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         unsigned long flags;
 169         struct vmbus_channel_relid_released msg;
 170
 171         vmbus_device_unregister(channel->device_obj);
 172         memset(&msg, 0, sizeof(struct vmbus_channel_relid_released));
 173         msg.child_relid = channel->offermsg.child_relid;
 174         msg.header.msgtype = CHANNELMSG_RELID_RELEASED;
 175         vmbus_post_msg(&msg, sizeof(struct vmbus_channel_relid_released));
 176
 177         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 178         list_del(&channel->listentry);
 179         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 180         free_channel(channel);
 181 }
 182
 183 void vmbus_free_channels(void)
 184 {
 185         struct vmbus_channel *channel;
 186
 187         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 188                 vmbus_device_unregister(channel->device_obj);
 189                 kfree(channel->device_obj);
 190                 free_channel(channel);
 191         }
 192 }
 193
 194 /*
 195  * vmbus_process_offer - Process the offer by creating a channel/device
 196  * associated with this offer
 197  */
 198 static void vmbus_process_offer(struct work_struct *work)
 199 {
 200         struct vmbus_channel *newchannel = container_of(work,
 201                                                         struct vmbus_channel,
 202                                                         work);
 203         struct vmbus_channel *channel;
 204         bool fnew = true;
 205         int ret;
 206         unsigned long flags;
 207
 208         /* The next possible work is rescind handling */
 209         INIT_WORK(&newchannel->work, vmbus_process_rescind_offer);
 210
 211         /* Make sure this is a new offer */
 212         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 213
 214         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 215                 if (!uuid_le_cmp(channel->offermsg.offer.if_type,
 216                         newchannel->offermsg.offer.if_type) &&
 217                         !uuid_le_cmp(channel->offermsg.offer.if_instance,
 218                                 newchannel->offermsg.offer.if_instance)) {
 219                         fnew = false;
 220                         break;
 221                 }
 222         }
 223
 224         if (fnew)
 225                 list_add_tail(&newchannel->listentry,
 226                               &vmbus_connection.chn_list);
 227
 228         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 229
 230         if (!fnew) {
 231                 free_channel(newchannel);
 232                 return;
 233         }
 234
 235         /*
 236          * Start the process of binding this offer to the driver
 237          * We need to set the DeviceObject field before calling
 238          * vmbus_child_dev_add()
 239          */
 240         newchannel->device_obj = vmbus_device_create(
 241                 &newchannel->offermsg.offer.if_type,
 242                 &newchannel->offermsg.offer.if_instance,
 243                 newchannel);
 244
 245         /*
 246          * Add the new device to the bus. This will kick off device-driver
 247          * binding which eventually invokes the device driver's AddDevice()
 248          * method.
 249          */
 250         ret = vmbus_device_register(newchannel->device_obj);
 251         if (ret != 0) {
 252                 pr_err("unable to add child device object (relid %d)\n",
 253                            newchannel->offermsg.child_relid);
 254
 255                 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 256                 list_del(&newchannel->listentry);
 257                 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 258                 kfree(newchannel->device_obj);
 259
 260                 free_channel(newchannel);
 261         } else {
 262                 /*
 263                  * This state is used to indicate a successful open
 264                  * so that when we do close the channel normally, we
 265                  * can cleanup properly
 266                  */
 267                 newchannel->state = CHANNEL_OPEN_STATE;
 268         }
 269 }
 270
 271 enum {
 272         IDE = 0,
 273         SCSI,
 274         NIC,
 275         MAX_PERF_CHN,
 276 };
 277
 278 /*
 279  * This is an array of device_ids (device types) that are performance critical.
 280  * We attempt to distribute the interrupt load for these devices across
 281  * all available CPUs.
 282  */
 283 static const struct hv_vmbus_device_id hp_devs[] = {
 284         /* IDE */
 285         { HV_IDE_GUID, },
 286         /* Storage - SCSI */
 287         { HV_SCSI_GUID, },
 288         /* Network */
 289         { HV_NIC_GUID, },
 290 };
 291
 292
 293 /*
 294  * We use this state to statically distribute the channel interrupt load.
 295  */
 296 static u32  next_vp;
 297
 298 /*
 299  * Starting with Win8, we can statically distribute the incoming
 300  * channel interrupt load by binding a channel to VCPU. We
 301  * implement here a simple round robin scheme for distributing
 302  * the interrupt load.
 303  * We will bind channels that are not performance critical to cpu 0 and
 304  * performance critical channels (IDE, SCSI and Network) will be uniformly
 305  * distributed across all available CPUs.
 306  */
 307 static u32 get_vp_index(uuid_le *type_guid)
 308 {
 309         u32 cur_cpu;
 310         int i;
 311         bool perf_chn = false;
 312         u32 max_cpus = num_online_cpus();
 313
 314         for (i = IDE; i < MAX_PERF_CHN; i++) {
 315                 if (!memcmp(type_guid->b, hp_devs[i].guid,
 316                                  sizeof(uuid_le))) {
 317                         perf_chn = true;
 318                         break;
 319                 }
 320         }
 321         if ((vmbus_proto_version == VERSION_WS2008) ||
 322             (vmbus_proto_version == VERSION_WIN7) || (!perf_chn)) {
 323                 /*
 324                  * Prior to win8, all channel interrupts are
 325                  * delivered on cpu 0.
 326                  * Also if the channel is not a performance critical
 327                  * channel, bind it to cpu 0.
 328                  */
 329                 return 0;
 330         }
 331         cur_cpu = (++next_vp % max_cpus);
 332         return cur_cpu;
 333 }
 334
 335 /*
 336  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 337  *
 338  */
 339 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 340 {
 341         struct vmbus_channel_offer_channel *offer;
 342         struct vmbus_channel *newchannel;
 343
 344         offer = (struct vmbus_channel_offer_channel *)hdr;
 345
 346         /* Allocate the channel object and save this offer. */
 347         newchannel = alloc_channel();
 348         if (!newchannel) {
 349                 pr_err("Unable to allocate channel object\n");
 350                 return;
 351         }
 352
 353         /*
 354          * By default we setup state to enable batched
 355          * reading. A specific service can choose to
 356          * disable this prior to opening the channel.
 357          */
 358         newchannel->batched_reading = true;
 359
 360         /*
 361          * Setup state for signalling the host.
 362          */
 363         newchannel->sig_event = (struct hv_input_signal_event *)
 364                                 (ALIGN((unsigned long)
 365                                 &newchannel->sig_buf,
 366                                 HV_HYPERCALL_PARAM_ALIGN));
 367
 368         newchannel->sig_event->connectionid.asu32 = 0;
 369         newchannel->sig_event->connectionid.u.id = VMBUS_EVENT_CONNECTION_ID;
 370         newchannel->sig_event->flag_number = 0;
 371         newchannel->sig_event->rsvdz = 0;
 372
 373         if (vmbus_proto_version != VERSION_WS2008) {
 374                 newchannel->is_dedicated_interrupt =
 375                                 (offer->is_dedicated_interrupt != 0);
 376                 newchannel->sig_event->connectionid.u.id =
 377                                 offer->connection_id;
 378         }
 379
 380         newchannel->target_vp = get_vp_index(&offer->offer.if_type);
 381
 382         memcpy(&newchannel->offermsg, offer,
 383                sizeof(struct vmbus_channel_offer_channel));
 384         newchannel->monitor_grp = (u8)offer->monitorid / 32;
 385         newchannel->monitor_bit = (u8)offer->monitorid % 32;
 386
 387         INIT_WORK(&newchannel->work, vmbus_process_offer);
 388         queue_work(newchannel->controlwq, &newchannel->work);
 389 }
 390
 391 /*
 392  * vmbus_onoffer_rescind - Rescind offer handler.
 393  *
 394  * We queue a work item to process this offer synchronously
 395  */
 396 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 397 {
 398         struct vmbus_channel_rescind_offer *rescind;
 399         struct vmbus_channel *channel;
 400
 401         rescind = (struct vmbus_channel_rescind_offer *)hdr;
 402         channel = relid2channel(rescind->child_relid);
 403
 404         if (channel == NULL)
 405                 /* Just return here, no channel found */
 406                 return;
 407
 408         /* work is initialized for vmbus_process_rescind_offer() from
 409          * vmbus_process_offer() where the channel got created */
 410         queue_work(channel->controlwq, &channel->work);
 411 }
 412
 413 /*
 414  * vmbus_onoffers_delivered -
 415  * This is invoked when all offers have been delivered.
 416  *
 417  * Nothing to do here.
 418  */
 419 static void vmbus_onoffers_delivered(
 420                         struct vmbus_channel_message_header *hdr)
 421 {
 422 }
 423
 424 /*
 425  * vmbus_onopen_result - Open result handler.
 426  *
 427  * This is invoked when we received a response to our channel open request.
 428  * Find the matching request, copy the response and signal the requesting
 429  * thread.
 430  */
 431 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
 432 {
 433         struct vmbus_channel_open_result *result;
 434         struct vmbus_channel_msginfo *msginfo;
 435         struct vmbus_channel_message_header *requestheader;
 436         struct vmbus_channel_open_channel *openmsg;
 437         unsigned long flags;
 438
 439         result = (struct vmbus_channel_open_result *)hdr;
 440
 441         /*
 442          * Find the open msg, copy the result and signal/unblock the wait 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_OPENCHANNEL) {
 452                         openmsg =
 453                         (struct vmbus_channel_open_channel *)msginfo->msg;
 454                         if (openmsg->child_relid == result->child_relid &&
 455                             openmsg->openid == result->openid) {
 456                                 memcpy(&msginfo->response.open_result,
 457                                        result,
 458                                        sizeof(
 459                                         struct vmbus_channel_open_result));
 460                                 complete(&msginfo->waitevent);
 461                                 break;
 462                         }
 463                 }
 464         }
 465         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 466 }
 467
 468 /*
 469  * vmbus_ongpadl_created - GPADL created handler.
 470  *
 471  * This is invoked when we received a response to our gpadl create request.
 472  * Find the matching request, copy the response and signal the requesting
 473  * thread.
 474  */
 475 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
 476 {
 477         struct vmbus_channel_gpadl_created *gpadlcreated;
 478         struct vmbus_channel_msginfo *msginfo;
 479         struct vmbus_channel_message_header *requestheader;
 480         struct vmbus_channel_gpadl_header *gpadlheader;
 481         unsigned long flags;
 482
 483         gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
 484
 485         /*
 486          * Find the establish msg, copy the result and signal/unblock the wait
 487          * event
 488          */
 489         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 490
 491         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 492                                 msglistentry) {
 493                 requestheader =
 494                         (struct vmbus_channel_message_header *)msginfo->msg;
 495
 496                 if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
 497                         gpadlheader =
 498                         (struct vmbus_channel_gpadl_header *)requestheader;
 499
 500                         if ((gpadlcreated->child_relid ==
 501                              gpadlheader->child_relid) &&
 502                             (gpadlcreated->gpadl == gpadlheader->gpadl)) {
 503                                 memcpy(&msginfo->response.gpadl_created,
 504                                        gpadlcreated,
 505                                        sizeof(
 506                                         struct vmbus_channel_gpadl_created));
 507                                 complete(&msginfo->waitevent);
 508                                 break;
 509                         }
 510                 }
 511         }
 512         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 513 }
 514
 515 /*
 516  * vmbus_ongpadl_torndown - GPADL torndown handler.
 517  *
 518  * This is invoked when we received a response to our gpadl teardown request.
 519  * Find the matching request, copy the response and signal the requesting
 520  * thread.
 521  */
 522 static void vmbus_ongpadl_torndown(
 523                         struct vmbus_channel_message_header *hdr)
 524 {
 525         struct vmbus_channel_gpadl_torndown *gpadl_torndown;
 526         struct vmbus_channel_msginfo *msginfo;
 527         struct vmbus_channel_message_header *requestheader;
 528         struct vmbus_channel_gpadl_teardown *gpadl_teardown;
 529         unsigned long flags;
 530
 531         gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
 532
 533         /*
 534          * Find the open msg, copy the result and signal/unblock the wait event
 535          */
 536         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 537
 538         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 539                                 msglistentry) {
 540                 requestheader =
 541                         (struct vmbus_channel_message_header *)msginfo->msg;
 542
 543                 if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
 544                         gpadl_teardown =
 545                         (struct vmbus_channel_gpadl_teardown *)requestheader;
 546
 547                         if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
 548                                 memcpy(&msginfo->response.gpadl_torndown,
 549                                        gpadl_torndown,
 550                                        sizeof(
 551                                         struct vmbus_channel_gpadl_torndown));
 552                                 complete(&msginfo->waitevent);
 553                                 break;
 554                         }
 555                 }
 556         }
 557         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 558 }
 559
 560 /*
 561  * vmbus_onversion_response - Version response handler
 562  *
 563  * This is invoked when we received a response to our initiate contact request.
 564  * Find the matching request, copy the response and signal the requesting
 565  * thread.
 566  */
 567 static void vmbus_onversion_response(
 568                 struct vmbus_channel_message_header *hdr)
 569 {
 570         struct vmbus_channel_msginfo *msginfo;
 571         struct vmbus_channel_message_header *requestheader;
 572         struct vmbus_channel_version_response *version_response;
 573         unsigned long flags;
 574
 575         version_response = (struct vmbus_channel_version_response *)hdr;
 576         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 577
 578         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 579                                 msglistentry) {
 580                 requestheader =
 581                         (struct vmbus_channel_message_header *)msginfo->msg;
 582
 583                 if (requestheader->msgtype ==
 584                     CHANNELMSG_INITIATE_CONTACT) {
 585                         memcpy(&msginfo->response.version_response,
 586                               version_response,
 587                               sizeof(struct vmbus_channel_version_response));
 588                         complete(&msginfo->waitevent);
 589                 }
 590         }
 591         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 592 }
 593
 594 /* Channel message dispatch table */
 595 static struct vmbus_channel_message_table_entry
 596         channel_message_table[CHANNELMSG_COUNT] = {
 597         {CHANNELMSG_INVALID,                    NULL},
 598         {CHANNELMSG_OFFERCHANNEL,               vmbus_onoffer},
 599         {CHANNELMSG_RESCIND_CHANNELOFFER,       vmbus_onoffer_rescind},
 600         {CHANNELMSG_REQUESTOFFERS,              NULL},
 601         {CHANNELMSG_ALLOFFERS_DELIVERED,        vmbus_onoffers_delivered},
 602         {CHANNELMSG_OPENCHANNEL,                NULL},
 603         {CHANNELMSG_OPENCHANNEL_RESULT, vmbus_onopen_result},
 604         {CHANNELMSG_CLOSECHANNEL,               NULL},
 605         {CHANNELMSG_GPADL_HEADER,               NULL},
 606         {CHANNELMSG_GPADL_BODY,         NULL},
 607         {CHANNELMSG_GPADL_CREATED,              vmbus_ongpadl_created},
 608         {CHANNELMSG_GPADL_TEARDOWN,             NULL},
 609         {CHANNELMSG_GPADL_TORNDOWN,             vmbus_ongpadl_torndown},
 610         {CHANNELMSG_RELID_RELEASED,             NULL},
 611         {CHANNELMSG_INITIATE_CONTACT,           NULL},
 612         {CHANNELMSG_VERSION_RESPONSE,           vmbus_onversion_response},
 613         {CHANNELMSG_UNLOAD,                     NULL},
 614 };
 615
 616 /*
 617  * vmbus_onmessage - Handler for channel protocol messages.
 618  *
 619  * This is invoked in the vmbus worker thread context.
 620  */
 621 void vmbus_onmessage(void *context)
 622 {
 623         struct hv_message *msg = context;
 624         struct vmbus_channel_message_header *hdr;
 625         int size;
 626
 627         hdr = (struct vmbus_channel_message_header *)msg->u.payload;
 628         size = msg->header.payload_size;
 629
 630         if (hdr->msgtype >= CHANNELMSG_COUNT) {
 631                 pr_err("Received invalid channel message type %d size %d\n",
 632                            hdr->msgtype, size);
 633                 print_hex_dump_bytes("", DUMP_PREFIX_NONE,
 634                                      (unsigned char *)msg->u.payload, size);
 635                 return;
 636         }
 637
 638         if (channel_message_table[hdr->msgtype].message_handler)
 639                 channel_message_table[hdr->msgtype].message_handler(hdr);
 640         else
 641                 pr_err("Unhandled channel message type %d\n", hdr->msgtype);
 642 }
 643
 644 /*
 645  * vmbus_request_offers - Send a request to get all our pending offers.
 646  */
 647 int vmbus_request_offers(void)
 648 {
 649         struct vmbus_channel_message_header *msg;
 650         struct vmbus_channel_msginfo *msginfo;
 651         int ret, t;
 652
 653         msginfo = kmalloc(sizeof(*msginfo) +
 654                           sizeof(struct vmbus_channel_message_header),
 655                           GFP_KERNEL);
 656         if (!msginfo)
 657                 return -ENOMEM;
 658
 659         init_completion(&msginfo->waitevent);
 660
 661         msg = (struct vmbus_channel_message_header *)msginfo->msg;
 662
 663         msg->msgtype = CHANNELMSG_REQUESTOFFERS;
 664
 665
 666         ret = vmbus_post_msg(msg,
 667                                sizeof(struct vmbus_channel_message_header));
 668         if (ret != 0) {
 669                 pr_err("Unable to request offers - %d\n", ret);
 670
 671                 goto cleanup;
 672         }
 673
 674         t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
 675         if (t == 0) {
 676                 ret = -ETIMEDOUT;
 677                 goto cleanup;
 678         }
 679
 680
 681
 682 cleanup:
 683         kfree(msginfo);
 684
 685         return ret;
 686 }
 687
 688 /* eof */