drivers/hv/channel_mgmt.c

   1 /*
   2  * Copyright (c) 2009, Microsoft Corporation.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms and conditions of the GNU General Public License,
   6  * version 2, as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  15  * Place - Suite 330, Boston, MA 02111-1307 USA.
  16  *
  17  * Authors:
  18  *   Haiyang Zhang <haiyangz@microsoft.com>
  19  *   Hank Janssen  <hjanssen@microsoft.com>
  20  */
  21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  22
  23 #include <linux/kernel.h>
  24 #include <linux/sched.h>
  25 #include <linux/wait.h>
  26 #include <linux/mm.h>
  27 #include <linux/slab.h>
  28 #include <linux/list.h>
  29 #include <linux/module.h>
  30 #include <linux/completion.h>
  31 #include <linux/hyperv.h>
  32
  33 #include "hyperv_vmbus.h"
  34
  35 struct vmbus_channel_message_table_entry {
  36         enum vmbus_channel_message_type message_type;
  37         void (*message_handler)(struct vmbus_channel_message_header *msg);
  38 };
  39
  40
  41 /**
  42  * vmbus_prep_negotiate_resp() - Create default response for Hyper-V Negotiate message
  43  * @icmsghdrp: Pointer to msg header structure
  44  * @icmsg_negotiate: Pointer to negotiate message structure
  45  * @buf: Raw buffer channel data
  46  *
  47  * @icmsghdrp is of type &struct icmsg_hdr.
  48  * @negop is of type &struct icmsg_negotiate.
  49  * Set up and fill in default negotiate response message.
  50  *
  51  * The max_fw_version specifies the maximum framework version that
  52  * we can support and max _srv_version specifies the maximum service
  53  * version we can support. A special value MAX_SRV_VER can be
  54  * specified to indicate that we can handle the maximum version
  55  * exposed by the host.
  56  *
  57  * Mainly used by Hyper-V drivers.
  58  */
  59 void vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
  60                                 struct icmsg_negotiate *negop, u8 *buf,
  61                                 int max_fw_version, int max_srv_version)
  62 {
  63         int icframe_vercnt;
  64         int icmsg_vercnt;
  65         int i;
  66
  67         icmsghdrp->icmsgsize = 0x10;
  68
  69         negop = (struct icmsg_negotiate *)&buf[
  70                 sizeof(struct vmbuspipe_hdr) +
  71                 sizeof(struct icmsg_hdr)];
  72
  73         icframe_vercnt = negop->icframe_vercnt;
  74         icmsg_vercnt = negop->icmsg_vercnt;
  75
  76         /*
  77          * Select the framework version number we will
  78          * support.
  79          */
  80
  81         for (i = 0; i < negop->icframe_vercnt; i++) {
  82                 if (negop->icversion_data[i].major <= max_fw_version)
  83                         icframe_vercnt = negop->icversion_data[i].major;
  84         }
  85
  86         for (i = negop->icframe_vercnt;
  87                  (i < negop->icframe_vercnt + negop->icmsg_vercnt); i++) {
  88                 if (negop->icversion_data[i].major <= max_srv_version)
  89                         icmsg_vercnt = negop->icversion_data[i].major;
  90         }
  91
  92         /*
  93          * Respond with the maximum framework and service
  94          * version numbers we can support.
  95          */
  96         negop->icframe_vercnt = 1;
  97         negop->icmsg_vercnt = 1;
  98         negop->icversion_data[0].major = icframe_vercnt;
  99         negop->icversion_data[0].minor = 0;
 100         negop->icversion_data[1].major = icmsg_vercnt;
 101         negop->icversion_data[1].minor = 0;
 102 }
 103
 104 EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);
 105
 106 /*
 107  * alloc_channel - Allocate and initialize a vmbus channel object
 108  */
 109 static struct vmbus_channel *alloc_channel(void)
 110 {
 111         struct vmbus_channel *channel;
 112
 113         channel = kzalloc(sizeof(*channel), GFP_ATOMIC);
 114         if (!channel)
 115                 return NULL;
 116
 117         spin_lock_init(&channel->inbound_lock);
 118
 119         channel->controlwq = create_workqueue("hv_vmbus_ctl");
 120         if (!channel->controlwq) {
 121                 kfree(channel);
 122                 return NULL;
 123         }
 124
 125         return channel;
 126 }
 127
 128 /*
 129  * release_hannel - Release the vmbus channel object itself
 130  */
 131 static void release_channel(struct work_struct *work)
 132 {
 133         struct vmbus_channel *channel = container_of(work,
 134                                                      struct vmbus_channel,
 135                                                      work);
 136
 137         destroy_workqueue(channel->controlwq);
 138
 139         kfree(channel);
 140 }
 141
 142 /*
 143  * free_channel - Release the resources used by the vmbus channel object
 144  */
 145 static void free_channel(struct vmbus_channel *channel)
 146 {
 147
 148         /*
 149          * We have to release the channel's workqueue/thread in the vmbus's
 150          * workqueue/thread context
 151          * ie we can't destroy ourselves.
 152          */
 153         INIT_WORK(&channel->work, release_channel);
 154         queue_work(vmbus_connection.work_queue, &channel->work);
 155 }
 156
 157
 158
 159 /*
 160  * vmbus_process_rescind_offer -
 161  * Rescind the offer by initiating a device removal
 162  */
 163 static void vmbus_process_rescind_offer(struct work_struct *work)
 164 {
 165         struct vmbus_channel *channel = container_of(work,
 166                                                      struct vmbus_channel,
 167                                                      work);
 168
 169         vmbus_device_unregister(channel->device_obj);
 170 }
 171
 172 void vmbus_free_channels(void)
 173 {
 174         struct vmbus_channel *channel;
 175
 176         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 177                 vmbus_device_unregister(channel->device_obj);
 178                 kfree(channel->device_obj);
 179                 free_channel(channel);
 180         }
 181 }
 182
 183 /*
 184  * vmbus_process_offer - Process the offer by creating a channel/device
 185  * associated with this offer
 186  */
 187 static void vmbus_process_offer(struct work_struct *work)
 188 {
 189         struct vmbus_channel *newchannel = container_of(work,
 190                                                         struct vmbus_channel,
 191                                                         work);
 192         struct vmbus_channel *channel;
 193         bool fnew = true;
 194         int ret;
 195         unsigned long flags;
 196
 197         /* The next possible work is rescind handling */
 198         INIT_WORK(&newchannel->work, vmbus_process_rescind_offer);
 199
 200         /* Make sure this is a new offer */
 201         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 202
 203         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 204                 if (!uuid_le_cmp(channel->offermsg.offer.if_type,
 205                         newchannel->offermsg.offer.if_type) &&
 206                         !uuid_le_cmp(channel->offermsg.offer.if_instance,
 207                                 newchannel->offermsg.offer.if_instance)) {
 208                         fnew = false;
 209                         break;
 210                 }
 211         }
 212
 213         if (fnew)
 214                 list_add_tail(&newchannel->listentry,
 215                               &vmbus_connection.chn_list);
 216
 217         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 218
 219         if (!fnew) {
 220                 free_channel(newchannel);
 221                 return;
 222         }
 223
 224         /*
 225          * Start the process of binding this offer to the driver
 226          * We need to set the DeviceObject field before calling
 227          * vmbus_child_dev_add()
 228          */
 229         newchannel->device_obj = vmbus_device_create(
 230                 &newchannel->offermsg.offer.if_type,
 231                 &newchannel->offermsg.offer.if_instance,
 232                 newchannel);
 233
 234         /*
 235          * Add the new device to the bus. This will kick off device-driver
 236          * binding which eventually invokes the device driver's AddDevice()
 237          * method.
 238          */
 239         ret = vmbus_device_register(newchannel->device_obj);
 240         if (ret != 0) {
 241                 pr_err("unable to add child device object (relid %d)\n",
 242                            newchannel->offermsg.child_relid);
 243
 244                 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 245                 list_del(&newchannel->listentry);
 246                 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 247                 kfree(newchannel->device_obj);
 248
 249                 free_channel(newchannel);
 250         } else {
 251                 /*
 252                  * This state is used to indicate a successful open
 253                  * so that when we do close the channel normally, we
 254                  * can cleanup properly
 255                  */
 256                 newchannel->state = CHANNEL_OPEN_STATE;
 257         }
 258 }
 259
 260 enum {
 261         IDE = 0,
 262         SCSI,
 263         NIC,
 264         MAX_PERF_CHN,
 265 };
 266
 267 /*
 268  * This is an array of device_ids (device types) that are performance critical.
 269  * We attempt to distribute the interrupt load for these devices across
 270  * all available CPUs.
 271  */
 272 static const struct hv_vmbus_device_id hp_devs[] = {
 273         /* IDE */
 274         { HV_IDE_GUID, },
 275         /* Storage - SCSI */
 276         { HV_SCSI_GUID, },
 277         /* Network */
 278         { HV_NIC_GUID, },
 279 };
 280
 281
 282 /*
 283  * We use this state to statically distribute the channel interrupt load.
 284  */
 285 static u32  next_vp;
 286
 287 /*
 288  * Starting with Win8, we can statically distribute the incoming
 289  * channel interrupt load by binding a channel to VCPU. We
 290  * implement here a simple round robin scheme for distributing
 291  * the interrupt load.
 292  * We will bind channels that are not performance critical to cpu 0 and
 293  * performance critical channels (IDE, SCSI and Network) will be uniformly
 294  * distributed across all available CPUs.
 295  */
 296 static u32 get_vp_index(uuid_le *type_guid)
 297 {
 298         u32 cur_cpu;
 299         int i;
 300         bool perf_chn = false;
 301         u32 max_cpus = num_online_cpus();
 302
 303         for (i = IDE; i < MAX_PERF_CHN; i++) {
 304                 if (!memcmp(type_guid->b, hp_devs[i].guid,
 305                                  sizeof(uuid_le))) {
 306                         perf_chn = true;
 307                         break;
 308                 }
 309         }
 310         if ((vmbus_proto_version == VERSION_WS2008) ||
 311             (vmbus_proto_version == VERSION_WIN7) || (!perf_chn)) {
 312                 /*
 313                  * Prior to win8, all channel interrupts are
 314                  * delivered on cpu 0.
 315                  * Also if the channel is not a performance critical
 316                  * channel, bind it to cpu 0.
 317                  */
 318                 return 0;
 319         }
 320         cur_cpu = (++next_vp % max_cpus);
 321         return cur_cpu;
 322 }
 323
 324 /*
 325  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 326  *
 327  */
 328 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 329 {
 330         struct vmbus_channel_offer_channel *offer;
 331         struct vmbus_channel *newchannel;
 332
 333         offer = (struct vmbus_channel_offer_channel *)hdr;
 334
 335         /* Allocate the channel object and save this offer. */
 336         newchannel = alloc_channel();
 337         if (!newchannel) {
 338                 pr_err("Unable to allocate channel object\n");
 339                 return;
 340         }
 341
 342         /*
 343          * By default we setup state to enable batched
 344          * reading. A specific service can choose to
 345          * disable this prior to opening the channel.
 346          */
 347         newchannel->batched_reading = true;
 348
 349         /*
 350          * Setup state for signalling the host.
 351          */
 352         newchannel->sig_event = (struct hv_input_signal_event *)
 353                                 (ALIGN((unsigned long)
 354                                 &newchannel->sig_buf,
 355                                 HV_HYPERCALL_PARAM_ALIGN));
 356
 357         newchannel->sig_event->connectionid.asu32 = 0;
 358         newchannel->sig_event->connectionid.u.id = VMBUS_EVENT_CONNECTION_ID;
 359         newchannel->sig_event->flag_number = 0;
 360         newchannel->sig_event->rsvdz = 0;
 361
 362         if (vmbus_proto_version != VERSION_WS2008) {
 363                 newchannel->is_dedicated_interrupt =
 364                                 (offer->is_dedicated_interrupt != 0);
 365                 newchannel->sig_event->connectionid.u.id =
 366                                 offer->connection_id;
 367         }
 368
 369         newchannel->target_vp = get_vp_index(&offer->offer.if_type);
 370
 371         memcpy(&newchannel->offermsg, offer,
 372                sizeof(struct vmbus_channel_offer_channel));
 373         newchannel->monitor_grp = (u8)offer->monitorid / 32;
 374         newchannel->monitor_bit = (u8)offer->monitorid % 32;
 375
 376         INIT_WORK(&newchannel->work, vmbus_process_offer);
 377         queue_work(newchannel->controlwq, &newchannel->work);
 378 }
 379
 380 /*
 381  * vmbus_onoffer_rescind - Rescind offer handler.
 382  *
 383  * We queue a work item to process this offer synchronously
 384  */
 385 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 386 {
 387         struct vmbus_channel_rescind_offer *rescind;
 388         struct vmbus_channel *channel;
 389
 390         rescind = (struct vmbus_channel_rescind_offer *)hdr;
 391         channel = relid2channel(rescind->child_relid);
 392
 393         if (channel == NULL)
 394                 /* Just return here, no channel found */
 395                 return;
 396
 397         /* work is initialized for vmbus_process_rescind_offer() from
 398          * vmbus_process_offer() where the channel got created */
 399         queue_work(channel->controlwq, &channel->work);
 400 }
 401
 402 /*
 403  * vmbus_onoffers_delivered -
 404  * This is invoked when all offers have been delivered.
 405  *
 406  * Nothing to do here.
 407  */
 408 static void vmbus_onoffers_delivered(
 409                         struct vmbus_channel_message_header *hdr)
 410 {
 411 }
 412
 413 /*
 414  * vmbus_onopen_result - Open result handler.
 415  *
 416  * This is invoked when we received a response to our channel open request.
 417  * Find the matching request, copy the response and signal the requesting
 418  * thread.
 419  */
 420 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
 421 {
 422         struct vmbus_channel_open_result *result;
 423         struct vmbus_channel_msginfo *msginfo;
 424         struct vmbus_channel_message_header *requestheader;
 425         struct vmbus_channel_open_channel *openmsg;
 426         unsigned long flags;
 427
 428         result = (struct vmbus_channel_open_result *)hdr;
 429
 430         /*
 431          * Find the open msg, copy the result and signal/unblock the wait event
 432          */
 433         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 434
 435         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 436                                 msglistentry) {
 437                 requestheader =
 438                         (struct vmbus_channel_message_header *)msginfo->msg;
 439
 440                 if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
 441                         openmsg =
 442                         (struct vmbus_channel_open_channel *)msginfo->msg;
 443                         if (openmsg->child_relid == result->child_relid &&
 444                             openmsg->openid == result->openid) {
 445                                 memcpy(&msginfo->response.open_result,
 446                                        result,
 447                                        sizeof(
 448                                         struct vmbus_channel_open_result));
 449                                 complete(&msginfo->waitevent);
 450                                 break;
 451                         }
 452                 }
 453         }
 454         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 455 }
 456
 457 /*
 458  * vmbus_ongpadl_created - GPADL created handler.
 459  *
 460  * This is invoked when we received a response to our gpadl create request.
 461  * Find the matching request, copy the response and signal the requesting
 462  * thread.
 463  */
 464 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
 465 {
 466         struct vmbus_channel_gpadl_created *gpadlcreated;
 467         struct vmbus_channel_msginfo *msginfo;
 468         struct vmbus_channel_message_header *requestheader;
 469         struct vmbus_channel_gpadl_header *gpadlheader;
 470         unsigned long flags;
 471
 472         gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
 473
 474         /*
 475          * Find the establish msg, copy the result and signal/unblock the wait
 476          * event
 477          */
 478         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 479
 480         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 481                                 msglistentry) {
 482                 requestheader =
 483                         (struct vmbus_channel_message_header *)msginfo->msg;
 484
 485                 if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
 486                         gpadlheader =
 487                         (struct vmbus_channel_gpadl_header *)requestheader;
 488
 489                         if ((gpadlcreated->child_relid ==
 490                              gpadlheader->child_relid) &&
 491                             (gpadlcreated->gpadl == gpadlheader->gpadl)) {
 492                                 memcpy(&msginfo->response.gpadl_created,
 493                                        gpadlcreated,
 494                                        sizeof(
 495                                         struct vmbus_channel_gpadl_created));
 496                                 complete(&msginfo->waitevent);
 497                                 break;
 498                         }
 499                 }
 500         }
 501         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 502 }
 503
 504 /*
 505  * vmbus_ongpadl_torndown - GPADL torndown handler.
 506  *
 507  * This is invoked when we received a response to our gpadl teardown request.
 508  * Find the matching request, copy the response and signal the requesting
 509  * thread.
 510  */
 511 static void vmbus_ongpadl_torndown(
 512                         struct vmbus_channel_message_header *hdr)
 513 {
 514         struct vmbus_channel_gpadl_torndown *gpadl_torndown;
 515         struct vmbus_channel_msginfo *msginfo;
 516         struct vmbus_channel_message_header *requestheader;
 517         struct vmbus_channel_gpadl_teardown *gpadl_teardown;
 518         unsigned long flags;
 519
 520         gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
 521
 522         /*
 523          * Find the open msg, copy the result and signal/unblock the wait event
 524          */
 525         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 526
 527         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 528                                 msglistentry) {
 529                 requestheader =
 530                         (struct vmbus_channel_message_header *)msginfo->msg;
 531
 532                 if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
 533                         gpadl_teardown =
 534                         (struct vmbus_channel_gpadl_teardown *)requestheader;
 535
 536                         if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
 537                                 memcpy(&msginfo->response.gpadl_torndown,
 538                                        gpadl_torndown,
 539                                        sizeof(
 540                                         struct vmbus_channel_gpadl_torndown));
 541                                 complete(&msginfo->waitevent);
 542                                 break;
 543                         }
 544                 }
 545         }
 546         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 547 }
 548
 549 /*
 550  * vmbus_onversion_response - Version response handler
 551  *
 552  * This is invoked when we received a response to our initiate contact request.
 553  * Find the matching request, copy the response and signal the requesting
 554  * thread.
 555  */
 556 static void vmbus_onversion_response(
 557                 struct vmbus_channel_message_header *hdr)
 558 {
 559         struct vmbus_channel_msginfo *msginfo;
 560         struct vmbus_channel_message_header *requestheader;
 561         struct vmbus_channel_version_response *version_response;
 562         unsigned long flags;
 563
 564         version_response = (struct vmbus_channel_version_response *)hdr;
 565         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 566
 567         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 568                                 msglistentry) {
 569                 requestheader =
 570                         (struct vmbus_channel_message_header *)msginfo->msg;
 571
 572                 if (requestheader->msgtype ==
 573                     CHANNELMSG_INITIATE_CONTACT) {
 574                         memcpy(&msginfo->response.version_response,
 575                               version_response,
 576                               sizeof(struct vmbus_channel_version_response));
 577                         complete(&msginfo->waitevent);
 578                 }
 579         }
 580         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 581 }
 582
 583 /* Channel message dispatch table */
 584 static struct vmbus_channel_message_table_entry
 585         channel_message_table[CHANNELMSG_COUNT] = {
 586         {CHANNELMSG_INVALID,                    NULL},
 587         {CHANNELMSG_OFFERCHANNEL,               vmbus_onoffer},
 588         {CHANNELMSG_RESCIND_CHANNELOFFER,       vmbus_onoffer_rescind},
 589         {CHANNELMSG_REQUESTOFFERS,              NULL},
 590         {CHANNELMSG_ALLOFFERS_DELIVERED,        vmbus_onoffers_delivered},
 591         {CHANNELMSG_OPENCHANNEL,                NULL},
 592         {CHANNELMSG_OPENCHANNEL_RESULT, vmbus_onopen_result},
 593         {CHANNELMSG_CLOSECHANNEL,               NULL},
 594         {CHANNELMSG_GPADL_HEADER,               NULL},
 595         {CHANNELMSG_GPADL_BODY,         NULL},
 596         {CHANNELMSG_GPADL_CREATED,              vmbus_ongpadl_created},
 597         {CHANNELMSG_GPADL_TEARDOWN,             NULL},
 598         {CHANNELMSG_GPADL_TORNDOWN,             vmbus_ongpadl_torndown},
 599         {CHANNELMSG_RELID_RELEASED,             NULL},
 600         {CHANNELMSG_INITIATE_CONTACT,           NULL},
 601         {CHANNELMSG_VERSION_RESPONSE,           vmbus_onversion_response},
 602         {CHANNELMSG_UNLOAD,                     NULL},
 603 };
 604
 605 /*
 606  * vmbus_onmessage - Handler for channel protocol messages.
 607  *
 608  * This is invoked in the vmbus worker thread context.
 609  */
 610 void vmbus_onmessage(void *context)
 611 {
 612         struct hv_message *msg = context;
 613         struct vmbus_channel_message_header *hdr;
 614         int size;
 615
 616         hdr = (struct vmbus_channel_message_header *)msg->u.payload;
 617         size = msg->header.payload_size;
 618
 619         if (hdr->msgtype >= CHANNELMSG_COUNT) {
 620                 pr_err("Received invalid channel message type %d size %d\n",
 621                            hdr->msgtype, size);
 622                 print_hex_dump_bytes("", DUMP_PREFIX_NONE,
 623                                      (unsigned char *)msg->u.payload, size);
 624                 return;
 625         }
 626
 627         if (channel_message_table[hdr->msgtype].message_handler)
 628                 channel_message_table[hdr->msgtype].message_handler(hdr);
 629         else
 630                 pr_err("Unhandled channel message type %d\n", hdr->msgtype);
 631 }
 632
 633 /*
 634  * vmbus_request_offers - Send a request to get all our pending offers.
 635  */
 636 int vmbus_request_offers(void)
 637 {
 638         struct vmbus_channel_message_header *msg;
 639         struct vmbus_channel_msginfo *msginfo;
 640         int ret, t;
 641
 642         msginfo = kmalloc(sizeof(*msginfo) +
 643                           sizeof(struct vmbus_channel_message_header),
 644                           GFP_KERNEL);
 645         if (!msginfo)
 646                 return -ENOMEM;
 647
 648         init_completion(&msginfo->waitevent);
 649
 650         msg = (struct vmbus_channel_message_header *)msginfo->msg;
 651
 652         msg->msgtype = CHANNELMSG_REQUESTOFFERS;
 653
 654
 655         ret = vmbus_post_msg(msg,
 656                                sizeof(struct vmbus_channel_message_header));
 657         if (ret != 0) {
 658                 pr_err("Unable to request offers - %d\n", ret);
 659
 660                 goto cleanup;
 661         }
 662
 663         t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
 664         if (t == 0) {
 665                 ret = -ETIMEDOUT;
 666                 goto cleanup;
 667         }
 668
 669
 670
 671 cleanup:
 672         kfree(msginfo);
 673
 674         return ret;
 675 }
 676
 677 /* eof */