thp: clear_copy_huge_page

[linux/fpc-iii.git] / drivers / staging / hv / channel.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/mm.h>
#include <linux/slab.h>
#include <linux/module.h>
#include "osd.h"
#include "logging.h"
#include "vmbus_private.h"

/* Internal routines */
static int create_gpadl_header(
        void *kbuffer,  /* must be phys and virt contiguous */
        u32 size,       /* page-size multiple */
        struct vmbus_channel_msginfo **msginfo,
        u32 *messagecount);
static void dump_vmbus_channel(struct vmbus_channel *channel);
static void vmbus_setevent(struct vmbus_channel *channel);


#if 0
static void DumpMonitorPage(struct hv_monitor_page *MonitorPage)
{
        int i = 0;
        int j = 0;

        DPRINT_DBG(VMBUS, "monitorPage - %p, trigger state - %d",
                   MonitorPage, MonitorPage->trigger_state);

        for (i = 0; i < 4; i++)
                DPRINT_DBG(VMBUS, "trigger group (%d) - %llx", i,
                           MonitorPage->trigger_group[i].as_uint64);

        for (i = 0; i < 4; i++) {
                for (j = 0; j < 32; j++) {
                        DPRINT_DBG(VMBUS, "latency (%d)(%d) - %llx", i, j,
                                   MonitorPage->latency[i][j]);
                }
        }
        for (i = 0; i < 4; i++) {
                for (j = 0; j < 32; j++) {
                        DPRINT_DBG(VMBUS, "param-conn id (%d)(%d) - %d", i, j,
                               MonitorPage->parameter[i][j].connectionid.asu32);
                        DPRINT_DBG(VMBUS, "param-flag (%d)(%d) - %d", i, j,
                                MonitorPage->parameter[i][j].flag_number);
                }
        }
}
#endif

/*
 * vmbus_setevent- Trigger an event notification on the specified
 * channel.
 */
static void vmbus_setevent(struct vmbus_channel *channel)
{
        struct hv_monitor_page *monitorpage;

        if (channel->offermsg.monitor_allocated) {
                /* Each u32 represents 32 channels */
                set_bit(channel->offermsg.child_relid & 31,
                        (unsigned long *) gVmbusConnection.SendInterruptPage +
                        (channel->offermsg.child_relid >> 5));

                monitorpage = gVmbusConnection.MonitorPages;
                monitorpage++; /* Get the child to parent monitor page */

                set_bit(channel->monitor_bit,
                        (unsigned long *)&monitorpage->trigger_group
                                        [channel->monitor_grp].pending);

        } else {
                VmbusSetEvent(channel->offermsg.child_relid);
        }
}

#if 0
static void VmbusChannelClearEvent(struct vmbus_channel *channel)
{
        struct hv_monitor_page *monitorPage;

        if (Channel->offermsg.monitor_allocated) {
                /* Each u32 represents 32 channels */
                clear_bit(Channel->offermsg.child_relid & 31,
                          (unsigned long *)gVmbusConnection.SendInterruptPage +
                          (Channel->offermsg.child_relid >> 5));

                monitorPage =
                        (struct hv_monitor_page *)gVmbusConnection.MonitorPages;
                monitorPage++; /* Get the child to parent monitor page */

                clear_bit(Channel->monitor_bit,
                          (unsigned long *)&monitorPage->trigger_group
                                        [Channel->monitor_grp].Pending);
        }
}

#endif
/*
 * vmbus_get_debug_info -Retrieve various channel debug info
 */
void vmbus_get_debug_info(struct vmbus_channel *channel,
                              struct vmbus_channel_debug_info *debuginfo)
{
        struct hv_monitor_page *monitorpage;
        u8 monitor_group = (u8)channel->offermsg.monitorid / 32;
        u8 monitor_offset = (u8)channel->offermsg.monitorid % 32;
        /* u32 monitorBit       = 1 << monitorOffset; */

        debuginfo->relid = channel->offermsg.child_relid;
        debuginfo->state = channel->state;
        memcpy(&debuginfo->interfacetype,
               &channel->offermsg.offer.InterfaceType, sizeof(struct hv_guid));
        memcpy(&debuginfo->interface_instance,
               &channel->offermsg.offer.InterfaceInstance,
               sizeof(struct hv_guid));

        monitorpage = (struct hv_monitor_page *)gVmbusConnection.MonitorPages;

        debuginfo->monitorid = channel->offermsg.monitorid;

        debuginfo->servermonitor_pending =
                        monitorpage->trigger_group[monitor_group].pending;
        debuginfo->servermonitor_latency =
                        monitorpage->latency[monitor_group][monitor_offset];
        debuginfo->servermonitor_connectionid =
                        monitorpage->parameter[monitor_group]
                                        [monitor_offset].connectionid.u.id;

        monitorpage++;

        debuginfo->clientmonitor_pending =
                        monitorpage->trigger_group[monitor_group].pending;
        debuginfo->clientmonitor_latency =
                        monitorpage->latency[monitor_group][monitor_offset];
        debuginfo->clientmonitor_connectionid =
                        monitorpage->parameter[monitor_group]
                                        [monitor_offset].connectionid.u.id;

        ringbuffer_get_debuginfo(&channel->inbound, &debuginfo->inbound);
        ringbuffer_get_debuginfo(&channel->outbound, &debuginfo->outbound);
}

/*
 * vmbus_open - Open the specified channel.
 */
int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
                     u32 recv_ringbuffer_size, void *userdata, u32 userdatalen,
                     void (*onchannelcallback)(void *context), void *context)
{
        struct vmbus_channel_open_channel *openMsg;
        struct vmbus_channel_msginfo *openInfo = NULL;
        void *in, *out;
        unsigned long flags;
        int ret, err = 0;

        /* Aligned to page size */
        /* ASSERT(!(SendRingBufferSize & (PAGE_SIZE - 1))); */
        /* ASSERT(!(RecvRingBufferSize & (PAGE_SIZE - 1))); */

        newchannel->onchannel_callback = onchannelcallback;
        newchannel->channel_callback_context = context;

        /* Allocate the ring buffer */
        out = osd_page_alloc((send_ringbuffer_size + recv_ringbuffer_size)
                             >> PAGE_SHIFT);
        if (!out)
                return -ENOMEM;

        /* ASSERT(((unsigned long)out & (PAGE_SIZE-1)) == 0); */

        in = (void *)((unsigned long)out + send_ringbuffer_size);

        newchannel->ringbuffer_pages = out;
        newchannel->ringbuffer_pagecount = (send_ringbuffer_size +
                                           recv_ringbuffer_size) >> PAGE_SHIFT;

        ret = ringbuffer_init(&newchannel->outbound, out, send_ringbuffer_size);
        if (ret != 0) {
                err = ret;
                goto errorout;
        }

        ret = ringbuffer_init(&newchannel->inbound, in, recv_ringbuffer_size);
        if (ret != 0) {
                err = ret;
                goto errorout;
        }


        /* Establish the gpadl for the ring buffer */
        DPRINT_DBG(VMBUS, "Establishing ring buffer's gpadl for channel %p...",
                   newchannel);

        newchannel->ringbuffer_gpadlhandle = 0;

        ret = vmbus_establish_gpadl(newchannel,
                                         newchannel->outbound.ring_buffer,
                                         send_ringbuffer_size +
                                         recv_ringbuffer_size,
                                         &newchannel->ringbuffer_gpadlhandle);

        if (ret != 0) {
                err = ret;
                goto errorout;
        }

        DPRINT_DBG(VMBUS, "channel %p <relid %d gpadl 0x%x send ring %p "
                   "size %d recv ring %p size %d, downstreamoffset %d>",
                   newchannel, newchannel->offermsg.child_relid,
                   newchannel->ringbuffer_gpadlhandle,
                   newchannel->outbound.ring_buffer,
                   newchannel->outbound.ring_size,
                   newchannel->inbound.ring_buffer,
                   newchannel->inbound.ring_size,
                   send_ringbuffer_size);

        /* Create and init the channel open message */
        openInfo = kmalloc(sizeof(*openInfo) +
                           sizeof(struct vmbus_channel_open_channel),
                           GFP_KERNEL);
        if (!openInfo) {
                err = -ENOMEM;
                goto errorout;
        }

        openInfo->waitevent = osd_waitevent_create();
        if (!openInfo->waitevent) {
                err = -ENOMEM;
                goto errorout;
        }

        openMsg = (struct vmbus_channel_open_channel *)openInfo->msg;
        openMsg->header.msgtype = CHANNELMSG_OPENCHANNEL;
        openMsg->openid = newchannel->offermsg.child_relid; /* FIXME */
        openMsg->child_relid = newchannel->offermsg.child_relid;
        openMsg->ringbuffer_gpadlhandle = newchannel->ringbuffer_gpadlhandle;
        openMsg->downstream_ringbuffer_pageoffset = send_ringbuffer_size >>
                                                  PAGE_SHIFT;
        openMsg->server_contextarea_gpadlhandle = 0; /* TODO */

        if (userdatalen > MAX_USER_DEFINED_BYTES) {
                err = -EINVAL;
                goto errorout;
        }

        if (userdatalen)
                memcpy(openMsg->userdata, userdata, userdatalen);

        spin_lock_irqsave(&gVmbusConnection.channelmsg_lock, flags);
        list_add_tail(&openInfo->msglistentry,
                      &gVmbusConnection.ChannelMsgList);
        spin_unlock_irqrestore(&gVmbusConnection.channelmsg_lock, flags);

        DPRINT_DBG(VMBUS, "Sending channel open msg...");

        ret = VmbusPostMessage(openMsg,
                               sizeof(struct vmbus_channel_open_channel));
        if (ret != 0) {
                DPRINT_ERR(VMBUS, "unable to open channel - %d", ret);
                goto Cleanup;
        }

        /* FIXME: Need to time-out here */
        osd_waitevent_wait(openInfo->waitevent);

        if (openInfo->response.open_result.status == 0)
                DPRINT_INFO(VMBUS, "channel <%p> open success!!", newchannel);
        else
                DPRINT_INFO(VMBUS, "channel <%p> open failed - %d!!",
                            newchannel, openInfo->response.open_result.status);

Cleanup:
        spin_lock_irqsave(&gVmbusConnection.channelmsg_lock, flags);
        list_del(&openInfo->msglistentry);
        spin_unlock_irqrestore(&gVmbusConnection.channelmsg_lock, flags);

        kfree(openInfo->waitevent);
        kfree(openInfo);
        return 0;

errorout:
        ringbuffer_cleanup(&newchannel->outbound);
        ringbuffer_cleanup(&newchannel->inbound);
        osd_page_free(out, (send_ringbuffer_size + recv_ringbuffer_size)
                     >> PAGE_SHIFT);
        kfree(openInfo);
        return err;
}
EXPORT_SYMBOL_GPL(vmbus_open);

/*
 * dump_gpadl_body - Dump the gpadl body message to the console for
 * debugging purposes.
 */
static void dump_gpadl_body(struct vmbus_channel_gpadl_body *gpadl, u32 len)
{
        int i;
        int pfncount;

        pfncount = (len - sizeof(struct vmbus_channel_gpadl_body)) /
                   sizeof(u64);
        DPRINT_DBG(VMBUS, "gpadl body - len %d pfn count %d", len, pfncount);

        for (i = 0; i < pfncount; i++)
                DPRINT_DBG(VMBUS, "gpadl body  - %d) pfn %llu",
                           i, gpadl->pfn[i]);
}

/*
 * dump_gpadl_header - Dump the gpadl header message to the console for
 * debugging purposes.
 */
static void dump_gpadl_header(struct vmbus_channel_gpadl_header *gpadl)
{
        int i, j;
        int pagecount;

        DPRINT_DBG(VMBUS,
                   "gpadl header - relid %d, range count %d, range buflen %d",
                   gpadl->child_relid, gpadl->rangecount, gpadl->range_buflen);
        for (i = 0; i < gpadl->rangecount; i++) {
                pagecount = gpadl->range[i].ByteCount >> PAGE_SHIFT;
                pagecount = (pagecount > 26) ? 26 : pagecount;

                DPRINT_DBG(VMBUS, "gpadl range %d - len %d offset %d "
                           "page count %d", i, gpadl->range[i].ByteCount,
                           gpadl->range[i].ByteOffset, pagecount);

                for (j = 0; j < pagecount; j++)
                        DPRINT_DBG(VMBUS, "%d) pfn %llu", j,
                                   gpadl->range[i].PfnArray[j]);
        }
}

/*
 * create_gpadl_header - Creates a gpadl for the specified buffer
 */
static int create_gpadl_header(void *kbuffer, u32 size,
                                         struct vmbus_channel_msginfo **msginfo,
                                         u32 *messagecount)
{
        int i;
        int pagecount;
        unsigned long long pfn;
        struct vmbus_channel_gpadl_header *gpadl_header;
        struct vmbus_channel_gpadl_body *gpadl_body;
        struct vmbus_channel_msginfo *msgheader;
        struct vmbus_channel_msginfo *msgbody = NULL;
        u32 msgsize;

        int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;

        /* ASSERT((kbuffer & (PAGE_SIZE-1)) == 0); */
        /* ASSERT((Size & (PAGE_SIZE-1)) == 0); */

        pagecount = size >> PAGE_SHIFT;
        pfn = virt_to_phys(kbuffer) >> PAGE_SHIFT;

        /* do we need a gpadl body msg */
        pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
                  sizeof(struct vmbus_channel_gpadl_header) -
                  sizeof(struct gpa_range);
        pfncount = pfnsize / sizeof(u64);

        if (pagecount > pfncount) {
                /* we need a gpadl body */
                /* fill in the header */
                msgsize = sizeof(struct vmbus_channel_msginfo) +
                          sizeof(struct vmbus_channel_gpadl_header) +
                          sizeof(struct gpa_range) + pfncount * sizeof(u64);
                msgheader =  kzalloc(msgsize, GFP_KERNEL);
                if (!msgheader)
                        goto nomem;

                INIT_LIST_HEAD(&msgheader->submsglist);
                msgheader->msgsize = msgsize;

                gpadl_header = (struct vmbus_channel_gpadl_header *)
                        msgheader->msg;
                gpadl_header->rangecount = 1;
                gpadl_header->range_buflen = sizeof(struct gpa_range) +
                                         pagecount * sizeof(u64);
                gpadl_header->range[0].ByteOffset = 0;
                gpadl_header->range[0].ByteCount = size;
                for (i = 0; i < pfncount; i++)
                        gpadl_header->range[0].PfnArray[i] = pfn+i;
                *msginfo = msgheader;
                *messagecount = 1;

                pfnsum = pfncount;
                pfnleft = pagecount - pfncount;

                /* how many pfns can we fit */
                pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
                          sizeof(struct vmbus_channel_gpadl_body);
                pfncount = pfnsize / sizeof(u64);

                /* fill in the body */
                while (pfnleft) {
                        if (pfnleft > pfncount)
                                pfncurr = pfncount;
                        else
                                pfncurr = pfnleft;

                        msgsize = sizeof(struct vmbus_channel_msginfo) +
                                  sizeof(struct vmbus_channel_gpadl_body) +
                                  pfncurr * sizeof(u64);
                        msgbody = kzalloc(msgsize, GFP_KERNEL);
                        /* FIXME: we probably need to more if this fails */
                        if (!msgbody)
                                goto nomem;
                        msgbody->msgsize = msgsize;
                        (*messagecount)++;
                        gpadl_body =
                                (struct vmbus_channel_gpadl_body *)msgbody->msg;

                        /*
                         * FIXME:
                         * Gpadl is u32 and we are using a pointer which could
                         * be 64-bit
                         */
                        /* gpadl_body->Gpadl = kbuffer; */
                        for (i = 0; i < pfncurr; i++)
                                gpadl_body->pfn[i] = pfn + pfnsum + i;

                        /* add to msg header */
                        list_add_tail(&msgbody->msglistentry,
                                      &msgheader->submsglist);
                        pfnsum += pfncurr;
                        pfnleft -= pfncurr;
                }
        } else {
                /* everything fits in a header */
                msgsize = sizeof(struct vmbus_channel_msginfo) +
                          sizeof(struct vmbus_channel_gpadl_header) +
                          sizeof(struct gpa_range) + pagecount * sizeof(u64);
                msgheader = kzalloc(msgsize, GFP_KERNEL);
                if (msgheader == NULL)
                        goto nomem;
                msgheader->msgsize = msgsize;

                gpadl_header = (struct vmbus_channel_gpadl_header *)
                        msgheader->msg;
                gpadl_header->rangecount = 1;
                gpadl_header->range_buflen = sizeof(struct gpa_range) +
                                         pagecount * sizeof(u64);
                gpadl_header->range[0].ByteOffset = 0;
                gpadl_header->range[0].ByteCount = size;
                for (i = 0; i < pagecount; i++)
                        gpadl_header->range[0].PfnArray[i] = pfn+i;

                *msginfo = msgheader;
                *messagecount = 1;
        }

        return 0;
nomem:
        kfree(msgheader);
        kfree(msgbody);
        return -ENOMEM;
}

/*
 * vmbus_establish_gpadl - Estabish a GPADL for the specified buffer
 *
 * @channel: a channel
 * @kbuffer: from kmalloc
 * @size: page-size multiple
 * @gpadl_handle: some funky thing
 */
int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
                               u32 size, u32 *gpadl_handle)
{
        struct vmbus_channel_gpadl_header *gpadlmsg;
        struct vmbus_channel_gpadl_body *gpadl_body;
        /* struct vmbus_channel_gpadl_created *gpadlCreated; */
        struct vmbus_channel_msginfo *msginfo = NULL;
        struct vmbus_channel_msginfo *submsginfo;
        u32 msgcount;
        struct list_head *curr;
        u32 next_gpadl_handle;
        unsigned long flags;
        int ret = 0;

        next_gpadl_handle = atomic_read(&gVmbusConnection.NextGpadlHandle);
        atomic_inc(&gVmbusConnection.NextGpadlHandle);

        ret = create_gpadl_header(kbuffer, size, &msginfo, &msgcount);
        if (ret)
                return ret;

        msginfo->waitevent = osd_waitevent_create();
        if (!msginfo->waitevent) {
                ret = -ENOMEM;
                goto Cleanup;
        }

        gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
        gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
        gpadlmsg->child_relid = channel->offermsg.child_relid;
        gpadlmsg->gpadl = next_gpadl_handle;

        dump_gpadl_header(gpadlmsg);

        spin_lock_irqsave(&gVmbusConnection.channelmsg_lock, flags);
        list_add_tail(&msginfo->msglistentry,
                      &gVmbusConnection.ChannelMsgList);

        spin_unlock_irqrestore(&gVmbusConnection.channelmsg_lock, flags);
        DPRINT_DBG(VMBUS, "buffer %p, size %d msg cnt %d",
                   kbuffer, size, msgcount);

        DPRINT_DBG(VMBUS, "Sending GPADL Header - len %zd",
                   msginfo->msgsize - sizeof(*msginfo));

        ret = VmbusPostMessage(gpadlmsg, msginfo->msgsize -
                               sizeof(*msginfo));
        if (ret != 0) {
                DPRINT_ERR(VMBUS, "Unable to open channel - %d", ret);
                goto Cleanup;
        }

        if (msgcount > 1) {
                list_for_each(curr, &msginfo->submsglist) {

                        /* FIXME: should this use list_entry() instead ? */
                        submsginfo = (struct vmbus_channel_msginfo *)curr;
                        gpadl_body =
                             (struct vmbus_channel_gpadl_body *)submsginfo->msg;

                        gpadl_body->header.msgtype =
                                CHANNELMSG_GPADL_BODY;
                        gpadl_body->gpadl = next_gpadl_handle;

                        DPRINT_DBG(VMBUS, "Sending GPADL Body - len %zd",
                                   submsginfo->msgsize -
                                   sizeof(*submsginfo));

                        dump_gpadl_body(gpadl_body, submsginfo->msgsize -
                                      sizeof(*submsginfo));
                        ret = VmbusPostMessage(gpadl_body,
                                               submsginfo->msgsize -
                                               sizeof(*submsginfo));
                        if (ret != 0)
                                goto Cleanup;

                }
        }
        osd_waitevent_wait(msginfo->waitevent);

        /* At this point, we received the gpadl created msg */
        DPRINT_DBG(VMBUS, "Received GPADL created "
                   "(relid %d, status %d handle %x)",
                   channel->offermsg.child_relid,
                   msginfo->response.gpadl_created.creation_status,
                   gpadlmsg->gpadl);

        *gpadl_handle = gpadlmsg->gpadl;

Cleanup:
        spin_lock_irqsave(&gVmbusConnection.channelmsg_lock, flags);
        list_del(&msginfo->msglistentry);
        spin_unlock_irqrestore(&gVmbusConnection.channelmsg_lock, flags);

        kfree(msginfo->waitevent);
        kfree(msginfo);
        return ret;
}
EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);

/*
 * vmbus_teardown_gpadl -Teardown the specified GPADL handle
 */
int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
{
        struct vmbus_channel_gpadl_teardown *msg;
        struct vmbus_channel_msginfo *info;
        unsigned long flags;
        int ret;

        /* ASSERT(gpadl_handle != 0); */

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

        info->waitevent = osd_waitevent_create();
        if (!info->waitevent) {
                kfree(info);
                return -ENOMEM;
        }

        msg = (struct vmbus_channel_gpadl_teardown *)info->msg;

        msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
        msg->child_relid = channel->offermsg.child_relid;
        msg->gpadl = gpadl_handle;

        spin_lock_irqsave(&gVmbusConnection.channelmsg_lock, flags);
        list_add_tail(&info->msglistentry,
                      &gVmbusConnection.ChannelMsgList);
        spin_unlock_irqrestore(&gVmbusConnection.channelmsg_lock, flags);

        ret = VmbusPostMessage(msg,
                               sizeof(struct vmbus_channel_gpadl_teardown));
        if (ret != 0) {
                /* TODO: */
                /* something... */
        }

        osd_waitevent_wait(info->waitevent);

        /* Received a torndown response */
        spin_lock_irqsave(&gVmbusConnection.channelmsg_lock, flags);
        list_del(&info->msglistentry);
        spin_unlock_irqrestore(&gVmbusConnection.channelmsg_lock, flags);

        kfree(info->waitevent);
        kfree(info);
        return ret;
}
EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);

/*
 * vmbus_close - Close the specified channel
 */
void vmbus_close(struct vmbus_channel *channel)
{
        struct vmbus_channel_close_channel *msg;
        struct vmbus_channel_msginfo *info;
        unsigned long flags;
        int ret;

        /* Stop callback and cancel the timer asap */
        channel->onchannel_callback = NULL;
        del_timer_sync(&channel->poll_timer);

        /* Send a closing message */
        info = kmalloc(sizeof(*info) +
                       sizeof(struct vmbus_channel_close_channel), GFP_KERNEL);
        /* FIXME: can't do anything other than return here because the
         *        function is void */
        if (!info)
                return;

        /* info->waitEvent = osd_waitevent_create(); */

        msg = (struct vmbus_channel_close_channel *)info->msg;
        msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
        msg->child_relid = channel->offermsg.child_relid;

        ret = VmbusPostMessage(msg, sizeof(struct vmbus_channel_close_channel));
        if (ret != 0) {
                /* TODO: */
                /* something... */
        }

        /* Tear down the gpadl for the channel's ring buffer */
        if (channel->ringbuffer_gpadlhandle)
                vmbus_teardown_gpadl(channel,
                                          channel->ringbuffer_gpadlhandle);

        /* TODO: Send a msg to release the childRelId */

        /* Cleanup the ring buffers for this channel */
        ringbuffer_cleanup(&channel->outbound);
        ringbuffer_cleanup(&channel->inbound);

        osd_page_free(channel->ringbuffer_pages, channel->ringbuffer_pagecount);

        kfree(info);

        /*
         * If we are closing the channel during an error path in
         * opening the channel, don't free the channel since the
         * caller will free the channel
         */

        if (channel->state == CHANNEL_OPEN_STATE) {
                spin_lock_irqsave(&gVmbusConnection.channel_lock, flags);
                list_del(&channel->listentry);
                spin_unlock_irqrestore(&gVmbusConnection.channel_lock, flags);

                free_channel(channel);
        }
}
EXPORT_SYMBOL_GPL(vmbus_close);

/**
 * vmbus_sendpacket() - Send the specified buffer on the given channel
 * @channel: Pointer to vmbus_channel structure.
 * @buffer: Pointer to the buffer you want to receive the data into.
 * @bufferlen: Maximum size of what the the buffer will hold
 * @requestid: Identifier of the request
 * @type: Type of packet that is being send e.g. negotiate, time
 * packet etc.
 *
 * Sends data in @buffer directly to hyper-v via the vmbus
 * This will send the data unparsed to hyper-v.
 *
 * Mainly used by Hyper-V drivers.
 */
int vmbus_sendpacket(struct vmbus_channel *channel, const void *buffer,
                           u32 bufferlen, u64 requestid,
                           enum vmbus_packet_type type, u32 flags)
{
        struct vmpacket_descriptor desc;
        u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
        u32 packetlen_aligned = ALIGN_UP(packetlen, sizeof(u64));
        struct scatterlist bufferlist[3];
        u64 aligned_data = 0;
        int ret;

        DPRINT_DBG(VMBUS, "channel %p buffer %p len %d",
                   channel, buffer, bufferlen);

        dump_vmbus_channel(channel);

        /* ASSERT((packetLenAligned - packetLen) < sizeof(u64)); */

        /* Setup the descriptor */
        desc.Type = type; /* VmbusPacketTypeDataInBand; */
        desc.Flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
        /* in 8-bytes granularity */
        desc.DataOffset8 = sizeof(struct vmpacket_descriptor) >> 3;
        desc.Length8 = (u16)(packetlen_aligned >> 3);
        desc.TransactionId = requestid;

        sg_init_table(bufferlist, 3);
        sg_set_buf(&bufferlist[0], &desc, sizeof(struct vmpacket_descriptor));
        sg_set_buf(&bufferlist[1], buffer, bufferlen);
        sg_set_buf(&bufferlist[2], &aligned_data,
                   packetlen_aligned - packetlen);

        ret = ringbuffer_write(&channel->outbound, bufferlist, 3);

        /* TODO: We should determine if this is optional */
        if (ret == 0 && !get_ringbuffer_interrupt_mask(&channel->outbound))
                vmbus_setevent(channel);

        return ret;
}
EXPORT_SYMBOL(vmbus_sendpacket);

/*
 * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
 * packets using a GPADL Direct packet type.
 */
int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
                                     struct hv_page_buffer pagebuffers[],
                                     u32 pagecount, void *buffer, u32 bufferlen,
                                     u64 requestid)
{
        int ret;
        int i;
        struct vmbus_channel_packet_page_buffer desc;
        u32 descsize;
        u32 packetlen;
        u32 packetlen_aligned;
        struct scatterlist bufferlist[3];
        u64 aligned_data = 0;

        if (pagecount > MAX_PAGE_BUFFER_COUNT)
                return -EINVAL;

        dump_vmbus_channel(channel);

        /*
         * Adjust the size down since vmbus_channel_packet_page_buffer is the
         * largest size we support
         */
        descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
                          ((MAX_PAGE_BUFFER_COUNT - pagecount) *
                          sizeof(struct hv_page_buffer));
        packetlen = descsize + bufferlen;
        packetlen_aligned = ALIGN_UP(packetlen, sizeof(u64));

        /* ASSERT((packetLenAligned - packetLen) < sizeof(u64)); */

        /* Setup the descriptor */
        desc.type = VmbusPacketTypeDataUsingGpaDirect;
        desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
        desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
        desc.length8 = (u16)(packetlen_aligned >> 3);
        desc.transactionid = requestid;
        desc.rangecount = pagecount;

        for (i = 0; i < pagecount; i++) {
                desc.range[i].Length = pagebuffers[i].Length;
                desc.range[i].Offset = pagebuffers[i].Offset;
                desc.range[i].Pfn        = pagebuffers[i].Pfn;
        }

        sg_init_table(bufferlist, 3);
        sg_set_buf(&bufferlist[0], &desc, descsize);
        sg_set_buf(&bufferlist[1], buffer, bufferlen);
        sg_set_buf(&bufferlist[2], &aligned_data,
                packetlen_aligned - packetlen);

        ret = ringbuffer_write(&channel->outbound, bufferlist, 3);

        /* TODO: We should determine if this is optional */
        if (ret == 0 && !get_ringbuffer_interrupt_mask(&channel->outbound))
                vmbus_setevent(channel);

        return ret;
}
EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);

/*
 * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
 * using a GPADL Direct packet type.
 */
int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
                                struct hv_multipage_buffer *multi_pagebuffer,
                                void *buffer, u32 bufferlen, u64 requestid)
{
        int ret;
        struct vmbus_channel_packet_multipage_buffer desc;
        u32 descsize;
        u32 packetlen;
        u32 packetlen_aligned;
        struct scatterlist bufferlist[3];
        u64 aligned_data = 0;
        u32 pfncount = NUM_PAGES_SPANNED(multi_pagebuffer->Offset,
                                         multi_pagebuffer->Length);

        dump_vmbus_channel(channel);

        DPRINT_DBG(VMBUS, "data buffer - offset %u len %u pfn count %u",
                multi_pagebuffer->Offset,
                multi_pagebuffer->Length, pfncount);

        if ((pfncount < 0) || (pfncount > MAX_MULTIPAGE_BUFFER_COUNT))
                return -EINVAL;

        /*
         * Adjust the size down since vmbus_channel_packet_multipage_buffer is
         * the largest size we support
         */
        descsize = sizeof(struct vmbus_channel_packet_multipage_buffer) -
                          ((MAX_MULTIPAGE_BUFFER_COUNT - pfncount) *
                          sizeof(u64));
        packetlen = descsize + bufferlen;
        packetlen_aligned = ALIGN_UP(packetlen, sizeof(u64));

        /* ASSERT((packetLenAligned - packetLen) < sizeof(u64)); */

        /* Setup the descriptor */
        desc.type = VmbusPacketTypeDataUsingGpaDirect;
        desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
        desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
        desc.length8 = (u16)(packetlen_aligned >> 3);
        desc.transactionid = requestid;
        desc.rangecount = 1;

        desc.range.Length = multi_pagebuffer->Length;
        desc.range.Offset = multi_pagebuffer->Offset;

        memcpy(desc.range.PfnArray, multi_pagebuffer->PfnArray,
               pfncount * sizeof(u64));

        sg_init_table(bufferlist, 3);
        sg_set_buf(&bufferlist[0], &desc, descsize);
        sg_set_buf(&bufferlist[1], buffer, bufferlen);
        sg_set_buf(&bufferlist[2], &aligned_data,
                packetlen_aligned - packetlen);

        ret = ringbuffer_write(&channel->outbound, bufferlist, 3);

        /* TODO: We should determine if this is optional */
        if (ret == 0 && !get_ringbuffer_interrupt_mask(&channel->outbound))
                vmbus_setevent(channel);

        return ret;
}
EXPORT_SYMBOL_GPL(vmbus_sendpacket_multipagebuffer);

/**
 * vmbus_recvpacket() - Retrieve the user packet on the specified channel
 * @channel: Pointer to vmbus_channel structure.
 * @buffer: Pointer to the buffer you want to receive the data into.
 * @bufferlen: Maximum size of what the the buffer will hold
 * @buffer_actual_len: The actual size of the data after it was received
 * @requestid: Identifier of the request
 *
 * Receives directly from the hyper-v vmbus and puts the data it received
 * into Buffer. This will receive the data unparsed from hyper-v.
 *
 * Mainly used by Hyper-V drivers.
 */
int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
                        u32 bufferlen, u32 *buffer_actual_len, u64 *requestid)
{
        struct vmpacket_descriptor desc;
        u32 packetlen;
        u32 userlen;
        int ret;
        unsigned long flags;

        *buffer_actual_len = 0;
        *requestid = 0;

        spin_lock_irqsave(&channel->inbound_lock, flags);

        ret = ringbuffer_peek(&channel->inbound, &desc,
                             sizeof(struct vmpacket_descriptor));
        if (ret != 0) {
                spin_unlock_irqrestore(&channel->inbound_lock, flags);

                /* DPRINT_DBG(VMBUS, "nothing to read!!"); */
                return 0;
        }

        /* VmbusChannelClearEvent(Channel); */

        packetlen = desc.Length8 << 3;
        userlen = packetlen - (desc.DataOffset8 << 3);
        /* ASSERT(userLen > 0); */

        DPRINT_DBG(VMBUS, "packet received on channel %p relid %d <type %d "
                   "flag %d tid %llx pktlen %d datalen %d> ",
                   channel, channel->offermsg.child_relid, desc.Type,
                   desc.Flags, desc.TransactionId, packetlen, userlen);

        *buffer_actual_len = userlen;

        if (userlen > bufferlen) {
                spin_unlock_irqrestore(&channel->inbound_lock, flags);

                DPRINT_ERR(VMBUS, "buffer too small - got %d needs %d",
                           bufferlen, userlen);
                return -1;
        }

        *requestid = desc.TransactionId;

        /* Copy over the packet to the user buffer */
        ret = ringbuffer_read(&channel->inbound, buffer, userlen,
                             (desc.DataOffset8 << 3));

        spin_unlock_irqrestore(&channel->inbound_lock, flags);

        return 0;
}
EXPORT_SYMBOL(vmbus_recvpacket);

/*
 * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
 */
int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
                              u32 bufferlen, u32 *buffer_actual_len,
                              u64 *requestid)
{
        struct vmpacket_descriptor desc;
        u32 packetlen;
        u32 userlen;
        int ret;
        unsigned long flags;

        *buffer_actual_len = 0;
        *requestid = 0;

        spin_lock_irqsave(&channel->inbound_lock, flags);

        ret = ringbuffer_peek(&channel->inbound, &desc,
                             sizeof(struct vmpacket_descriptor));
        if (ret != 0) {
                spin_unlock_irqrestore(&channel->inbound_lock, flags);

                /* DPRINT_DBG(VMBUS, "nothing to read!!"); */
                return 0;
        }

        /* VmbusChannelClearEvent(Channel); */

        packetlen = desc.Length8 << 3;
        userlen = packetlen - (desc.DataOffset8 << 3);

        DPRINT_DBG(VMBUS, "packet received on channel %p relid %d <type %d "
                   "flag %d tid %llx pktlen %d datalen %d> ",
                   channel, channel->offermsg.child_relid, desc.Type,
                   desc.Flags, desc.TransactionId, packetlen, userlen);

        *buffer_actual_len = packetlen;

        if (packetlen > bufferlen) {
                spin_unlock_irqrestore(&channel->inbound_lock, flags);

                DPRINT_ERR(VMBUS, "buffer too small - needed %d bytes but "
                           "got space for only %d bytes", packetlen, bufferlen);
                return -2;
        }

        *requestid = desc.TransactionId;

        /* Copy over the entire packet to the user buffer */
        ret = ringbuffer_read(&channel->inbound, buffer, packetlen, 0);

        spin_unlock_irqrestore(&channel->inbound_lock, flags);
        return 0;
}
EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);

/*
 * vmbus_onchannel_event - Channel event callback
 */
void vmbus_onchannel_event(struct vmbus_channel *channel)
{
        dump_vmbus_channel(channel);
        /* ASSERT(Channel->OnChannelCallback); */

        channel->onchannel_callback(channel->channel_callback_context);

        mod_timer(&channel->poll_timer, jiffies + usecs_to_jiffies(100));
}

/*
 * vmbus_ontimer - Timer event callback
 */
void vmbus_ontimer(unsigned long data)
{
        struct vmbus_channel *channel = (struct vmbus_channel *)data;

        if (channel->onchannel_callback)
                channel->onchannel_callback(channel->channel_callback_context);
}

/*
 * dump_vmbus_channel- Dump vmbus channel info to the console
 */
static void dump_vmbus_channel(struct vmbus_channel *channel)
{
        DPRINT_DBG(VMBUS, "Channel (%d)", channel->offermsg.child_relid);
        dump_ring_info(&channel->outbound, "Outbound ");
        dump_ring_info(&channel->inbound, "Inbound ");
}