX_NUM_DEVICE_CLASSES_SUPPORTED 8

static const struct hv_guid
        gSupportedDeviceClasses[MAX_NUM_DEVICE_CLASSES_SUPPORTED] = {
        /* {ba6163d9-04a1-4d29-b605-72e2ffb1dc7f} */
        /* Storage - SCSI */
        {
                .data  = {
                        0xd9, 0x63, 0x61, 0xba, 0xa1, 0x04, 0x29, 0x4d,
                        0xb6, 0x05, 0x72, 0xe2, 0xff, 0xb1, 0xdc, 0x7f
                }
        },

        /* {F8615163-DF3E-46c5-913F-F2D2F965ED0E} */
        /* Network */
        {
                .data = {
                        0x63, 0x51, 0x61, 0xF8, 0x3E, 0xDF, 0xc5, 0x46,
                        0x91, 0x3F, 0xF2, 0xD2, 0xF9, 0x65, 0xED, 0x0E
                }
        },

        /* {CFA8B69E-5B4A-4cc0-B98B-8BA1A1F3F95A} */
        /* Input */
        {
                .data = {
                        0x9E, 0xB6, 0xA8, 0xCF, 0x4A, 0x5B, 0xc0, 0x4c,
                        0xB9, 0x8B, 0x8B, 0xA1, 0xA1, 0xF3, 0xF9, 0x5A
                }
        },

        /* {32412632-86cb-44a2-9b5c-50d1417354f5} */
        /* IDE */
        {
                .data = {
                        0x32, 0x26, 0x41, 0x32, 0xcb, 0x86, 0xa2, 0x44,
                        0x9b, 0x5c, 0x50, 0xd1, 0x41, 0x73, 0x54, 0xf5
                }
        },
        /* 0E0B6031-5213-4934-818B-38D90CED39DB */
        /* Shutdown */
        {
                .data = {
                        0x31, 0x60, 0x0B, 0X0E, 0x13, 0x52, 0x34, 0x49,
                        0x81, 0x8B, 0x38, 0XD9, 0x0C, 0xED, 0x39, 0xDB
                }
        },
        /* {9527E630-D0AE-497b-ADCE-E80AB0175CAF} */
        /* TimeSync */
        {
                .data = {
                        0x30, 0xe6, 0x27, 0x95, 0xae, 0xd0, 0x7b, 0x49,
                        0xad, 0xce, 0xe8, 0x0a, 0xb0, 0x17, 0x5c, 0xaf
                }
        },
        /* {57164f39-9115-4e78-ab55-382f3bd5422d} */
        /* Heartbeat */
        {
                .data = {
                        0x39, 0x4f, 0x16, 0x57, 0x15, 0x91, 0x78, 0x4e,
                        0xab, 0x55, 0x38, 0x2f, 0x3b, 0xd5, 0x42, 0x2d
                }
        },
        /* {A9A0F4E7-5A45-4d96-B827-8A841E8C03E6} */
        /* KVP */
        {
                .data = {
                        0xe7, 0xf4, 0xa0, 0xa9, 0x45, 0x5a, 0x96, 0x4d,
                        0xb8, 0x27, 0x8a, 0x84, 0x1e, 0x8c, 0x3,  0xe6
        }
        },

};


/**
 * prep_negotiate_resp() - Create default response for Hyper-V Negotiate message
 * @icmsghdrp: Pointer to msg header structure
 * @icmsg_negotiate: Pointer to negotiate message structure
 * @buf: Raw buffer channel data
 *
 * @icmsghdrp is of type &struct icmsg_hdr.
 * @negop is of type &struct icmsg_negotiate.
 * Set up and fill in default negotiate response message. This response can
 * come from both the vmbus driver and the hv_utils driver. The current api
 * will respond properly to both Windows 2008 and Windows 2008-R2 operating
 * systems.
 *
 * Mainly used by Hyper-V drivers.
 */
void prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
                             struct icmsg_negotiate *negop,
                             u8 *buf)
{
        if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
                icmsghdrp->icmsgsize = 0x10;

                negop = (struct icmsg_negotiate *)&buf[
                        sizeof(struct vmbuspipe_hdr) +
                        sizeof(struct icmsg_hdr)];

                if (negop->icframe_vercnt == 2 &&
                   negop->icversion_data[1].major == 3) {
                        negop->icversion_data[0].major = 3;
                        negop->icversion_data[0].minor = 0;
                        negop->icversion_data[1].major = 3;
                        negop->icversion_data[1].minor = 0;
                } else {
                        negop->icversion_data[0].major = 1;
                        negop->icversion_data[0].minor = 0;
                        negop->icversion_data[1].major = 1;
                        negop->icversion_data[1].minor = 0;
                }

                negop->icframe_vercnt = 1;
                negop->icmsg_vercnt = 1;
        }
}
EXPORT_SYMBOL(prep_negotiate_resp);

/**
 * chn_cb_negotiate() - Default handler for non IDE/SCSI/NETWORK
 * Hyper-V requests
 * @context: Pointer to argument structure.
 *
 * Set up the default handler for non device driver specific requests
 * from Hyper-V. This stub responds to the default negotiate messages
 * that come in for every non IDE/SCSI/Network request.
 * This behavior is normally overwritten in the hv_utils driver. That
 * driver handles requests like gracefull shutdown, heartbeats etc.
 *
 * Mainly used by Hyper-V drivers.
 */
void chn_cb_negotiate(void *context)
{
        struct vmbus_channel *channel = context;
        u8 *buf;
        u32 buflen, recvlen;
        u64 requestid;

        struct icmsg_hdr *icmsghdrp;
        struct icmsg_negotiate *negop = NULL;

        buflen = PAGE_SIZE;
        buf = kmalloc(buflen, GFP_ATOMIC);

        vmbus_recvpacket(channel, buf, buflen, &recvlen, &requestid);

        if (recvlen > 0) {
                icmsghdrp = (struct icmsg_hdr *)&buf[
                        sizeof(struct vmbuspipe_hdr)];

                prep_negotiate_resp(icmsghdrp, negop, buf);

                icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
                        | ICMSGHDRFLAG_RESPONSE;

                vmbus_sendpacket(channel, buf,
                                       recvlen, requestid,
                                       VM_PKT_DATA_INBAND, 0);
        }

        kfree(buf);
}
EXPORT_SYMBOL(chn_cb_negotiate);

/*
 * Function table used for message responses for non IDE/SCSI/Network type
 * messages. (Such as KVP/Shutdown etc)
 */
struct hyperv_service_callback hv_cb_utils[MAX_MSG_TYPES] = {
        /* 0E0B6031-5213-4934-818B-38D90CED39DB */
        /* Shutdown */
        {
                .msg_type = HV_SHUTDOWN_MSG,
                .data = {
                        0x31, 0x60, 0x0B, 0X0E, 0x13, 0x52, 0x34, 0x49,
                        0x81, 0x8B, 0x38, 0XD9, 0x0C, 0xED, 0x39, 0xDB
                },
                .callback = chn_cb_negotiate,
                .log_msg = "Shutdown channel functionality initialized"
        },

        /* {9527E630-D0AE-497b-ADCE-E80AB0175CAF} */
        /* TimeSync */
        {
                .msg_type = HV_TIMESYNC_MSG,
                .data = {
                        0x30, 0xe6, 0x27, 0x95, 0xae, 0xd0, 0x7b, 0x49,
                        0xad, 0xce, 0xe8, 0x0a, 0xb0, 0x17, 0x5c, 0xaf
                },
                .callback = chn_cb_negotiate,
                .log_msg = "Timesync channel functionality initialized"
        },
        /* {57164f39-9115-4e78-ab55-382f3bd5422d} */
        /* Heartbeat */
        {
                .msg_type = HV_HEARTBEAT_MSG,
                .data = {
                        0x39, 0x4f, 0x16, 0x57, 0x15, 0x91, 0x78, 0x4e,
                        0xab, 0x55, 0x38, 0x2f, 0x3b, 0xd5, 0x42, 0x2d
                },
                .callback = chn_cb_negotiate,
                .log_msg = "Heartbeat channel functionality initialized"
        },
        /* {A9A0F4E7-5A45-4d96-B827-8A841E8C03E6} */
        /* KVP */
        {
                .data = {
                        0xe7, 0xf4, 0xa0, 0xa9, 0x45, 0x5a, 0x96, 0x4d,
                        0xb8, 0x27, 0x8a, 0x84, 0x1e, 0x8c, 0x3,  0xe6
                },
                .callback = chn_cb_negotiate,
                .log_msg = "KVP channel functionality initialized"
        },
};
EXPORT_SYMBOL(hv_cb_utils);

/*
 * alloc_channel - Allocate and initialize a vmbus channel object
 */
static struct vmbus_channel *alloc_channel(void)
{
        struct vmbus_channel *channel;

        channel = kzalloc(sizeof(*channel), GFP_ATOMIC);
        if (!channel)
                return NULL;

        spin_lock_init(&channel->inbound_lock);

        init_timer(&channel->poll_timer);
        channel->poll_timer.data = (unsigned long)channel;
        channel->poll_timer.function = vmbus_ontimer;

        channel->controlwq = create_workqueue("hv_vmbus_ctl");
        if (!channel->controlwq) {
                kfree(channel);
                return NULL;
        }

        return channel;
}

/*
 * release_hannel - Release the vmbus channel object itself
 */
static void release_channel(struct work_struct *work)
{
        struct vmbus_channel *channel = container_of(work,
                                                     struct vmbus_channel,
                                                     work);

        DPRINT_DBG(VMBUS, "releasing channel (%p)", channel);
        destroy_workqueue(channel->controlwq);
        DPRINT_DBG(VMBUS, "channel released (%p)", channel);

        kfree(channel);
}

/*
 * free_channel - Release the resources used by the vmbus channel object
 */
void free_channel(struct vmbus_channel *channel)
{
        del_timer_sync(&channel->poll_timer);

        /*
         * We have to release the channel's workqueue/thread in the vmbus's
         * workqueue/thread context
         * ie we can't destroy ourselves.
         */
        INIT_WORK(&channel->work, release_channel);
        queue_work(vmbus_connection.work_queue, &channel->work);
}


DECLARE_COMPLETION(hv_channel_ready);

/*
 * Count initialized channels, and ensure all channels are ready when hv_vmbus
 * module loading completes.
 */
static void count_hv_channel(void)
{
        static int counter;
        unsigned long flags;

        spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
        if (++counter == MAX_MSG_TYPES)
                complete(&hv_channel_ready);
        spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
}

/*
 * vmbus_process_rescind_offer -
 * Rescind the offer by initiating a device removal
 */
static void vmbus_process_rescind_offer(struct work_struct *work)
{
        struct vmbus_channel *channel = container_of(work,
                                                     struct vmbus_channel,
                                                     work);

        vmbus_child_device_unregister(channel->device_obj);
}

/*
 * vmbus_process_offer - Process the offer by creating a channel/device
 * associated with this offer
 */
static void vmbus_process_offer(struct work_struct *work)
{
        struct vmbus_channel *newchannel = container_of(work,
                                                        struct vmbus_channel,
                                                        work);
        struct vmbus_channel *channel;
        bool fnew = true;
        int ret;
        int cnt;
        unsigned long flags;

        /* The next possible work is rescind handling */
        INIT_WORK(&newchannel->work, vmbus_process_rescind_offer);

        /* Make sure this is a new offer */
        spin_lock_irqsave(&vmbus_connection.channel_lock, flags);

        list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
                if (!memcmp(&channel->offermsg.offer.if_type,
                            &newchannel->offermsg.offer.if_type,
                            sizeof(struct hv_guid)) &&
                    !memcmp(&channel->offermsg.offer.if_instance,
                            &newchannel->offermsg.offer.if_instance,
                            sizeof(struct hv_guid))) {
                        fnew = false;
                        break;
                }
        }

        if (fnew)
                list_add_tail(&newchannel->listentry,
                              &vmbus_connection.chn_list);

        spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);

        if (!fnew) {
                DPRINT_DBG(VMBUS, "Ignoring duplicate offer for relid (%d)",
                           newchannel->offermsg.child_relid);
                free_channel(newchannel);
                return;
        }

        /*
         * Start the process of binding this offer to the driver
         * We need to set the DeviceObject field before calling
         * vmbus_child_dev_add()
         */
        newchannel->device_obj = vmbus_child_device_create(
                &newchannel->offermsg.offer.if_type,
                &newchannel->offermsg.offer.if_instance,
                newchannel);

        DPRINT_DBG(VMBUS, "child device object allocated - %p",
                   newchannel->device_obj);

        /*
         * Add the new device to the bus. This will kick off device-driver
         * binding which eventually invokes the device driver's AddDevice()
         * method.
         */
        ret = vmbus_child_device_register(newchannel->device_obj);
        if (ret != 0) {
                DPRINT_ERR(VMBUS,
                           "unable to add child device object (relid %d)",
                           newchannel->offermsg.child_relid);

                spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
                list_del(&newchannel->listentry);
                spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);

                free_channel(newchannel);
        } else {
                /*
                 * This state is used to indicate a successful open
                 * so that when we do close the channel normally, we
                 * can cleanup properly
                 */
                newchannel->state = CHANNEL_OPEN_STATE;

                /* Open IC channels */
                for (cnt = 0; cnt < MAX_MSG_TYPES; cnt++) {
                        if (memcmp(&newchannel->offermsg.offer.if_type,
                                   &hv_cb_utils[cnt].data,
                                   sizeof(struct hv_guid)) == 0 &&
                                vmbus_open(newchannel, 2 * PAGE_SIZE,
                                                 2 * PAGE_SIZE, NULL, 0,
                                                 hv_cb_utils[cnt].callback,
                                                 newchannel) == 0) {
                                hv_cb_utils[cnt].channel = newchannel;
                                DPRINT_INFO(VMBUS, "%s",
                                                hv_cb_utils[cnt].log_msg);
                                count_hv_channel();
                        }
                }
        }
}

/*
 * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 *
 * We ignore all offers except network and storage offers. For each network and
 * storage offers, we create a channel object and queue a work item to the
 * channel object to process the offer synchronously
 */
static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
{
        struct vmbus_channel_offer_channel *offer;
        struct vmbus_channel *newchannel;
        struct hv_guid *guidtype;
        struct hv_guid *guidinstance;
        int i;
        int fsupported = 0;

        offer = (struct vmbus_channel_offer_channel *)hdr;
        for (i = 0; i < MAX_NUM_DEVICE_CLASSES_SUPPORTED; i++) {
                if (memcmp(&offer->offer.if_type,
                    &gSupportedDeviceClasses[i], sizeof(struct hv_guid)) == 0) {
                        fsupported = 1;
                        break;
                }
        }

        if (!fsupported) {
                DPRINT_DBG(VMBUS, "Ignoring channel offer notification for "
                           "child relid %d", offer->child_relid);
                return;
        }

        guidtype = &offer->offer.if_type;
        guidinstance = &offer->offer.if_instance;

        DPRINT_INFO(VMBUS, "Channel offer notification - "
                    "child relid %d monitor id %d allocated %d, "
                    "type {%02x%02x%02x%02x-%02x%02x-%02x%02x-"
                    "%02x%02x%02x%02x%02x%02x%02x%02x} "
                    "instance {%02x%02x%02x%02x-%02x%02x-%02x%02x-"
                    "%02x%02x%02x%02x%02x%02x%02x%02x}",
                    offer->child_relid, offer->monitorid,
                    offer->monitor_allocated,
                    guidtype->data[3], guidtype->data[2],
                    guidtype->data[1], guidtype->data[0],
                    guidtype->data[5], guidtype->data[4],
                    guidtype->data[7], guidtype->data[6],
                    guidtype->data[8], guidtype->data[9],
                    guidtype->data[10], guidtype->data[11],
                    guidtype->data[12], guidtype->data[13],
                    guidtype->data[14], guidtype->data[15],
                    guidinstance->data[3], guidinstance->data[2],
                    guidinstance->data[1], guidinstance->data[0],
                    guidinstance->data[5], guidinstance->data[4],
                    guidinstance->data[7], guidinstance->data[6],
                    guidinstance->data[8], guidinstance->data[9],
                    guidinstance->data[10], guidinstance->data[11],
                    guidinstance->data[12], guidinstance->data[13],
                    guidinstance->data[14], guidinstance->data[15]);

        /* Allocate the channel object and save this offer. */
        newchannel = alloc_channel();
        if (!newchannel) {
                DPRINT_ERR(VMBUS, "unable to allocate channel object");
                return;
        }

        DPRINT_DBG(VMBUS, "channel object allocated - %p", newchannel);

        memcpy(&newchannel->offermsg, offer,
               sizeof(struct vmbus_channel_offer_channel));
        newchannel->monitor_grp = (u8)offer->monitorid / 32;
        newchannel->monitor_bit = (u8)offer->monitorid % 32;

        /* TODO: Make sure the offer comes from our parent partition */
        INIT_WORK(&newchannel->work, vmbus_process_offer);
        queue_work(newchannel->controlwq, &newchannel->work);
}

/*
 * vmbus_onoffer_rescind - Rescind offer handler.
 *
 * We queue a work item to process this offer synchronously
 */
static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
{
        struct vmbus_channel_rescind_offer *rescind;
        struct vmbus_channel *channel;

        rescind = (struct vmbus_channel_rescind_offer *)hdr;
        channel = relid2channel(rescind->child_relid);
        if (channel == NULL) {
                DPRINT_DBG(VMBUS, "channel not found for relId %d",
                           rescind->child_relid);
                return;
        }

        /* work is initialized for vmbus_process_rescind_offer() from
         * vmbus_process_offer() where the channel got created */
        queue_work(channel->controlwq, &channel->work);
}

/*
 * vmbus_onoffers_delivered -
 * This is invoked when all offers have been delivered.
 *
 * Nothing to do here.
 */
static void vmbus_onoffers_delivered(
                        struct vmbus_channel_message_header *hdr)
{
}

/*
 * vmbus_onopen_result - Open result handler.
 *
 * This is invoked when we received a response to our channel open request.
 * Find the matching request, copy the response and signal the requesting
 * thread.
 */
static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
{
        struct vmbus_channel_open_result *result;
        struct vmbus_channel_msginfo *msginfo;
        struct vmbus_channel_message_header *requestheader;
        struct vmbus_channel_open_channel *openmsg;
        unsigned long flags;

        result = (struct vmbus_channel_open_result *)hdr;
        DPRINT_DBG(VMBUS, "vmbus open result - %d", result->status);

        /*
         * Find the open msg, copy the result and signal/unblock the wait event
         */
        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);

        list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
                                msglistentry) {
                requestheader =
                        (struct vmbus_channel_message_header *)msginfo->msg;

                if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
                        openmsg =
                        (struct vmbus_channel_open_channel *)msginfo->msg;
                        if (openmsg->child_relid == result->child_relid &&
                            openmsg->openid == result->openid) {
                                memcpy(&msginfo->response.open_result,
                                       result,
                                       sizeof(struct vmbus_channel_open_result));
                                msginfo->wait_condition = 1;
                                wake_up(&msginfo->waitevent);
                                break;
                        }
                }
        }
        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
}

/*
 * vmbus_ongpadl_created - GPADL created handler.
 *
 * This is invoked when we received a response to our gpadl create request.
 * Find the matching request, copy the response and signal the requesting
 * thread.
 */
static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
{
        struct vmbus_channel_gpadl_created *gpadlcreated;
        struct vmbus_channel_msginfo *msginfo;
        struct vmbus_channel_message_header *requestheader;
        struct vmbus_channel_gpadl_header *gpadlheader;
        unsigned long flags;

        gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
        DPRINT_DBG(VMBUS, "vmbus gpadl created result - %d",
                   gpadlcreated->creation_status);

        /*
         * Find the establish msg, copy the result and signal/unblock the wait
         * event
         */
        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);

        list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
                                msglistentry) {
                requestheader =
                        (struct vmbus_channel_message_header *)msginfo->msg;

                if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
                        gpadlheader =
                        (struct vmbus_channel_gpadl_header *)requestheader;

                        if ((gpadlcreated->child_relid ==
                             gpadlheader->child_relid) &&
                            (gpadlcreated->gpadl == gpadlheader->gpadl)) {
                                memcpy(&msginfo->response.gpadl_created,
                                       gpadlcreated,
                                       sizeof(struct vmbus_channel_gpadl_created));
                                msginfo->wait_condition = 1;
                                wake_up(&msginfo->waitevent);
                                break;
                        }
                }
        }
        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
}

/*
 * vmbus_ongpadl_torndown - GPADL torndown handler.
 *
 * This is invoked when we received a response to our gpadl teardown request.
 * Find the matching request, copy the response and signal the requesting
 * thread.
 */
static void vmbus_ongpadl_torndown(
                        struct vmbus_channel_message_header *hdr)
{
        struct vmbus_channel_gpadl_torndown *gpadl_torndown;
        struct vmbus_channel_msginfo *msginfo;
        struct vmbus_channel_message_header *requestheader;
        struct vmbus_channel_gpadl_teardown *gpadl_teardown;
        unsigned long flags;

        gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;

        /*
         * Find the open msg, copy the result and signal/unblock the wait event
         */
        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);

        list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
                                msglistentry) {
                requestheader =
                        (struct vmbus_channel_message_header *)msginfo->msg;

                if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
                        gpadl_teardown =
                        (struct vmbus_channel_gpadl_teardown *)requestheader;

                        if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
                                memcpy(&msginfo->response.gpadl_torndown,
                                       gpadl_torndown,
                                       sizeof(struct vmbus_channel_gpadl_torndown));
                                msginfo->wait_condition = 1;
                                wake_up(&msginfo->waitevent);
                                break;
                        }
                }
        }
        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
}

/*
 * vmbus_onversion_response - Version response handler
 *
 * This is invoked when we received a response to our initiate contact request.
 * Find the matching request, copy the response and signal the requesting
 * thread.
 */
static void vmbus_onversion_response(
                struct vmbus_channel_message_header *hdr)
{
        struct vmbus_channel_msginfo *msginfo;
        struct vmbus_channel_message_header *requestheader;
        struct vmbus_channel_initiate_contact *initiate;
        struct vmbus_channel_version_response *version_response;
        unsigned long flags;

        version_response = (struct vmbus_channel_version_response *)hdr;
        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);

        list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
                                msglistentry) {
                requestheader =
                        (struct vmbus_channel_message_header *)msginfo->msg;

                if (requestheader->msgtype ==
                    CHANNELMSG_INITIATE_CONTACT) {
                        initiate =
                        (struct vmbus_channel_initiate_contact *)requestheader;
                        memcpy(&msginfo->response.version_response,
                              version_response,
                              sizeof(struct vmbus_channel_version_response));
                        msginfo->wait_condition = 1;
                        wake_up(&msginfo->waitevent);
                }
        }
        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
}

/* Channel message dispatch table */
static struct vmbus_channel_message_table_entry
        gChannelMessageTable[CHANNELMSG_COUNT] = {
        {CHANNELMSG_INVALID,                    NULL},
        {CHANNELMSG_OFFERCHANNEL,               vmbus_onoffer},
        {CHANNELMSG_RESCIND_CHANNELOFFER,       vmbus_onoffer_rescind},
        {CHANNELMSG_REQUESTOFFERS,              NULL},
        {CHANNELMSG_ALLOFFERS_DELIVERED,        vmbus_onoffers_delivered},
        {CHANNELMSG_OPENCHANNEL,                NULL},
        {CHANNELMSG_OPENCHANNEL_RESULT, vmbus_onopen_result},
        {CHANNELMSG_CLOSECHANNEL,               NULL},
        {CHANNELMSG_GPADL_HEADER,               NULL},
        {CHANNELMSG_GPADL_BODY,         NULL},
        {CHANNELMSG_GPADL_CREATED,              vmbus_ongpadl_created},
        {CHANNELMSG_GPADL_TEARDOWN,             NULL},
        {CHANNELMSG_GPADL_TORNDOWN,             vmbus_ongpadl_torndown},
        {CHANNELMSG_RELID_RELEASED,             NULL},
        {CHANNELMSG_INITIATE_CONTACT,           NULL},
        {CHANNELMSG_VERSION_RESPONSE,           vmbus_onversion_response},
        {CHANNELMSG_UNLOAD,                     NULL},
};

/*
 * vmbus_onmessage - Handler for channel protocol messages.
 *
 * This is invoked in the vmbus worker thread context.
 */
void vmbus_onmessage(void *context)
{
        struct hv_message *msg = context;
        struct vmbus_channel_message_header *hdr;
        int size;

        hdr = (struct vmbus_channel_message_header *)msg->u.payload;
        size = msg->header.payload_size;

        DPRINT_DBG(VMBUS, "message type %d size %d", hdr->msgtype, size);

        if (hdr->msgtype >= CHANNELMSG_COUNT) {
                DPRINT_ERR(VMBUS,
                           "Received invalid channel message type %d size %d",
                           hdr->msgtype, size);
                print_hex_dump_bytes("", DUMP_PREFIX_NONE,
                                     (unsigned char *)msg->u.payload, size);
                return;
        }

        if (gChannelMessageTable[hdr->msgtype].messageHandler)
                gChannelMessageTable[hdr->msgtype].messageHandler(hdr);
        else
                DPRINT_ERR(VMBUS, "Unhandled channel message type %d",
                           hdr->msgtype);
}

/*
 * vmbus_request_offers - Send a request to get all our pending offers.
 */
int vmbus_request_offers(void)
{
        struct vmbus_channel_message_header *msg;
        struct vmbus_channel_msginfo *msginfo;
        int ret;

        msginfo = kmalloc(sizeof(*msginfo) +
                          sizeof(struct vmbus_channel_message_header),
                          GFP_KERNEL);
        if (!msginfo)
                return -ENOMEM;

        init_waitqueue_head(&msginfo->waitevent);

        msg = (struct vmbus_channel_message_header *)msginfo->msg;

        msg->msgtype = CHANNELMSG_REQUESTOFFERS;


        ret = vmbus_post_msg(msg,
                               sizeof(struct vmbus_channel_message_header));
        if (ret != 0) {
                DPRINT_ERR(VMBUS, "Unable to request offers - %d", ret);

                goto cleanup;
        }

        msginfo->wait_condition = 0;
        wait_event_timeout(msginfo->waitevent, msginfo->wait_condition,
                        msecs_to_jiffies(1000));
        if (msginfo->wait_condition == 0) {
                ret = -ETIMEDOUT;
                goto cleanup;
        }



cleanup:
        kfree(msginfo);

        return ret;
}

/*
 * vmbus_release_unattached_channels - Release channels that are
 * unattached/unconnected ie (no drivers associated)
 */
void vmbus_release_unattached_channels(void)
{
        struct vmbus_channel *channel, *pos;
        struct vmbus_channel *start = NULL;
        unsigned long flags;

        spin_lock_irqsave(&vmbus_connection.channel_lock, flags);

        list_for_each_entry_safe(channel, pos, &vmbus_connection.chn_list,
                                 listentry) {
                if (channel == start)
                        break;

                if (!channel->device_obj->drv) {
                        list_del(&channel->listentry);
                        DPRINT_INFO(VMBUS,
                                    "Releasing unattached device object %p",
                                    channel->device_obj);

                        vmbus_child_device_unregister(channel->device_obj);
                        free_channel(channel);
                } else {
                        if (!start)
                                start = channel;
                }
        }

        spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
}

/* eof */