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.
 155  */
 156 static int sense_buffer_size;
 157
 158 /*
 159  * The size of the vmscsi_request has changed in win8. The
 160  * additional size is because of new elements added to the
 161  * structure. These elements are valid only when we are talking
 162  * to a win8 host.
 163  * Track the correction to size we need to apply.
 164  */
 165
 166 static int vmscsi_size_delta;
 167 static int vmstor_proto_version;
 168
 169 struct vmscsi_win8_extension {
 170         /*
 171          * The following were added in Windows 8
 172          */
 173         u16 reserve;
 174         u8  queue_tag;
 175         u8  queue_action;
 176         u32 srb_flags;
 177         u32 time_out_value;
 178         u32 queue_sort_ey;
 179 } __packed;
 180
 181 struct vmscsi_request {
 182         u16 length;
 183         u8 srb_status;
 184         u8 scsi_status;
 185
 186         u8  port_number;
 187         u8  path_id;
 188         u8  target_id;
 189         u8  lun;
 190
 191         u8  cdb_length;
 192         u8  sense_info_length;
 193         u8  data_in;
 194         u8  reserved;
 195
 196         u32 data_transfer_length;
 197
 198         union {
 199                 u8 cdb[STORVSC_MAX_CMD_LEN];
 200                 u8 sense_data[STORVSC_SENSE_BUFFER_SIZE];
 201                 u8 reserved_array[STORVSC_MAX_BUF_LEN_WITH_PADDING];
 202         };
 203         /*
 204          * The following was added in win8.
 205          */
 206         struct vmscsi_win8_extension win8_extension;
 207
 208 } __attribute((packed));
 209
 210
 211 /*
 212  * The list of storage protocols in order of preference.
 213  */
 214 struct vmstor_protocol {
 215         int protocol_version;
 216         int sense_buffer_size;
 217         int vmscsi_size_delta;
 218 };
 219
 220
 221 static const struct vmstor_protocol vmstor_protocols[] = {
 222         {
 223                 VMSTOR_PROTO_VERSION_WIN10,
 224                 POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
 225                 0
 226         },
 227         {
 228                 VMSTOR_PROTO_VERSION_WIN8_1,
 229                 POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
 230                 0
 231         },
 232         {
 233                 VMSTOR_PROTO_VERSION_WIN8,
 234                 POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
 235                 0
 236         },
 237         {
 238                 VMSTOR_PROTO_VERSION_WIN7,
 239                 PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
 240                 sizeof(struct vmscsi_win8_extension),
 241         },
 242         {
 243                 VMSTOR_PROTO_VERSION_WIN6,
 244                 PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
 245                 sizeof(struct vmscsi_win8_extension),
 246         }
 247 };
 248
 249
 250 /*
 251  * This structure is sent during the intialization phase to get the different
 252  * properties of the channel.
 253  */
 254
 255 #define STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL          0x1
 256
 257 struct vmstorage_channel_properties {
 258         u32 reserved;
 259         u16 max_channel_cnt;
 260         u16 reserved1;
 261
 262         u32 flags;
 263         u32   max_transfer_bytes;
 264
 265         u64  reserved2;
 266 } __packed;
 267
 268 /*  This structure is sent during the storage protocol negotiations. */
 269 struct vmstorage_protocol_version {
 270         /* Major (MSW) and minor (LSW) version numbers. */
 271         u16 major_minor;
 272
 273         /*
 274          * Revision number is auto-incremented whenever this file is changed
 275          * (See FILL_VMSTOR_REVISION macro above).  Mismatch does not
 276          * definitely indicate incompatibility--but it does indicate mismatched
 277          * builds.
 278          * This is only used on the windows side. Just set it to 0.
 279          */
 280         u16 revision;
 281 } __packed;
 282
 283 /* Channel Property Flags */
 284 #define STORAGE_CHANNEL_REMOVABLE_FLAG          0x1
 285 #define STORAGE_CHANNEL_EMULATED_IDE_FLAG       0x2
 286
 287 struct vstor_packet {
 288         /* Requested operation type */
 289         enum vstor_packet_operation operation;
 290
 291         /*  Flags - see below for values */
 292         u32 flags;
 293
 294         /* Status of the request returned from the server side. */
 295         u32 status;
 296
 297         /* Data payload area */
 298         union {
 299                 /*
 300                  * Structure used to forward SCSI commands from the
 301                  * client to the server.
 302                  */
 303                 struct vmscsi_request vm_srb;
 304
 305                 /* Structure used to query channel properties. */
 306                 struct vmstorage_channel_properties storage_channel_properties;
 307
 308                 /* Used during version negotiations. */
 309                 struct vmstorage_protocol_version version;
 310
 311                 /* Fibre channel address packet */
 312                 struct hv_fc_wwn_packet wwn_packet;
 313
 314                 /* Number of sub-channels to create */
 315                 u16 sub_channel_count;
 316
 317                 /* This will be the maximum of the union members */
 318                 u8  buffer[0x34];
 319         };
 320 } __packed;
 321
 322 /*
 323  * Packet Flags:
 324  *
 325  * This flag indicates that the server should send back a completion for this
 326  * packet.
 327  */
 328
 329 #define REQUEST_COMPLETION_FLAG 0x1
 330
 331 /* Matches Windows-end */
 332 enum storvsc_request_type {
 333         WRITE_TYPE = 0,
 334         READ_TYPE,
 335         UNKNOWN_TYPE,
 336 };
 337
 338 /*
 339  * SRB status codes and masks; a subset of the codes used here.
 340  */
 341
 342 #define SRB_STATUS_AUTOSENSE_VALID      0x80
 343 #define SRB_STATUS_INVALID_LUN  0x20
 344 #define SRB_STATUS_SUCCESS      0x01
 345 #define SRB_STATUS_ABORTED      0x02
 346 #define SRB_STATUS_ERROR        0x04
 347
 348 /*
 349  * This is the end of Protocol specific defines.
 350  */
 351
 352 static int storvsc_ringbuffer_size = (256 * PAGE_SIZE);
 353 static u32 max_outstanding_req_per_channel;
 354
 355 static int storvsc_vcpus_per_sub_channel = 4;
 356
 357 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
 358 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
 359
 360 module_param(storvsc_vcpus_per_sub_channel, int, S_IRUGO);
 361 MODULE_PARM_DESC(vcpus_per_sub_channel, "Ratio of VCPUs to subchannels");
 362 /*
 363  * Timeout in seconds for all devices managed by this driver.
 364  */
 365 static int storvsc_timeout = 180;
 366
 367 static int msft_blist_flags = BLIST_TRY_VPD_PAGES;
 368
 369
 370 static void storvsc_on_channel_callback(void *context);
 371
 372 #define STORVSC_MAX_LUNS_PER_TARGET                     255
 373 #define STORVSC_MAX_TARGETS                             2
 374 #define STORVSC_MAX_CHANNELS                            8
 375
 376 #define STORVSC_FC_MAX_LUNS_PER_TARGET                  255
 377 #define STORVSC_FC_MAX_TARGETS                          128
 378 #define STORVSC_FC_MAX_CHANNELS                         8
 379
 380 #define STORVSC_IDE_MAX_LUNS_PER_TARGET                 64
 381 #define STORVSC_IDE_MAX_TARGETS                         1
 382 #define STORVSC_IDE_MAX_CHANNELS                        1
 383
 384 struct storvsc_cmd_request {
 385         struct scsi_cmnd *cmd;
 386
 387         unsigned int bounce_sgl_count;
 388         struct scatterlist *bounce_sgl;
 389
 390         struct hv_device *device;
 391
 392         /* Synchronize the request/response if needed */
 393         struct completion wait_event;
 394
 395         struct vmbus_channel_packet_multipage_buffer mpb;
 396         struct vmbus_packet_mpb_array *payload;
 397         u32 payload_sz;
 398
 399         struct vstor_packet vstor_packet;
 400 };
 401
 402
 403 /* A storvsc device is a device object that contains a vmbus channel */
 404 struct storvsc_device {
 405         struct hv_device *device;
 406
 407         bool     destroy;
 408         bool     drain_notify;
 409         bool     open_sub_channel;
 410         atomic_t num_outstanding_req;
 411         struct Scsi_Host *host;
 412
 413         wait_queue_head_t waiting_to_drain;
 414
 415         /*
 416          * Each unique Port/Path/Target represents 1 channel ie scsi
 417          * controller. In reality, the pathid, targetid is always 0
 418          * and the port is set by us
 419          */
 420         unsigned int port_number;
 421         unsigned char path_id;
 422         unsigned char target_id;
 423
 424         /*
 425          * Max I/O, the device can support.
 426          */
 427         u32   max_transfer_bytes;
 428         /* Used for vsc/vsp channel reset process */
 429         struct storvsc_cmd_request init_request;
 430         struct storvsc_cmd_request reset_request;
 431 };
 432
 433 struct hv_host_device {
 434         struct hv_device *dev;
 435         unsigned int port;
 436         unsigned char path;
 437         unsigned char target;
 438 };
 439
 440 struct storvsc_scan_work {
 441         struct work_struct work;
 442         struct Scsi_Host *host;
 443         uint lun;
 444 };
 445
 446 static void storvsc_device_scan(struct work_struct *work)
 447 {
 448         struct storvsc_scan_work *wrk;
 449         uint lun;
 450         struct scsi_device *sdev;
 451
 452         wrk = container_of(work, struct storvsc_scan_work, work);
 453         lun = wrk->lun;
 454
 455         sdev = scsi_device_lookup(wrk->host, 0, 0, lun);
 456         if (!sdev)
 457                 goto done;
 458         scsi_rescan_device(&sdev->sdev_gendev);
 459         scsi_device_put(sdev);
 460
 461 done:
 462         kfree(wrk);
 463 }
 464
 465 static void storvsc_host_scan(struct work_struct *work)
 466 {
 467         struct storvsc_scan_work *wrk;
 468         struct Scsi_Host *host;
 469         struct scsi_device *sdev;
 470
 471         wrk = container_of(work, struct storvsc_scan_work, work);
 472         host = wrk->host;
 473
 474         /*
 475          * Before scanning the host, first check to see if any of the
 476          * currrently known devices have been hot removed. We issue a
 477          * "unit ready" command against all currently known devices.
 478          * This I/O will result in an error for devices that have been
 479          * removed. As part of handling the I/O error, we remove the device.
 480          *
 481          * When a LUN is added or removed, the host sends us a signal to
 482          * scan the host. Thus we are forced to discover the LUNs that
 483          * may have been removed this way.
 484          */
 485         mutex_lock(&host->scan_mutex);
 486         shost_for_each_device(sdev, host)
 487                 scsi_test_unit_ready(sdev, 1, 1, NULL);
 488         mutex_unlock(&host->scan_mutex);
 489         /*
 490          * Now scan the host to discover LUNs that may have been added.
 491          */
 492         scsi_scan_host(host);
 493
 494         kfree(wrk);
 495 }
 496
 497 static void storvsc_remove_lun(struct work_struct *work)
 498 {
 499         struct storvsc_scan_work *wrk;
 500         struct scsi_device *sdev;
 501
 502         wrk = container_of(work, struct storvsc_scan_work, work);
 503         if (!scsi_host_get(wrk->host))
 504                 goto done;
 505
 506         sdev = scsi_device_lookup(wrk->host, 0, 0, wrk->lun);
 507
 508         if (sdev) {
 509                 scsi_remove_device(sdev);
 510                 scsi_device_put(sdev);
 511         }
 512         scsi_host_put(wrk->host);
 513
 514 done:
 515         kfree(wrk);
 516 }
 517
 518
 519 /*
 520  * We can get incoming messages from the host that are not in response to
 521  * messages that we have sent out. An example of this would be messages
 522  * received by the guest to notify dynamic addition/removal of LUNs. To
 523  * deal with potential race conditions where the driver may be in the
 524  * midst of being unloaded when we might receive an unsolicited message
 525  * from the host, we have implemented a mechanism to gurantee sequential
 526  * consistency:
 527  *
 528  * 1) Once the device is marked as being destroyed, we will fail all
 529  *    outgoing messages.
 530  * 2) We permit incoming messages when the device is being destroyed,
 531  *    only to properly account for messages already sent out.
 532  */
 533
 534 static inline struct storvsc_device *get_out_stor_device(
 535                                         struct hv_device *device)
 536 {
 537         struct storvsc_device *stor_device;
 538
 539         stor_device = hv_get_drvdata(device);
 540
 541         if (stor_device && stor_device->destroy)
 542                 stor_device = NULL;
 543
 544         return stor_device;
 545 }
 546
 547
 548 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
 549 {
 550         dev->drain_notify = true;
 551         wait_event(dev->waiting_to_drain,
 552                    atomic_read(&dev->num_outstanding_req) == 0);
 553         dev->drain_notify = false;
 554 }
 555
 556 static inline struct storvsc_device *get_in_stor_device(
 557                                         struct hv_device *device)
 558 {
 559         struct storvsc_device *stor_device;
 560
 561         stor_device = hv_get_drvdata(device);
 562
 563         if (!stor_device)
 564                 goto get_in_err;
 565
 566         /*
 567          * If the device is being destroyed; allow incoming
 568          * traffic only to cleanup outstanding requests.
 569          */
 570
 571         if (stor_device->destroy  &&
 572                 (atomic_read(&stor_device->num_outstanding_req) == 0))
 573                 stor_device = NULL;
 574
 575 get_in_err:
 576         return stor_device;
 577
 578 }
 579
 580 static void destroy_bounce_buffer(struct scatterlist *sgl,
 581                                   unsigned int sg_count)
 582 {
 583         int i;
 584         struct page *page_buf;
 585
 586         for (i = 0; i < sg_count; i++) {
 587                 page_buf = sg_page((&sgl[i]));
 588                 if (page_buf != NULL)
 589                         __free_page(page_buf);
 590         }
 591
 592         kfree(sgl);
 593 }
 594
 595 static int do_bounce_buffer(struct scatterlist *sgl, unsigned int sg_count)
 596 {
 597         int i;
 598
 599         /* No need to check */
 600         if (sg_count < 2)
 601                 return -1;
 602
 603         /* We have at least 2 sg entries */
 604         for (i = 0; i < sg_count; i++) {
 605                 if (i == 0) {
 606                         /* make sure 1st one does not have hole */
 607                         if (sgl[i].offset + sgl[i].length != PAGE_SIZE)
 608                                 return i;
 609                 } else if (i == sg_count - 1) {
 610                         /* make sure last one does not have hole */
 611                         if (sgl[i].offset != 0)
 612                                 return i;
 613                 } else {
 614                         /* make sure no hole in the middle */
 615                         if (sgl[i].length != PAGE_SIZE || sgl[i].offset != 0)
 616                                 return i;
 617                 }
 618         }
 619         return -1;
 620 }
 621
 622 static struct scatterlist *create_bounce_buffer(struct scatterlist *sgl,
 623                                                 unsigned int sg_count,
 624                                                 unsigned int len,
 625                                                 int write)
 626 {
 627         int i;
 628         int num_pages;
 629         struct scatterlist *bounce_sgl;
 630         struct page *page_buf;
 631         unsigned int buf_len = ((write == WRITE_TYPE) ? 0 : PAGE_SIZE);
 632
 633         num_pages = ALIGN(len, PAGE_SIZE) >> PAGE_SHIFT;
 634
 635         bounce_sgl = kcalloc(num_pages, sizeof(struct scatterlist), GFP_ATOMIC);
 636         if (!bounce_sgl)
 637                 return NULL;
 638
 639         sg_init_table(bounce_sgl, num_pages);
 640         for (i = 0; i < num_pages; i++) {
 641                 page_buf = alloc_page(GFP_ATOMIC);
 642                 if (!page_buf)
 643                         goto cleanup;
 644                 sg_set_page(&bounce_sgl[i], page_buf, buf_len, 0);
 645         }
 646
 647         return bounce_sgl;
 648
 649 cleanup:
 650         destroy_bounce_buffer(bounce_sgl, num_pages);
 651         return NULL;
 652 }
 653
 654 /* Assume the original sgl has enough room */
 655 static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl,
 656                                             struct scatterlist *bounce_sgl,
 657                                             unsigned int orig_sgl_count,
 658                                             unsigned int bounce_sgl_count)
 659 {
 660         int i;
 661         int j = 0;
 662         unsigned long src, dest;
 663         unsigned int srclen, destlen, copylen;
 664         unsigned int total_copied = 0;
 665         unsigned long bounce_addr = 0;
 666         unsigned long dest_addr = 0;
 667         unsigned long flags;
 668         struct scatterlist *cur_dest_sgl;
 669         struct scatterlist *cur_src_sgl;
 670
 671         local_irq_save(flags);
 672         cur_dest_sgl = orig_sgl;
 673         cur_src_sgl = bounce_sgl;
 674         for (i = 0; i < orig_sgl_count; i++) {
 675                 dest_addr = (unsigned long)
 676                                 kmap_atomic(sg_page(cur_dest_sgl)) +
 677                                 cur_dest_sgl->offset;
 678                 dest = dest_addr;
 679                 destlen = cur_dest_sgl->length;
 680
 681                 if (bounce_addr == 0)
 682                         bounce_addr = (unsigned long)kmap_atomic(
 683                                                         sg_page(cur_src_sgl));
 684
 685                 while (destlen) {
 686                         src = bounce_addr + cur_src_sgl->offset;
 687                         srclen = cur_src_sgl->length - cur_src_sgl->offset;
 688
 689                         copylen = min(srclen, destlen);
 690                         memcpy((void *)dest, (void *)src, copylen);
 691
 692                         total_copied += copylen;
 693                         cur_src_sgl->offset += copylen;
 694                         destlen -= copylen;
 695                         dest += copylen;
 696
 697                         if (cur_src_sgl->offset == cur_src_sgl->length) {
 698                                 /* full */
 699                                 kunmap_atomic((void *)bounce_addr);
 700                                 j++;
 701
 702                                 /*
 703                                  * It is possible that the number of elements
 704                                  * in the bounce buffer may not be equal to
 705                                  * the number of elements in the original
 706                                  * scatter list. Handle this correctly.
 707                                  */
 708
 709                                 if (j == bounce_sgl_count) {
 710                                         /*
 711                                          * We are done; cleanup and return.
 712                                          */
 713                                         kunmap_atomic((void *)(dest_addr -
 714                                                 cur_dest_sgl->offset));
 715                                         local_irq_restore(flags);
 716                                         return total_copied;
 717                                 }
 718
 719                                 /* if we need to use another bounce buffer */
 720                                 if (destlen || i != orig_sgl_count - 1) {
 721                                         cur_src_sgl = sg_next(cur_src_sgl);
 722                                         bounce_addr = (unsigned long)
 723                                                         kmap_atomic(
 724                                                         sg_page(cur_src_sgl));
 725                                 }
 726                         } else if (destlen == 0 && i == orig_sgl_count - 1) {
 727                                 /* unmap the last bounce that is < PAGE_SIZE */
 728                                 kunmap_atomic((void *)bounce_addr);
 729                         }
 730                 }
 731
 732                 kunmap_atomic((void *)(dest_addr - cur_dest_sgl->offset));
 733                 cur_dest_sgl = sg_next(cur_dest_sgl);
 734         }
 735
 736         local_irq_restore(flags);
 737
 738         return total_copied;
 739 }
 740
 741 /* Assume the bounce_sgl has enough room ie using the create_bounce_buffer() */
 742 static unsigned int copy_to_bounce_buffer(struct scatterlist *orig_sgl,
 743                                           struct scatterlist *bounce_sgl,
 744                                           unsigned int orig_sgl_count)
 745 {
 746         int i;
 747         int j = 0;
 748         unsigned long src, dest;
 749         unsigned int srclen, destlen, copylen;
 750         unsigned int total_copied = 0;
 751         unsigned long bounce_addr = 0;
 752         unsigned long src_addr = 0;
 753         unsigned long flags;
 754         struct scatterlist *cur_src_sgl;
 755         struct scatterlist *cur_dest_sgl;
 756
 757         local_irq_save(flags);
 758
 759         cur_src_sgl = orig_sgl;
 760         cur_dest_sgl = bounce_sgl;
 761
 762         for (i = 0; i < orig_sgl_count; i++) {
 763                 src_addr = (unsigned long)
 764                                 kmap_atomic(sg_page(cur_src_sgl)) +
 765                                 cur_src_sgl->offset;
 766                 src = src_addr;
 767                 srclen = cur_src_sgl->length;
 768
 769                 if (bounce_addr == 0)
 770                         bounce_addr = (unsigned long)
 771                                         kmap_atomic(sg_page(cur_dest_sgl));
 772
 773                 while (srclen) {
 774                         /* assume bounce offset always == 0 */
 775                         dest = bounce_addr + cur_dest_sgl->length;
 776                         destlen = PAGE_SIZE - cur_dest_sgl->length;
 777
 778                         copylen = min(srclen, destlen);
 779                         memcpy((void *)dest, (void *)src, copylen);
 780
 781                         total_copied += copylen;
 782                         cur_dest_sgl->length += copylen;
 783                         srclen -= copylen;
 784                         src += copylen;
 785
 786                         if (cur_dest_sgl->length == PAGE_SIZE) {
 787                                 /* full..move to next entry */
 788                                 kunmap_atomic((void *)bounce_addr);
 789                                 bounce_addr = 0;
 790                                 j++;
 791                         }
 792
 793                         /* if we need to use another bounce buffer */
 794                         if (srclen && bounce_addr == 0) {
 795                                 cur_dest_sgl = sg_next(cur_dest_sgl);
 796                                 bounce_addr = (unsigned long)
 797                                                 kmap_atomic(
 798                                                 sg_page(cur_dest_sgl));
 799                         }
 800
 801                 }
 802
 803                 kunmap_atomic((void *)(src_addr - cur_src_sgl->offset));
 804                 cur_src_sgl = sg_next(cur_src_sgl);
 805         }
 806
 807         if (bounce_addr)
 808                 kunmap_atomic((void *)bounce_addr);
 809
 810         local_irq_restore(flags);
 811
 812         return total_copied;
 813 }
 814
 815 static void handle_sc_creation(struct vmbus_channel *new_sc)
 816 {
 817         struct hv_device *device = new_sc->primary_channel->device_obj;
 818         struct storvsc_device *stor_device;
 819         struct vmstorage_channel_properties props;
 820
 821         stor_device = get_out_stor_device(device);
 822         if (!stor_device)
 823                 return;
 824
 825         if (stor_device->open_sub_channel == false)
 826                 return;
 827
 828         memset(&props, 0, sizeof(struct vmstorage_channel_properties));
 829
 830         vmbus_open(new_sc,
 831                    storvsc_ringbuffer_size,
 832                    storvsc_ringbuffer_size,
 833                    (void *)&props,
 834                    sizeof(struct vmstorage_channel_properties),
 835                    storvsc_on_channel_callback, new_sc);
 836 }
 837
 838 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
 839 {
 840         struct storvsc_device *stor_device;
 841         int num_cpus = num_online_cpus();
 842         int num_sc;
 843         struct storvsc_cmd_request *request;
 844         struct vstor_packet *vstor_packet;
 845         int ret, t;
 846
 847         num_sc = ((max_chns > num_cpus) ? num_cpus : max_chns);
 848         stor_device = get_out_stor_device(device);
 849         if (!stor_device)
 850                 return;
 851
 852         request = &stor_device->init_request;
 853         vstor_packet = &request->vstor_packet;
 854
 855         stor_device->open_sub_channel = true;
 856         /*
 857          * Establish a handler for dealing with subchannels.
 858          */
 859         vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
 860
 861         /*
 862          * Check to see if sub-channels have already been created. This
 863          * can happen when this driver is re-loaded after unloading.
 864          */
 865
 866         if (vmbus_are_subchannels_present(device->channel))
 867                 return;
 868
 869         stor_device->open_sub_channel = false;
 870         /*
 871          * Request the host to create sub-channels.
 872          */
 873         memset(request, 0, sizeof(struct storvsc_cmd_request));
 874         init_completion(&request->wait_event);
 875         vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
 876         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 877         vstor_packet->sub_channel_count = num_sc;
 878
 879         ret = vmbus_sendpacket(device->channel, vstor_packet,
 880                                (sizeof(struct vstor_packet) -
 881                                vmscsi_size_delta),
 882                                (unsigned long)request,
 883                                VM_PKT_DATA_INBAND,
 884                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 885
 886         if (ret != 0)
 887                 return;
 888
 889         t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
 890         if (t == 0)
 891                 return;
 892
 893         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
 894             vstor_packet->status != 0)
 895                 return;
 896
 897         /*
 898          * Now that we created the sub-channels, invoke the check; this
 899          * may trigger the callback.
 900          */
 901         stor_device->open_sub_channel = true;
 902         vmbus_are_subchannels_present(device->channel);
 903 }
 904
 905 static int storvsc_channel_init(struct hv_device *device)
 906 {
 907         struct storvsc_device *stor_device;
 908         struct storvsc_cmd_request *request;
 909         struct vstor_packet *vstor_packet;
 910         int ret, t, i;
 911         int max_chns;
 912         bool process_sub_channels = false;
 913
 914         stor_device = get_out_stor_device(device);
 915         if (!stor_device)
 916                 return -ENODEV;
 917
 918         request = &stor_device->init_request;
 919         vstor_packet = &request->vstor_packet;
 920
 921         /*
 922          * Now, initiate the vsc/vsp initialization protocol on the open
 923          * channel
 924          */
 925         memset(request, 0, sizeof(struct storvsc_cmd_request));
 926         init_completion(&request->wait_event);
 927         vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
 928         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 929
 930         ret = vmbus_sendpacket(device->channel, vstor_packet,
 931                                (sizeof(struct vstor_packet) -
 932                                vmscsi_size_delta),
 933                                (unsigned long)request,
 934                                VM_PKT_DATA_INBAND,
 935                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 936         if (ret != 0)
 937                 goto cleanup;
 938
 939         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
 940         if (t == 0) {
 941                 ret = -ETIMEDOUT;
 942                 goto cleanup;
 943         }
 944
 945         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
 946             vstor_packet->status != 0)
 947                 goto cleanup;
 948
 949
 950         for (i = 0; i < ARRAY_SIZE(vmstor_protocols); i++) {
 951                 /* reuse the packet for version range supported */
 952                 memset(vstor_packet, 0, sizeof(struct vstor_packet));
 953                 vstor_packet->operation =
 954                         VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
 955                 vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 956
 957                 vstor_packet->version.major_minor =
 958                         vmstor_protocols[i].protocol_version;
 959
 960                 /*
 961                  * The revision number is only used in Windows; set it to 0.
 962                  */
 963                 vstor_packet->version.revision = 0;
 964
 965                 ret = vmbus_sendpacket(device->channel, vstor_packet,
 966                                (sizeof(struct vstor_packet) -
 967                                 vmscsi_size_delta),
 968                                (unsigned long)request,
 969                                VM_PKT_DATA_INBAND,
 970                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 971                 if (ret != 0)
 972                         goto cleanup;
 973
 974                 t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
 975                 if (t == 0) {
 976                         ret = -ETIMEDOUT;
 977                         goto cleanup;
 978                 }
 979
 980                 if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO) {
 981                         ret = -EINVAL;
 982                         goto cleanup;
 983                 }
 984
 985                 if (vstor_packet->status == 0) {
 986                         vmstor_proto_version =
 987                                 vmstor_protocols[i].protocol_version;
 988
 989                         sense_buffer_size =
 990                                 vmstor_protocols[i].sense_buffer_size;
 991
 992                         vmscsi_size_delta =
 993                                 vmstor_protocols[i].vmscsi_size_delta;
 994
 995                         break;
 996                 }
 997         }
 998
 999         if (vstor_packet->status != 0) {
1000                 ret = -EINVAL;
1001                 goto cleanup;
1002         }
1003
1004
1005         memset(vstor_packet, 0, sizeof(struct vstor_packet));
1006         vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
1007         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1008
1009         ret = vmbus_sendpacket(device->channel, vstor_packet,
1010                                (sizeof(struct vstor_packet) -
1011                                 vmscsi_size_delta),
1012                                (unsigned long)request,
1013                                VM_PKT_DATA_INBAND,
1014                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1015
1016         if (ret != 0)
1017                 goto cleanup;
1018
1019         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1020         if (t == 0) {
1021                 ret = -ETIMEDOUT;
1022                 goto cleanup;
1023         }
1024
1025         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
1026             vstor_packet->status != 0)
1027                 goto cleanup;
1028
1029         /*
1030          * Check to see if multi-channel support is there.
1031          * Hosts that implement protocol version of 5.1 and above
1032          * support multi-channel.
1033          */
1034         max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
1035         if (vmbus_proto_version >= VERSION_WIN8) {
1036                 if (vstor_packet->storage_channel_properties.flags &
1037                     STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
1038                         process_sub_channels = true;
1039         }
1040         stor_device->max_transfer_bytes =
1041                 vstor_packet->storage_channel_properties.max_transfer_bytes;
1042
1043         memset(vstor_packet, 0, sizeof(struct vstor_packet));
1044         vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
1045         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1046
1047         ret = vmbus_sendpacket(device->channel, vstor_packet,
1048                                (sizeof(struct vstor_packet) -
1049                                 vmscsi_size_delta),
1050                                (unsigned long)request,
1051                                VM_PKT_DATA_INBAND,
1052                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1053
1054         if (ret != 0)
1055                 goto cleanup;
1056
1057         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1058         if (t == 0) {
1059                 ret = -ETIMEDOUT;
1060                 goto cleanup;
1061         }
1062
1063         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
1064             vstor_packet->status != 0)
1065                 goto cleanup;
1066
1067         if (process_sub_channels)
1068                 handle_multichannel_storage(device, max_chns);
1069
1070
1071 cleanup:
1072         return ret;
1073 }
1074
1075 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
1076                                 struct scsi_cmnd *scmnd,
1077                                 struct Scsi_Host *host,
1078                                 u8 asc, u8 ascq)
1079 {
1080         struct storvsc_scan_work *wrk;
1081         void (*process_err_fn)(struct work_struct *work);
1082         bool do_work = false;
1083
1084         switch (vm_srb->srb_status) {
1085         case SRB_STATUS_ERROR:
1086                 /*
1087                  * If there is an error; offline the device since all
1088                  * error recovery strategies would have already been
1089                  * deployed on the host side. However, if the command
1090                  * were a pass-through command deal with it appropriately.
1091                  */
1092                 switch (scmnd->cmnd[0]) {
1093                 case ATA_16:
1094                 case ATA_12:
1095                         set_host_byte(scmnd, DID_PASSTHROUGH);
1096                         break;
1097                 /*
1098                  * On Some Windows hosts TEST_UNIT_READY command can return
1099                  * SRB_STATUS_ERROR, let the upper level code deal with it
1100                  * based on the sense information.
1101                  */
1102                 case TEST_UNIT_READY:
1103                         break;
1104                 default:
1105                         set_host_byte(scmnd, DID_TARGET_FAILURE);
1106                 }
1107                 break;
1108         case SRB_STATUS_INVALID_LUN:
1109                 do_work = true;
1110                 process_err_fn = storvsc_remove_lun;
1111                 break;
1112         case (SRB_STATUS_ABORTED | SRB_STATUS_AUTOSENSE_VALID):
1113                 if ((asc == 0x2a) && (ascq == 0x9)) {
1114                         do_work = true;
1115                         process_err_fn = storvsc_device_scan;
1116                         /*
1117                          * Retry the I/O that trigerred this.
1118                          */
1119                         set_host_byte(scmnd, DID_REQUEUE);
1120                 }
1121                 break;
1122         }
1123
1124         if (!do_work)
1125                 return;
1126
1127         /*
1128          * We need to schedule work to process this error; schedule it.
1129          */
1130         wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1131         if (!wrk) {
1132                 set_host_byte(scmnd, DID_TARGET_FAILURE);
1133                 return;
1134         }
1135
1136         wrk->host = host;
1137         wrk->lun = vm_srb->lun;
1138         INIT_WORK(&wrk->work, process_err_fn);
1139         schedule_work(&wrk->work);
1140 }
1141
1142
1143 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request)
1144 {
1145         struct scsi_cmnd *scmnd = cmd_request->cmd;
1146         struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1147         struct scsi_sense_hdr sense_hdr;
1148         struct vmscsi_request *vm_srb;
1149         struct Scsi_Host *host;
1150         struct storvsc_device *stor_dev;
1151         struct hv_device *dev = host_dev->dev;
1152         u32 payload_sz = cmd_request->payload_sz;
1153         void *payload = cmd_request->payload;
1154
1155         stor_dev = get_in_stor_device(dev);
1156         host = stor_dev->host;
1157
1158         vm_srb = &cmd_request->vstor_packet.vm_srb;
1159         if (cmd_request->bounce_sgl_count) {
1160                 if (vm_srb->data_in == READ_TYPE)
1161                         copy_from_bounce_buffer(scsi_sglist(scmnd),
1162                                         cmd_request->bounce_sgl,
1163                                         scsi_sg_count(scmnd),
1164                                         cmd_request->bounce_sgl_count);
1165                 destroy_bounce_buffer(cmd_request->bounce_sgl,
1166                                         cmd_request->bounce_sgl_count);
1167         }
1168
1169         scmnd->result = vm_srb->scsi_status;
1170
1171         if (scmnd->result) {
1172                 if (scsi_normalize_sense(scmnd->sense_buffer,
1173                                 SCSI_SENSE_BUFFERSIZE, &sense_hdr))
1174                         scsi_print_sense_hdr(scmnd->device, "storvsc",
1175                                              &sense_hdr);
1176         }
1177
1178         if (vm_srb->srb_status != SRB_STATUS_SUCCESS)
1179                 storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
1180                                          sense_hdr.ascq);
1181
1182         scsi_set_resid(scmnd,
1183                 cmd_request->payload->range.len -
1184                 vm_srb->data_transfer_length);
1185
1186         scmnd->scsi_done(scmnd);
1187
1188         if (payload_sz >
1189                 sizeof(struct vmbus_channel_packet_multipage_buffer))
1190                 kfree(payload);
1191 }
1192
1193 static void storvsc_on_io_completion(struct hv_device *device,
1194                                   struct vstor_packet *vstor_packet,
1195                                   struct storvsc_cmd_request *request)
1196 {
1197         struct storvsc_device *stor_device;
1198         struct vstor_packet *stor_pkt;
1199
1200         stor_device = hv_get_drvdata(device);
1201         stor_pkt = &request->vstor_packet;
1202
1203         /*
1204          * The current SCSI handling on the host side does
1205          * not correctly handle:
1206          * INQUIRY command with page code parameter set to 0x80
1207          * MODE_SENSE command with cmd[2] == 0x1c
1208          *
1209          * Setup srb and scsi status so this won't be fatal.
1210          * We do this so we can distinguish truly fatal failues
1211          * (srb status == 0x4) and off-line the device in that case.
1212          */
1213
1214         if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1215            (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1216                 vstor_packet->vm_srb.scsi_status = 0;
1217                 vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1218         }
1219
1220
1221         /* Copy over the status...etc */
1222         stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1223         stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1224         stor_pkt->vm_srb.sense_info_length =
1225         vstor_packet->vm_srb.sense_info_length;
1226
1227
1228         if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
1229                 /* CHECK_CONDITION */
1230                 if (vstor_packet->vm_srb.srb_status &
1231                         SRB_STATUS_AUTOSENSE_VALID) {
1232                         /* autosense data available */
1233
1234                         memcpy(request->cmd->sense_buffer,
1235                                vstor_packet->vm_srb.sense_data,
1236                                vstor_packet->vm_srb.sense_info_length);
1237
1238                 }
1239         }
1240
1241         stor_pkt->vm_srb.data_transfer_length =
1242         vstor_packet->vm_srb.data_transfer_length;
1243
1244         storvsc_command_completion(request);
1245
1246         if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1247                 stor_device->drain_notify)
1248                 wake_up(&stor_device->waiting_to_drain);
1249
1250
1251 }
1252
1253 static void storvsc_on_receive(struct hv_device *device,
1254                              struct vstor_packet *vstor_packet,
1255                              struct storvsc_cmd_request *request)
1256 {
1257         struct storvsc_scan_work *work;
1258         struct storvsc_device *stor_device;
1259
1260         switch (vstor_packet->operation) {
1261         case VSTOR_OPERATION_COMPLETE_IO:
1262                 storvsc_on_io_completion(device, vstor_packet, request);
1263                 break;
1264
1265         case VSTOR_OPERATION_REMOVE_DEVICE:
1266         case VSTOR_OPERATION_ENUMERATE_BUS:
1267                 stor_device = get_in_stor_device(device);
1268                 work = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1269                 if (!work)
1270                         return;
1271
1272                 INIT_WORK(&work->work, storvsc_host_scan);
1273                 work->host = stor_device->host;
1274                 schedule_work(&work->work);
1275                 break;
1276
1277         default:
1278                 break;
1279         }
1280 }
1281
1282 static void storvsc_on_channel_callback(void *context)
1283 {
1284         struct vmbus_channel *channel = (struct vmbus_channel *)context;
1285         struct hv_device *device;
1286         struct storvsc_device *stor_device;
1287         u32 bytes_recvd;
1288         u64 request_id;
1289         unsigned char packet[ALIGN(sizeof(struct vstor_packet), 8)];
1290         struct storvsc_cmd_request *request;
1291         int ret;
1292
1293         if (channel->primary_channel != NULL)
1294                 device = channel->primary_channel->device_obj;
1295         else
1296                 device = channel->device_obj;
1297
1298         stor_device = get_in_stor_device(device);
1299         if (!stor_device)
1300                 return;
1301
1302         do {
1303                 ret = vmbus_recvpacket(channel, packet,
1304                                        ALIGN((sizeof(struct vstor_packet) -
1305                                              vmscsi_size_delta), 8),
1306                                        &bytes_recvd, &request_id);
1307                 if (ret == 0 && bytes_recvd > 0) {
1308
1309                         request = (struct storvsc_cmd_request *)
1310                                         (unsigned long)request_id;
1311
1312                         if ((request == &stor_device->init_request) ||
1313                             (request == &stor_device->reset_request)) {
1314
1315                                 memcpy(&request->vstor_packet, packet,
1316                                        (sizeof(struct vstor_packet) -
1317                                         vmscsi_size_delta));
1318                                 complete(&request->wait_event);
1319                         } else {
1320                                 storvsc_on_receive(device,
1321                                                 (struct vstor_packet *)packet,
1322                                                 request);
1323                         }
1324                 } else {
1325                         break;
1326                 }
1327         } while (1);
1328
1329         return;
1330 }
1331
1332 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size)
1333 {
1334         struct vmstorage_channel_properties props;
1335         int ret;
1336
1337         memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1338
1339         ret = vmbus_open(device->channel,
1340                          ring_size,
1341                          ring_size,
1342                          (void *)&props,
1343                          sizeof(struct vmstorage_channel_properties),
1344                          storvsc_on_channel_callback, device->channel);
1345
1346         if (ret != 0)
1347                 return ret;
1348
1349         ret = storvsc_channel_init(device);
1350
1351         return ret;
1352 }
1353
1354 static int storvsc_dev_remove(struct hv_device *device)
1355 {
1356         struct storvsc_device *stor_device;
1357         unsigned long flags;
1358
1359         stor_device = hv_get_drvdata(device);
1360
1361         spin_lock_irqsave(&device->channel->inbound_lock, flags);
1362         stor_device->destroy = true;
1363         spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
1364
1365         /*
1366          * At this point, all outbound traffic should be disable. We
1367          * only allow inbound traffic (responses) to proceed so that
1368          * outstanding requests can be completed.
1369          */
1370
1371         storvsc_wait_to_drain(stor_device);
1372
1373         /*
1374          * Since we have already drained, we don't need to busy wait
1375          * as was done in final_release_stor_device()
1376          * Note that we cannot set the ext pointer to NULL until
1377          * we have drained - to drain the outgoing packets, we need to
1378          * allow incoming packets.
1379          */
1380         spin_lock_irqsave(&device->channel->inbound_lock, flags);
1381         hv_set_drvdata(device, NULL);
1382         spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
1383
1384         /* Close the channel */
1385         vmbus_close(device->channel);
1386
1387         kfree(stor_device);
1388         return 0;
1389 }
1390
1391 static int storvsc_do_io(struct hv_device *device,
1392                          struct storvsc_cmd_request *request)
1393 {
1394         struct storvsc_device *stor_device;
1395         struct vstor_packet *vstor_packet;
1396         struct vmbus_channel *outgoing_channel;
1397         int ret = 0;
1398
1399         vstor_packet = &request->vstor_packet;
1400         stor_device = get_out_stor_device(device);
1401
1402         if (!stor_device)
1403                 return -ENODEV;
1404
1405
1406         request->device  = device;
1407         /*
1408          * Select an an appropriate channel to send the request out.
1409          */
1410
1411         outgoing_channel = vmbus_get_outgoing_channel(device->channel);
1412
1413
1414         vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1415
1416         vstor_packet->vm_srb.length = (sizeof(struct vmscsi_request) -
1417                                         vmscsi_size_delta);
1418
1419
1420         vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1421
1422
1423         vstor_packet->vm_srb.data_transfer_length =
1424         request->payload->range.len;
1425
1426         vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1427
1428         if (request->payload->range.len) {
1429
1430                 ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
1431                                 request->payload, request->payload_sz,
1432                                 vstor_packet,
1433                                 (sizeof(struct vstor_packet) -
1434                                 vmscsi_size_delta),
1435                                 (unsigned long)request);
1436         } else {
1437                 ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
1438                                (sizeof(struct vstor_packet) -
1439                                 vmscsi_size_delta),
1440                                (unsigned long)request,
1441                                VM_PKT_DATA_INBAND,
1442                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1443         }
1444
1445         if (ret != 0)
1446                 return ret;
1447
1448         atomic_inc(&stor_device->num_outstanding_req);
1449
1450         return ret;
1451 }
1452
1453 static int storvsc_device_configure(struct scsi_device *sdevice)
1454 {
1455
1456         blk_queue_max_segment_size(sdevice->request_queue, PAGE_SIZE);
1457
1458         blk_queue_bounce_limit(sdevice->request_queue, BLK_BOUNCE_ANY);
1459
1460         blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1461
1462         sdevice->no_write_same = 1;
1463
1464         /*
1465          * Add blist flags to permit the reading of the VPD pages even when
1466          * the target may claim SPC-2 compliance. MSFT targets currently
1467          * claim SPC-2 compliance while they implement post SPC-2 features.
1468          * With this patch we can correctly handle WRITE_SAME_16 issues.
1469          */
1470         sdevice->sdev_bflags |= msft_blist_flags;
1471
1472         /*
1473          * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
1474          * if the device is a MSFT virtual device.
1475          */
1476         if (!strncmp(sdevice->vendor, "Msft", 4)) {
1477                 switch (vmbus_proto_version) {
1478                 case VERSION_WIN8:
1479                 case VERSION_WIN8_1:
1480                         sdevice->scsi_level = SCSI_SPC_3;
1481                         break;
1482                 }
1483         }
1484
1485         return 0;
1486 }
1487
1488 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1489                            sector_t capacity, int *info)
1490 {
1491         sector_t nsect = capacity;
1492         sector_t cylinders = nsect;
1493         int heads, sectors_pt;
1494
1495         /*
1496          * We are making up these values; let us keep it simple.
1497          */
1498         heads = 0xff;
1499         sectors_pt = 0x3f;      /* Sectors per track */
1500         sector_div(cylinders, heads * sectors_pt);
1501         if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1502                 cylinders = 0xffff;
1503
1504         info[0] = heads;
1505         info[1] = sectors_pt;
1506         info[2] = (int)cylinders;
1507
1508         return 0;
1509 }
1510
1511 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1512 {
1513         struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1514         struct hv_device *device = host_dev->dev;
1515
1516         struct storvsc_device *stor_device;
1517         struct storvsc_cmd_request *request;
1518         struct vstor_packet *vstor_packet;
1519         int ret, t;
1520
1521
1522         stor_device = get_out_stor_device(device);
1523         if (!stor_device)
1524                 return FAILED;
1525
1526         request = &stor_device->reset_request;
1527         vstor_packet = &request->vstor_packet;
1528
1529         init_completion(&request->wait_event);
1530
1531         vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1532         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1533         vstor_packet->vm_srb.path_id = stor_device->path_id;
1534
1535         ret = vmbus_sendpacket(device->channel, vstor_packet,
1536                                (sizeof(struct vstor_packet) -
1537                                 vmscsi_size_delta),
1538                                (unsigned long)&stor_device->reset_request,
1539                                VM_PKT_DATA_INBAND,
1540                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1541         if (ret != 0)
1542                 return FAILED;
1543
1544         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1545         if (t == 0)
1546                 return TIMEOUT_ERROR;
1547
1548
1549         /*
1550          * At this point, all outstanding requests in the adapter
1551          * should have been flushed out and return to us
1552          * There is a potential race here where the host may be in
1553          * the process of responding when we return from here.
1554          * Just wait for all in-transit packets to be accounted for
1555          * before we return from here.
1556          */
1557         storvsc_wait_to_drain(stor_device);
1558
1559         return SUCCESS;
1560 }
1561
1562 /*
1563  * The host guarantees to respond to each command, although I/O latencies might
1564  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1565  * chance to perform EH.
1566  */
1567 static enum blk_eh_timer_return storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1568 {
1569         return BLK_EH_RESET_TIMER;
1570 }
1571
1572 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1573 {
1574         bool allowed = true;
1575         u8 scsi_op = scmnd->cmnd[0];
1576
1577         switch (scsi_op) {
1578         /* the host does not handle WRITE_SAME, log accident usage */
1579         case WRITE_SAME:
1580         /*
1581          * smartd sends this command and the host does not handle
1582          * this. So, don't send it.
1583          */
1584         case SET_WINDOW:
1585                 scmnd->result = ILLEGAL_REQUEST << 16;
1586                 allowed = false;
1587                 break;
1588         default:
1589                 break;
1590         }
1591         return allowed;
1592 }
1593
1594 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1595 {
1596         int ret;
1597         struct hv_host_device *host_dev = shost_priv(host);
1598         struct hv_device *dev = host_dev->dev;
1599         struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
1600         int i;
1601         struct scatterlist *sgl;
1602         unsigned int sg_count = 0;
1603         struct vmscsi_request *vm_srb;
1604         struct scatterlist *cur_sgl;
1605         struct vmbus_packet_mpb_array  *payload;
1606         u32 payload_sz;
1607         u32 length;
1608
1609         if (vmstor_proto_version <= VMSTOR_PROTO_VERSION_WIN8) {
1610                 /*
1611                  * On legacy hosts filter unimplemented commands.
1612                  * Future hosts are expected to correctly handle
1613                  * unsupported commands. Furthermore, it is
1614                  * possible that some of the currently
1615                  * unsupported commands maybe supported in
1616                  * future versions of the host.
1617                  */
1618                 if (!storvsc_scsi_cmd_ok(scmnd)) {
1619                         scmnd->scsi_done(scmnd);
1620                         return 0;
1621                 }
1622         }
1623
1624         /* Setup the cmd request */
1625         cmd_request->cmd = scmnd;
1626
1627         vm_srb = &cmd_request->vstor_packet.vm_srb;
1628         vm_srb->win8_extension.time_out_value = 60;
1629
1630         vm_srb->win8_extension.srb_flags |=
1631                 (SRB_FLAGS_QUEUE_ACTION_ENABLE |
1632                 SRB_FLAGS_DISABLE_SYNCH_TRANSFER);
1633
1634         /* Build the SRB */
1635         switch (scmnd->sc_data_direction) {
1636         case DMA_TO_DEVICE:
1637                 vm_srb->data_in = WRITE_TYPE;
1638                 vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_OUT;
1639                 break;
1640         case DMA_FROM_DEVICE:
1641                 vm_srb->data_in = READ_TYPE;
1642                 vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_IN;
1643                 break;
1644         case DMA_NONE:
1645                 vm_srb->data_in = UNKNOWN_TYPE;
1646                 vm_srb->win8_extension.srb_flags |= SRB_FLAGS_NO_DATA_TRANSFER;
1647                 break;
1648         default:
1649                 /*
1650                  * This is DMA_BIDIRECTIONAL or something else we are never
1651                  * supposed to see here.
1652                  */
1653                 WARN(1, "Unexpected data direction: %d\n",
1654                      scmnd->sc_data_direction);
1655                 return -EINVAL;
1656         }
1657
1658
1659         vm_srb->port_number = host_dev->port;
1660         vm_srb->path_id = scmnd->device->channel;
1661         vm_srb->target_id = scmnd->device->id;
1662         vm_srb->lun = scmnd->device->lun;
1663
1664         vm_srb->cdb_length = scmnd->cmd_len;
1665
1666         memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1667
1668         sgl = (struct scatterlist *)scsi_sglist(scmnd);
1669         sg_count = scsi_sg_count(scmnd);
1670
1671         length = scsi_bufflen(scmnd);
1672         payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
1673         payload_sz = sizeof(cmd_request->mpb);
1674
1675         if (sg_count) {
1676                 /* check if we need to bounce the sgl */
1677                 if (do_bounce_buffer(sgl, scsi_sg_count(scmnd)) != -1) {
1678                         cmd_request->bounce_sgl =
1679                                 create_bounce_buffer(sgl, sg_count,
1680                                                      length,
1681                                                      vm_srb->data_in);
1682                         if (!cmd_request->bounce_sgl)
1683                                 return SCSI_MLQUEUE_HOST_BUSY;
1684
1685                         cmd_request->bounce_sgl_count =
1686                                 ALIGN(length, PAGE_SIZE) >> PAGE_SHIFT;
1687
1688                         if (vm_srb->data_in == WRITE_TYPE)
1689                                 copy_to_bounce_buffer(sgl,
1690                                         cmd_request->bounce_sgl, sg_count);
1691
1692                         sgl = cmd_request->bounce_sgl;
1693                         sg_count = cmd_request->bounce_sgl_count;
1694                 }
1695
1696
1697                 if (sg_count > MAX_PAGE_BUFFER_COUNT) {
1698
1699                         payload_sz = (sg_count * sizeof(void *) +
1700                                       sizeof(struct vmbus_packet_mpb_array));
1701                         payload = kmalloc(payload_sz, GFP_ATOMIC);
1702                         if (!payload) {
1703                                 if (cmd_request->bounce_sgl_count)
1704                                         destroy_bounce_buffer(
1705                                         cmd_request->bounce_sgl,
1706                                         cmd_request->bounce_sgl_count);
1707
1708                                         return SCSI_MLQUEUE_DEVICE_BUSY;
1709                         }
1710                 }
1711
1712                 payload->range.len = length;
1713                 payload->range.offset = sgl[0].offset;
1714
1715                 cur_sgl = sgl;
1716                 for (i = 0; i < sg_count; i++) {
1717                         payload->range.pfn_array[i] =
1718                                 page_to_pfn(sg_page((cur_sgl)));
1719                         cur_sgl = sg_next(cur_sgl);
1720                 }
1721
1722         } else if (scsi_sglist(scmnd)) {
1723                 payload->range.len = length;
1724                 payload->range.offset =
1725                         virt_to_phys(scsi_sglist(scmnd)) & (PAGE_SIZE-1);
1726                 payload->range.pfn_array[0] =
1727                         virt_to_phys(scsi_sglist(scmnd)) >> PAGE_SHIFT;
1728         }
1729
1730         cmd_request->payload = payload;
1731         cmd_request->payload_sz = payload_sz;
1732
1733         /* Invokes the vsc to start an IO */
1734         ret = storvsc_do_io(dev, cmd_request);
1735
1736         if (ret == -EAGAIN) {
1737                 /* no more space */
1738
1739                 if (cmd_request->bounce_sgl_count)
1740                         destroy_bounce_buffer(cmd_request->bounce_sgl,
1741                                         cmd_request->bounce_sgl_count);
1742
1743                 return SCSI_MLQUEUE_DEVICE_BUSY;
1744         }
1745
1746         return 0;
1747 }
1748
1749 static struct scsi_host_template scsi_driver = {
1750         .module =               THIS_MODULE,
1751         .name =                 "storvsc_host_t",
1752         .cmd_size =             sizeof(struct storvsc_cmd_request),
1753         .bios_param =           storvsc_get_chs,
1754         .queuecommand =         storvsc_queuecommand,
1755         .eh_host_reset_handler =        storvsc_host_reset_handler,
1756         .proc_name =            "storvsc_host",
1757         .eh_timed_out =         storvsc_eh_timed_out,
1758         .slave_configure =      storvsc_device_configure,
1759         .cmd_per_lun =          255,
1760         .this_id =              -1,
1761         .use_clustering =       ENABLE_CLUSTERING,
1762         /* Make sure we dont get a sg segment crosses a page boundary */
1763         .dma_boundary =         PAGE_SIZE-1,
1764         .no_write_same =        1,
1765 };
1766
1767 enum {
1768         SCSI_GUID,
1769         IDE_GUID,
1770         SFC_GUID,
1771 };
1772
1773 static const struct hv_vmbus_device_id id_table[] = {
1774         /* SCSI guid */
1775         { HV_SCSI_GUID,
1776           .driver_data = SCSI_GUID
1777         },
1778         /* IDE guid */
1779         { HV_IDE_GUID,
1780           .driver_data = IDE_GUID
1781         },
1782         /* Fibre Channel GUID */
1783         {
1784           HV_SYNTHFC_GUID,
1785           .driver_data = SFC_GUID
1786         },
1787         { },
1788 };
1789
1790 MODULE_DEVICE_TABLE(vmbus, id_table);
1791
1792 static int storvsc_probe(struct hv_device *device,
1793                         const struct hv_vmbus_device_id *dev_id)
1794 {
1795         int ret;
1796         int num_cpus = num_online_cpus();
1797         struct Scsi_Host *host;
1798         struct hv_host_device *host_dev;
1799         bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1800         int target = 0;
1801         struct storvsc_device *stor_device;
1802         int max_luns_per_target;
1803         int max_targets;
1804         int max_channels;
1805         int max_sub_channels = 0;
1806
1807         /*
1808          * Based on the windows host we are running on,
1809          * set state to properly communicate with the host.
1810          */
1811
1812         if (vmbus_proto_version < VERSION_WIN8) {
1813                 sense_buffer_size = PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE;
1814                 vmscsi_size_delta = sizeof(struct vmscsi_win8_extension);
1815                 max_luns_per_target = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1816                 max_targets = STORVSC_IDE_MAX_TARGETS;
1817                 max_channels = STORVSC_IDE_MAX_CHANNELS;
1818         } else {
1819                 sense_buffer_size = POST_WIN7_STORVSC_SENSE_BUFFER_SIZE;
1820                 vmscsi_size_delta = 0;
1821                 max_luns_per_target = STORVSC_MAX_LUNS_PER_TARGET;
1822                 max_targets = STORVSC_MAX_TARGETS;
1823                 max_channels = STORVSC_MAX_CHANNELS;
1824                 /*
1825                  * On Windows8 and above, we support sub-channels for storage.
1826                  * The number of sub-channels offerred is based on the number of
1827                  * VCPUs in the guest.
1828                  */
1829                 max_sub_channels = (num_cpus / storvsc_vcpus_per_sub_channel);
1830         }
1831
1832         scsi_driver.can_queue = (max_outstanding_req_per_channel *
1833                                  (max_sub_channels + 1));
1834
1835         host = scsi_host_alloc(&scsi_driver,
1836                                sizeof(struct hv_host_device));
1837         if (!host)
1838                 return -ENOMEM;
1839
1840         host_dev = shost_priv(host);
1841         memset(host_dev, 0, sizeof(struct hv_host_device));
1842
1843         host_dev->port = host->host_no;
1844         host_dev->dev = device;
1845
1846
1847         stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1848         if (!stor_device) {
1849                 ret = -ENOMEM;
1850                 goto err_out0;
1851         }
1852
1853         stor_device->destroy = false;
1854         stor_device->open_sub_channel = false;
1855         init_waitqueue_head(&stor_device->waiting_to_drain);
1856         stor_device->device = device;
1857         stor_device->host = host;
1858         hv_set_drvdata(device, stor_device);
1859
1860         stor_device->port_number = host->host_no;
1861         ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size);
1862         if (ret)
1863                 goto err_out1;
1864
1865         host_dev->path = stor_device->path_id;
1866         host_dev->target = stor_device->target_id;
1867
1868         switch (dev_id->driver_data) {
1869         case SFC_GUID:
1870                 host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
1871                 host->max_id = STORVSC_FC_MAX_TARGETS;
1872                 host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
1873                 break;
1874
1875         case SCSI_GUID:
1876                 host->max_lun = max_luns_per_target;
1877                 host->max_id = max_targets;
1878                 host->max_channel = max_channels - 1;
1879                 break;
1880
1881         default:
1882                 host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1883                 host->max_id = STORVSC_IDE_MAX_TARGETS;
1884                 host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
1885                 break;
1886         }
1887         /* max cmd length */
1888         host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1889
1890         /*
1891          * set the table size based on the info we got
1892          * from the host.
1893          */
1894         host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT);
1895
1896         /* Register the HBA and start the scsi bus scan */
1897         ret = scsi_add_host(host, &device->device);
1898         if (ret != 0)
1899                 goto err_out2;
1900
1901         if (!dev_is_ide) {
1902                 scsi_scan_host(host);
1903         } else {
1904                 target = (device->dev_instance.b[5] << 8 |
1905                          device->dev_instance.b[4]);
1906                 ret = scsi_add_device(host, 0, target, 0);
1907                 if (ret) {
1908                         scsi_remove_host(host);
1909                         goto err_out2;
1910                 }
1911         }
1912         return 0;
1913
1914 err_out2:
1915         /*
1916          * Once we have connected with the host, we would need to
1917          * to invoke storvsc_dev_remove() to rollback this state and
1918          * this call also frees up the stor_device; hence the jump around
1919          * err_out1 label.
1920          */
1921         storvsc_dev_remove(device);
1922         goto err_out0;
1923
1924 err_out1:
1925         kfree(stor_device);
1926
1927 err_out0:
1928         scsi_host_put(host);
1929         return ret;
1930 }
1931
1932 static int storvsc_remove(struct hv_device *dev)
1933 {
1934         struct storvsc_device *stor_device = hv_get_drvdata(dev);
1935         struct Scsi_Host *host = stor_device->host;
1936
1937         scsi_remove_host(host);
1938         storvsc_dev_remove(dev);
1939         scsi_host_put(host);
1940
1941         return 0;
1942 }
1943
1944 static struct hv_driver storvsc_drv = {
1945         .name = KBUILD_MODNAME,
1946         .id_table = id_table,
1947         .probe = storvsc_probe,
1948         .remove = storvsc_remove,
1949 };
1950
1951 static int __init storvsc_drv_init(void)
1952 {
1953
1954         /*
1955          * Divide the ring buffer data size (which is 1 page less
1956          * than the ring buffer size since that page is reserved for
1957          * the ring buffer indices) by the max request size (which is
1958          * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
1959          */
1960         max_outstanding_req_per_channel =
1961                 ((storvsc_ringbuffer_size - PAGE_SIZE) /
1962                 ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
1963                 sizeof(struct vstor_packet) + sizeof(u64) -
1964                 vmscsi_size_delta,
1965                 sizeof(u64)));
1966
1967         return vmbus_driver_register(&storvsc_drv);
1968 }
1969
1970 static void __exit storvsc_drv_exit(void)
1971 {
1972         vmbus_driver_unregister(&storvsc_drv);
1973 }
1974
1975 MODULE_LICENSE("GPL");
1976 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
1977 module_init(storvsc_drv_init);
1978 module_exit(storvsc_drv_exit);