drivers/hv/channel.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/module.h>
  29 #include <linux/hyperv.h>
  30 #include <linux/uio.h>
  31 #include <linux/interrupt.h>
  32
  33 #include "hyperv_vmbus.h"
  34
  35 #define NUM_PAGES_SPANNED(addr, len) \
  36 ((PAGE_ALIGN(addr + len) >> PAGE_SHIFT) - (addr >> PAGE_SHIFT))
  37
  38 /*
  39  * vmbus_setevent- Trigger an event notification on the specified
  40  * channel.
  41  */
  42 void vmbus_setevent(struct vmbus_channel *channel)
  43 {
  44         struct hv_monitor_page *monitorpage;
  45
  46         trace_vmbus_setevent(channel);
  47
  48         /*
  49          * For channels marked as in "low latency" mode
  50          * bypass the monitor page mechanism.
  51          */
  52         if (channel->offermsg.monitor_allocated && !channel->low_latency) {
  53                 vmbus_send_interrupt(channel->offermsg.child_relid);
  54
  55                 /* Get the child to parent monitor page */
  56                 monitorpage = vmbus_connection.monitor_pages[1];
  57
  58                 sync_set_bit(channel->monitor_bit,
  59                         (unsigned long *)&monitorpage->trigger_group
  60                                         [channel->monitor_grp].pending);
  61
  62         } else {
  63                 vmbus_set_event(channel);
  64         }
  65 }
  66 EXPORT_SYMBOL_GPL(vmbus_setevent);
  67
  68 /*
  69  * vmbus_open - Open the specified channel.
  70  */
  71 int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
  72                      u32 recv_ringbuffer_size, void *userdata, u32 userdatalen,
  73                      void (*onchannelcallback)(void *context), void *context)
  74 {
  75         struct vmbus_channel_open_channel *open_msg;
  76         struct vmbus_channel_msginfo *open_info = NULL;
  77         unsigned long flags;
  78         int ret, err = 0;
  79         struct page *page;
  80
  81         if (send_ringbuffer_size % PAGE_SIZE ||
  82             recv_ringbuffer_size % PAGE_SIZE)
  83                 return -EINVAL;
  84
  85         spin_lock_irqsave(&newchannel->lock, flags);
  86         if (newchannel->state == CHANNEL_OPEN_STATE) {
  87                 newchannel->state = CHANNEL_OPENING_STATE;
  88         } else {
  89                 spin_unlock_irqrestore(&newchannel->lock, flags);
  90                 return -EINVAL;
  91         }
  92         spin_unlock_irqrestore(&newchannel->lock, flags);
  93
  94         newchannel->onchannel_callback = onchannelcallback;
  95         newchannel->channel_callback_context = context;
  96
  97         /* Allocate the ring buffer */
  98         page = alloc_pages_node(cpu_to_node(newchannel->target_cpu),
  99                                 GFP_KERNEL|__GFP_ZERO,
 100                                 get_order(send_ringbuffer_size +
 101                                 recv_ringbuffer_size));
 102
 103         if (!page)
 104                 page = alloc_pages(GFP_KERNEL|__GFP_ZERO,
 105                                    get_order(send_ringbuffer_size +
 106                                              recv_ringbuffer_size));
 107
 108         if (!page) {
 109                 err = -ENOMEM;
 110                 goto error_set_chnstate;
 111         }
 112
 113         newchannel->ringbuffer_pages = page_address(page);
 114         newchannel->ringbuffer_pagecount = (send_ringbuffer_size +
 115                                            recv_ringbuffer_size) >> PAGE_SHIFT;
 116
 117         ret = hv_ringbuffer_init(&newchannel->outbound, page,
 118                                  send_ringbuffer_size >> PAGE_SHIFT);
 119
 120         if (ret != 0) {
 121                 err = ret;
 122                 goto error_free_pages;
 123         }
 124
 125         ret = hv_ringbuffer_init(&newchannel->inbound,
 126                                  &page[send_ringbuffer_size >> PAGE_SHIFT],
 127                                  recv_ringbuffer_size >> PAGE_SHIFT);
 128         if (ret != 0) {
 129                 err = ret;
 130                 goto error_free_pages;
 131         }
 132
 133
 134         /* Establish the gpadl for the ring buffer */
 135         newchannel->ringbuffer_gpadlhandle = 0;
 136
 137         ret = vmbus_establish_gpadl(newchannel,
 138                                     page_address(page),
 139                                     send_ringbuffer_size +
 140                                     recv_ringbuffer_size,
 141                                     &newchannel->ringbuffer_gpadlhandle);
 142
 143         if (ret != 0) {
 144                 err = ret;
 145                 goto error_free_pages;
 146         }
 147
 148         /* Create and init the channel open message */
 149         open_info = kmalloc(sizeof(*open_info) +
 150                            sizeof(struct vmbus_channel_open_channel),
 151                            GFP_KERNEL);
 152         if (!open_info) {
 153                 err = -ENOMEM;
 154                 goto error_free_gpadl;
 155         }
 156
 157         init_completion(&open_info->waitevent);
 158         open_info->waiting_channel = newchannel;
 159
 160         open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
 161         open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
 162         open_msg->openid = newchannel->offermsg.child_relid;
 163         open_msg->child_relid = newchannel->offermsg.child_relid;
 164         open_msg->ringbuffer_gpadlhandle = newchannel->ringbuffer_gpadlhandle;
 165         open_msg->downstream_ringbuffer_pageoffset = send_ringbuffer_size >>
 166                                                   PAGE_SHIFT;
 167         open_msg->target_vp = newchannel->target_vp;
 168
 169         if (userdatalen > MAX_USER_DEFINED_BYTES) {
 170                 err = -EINVAL;
 171                 goto error_free_gpadl;
 172         }
 173
 174         if (userdatalen)
 175                 memcpy(open_msg->userdata, userdata, userdatalen);
 176
 177         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 178         list_add_tail(&open_info->msglistentry,
 179                       &vmbus_connection.chn_msg_list);
 180         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 181
 182         if (newchannel->rescind) {
 183                 err = -ENODEV;
 184                 goto error_free_gpadl;
 185         }
 186
 187         ret = vmbus_post_msg(open_msg,
 188                              sizeof(struct vmbus_channel_open_channel), true);
 189
 190         trace_vmbus_open(open_msg, ret);
 191
 192         if (ret != 0) {
 193                 err = ret;
 194                 goto error_clean_msglist;
 195         }
 196
 197         wait_for_completion(&open_info->waitevent);
 198
 199         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 200         list_del(&open_info->msglistentry);
 201         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 202
 203         if (newchannel->rescind) {
 204                 err = -ENODEV;
 205                 goto error_free_gpadl;
 206         }
 207
 208         if (open_info->response.open_result.status) {
 209                 err = -EAGAIN;
 210                 goto error_free_gpadl;
 211         }
 212
 213         newchannel->state = CHANNEL_OPENED_STATE;
 214         kfree(open_info);
 215         return 0;
 216
 217 error_clean_msglist:
 218         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 219         list_del(&open_info->msglistentry);
 220         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 221
 222 error_free_gpadl:
 223         vmbus_teardown_gpadl(newchannel, newchannel->ringbuffer_gpadlhandle);
 224         kfree(open_info);
 225 error_free_pages:
 226         hv_ringbuffer_cleanup(&newchannel->outbound);
 227         hv_ringbuffer_cleanup(&newchannel->inbound);
 228         __free_pages(page,
 229                      get_order(send_ringbuffer_size + recv_ringbuffer_size));
 230 error_set_chnstate:
 231         newchannel->state = CHANNEL_OPEN_STATE;
 232         return err;
 233 }
 234 EXPORT_SYMBOL_GPL(vmbus_open);
 235
 236 /* Used for Hyper-V Socket: a guest client's connect() to the host */
 237 int vmbus_send_tl_connect_request(const uuid_le *shv_guest_servie_id,
 238                                   const uuid_le *shv_host_servie_id)
 239 {
 240         struct vmbus_channel_tl_connect_request conn_msg;
 241         int ret;
 242
 243         memset(&conn_msg, 0, sizeof(conn_msg));
 244         conn_msg.header.msgtype = CHANNELMSG_TL_CONNECT_REQUEST;
 245         conn_msg.guest_endpoint_id = *shv_guest_servie_id;
 246         conn_msg.host_service_id = *shv_host_servie_id;
 247
 248         ret = vmbus_post_msg(&conn_msg, sizeof(conn_msg), true);
 249
 250         trace_vmbus_send_tl_connect_request(&conn_msg, ret);
 251
 252         return ret;
 253 }
 254 EXPORT_SYMBOL_GPL(vmbus_send_tl_connect_request);
 255
 256 /*
 257  * create_gpadl_header - Creates a gpadl for the specified buffer
 258  */
 259 static int create_gpadl_header(void *kbuffer, u32 size,
 260                                struct vmbus_channel_msginfo **msginfo)
 261 {
 262         int i;
 263         int pagecount;
 264         struct vmbus_channel_gpadl_header *gpadl_header;
 265         struct vmbus_channel_gpadl_body *gpadl_body;
 266         struct vmbus_channel_msginfo *msgheader;
 267         struct vmbus_channel_msginfo *msgbody = NULL;
 268         u32 msgsize;
 269
 270         int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
 271
 272         pagecount = size >> PAGE_SHIFT;
 273
 274         /* do we need a gpadl body msg */
 275         pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 276                   sizeof(struct vmbus_channel_gpadl_header) -
 277                   sizeof(struct gpa_range);
 278         pfncount = pfnsize / sizeof(u64);
 279
 280         if (pagecount > pfncount) {
 281                 /* we need a gpadl body */
 282                 /* fill in the header */
 283                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 284                           sizeof(struct vmbus_channel_gpadl_header) +
 285                           sizeof(struct gpa_range) + pfncount * sizeof(u64);
 286                 msgheader =  kzalloc(msgsize, GFP_KERNEL);
 287                 if (!msgheader)
 288                         goto nomem;
 289
 290                 INIT_LIST_HEAD(&msgheader->submsglist);
 291                 msgheader->msgsize = msgsize;
 292
 293                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 294                         msgheader->msg;
 295                 gpadl_header->rangecount = 1;
 296                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 297                                          pagecount * sizeof(u64);
 298                 gpadl_header->range[0].byte_offset = 0;
 299                 gpadl_header->range[0].byte_count = size;
 300                 for (i = 0; i < pfncount; i++)
 301                         gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
 302                                 kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 303                 *msginfo = msgheader;
 304
 305                 pfnsum = pfncount;
 306                 pfnleft = pagecount - pfncount;
 307
 308                 /* how many pfns can we fit */
 309                 pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 310                           sizeof(struct vmbus_channel_gpadl_body);
 311                 pfncount = pfnsize / sizeof(u64);
 312
 313                 /* fill in the body */
 314                 while (pfnleft) {
 315                         if (pfnleft > pfncount)
 316                                 pfncurr = pfncount;
 317                         else
 318                                 pfncurr = pfnleft;
 319
 320                         msgsize = sizeof(struct vmbus_channel_msginfo) +
 321                                   sizeof(struct vmbus_channel_gpadl_body) +
 322                                   pfncurr * sizeof(u64);
 323                         msgbody = kzalloc(msgsize, GFP_KERNEL);
 324
 325                         if (!msgbody) {
 326                                 struct vmbus_channel_msginfo *pos = NULL;
 327                                 struct vmbus_channel_msginfo *tmp = NULL;
 328                                 /*
 329                                  * Free up all the allocated messages.
 330                                  */
 331                                 list_for_each_entry_safe(pos, tmp,
 332                                         &msgheader->submsglist,
 333                                         msglistentry) {
 334
 335                                         list_del(&pos->msglistentry);
 336                                         kfree(pos);
 337                                 }
 338
 339                                 goto nomem;
 340                         }
 341
 342                         msgbody->msgsize = msgsize;
 343                         gpadl_body =
 344                                 (struct vmbus_channel_gpadl_body *)msgbody->msg;
 345
 346                         /*
 347                          * Gpadl is u32 and we are using a pointer which could
 348                          * be 64-bit
 349                          * This is governed by the guest/host protocol and
 350                          * so the hypervisor guarantees that this is ok.
 351                          */
 352                         for (i = 0; i < pfncurr; i++)
 353                                 gpadl_body->pfn[i] = slow_virt_to_phys(
 354                                         kbuffer + PAGE_SIZE * (pfnsum + i)) >>
 355                                         PAGE_SHIFT;
 356
 357                         /* add to msg header */
 358                         list_add_tail(&msgbody->msglistentry,
 359                                       &msgheader->submsglist);
 360                         pfnsum += pfncurr;
 361                         pfnleft -= pfncurr;
 362                 }
 363         } else {
 364                 /* everything fits in a header */
 365                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 366                           sizeof(struct vmbus_channel_gpadl_header) +
 367                           sizeof(struct gpa_range) + pagecount * sizeof(u64);
 368                 msgheader = kzalloc(msgsize, GFP_KERNEL);
 369                 if (msgheader == NULL)
 370                         goto nomem;
 371
 372                 INIT_LIST_HEAD(&msgheader->submsglist);
 373                 msgheader->msgsize = msgsize;
 374
 375                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 376                         msgheader->msg;
 377                 gpadl_header->rangecount = 1;
 378                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 379                                          pagecount * sizeof(u64);
 380                 gpadl_header->range[0].byte_offset = 0;
 381                 gpadl_header->range[0].byte_count = size;
 382                 for (i = 0; i < pagecount; i++)
 383                         gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
 384                                 kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 385
 386                 *msginfo = msgheader;
 387         }
 388
 389         return 0;
 390 nomem:
 391         kfree(msgheader);
 392         kfree(msgbody);
 393         return -ENOMEM;
 394 }
 395
 396 /*
 397  * vmbus_establish_gpadl - Establish a GPADL for the specified buffer
 398  *
 399  * @channel: a channel
 400  * @kbuffer: from kmalloc or vmalloc
 401  * @size: page-size multiple
 402  * @gpadl_handle: some funky thing
 403  */
 404 int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
 405                                u32 size, u32 *gpadl_handle)
 406 {
 407         struct vmbus_channel_gpadl_header *gpadlmsg;
 408         struct vmbus_channel_gpadl_body *gpadl_body;
 409         struct vmbus_channel_msginfo *msginfo = NULL;
 410         struct vmbus_channel_msginfo *submsginfo, *tmp;
 411         struct list_head *curr;
 412         u32 next_gpadl_handle;
 413         unsigned long flags;
 414         int ret = 0;
 415
 416         next_gpadl_handle =
 417                 (atomic_inc_return(&vmbus_connection.next_gpadl_handle) - 1);
 418
 419         ret = create_gpadl_header(kbuffer, size, &msginfo);
 420         if (ret)
 421                 return ret;
 422
 423         init_completion(&msginfo->waitevent);
 424         msginfo->waiting_channel = channel;
 425
 426         gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
 427         gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
 428         gpadlmsg->child_relid = channel->offermsg.child_relid;
 429         gpadlmsg->gpadl = next_gpadl_handle;
 430
 431
 432         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 433         list_add_tail(&msginfo->msglistentry,
 434                       &vmbus_connection.chn_msg_list);
 435
 436         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 437
 438         if (channel->rescind) {
 439                 ret = -ENODEV;
 440                 goto cleanup;
 441         }
 442
 443         ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize -
 444                              sizeof(*msginfo), true);
 445
 446         trace_vmbus_establish_gpadl_header(gpadlmsg, ret);
 447
 448         if (ret != 0)
 449                 goto cleanup;
 450
 451         list_for_each(curr, &msginfo->submsglist) {
 452                 submsginfo = (struct vmbus_channel_msginfo *)curr;
 453                 gpadl_body =
 454                         (struct vmbus_channel_gpadl_body *)submsginfo->msg;
 455
 456                 gpadl_body->header.msgtype =
 457                         CHANNELMSG_GPADL_BODY;
 458                 gpadl_body->gpadl = next_gpadl_handle;
 459
 460                 ret = vmbus_post_msg(gpadl_body,
 461                                      submsginfo->msgsize - sizeof(*submsginfo),
 462                                      true);
 463
 464                 trace_vmbus_establish_gpadl_body(gpadl_body, ret);
 465
 466                 if (ret != 0)
 467                         goto cleanup;
 468
 469         }
 470         wait_for_completion(&msginfo->waitevent);
 471
 472         if (channel->rescind) {
 473                 ret = -ENODEV;
 474                 goto cleanup;
 475         }
 476
 477         /* At this point, we received the gpadl created msg */
 478         *gpadl_handle = gpadlmsg->gpadl;
 479
 480 cleanup:
 481         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 482         list_del(&msginfo->msglistentry);
 483         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 484         list_for_each_entry_safe(submsginfo, tmp, &msginfo->submsglist,
 485                                  msglistentry) {
 486                 kfree(submsginfo);
 487         }
 488
 489         kfree(msginfo);
 490         return ret;
 491 }
 492 EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
 493
 494 /*
 495  * vmbus_teardown_gpadl -Teardown the specified GPADL handle
 496  */
 497 int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
 498 {
 499         struct vmbus_channel_gpadl_teardown *msg;
 500         struct vmbus_channel_msginfo *info;
 501         unsigned long flags;
 502         int ret;
 503
 504         info = kmalloc(sizeof(*info) +
 505                        sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
 506         if (!info)
 507                 return -ENOMEM;
 508
 509         init_completion(&info->waitevent);
 510         info->waiting_channel = channel;
 511
 512         msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
 513
 514         msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
 515         msg->child_relid = channel->offermsg.child_relid;
 516         msg->gpadl = gpadl_handle;
 517
 518         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 519         list_add_tail(&info->msglistentry,
 520                       &vmbus_connection.chn_msg_list);
 521         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 522
 523         if (channel->rescind)
 524                 goto post_msg_err;
 525
 526         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_gpadl_teardown),
 527                              true);
 528
 529         trace_vmbus_teardown_gpadl(msg, ret);
 530
 531         if (ret)
 532                 goto post_msg_err;
 533
 534         wait_for_completion(&info->waitevent);
 535
 536 post_msg_err:
 537         /*
 538          * If the channel has been rescinded;
 539          * we will be awakened by the rescind
 540          * handler; set the error code to zero so we don't leak memory.
 541          */
 542         if (channel->rescind)
 543                 ret = 0;
 544
 545         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 546         list_del(&info->msglistentry);
 547         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 548
 549         kfree(info);
 550         return ret;
 551 }
 552 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
 553
 554 static void reset_channel_cb(void *arg)
 555 {
 556         struct vmbus_channel *channel = arg;
 557
 558         channel->onchannel_callback = NULL;
 559 }
 560
 561 static int vmbus_close_internal(struct vmbus_channel *channel)
 562 {
 563         struct vmbus_channel_close_channel *msg;
 564         int ret;
 565
 566         /*
 567          * vmbus_on_event(), running in the per-channel tasklet, can race
 568          * with vmbus_close_internal() in the case of SMP guest, e.g., when
 569          * the former is accessing channel->inbound.ring_buffer, the latter
 570          * could be freeing the ring_buffer pages, so here we must stop it
 571          * first.
 572          */
 573         tasklet_disable(&channel->callback_event);
 574
 575         /*
 576          * In case a device driver's probe() fails (e.g.,
 577          * util_probe() -> vmbus_open() returns -ENOMEM) and the device is
 578          * rescinded later (e.g., we dynamically disable an Integrated Service
 579          * in Hyper-V Manager), the driver's remove() invokes vmbus_close():
 580          * here we should skip most of the below cleanup work.
 581          */
 582         if (channel->state != CHANNEL_OPENED_STATE) {
 583                 ret = -EINVAL;
 584                 goto out;
 585         }
 586
 587         channel->state = CHANNEL_OPEN_STATE;
 588         channel->sc_creation_callback = NULL;
 589         /* Stop callback and cancel the timer asap */
 590         if (channel->target_cpu != get_cpu()) {
 591                 put_cpu();
 592                 smp_call_function_single(channel->target_cpu, reset_channel_cb,
 593                                          channel, true);
 594         } else {
 595                 reset_channel_cb(channel);
 596                 put_cpu();
 597         }
 598
 599         /* Send a closing message */
 600
 601         msg = &channel->close_msg.msg;
 602
 603         msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
 604         msg->child_relid = channel->offermsg.child_relid;
 605
 606         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel),
 607                              true);
 608
 609         trace_vmbus_close_internal(msg, ret);
 610
 611         if (ret) {
 612                 pr_err("Close failed: close post msg return is %d\n", ret);
 613                 /*
 614                  * If we failed to post the close msg,
 615                  * it is perhaps better to leak memory.
 616                  */
 617                 goto out;
 618         }
 619
 620         /* Tear down the gpadl for the channel's ring buffer */
 621         if (channel->ringbuffer_gpadlhandle) {
 622                 ret = vmbus_teardown_gpadl(channel,
 623                                            channel->ringbuffer_gpadlhandle);
 624                 if (ret) {
 625                         pr_err("Close failed: teardown gpadl return %d\n", ret);
 626                         /*
 627                          * If we failed to teardown gpadl,
 628                          * it is perhaps better to leak memory.
 629                          */
 630                         goto out;
 631                 }
 632         }
 633
 634         /* Cleanup the ring buffers for this channel */
 635         hv_ringbuffer_cleanup(&channel->outbound);
 636         hv_ringbuffer_cleanup(&channel->inbound);
 637
 638         free_pages((unsigned long)channel->ringbuffer_pages,
 639                 get_order(channel->ringbuffer_pagecount * PAGE_SIZE));
 640
 641 out:
 642         /* re-enable tasklet for use on re-open */
 643         tasklet_enable(&channel->callback_event);
 644         return ret;
 645 }
 646
 647 /*
 648  * vmbus_close - Close the specified channel
 649  */
 650 void vmbus_close(struct vmbus_channel *channel)
 651 {
 652         struct list_head *cur, *tmp;
 653         struct vmbus_channel *cur_channel;
 654
 655         if (channel->primary_channel != NULL) {
 656                 /*
 657                  * We will only close sub-channels when
 658                  * the primary is closed.
 659                  */
 660                 return;
 661         }
 662         /*
 663          * Close all the sub-channels first and then close the
 664          * primary channel.
 665          */
 666         list_for_each_safe(cur, tmp, &channel->sc_list) {
 667                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 668                 if (cur_channel->rescind) {
 669                         wait_for_completion(&cur_channel->rescind_event);
 670                         mutex_lock(&vmbus_connection.channel_mutex);
 671                         vmbus_close_internal(cur_channel);
 672                         hv_process_channel_removal(
 673                                            cur_channel->offermsg.child_relid);
 674                 } else {
 675                         mutex_lock(&vmbus_connection.channel_mutex);
 676                         vmbus_close_internal(cur_channel);
 677                 }
 678                 mutex_unlock(&vmbus_connection.channel_mutex);
 679         }
 680         /*
 681          * Now close the primary.
 682          */
 683         mutex_lock(&vmbus_connection.channel_mutex);
 684         vmbus_close_internal(channel);
 685         mutex_unlock(&vmbus_connection.channel_mutex);
 686 }
 687 EXPORT_SYMBOL_GPL(vmbus_close);
 688
 689 /**
 690  * vmbus_sendpacket() - Send the specified buffer on the given channel
 691  * @channel: Pointer to vmbus_channel structure.
 692  * @buffer: Pointer to the buffer you want to receive the data into.
 693  * @bufferlen: Maximum size of what the the buffer will hold
 694  * @requestid: Identifier of the request
 695  * @type: Type of packet that is being send e.g. negotiate, time
 696  * packet etc.
 697  *
 698  * Sends data in @buffer directly to hyper-v via the vmbus
 699  * This will send the data unparsed to hyper-v.
 700  *
 701  * Mainly used by Hyper-V drivers.
 702  */
 703 int vmbus_sendpacket(struct vmbus_channel *channel, void *buffer,
 704                            u32 bufferlen, u64 requestid,
 705                            enum vmbus_packet_type type, u32 flags)
 706 {
 707         struct vmpacket_descriptor desc;
 708         u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
 709         u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 710         struct kvec bufferlist[3];
 711         u64 aligned_data = 0;
 712         int num_vecs = ((bufferlen != 0) ? 3 : 1);
 713
 714
 715         /* Setup the descriptor */
 716         desc.type = type; /* VmbusPacketTypeDataInBand; */
 717         desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
 718         /* in 8-bytes granularity */
 719         desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3;
 720         desc.len8 = (u16)(packetlen_aligned >> 3);
 721         desc.trans_id = requestid;
 722
 723         bufferlist[0].iov_base = &desc;
 724         bufferlist[0].iov_len = sizeof(struct vmpacket_descriptor);
 725         bufferlist[1].iov_base = buffer;
 726         bufferlist[1].iov_len = bufferlen;
 727         bufferlist[2].iov_base = &aligned_data;
 728         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 729
 730         return hv_ringbuffer_write(channel, bufferlist, num_vecs);
 731 }
 732 EXPORT_SYMBOL(vmbus_sendpacket);
 733
 734 /*
 735  * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
 736  * packets using a GPADL Direct packet type. This interface allows you
 737  * to control notifying the host. This will be useful for sending
 738  * batched data. Also the sender can control the send flags
 739  * explicitly.
 740  */
 741 int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
 742                                 struct hv_page_buffer pagebuffers[],
 743                                 u32 pagecount, void *buffer, u32 bufferlen,
 744                                 u64 requestid)
 745 {
 746         int i;
 747         struct vmbus_channel_packet_page_buffer desc;
 748         u32 descsize;
 749         u32 packetlen;
 750         u32 packetlen_aligned;
 751         struct kvec bufferlist[3];
 752         u64 aligned_data = 0;
 753
 754         if (pagecount > MAX_PAGE_BUFFER_COUNT)
 755                 return -EINVAL;
 756
 757         /*
 758          * Adjust the size down since vmbus_channel_packet_page_buffer is the
 759          * largest size we support
 760          */
 761         descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
 762                           ((MAX_PAGE_BUFFER_COUNT - pagecount) *
 763                           sizeof(struct hv_page_buffer));
 764         packetlen = descsize + bufferlen;
 765         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 766
 767         /* Setup the descriptor */
 768         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
 769         desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 770         desc.dataoffset8 = descsize >> 3; /* in 8-bytes granularity */
 771         desc.length8 = (u16)(packetlen_aligned >> 3);
 772         desc.transactionid = requestid;
 773         desc.reserved = 0;
 774         desc.rangecount = pagecount;
 775
 776         for (i = 0; i < pagecount; i++) {
 777                 desc.range[i].len = pagebuffers[i].len;
 778                 desc.range[i].offset = pagebuffers[i].offset;
 779                 desc.range[i].pfn        = pagebuffers[i].pfn;
 780         }
 781
 782         bufferlist[0].iov_base = &desc;
 783         bufferlist[0].iov_len = descsize;
 784         bufferlist[1].iov_base = buffer;
 785         bufferlist[1].iov_len = bufferlen;
 786         bufferlist[2].iov_base = &aligned_data;
 787         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 788
 789         return hv_ringbuffer_write(channel, bufferlist, 3);
 790 }
 791 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
 792
 793 /*
 794  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
 795  * using a GPADL Direct packet type.
 796  * The buffer includes the vmbus descriptor.
 797  */
 798 int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
 799                               struct vmbus_packet_mpb_array *desc,
 800                               u32 desc_size,
 801                               void *buffer, u32 bufferlen, u64 requestid)
 802 {
 803         u32 packetlen;
 804         u32 packetlen_aligned;
 805         struct kvec bufferlist[3];
 806         u64 aligned_data = 0;
 807
 808         packetlen = desc_size + bufferlen;
 809         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 810
 811         /* Setup the descriptor */
 812         desc->type = VM_PKT_DATA_USING_GPA_DIRECT;
 813         desc->flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 814         desc->dataoffset8 = desc_size >> 3; /* in 8-bytes granularity */
 815         desc->length8 = (u16)(packetlen_aligned >> 3);
 816         desc->transactionid = requestid;
 817         desc->reserved = 0;
 818         desc->rangecount = 1;
 819
 820         bufferlist[0].iov_base = desc;
 821         bufferlist[0].iov_len = desc_size;
 822         bufferlist[1].iov_base = buffer;
 823         bufferlist[1].iov_len = bufferlen;
 824         bufferlist[2].iov_base = &aligned_data;
 825         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 826
 827         return hv_ringbuffer_write(channel, bufferlist, 3);
 828 }
 829 EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc);
 830
 831 /**
 832  * vmbus_recvpacket() - Retrieve the user packet on the specified channel
 833  * @channel: Pointer to vmbus_channel structure.
 834  * @buffer: Pointer to the buffer you want to receive the data into.
 835  * @bufferlen: Maximum size of what the the buffer will hold
 836  * @buffer_actual_len: The actual size of the data after it was received
 837  * @requestid: Identifier of the request
 838  *
 839  * Receives directly from the hyper-v vmbus and puts the data it received
 840  * into Buffer. This will receive the data unparsed from hyper-v.
 841  *
 842  * Mainly used by Hyper-V drivers.
 843  */
 844 static inline int
 845 __vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
 846                    u32 bufferlen, u32 *buffer_actual_len, u64 *requestid,
 847                    bool raw)
 848 {
 849         return hv_ringbuffer_read(channel, buffer, bufferlen,
 850                                   buffer_actual_len, requestid, raw);
 851
 852 }
 853
 854 int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
 855                      u32 bufferlen, u32 *buffer_actual_len,
 856                      u64 *requestid)
 857 {
 858         return __vmbus_recvpacket(channel, buffer, bufferlen,
 859                                   buffer_actual_len, requestid, false);
 860 }
 861 EXPORT_SYMBOL(vmbus_recvpacket);
 862
 863 /*
 864  * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
 865  */
 866 int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
 867                               u32 bufferlen, u32 *buffer_actual_len,
 868                               u64 *requestid)
 869 {
 870         return __vmbus_recvpacket(channel, buffer, bufferlen,
 871                                   buffer_actual_len, requestid, true);
 872 }
 873 EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);