drivers/scsi/storvsc_drv.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  *   K. Y. Srinivasan <kys@microsoft.com>
  21  */
  22
  23 #include <linux/kernel.h>
  24 #include <linux/wait.h>
  25 #include <linux/sched.h>
  26 #include <linux/completion.h>
  27 #include <linux/string.h>
  28 #include <linux/mm.h>
  29 #include <linux/delay.h>
  30 #include <linux/init.h>
  31 #include <linux/slab.h>
  32 #include <linux/module.h>
  33 #include <linux/device.h>
  34 #include <linux/hyperv.h>
  35 #include <linux/blkdev.h>
  36 #include <scsi/scsi.h>
  37 #include <scsi/scsi_cmnd.h>
  38 #include <scsi/scsi_host.h>
  39 #include <scsi/scsi_device.h>
  40 #include <scsi/scsi_tcq.h>
  41 #include <scsi/scsi_eh.h>
  42 #include <scsi/scsi_devinfo.h>
  43 #include <scsi/scsi_dbg.h>
  44
  45 /*
  46  * All wire protocol details (storage protocol between the guest and the host)
  47  * are consolidated here.
  48  *
  49  * Begin protocol definitions.
  50  */
  51
  52 /*
  53  * Version history:
  54  * V1 Beta: 0.1
  55  * V1 RC < 2008/1/31: 1.0
  56  * V1 RC > 2008/1/31:  2.0
  57  * Win7: 4.2
  58  * Win8: 5.1
  59  * Win8.1: 6.0
  60  * Win10: 6.2
  61  */
  62
  63 #define VMSTOR_PROTO_VERSION(MAJOR_, MINOR_)    ((((MAJOR_) & 0xff) << 8) | \
  64                                                 (((MINOR_) & 0xff)))
  65
  66 #define VMSTOR_PROTO_VERSION_WIN6       VMSTOR_PROTO_VERSION(2, 0)
  67 #define VMSTOR_PROTO_VERSION_WIN7       VMSTOR_PROTO_VERSION(4, 2)
  68 #define VMSTOR_PROTO_VERSION_WIN8       VMSTOR_PROTO_VERSION(5, 1)
  69 #define VMSTOR_PROTO_VERSION_WIN8_1     VMSTOR_PROTO_VERSION(6, 0)
  70 #define VMSTOR_PROTO_VERSION_WIN10      VMSTOR_PROTO_VERSION(6, 2)
  71
  72 /*  Packet structure describing virtual storage requests. */
  73 enum vstor_packet_operation {
  74         VSTOR_OPERATION_COMPLETE_IO             = 1,
  75         VSTOR_OPERATION_REMOVE_DEVICE           = 2,
  76         VSTOR_OPERATION_EXECUTE_SRB             = 3,
  77         VSTOR_OPERATION_RESET_LUN               = 4,
  78         VSTOR_OPERATION_RESET_ADAPTER           = 5,
  79         VSTOR_OPERATION_RESET_BUS               = 6,
  80         VSTOR_OPERATION_BEGIN_INITIALIZATION    = 7,
  81         VSTOR_OPERATION_END_INITIALIZATION      = 8,
  82         VSTOR_OPERATION_QUERY_PROTOCOL_VERSION  = 9,
  83         VSTOR_OPERATION_QUERY_PROPERTIES        = 10,
  84         VSTOR_OPERATION_ENUMERATE_BUS           = 11,
  85         VSTOR_OPERATION_FCHBA_DATA              = 12,
  86         VSTOR_OPERATION_CREATE_SUB_CHANNELS     = 13,
  87         VSTOR_OPERATION_MAXIMUM                 = 13
  88 };
  89
  90 /*
  91  * WWN packet for Fibre Channel HBA
  92  */
  93
  94 struct hv_fc_wwn_packet {
  95         bool    primary_active;
  96         u8      reserved1;
  97         u8      reserved2;
  98         u8      primary_port_wwn[8];
  99         u8      primary_node_wwn[8];
 100         u8      secondary_port_wwn[8];
 101         u8      secondary_node_wwn[8];
 102 };
 103
 104
 105
 106 /*
 107  * SRB Flag Bits
 108  */
 109
 110 #define SRB_FLAGS_QUEUE_ACTION_ENABLE           0x00000002
 111 #define SRB_FLAGS_DISABLE_DISCONNECT            0x00000004
 112 #define SRB_FLAGS_DISABLE_SYNCH_TRANSFER        0x00000008
 113 #define SRB_FLAGS_BYPASS_FROZEN_QUEUE           0x00000010
 114 #define SRB_FLAGS_DISABLE_AUTOSENSE             0x00000020
 115 #define SRB_FLAGS_DATA_IN                       0x00000040
 116 #define SRB_FLAGS_DATA_OUT                      0x00000080
 117 #define SRB_FLAGS_NO_DATA_TRANSFER              0x00000000
 118 #define SRB_FLAGS_UNSPECIFIED_DIRECTION (SRB_FLAGS_DATA_IN | SRB_FLAGS_DATA_OUT)
 119 #define SRB_FLAGS_NO_QUEUE_FREEZE               0x00000100
 120 #define SRB_FLAGS_ADAPTER_CACHE_ENABLE          0x00000200
 121 #define SRB_FLAGS_FREE_SENSE_BUFFER             0x00000400
 122
 123 /*
 124  * This flag indicates the request is part of the workflow for processing a D3.
 125  */
 126 #define SRB_FLAGS_D3_PROCESSING                 0x00000800
 127 #define SRB_FLAGS_IS_ACTIVE                     0x00010000
 128 #define SRB_FLAGS_ALLOCATED_FROM_ZONE           0x00020000
 129 #define SRB_FLAGS_SGLIST_FROM_POOL              0x00040000
 130 #define SRB_FLAGS_BYPASS_LOCKED_QUEUE           0x00080000
 131 #define SRB_FLAGS_NO_KEEP_AWAKE                 0x00100000
 132 #define SRB_FLAGS_PORT_DRIVER_ALLOCSENSE        0x00200000
 133 #define SRB_FLAGS_PORT_DRIVER_SENSEHASPORT      0x00400000
 134 #define SRB_FLAGS_DONT_START_NEXT_PACKET        0x00800000
 135 #define SRB_FLAGS_PORT_DRIVER_RESERVED          0x0F000000
 136 #define SRB_FLAGS_CLASS_DRIVER_RESERVED         0xF0000000
 137
 138
 139 /*
 140  * Platform neutral description of a scsi request -
 141  * this remains the same across the write regardless of 32/64 bit
 142  * note: it's patterned off the SCSI_PASS_THROUGH structure
 143  */
 144 #define STORVSC_MAX_CMD_LEN                     0x10
 145
 146 #define POST_WIN7_STORVSC_SENSE_BUFFER_SIZE     0x14
 147 #define PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE      0x12
 148
 149 #define STORVSC_SENSE_BUFFER_SIZE               0x14
 150 #define STORVSC_MAX_BUF_LEN_WITH_PADDING        0x14
 151
 152 /*
 153  * Sense buffer size changed in win8; have a run-time
 154  * variable to track the size we should use.  This value will
 155  * likely change during protocol negotiation but it is valid
 156  * to start by assuming pre-Win8.
 157  */
 158 static int sense_buffer_size = PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE;
 159
 160 /*
 161  * The storage protocol version is determined during the
 162  * initial exchange with the host.  It will indicate which
 163  * storage functionality is available in the host.
 164 */
 165 static int vmstor_proto_version;
 166
 167 struct vmscsi_win8_extension {
 168         /*
 169          * The following were added in Windows 8
 170          */
 171         u16 reserve;
 172         u8  queue_tag;
 173         u8  queue_action;
 174         u32 srb_flags;
 175         u32 time_out_value;
 176         u32 queue_sort_ey;
 177 } __packed;
 178
 179 struct vmscsi_request {
 180         u16 length;
 181         u8 srb_status;
 182         u8 scsi_status;
 183
 184         u8  port_number;
 185         u8  path_id;
 186         u8  target_id;
 187         u8  lun;
 188
 189         u8  cdb_length;
 190         u8  sense_info_length;
 191         u8  data_in;
 192         u8  reserved;
 193
 194         u32 data_transfer_length;
 195
 196         union {
 197                 u8 cdb[STORVSC_MAX_CMD_LEN];
 198                 u8 sense_data[STORVSC_SENSE_BUFFER_SIZE];
 199                 u8 reserved_array[STORVSC_MAX_BUF_LEN_WITH_PADDING];
 200         };
 201         /*
 202          * The following was added in win8.
 203          */
 204         struct vmscsi_win8_extension win8_extension;
 205
 206 } __attribute((packed));
 207
 208
 209 /*
 210  * The size of the vmscsi_request has changed in win8. The
 211  * additional size is because of new elements added to the
 212  * structure. These elements are valid only when we are talking
 213  * to a win8 host.
 214  * Track the correction to size we need to apply. This value
 215  * will likely change during protocol negotiation but it is
 216  * valid to start by assuming pre-Win8.
 217  */
 218 static int vmscsi_size_delta = sizeof(struct vmscsi_win8_extension);
 219
 220 /*
 221  * The list of storage protocols in order of preference.
 222  */
 223 struct vmstor_protocol {
 224         int protocol_version;
 225         int sense_buffer_size;
 226         int vmscsi_size_delta;
 227 };
 228
 229
 230 static const struct vmstor_protocol vmstor_protocols[] = {
 231         {
 232                 VMSTOR_PROTO_VERSION_WIN10,
 233                 POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
 234                 0
 235         },
 236         {
 237                 VMSTOR_PROTO_VERSION_WIN8_1,
 238                 POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
 239                 0
 240         },
 241         {
 242                 VMSTOR_PROTO_VERSION_WIN8,
 243                 POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
 244                 0
 245         },
 246         {
 247                 VMSTOR_PROTO_VERSION_WIN7,
 248                 PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
 249                 sizeof(struct vmscsi_win8_extension),
 250         },
 251         {
 252                 VMSTOR_PROTO_VERSION_WIN6,
 253                 PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
 254                 sizeof(struct vmscsi_win8_extension),
 255         }
 256 };
 257
 258
 259 /*
 260  * This structure is sent during the intialization phase to get the different
 261  * properties of the channel.
 262  */
 263
 264 #define STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL          0x1
 265
 266 struct vmstorage_channel_properties {
 267         u32 reserved;
 268         u16 max_channel_cnt;
 269         u16 reserved1;
 270
 271         u32 flags;
 272         u32   max_transfer_bytes;
 273
 274         u64  reserved2;
 275 } __packed;
 276
 277 /*  This structure is sent during the storage protocol negotiations. */
 278 struct vmstorage_protocol_version {
 279         /* Major (MSW) and minor (LSW) version numbers. */
 280         u16 major_minor;
 281
 282         /*
 283          * Revision number is auto-incremented whenever this file is changed
 284          * (See FILL_VMSTOR_REVISION macro above).  Mismatch does not
 285          * definitely indicate incompatibility--but it does indicate mismatched
 286          * builds.
 287          * This is only used on the windows side. Just set it to 0.
 288          */
 289         u16 revision;
 290 } __packed;
 291
 292 /* Channel Property Flags */
 293 #define STORAGE_CHANNEL_REMOVABLE_FLAG          0x1
 294 #define STORAGE_CHANNEL_EMULATED_IDE_FLAG       0x2
 295
 296 struct vstor_packet {
 297         /* Requested operation type */
 298         enum vstor_packet_operation operation;
 299
 300         /*  Flags - see below for values */
 301         u32 flags;
 302
 303         /* Status of the request returned from the server side. */
 304         u32 status;
 305
 306         /* Data payload area */
 307         union {
 308                 /*
 309                  * Structure used to forward SCSI commands from the
 310                  * client to the server.
 311                  */
 312                 struct vmscsi_request vm_srb;
 313
 314                 /* Structure used to query channel properties. */
 315                 struct vmstorage_channel_properties storage_channel_properties;
 316
 317                 /* Used during version negotiations. */
 318                 struct vmstorage_protocol_version version;
 319
 320                 /* Fibre channel address packet */
 321                 struct hv_fc_wwn_packet wwn_packet;
 322
 323                 /* Number of sub-channels to create */
 324                 u16 sub_channel_count;
 325
 326                 /* This will be the maximum of the union members */
 327                 u8  buffer[0x34];
 328         };
 329 } __packed;
 330
 331 /*
 332  * Packet Flags:
 333  *
 334  * This flag indicates that the server should send back a completion for this
 335  * packet.
 336  */
 337
 338 #define REQUEST_COMPLETION_FLAG 0x1
 339
 340 /* Matches Windows-end */
 341 enum storvsc_request_type {
 342         WRITE_TYPE = 0,
 343         READ_TYPE,
 344         UNKNOWN_TYPE,
 345 };
 346
 347 /*
 348  * SRB status codes and masks; a subset of the codes used here.
 349  */
 350
 351 #define SRB_STATUS_AUTOSENSE_VALID      0x80
 352 #define SRB_STATUS_INVALID_LUN  0x20
 353 #define SRB_STATUS_SUCCESS      0x01
 354 #define SRB_STATUS_ABORTED      0x02
 355 #define SRB_STATUS_ERROR        0x04
 356
 357 /*
 358  * This is the end of Protocol specific defines.
 359  */
 360
 361 static int storvsc_ringbuffer_size = (256 * PAGE_SIZE);
 362 static u32 max_outstanding_req_per_channel;
 363
 364 static int storvsc_vcpus_per_sub_channel = 4;
 365
 366 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
 367 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
 368
 369 module_param(storvsc_vcpus_per_sub_channel, int, S_IRUGO);
 370 MODULE_PARM_DESC(vcpus_per_sub_channel, "Ratio of VCPUs to subchannels");
 371 /*
 372  * Timeout in seconds for all devices managed by this driver.
 373  */
 374 static int storvsc_timeout = 180;
 375
 376 static int msft_blist_flags = BLIST_TRY_VPD_PAGES;
 377
 378
 379 static void storvsc_on_channel_callback(void *context);
 380
 381 #define STORVSC_MAX_LUNS_PER_TARGET                     255
 382 #define STORVSC_MAX_TARGETS                             2
 383 #define STORVSC_MAX_CHANNELS                            8
 384
 385 #define STORVSC_FC_MAX_LUNS_PER_TARGET                  255
 386 #define STORVSC_FC_MAX_TARGETS                          128
 387 #define STORVSC_FC_MAX_CHANNELS                         8
 388
 389 #define STORVSC_IDE_MAX_LUNS_PER_TARGET                 64
 390 #define STORVSC_IDE_MAX_TARGETS                         1
 391 #define STORVSC_IDE_MAX_CHANNELS                        1
 392
 393 struct storvsc_cmd_request {
 394         struct scsi_cmnd *cmd;
 395
 396         unsigned int bounce_sgl_count;
 397         struct scatterlist *bounce_sgl;
 398
 399         struct hv_device *device;
 400
 401         /* Synchronize the request/response if needed */
 402         struct completion wait_event;
 403
 404         struct vmbus_channel_packet_multipage_buffer mpb;
 405         struct vmbus_packet_mpb_array *payload;
 406         u32 payload_sz;
 407
 408         struct vstor_packet vstor_packet;
 409 };
 410
 411
 412 /* A storvsc device is a device object that contains a vmbus channel */
 413 struct storvsc_device {
 414         struct hv_device *device;
 415
 416         bool     destroy;
 417         bool     drain_notify;
 418         bool     open_sub_channel;
 419         atomic_t num_outstanding_req;
 420         struct Scsi_Host *host;
 421
 422         wait_queue_head_t waiting_to_drain;
 423
 424         /*
 425          * Each unique Port/Path/Target represents 1 channel ie scsi
 426          * controller. In reality, the pathid, targetid is always 0
 427          * and the port is set by us
 428          */
 429         unsigned int port_number;
 430         unsigned char path_id;
 431         unsigned char target_id;
 432
 433         /*
 434          * Max I/O, the device can support.
 435          */
 436         u32   max_transfer_bytes;
 437         /* Used for vsc/vsp channel reset process */
 438         struct storvsc_cmd_request init_request;
 439         struct storvsc_cmd_request reset_request;
 440 };
 441
 442 struct hv_host_device {
 443         struct hv_device *dev;
 444         unsigned int port;
 445         unsigned char path;
 446         unsigned char target;
 447 };
 448
 449 struct storvsc_scan_work {
 450         struct work_struct work;
 451         struct Scsi_Host *host;
 452         uint lun;
 453 };
 454
 455 static void storvsc_device_scan(struct work_struct *work)
 456 {
 457         struct storvsc_scan_work *wrk;
 458         uint lun;
 459         struct scsi_device *sdev;
 460
 461         wrk = container_of(work, struct storvsc_scan_work, work);
 462         lun = wrk->lun;
 463
 464         sdev = scsi_device_lookup(wrk->host, 0, 0, lun);
 465         if (!sdev)
 466                 goto done;
 467         scsi_rescan_device(&sdev->sdev_gendev);
 468         scsi_device_put(sdev);
 469
 470 done:
 471         kfree(wrk);
 472 }
 473
 474 static void storvsc_host_scan(struct work_struct *work)
 475 {
 476         struct storvsc_scan_work *wrk;
 477         struct Scsi_Host *host;
 478         struct scsi_device *sdev;
 479
 480         wrk = container_of(work, struct storvsc_scan_work, work);
 481         host = wrk->host;
 482
 483         /*
 484          * Before scanning the host, first check to see if any of the
 485          * currrently known devices have been hot removed. We issue a
 486          * "unit ready" command against all currently known devices.
 487          * This I/O will result in an error for devices that have been
 488          * removed. As part of handling the I/O error, we remove the device.
 489          *
 490          * When a LUN is added or removed, the host sends us a signal to
 491          * scan the host. Thus we are forced to discover the LUNs that
 492          * may have been removed this way.
 493          */
 494         mutex_lock(&host->scan_mutex);
 495         shost_for_each_device(sdev, host)
 496                 scsi_test_unit_ready(sdev, 1, 1, NULL);
 497         mutex_unlock(&host->scan_mutex);
 498         /*
 499          * Now scan the host to discover LUNs that may have been added.
 500          */
 501         scsi_scan_host(host);
 502
 503         kfree(wrk);
 504 }
 505
 506 static void storvsc_remove_lun(struct work_struct *work)
 507 {
 508         struct storvsc_scan_work *wrk;
 509         struct scsi_device *sdev;
 510
 511         wrk = container_of(work, struct storvsc_scan_work, work);
 512         if (!scsi_host_get(wrk->host))
 513                 goto done;
 514
 515         sdev = scsi_device_lookup(wrk->host, 0, 0, wrk->lun);
 516
 517         if (sdev) {
 518                 scsi_remove_device(sdev);
 519                 scsi_device_put(sdev);
 520         }
 521         scsi_host_put(wrk->host);
 522
 523 done:
 524         kfree(wrk);
 525 }
 526
 527
 528 /*
 529  * We can get incoming messages from the host that are not in response to
 530  * messages that we have sent out. An example of this would be messages
 531  * received by the guest to notify dynamic addition/removal of LUNs. To
 532  * deal with potential race conditions where the driver may be in the
 533  * midst of being unloaded when we might receive an unsolicited message
 534  * from the host, we have implemented a mechanism to gurantee sequential
 535  * consistency:
 536  *
 537  * 1) Once the device is marked as being destroyed, we will fail all
 538  *    outgoing messages.
 539  * 2) We permit incoming messages when the device is being destroyed,
 540  *    only to properly account for messages already sent out.
 541  */
 542
 543 static inline struct storvsc_device *get_out_stor_device(
 544                                         struct hv_device *device)
 545 {
 546         struct storvsc_device *stor_device;
 547
 548         stor_device = hv_get_drvdata(device);
 549
 550         if (stor_device && stor_device->destroy)
 551                 stor_device = NULL;
 552
 553         return stor_device;
 554 }
 555
 556
 557 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
 558 {
 559         dev->drain_notify = true;
 560         wait_event(dev->waiting_to_drain,
 561                    atomic_read(&dev->num_outstanding_req) == 0);
 562         dev->drain_notify = false;
 563 }
 564
 565 static inline struct storvsc_device *get_in_stor_device(
 566                                         struct hv_device *device)
 567 {
 568         struct storvsc_device *stor_device;
 569
 570         stor_device = hv_get_drvdata(device);
 571
 572         if (!stor_device)
 573                 goto get_in_err;
 574
 575         /*
 576          * If the device is being destroyed; allow incoming
 577          * traffic only to cleanup outstanding requests.
 578          */
 579
 580         if (stor_device->destroy  &&
 581                 (atomic_read(&stor_device->num_outstanding_req) == 0))
 582                 stor_device = NULL;
 583
 584 get_in_err:
 585         return stor_device;
 586
 587 }
 588
 589 static void destroy_bounce_buffer(struct scatterlist *sgl,
 590                                   unsigned int sg_count)
 591 {
 592         int i;
 593         struct page *page_buf;
 594
 595         for (i = 0; i < sg_count; i++) {
 596                 page_buf = sg_page((&sgl[i]));
 597                 if (page_buf != NULL)
 598                         __free_page(page_buf);
 599         }
 600
 601         kfree(sgl);
 602 }
 603
 604 static int do_bounce_buffer(struct scatterlist *sgl, unsigned int sg_count)
 605 {
 606         int i;
 607
 608         /* No need to check */
 609         if (sg_count < 2)
 610                 return -1;
 611
 612         /* We have at least 2 sg entries */
 613         for (i = 0; i < sg_count; i++) {
 614                 if (i == 0) {
 615                         /* make sure 1st one does not have hole */
 616                         if (sgl[i].offset + sgl[i].length != PAGE_SIZE)
 617                                 return i;
 618                 } else if (i == sg_count - 1) {
 619                         /* make sure last one does not have hole */
 620                         if (sgl[i].offset != 0)
 621                                 return i;
 622                 } else {
 623                         /* make sure no hole in the middle */
 624                         if (sgl[i].length != PAGE_SIZE || sgl[i].offset != 0)
 625                                 return i;
 626                 }
 627         }
 628         return -1;
 629 }
 630
 631 static struct scatterlist *create_bounce_buffer(struct scatterlist *sgl,
 632                                                 unsigned int sg_count,
 633                                                 unsigned int len,
 634                                                 int write)
 635 {
 636         int i;
 637         int num_pages;
 638         struct scatterlist *bounce_sgl;
 639         struct page *page_buf;
 640         unsigned int buf_len = ((write == WRITE_TYPE) ? 0 : PAGE_SIZE);
 641
 642         num_pages = ALIGN(len, PAGE_SIZE) >> PAGE_SHIFT;
 643
 644         bounce_sgl = kcalloc(num_pages, sizeof(struct scatterlist), GFP_ATOMIC);
 645         if (!bounce_sgl)
 646                 return NULL;
 647
 648         sg_init_table(bounce_sgl, num_pages);
 649         for (i = 0; i < num_pages; i++) {
 650                 page_buf = alloc_page(GFP_ATOMIC);
 651                 if (!page_buf)
 652                         goto cleanup;
 653                 sg_set_page(&bounce_sgl[i], page_buf, buf_len, 0);
 654         }
 655
 656         return bounce_sgl;
 657
 658 cleanup:
 659         destroy_bounce_buffer(bounce_sgl, num_pages);
 660         return NULL;
 661 }
 662
 663 /* Assume the original sgl has enough room */
 664 static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl,
 665                                             struct scatterlist *bounce_sgl,
 666                                             unsigned int orig_sgl_count,
 667                                             unsigned int bounce_sgl_count)
 668 {
 669         int i;
 670         int j = 0;
 671         unsigned long src, dest;
 672         unsigned int srclen, destlen, copylen;
 673         unsigned int total_copied = 0;
 674         unsigned long bounce_addr = 0;
 675         unsigned long dest_addr = 0;
 676         unsigned long flags;
 677         struct scatterlist *cur_dest_sgl;
 678         struct scatterlist *cur_src_sgl;
 679
 680         local_irq_save(flags);
 681         cur_dest_sgl = orig_sgl;
 682         cur_src_sgl = bounce_sgl;
 683         for (i = 0; i < orig_sgl_count; i++) {
 684                 dest_addr = (unsigned long)
 685                                 kmap_atomic(sg_page(cur_dest_sgl)) +
 686                                 cur_dest_sgl->offset;
 687                 dest = dest_addr;
 688                 destlen = cur_dest_sgl->length;
 689
 690                 if (bounce_addr == 0)
 691                         bounce_addr = (unsigned long)kmap_atomic(
 692                                                         sg_page(cur_src_sgl));
 693
 694                 while (destlen) {
 695                         src = bounce_addr + cur_src_sgl->offset;
 696                         srclen = cur_src_sgl->length - cur_src_sgl->offset;
 697
 698                         copylen = min(srclen, destlen);
 699                         memcpy((void *)dest, (void *)src, copylen);
 700
 701                         total_copied += copylen;
 702                         cur_src_sgl->offset += copylen;
 703                         destlen -= copylen;
 704                         dest += copylen;
 705
 706                         if (cur_src_sgl->offset == cur_src_sgl->length) {
 707                                 /* full */
 708                                 kunmap_atomic((void *)bounce_addr);
 709                                 j++;
 710
 711                                 /*
 712                                  * It is possible that the number of elements
 713                                  * in the bounce buffer may not be equal to
 714                                  * the number of elements in the original
 715                                  * scatter list. Handle this correctly.
 716                                  */
 717
 718                                 if (j == bounce_sgl_count) {
 719                                         /*
 720                                          * We are done; cleanup and return.
 721                                          */
 722                                         kunmap_atomic((void *)(dest_addr -
 723                                                 cur_dest_sgl->offset));
 724                                         local_irq_restore(flags);
 725                                         return total_copied;
 726                                 }
 727
 728                                 /* if we need to use another bounce buffer */
 729                                 if (destlen || i != orig_sgl_count - 1) {
 730                                         cur_src_sgl = sg_next(cur_src_sgl);
 731                                         bounce_addr = (unsigned long)
 732                                                         kmap_atomic(
 733                                                         sg_page(cur_src_sgl));
 734                                 }
 735                         } else if (destlen == 0 && i == orig_sgl_count - 1) {
 736                                 /* unmap the last bounce that is < PAGE_SIZE */
 737                                 kunmap_atomic((void *)bounce_addr);
 738                         }
 739                 }
 740
 741                 kunmap_atomic((void *)(dest_addr - cur_dest_sgl->offset));
 742                 cur_dest_sgl = sg_next(cur_dest_sgl);
 743         }
 744
 745         local_irq_restore(flags);
 746
 747         return total_copied;
 748 }
 749
 750 /* Assume the bounce_sgl has enough room ie using the create_bounce_buffer() */
 751 static unsigned int copy_to_bounce_buffer(struct scatterlist *orig_sgl,
 752                                           struct scatterlist *bounce_sgl,
 753                                           unsigned int orig_sgl_count)
 754 {
 755         int i;
 756         int j = 0;
 757         unsigned long src, dest;
 758         unsigned int srclen, destlen, copylen;
 759         unsigned int total_copied = 0;
 760         unsigned long bounce_addr = 0;
 761         unsigned long src_addr = 0;
 762         unsigned long flags;
 763         struct scatterlist *cur_src_sgl;
 764         struct scatterlist *cur_dest_sgl;
 765
 766         local_irq_save(flags);
 767
 768         cur_src_sgl = orig_sgl;
 769         cur_dest_sgl = bounce_sgl;
 770
 771         for (i = 0; i < orig_sgl_count; i++) {
 772                 src_addr = (unsigned long)
 773                                 kmap_atomic(sg_page(cur_src_sgl)) +
 774                                 cur_src_sgl->offset;
 775                 src = src_addr;
 776                 srclen = cur_src_sgl->length;
 777
 778                 if (bounce_addr == 0)
 779                         bounce_addr = (unsigned long)
 780                                         kmap_atomic(sg_page(cur_dest_sgl));
 781
 782                 while (srclen) {
 783                         /* assume bounce offset always == 0 */
 784                         dest = bounce_addr + cur_dest_sgl->length;
 785                         destlen = PAGE_SIZE - cur_dest_sgl->length;
 786
 787                         copylen = min(srclen, destlen);
 788                         memcpy((void *)dest, (void *)src, copylen);
 789
 790                         total_copied += copylen;
 791                         cur_dest_sgl->length += copylen;
 792                         srclen -= copylen;
 793                         src += copylen;
 794
 795                         if (cur_dest_sgl->length == PAGE_SIZE) {
 796                                 /* full..move to next entry */
 797                                 kunmap_atomic((void *)bounce_addr);
 798                                 bounce_addr = 0;
 799                                 j++;
 800                         }
 801
 802                         /* if we need to use another bounce buffer */
 803                         if (srclen && bounce_addr == 0) {
 804                                 cur_dest_sgl = sg_next(cur_dest_sgl);
 805                                 bounce_addr = (unsigned long)
 806                                                 kmap_atomic(
 807                                                 sg_page(cur_dest_sgl));
 808                         }
 809
 810                 }
 811
 812                 kunmap_atomic((void *)(src_addr - cur_src_sgl->offset));
 813                 cur_src_sgl = sg_next(cur_src_sgl);
 814         }
 815
 816         if (bounce_addr)
 817                 kunmap_atomic((void *)bounce_addr);
 818
 819         local_irq_restore(flags);
 820
 821         return total_copied;
 822 }
 823
 824 static void handle_sc_creation(struct vmbus_channel *new_sc)
 825 {
 826         struct hv_device *device = new_sc->primary_channel->device_obj;
 827         struct storvsc_device *stor_device;
 828         struct vmstorage_channel_properties props;
 829
 830         stor_device = get_out_stor_device(device);
 831         if (!stor_device)
 832                 return;
 833
 834         if (stor_device->open_sub_channel == false)
 835                 return;
 836
 837         memset(&props, 0, sizeof(struct vmstorage_channel_properties));
 838
 839         vmbus_open(new_sc,
 840                    storvsc_ringbuffer_size,
 841                    storvsc_ringbuffer_size,
 842                    (void *)&props,
 843                    sizeof(struct vmstorage_channel_properties),
 844                    storvsc_on_channel_callback, new_sc);
 845 }
 846
 847 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
 848 {
 849         struct storvsc_device *stor_device;
 850         int num_cpus = num_online_cpus();
 851         int num_sc;
 852         struct storvsc_cmd_request *request;
 853         struct vstor_packet *vstor_packet;
 854         int ret, t;
 855
 856         num_sc = ((max_chns > num_cpus) ? num_cpus : max_chns);
 857         stor_device = get_out_stor_device(device);
 858         if (!stor_device)
 859                 return;
 860
 861         request = &stor_device->init_request;
 862         vstor_packet = &request->vstor_packet;
 863
 864         stor_device->open_sub_channel = true;
 865         /*
 866          * Establish a handler for dealing with subchannels.
 867          */
 868         vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
 869
 870         /*
 871          * Check to see if sub-channels have already been created. This
 872          * can happen when this driver is re-loaded after unloading.
 873          */
 874
 875         if (vmbus_are_subchannels_present(device->channel))
 876                 return;
 877
 878         stor_device->open_sub_channel = false;
 879         /*
 880          * Request the host to create sub-channels.
 881          */
 882         memset(request, 0, sizeof(struct storvsc_cmd_request));
 883         init_completion(&request->wait_event);
 884         vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
 885         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 886         vstor_packet->sub_channel_count = num_sc;
 887
 888         ret = vmbus_sendpacket(device->channel, vstor_packet,
 889                                (sizeof(struct vstor_packet) -
 890                                vmscsi_size_delta),
 891                                (unsigned long)request,
 892                                VM_PKT_DATA_INBAND,
 893                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 894
 895         if (ret != 0)
 896                 return;
 897
 898         t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
 899         if (t == 0)
 900                 return;
 901
 902         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
 903             vstor_packet->status != 0)
 904                 return;
 905
 906         /*
 907          * Now that we created the sub-channels, invoke the check; this
 908          * may trigger the callback.
 909          */
 910         stor_device->open_sub_channel = true;
 911         vmbus_are_subchannels_present(device->channel);
 912 }
 913
 914 static int storvsc_channel_init(struct hv_device *device)
 915 {
 916         struct storvsc_device *stor_device;
 917         struct storvsc_cmd_request *request;
 918         struct vstor_packet *vstor_packet;
 919         int ret, t, i;
 920         int max_chns;
 921         bool process_sub_channels = false;
 922
 923         stor_device = get_out_stor_device(device);
 924         if (!stor_device)
 925                 return -ENODEV;
 926
 927         request = &stor_device->init_request;
 928         vstor_packet = &request->vstor_packet;
 929
 930         /*
 931          * Now, initiate the vsc/vsp initialization protocol on the open
 932          * channel
 933          */
 934         memset(request, 0, sizeof(struct storvsc_cmd_request));
 935         init_completion(&request->wait_event);
 936         vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
 937         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 938
 939         ret = vmbus_sendpacket(device->channel, vstor_packet,
 940                                (sizeof(struct vstor_packet) -
 941                                vmscsi_size_delta),
 942                                (unsigned long)request,
 943                                VM_PKT_DATA_INBAND,
 944                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 945         if (ret != 0)
 946                 goto cleanup;
 947
 948         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
 949         if (t == 0) {
 950                 ret = -ETIMEDOUT;
 951                 goto cleanup;
 952         }
 953
 954         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
 955             vstor_packet->status != 0) {
 956                 ret = -EINVAL;
 957                 goto cleanup;
 958         }
 959
 960
 961         for (i = 0; i < ARRAY_SIZE(vmstor_protocols); i++) {
 962                 /* reuse the packet for version range supported */
 963                 memset(vstor_packet, 0, sizeof(struct vstor_packet));
 964                 vstor_packet->operation =
 965                         VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
 966                 vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 967
 968                 vstor_packet->version.major_minor =
 969                         vmstor_protocols[i].protocol_version;
 970
 971                 /*
 972                  * The revision number is only used in Windows; set it to 0.
 973                  */
 974                 vstor_packet->version.revision = 0;
 975
 976                 ret = vmbus_sendpacket(device->channel, vstor_packet,
 977                                (sizeof(struct vstor_packet) -
 978                                 vmscsi_size_delta),
 979                                (unsigned long)request,
 980                                VM_PKT_DATA_INBAND,
 981                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 982                 if (ret != 0)
 983                         goto cleanup;
 984
 985                 t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
 986                 if (t == 0) {
 987                         ret = -ETIMEDOUT;
 988                         goto cleanup;
 989                 }
 990
 991                 if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO) {
 992                         ret = -EINVAL;
 993                         goto cleanup;
 994                 }
 995
 996                 if (vstor_packet->status == 0) {
 997                         vmstor_proto_version =
 998                                 vmstor_protocols[i].protocol_version;
 999
1000                         sense_buffer_size =
1001                                 vmstor_protocols[i].sense_buffer_size;
1002
1003                         vmscsi_size_delta =
1004                                 vmstor_protocols[i].vmscsi_size_delta;
1005
1006                         break;
1007                 }
1008         }
1009
1010         if (vstor_packet->status != 0) {
1011                 ret = -EINVAL;
1012                 goto cleanup;
1013         }
1014
1015
1016         memset(vstor_packet, 0, sizeof(struct vstor_packet));
1017         vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
1018         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1019
1020         ret = vmbus_sendpacket(device->channel, vstor_packet,
1021                                (sizeof(struct vstor_packet) -
1022                                 vmscsi_size_delta),
1023                                (unsigned long)request,
1024                                VM_PKT_DATA_INBAND,
1025                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1026
1027         if (ret != 0)
1028                 goto cleanup;
1029
1030         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1031         if (t == 0) {
1032                 ret = -ETIMEDOUT;
1033                 goto cleanup;
1034         }
1035
1036         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
1037             vstor_packet->status != 0) {
1038                 ret = -EINVAL;
1039                 goto cleanup;
1040         }
1041
1042         /*
1043          * Check to see if multi-channel support is there.
1044          * Hosts that implement protocol version of 5.1 and above
1045          * support multi-channel.
1046          */
1047         max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
1048         if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN8) {
1049                 if (vstor_packet->storage_channel_properties.flags &
1050                     STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
1051                         process_sub_channels = true;
1052         }
1053         stor_device->max_transfer_bytes =
1054                 vstor_packet->storage_channel_properties.max_transfer_bytes;
1055
1056         memset(vstor_packet, 0, sizeof(struct vstor_packet));
1057         vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
1058         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1059
1060         ret = vmbus_sendpacket(device->channel, vstor_packet,
1061                                (sizeof(struct vstor_packet) -
1062                                 vmscsi_size_delta),
1063                                (unsigned long)request,
1064                                VM_PKT_DATA_INBAND,
1065                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1066
1067         if (ret != 0)
1068                 goto cleanup;
1069
1070         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1071         if (t == 0) {
1072                 ret = -ETIMEDOUT;
1073                 goto cleanup;
1074         }
1075
1076         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
1077             vstor_packet->status != 0) {
1078                 ret = -EINVAL;
1079                 goto cleanup;
1080         }
1081
1082         if (process_sub_channels)
1083                 handle_multichannel_storage(device, max_chns);
1084
1085
1086 cleanup:
1087         return ret;
1088 }
1089
1090 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
1091                                 struct scsi_cmnd *scmnd,
1092                                 struct Scsi_Host *host,
1093                                 u8 asc, u8 ascq)
1094 {
1095         struct storvsc_scan_work *wrk;
1096         void (*process_err_fn)(struct work_struct *work);
1097         bool do_work = false;
1098
1099         switch (vm_srb->srb_status) {
1100         case SRB_STATUS_ERROR:
1101                 /*
1102                  * If there is an error; offline the device since all
1103                  * error recovery strategies would have already been
1104                  * deployed on the host side. However, if the command
1105                  * were a pass-through command deal with it appropriately.
1106                  */
1107                 switch (scmnd->cmnd[0]) {
1108                 case ATA_16:
1109                 case ATA_12:
1110                         set_host_byte(scmnd, DID_PASSTHROUGH);
1111                         break;
1112                 /*
1113                  * On Some Windows hosts TEST_UNIT_READY command can return
1114                  * SRB_STATUS_ERROR, let the upper level code deal with it
1115                  * based on the sense information.
1116                  */
1117                 case TEST_UNIT_READY:
1118                         break;
1119                 default:
1120                         set_host_byte(scmnd, DID_TARGET_FAILURE);
1121                 }
1122                 break;
1123         case SRB_STATUS_INVALID_LUN:
1124                 do_work = true;
1125                 process_err_fn = storvsc_remove_lun;
1126                 break;
1127         case (SRB_STATUS_ABORTED | SRB_STATUS_AUTOSENSE_VALID):
1128                 if ((asc == 0x2a) && (ascq == 0x9)) {
1129                         do_work = true;
1130                         process_err_fn = storvsc_device_scan;
1131                         /*
1132                          * Retry the I/O that trigerred this.
1133                          */
1134                         set_host_byte(scmnd, DID_REQUEUE);
1135                 }
1136                 break;
1137         }
1138
1139         if (!do_work)
1140                 return;
1141
1142         /*
1143          * We need to schedule work to process this error; schedule it.
1144          */
1145         wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1146         if (!wrk) {
1147                 set_host_byte(scmnd, DID_TARGET_FAILURE);
1148                 return;
1149         }
1150
1151         wrk->host = host;
1152         wrk->lun = vm_srb->lun;
1153         INIT_WORK(&wrk->work, process_err_fn);
1154         schedule_work(&wrk->work);
1155 }
1156
1157
1158 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request)
1159 {
1160         struct scsi_cmnd *scmnd = cmd_request->cmd;
1161         struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1162         struct scsi_sense_hdr sense_hdr;
1163         struct vmscsi_request *vm_srb;
1164         struct Scsi_Host *host;
1165         struct storvsc_device *stor_dev;
1166         struct hv_device *dev = host_dev->dev;
1167         u32 payload_sz = cmd_request->payload_sz;
1168         void *payload = cmd_request->payload;
1169
1170         stor_dev = get_in_stor_device(dev);
1171         host = stor_dev->host;
1172
1173         vm_srb = &cmd_request->vstor_packet.vm_srb;
1174         if (cmd_request->bounce_sgl_count) {
1175                 if (vm_srb->data_in == READ_TYPE)
1176                         copy_from_bounce_buffer(scsi_sglist(scmnd),
1177                                         cmd_request->bounce_sgl,
1178                                         scsi_sg_count(scmnd),
1179                                         cmd_request->bounce_sgl_count);
1180                 destroy_bounce_buffer(cmd_request->bounce_sgl,
1181                                         cmd_request->bounce_sgl_count);
1182         }
1183
1184         scmnd->result = vm_srb->scsi_status;
1185
1186         if (scmnd->result) {
1187                 if (scsi_normalize_sense(scmnd->sense_buffer,
1188                                 SCSI_SENSE_BUFFERSIZE, &sense_hdr))
1189                         scsi_print_sense_hdr(scmnd->device, "storvsc",
1190                                              &sense_hdr);
1191         }
1192
1193         if (vm_srb->srb_status != SRB_STATUS_SUCCESS)
1194                 storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
1195                                          sense_hdr.ascq);
1196
1197         scsi_set_resid(scmnd,
1198                 cmd_request->payload->range.len -
1199                 vm_srb->data_transfer_length);
1200
1201         scmnd->scsi_done(scmnd);
1202
1203         if (payload_sz >
1204                 sizeof(struct vmbus_channel_packet_multipage_buffer))
1205                 kfree(payload);
1206 }
1207
1208 static void storvsc_on_io_completion(struct hv_device *device,
1209                                   struct vstor_packet *vstor_packet,
1210                                   struct storvsc_cmd_request *request)
1211 {
1212         struct storvsc_device *stor_device;
1213         struct vstor_packet *stor_pkt;
1214
1215         stor_device = hv_get_drvdata(device);
1216         stor_pkt = &request->vstor_packet;
1217
1218         /*
1219          * The current SCSI handling on the host side does
1220          * not correctly handle:
1221          * INQUIRY command with page code parameter set to 0x80
1222          * MODE_SENSE command with cmd[2] == 0x1c
1223          *
1224          * Setup srb and scsi status so this won't be fatal.
1225          * We do this so we can distinguish truly fatal failues
1226          * (srb status == 0x4) and off-line the device in that case.
1227          */
1228
1229         if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1230            (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1231                 vstor_packet->vm_srb.scsi_status = 0;
1232                 vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1233         }
1234
1235
1236         /* Copy over the status...etc */
1237         stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1238         stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1239         stor_pkt->vm_srb.sense_info_length =
1240         vstor_packet->vm_srb.sense_info_length;
1241
1242
1243         if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
1244                 /* CHECK_CONDITION */
1245                 if (vstor_packet->vm_srb.srb_status &
1246                         SRB_STATUS_AUTOSENSE_VALID) {
1247                         /* autosense data available */
1248
1249                         memcpy(request->cmd->sense_buffer,
1250                                vstor_packet->vm_srb.sense_data,
1251                                vstor_packet->vm_srb.sense_info_length);
1252
1253                 }
1254         }
1255
1256         stor_pkt->vm_srb.data_transfer_length =
1257         vstor_packet->vm_srb.data_transfer_length;
1258
1259         storvsc_command_completion(request);
1260
1261         if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1262                 stor_device->drain_notify)
1263                 wake_up(&stor_device->waiting_to_drain);
1264
1265
1266 }
1267
1268 static void storvsc_on_receive(struct hv_device *device,
1269                              struct vstor_packet *vstor_packet,
1270                              struct storvsc_cmd_request *request)
1271 {
1272         struct storvsc_scan_work *work;
1273         struct storvsc_device *stor_device;
1274
1275         switch (vstor_packet->operation) {
1276         case VSTOR_OPERATION_COMPLETE_IO:
1277                 storvsc_on_io_completion(device, vstor_packet, request);
1278                 break;
1279
1280         case VSTOR_OPERATION_REMOVE_DEVICE:
1281         case VSTOR_OPERATION_ENUMERATE_BUS:
1282                 stor_device = get_in_stor_device(device);
1283                 work = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1284                 if (!work)
1285                         return;
1286
1287                 INIT_WORK(&work->work, storvsc_host_scan);
1288                 work->host = stor_device->host;
1289                 schedule_work(&work->work);
1290                 break;
1291
1292         default:
1293                 break;
1294         }
1295 }
1296
1297 static void storvsc_on_channel_callback(void *context)
1298 {
1299         struct vmbus_channel *channel = (struct vmbus_channel *)context;
1300         struct hv_device *device;
1301         struct storvsc_device *stor_device;
1302         u32 bytes_recvd;
1303         u64 request_id;
1304         unsigned char packet[ALIGN(sizeof(struct vstor_packet), 8)];
1305         struct storvsc_cmd_request *request;
1306         int ret;
1307
1308         if (channel->primary_channel != NULL)
1309                 device = channel->primary_channel->device_obj;
1310         else
1311                 device = channel->device_obj;
1312
1313         stor_device = get_in_stor_device(device);
1314         if (!stor_device)
1315                 return;
1316
1317         do {
1318                 ret = vmbus_recvpacket(channel, packet,
1319                                        ALIGN((sizeof(struct vstor_packet) -
1320                                              vmscsi_size_delta), 8),
1321                                        &bytes_recvd, &request_id);
1322                 if (ret == 0 && bytes_recvd > 0) {
1323
1324                         request = (struct storvsc_cmd_request *)
1325                                         (unsigned long)request_id;
1326
1327                         if ((request == &stor_device->init_request) ||
1328                             (request == &stor_device->reset_request)) {
1329
1330                                 memcpy(&request->vstor_packet, packet,
1331                                        (sizeof(struct vstor_packet) -
1332                                         vmscsi_size_delta));
1333                                 complete(&request->wait_event);
1334                         } else {
1335                                 storvsc_on_receive(device,
1336                                                 (struct vstor_packet *)packet,
1337                                                 request);
1338                         }
1339                 } else {
1340                         break;
1341                 }
1342         } while (1);
1343
1344         return;
1345 }
1346
1347 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size)
1348 {
1349         struct vmstorage_channel_properties props;
1350         int ret;
1351
1352         memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1353
1354         ret = vmbus_open(device->channel,
1355                          ring_size,
1356                          ring_size,
1357                          (void *)&props,
1358                          sizeof(struct vmstorage_channel_properties),
1359                          storvsc_on_channel_callback, device->channel);
1360
1361         if (ret != 0)
1362                 return ret;
1363
1364         ret = storvsc_channel_init(device);
1365
1366         return ret;
1367 }
1368
1369 static int storvsc_dev_remove(struct hv_device *device)
1370 {
1371         struct storvsc_device *stor_device;
1372         unsigned long flags;
1373
1374         stor_device = hv_get_drvdata(device);
1375
1376         spin_lock_irqsave(&device->channel->inbound_lock, flags);
1377         stor_device->destroy = true;
1378         spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
1379
1380         /*
1381          * At this point, all outbound traffic should be disable. We
1382          * only allow inbound traffic (responses) to proceed so that
1383          * outstanding requests can be completed.
1384          */
1385
1386         storvsc_wait_to_drain(stor_device);
1387
1388         /*
1389          * Since we have already drained, we don't need to busy wait
1390          * as was done in final_release_stor_device()
1391          * Note that we cannot set the ext pointer to NULL until
1392          * we have drained - to drain the outgoing packets, we need to
1393          * allow incoming packets.
1394          */
1395         spin_lock_irqsave(&device->channel->inbound_lock, flags);
1396         hv_set_drvdata(device, NULL);
1397         spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
1398
1399         /* Close the channel */
1400         vmbus_close(device->channel);
1401
1402         kfree(stor_device);
1403         return 0;
1404 }
1405
1406 static int storvsc_do_io(struct hv_device *device,
1407                          struct storvsc_cmd_request *request)
1408 {
1409         struct storvsc_device *stor_device;
1410         struct vstor_packet *vstor_packet;
1411         struct vmbus_channel *outgoing_channel;
1412         int ret = 0;
1413
1414         vstor_packet = &request->vstor_packet;
1415         stor_device = get_out_stor_device(device);
1416
1417         if (!stor_device)
1418                 return -ENODEV;
1419
1420
1421         request->device  = device;
1422         /*
1423          * Select an an appropriate channel to send the request out.
1424          */
1425
1426         outgoing_channel = vmbus_get_outgoing_channel(device->channel);
1427
1428
1429         vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1430
1431         vstor_packet->vm_srb.length = (sizeof(struct vmscsi_request) -
1432                                         vmscsi_size_delta);
1433
1434
1435         vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1436
1437
1438         vstor_packet->vm_srb.data_transfer_length =
1439         request->payload->range.len;
1440
1441         vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1442
1443         if (request->payload->range.len) {
1444
1445                 ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
1446                                 request->payload, request->payload_sz,
1447                                 vstor_packet,
1448                                 (sizeof(struct vstor_packet) -
1449                                 vmscsi_size_delta),
1450                                 (unsigned long)request);
1451         } else {
1452                 ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
1453                                (sizeof(struct vstor_packet) -
1454                                 vmscsi_size_delta),
1455                                (unsigned long)request,
1456                                VM_PKT_DATA_INBAND,
1457                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1458         }
1459
1460         if (ret != 0)
1461                 return ret;
1462
1463         atomic_inc(&stor_device->num_outstanding_req);
1464
1465         return ret;
1466 }
1467
1468 static int storvsc_device_configure(struct scsi_device *sdevice)
1469 {
1470
1471         blk_queue_max_segment_size(sdevice->request_queue, PAGE_SIZE);
1472
1473         blk_queue_bounce_limit(sdevice->request_queue, BLK_BOUNCE_ANY);
1474
1475         blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1476
1477         sdevice->no_write_same = 1;
1478
1479         /*
1480          * Add blist flags to permit the reading of the VPD pages even when
1481          * the target may claim SPC-2 compliance. MSFT targets currently
1482          * claim SPC-2 compliance while they implement post SPC-2 features.
1483          * With this patch we can correctly handle WRITE_SAME_16 issues.
1484          */
1485         sdevice->sdev_bflags |= msft_blist_flags;
1486
1487         /*
1488          * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
1489          * if the device is a MSFT virtual device.  If the host is
1490          * WIN10 or newer, allow write_same.
1491          */
1492         if (!strncmp(sdevice->vendor, "Msft", 4)) {
1493                 switch (vmstor_proto_version) {
1494                 case VMSTOR_PROTO_VERSION_WIN8:
1495                 case VMSTOR_PROTO_VERSION_WIN8_1:
1496                         sdevice->scsi_level = SCSI_SPC_3;
1497                         break;
1498                 }
1499
1500                 if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN10)
1501                         sdevice->no_write_same = 0;
1502         }
1503
1504         return 0;
1505 }
1506
1507 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1508                            sector_t capacity, int *info)
1509 {
1510         sector_t nsect = capacity;
1511         sector_t cylinders = nsect;
1512         int heads, sectors_pt;
1513
1514         /*
1515          * We are making up these values; let us keep it simple.
1516          */
1517         heads = 0xff;
1518         sectors_pt = 0x3f;      /* Sectors per track */
1519         sector_div(cylinders, heads * sectors_pt);
1520         if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1521                 cylinders = 0xffff;
1522
1523         info[0] = heads;
1524         info[1] = sectors_pt;
1525         info[2] = (int)cylinders;
1526
1527         return 0;
1528 }
1529
1530 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1531 {
1532         struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1533         struct hv_device *device = host_dev->dev;
1534
1535         struct storvsc_device *stor_device;
1536         struct storvsc_cmd_request *request;
1537         struct vstor_packet *vstor_packet;
1538         int ret, t;
1539
1540
1541         stor_device = get_out_stor_device(device);
1542         if (!stor_device)
1543                 return FAILED;
1544
1545         request = &stor_device->reset_request;
1546         vstor_packet = &request->vstor_packet;
1547
1548         init_completion(&request->wait_event);
1549
1550         vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1551         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1552         vstor_packet->vm_srb.path_id = stor_device->path_id;
1553
1554         ret = vmbus_sendpacket(device->channel, vstor_packet,
1555                                (sizeof(struct vstor_packet) -
1556                                 vmscsi_size_delta),
1557                                (unsigned long)&stor_device->reset_request,
1558                                VM_PKT_DATA_INBAND,
1559                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1560         if (ret != 0)
1561                 return FAILED;
1562
1563         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1564         if (t == 0)
1565                 return TIMEOUT_ERROR;
1566
1567
1568         /*
1569          * At this point, all outstanding requests in the adapter
1570          * should have been flushed out and return to us
1571          * There is a potential race here where the host may be in
1572          * the process of responding when we return from here.
1573          * Just wait for all in-transit packets to be accounted for
1574          * before we return from here.
1575          */
1576         storvsc_wait_to_drain(stor_device);
1577
1578         return SUCCESS;
1579 }
1580
1581 /*
1582  * The host guarantees to respond to each command, although I/O latencies might
1583  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1584  * chance to perform EH.
1585  */
1586 static enum blk_eh_timer_return storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1587 {
1588         return BLK_EH_RESET_TIMER;
1589 }
1590
1591 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1592 {
1593         bool allowed = true;
1594         u8 scsi_op = scmnd->cmnd[0];
1595
1596         switch (scsi_op) {
1597         /* the host does not handle WRITE_SAME, log accident usage */
1598         case WRITE_SAME:
1599         /*
1600          * smartd sends this command and the host does not handle
1601          * this. So, don't send it.
1602          */
1603         case SET_WINDOW:
1604                 scmnd->result = ILLEGAL_REQUEST << 16;
1605                 allowed = false;
1606                 break;
1607         default:
1608                 break;
1609         }
1610         return allowed;
1611 }
1612
1613 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1614 {
1615         int ret;
1616         struct hv_host_device *host_dev = shost_priv(host);
1617         struct hv_device *dev = host_dev->dev;
1618         struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
1619         int i;
1620         struct scatterlist *sgl;
1621         unsigned int sg_count = 0;
1622         struct vmscsi_request *vm_srb;
1623         struct scatterlist *cur_sgl;
1624         struct vmbus_packet_mpb_array  *payload;
1625         u32 payload_sz;
1626         u32 length;
1627
1628         if (vmstor_proto_version <= VMSTOR_PROTO_VERSION_WIN8) {
1629                 /*
1630                  * On legacy hosts filter unimplemented commands.
1631                  * Future hosts are expected to correctly handle
1632                  * unsupported commands. Furthermore, it is
1633                  * possible that some of the currently
1634                  * unsupported commands maybe supported in
1635                  * future versions of the host.
1636                  */
1637                 if (!storvsc_scsi_cmd_ok(scmnd)) {
1638                         scmnd->scsi_done(scmnd);
1639                         return 0;
1640                 }
1641         }
1642
1643         /* Setup the cmd request */
1644         cmd_request->cmd = scmnd;
1645
1646         vm_srb = &cmd_request->vstor_packet.vm_srb;
1647         vm_srb->win8_extension.time_out_value = 60;
1648
1649         vm_srb->win8_extension.srb_flags |=
1650                 (SRB_FLAGS_QUEUE_ACTION_ENABLE |
1651                 SRB_FLAGS_DISABLE_SYNCH_TRANSFER);
1652
1653         /* Build the SRB */
1654         switch (scmnd->sc_data_direction) {
1655         case DMA_TO_DEVICE:
1656                 vm_srb->data_in = WRITE_TYPE;
1657                 vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_OUT;
1658                 break;
1659         case DMA_FROM_DEVICE:
1660                 vm_srb->data_in = READ_TYPE;
1661                 vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_IN;
1662                 break;
1663         case DMA_NONE:
1664                 vm_srb->data_in = UNKNOWN_TYPE;
1665                 vm_srb->win8_extension.srb_flags |= SRB_FLAGS_NO_DATA_TRANSFER;
1666                 break;
1667         default:
1668                 /*
1669                  * This is DMA_BIDIRECTIONAL or something else we are never
1670                  * supposed to see here.
1671                  */
1672                 WARN(1, "Unexpected data direction: %d\n",
1673                      scmnd->sc_data_direction);
1674                 return -EINVAL;
1675         }
1676
1677
1678         vm_srb->port_number = host_dev->port;
1679         vm_srb->path_id = scmnd->device->channel;
1680         vm_srb->target_id = scmnd->device->id;
1681         vm_srb->lun = scmnd->device->lun;
1682
1683         vm_srb->cdb_length = scmnd->cmd_len;
1684
1685         memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1686
1687         sgl = (struct scatterlist *)scsi_sglist(scmnd);
1688         sg_count = scsi_sg_count(scmnd);
1689
1690         length = scsi_bufflen(scmnd);
1691         payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
1692         payload_sz = sizeof(cmd_request->mpb);
1693
1694         if (sg_count) {
1695                 /* check if we need to bounce the sgl */
1696                 if (do_bounce_buffer(sgl, scsi_sg_count(scmnd)) != -1) {
1697                         cmd_request->bounce_sgl =
1698                                 create_bounce_buffer(sgl, sg_count,
1699                                                      length,
1700                                                      vm_srb->data_in);
1701                         if (!cmd_request->bounce_sgl)
1702                                 return SCSI_MLQUEUE_HOST_BUSY;
1703
1704                         cmd_request->bounce_sgl_count =
1705                                 ALIGN(length, PAGE_SIZE) >> PAGE_SHIFT;
1706
1707                         if (vm_srb->data_in == WRITE_TYPE)
1708                                 copy_to_bounce_buffer(sgl,
1709                                         cmd_request->bounce_sgl, sg_count);
1710
1711                         sgl = cmd_request->bounce_sgl;
1712                         sg_count = cmd_request->bounce_sgl_count;
1713                 }
1714
1715
1716                 if (sg_count > MAX_PAGE_BUFFER_COUNT) {
1717
1718                         payload_sz = (sg_count * sizeof(void *) +
1719                                       sizeof(struct vmbus_packet_mpb_array));
1720                         payload = kmalloc(payload_sz, GFP_ATOMIC);
1721                         if (!payload) {
1722                                 if (cmd_request->bounce_sgl_count)
1723                                         destroy_bounce_buffer(
1724                                         cmd_request->bounce_sgl,
1725                                         cmd_request->bounce_sgl_count);
1726
1727                                         return SCSI_MLQUEUE_DEVICE_BUSY;
1728                         }
1729                 }
1730
1731                 payload->range.len = length;
1732                 payload->range.offset = sgl[0].offset;
1733
1734                 cur_sgl = sgl;
1735                 for (i = 0; i < sg_count; i++) {
1736                         payload->range.pfn_array[i] =
1737                                 page_to_pfn(sg_page((cur_sgl)));
1738                         cur_sgl = sg_next(cur_sgl);
1739                 }
1740
1741         } else if (scsi_sglist(scmnd)) {
1742                 payload->range.len = length;
1743                 payload->range.offset =
1744                         virt_to_phys(scsi_sglist(scmnd)) & (PAGE_SIZE-1);
1745                 payload->range.pfn_array[0] =
1746                         virt_to_phys(scsi_sglist(scmnd)) >> PAGE_SHIFT;
1747         }
1748
1749         cmd_request->payload = payload;
1750         cmd_request->payload_sz = payload_sz;
1751
1752         /* Invokes the vsc to start an IO */
1753         ret = storvsc_do_io(dev, cmd_request);
1754
1755         if (ret == -EAGAIN) {
1756                 /* no more space */
1757
1758                 if (cmd_request->bounce_sgl_count)
1759                         destroy_bounce_buffer(cmd_request->bounce_sgl,
1760                                         cmd_request->bounce_sgl_count);
1761
1762                 return SCSI_MLQUEUE_DEVICE_BUSY;
1763         }
1764
1765         return 0;
1766 }
1767
1768 static struct scsi_host_template scsi_driver = {
1769         .module =               THIS_MODULE,
1770         .name =                 "storvsc_host_t",
1771         .cmd_size =             sizeof(struct storvsc_cmd_request),
1772         .bios_param =           storvsc_get_chs,
1773         .queuecommand =         storvsc_queuecommand,
1774         .eh_host_reset_handler =        storvsc_host_reset_handler,
1775         .proc_name =            "storvsc_host",
1776         .eh_timed_out =         storvsc_eh_timed_out,
1777         .slave_configure =      storvsc_device_configure,
1778         .cmd_per_lun =          255,
1779         .this_id =              -1,
1780         .use_clustering =       ENABLE_CLUSTERING,
1781         /* Make sure we dont get a sg segment crosses a page boundary */
1782         .dma_boundary =         PAGE_SIZE-1,
1783         .no_write_same =        1,
1784 };
1785
1786 enum {
1787         SCSI_GUID,
1788         IDE_GUID,
1789         SFC_GUID,
1790 };
1791
1792 static const struct hv_vmbus_device_id id_table[] = {
1793         /* SCSI guid */
1794         { HV_SCSI_GUID,
1795           .driver_data = SCSI_GUID
1796         },
1797         /* IDE guid */
1798         { HV_IDE_GUID,
1799           .driver_data = IDE_GUID
1800         },
1801         /* Fibre Channel GUID */
1802         {
1803           HV_SYNTHFC_GUID,
1804           .driver_data = SFC_GUID
1805         },
1806         { },
1807 };
1808
1809 MODULE_DEVICE_TABLE(vmbus, id_table);
1810
1811 static int storvsc_probe(struct hv_device *device,
1812                         const struct hv_vmbus_device_id *dev_id)
1813 {
1814         int ret;
1815         int num_cpus = num_online_cpus();
1816         struct Scsi_Host *host;
1817         struct hv_host_device *host_dev;
1818         bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1819         int target = 0;
1820         struct storvsc_device *stor_device;
1821         int max_luns_per_target;
1822         int max_targets;
1823         int max_channels;
1824         int max_sub_channels = 0;
1825
1826         /*
1827          * Based on the windows host we are running on,
1828          * set state to properly communicate with the host.
1829          */
1830
1831         if (vmbus_proto_version < VERSION_WIN8) {
1832                 max_luns_per_target = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1833                 max_targets = STORVSC_IDE_MAX_TARGETS;
1834                 max_channels = STORVSC_IDE_MAX_CHANNELS;
1835         } else {
1836                 max_luns_per_target = STORVSC_MAX_LUNS_PER_TARGET;
1837                 max_targets = STORVSC_MAX_TARGETS;
1838                 max_channels = STORVSC_MAX_CHANNELS;
1839                 /*
1840                  * On Windows8 and above, we support sub-channels for storage.
1841                  * The number of sub-channels offerred is based on the number of
1842                  * VCPUs in the guest.
1843                  */
1844                 max_sub_channels = (num_cpus / storvsc_vcpus_per_sub_channel);
1845         }
1846
1847         scsi_driver.can_queue = (max_outstanding_req_per_channel *
1848                                  (max_sub_channels + 1));
1849
1850         host = scsi_host_alloc(&scsi_driver,
1851                                sizeof(struct hv_host_device));
1852         if (!host)
1853                 return -ENOMEM;
1854
1855         host_dev = shost_priv(host);
1856         memset(host_dev, 0, sizeof(struct hv_host_device));
1857
1858         host_dev->port = host->host_no;
1859         host_dev->dev = device;
1860
1861
1862         stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1863         if (!stor_device) {
1864                 ret = -ENOMEM;
1865                 goto err_out0;
1866         }
1867
1868         stor_device->destroy = false;
1869         stor_device->open_sub_channel = false;
1870         init_waitqueue_head(&stor_device->waiting_to_drain);
1871         stor_device->device = device;
1872         stor_device->host = host;
1873         hv_set_drvdata(device, stor_device);
1874
1875         stor_device->port_number = host->host_no;
1876         ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size);
1877         if (ret)
1878                 goto err_out1;
1879
1880         host_dev->path = stor_device->path_id;
1881         host_dev->target = stor_device->target_id;
1882
1883         switch (dev_id->driver_data) {
1884         case SFC_GUID:
1885                 host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
1886                 host->max_id = STORVSC_FC_MAX_TARGETS;
1887                 host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
1888                 break;
1889
1890         case SCSI_GUID:
1891                 host->max_lun = max_luns_per_target;
1892                 host->max_id = max_targets;
1893                 host->max_channel = max_channels - 1;
1894                 break;
1895
1896         default:
1897                 host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1898                 host->max_id = STORVSC_IDE_MAX_TARGETS;
1899                 host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
1900                 break;
1901         }
1902         /* max cmd length */
1903         host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1904
1905         /*
1906          * set the table size based on the info we got
1907          * from the host.
1908          */
1909         host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT);
1910
1911         /* Register the HBA and start the scsi bus scan */
1912         ret = scsi_add_host(host, &device->device);
1913         if (ret != 0)
1914                 goto err_out2;
1915
1916         if (!dev_is_ide) {
1917                 scsi_scan_host(host);
1918         } else {
1919                 target = (device->dev_instance.b[5] << 8 |
1920                          device->dev_instance.b[4]);
1921                 ret = scsi_add_device(host, 0, target, 0);
1922                 if (ret) {
1923                         scsi_remove_host(host);
1924                         goto err_out2;
1925                 }
1926         }
1927         return 0;
1928
1929 err_out2:
1930         /*
1931          * Once we have connected with the host, we would need to
1932          * to invoke storvsc_dev_remove() to rollback this state and
1933          * this call also frees up the stor_device; hence the jump around
1934          * err_out1 label.
1935          */
1936         storvsc_dev_remove(device);
1937         goto err_out0;
1938
1939 err_out1:
1940         kfree(stor_device);
1941
1942 err_out0:
1943         scsi_host_put(host);
1944         return ret;
1945 }
1946
1947 static int storvsc_remove(struct hv_device *dev)
1948 {
1949         struct storvsc_device *stor_device = hv_get_drvdata(dev);
1950         struct Scsi_Host *host = stor_device->host;
1951
1952         scsi_remove_host(host);
1953         storvsc_dev_remove(dev);
1954         scsi_host_put(host);
1955
1956         return 0;
1957 }
1958
1959 static struct hv_driver storvsc_drv = {
1960         .name = KBUILD_MODNAME,
1961         .id_table = id_table,
1962         .probe = storvsc_probe,
1963         .remove = storvsc_remove,
1964 };
1965
1966 static int __init storvsc_drv_init(void)
1967 {
1968
1969         /*
1970          * Divide the ring buffer data size (which is 1 page less
1971          * than the ring buffer size since that page is reserved for
1972          * the ring buffer indices) by the max request size (which is
1973          * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
1974          */
1975         max_outstanding_req_per_channel =
1976                 ((storvsc_ringbuffer_size - PAGE_SIZE) /
1977                 ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
1978                 sizeof(struct vstor_packet) + sizeof(u64) -
1979                 vmscsi_size_delta,
1980                 sizeof(u64)));
1981
1982         return vmbus_driver_register(&storvsc_drv);
1983 }
1984
1985 static void __exit storvsc_drv_exit(void)
1986 {
1987         vmbus_driver_unregister(&storvsc_drv);
1988 }
1989
1990 MODULE_LICENSE("GPL");
1991 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
1992 module_init(storvsc_drv_init);
1993 module_exit(storvsc_drv_exit);