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 #include <scsi/scsi_transport_fc.h>
  45 #include <scsi/scsi_transport.h>
  46
  47 /*
  48  * All wire protocol details (storage protocol between the guest and the host)
  49  * are consolidated here.
  50  *
  51  * Begin protocol definitions.
  52  */
  53
  54 /*
  55  * Version history:
  56  * V1 Beta: 0.1
  57  * V1 RC < 2008/1/31: 1.0
  58  * V1 RC > 2008/1/31:  2.0
  59  * Win7: 4.2
  60  * Win8: 5.1
  61  * Win8.1: 6.0
  62  * Win10: 6.2
  63  */
  64
  65 #define VMSTOR_PROTO_VERSION(MAJOR_, MINOR_)    ((((MAJOR_) & 0xff) << 8) | \
  66                                                 (((MINOR_) & 0xff)))
  67
  68 #define VMSTOR_PROTO_VERSION_WIN6       VMSTOR_PROTO_VERSION(2, 0)
  69 #define VMSTOR_PROTO_VERSION_WIN7       VMSTOR_PROTO_VERSION(4, 2)
  70 #define VMSTOR_PROTO_VERSION_WIN8       VMSTOR_PROTO_VERSION(5, 1)
  71 #define VMSTOR_PROTO_VERSION_WIN8_1     VMSTOR_PROTO_VERSION(6, 0)
  72 #define VMSTOR_PROTO_VERSION_WIN10      VMSTOR_PROTO_VERSION(6, 2)
  73
  74 /*  Packet structure describing virtual storage requests. */
  75 enum vstor_packet_operation {
  76         VSTOR_OPERATION_COMPLETE_IO             = 1,
  77         VSTOR_OPERATION_REMOVE_DEVICE           = 2,
  78         VSTOR_OPERATION_EXECUTE_SRB             = 3,
  79         VSTOR_OPERATION_RESET_LUN               = 4,
  80         VSTOR_OPERATION_RESET_ADAPTER           = 5,
  81         VSTOR_OPERATION_RESET_BUS               = 6,
  82         VSTOR_OPERATION_BEGIN_INITIALIZATION    = 7,
  83         VSTOR_OPERATION_END_INITIALIZATION      = 8,
  84         VSTOR_OPERATION_QUERY_PROTOCOL_VERSION  = 9,
  85         VSTOR_OPERATION_QUERY_PROPERTIES        = 10,
  86         VSTOR_OPERATION_ENUMERATE_BUS           = 11,
  87         VSTOR_OPERATION_FCHBA_DATA              = 12,
  88         VSTOR_OPERATION_CREATE_SUB_CHANNELS     = 13,
  89         VSTOR_OPERATION_MAXIMUM                 = 13
  90 };
  91
  92 /*
  93  * WWN packet for Fibre Channel HBA
  94  */
  95
  96 struct hv_fc_wwn_packet {
  97         u8      primary_active;
  98         u8      reserved1[3];
  99         u8      primary_port_wwn[8];
 100         u8      primary_node_wwn[8];
 101         u8      secondary_port_wwn[8];
 102         u8      secondary_node_wwn[8];
 103 };
 104
 105
 106
 107 /*
 108  * SRB Flag Bits
 109  */
 110
 111 #define SRB_FLAGS_QUEUE_ACTION_ENABLE           0x00000002
 112 #define SRB_FLAGS_DISABLE_DISCONNECT            0x00000004
 113 #define SRB_FLAGS_DISABLE_SYNCH_TRANSFER        0x00000008
 114 #define SRB_FLAGS_BYPASS_FROZEN_QUEUE           0x00000010
 115 #define SRB_FLAGS_DISABLE_AUTOSENSE             0x00000020
 116 #define SRB_FLAGS_DATA_IN                       0x00000040
 117 #define SRB_FLAGS_DATA_OUT                      0x00000080
 118 #define SRB_FLAGS_NO_DATA_TRANSFER              0x00000000
 119 #define SRB_FLAGS_UNSPECIFIED_DIRECTION (SRB_FLAGS_DATA_IN | SRB_FLAGS_DATA_OUT)
 120 #define SRB_FLAGS_NO_QUEUE_FREEZE               0x00000100
 121 #define SRB_FLAGS_ADAPTER_CACHE_ENABLE          0x00000200
 122 #define SRB_FLAGS_FREE_SENSE_BUFFER             0x00000400
 123
 124 /*
 125  * This flag indicates the request is part of the workflow for processing a D3.
 126  */
 127 #define SRB_FLAGS_D3_PROCESSING                 0x00000800
 128 #define SRB_FLAGS_IS_ACTIVE                     0x00010000
 129 #define SRB_FLAGS_ALLOCATED_FROM_ZONE           0x00020000
 130 #define SRB_FLAGS_SGLIST_FROM_POOL              0x00040000
 131 #define SRB_FLAGS_BYPASS_LOCKED_QUEUE           0x00080000
 132 #define SRB_FLAGS_NO_KEEP_AWAKE                 0x00100000
 133 #define SRB_FLAGS_PORT_DRIVER_ALLOCSENSE        0x00200000
 134 #define SRB_FLAGS_PORT_DRIVER_SENSEHASPORT      0x00400000
 135 #define SRB_FLAGS_DONT_START_NEXT_PACKET        0x00800000
 136 #define SRB_FLAGS_PORT_DRIVER_RESERVED          0x0F000000
 137 #define SRB_FLAGS_CLASS_DRIVER_RESERVED         0xF0000000
 138
 139 #define SP_UNTAGGED                     ((unsigned char) ~0)
 140 #define SRB_SIMPLE_TAG_REQUEST          0x20
 141
 142 /*
 143  * Platform neutral description of a scsi request -
 144  * this remains the same across the write regardless of 32/64 bit
 145  * note: it's patterned off the SCSI_PASS_THROUGH structure
 146  */
 147 #define STORVSC_MAX_CMD_LEN                     0x10
 148
 149 #define POST_WIN7_STORVSC_SENSE_BUFFER_SIZE     0x14
 150 #define PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE      0x12
 151
 152 #define STORVSC_SENSE_BUFFER_SIZE               0x14
 153 #define STORVSC_MAX_BUF_LEN_WITH_PADDING        0x14
 154
 155 /*
 156  * Sense buffer size changed in win8; have a run-time
 157  * variable to track the size we should use.  This value will
 158  * likely change during protocol negotiation but it is valid
 159  * to start by assuming pre-Win8.
 160  */
 161 static int sense_buffer_size = PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE;
 162
 163 /*
 164  * The storage protocol version is determined during the
 165  * initial exchange with the host.  It will indicate which
 166  * storage functionality is available in the host.
 167 */
 168 static int vmstor_proto_version;
 169
 170 #define STORVSC_LOGGING_NONE    0
 171 #define STORVSC_LOGGING_ERROR   1
 172 #define STORVSC_LOGGING_WARN    2
 173
 174 static int logging_level = STORVSC_LOGGING_ERROR;
 175 module_param(logging_level, int, S_IRUGO|S_IWUSR);
 176 MODULE_PARM_DESC(logging_level,
 177         "Logging level, 0 - None, 1 - Error (default), 2 - Warning.");
 178
 179 static inline bool do_logging(int level)
 180 {
 181         return logging_level >= level;
 182 }
 183
 184 #define storvsc_log(dev, level, fmt, ...)                       \
 185 do {                                                            \
 186         if (do_logging(level))                                  \
 187                 dev_warn(&(dev)->device, fmt, ##__VA_ARGS__);   \
 188 } while (0)
 189
 190 struct vmscsi_win8_extension {
 191         /*
 192          * The following were added in Windows 8
 193          */
 194         u16 reserve;
 195         u8  queue_tag;
 196         u8  queue_action;
 197         u32 srb_flags;
 198         u32 time_out_value;
 199         u32 queue_sort_ey;
 200 } __packed;
 201
 202 struct vmscsi_request {
 203         u16 length;
 204         u8 srb_status;
 205         u8 scsi_status;
 206
 207         u8  port_number;
 208         u8  path_id;
 209         u8  target_id;
 210         u8  lun;
 211
 212         u8  cdb_length;
 213         u8  sense_info_length;
 214         u8  data_in;
 215         u8  reserved;
 216
 217         u32 data_transfer_length;
 218
 219         union {
 220                 u8 cdb[STORVSC_MAX_CMD_LEN];
 221                 u8 sense_data[STORVSC_SENSE_BUFFER_SIZE];
 222                 u8 reserved_array[STORVSC_MAX_BUF_LEN_WITH_PADDING];
 223         };
 224         /*
 225          * The following was added in win8.
 226          */
 227         struct vmscsi_win8_extension win8_extension;
 228
 229 } __attribute((packed));
 230
 231
 232 /*
 233  * The size of the vmscsi_request has changed in win8. The
 234  * additional size is because of new elements added to the
 235  * structure. These elements are valid only when we are talking
 236  * to a win8 host.
 237  * Track the correction to size we need to apply. This value
 238  * will likely change during protocol negotiation but it is
 239  * valid to start by assuming pre-Win8.
 240  */
 241 static int vmscsi_size_delta = sizeof(struct vmscsi_win8_extension);
 242
 243 /*
 244  * The list of storage protocols in order of preference.
 245  */
 246 struct vmstor_protocol {
 247         int protocol_version;
 248         int sense_buffer_size;
 249         int vmscsi_size_delta;
 250 };
 251
 252
 253 static const struct vmstor_protocol vmstor_protocols[] = {
 254         {
 255                 VMSTOR_PROTO_VERSION_WIN10,
 256                 POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
 257                 0
 258         },
 259         {
 260                 VMSTOR_PROTO_VERSION_WIN8_1,
 261                 POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
 262                 0
 263         },
 264         {
 265                 VMSTOR_PROTO_VERSION_WIN8,
 266                 POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
 267                 0
 268         },
 269         {
 270                 VMSTOR_PROTO_VERSION_WIN7,
 271                 PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
 272                 sizeof(struct vmscsi_win8_extension),
 273         },
 274         {
 275                 VMSTOR_PROTO_VERSION_WIN6,
 276                 PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
 277                 sizeof(struct vmscsi_win8_extension),
 278         }
 279 };
 280
 281
 282 /*
 283  * This structure is sent during the initialization phase to get the different
 284  * properties of the channel.
 285  */
 286
 287 #define STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL          0x1
 288
 289 struct vmstorage_channel_properties {
 290         u32 reserved;
 291         u16 max_channel_cnt;
 292         u16 reserved1;
 293
 294         u32 flags;
 295         u32   max_transfer_bytes;
 296
 297         u64  reserved2;
 298 } __packed;
 299
 300 /*  This structure is sent during the storage protocol negotiations. */
 301 struct vmstorage_protocol_version {
 302         /* Major (MSW) and minor (LSW) version numbers. */
 303         u16 major_minor;
 304
 305         /*
 306          * Revision number is auto-incremented whenever this file is changed
 307          * (See FILL_VMSTOR_REVISION macro above).  Mismatch does not
 308          * definitely indicate incompatibility--but it does indicate mismatched
 309          * builds.
 310          * This is only used on the windows side. Just set it to 0.
 311          */
 312         u16 revision;
 313 } __packed;
 314
 315 /* Channel Property Flags */
 316 #define STORAGE_CHANNEL_REMOVABLE_FLAG          0x1
 317 #define STORAGE_CHANNEL_EMULATED_IDE_FLAG       0x2
 318
 319 struct vstor_packet {
 320         /* Requested operation type */
 321         enum vstor_packet_operation operation;
 322
 323         /*  Flags - see below for values */
 324         u32 flags;
 325
 326         /* Status of the request returned from the server side. */
 327         u32 status;
 328
 329         /* Data payload area */
 330         union {
 331                 /*
 332                  * Structure used to forward SCSI commands from the
 333                  * client to the server.
 334                  */
 335                 struct vmscsi_request vm_srb;
 336
 337                 /* Structure used to query channel properties. */
 338                 struct vmstorage_channel_properties storage_channel_properties;
 339
 340                 /* Used during version negotiations. */
 341                 struct vmstorage_protocol_version version;
 342
 343                 /* Fibre channel address packet */
 344                 struct hv_fc_wwn_packet wwn_packet;
 345
 346                 /* Number of sub-channels to create */
 347                 u16 sub_channel_count;
 348
 349                 /* This will be the maximum of the union members */
 350                 u8  buffer[0x34];
 351         };
 352 } __packed;
 353
 354 /*
 355  * Packet Flags:
 356  *
 357  * This flag indicates that the server should send back a completion for this
 358  * packet.
 359  */
 360
 361 #define REQUEST_COMPLETION_FLAG 0x1
 362
 363 /* Matches Windows-end */
 364 enum storvsc_request_type {
 365         WRITE_TYPE = 0,
 366         READ_TYPE,
 367         UNKNOWN_TYPE,
 368 };
 369
 370 /*
 371  * SRB status codes and masks; a subset of the codes used here.
 372  */
 373
 374 #define SRB_STATUS_AUTOSENSE_VALID      0x80
 375 #define SRB_STATUS_QUEUE_FROZEN         0x40
 376 #define SRB_STATUS_INVALID_LUN  0x20
 377 #define SRB_STATUS_SUCCESS      0x01
 378 #define SRB_STATUS_ABORTED      0x02
 379 #define SRB_STATUS_ERROR        0x04
 380 #define SRB_STATUS_DATA_OVERRUN 0x12
 381
 382 #define SRB_STATUS(status) \
 383         (status & ~(SRB_STATUS_AUTOSENSE_VALID | SRB_STATUS_QUEUE_FROZEN))
 384 /*
 385  * This is the end of Protocol specific defines.
 386  */
 387
 388 static int storvsc_ringbuffer_size = (256 * PAGE_SIZE);
 389 static u32 max_outstanding_req_per_channel;
 390
 391 static int storvsc_vcpus_per_sub_channel = 4;
 392
 393 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
 394 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
 395
 396 module_param(storvsc_vcpus_per_sub_channel, int, S_IRUGO);
 397 MODULE_PARM_DESC(storvsc_vcpus_per_sub_channel, "Ratio of VCPUs to subchannels");
 398 /*
 399  * Timeout in seconds for all devices managed by this driver.
 400  */
 401 static int storvsc_timeout = 180;
 402
 403 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
 404 static struct scsi_transport_template *fc_transport_template;
 405 #endif
 406
 407 static void storvsc_on_channel_callback(void *context);
 408
 409 #define STORVSC_MAX_LUNS_PER_TARGET                     255
 410 #define STORVSC_MAX_TARGETS                             2
 411 #define STORVSC_MAX_CHANNELS                            8
 412
 413 #define STORVSC_FC_MAX_LUNS_PER_TARGET                  255
 414 #define STORVSC_FC_MAX_TARGETS                          128
 415 #define STORVSC_FC_MAX_CHANNELS                         8
 416
 417 #define STORVSC_IDE_MAX_LUNS_PER_TARGET                 64
 418 #define STORVSC_IDE_MAX_TARGETS                         1
 419 #define STORVSC_IDE_MAX_CHANNELS                        1
 420
 421 struct storvsc_cmd_request {
 422         struct scsi_cmnd *cmd;
 423
 424         struct hv_device *device;
 425
 426         /* Synchronize the request/response if needed */
 427         struct completion wait_event;
 428
 429         struct vmbus_channel_packet_multipage_buffer mpb;
 430         struct vmbus_packet_mpb_array *payload;
 431         u32 payload_sz;
 432
 433         struct vstor_packet vstor_packet;
 434 };
 435
 436
 437 /* A storvsc device is a device object that contains a vmbus channel */
 438 struct storvsc_device {
 439         struct hv_device *device;
 440
 441         bool     destroy;
 442         bool     drain_notify;
 443         bool     open_sub_channel;
 444         atomic_t num_outstanding_req;
 445         struct Scsi_Host *host;
 446
 447         wait_queue_head_t waiting_to_drain;
 448
 449         /*
 450          * Each unique Port/Path/Target represents 1 channel ie scsi
 451          * controller. In reality, the pathid, targetid is always 0
 452          * and the port is set by us
 453          */
 454         unsigned int port_number;
 455         unsigned char path_id;
 456         unsigned char target_id;
 457
 458         /*
 459          * Max I/O, the device can support.
 460          */
 461         u32   max_transfer_bytes;
 462         /*
 463          * Number of sub-channels we will open.
 464          */
 465         u16 num_sc;
 466         struct vmbus_channel **stor_chns;
 467         /*
 468          * Mask of CPUs bound to subchannels.
 469          */
 470         struct cpumask alloced_cpus;
 471         /* Used for vsc/vsp channel reset process */
 472         struct storvsc_cmd_request init_request;
 473         struct storvsc_cmd_request reset_request;
 474         /*
 475          * Currently active port and node names for FC devices.
 476          */
 477         u64 node_name;
 478         u64 port_name;
 479 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
 480         struct fc_rport *rport;
 481 #endif
 482 };
 483
 484 struct hv_host_device {
 485         struct hv_device *dev;
 486         unsigned int port;
 487         unsigned char path;
 488         unsigned char target;
 489         struct workqueue_struct *handle_error_wq;
 490         struct work_struct host_scan_work;
 491         struct Scsi_Host *host;
 492 };
 493
 494 struct storvsc_scan_work {
 495         struct work_struct work;
 496         struct Scsi_Host *host;
 497         u8 lun;
 498         u8 tgt_id;
 499 };
 500
 501 static void storvsc_device_scan(struct work_struct *work)
 502 {
 503         struct storvsc_scan_work *wrk;
 504         struct scsi_device *sdev;
 505
 506         wrk = container_of(work, struct storvsc_scan_work, work);
 507
 508         sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
 509         if (!sdev)
 510                 goto done;
 511         scsi_rescan_device(&sdev->sdev_gendev);
 512         scsi_device_put(sdev);
 513
 514 done:
 515         kfree(wrk);
 516 }
 517
 518 static void storvsc_host_scan(struct work_struct *work)
 519 {
 520         struct Scsi_Host *host;
 521         struct scsi_device *sdev;
 522         struct hv_host_device *host_device =
 523                 container_of(work, struct hv_host_device, host_scan_work);
 524
 525         host = host_device->host;
 526         /*
 527          * Before scanning the host, first check to see if any of the
 528          * currrently known devices have been hot removed. We issue a
 529          * "unit ready" command against all currently known devices.
 530          * This I/O will result in an error for devices that have been
 531          * removed. As part of handling the I/O error, we remove the device.
 532          *
 533          * When a LUN is added or removed, the host sends us a signal to
 534          * scan the host. Thus we are forced to discover the LUNs that
 535          * may have been removed this way.
 536          */
 537         mutex_lock(&host->scan_mutex);
 538         shost_for_each_device(sdev, host)
 539                 scsi_test_unit_ready(sdev, 1, 1, NULL);
 540         mutex_unlock(&host->scan_mutex);
 541         /*
 542          * Now scan the host to discover LUNs that may have been added.
 543          */
 544         scsi_scan_host(host);
 545 }
 546
 547 static void storvsc_remove_lun(struct work_struct *work)
 548 {
 549         struct storvsc_scan_work *wrk;
 550         struct scsi_device *sdev;
 551
 552         wrk = container_of(work, struct storvsc_scan_work, work);
 553         if (!scsi_host_get(wrk->host))
 554                 goto done;
 555
 556         sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
 557
 558         if (sdev) {
 559                 scsi_remove_device(sdev);
 560                 scsi_device_put(sdev);
 561         }
 562         scsi_host_put(wrk->host);
 563
 564 done:
 565         kfree(wrk);
 566 }
 567
 568
 569 /*
 570  * We can get incoming messages from the host that are not in response to
 571  * messages that we have sent out. An example of this would be messages
 572  * received by the guest to notify dynamic addition/removal of LUNs. To
 573  * deal with potential race conditions where the driver may be in the
 574  * midst of being unloaded when we might receive an unsolicited message
 575  * from the host, we have implemented a mechanism to gurantee sequential
 576  * consistency:
 577  *
 578  * 1) Once the device is marked as being destroyed, we will fail all
 579  *    outgoing messages.
 580  * 2) We permit incoming messages when the device is being destroyed,
 581  *    only to properly account for messages already sent out.
 582  */
 583
 584 static inline struct storvsc_device *get_out_stor_device(
 585                                         struct hv_device *device)
 586 {
 587         struct storvsc_device *stor_device;
 588
 589         stor_device = hv_get_drvdata(device);
 590
 591         if (stor_device && stor_device->destroy)
 592                 stor_device = NULL;
 593
 594         return stor_device;
 595 }
 596
 597
 598 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
 599 {
 600         dev->drain_notify = true;
 601         wait_event(dev->waiting_to_drain,
 602                    atomic_read(&dev->num_outstanding_req) == 0);
 603         dev->drain_notify = false;
 604 }
 605
 606 static inline struct storvsc_device *get_in_stor_device(
 607                                         struct hv_device *device)
 608 {
 609         struct storvsc_device *stor_device;
 610
 611         stor_device = hv_get_drvdata(device);
 612
 613         if (!stor_device)
 614                 goto get_in_err;
 615
 616         /*
 617          * If the device is being destroyed; allow incoming
 618          * traffic only to cleanup outstanding requests.
 619          */
 620
 621         if (stor_device->destroy  &&
 622                 (atomic_read(&stor_device->num_outstanding_req) == 0))
 623                 stor_device = NULL;
 624
 625 get_in_err:
 626         return stor_device;
 627
 628 }
 629
 630 static void handle_sc_creation(struct vmbus_channel *new_sc)
 631 {
 632         struct hv_device *device = new_sc->primary_channel->device_obj;
 633         struct storvsc_device *stor_device;
 634         struct vmstorage_channel_properties props;
 635
 636         stor_device = get_out_stor_device(device);
 637         if (!stor_device)
 638                 return;
 639
 640         if (stor_device->open_sub_channel == false)
 641                 return;
 642
 643         memset(&props, 0, sizeof(struct vmstorage_channel_properties));
 644
 645         vmbus_open(new_sc,
 646                    storvsc_ringbuffer_size,
 647                    storvsc_ringbuffer_size,
 648                    (void *)&props,
 649                    sizeof(struct vmstorage_channel_properties),
 650                    storvsc_on_channel_callback, new_sc);
 651
 652         if (new_sc->state == CHANNEL_OPENED_STATE) {
 653                 stor_device->stor_chns[new_sc->target_cpu] = new_sc;
 654                 cpumask_set_cpu(new_sc->target_cpu, &stor_device->alloced_cpus);
 655         }
 656 }
 657
 658 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
 659 {
 660         struct storvsc_device *stor_device;
 661         int num_cpus = num_online_cpus();
 662         int num_sc;
 663         struct storvsc_cmd_request *request;
 664         struct vstor_packet *vstor_packet;
 665         int ret, t;
 666
 667         num_sc = ((max_chns > num_cpus) ? num_cpus : max_chns);
 668         stor_device = get_out_stor_device(device);
 669         if (!stor_device)
 670                 return;
 671
 672         stor_device->num_sc = num_sc;
 673         request = &stor_device->init_request;
 674         vstor_packet = &request->vstor_packet;
 675
 676         stor_device->open_sub_channel = true;
 677         /*
 678          * Establish a handler for dealing with subchannels.
 679          */
 680         vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
 681
 682         /*
 683          * Check to see if sub-channels have already been created. This
 684          * can happen when this driver is re-loaded after unloading.
 685          */
 686
 687         if (vmbus_are_subchannels_present(device->channel))
 688                 return;
 689
 690         stor_device->open_sub_channel = false;
 691         /*
 692          * Request the host to create sub-channels.
 693          */
 694         memset(request, 0, sizeof(struct storvsc_cmd_request));
 695         init_completion(&request->wait_event);
 696         vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
 697         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 698         vstor_packet->sub_channel_count = num_sc;
 699
 700         ret = vmbus_sendpacket(device->channel, vstor_packet,
 701                                (sizeof(struct vstor_packet) -
 702                                vmscsi_size_delta),
 703                                (unsigned long)request,
 704                                VM_PKT_DATA_INBAND,
 705                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 706
 707         if (ret != 0)
 708                 return;
 709
 710         t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
 711         if (t == 0)
 712                 return;
 713
 714         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
 715             vstor_packet->status != 0)
 716                 return;
 717
 718         /*
 719          * Now that we created the sub-channels, invoke the check; this
 720          * may trigger the callback.
 721          */
 722         stor_device->open_sub_channel = true;
 723         vmbus_are_subchannels_present(device->channel);
 724 }
 725
 726 static void cache_wwn(struct storvsc_device *stor_device,
 727                       struct vstor_packet *vstor_packet)
 728 {
 729         /*
 730          * Cache the currently active port and node ww names.
 731          */
 732         if (vstor_packet->wwn_packet.primary_active) {
 733                 stor_device->node_name =
 734                         wwn_to_u64(vstor_packet->wwn_packet.primary_node_wwn);
 735                 stor_device->port_name =
 736                         wwn_to_u64(vstor_packet->wwn_packet.primary_port_wwn);
 737         } else {
 738                 stor_device->node_name =
 739                         wwn_to_u64(vstor_packet->wwn_packet.secondary_node_wwn);
 740                 stor_device->port_name =
 741                         wwn_to_u64(vstor_packet->wwn_packet.secondary_port_wwn);
 742         }
 743 }
 744
 745
 746 static int storvsc_execute_vstor_op(struct hv_device *device,
 747                                     struct storvsc_cmd_request *request,
 748                                     bool status_check)
 749 {
 750         struct vstor_packet *vstor_packet;
 751         int ret, t;
 752
 753         vstor_packet = &request->vstor_packet;
 754
 755         init_completion(&request->wait_event);
 756         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 757
 758         ret = vmbus_sendpacket(device->channel, vstor_packet,
 759                                (sizeof(struct vstor_packet) -
 760                                vmscsi_size_delta),
 761                                (unsigned long)request,
 762                                VM_PKT_DATA_INBAND,
 763                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 764         if (ret != 0)
 765                 return ret;
 766
 767         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
 768         if (t == 0)
 769                 return -ETIMEDOUT;
 770
 771         if (!status_check)
 772                 return ret;
 773
 774         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
 775             vstor_packet->status != 0)
 776                 return -EINVAL;
 777
 778         return ret;
 779 }
 780
 781 static int storvsc_channel_init(struct hv_device *device, bool is_fc)
 782 {
 783         struct storvsc_device *stor_device;
 784         struct storvsc_cmd_request *request;
 785         struct vstor_packet *vstor_packet;
 786         int ret, i;
 787         int max_chns;
 788         bool process_sub_channels = false;
 789
 790         stor_device = get_out_stor_device(device);
 791         if (!stor_device)
 792                 return -ENODEV;
 793
 794         request = &stor_device->init_request;
 795         vstor_packet = &request->vstor_packet;
 796
 797         /*
 798          * Now, initiate the vsc/vsp initialization protocol on the open
 799          * channel
 800          */
 801         memset(request, 0, sizeof(struct storvsc_cmd_request));
 802         vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
 803         ret = storvsc_execute_vstor_op(device, request, true);
 804         if (ret)
 805                 return ret;
 806         /*
 807          * Query host supported protocol version.
 808          */
 809
 810         for (i = 0; i < ARRAY_SIZE(vmstor_protocols); i++) {
 811                 /* reuse the packet for version range supported */
 812                 memset(vstor_packet, 0, sizeof(struct vstor_packet));
 813                 vstor_packet->operation =
 814                         VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
 815
 816                 vstor_packet->version.major_minor =
 817                         vmstor_protocols[i].protocol_version;
 818
 819                 /*
 820                  * The revision number is only used in Windows; set it to 0.
 821                  */
 822                 vstor_packet->version.revision = 0;
 823                 ret = storvsc_execute_vstor_op(device, request, false);
 824                 if (ret != 0)
 825                         return ret;
 826
 827                 if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO)
 828                         return -EINVAL;
 829
 830                 if (vstor_packet->status == 0) {
 831                         vmstor_proto_version =
 832                                 vmstor_protocols[i].protocol_version;
 833
 834                         sense_buffer_size =
 835                                 vmstor_protocols[i].sense_buffer_size;
 836
 837                         vmscsi_size_delta =
 838                                 vmstor_protocols[i].vmscsi_size_delta;
 839
 840                         break;
 841                 }
 842         }
 843
 844         if (vstor_packet->status != 0)
 845                 return -EINVAL;
 846
 847
 848         memset(vstor_packet, 0, sizeof(struct vstor_packet));
 849         vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
 850         ret = storvsc_execute_vstor_op(device, request, true);
 851         if (ret != 0)
 852                 return ret;
 853
 854         /*
 855          * Check to see if multi-channel support is there.
 856          * Hosts that implement protocol version of 5.1 and above
 857          * support multi-channel.
 858          */
 859         max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
 860
 861         /*
 862          * Allocate state to manage the sub-channels.
 863          * We allocate an array based on the numbers of possible CPUs
 864          * (Hyper-V does not support cpu online/offline).
 865          * This Array will be sparseley populated with unique
 866          * channels - primary + sub-channels.
 867          * We will however populate all the slots to evenly distribute
 868          * the load.
 869          */
 870         stor_device->stor_chns = kcalloc(num_possible_cpus(), sizeof(void *),
 871                                          GFP_KERNEL);
 872         if (stor_device->stor_chns == NULL)
 873                 return -ENOMEM;
 874
 875         stor_device->stor_chns[device->channel->target_cpu] = device->channel;
 876         cpumask_set_cpu(device->channel->target_cpu,
 877                         &stor_device->alloced_cpus);
 878
 879         if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN8) {
 880                 if (vstor_packet->storage_channel_properties.flags &
 881                     STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
 882                         process_sub_channels = true;
 883         }
 884         stor_device->max_transfer_bytes =
 885                 vstor_packet->storage_channel_properties.max_transfer_bytes;
 886
 887         if (!is_fc)
 888                 goto done;
 889
 890         /*
 891          * For FC devices retrieve FC HBA data.
 892          */
 893         memset(vstor_packet, 0, sizeof(struct vstor_packet));
 894         vstor_packet->operation = VSTOR_OPERATION_FCHBA_DATA;
 895         ret = storvsc_execute_vstor_op(device, request, true);
 896         if (ret != 0)
 897                 return ret;
 898
 899         /*
 900          * Cache the currently active port and node ww names.
 901          */
 902         cache_wwn(stor_device, vstor_packet);
 903
 904 done:
 905
 906         memset(vstor_packet, 0, sizeof(struct vstor_packet));
 907         vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
 908         ret = storvsc_execute_vstor_op(device, request, true);
 909         if (ret != 0)
 910                 return ret;
 911
 912         if (process_sub_channels)
 913                 handle_multichannel_storage(device, max_chns);
 914
 915         return ret;
 916 }
 917
 918 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
 919                                 struct scsi_cmnd *scmnd,
 920                                 struct Scsi_Host *host,
 921                                 u8 asc, u8 ascq)
 922 {
 923         struct storvsc_scan_work *wrk;
 924         void (*process_err_fn)(struct work_struct *work);
 925         struct hv_host_device *host_dev = shost_priv(host);
 926         bool do_work = false;
 927
 928         switch (SRB_STATUS(vm_srb->srb_status)) {
 929         case SRB_STATUS_ERROR:
 930                 /*
 931                  * Let upper layer deal with error when
 932                  * sense message is present.
 933                  */
 934
 935                 if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID)
 936                         break;
 937                 /*
 938                  * If there is an error; offline the device since all
 939                  * error recovery strategies would have already been
 940                  * deployed on the host side. However, if the command
 941                  * were a pass-through command deal with it appropriately.
 942                  */
 943                 switch (scmnd->cmnd[0]) {
 944                 case ATA_16:
 945                 case ATA_12:
 946                         set_host_byte(scmnd, DID_PASSTHROUGH);
 947                         break;
 948                 /*
 949                  * On Some Windows hosts TEST_UNIT_READY command can return
 950                  * SRB_STATUS_ERROR, let the upper level code deal with it
 951                  * based on the sense information.
 952                  */
 953                 case TEST_UNIT_READY:
 954                         break;
 955                 default:
 956                         set_host_byte(scmnd, DID_TARGET_FAILURE);
 957                 }
 958                 break;
 959         case SRB_STATUS_INVALID_LUN:
 960                 do_work = true;
 961                 process_err_fn = storvsc_remove_lun;
 962                 break;
 963         case SRB_STATUS_ABORTED:
 964                 if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID &&
 965                     (asc == 0x2a) && (ascq == 0x9)) {
 966                         do_work = true;
 967                         process_err_fn = storvsc_device_scan;
 968                         /*
 969                          * Retry the I/O that trigerred this.
 970                          */
 971                         set_host_byte(scmnd, DID_REQUEUE);
 972                 }
 973                 break;
 974         }
 975
 976         if (!do_work)
 977                 return;
 978
 979         /*
 980          * We need to schedule work to process this error; schedule it.
 981          */
 982         wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
 983         if (!wrk) {
 984                 set_host_byte(scmnd, DID_TARGET_FAILURE);
 985                 return;
 986         }
 987
 988         wrk->host = host;
 989         wrk->lun = vm_srb->lun;
 990         wrk->tgt_id = vm_srb->target_id;
 991         INIT_WORK(&wrk->work, process_err_fn);
 992         queue_work(host_dev->handle_error_wq, &wrk->work);
 993 }
 994
 995
 996 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request,
 997                                        struct storvsc_device *stor_dev)
 998 {
 999         struct scsi_cmnd *scmnd = cmd_request->cmd;
1000         struct scsi_sense_hdr sense_hdr;
1001         struct vmscsi_request *vm_srb;
1002         u32 data_transfer_length;
1003         struct Scsi_Host *host;
1004         u32 payload_sz = cmd_request->payload_sz;
1005         void *payload = cmd_request->payload;
1006
1007         host = stor_dev->host;
1008
1009         vm_srb = &cmd_request->vstor_packet.vm_srb;
1010         data_transfer_length = vm_srb->data_transfer_length;
1011
1012         scmnd->result = vm_srb->scsi_status;
1013
1014         if (scmnd->result) {
1015                 if (scsi_normalize_sense(scmnd->sense_buffer,
1016                                 SCSI_SENSE_BUFFERSIZE, &sense_hdr) &&
1017                     !(sense_hdr.sense_key == NOT_READY &&
1018                                  sense_hdr.asc == 0x03A) &&
1019                     do_logging(STORVSC_LOGGING_ERROR))
1020                         scsi_print_sense_hdr(scmnd->device, "storvsc",
1021                                              &sense_hdr);
1022         }
1023
1024         if (vm_srb->srb_status != SRB_STATUS_SUCCESS) {
1025                 storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
1026                                          sense_hdr.ascq);
1027                 /*
1028                  * The Windows driver set data_transfer_length on
1029                  * SRB_STATUS_DATA_OVERRUN. On other errors, this value
1030                  * is untouched.  In these cases we set it to 0.
1031                  */
1032                 if (vm_srb->srb_status != SRB_STATUS_DATA_OVERRUN)
1033                         data_transfer_length = 0;
1034         }
1035
1036         scsi_set_resid(scmnd,
1037                 cmd_request->payload->range.len - data_transfer_length);
1038
1039         scmnd->scsi_done(scmnd);
1040
1041         if (payload_sz >
1042                 sizeof(struct vmbus_channel_packet_multipage_buffer))
1043                 kfree(payload);
1044 }
1045
1046 static void storvsc_on_io_completion(struct storvsc_device *stor_device,
1047                                   struct vstor_packet *vstor_packet,
1048                                   struct storvsc_cmd_request *request)
1049 {
1050         struct vstor_packet *stor_pkt;
1051         struct hv_device *device = stor_device->device;
1052
1053         stor_pkt = &request->vstor_packet;
1054
1055         /*
1056          * The current SCSI handling on the host side does
1057          * not correctly handle:
1058          * INQUIRY command with page code parameter set to 0x80
1059          * MODE_SENSE command with cmd[2] == 0x1c
1060          *
1061          * Setup srb and scsi status so this won't be fatal.
1062          * We do this so we can distinguish truly fatal failues
1063          * (srb status == 0x4) and off-line the device in that case.
1064          */
1065
1066         if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1067            (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1068                 vstor_packet->vm_srb.scsi_status = 0;
1069                 vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1070         }
1071
1072
1073         /* Copy over the status...etc */
1074         stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1075         stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1076         stor_pkt->vm_srb.sense_info_length =
1077         vstor_packet->vm_srb.sense_info_length;
1078
1079         if (vstor_packet->vm_srb.scsi_status != 0 ||
1080             vstor_packet->vm_srb.srb_status != SRB_STATUS_SUCCESS)
1081                 storvsc_log(device, STORVSC_LOGGING_WARN,
1082                         "cmd 0x%x scsi status 0x%x srb status 0x%x\n",
1083                         stor_pkt->vm_srb.cdb[0],
1084                         vstor_packet->vm_srb.scsi_status,
1085                         vstor_packet->vm_srb.srb_status);
1086
1087         if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
1088                 /* CHECK_CONDITION */
1089                 if (vstor_packet->vm_srb.srb_status &
1090                         SRB_STATUS_AUTOSENSE_VALID) {
1091                         /* autosense data available */
1092
1093                         storvsc_log(device, STORVSC_LOGGING_WARN,
1094                                 "stor pkt %p autosense data valid - len %d\n",
1095                                 request, vstor_packet->vm_srb.sense_info_length);
1096
1097                         memcpy(request->cmd->sense_buffer,
1098                                vstor_packet->vm_srb.sense_data,
1099                                vstor_packet->vm_srb.sense_info_length);
1100
1101                 }
1102         }
1103
1104         stor_pkt->vm_srb.data_transfer_length =
1105         vstor_packet->vm_srb.data_transfer_length;
1106
1107         storvsc_command_completion(request, stor_device);
1108
1109         if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1110                 stor_device->drain_notify)
1111                 wake_up(&stor_device->waiting_to_drain);
1112
1113
1114 }
1115
1116 static void storvsc_on_receive(struct storvsc_device *stor_device,
1117                              struct vstor_packet *vstor_packet,
1118                              struct storvsc_cmd_request *request)
1119 {
1120         struct hv_host_device *host_dev;
1121         switch (vstor_packet->operation) {
1122         case VSTOR_OPERATION_COMPLETE_IO:
1123                 storvsc_on_io_completion(stor_device, vstor_packet, request);
1124                 break;
1125
1126         case VSTOR_OPERATION_REMOVE_DEVICE:
1127         case VSTOR_OPERATION_ENUMERATE_BUS:
1128                 host_dev = shost_priv(stor_device->host);
1129                 queue_work(
1130                         host_dev->handle_error_wq, &host_dev->host_scan_work);
1131                 break;
1132
1133         case VSTOR_OPERATION_FCHBA_DATA:
1134                 cache_wwn(stor_device, vstor_packet);
1135 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1136                 fc_host_node_name(stor_device->host) = stor_device->node_name;
1137                 fc_host_port_name(stor_device->host) = stor_device->port_name;
1138 #endif
1139                 break;
1140         default:
1141                 break;
1142         }
1143 }
1144
1145 static void storvsc_on_channel_callback(void *context)
1146 {
1147         struct vmbus_channel *channel = (struct vmbus_channel *)context;
1148         const struct vmpacket_descriptor *desc;
1149         struct hv_device *device;
1150         struct storvsc_device *stor_device;
1151
1152         if (channel->primary_channel != NULL)
1153                 device = channel->primary_channel->device_obj;
1154         else
1155                 device = channel->device_obj;
1156
1157         stor_device = get_in_stor_device(device);
1158         if (!stor_device)
1159                 return;
1160
1161         foreach_vmbus_pkt(desc, channel) {
1162                 void *packet = hv_pkt_data(desc);
1163                 struct storvsc_cmd_request *request;
1164
1165                 request = (struct storvsc_cmd_request *)
1166                         ((unsigned long)desc->trans_id);
1167
1168                 if (request == &stor_device->init_request ||
1169                     request == &stor_device->reset_request) {
1170                         memcpy(&request->vstor_packet, packet,
1171                                (sizeof(struct vstor_packet) - vmscsi_size_delta));
1172                         complete(&request->wait_event);
1173                 } else {
1174                         storvsc_on_receive(stor_device, packet, request);
1175                 }
1176         }
1177 }
1178
1179 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size,
1180                                   bool is_fc)
1181 {
1182         struct vmstorage_channel_properties props;
1183         int ret;
1184
1185         memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1186
1187         ret = vmbus_open(device->channel,
1188                          ring_size,
1189                          ring_size,
1190                          (void *)&props,
1191                          sizeof(struct vmstorage_channel_properties),
1192                          storvsc_on_channel_callback, device->channel);
1193
1194         if (ret != 0)
1195                 return ret;
1196
1197         ret = storvsc_channel_init(device, is_fc);
1198
1199         return ret;
1200 }
1201
1202 static int storvsc_dev_remove(struct hv_device *device)
1203 {
1204         struct storvsc_device *stor_device;
1205
1206         stor_device = hv_get_drvdata(device);
1207
1208         stor_device->destroy = true;
1209
1210         /* Make sure flag is set before waiting */
1211         wmb();
1212
1213         /*
1214          * At this point, all outbound traffic should be disable. We
1215          * only allow inbound traffic (responses) to proceed so that
1216          * outstanding requests can be completed.
1217          */
1218
1219         storvsc_wait_to_drain(stor_device);
1220
1221         /*
1222          * Since we have already drained, we don't need to busy wait
1223          * as was done in final_release_stor_device()
1224          * Note that we cannot set the ext pointer to NULL until
1225          * we have drained - to drain the outgoing packets, we need to
1226          * allow incoming packets.
1227          */
1228         hv_set_drvdata(device, NULL);
1229
1230         /* Close the channel */
1231         vmbus_close(device->channel);
1232
1233         kfree(stor_device->stor_chns);
1234         kfree(stor_device);
1235         return 0;
1236 }
1237
1238 static struct vmbus_channel *get_og_chn(struct storvsc_device *stor_device,
1239                                         u16 q_num)
1240 {
1241         u16 slot = 0;
1242         u16 hash_qnum;
1243         struct cpumask alloced_mask;
1244         int num_channels, tgt_cpu;
1245
1246         if (stor_device->num_sc == 0)
1247                 return stor_device->device->channel;
1248
1249         /*
1250          * Our channel array is sparsley populated and we
1251          * initiated I/O on a processor/hw-q that does not
1252          * currently have a designated channel. Fix this.
1253          * The strategy is simple:
1254          * I. Ensure NUMA locality
1255          * II. Distribute evenly (best effort)
1256          * III. Mapping is persistent.
1257          */
1258
1259         cpumask_and(&alloced_mask, &stor_device->alloced_cpus,
1260                     cpumask_of_node(cpu_to_node(q_num)));
1261
1262         num_channels = cpumask_weight(&alloced_mask);
1263         if (num_channels == 0)
1264                 return stor_device->device->channel;
1265
1266         hash_qnum = q_num;
1267         while (hash_qnum >= num_channels)
1268                 hash_qnum -= num_channels;
1269
1270         for_each_cpu(tgt_cpu, &alloced_mask) {
1271                 if (slot == hash_qnum)
1272                         break;
1273                 slot++;
1274         }
1275
1276         stor_device->stor_chns[q_num] = stor_device->stor_chns[tgt_cpu];
1277
1278         return stor_device->stor_chns[q_num];
1279 }
1280
1281
1282 static int storvsc_do_io(struct hv_device *device,
1283                          struct storvsc_cmd_request *request, u16 q_num)
1284 {
1285         struct storvsc_device *stor_device;
1286         struct vstor_packet *vstor_packet;
1287         struct vmbus_channel *outgoing_channel;
1288         int ret = 0;
1289         struct cpumask alloced_mask;
1290         int tgt_cpu;
1291
1292         vstor_packet = &request->vstor_packet;
1293         stor_device = get_out_stor_device(device);
1294
1295         if (!stor_device)
1296                 return -ENODEV;
1297
1298
1299         request->device  = device;
1300         /*
1301          * Select an an appropriate channel to send the request out.
1302          */
1303
1304         if (stor_device->stor_chns[q_num] != NULL) {
1305                 outgoing_channel = stor_device->stor_chns[q_num];
1306                 if (outgoing_channel->target_cpu == smp_processor_id()) {
1307                         /*
1308                          * Ideally, we want to pick a different channel if
1309                          * available on the same NUMA node.
1310                          */
1311                         cpumask_and(&alloced_mask, &stor_device->alloced_cpus,
1312                                     cpumask_of_node(cpu_to_node(q_num)));
1313                         for_each_cpu(tgt_cpu, &alloced_mask) {
1314                                 if (tgt_cpu != outgoing_channel->target_cpu) {
1315                                         outgoing_channel =
1316                                         stor_device->stor_chns[tgt_cpu];
1317                                         break;
1318                                 }
1319                         }
1320                 }
1321         } else {
1322                 outgoing_channel = get_og_chn(stor_device, q_num);
1323         }
1324
1325
1326         vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1327
1328         vstor_packet->vm_srb.length = (sizeof(struct vmscsi_request) -
1329                                         vmscsi_size_delta);
1330
1331
1332         vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1333
1334
1335         vstor_packet->vm_srb.data_transfer_length =
1336         request->payload->range.len;
1337
1338         vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1339
1340         if (request->payload->range.len) {
1341
1342                 ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
1343                                 request->payload, request->payload_sz,
1344                                 vstor_packet,
1345                                 (sizeof(struct vstor_packet) -
1346                                 vmscsi_size_delta),
1347                                 (unsigned long)request);
1348         } else {
1349                 ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
1350                                (sizeof(struct vstor_packet) -
1351                                 vmscsi_size_delta),
1352                                (unsigned long)request,
1353                                VM_PKT_DATA_INBAND,
1354                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1355         }
1356
1357         if (ret != 0)
1358                 return ret;
1359
1360         atomic_inc(&stor_device->num_outstanding_req);
1361
1362         return ret;
1363 }
1364
1365 static int storvsc_device_alloc(struct scsi_device *sdevice)
1366 {
1367         /*
1368          * Set blist flag to permit the reading of the VPD pages even when
1369          * the target may claim SPC-2 compliance. MSFT targets currently
1370          * claim SPC-2 compliance while they implement post SPC-2 features.
1371          * With this flag we can correctly handle WRITE_SAME_16 issues.
1372          *
1373          * Hypervisor reports SCSI_UNKNOWN type for DVD ROM device but
1374          * still supports REPORT LUN.
1375          */
1376         sdevice->sdev_bflags = BLIST_REPORTLUN2 | BLIST_TRY_VPD_PAGES;
1377
1378         return 0;
1379 }
1380
1381 static int storvsc_device_configure(struct scsi_device *sdevice)
1382 {
1383
1384         blk_queue_bounce_limit(sdevice->request_queue, BLK_BOUNCE_ANY);
1385
1386         blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1387
1388         /* Ensure there are no gaps in presented sgls */
1389         blk_queue_virt_boundary(sdevice->request_queue, PAGE_SIZE - 1);
1390
1391         sdevice->no_write_same = 1;
1392
1393         /*
1394          * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
1395          * if the device is a MSFT virtual device.  If the host is
1396          * WIN10 or newer, allow write_same.
1397          */
1398         if (!strncmp(sdevice->vendor, "Msft", 4)) {
1399                 switch (vmstor_proto_version) {
1400                 case VMSTOR_PROTO_VERSION_WIN8:
1401                 case VMSTOR_PROTO_VERSION_WIN8_1:
1402                         sdevice->scsi_level = SCSI_SPC_3;
1403                         break;
1404                 }
1405
1406                 if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN10)
1407                         sdevice->no_write_same = 0;
1408         }
1409
1410         return 0;
1411 }
1412
1413 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1414                            sector_t capacity, int *info)
1415 {
1416         sector_t nsect = capacity;
1417         sector_t cylinders = nsect;
1418         int heads, sectors_pt;
1419
1420         /*
1421          * We are making up these values; let us keep it simple.
1422          */
1423         heads = 0xff;
1424         sectors_pt = 0x3f;      /* Sectors per track */
1425         sector_div(cylinders, heads * sectors_pt);
1426         if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1427                 cylinders = 0xffff;
1428
1429         info[0] = heads;
1430         info[1] = sectors_pt;
1431         info[2] = (int)cylinders;
1432
1433         return 0;
1434 }
1435
1436 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1437 {
1438         struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1439         struct hv_device *device = host_dev->dev;
1440
1441         struct storvsc_device *stor_device;
1442         struct storvsc_cmd_request *request;
1443         struct vstor_packet *vstor_packet;
1444         int ret, t;
1445
1446
1447         stor_device = get_out_stor_device(device);
1448         if (!stor_device)
1449                 return FAILED;
1450
1451         request = &stor_device->reset_request;
1452         vstor_packet = &request->vstor_packet;
1453
1454         init_completion(&request->wait_event);
1455
1456         vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1457         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1458         vstor_packet->vm_srb.path_id = stor_device->path_id;
1459
1460         ret = vmbus_sendpacket(device->channel, vstor_packet,
1461                                (sizeof(struct vstor_packet) -
1462                                 vmscsi_size_delta),
1463                                (unsigned long)&stor_device->reset_request,
1464                                VM_PKT_DATA_INBAND,
1465                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1466         if (ret != 0)
1467                 return FAILED;
1468
1469         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1470         if (t == 0)
1471                 return TIMEOUT_ERROR;
1472
1473
1474         /*
1475          * At this point, all outstanding requests in the adapter
1476          * should have been flushed out and return to us
1477          * There is a potential race here where the host may be in
1478          * the process of responding when we return from here.
1479          * Just wait for all in-transit packets to be accounted for
1480          * before we return from here.
1481          */
1482         storvsc_wait_to_drain(stor_device);
1483
1484         return SUCCESS;
1485 }
1486
1487 /*
1488  * The host guarantees to respond to each command, although I/O latencies might
1489  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1490  * chance to perform EH.
1491  */
1492 static enum blk_eh_timer_return storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1493 {
1494 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1495         if (scmnd->device->host->transportt == fc_transport_template)
1496                 return fc_eh_timed_out(scmnd);
1497 #endif
1498         return BLK_EH_RESET_TIMER;
1499 }
1500
1501 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1502 {
1503         bool allowed = true;
1504         u8 scsi_op = scmnd->cmnd[0];
1505
1506         switch (scsi_op) {
1507         /* the host does not handle WRITE_SAME, log accident usage */
1508         case WRITE_SAME:
1509         /*
1510          * smartd sends this command and the host does not handle
1511          * this. So, don't send it.
1512          */
1513         case SET_WINDOW:
1514                 scmnd->result = ILLEGAL_REQUEST << 16;
1515                 allowed = false;
1516                 break;
1517         default:
1518                 break;
1519         }
1520         return allowed;
1521 }
1522
1523 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1524 {
1525         int ret;
1526         struct hv_host_device *host_dev = shost_priv(host);
1527         struct hv_device *dev = host_dev->dev;
1528         struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
1529         int i;
1530         struct scatterlist *sgl;
1531         unsigned int sg_count = 0;
1532         struct vmscsi_request *vm_srb;
1533         struct scatterlist *cur_sgl;
1534         struct vmbus_packet_mpb_array  *payload;
1535         u32 payload_sz;
1536         u32 length;
1537
1538         if (vmstor_proto_version <= VMSTOR_PROTO_VERSION_WIN8) {
1539                 /*
1540                  * On legacy hosts filter unimplemented commands.
1541                  * Future hosts are expected to correctly handle
1542                  * unsupported commands. Furthermore, it is
1543                  * possible that some of the currently
1544                  * unsupported commands maybe supported in
1545                  * future versions of the host.
1546                  */
1547                 if (!storvsc_scsi_cmd_ok(scmnd)) {
1548                         scmnd->scsi_done(scmnd);
1549                         return 0;
1550                 }
1551         }
1552
1553         /* Setup the cmd request */
1554         cmd_request->cmd = scmnd;
1555
1556         vm_srb = &cmd_request->vstor_packet.vm_srb;
1557         vm_srb->win8_extension.time_out_value = 60;
1558
1559         vm_srb->win8_extension.srb_flags |=
1560                 SRB_FLAGS_DISABLE_SYNCH_TRANSFER;
1561
1562         if (scmnd->device->tagged_supported) {
1563                 vm_srb->win8_extension.srb_flags |=
1564                 (SRB_FLAGS_QUEUE_ACTION_ENABLE | SRB_FLAGS_NO_QUEUE_FREEZE);
1565                 vm_srb->win8_extension.queue_tag = SP_UNTAGGED;
1566                 vm_srb->win8_extension.queue_action = SRB_SIMPLE_TAG_REQUEST;
1567         }
1568
1569         /* Build the SRB */
1570         switch (scmnd->sc_data_direction) {
1571         case DMA_TO_DEVICE:
1572                 vm_srb->data_in = WRITE_TYPE;
1573                 vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_OUT;
1574                 break;
1575         case DMA_FROM_DEVICE:
1576                 vm_srb->data_in = READ_TYPE;
1577                 vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_IN;
1578                 break;
1579         case DMA_NONE:
1580                 vm_srb->data_in = UNKNOWN_TYPE;
1581                 vm_srb->win8_extension.srb_flags |= SRB_FLAGS_NO_DATA_TRANSFER;
1582                 break;
1583         default:
1584                 /*
1585                  * This is DMA_BIDIRECTIONAL or something else we are never
1586                  * supposed to see here.
1587                  */
1588                 WARN(1, "Unexpected data direction: %d\n",
1589                      scmnd->sc_data_direction);
1590                 return -EINVAL;
1591         }
1592
1593
1594         vm_srb->port_number = host_dev->port;
1595         vm_srb->path_id = scmnd->device->channel;
1596         vm_srb->target_id = scmnd->device->id;
1597         vm_srb->lun = scmnd->device->lun;
1598
1599         vm_srb->cdb_length = scmnd->cmd_len;
1600
1601         memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1602
1603         sgl = (struct scatterlist *)scsi_sglist(scmnd);
1604         sg_count = scsi_sg_count(scmnd);
1605
1606         length = scsi_bufflen(scmnd);
1607         payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
1608         payload_sz = sizeof(cmd_request->mpb);
1609
1610         if (sg_count) {
1611                 if (sg_count > MAX_PAGE_BUFFER_COUNT) {
1612
1613                         payload_sz = (sg_count * sizeof(u64) +
1614                                       sizeof(struct vmbus_packet_mpb_array));
1615                         payload = kzalloc(payload_sz, GFP_ATOMIC);
1616                         if (!payload)
1617                                 return SCSI_MLQUEUE_DEVICE_BUSY;
1618                 }
1619
1620                 payload->range.len = length;
1621                 payload->range.offset = sgl[0].offset;
1622
1623                 cur_sgl = sgl;
1624                 for (i = 0; i < sg_count; i++) {
1625                         payload->range.pfn_array[i] =
1626                                 page_to_pfn(sg_page((cur_sgl)));
1627                         cur_sgl = sg_next(cur_sgl);
1628                 }
1629         }
1630
1631         cmd_request->payload = payload;
1632         cmd_request->payload_sz = payload_sz;
1633
1634         /* Invokes the vsc to start an IO */
1635         ret = storvsc_do_io(dev, cmd_request, get_cpu());
1636         put_cpu();
1637
1638         if (ret == -EAGAIN) {
1639                 if (payload_sz > sizeof(cmd_request->mpb))
1640                         kfree(payload);
1641                 /* no more space */
1642                 return SCSI_MLQUEUE_DEVICE_BUSY;
1643         }
1644
1645         return 0;
1646 }
1647
1648 static struct scsi_host_template scsi_driver = {
1649         .module =               THIS_MODULE,
1650         .name =                 "storvsc_host_t",
1651         .cmd_size =             sizeof(struct storvsc_cmd_request),
1652         .bios_param =           storvsc_get_chs,
1653         .queuecommand =         storvsc_queuecommand,
1654         .eh_host_reset_handler =        storvsc_host_reset_handler,
1655         .proc_name =            "storvsc_host",
1656         .eh_timed_out =         storvsc_eh_timed_out,
1657         .slave_alloc =          storvsc_device_alloc,
1658         .slave_configure =      storvsc_device_configure,
1659         .cmd_per_lun =          255,
1660         .this_id =              -1,
1661         .use_clustering =       ENABLE_CLUSTERING,
1662         /* Make sure we dont get a sg segment crosses a page boundary */
1663         .dma_boundary =         PAGE_SIZE-1,
1664         .no_write_same =        1,
1665         .track_queue_depth =    1,
1666 };
1667
1668 enum {
1669         SCSI_GUID,
1670         IDE_GUID,
1671         SFC_GUID,
1672 };
1673
1674 static const struct hv_vmbus_device_id id_table[] = {
1675         /* SCSI guid */
1676         { HV_SCSI_GUID,
1677           .driver_data = SCSI_GUID
1678         },
1679         /* IDE guid */
1680         { HV_IDE_GUID,
1681           .driver_data = IDE_GUID
1682         },
1683         /* Fibre Channel GUID */
1684         {
1685           HV_SYNTHFC_GUID,
1686           .driver_data = SFC_GUID
1687         },
1688         { },
1689 };
1690
1691 MODULE_DEVICE_TABLE(vmbus, id_table);
1692
1693 static int storvsc_probe(struct hv_device *device,
1694                         const struct hv_vmbus_device_id *dev_id)
1695 {
1696         int ret;
1697         int num_cpus = num_online_cpus();
1698         struct Scsi_Host *host;
1699         struct hv_host_device *host_dev;
1700         bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1701         bool is_fc = ((dev_id->driver_data == SFC_GUID) ? true : false);
1702         int target = 0;
1703         struct storvsc_device *stor_device;
1704         int max_luns_per_target;
1705         int max_targets;
1706         int max_channels;
1707         int max_sub_channels = 0;
1708
1709         /*
1710          * Based on the windows host we are running on,
1711          * set state to properly communicate with the host.
1712          */
1713
1714         if (vmbus_proto_version < VERSION_WIN8) {
1715                 max_luns_per_target = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1716                 max_targets = STORVSC_IDE_MAX_TARGETS;
1717                 max_channels = STORVSC_IDE_MAX_CHANNELS;
1718         } else {
1719                 max_luns_per_target = STORVSC_MAX_LUNS_PER_TARGET;
1720                 max_targets = STORVSC_MAX_TARGETS;
1721                 max_channels = STORVSC_MAX_CHANNELS;
1722                 /*
1723                  * On Windows8 and above, we support sub-channels for storage.
1724                  * The number of sub-channels offerred is based on the number of
1725                  * VCPUs in the guest.
1726                  */
1727                 max_sub_channels = (num_cpus / storvsc_vcpus_per_sub_channel);
1728         }
1729
1730         scsi_driver.can_queue = (max_outstanding_req_per_channel *
1731                                  (max_sub_channels + 1));
1732
1733         host = scsi_host_alloc(&scsi_driver,
1734                                sizeof(struct hv_host_device));
1735         if (!host)
1736                 return -ENOMEM;
1737
1738         host_dev = shost_priv(host);
1739         memset(host_dev, 0, sizeof(struct hv_host_device));
1740
1741         host_dev->port = host->host_no;
1742         host_dev->dev = device;
1743         host_dev->host = host;
1744
1745
1746         stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1747         if (!stor_device) {
1748                 ret = -ENOMEM;
1749                 goto err_out0;
1750         }
1751
1752         stor_device->destroy = false;
1753         stor_device->open_sub_channel = false;
1754         init_waitqueue_head(&stor_device->waiting_to_drain);
1755         stor_device->device = device;
1756         stor_device->host = host;
1757         hv_set_drvdata(device, stor_device);
1758
1759         stor_device->port_number = host->host_no;
1760         ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size, is_fc);
1761         if (ret)
1762                 goto err_out1;
1763
1764         host_dev->path = stor_device->path_id;
1765         host_dev->target = stor_device->target_id;
1766
1767         switch (dev_id->driver_data) {
1768         case SFC_GUID:
1769                 host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
1770                 host->max_id = STORVSC_FC_MAX_TARGETS;
1771                 host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
1772 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1773                 host->transportt = fc_transport_template;
1774 #endif
1775                 break;
1776
1777         case SCSI_GUID:
1778                 host->max_lun = max_luns_per_target;
1779                 host->max_id = max_targets;
1780                 host->max_channel = max_channels - 1;
1781                 break;
1782
1783         default:
1784                 host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1785                 host->max_id = STORVSC_IDE_MAX_TARGETS;
1786                 host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
1787                 break;
1788         }
1789         /* max cmd length */
1790         host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1791
1792         /*
1793          * set the table size based on the info we got
1794          * from the host.
1795          */
1796         host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT);
1797         /*
1798          * Set the number of HW queues we are supporting.
1799          */
1800         if (stor_device->num_sc != 0)
1801                 host->nr_hw_queues = stor_device->num_sc + 1;
1802
1803         /*
1804          * Set the error handler work queue.
1805          */
1806         host_dev->handle_error_wq =
1807                         alloc_ordered_workqueue("storvsc_error_wq_%d",
1808                                                 WQ_MEM_RECLAIM,
1809                                                 host->host_no);
1810         if (!host_dev->handle_error_wq)
1811                 goto err_out2;
1812         INIT_WORK(&host_dev->host_scan_work, storvsc_host_scan);
1813         /* Register the HBA and start the scsi bus scan */
1814         ret = scsi_add_host(host, &device->device);
1815         if (ret != 0)
1816                 goto err_out3;
1817
1818         if (!dev_is_ide) {
1819                 scsi_scan_host(host);
1820         } else {
1821                 target = (device->dev_instance.b[5] << 8 |
1822                          device->dev_instance.b[4]);
1823                 ret = scsi_add_device(host, 0, target, 0);
1824                 if (ret)
1825                         goto err_out4;
1826         }
1827 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1828         if (host->transportt == fc_transport_template) {
1829                 struct fc_rport_identifiers ids = {
1830                         .roles = FC_PORT_ROLE_FCP_DUMMY_INITIATOR,
1831                 };
1832
1833                 fc_host_node_name(host) = stor_device->node_name;
1834                 fc_host_port_name(host) = stor_device->port_name;
1835                 stor_device->rport = fc_remote_port_add(host, 0, &ids);
1836                 if (!stor_device->rport)
1837                         goto err_out4;
1838         }
1839 #endif
1840         return 0;
1841
1842 err_out4:
1843         scsi_remove_host(host);
1844
1845 err_out3:
1846         destroy_workqueue(host_dev->handle_error_wq);
1847
1848 err_out2:
1849         /*
1850          * Once we have connected with the host, we would need to
1851          * to invoke storvsc_dev_remove() to rollback this state and
1852          * this call also frees up the stor_device; hence the jump around
1853          * err_out1 label.
1854          */
1855         storvsc_dev_remove(device);
1856         goto err_out0;
1857
1858 err_out1:
1859         kfree(stor_device->stor_chns);
1860         kfree(stor_device);
1861
1862 err_out0:
1863         scsi_host_put(host);
1864         return ret;
1865 }
1866
1867 static int storvsc_remove(struct hv_device *dev)
1868 {
1869         struct storvsc_device *stor_device = hv_get_drvdata(dev);
1870         struct Scsi_Host *host = stor_device->host;
1871         struct hv_host_device *host_dev = shost_priv(host);
1872
1873 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1874         if (host->transportt == fc_transport_template) {
1875                 fc_remote_port_delete(stor_device->rport);
1876                 fc_remove_host(host);
1877         }
1878 #endif
1879         destroy_workqueue(host_dev->handle_error_wq);
1880         scsi_remove_host(host);
1881         storvsc_dev_remove(dev);
1882         scsi_host_put(host);
1883
1884         return 0;
1885 }
1886
1887 static struct hv_driver storvsc_drv = {
1888         .name = KBUILD_MODNAME,
1889         .id_table = id_table,
1890         .probe = storvsc_probe,
1891         .remove = storvsc_remove,
1892 };
1893
1894 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1895 static struct fc_function_template fc_transport_functions = {
1896         .show_host_node_name = 1,
1897         .show_host_port_name = 1,
1898 };
1899 #endif
1900
1901 static int __init storvsc_drv_init(void)
1902 {
1903         int ret;
1904
1905         /*
1906          * Divide the ring buffer data size (which is 1 page less
1907          * than the ring buffer size since that page is reserved for
1908          * the ring buffer indices) by the max request size (which is
1909          * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
1910          */
1911         max_outstanding_req_per_channel =
1912                 ((storvsc_ringbuffer_size - PAGE_SIZE) /
1913                 ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
1914                 sizeof(struct vstor_packet) + sizeof(u64) -
1915                 vmscsi_size_delta,
1916                 sizeof(u64)));
1917
1918 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1919         fc_transport_template = fc_attach_transport(&fc_transport_functions);
1920         if (!fc_transport_template)
1921                 return -ENODEV;
1922 #endif
1923
1924         ret = vmbus_driver_register(&storvsc_drv);
1925
1926 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1927         if (ret)
1928                 fc_release_transport(fc_transport_template);
1929 #endif
1930
1931         return ret;
1932 }
1933
1934 static void __exit storvsc_drv_exit(void)
1935 {
1936         vmbus_driver_unregister(&storvsc_drv);
1937 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1938         fc_release_transport(fc_transport_template);
1939 #endif
1940 }
1941
1942 MODULE_LICENSE("GPL");
1943 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
1944 module_init(storvsc_drv_init);
1945 module_exit(storvsc_drv_exit);