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 #define MAX_MSG_TYPES                    4
  41 #define MAX_NUM_DEVICE_CLASSES_SUPPORTED 8
  42
  43 static const uuid_le
  44         supported_device_classes[MAX_NUM_DEVICE_CLASSES_SUPPORTED] = {
  45         /* {ba6163d9-04a1-4d29-b605-72e2ffb1dc7f} */
  46         /* Storage - SCSI */
  47         {
  48                 .b  = {
  49                         0xd9, 0x63, 0x61, 0xba, 0xa1, 0x04, 0x29, 0x4d,
  50                         0xb6, 0x05, 0x72, 0xe2, 0xff, 0xb1, 0xdc, 0x7f
  51                 }
  52         },
  53
  54         /* {F8615163-DF3E-46c5-913F-F2D2F965ED0E} */
  55         /* Network */
  56         {
  57                 .b = {
  58                         0x63, 0x51, 0x61, 0xF8, 0x3E, 0xDF, 0xc5, 0x46,
  59                         0x91, 0x3F, 0xF2, 0xD2, 0xF9, 0x65, 0xED, 0x0E
  60                 }
  61         },
  62
  63         /* {CFA8B69E-5B4A-4cc0-B98B-8BA1A1F3F95A} */
  64         /* Input */
  65         {
  66                 .b = {
  67                         0x9E, 0xB6, 0xA8, 0xCF, 0x4A, 0x5B, 0xc0, 0x4c,
  68                         0xB9, 0x8B, 0x8B, 0xA1, 0xA1, 0xF3, 0xF9, 0x5A
  69                 }
  70         },
  71
  72         /* {32412632-86cb-44a2-9b5c-50d1417354f5} */
  73         /* IDE */
  74         {
  75                 .b = {
  76                         0x32, 0x26, 0x41, 0x32, 0xcb, 0x86, 0xa2, 0x44,
  77                         0x9b, 0x5c, 0x50, 0xd1, 0x41, 0x73, 0x54, 0xf5
  78                 }
  79         },
  80         /* 0E0B6031-5213-4934-818B-38D90CED39DB */
  81         /* Shutdown */
  82         {
  83                 .b = {
  84                         0x31, 0x60, 0x0B, 0X0E, 0x13, 0x52, 0x34, 0x49,
  85                         0x81, 0x8B, 0x38, 0XD9, 0x0C, 0xED, 0x39, 0xDB
  86                 }
  87         },
  88         /* {9527E630-D0AE-497b-ADCE-E80AB0175CAF} */
  89         /* TimeSync */
  90         {
  91                 .b = {
  92                         0x30, 0xe6, 0x27, 0x95, 0xae, 0xd0, 0x7b, 0x49,
  93                         0xad, 0xce, 0xe8, 0x0a, 0xb0, 0x17, 0x5c, 0xaf
  94                 }
  95         },
  96         /* {57164f39-9115-4e78-ab55-382f3bd5422d} */
  97         /* Heartbeat */
  98         {
  99                 .b = {
 100                         0x39, 0x4f, 0x16, 0x57, 0x15, 0x91, 0x78, 0x4e,
 101                         0xab, 0x55, 0x38, 0x2f, 0x3b, 0xd5, 0x42, 0x2d
 102                 }
 103         },
 104         /* {A9A0F4E7-5A45-4d96-B827-8A841E8C03E6} */
 105         /* KVP */
 106         {
 107                 .b = {
 108                         0xe7, 0xf4, 0xa0, 0xa9, 0x45, 0x5a, 0x96, 0x4d,
 109                         0xb8, 0x27, 0x8a, 0x84, 0x1e, 0x8c, 0x3,  0xe6
 110         }
 111         },
 112
 113 };
 114
 115
 116 /**
 117  * vmbus_prep_negotiate_resp() - Create default response for Hyper-V Negotiate message
 118  * @icmsghdrp: Pointer to msg header structure
 119  * @icmsg_negotiate: Pointer to negotiate message structure
 120  * @buf: Raw buffer channel data
 121  *
 122  * @icmsghdrp is of type &struct icmsg_hdr.
 123  * @negop is of type &struct icmsg_negotiate.
 124  * Set up and fill in default negotiate response message. This response can
 125  * come from both the vmbus driver and the hv_utils driver. The current api
 126  * will respond properly to both Windows 2008 and Windows 2008-R2 operating
 127  * systems.
 128  *
 129  * Mainly used by Hyper-V drivers.
 130  */
 131 void vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
 132                                struct icmsg_negotiate *negop, u8 *buf)
 133 {
 134         if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
 135                 icmsghdrp->icmsgsize = 0x10;
 136
 137                 negop = (struct icmsg_negotiate *)&buf[
 138                         sizeof(struct vmbuspipe_hdr) +
 139                         sizeof(struct icmsg_hdr)];
 140
 141                 if (negop->icframe_vercnt == 2 &&
 142                    negop->icversion_data[1].major == 3) {
 143                         negop->icversion_data[0].major = 3;
 144                         negop->icversion_data[0].minor = 0;
 145                         negop->icversion_data[1].major = 3;
 146                         negop->icversion_data[1].minor = 0;
 147                 } else {
 148                         negop->icversion_data[0].major = 1;
 149                         negop->icversion_data[0].minor = 0;
 150                         negop->icversion_data[1].major = 1;
 151                         negop->icversion_data[1].minor = 0;
 152                 }
 153
 154                 negop->icframe_vercnt = 1;
 155                 negop->icmsg_vercnt = 1;
 156         }
 157 }
 158 EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);
 159
 160 /*
 161  * alloc_channel - Allocate and initialize a vmbus channel object
 162  */
 163 static struct vmbus_channel *alloc_channel(void)
 164 {
 165         struct vmbus_channel *channel;
 166
 167         channel = kzalloc(sizeof(*channel), GFP_ATOMIC);
 168         if (!channel)
 169                 return NULL;
 170
 171         spin_lock_init(&channel->inbound_lock);
 172
 173         channel->controlwq = create_workqueue("hv_vmbus_ctl");
 174         if (!channel->controlwq) {
 175                 kfree(channel);
 176                 return NULL;
 177         }
 178
 179         return channel;
 180 }
 181
 182 /*
 183  * release_hannel - Release the vmbus channel object itself
 184  */
 185 static void release_channel(struct work_struct *work)
 186 {
 187         struct vmbus_channel *channel = container_of(work,
 188                                                      struct vmbus_channel,
 189                                                      work);
 190
 191         destroy_workqueue(channel->controlwq);
 192
 193         kfree(channel);
 194 }
 195
 196 /*
 197  * free_channel - Release the resources used by the vmbus channel object
 198  */
 199 void free_channel(struct vmbus_channel *channel)
 200 {
 201
 202         /*
 203          * We have to release the channel's workqueue/thread in the vmbus's
 204          * workqueue/thread context
 205          * ie we can't destroy ourselves.
 206          */
 207         INIT_WORK(&channel->work, release_channel);
 208         queue_work(vmbus_connection.work_queue, &channel->work);
 209 }
 210
 211
 212
 213 /*
 214  * vmbus_process_rescind_offer -
 215  * Rescind the offer by initiating a device removal
 216  */
 217 static void vmbus_process_rescind_offer(struct work_struct *work)
 218 {
 219         struct vmbus_channel *channel = container_of(work,
 220                                                      struct vmbus_channel,
 221                                                      work);
 222
 223         vmbus_device_unregister(channel->device_obj);
 224 }
 225
 226 /*
 227  * vmbus_process_offer - Process the offer by creating a channel/device
 228  * associated with this offer
 229  */
 230 static void vmbus_process_offer(struct work_struct *work)
 231 {
 232         struct vmbus_channel *newchannel = container_of(work,
 233                                                         struct vmbus_channel,
 234                                                         work);
 235         struct vmbus_channel *channel;
 236         bool fnew = true;
 237         int ret;
 238         unsigned long flags;
 239
 240         /* The next possible work is rescind handling */
 241         INIT_WORK(&newchannel->work, vmbus_process_rescind_offer);
 242
 243         /* Make sure this is a new offer */
 244         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 245
 246         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 247                 if (!uuid_le_cmp(channel->offermsg.offer.if_type,
 248                         newchannel->offermsg.offer.if_type) &&
 249                         !uuid_le_cmp(channel->offermsg.offer.if_instance,
 250                                 newchannel->offermsg.offer.if_instance)) {
 251                         fnew = false;
 252                         break;
 253                 }
 254         }
 255
 256         if (fnew)
 257                 list_add_tail(&newchannel->listentry,
 258                               &vmbus_connection.chn_list);
 259
 260         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 261
 262         if (!fnew) {
 263                 free_channel(newchannel);
 264                 return;
 265         }
 266
 267         /*
 268          * Start the process of binding this offer to the driver
 269          * We need to set the DeviceObject field before calling
 270          * vmbus_child_dev_add()
 271          */
 272         newchannel->device_obj = vmbus_device_create(
 273                 &newchannel->offermsg.offer.if_type,
 274                 &newchannel->offermsg.offer.if_instance,
 275                 newchannel);
 276
 277         /*
 278          * Add the new device to the bus. This will kick off device-driver
 279          * binding which eventually invokes the device driver's AddDevice()
 280          * method.
 281          */
 282         ret = vmbus_device_register(newchannel->device_obj);
 283         if (ret != 0) {
 284                 pr_err("unable to add child device object (relid %d)\n",
 285                            newchannel->offermsg.child_relid);
 286
 287                 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 288                 list_del(&newchannel->listentry);
 289                 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 290
 291                 free_channel(newchannel);
 292         } else {
 293                 /*
 294                  * This state is used to indicate a successful open
 295                  * so that when we do close the channel normally, we
 296                  * can cleanup properly
 297                  */
 298                 newchannel->state = CHANNEL_OPEN_STATE;
 299         }
 300 }
 301
 302 /*
 303  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 304  *
 305  */
 306 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 307 {
 308         struct vmbus_channel_offer_channel *offer;
 309         struct vmbus_channel *newchannel;
 310         uuid_le *guidtype;
 311         uuid_le *guidinstance;
 312         int i;
 313         int fsupported = 0;
 314
 315         offer = (struct vmbus_channel_offer_channel *)hdr;
 316         for (i = 0; i < MAX_NUM_DEVICE_CLASSES_SUPPORTED; i++) {
 317                 if (!uuid_le_cmp(offer->offer.if_type,
 318                                 supported_device_classes[i])) {
 319                         fsupported = 1;
 320                         break;
 321                 }
 322         }
 323
 324         if (!fsupported)
 325                 return;
 326
 327         guidtype = &offer->offer.if_type;
 328         guidinstance = &offer->offer.if_instance;
 329
 330         /* Allocate the channel object and save this offer. */
 331         newchannel = alloc_channel();
 332         if (!newchannel) {
 333                 pr_err("Unable to allocate channel object\n");
 334                 return;
 335         }
 336
 337         memcpy(&newchannel->offermsg, offer,
 338                sizeof(struct vmbus_channel_offer_channel));
 339         newchannel->monitor_grp = (u8)offer->monitorid / 32;
 340         newchannel->monitor_bit = (u8)offer->monitorid % 32;
 341
 342         INIT_WORK(&newchannel->work, vmbus_process_offer);
 343         queue_work(newchannel->controlwq, &newchannel->work);
 344 }
 345
 346 /*
 347  * vmbus_onoffer_rescind - Rescind offer handler.
 348  *
 349  * We queue a work item to process this offer synchronously
 350  */
 351 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 352 {
 353         struct vmbus_channel_rescind_offer *rescind;
 354         struct vmbus_channel *channel;
 355
 356         rescind = (struct vmbus_channel_rescind_offer *)hdr;
 357         channel = relid2channel(rescind->child_relid);
 358
 359         if (channel == NULL)
 360                 /* Just return here, no channel found */
 361                 return;
 362
 363         /* work is initialized for vmbus_process_rescind_offer() from
 364          * vmbus_process_offer() where the channel got created */
 365         queue_work(channel->controlwq, &channel->work);
 366 }
 367
 368 /*
 369  * vmbus_onoffers_delivered -
 370  * This is invoked when all offers have been delivered.
 371  *
 372  * Nothing to do here.
 373  */
 374 static void vmbus_onoffers_delivered(
 375                         struct vmbus_channel_message_header *hdr)
 376 {
 377 }
 378
 379 /*
 380  * vmbus_onopen_result - Open result handler.
 381  *
 382  * This is invoked when we received a response to our channel open request.
 383  * Find the matching request, copy the response and signal the requesting
 384  * thread.
 385  */
 386 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
 387 {
 388         struct vmbus_channel_open_result *result;
 389         struct vmbus_channel_msginfo *msginfo;
 390         struct vmbus_channel_message_header *requestheader;
 391         struct vmbus_channel_open_channel *openmsg;
 392         unsigned long flags;
 393
 394         result = (struct vmbus_channel_open_result *)hdr;
 395
 396         /*
 397          * Find the open msg, copy the result and signal/unblock the wait event
 398          */
 399         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 400
 401         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 402                                 msglistentry) {
 403                 requestheader =
 404                         (struct vmbus_channel_message_header *)msginfo->msg;
 405
 406                 if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
 407                         openmsg =
 408                         (struct vmbus_channel_open_channel *)msginfo->msg;
 409                         if (openmsg->child_relid == result->child_relid &&
 410                             openmsg->openid == result->openid) {
 411                                 memcpy(&msginfo->response.open_result,
 412                                        result,
 413                                        sizeof(
 414                                         struct vmbus_channel_open_result));
 415                                 complete(&msginfo->waitevent);
 416                                 break;
 417                         }
 418                 }
 419         }
 420         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 421 }
 422
 423 /*
 424  * vmbus_ongpadl_created - GPADL created handler.
 425  *
 426  * This is invoked when we received a response to our gpadl create request.
 427  * Find the matching request, copy the response and signal the requesting
 428  * thread.
 429  */
 430 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
 431 {
 432         struct vmbus_channel_gpadl_created *gpadlcreated;
 433         struct vmbus_channel_msginfo *msginfo;
 434         struct vmbus_channel_message_header *requestheader;
 435         struct vmbus_channel_gpadl_header *gpadlheader;
 436         unsigned long flags;
 437
 438         gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
 439
 440         /*
 441          * Find the establish msg, copy the result and signal/unblock the wait
 442          * event
 443          */
 444         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 445
 446         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 447                                 msglistentry) {
 448                 requestheader =
 449                         (struct vmbus_channel_message_header *)msginfo->msg;
 450
 451                 if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
 452                         gpadlheader =
 453                         (struct vmbus_channel_gpadl_header *)requestheader;
 454
 455                         if ((gpadlcreated->child_relid ==
 456                              gpadlheader->child_relid) &&
 457                             (gpadlcreated->gpadl == gpadlheader->gpadl)) {
 458                                 memcpy(&msginfo->response.gpadl_created,
 459                                        gpadlcreated,
 460                                        sizeof(
 461                                         struct vmbus_channel_gpadl_created));
 462                                 complete(&msginfo->waitevent);
 463                                 break;
 464                         }
 465                 }
 466         }
 467         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 468 }
 469
 470 /*
 471  * vmbus_ongpadl_torndown - GPADL torndown handler.
 472  *
 473  * This is invoked when we received a response to our gpadl teardown request.
 474  * Find the matching request, copy the response and signal the requesting
 475  * thread.
 476  */
 477 static void vmbus_ongpadl_torndown(
 478                         struct vmbus_channel_message_header *hdr)
 479 {
 480         struct vmbus_channel_gpadl_torndown *gpadl_torndown;
 481         struct vmbus_channel_msginfo *msginfo;
 482         struct vmbus_channel_message_header *requestheader;
 483         struct vmbus_channel_gpadl_teardown *gpadl_teardown;
 484         unsigned long flags;
 485
 486         gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
 487
 488         /*
 489          * Find the open msg, copy the result and signal/unblock the wait event
 490          */
 491         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 492
 493         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 494                                 msglistentry) {
 495                 requestheader =
 496                         (struct vmbus_channel_message_header *)msginfo->msg;
 497
 498                 if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
 499                         gpadl_teardown =
 500                         (struct vmbus_channel_gpadl_teardown *)requestheader;
 501
 502                         if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
 503                                 memcpy(&msginfo->response.gpadl_torndown,
 504                                        gpadl_torndown,
 505                                        sizeof(
 506                                         struct vmbus_channel_gpadl_torndown));
 507                                 complete(&msginfo->waitevent);
 508                                 break;
 509                         }
 510                 }
 511         }
 512         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 513 }
 514
 515 /*
 516  * vmbus_onversion_response - Version response handler
 517  *
 518  * This is invoked when we received a response to our initiate contact request.
 519  * Find the matching request, copy the response and signal the requesting
 520  * thread.
 521  */
 522 static void vmbus_onversion_response(
 523                 struct vmbus_channel_message_header *hdr)
 524 {
 525         struct vmbus_channel_msginfo *msginfo;
 526         struct vmbus_channel_message_header *requestheader;
 527         struct vmbus_channel_initiate_contact *initiate;
 528         struct vmbus_channel_version_response *version_response;
 529         unsigned long flags;
 530
 531         version_response = (struct vmbus_channel_version_response *)hdr;
 532         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 533
 534         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 535                                 msglistentry) {
 536                 requestheader =
 537                         (struct vmbus_channel_message_header *)msginfo->msg;
 538
 539                 if (requestheader->msgtype ==
 540                     CHANNELMSG_INITIATE_CONTACT) {
 541                         initiate =
 542                         (struct vmbus_channel_initiate_contact *)requestheader;
 543                         memcpy(&msginfo->response.version_response,
 544                               version_response,
 545                               sizeof(struct vmbus_channel_version_response));
 546                         complete(&msginfo->waitevent);
 547                 }
 548         }
 549         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 550 }
 551
 552 /* Channel message dispatch table */
 553 static struct vmbus_channel_message_table_entry
 554         channel_message_table[CHANNELMSG_COUNT] = {
 555         {CHANNELMSG_INVALID,                    NULL},
 556         {CHANNELMSG_OFFERCHANNEL,               vmbus_onoffer},
 557         {CHANNELMSG_RESCIND_CHANNELOFFER,       vmbus_onoffer_rescind},
 558         {CHANNELMSG_REQUESTOFFERS,              NULL},
 559         {CHANNELMSG_ALLOFFERS_DELIVERED,        vmbus_onoffers_delivered},
 560         {CHANNELMSG_OPENCHANNEL,                NULL},
 561         {CHANNELMSG_OPENCHANNEL_RESULT, vmbus_onopen_result},
 562         {CHANNELMSG_CLOSECHANNEL,               NULL},
 563         {CHANNELMSG_GPADL_HEADER,               NULL},
 564         {CHANNELMSG_GPADL_BODY,         NULL},
 565         {CHANNELMSG_GPADL_CREATED,              vmbus_ongpadl_created},
 566         {CHANNELMSG_GPADL_TEARDOWN,             NULL},
 567         {CHANNELMSG_GPADL_TORNDOWN,             vmbus_ongpadl_torndown},
 568         {CHANNELMSG_RELID_RELEASED,             NULL},
 569         {CHANNELMSG_INITIATE_CONTACT,           NULL},
 570         {CHANNELMSG_VERSION_RESPONSE,           vmbus_onversion_response},
 571         {CHANNELMSG_UNLOAD,                     NULL},
 572 };
 573
 574 /*
 575  * vmbus_onmessage - Handler for channel protocol messages.
 576  *
 577  * This is invoked in the vmbus worker thread context.
 578  */
 579 void vmbus_onmessage(void *context)
 580 {
 581         struct hv_message *msg = context;
 582         struct vmbus_channel_message_header *hdr;
 583         int size;
 584
 585         hdr = (struct vmbus_channel_message_header *)msg->u.payload;
 586         size = msg->header.payload_size;
 587
 588         if (hdr->msgtype >= CHANNELMSG_COUNT) {
 589                 pr_err("Received invalid channel message type %d size %d\n",
 590                            hdr->msgtype, size);
 591                 print_hex_dump_bytes("", DUMP_PREFIX_NONE,
 592                                      (unsigned char *)msg->u.payload, size);
 593                 return;
 594         }
 595
 596         if (channel_message_table[hdr->msgtype].message_handler)
 597                 channel_message_table[hdr->msgtype].message_handler(hdr);
 598         else
 599                 pr_err("Unhandled channel message type %d\n", hdr->msgtype);
 600 }
 601
 602 /*
 603  * vmbus_request_offers - Send a request to get all our pending offers.
 604  */
 605 int vmbus_request_offers(void)
 606 {
 607         struct vmbus_channel_message_header *msg;
 608         struct vmbus_channel_msginfo *msginfo;
 609         int ret, t;
 610
 611         msginfo = kmalloc(sizeof(*msginfo) +
 612                           sizeof(struct vmbus_channel_message_header),
 613                           GFP_KERNEL);
 614         if (!msginfo)
 615                 return -ENOMEM;
 616
 617         init_completion(&msginfo->waitevent);
 618
 619         msg = (struct vmbus_channel_message_header *)msginfo->msg;
 620
 621         msg->msgtype = CHANNELMSG_REQUESTOFFERS;
 622
 623
 624         ret = vmbus_post_msg(msg,
 625                                sizeof(struct vmbus_channel_message_header));
 626         if (ret != 0) {
 627                 pr_err("Unable to request offers - %d\n", ret);
 628
 629                 goto cleanup;
 630         }
 631
 632         t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
 633         if (t == 0) {
 634                 ret = -ETIMEDOUT;
 635                 goto cleanup;
 636         }
 637
 638
 639
 640 cleanup:
 641         kfree(msginfo);
 642
 643         return ret;
 644 }
 645
 646 /* eof */