drivers/scsi/storvsc_drv.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2009, Microsoft Corporation.
   4  *
   5  * Authors:
   6  *   Haiyang Zhang <haiyangz@microsoft.com>
   7  *   Hank Janssen  <hjanssen@microsoft.com>
   8  *   K. Y. Srinivasan <kys@microsoft.com>
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/wait.h>
  13 #include <linux/sched.h>
  14 #include <linux/completion.h>
  15 #include <linux/string.h>
  16 #include <linux/mm.h>
  17 #include <linux/delay.h>
  18 #include <linux/init.h>
  19 #include <linux/slab.h>
  20 #include <linux/module.h>
  21 #include <linux/device.h>
  22 #include <linux/hyperv.h>
  23 #include <linux/blkdev.h>
  24 #include <scsi/scsi.h>
  25 #include <scsi/scsi_cmnd.h>
  26 #include <scsi/scsi_host.h>
  27 #include <scsi/scsi_device.h>
  28 #include <scsi/scsi_tcq.h>
  29 #include <scsi/scsi_eh.h>
  30 #include <scsi/scsi_devinfo.h>
  31 #include <scsi/scsi_dbg.h>
  32 #include <scsi/scsi_transport_fc.h>
  33 #include <scsi/scsi_transport.h>
  34
  35 /*
  36  * All wire protocol details (storage protocol between the guest and the host)
  37  * are consolidated here.
  38  *
  39  * Begin protocol definitions.
  40  */
  41
  42 /*
  43  * Version history:
  44  * V1 Beta: 0.1
  45  * V1 RC < 2008/1/31: 1.0
  46  * V1 RC > 2008/1/31:  2.0
  47  * Win7: 4.2
  48  * Win8: 5.1
  49  * Win8.1: 6.0
  50  * Win10: 6.2
  51  */
  52
  53 #define VMSTOR_PROTO_VERSION(MAJOR_, MINOR_)    ((((MAJOR_) & 0xff) << 8) | \
  54                                                 (((MINOR_) & 0xff)))
  55
  56 #define VMSTOR_PROTO_VERSION_WIN6       VMSTOR_PROTO_VERSION(2, 0)
  57 #define VMSTOR_PROTO_VERSION_WIN7       VMSTOR_PROTO_VERSION(4, 2)
  58 #define VMSTOR_PROTO_VERSION_WIN8       VMSTOR_PROTO_VERSION(5, 1)
  59 #define VMSTOR_PROTO_VERSION_WIN8_1     VMSTOR_PROTO_VERSION(6, 0)
  60 #define VMSTOR_PROTO_VERSION_WIN10      VMSTOR_PROTO_VERSION(6, 2)
  61
  62 /*  Packet structure describing virtual storage requests. */
  63 enum vstor_packet_operation {
  64         VSTOR_OPERATION_COMPLETE_IO             = 1,
  65         VSTOR_OPERATION_REMOVE_DEVICE           = 2,
  66         VSTOR_OPERATION_EXECUTE_SRB             = 3,
  67         VSTOR_OPERATION_RESET_LUN               = 4,
  68         VSTOR_OPERATION_RESET_ADAPTER           = 5,
  69         VSTOR_OPERATION_RESET_BUS               = 6,
  70         VSTOR_OPERATION_BEGIN_INITIALIZATION    = 7,
  71         VSTOR_OPERATION_END_INITIALIZATION      = 8,
  72         VSTOR_OPERATION_QUERY_PROTOCOL_VERSION  = 9,
  73         VSTOR_OPERATION_QUERY_PROPERTIES        = 10,
  74         VSTOR_OPERATION_ENUMERATE_BUS           = 11,
  75         VSTOR_OPERATION_FCHBA_DATA              = 12,
  76         VSTOR_OPERATION_CREATE_SUB_CHANNELS     = 13,
  77         VSTOR_OPERATION_MAXIMUM                 = 13
  78 };
  79
  80 /*
  81  * WWN packet for Fibre Channel HBA
  82  */
  83
  84 struct hv_fc_wwn_packet {
  85         u8      primary_active;
  86         u8      reserved1[3];
  87         u8      primary_port_wwn[8];
  88         u8      primary_node_wwn[8];
  89         u8      secondary_port_wwn[8];
  90         u8      secondary_node_wwn[8];
  91 };
  92
  93
  94
  95 /*
  96  * SRB Flag Bits
  97  */
  98
  99 #define SRB_FLAGS_QUEUE_ACTION_ENABLE           0x00000002
 100 #define SRB_FLAGS_DISABLE_DISCONNECT            0x00000004
 101 #define SRB_FLAGS_DISABLE_SYNCH_TRANSFER        0x00000008
 102 #define SRB_FLAGS_BYPASS_FROZEN_QUEUE           0x00000010
 103 #define SRB_FLAGS_DISABLE_AUTOSENSE             0x00000020
 104 #define SRB_FLAGS_DATA_IN                       0x00000040
 105 #define SRB_FLAGS_DATA_OUT                      0x00000080
 106 #define SRB_FLAGS_NO_DATA_TRANSFER              0x00000000
 107 #define SRB_FLAGS_UNSPECIFIED_DIRECTION (SRB_FLAGS_DATA_IN | SRB_FLAGS_DATA_OUT)
 108 #define SRB_FLAGS_NO_QUEUE_FREEZE               0x00000100
 109 #define SRB_FLAGS_ADAPTER_CACHE_ENABLE          0x00000200
 110 #define SRB_FLAGS_FREE_SENSE_BUFFER             0x00000400
 111
 112 /*
 113  * This flag indicates the request is part of the workflow for processing a D3.
 114  */
 115 #define SRB_FLAGS_D3_PROCESSING                 0x00000800
 116 #define SRB_FLAGS_IS_ACTIVE                     0x00010000
 117 #define SRB_FLAGS_ALLOCATED_FROM_ZONE           0x00020000
 118 #define SRB_FLAGS_SGLIST_FROM_POOL              0x00040000
 119 #define SRB_FLAGS_BYPASS_LOCKED_QUEUE           0x00080000
 120 #define SRB_FLAGS_NO_KEEP_AWAKE                 0x00100000
 121 #define SRB_FLAGS_PORT_DRIVER_ALLOCSENSE        0x00200000
 122 #define SRB_FLAGS_PORT_DRIVER_SENSEHASPORT      0x00400000
 123 #define SRB_FLAGS_DONT_START_NEXT_PACKET        0x00800000
 124 #define SRB_FLAGS_PORT_DRIVER_RESERVED          0x0F000000
 125 #define SRB_FLAGS_CLASS_DRIVER_RESERVED         0xF0000000
 126
 127 #define SP_UNTAGGED                     ((unsigned char) ~0)
 128 #define SRB_SIMPLE_TAG_REQUEST          0x20
 129
 130 /*
 131  * Platform neutral description of a scsi request -
 132  * this remains the same across the write regardless of 32/64 bit
 133  * note: it's patterned off the SCSI_PASS_THROUGH structure
 134  */
 135 #define STORVSC_MAX_CMD_LEN                     0x10
 136
 137 #define POST_WIN7_STORVSC_SENSE_BUFFER_SIZE     0x14
 138 #define PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE      0x12
 139
 140 #define STORVSC_SENSE_BUFFER_SIZE               0x14
 141 #define STORVSC_MAX_BUF_LEN_WITH_PADDING        0x14
 142
 143 /*
 144  * Sense buffer size changed in win8; have a run-time
 145  * variable to track the size we should use.  This value will
 146  * likely change during protocol negotiation but it is valid
 147  * to start by assuming pre-Win8.
 148  */
 149 static int sense_buffer_size = PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE;
 150
 151 /*
 152  * The storage protocol version is determined during the
 153  * initial exchange with the host.  It will indicate which
 154  * storage functionality is available in the host.
 155 */
 156 static int vmstor_proto_version;
 157
 158 #define STORVSC_LOGGING_NONE    0
 159 #define STORVSC_LOGGING_ERROR   1
 160 #define STORVSC_LOGGING_WARN    2
 161
 162 static int logging_level = STORVSC_LOGGING_ERROR;
 163 module_param(logging_level, int, S_IRUGO|S_IWUSR);
 164 MODULE_PARM_DESC(logging_level,
 165         "Logging level, 0 - None, 1 - Error (default), 2 - Warning.");
 166
 167 static inline bool do_logging(int level)
 168 {
 169         return logging_level >= level;
 170 }
 171
 172 #define storvsc_log(dev, level, fmt, ...)                       \
 173 do {                                                            \
 174         if (do_logging(level))                                  \
 175                 dev_warn(&(dev)->device, fmt, ##__VA_ARGS__);   \
 176 } while (0)
 177
 178 struct vmscsi_win8_extension {
 179         /*
 180          * The following were added in Windows 8
 181          */
 182         u16 reserve;
 183         u8  queue_tag;
 184         u8  queue_action;
 185         u32 srb_flags;
 186         u32 time_out_value;
 187         u32 queue_sort_ey;
 188 } __packed;
 189
 190 struct vmscsi_request {
 191         u16 length;
 192         u8 srb_status;
 193         u8 scsi_status;
 194
 195         u8  port_number;
 196         u8  path_id;
 197         u8  target_id;
 198         u8  lun;
 199
 200         u8  cdb_length;
 201         u8  sense_info_length;
 202         u8  data_in;
 203         u8  reserved;
 204
 205         u32 data_transfer_length;
 206
 207         union {
 208                 u8 cdb[STORVSC_MAX_CMD_LEN];
 209                 u8 sense_data[STORVSC_SENSE_BUFFER_SIZE];
 210                 u8 reserved_array[STORVSC_MAX_BUF_LEN_WITH_PADDING];
 211         };
 212         /*
 213          * The following was added in win8.
 214          */
 215         struct vmscsi_win8_extension win8_extension;
 216
 217 } __attribute((packed));
 218
 219
 220 /*
 221  * The size of the vmscsi_request has changed in win8. The
 222  * additional size is because of new elements added to the
 223  * structure. These elements are valid only when we are talking
 224  * to a win8 host.
 225  * Track the correction to size we need to apply. This value
 226  * will likely change during protocol negotiation but it is
 227  * valid to start by assuming pre-Win8.
 228  */
 229 static int vmscsi_size_delta = sizeof(struct vmscsi_win8_extension);
 230
 231 /*
 232  * The list of storage protocols in order of preference.
 233  */
 234 struct vmstor_protocol {
 235         int protocol_version;
 236         int sense_buffer_size;
 237         int vmscsi_size_delta;
 238 };
 239
 240
 241 static const struct vmstor_protocol vmstor_protocols[] = {
 242         {
 243                 VMSTOR_PROTO_VERSION_WIN10,
 244                 POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
 245                 0
 246         },
 247         {
 248                 VMSTOR_PROTO_VERSION_WIN8_1,
 249                 POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
 250                 0
 251         },
 252         {
 253                 VMSTOR_PROTO_VERSION_WIN8,
 254                 POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
 255                 0
 256         },
 257         {
 258                 VMSTOR_PROTO_VERSION_WIN7,
 259                 PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
 260                 sizeof(struct vmscsi_win8_extension),
 261         },
 262         {
 263                 VMSTOR_PROTO_VERSION_WIN6,
 264                 PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
 265                 sizeof(struct vmscsi_win8_extension),
 266         }
 267 };
 268
 269
 270 /*
 271  * This structure is sent during the initialization phase to get the different
 272  * properties of the channel.
 273  */
 274
 275 #define STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL          0x1
 276
 277 struct vmstorage_channel_properties {
 278         u32 reserved;
 279         u16 max_channel_cnt;
 280         u16 reserved1;
 281
 282         u32 flags;
 283         u32   max_transfer_bytes;
 284
 285         u64  reserved2;
 286 } __packed;
 287
 288 /*  This structure is sent during the storage protocol negotiations. */
 289 struct vmstorage_protocol_version {
 290         /* Major (MSW) and minor (LSW) version numbers. */
 291         u16 major_minor;
 292
 293         /*
 294          * Revision number is auto-incremented whenever this file is changed
 295          * (See FILL_VMSTOR_REVISION macro above).  Mismatch does not
 296          * definitely indicate incompatibility--but it does indicate mismatched
 297          * builds.
 298          * This is only used on the windows side. Just set it to 0.
 299          */
 300         u16 revision;
 301 } __packed;
 302
 303 /* Channel Property Flags */
 304 #define STORAGE_CHANNEL_REMOVABLE_FLAG          0x1
 305 #define STORAGE_CHANNEL_EMULATED_IDE_FLAG       0x2
 306
 307 struct vstor_packet {
 308         /* Requested operation type */
 309         enum vstor_packet_operation operation;
 310
 311         /*  Flags - see below for values */
 312         u32 flags;
 313
 314         /* Status of the request returned from the server side. */
 315         u32 status;
 316
 317         /* Data payload area */
 318         union {
 319                 /*
 320                  * Structure used to forward SCSI commands from the
 321                  * client to the server.
 322                  */
 323                 struct vmscsi_request vm_srb;
 324
 325                 /* Structure used to query channel properties. */
 326                 struct vmstorage_channel_properties storage_channel_properties;
 327
 328                 /* Used during version negotiations. */
 329                 struct vmstorage_protocol_version version;
 330
 331                 /* Fibre channel address packet */
 332                 struct hv_fc_wwn_packet wwn_packet;
 333
 334                 /* Number of sub-channels to create */
 335                 u16 sub_channel_count;
 336
 337                 /* This will be the maximum of the union members */
 338                 u8  buffer[0x34];
 339         };
 340 } __packed;
 341
 342 /*
 343  * Packet Flags:
 344  *
 345  * This flag indicates that the server should send back a completion for this
 346  * packet.
 347  */
 348
 349 #define REQUEST_COMPLETION_FLAG 0x1
 350
 351 /* Matches Windows-end */
 352 enum storvsc_request_type {
 353         WRITE_TYPE = 0,
 354         READ_TYPE,
 355         UNKNOWN_TYPE,
 356 };
 357
 358 /*
 359  * SRB status codes and masks; a subset of the codes used here.
 360  */
 361
 362 #define SRB_STATUS_AUTOSENSE_VALID      0x80
 363 #define SRB_STATUS_QUEUE_FROZEN         0x40
 364 #define SRB_STATUS_INVALID_LUN  0x20
 365 #define SRB_STATUS_SUCCESS      0x01
 366 #define SRB_STATUS_ABORTED      0x02
 367 #define SRB_STATUS_ERROR        0x04
 368 #define SRB_STATUS_DATA_OVERRUN 0x12
 369
 370 #define SRB_STATUS(status) \
 371         (status & ~(SRB_STATUS_AUTOSENSE_VALID | SRB_STATUS_QUEUE_FROZEN))
 372 /*
 373  * This is the end of Protocol specific defines.
 374  */
 375
 376 static int storvsc_ringbuffer_size = (128 * 1024);
 377 static u32 max_outstanding_req_per_channel;
 378 static int storvsc_change_queue_depth(struct scsi_device *sdev, int queue_depth);
 379
 380 static int storvsc_vcpus_per_sub_channel = 4;
 381
 382 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
 383 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
 384
 385 module_param(storvsc_vcpus_per_sub_channel, int, S_IRUGO);
 386 MODULE_PARM_DESC(storvsc_vcpus_per_sub_channel, "Ratio of VCPUs to subchannels");
 387
 388 static int ring_avail_percent_lowater = 10;
 389 module_param(ring_avail_percent_lowater, int, S_IRUGO);
 390 MODULE_PARM_DESC(ring_avail_percent_lowater,
 391                 "Select a channel if available ring size > this in percent");
 392
 393 /*
 394  * Timeout in seconds for all devices managed by this driver.
 395  */
 396 static int storvsc_timeout = 180;
 397
 398 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
 399 static struct scsi_transport_template *fc_transport_template;
 400 #endif
 401
 402 static void storvsc_on_channel_callback(void *context);
 403
 404 #define STORVSC_MAX_LUNS_PER_TARGET                     255
 405 #define STORVSC_MAX_TARGETS                             2
 406 #define STORVSC_MAX_CHANNELS                            8
 407
 408 #define STORVSC_FC_MAX_LUNS_PER_TARGET                  255
 409 #define STORVSC_FC_MAX_TARGETS                          128
 410 #define STORVSC_FC_MAX_CHANNELS                         8
 411
 412 #define STORVSC_IDE_MAX_LUNS_PER_TARGET                 64
 413 #define STORVSC_IDE_MAX_TARGETS                         1
 414 #define STORVSC_IDE_MAX_CHANNELS                        1
 415
 416 struct storvsc_cmd_request {
 417         struct scsi_cmnd *cmd;
 418
 419         struct hv_device *device;
 420
 421         /* Synchronize the request/response if needed */
 422         struct completion wait_event;
 423
 424         struct vmbus_channel_packet_multipage_buffer mpb;
 425         struct vmbus_packet_mpb_array *payload;
 426         u32 payload_sz;
 427
 428         struct vstor_packet vstor_packet;
 429 };
 430
 431
 432 /* A storvsc device is a device object that contains a vmbus channel */
 433 struct storvsc_device {
 434         struct hv_device *device;
 435
 436         bool     destroy;
 437         bool     drain_notify;
 438         atomic_t num_outstanding_req;
 439         struct Scsi_Host *host;
 440
 441         wait_queue_head_t waiting_to_drain;
 442
 443         /*
 444          * Each unique Port/Path/Target represents 1 channel ie scsi
 445          * controller. In reality, the pathid, targetid is always 0
 446          * and the port is set by us
 447          */
 448         unsigned int port_number;
 449         unsigned char path_id;
 450         unsigned char target_id;
 451
 452         /*
 453          * Max I/O, the device can support.
 454          */
 455         u32   max_transfer_bytes;
 456         /*
 457          * Number of sub-channels we will open.
 458          */
 459         u16 num_sc;
 460         struct vmbus_channel **stor_chns;
 461         /*
 462          * Mask of CPUs bound to subchannels.
 463          */
 464         struct cpumask alloced_cpus;
 465         /* Used for vsc/vsp channel reset process */
 466         struct storvsc_cmd_request init_request;
 467         struct storvsc_cmd_request reset_request;
 468         /*
 469          * Currently active port and node names for FC devices.
 470          */
 471         u64 node_name;
 472         u64 port_name;
 473 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
 474         struct fc_rport *rport;
 475 #endif
 476 };
 477
 478 struct hv_host_device {
 479         struct hv_device *dev;
 480         unsigned int port;
 481         unsigned char path;
 482         unsigned char target;
 483         struct workqueue_struct *handle_error_wq;
 484         struct work_struct host_scan_work;
 485         struct Scsi_Host *host;
 486 };
 487
 488 struct storvsc_scan_work {
 489         struct work_struct work;
 490         struct Scsi_Host *host;
 491         u8 lun;
 492         u8 tgt_id;
 493 };
 494
 495 static void storvsc_device_scan(struct work_struct *work)
 496 {
 497         struct storvsc_scan_work *wrk;
 498         struct scsi_device *sdev;
 499
 500         wrk = container_of(work, struct storvsc_scan_work, work);
 501
 502         sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
 503         if (!sdev)
 504                 goto done;
 505         scsi_rescan_device(&sdev->sdev_gendev);
 506         scsi_device_put(sdev);
 507
 508 done:
 509         kfree(wrk);
 510 }
 511
 512 static void storvsc_host_scan(struct work_struct *work)
 513 {
 514         struct Scsi_Host *host;
 515         struct scsi_device *sdev;
 516         struct hv_host_device *host_device =
 517                 container_of(work, struct hv_host_device, host_scan_work);
 518
 519         host = host_device->host;
 520         /*
 521          * Before scanning the host, first check to see if any of the
 522          * currrently known devices have been hot removed. We issue a
 523          * "unit ready" command against all currently known devices.
 524          * This I/O will result in an error for devices that have been
 525          * removed. As part of handling the I/O error, we remove the device.
 526          *
 527          * When a LUN is added or removed, the host sends us a signal to
 528          * scan the host. Thus we are forced to discover the LUNs that
 529          * may have been removed this way.
 530          */
 531         mutex_lock(&host->scan_mutex);
 532         shost_for_each_device(sdev, host)
 533                 scsi_test_unit_ready(sdev, 1, 1, NULL);
 534         mutex_unlock(&host->scan_mutex);
 535         /*
 536          * Now scan the host to discover LUNs that may have been added.
 537          */
 538         scsi_scan_host(host);
 539 }
 540
 541 static void storvsc_remove_lun(struct work_struct *work)
 542 {
 543         struct storvsc_scan_work *wrk;
 544         struct scsi_device *sdev;
 545
 546         wrk = container_of(work, struct storvsc_scan_work, work);
 547         if (!scsi_host_get(wrk->host))
 548                 goto done;
 549
 550         sdev = scsi_device_lookup(wrk->host, 0, wrk->tgt_id, wrk->lun);
 551
 552         if (sdev) {
 553                 scsi_remove_device(sdev);
 554                 scsi_device_put(sdev);
 555         }
 556         scsi_host_put(wrk->host);
 557
 558 done:
 559         kfree(wrk);
 560 }
 561
 562
 563 /*
 564  * We can get incoming messages from the host that are not in response to
 565  * messages that we have sent out. An example of this would be messages
 566  * received by the guest to notify dynamic addition/removal of LUNs. To
 567  * deal with potential race conditions where the driver may be in the
 568  * midst of being unloaded when we might receive an unsolicited message
 569  * from the host, we have implemented a mechanism to gurantee sequential
 570  * consistency:
 571  *
 572  * 1) Once the device is marked as being destroyed, we will fail all
 573  *    outgoing messages.
 574  * 2) We permit incoming messages when the device is being destroyed,
 575  *    only to properly account for messages already sent out.
 576  */
 577
 578 static inline struct storvsc_device *get_out_stor_device(
 579                                         struct hv_device *device)
 580 {
 581         struct storvsc_device *stor_device;
 582
 583         stor_device = hv_get_drvdata(device);
 584
 585         if (stor_device && stor_device->destroy)
 586                 stor_device = NULL;
 587
 588         return stor_device;
 589 }
 590
 591
 592 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
 593 {
 594         dev->drain_notify = true;
 595         wait_event(dev->waiting_to_drain,
 596                    atomic_read(&dev->num_outstanding_req) == 0);
 597         dev->drain_notify = false;
 598 }
 599
 600 static inline struct storvsc_device *get_in_stor_device(
 601                                         struct hv_device *device)
 602 {
 603         struct storvsc_device *stor_device;
 604
 605         stor_device = hv_get_drvdata(device);
 606
 607         if (!stor_device)
 608                 goto get_in_err;
 609
 610         /*
 611          * If the device is being destroyed; allow incoming
 612          * traffic only to cleanup outstanding requests.
 613          */
 614
 615         if (stor_device->destroy  &&
 616                 (atomic_read(&stor_device->num_outstanding_req) == 0))
 617                 stor_device = NULL;
 618
 619 get_in_err:
 620         return stor_device;
 621
 622 }
 623
 624 static void handle_sc_creation(struct vmbus_channel *new_sc)
 625 {
 626         struct hv_device *device = new_sc->primary_channel->device_obj;
 627         struct device *dev = &device->device;
 628         struct storvsc_device *stor_device;
 629         struct vmstorage_channel_properties props;
 630         int ret;
 631
 632         stor_device = get_out_stor_device(device);
 633         if (!stor_device)
 634                 return;
 635
 636         memset(&props, 0, sizeof(struct vmstorage_channel_properties));
 637
 638         ret = vmbus_open(new_sc,
 639                          storvsc_ringbuffer_size,
 640                          storvsc_ringbuffer_size,
 641                          (void *)&props,
 642                          sizeof(struct vmstorage_channel_properties),
 643                          storvsc_on_channel_callback, new_sc);
 644
 645         /* In case vmbus_open() fails, we don't use the sub-channel. */
 646         if (ret != 0) {
 647                 dev_err(dev, "Failed to open sub-channel: err=%d\n", ret);
 648                 return;
 649         }
 650
 651         /* Add the sub-channel to the array of available channels. */
 652         stor_device->stor_chns[new_sc->target_cpu] = new_sc;
 653         cpumask_set_cpu(new_sc->target_cpu, &stor_device->alloced_cpus);
 654 }
 655
 656 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
 657 {
 658         struct device *dev = &device->device;
 659         struct storvsc_device *stor_device;
 660         int num_sc;
 661         struct storvsc_cmd_request *request;
 662         struct vstor_packet *vstor_packet;
 663         int ret, t;
 664
 665         /*
 666          * If the number of CPUs is artificially restricted, such as
 667          * with maxcpus=1 on the kernel boot line, Hyper-V could offer
 668          * sub-channels >= the number of CPUs. These sub-channels
 669          * should not be created. The primary channel is already created
 670          * and assigned to one CPU, so check against # CPUs - 1.
 671          */
 672         num_sc = min((int)(num_online_cpus() - 1), max_chns);
 673         if (!num_sc)
 674                 return;
 675
 676         stor_device = get_out_stor_device(device);
 677         if (!stor_device)
 678                 return;
 679
 680         stor_device->num_sc = num_sc;
 681         request = &stor_device->init_request;
 682         vstor_packet = &request->vstor_packet;
 683
 684         /*
 685          * Establish a handler for dealing with subchannels.
 686          */
 687         vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
 688
 689         /*
 690          * Request the host to create sub-channels.
 691          */
 692         memset(request, 0, sizeof(struct storvsc_cmd_request));
 693         init_completion(&request->wait_event);
 694         vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
 695         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 696         vstor_packet->sub_channel_count = num_sc;
 697
 698         ret = vmbus_sendpacket(device->channel, vstor_packet,
 699                                (sizeof(struct vstor_packet) -
 700                                vmscsi_size_delta),
 701                                (unsigned long)request,
 702                                VM_PKT_DATA_INBAND,
 703                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 704
 705         if (ret != 0) {
 706                 dev_err(dev, "Failed to create sub-channel: err=%d\n", ret);
 707                 return;
 708         }
 709
 710         t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
 711         if (t == 0) {
 712                 dev_err(dev, "Failed to create sub-channel: timed out\n");
 713                 return;
 714         }
 715
 716         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
 717             vstor_packet->status != 0) {
 718                 dev_err(dev, "Failed to create sub-channel: op=%d, sts=%d\n",
 719                         vstor_packet->operation, vstor_packet->status);
 720                 return;
 721         }
 722
 723         /*
 724          * We need to do nothing here, because vmbus_process_offer()
 725          * invokes channel->sc_creation_callback, which will open and use
 726          * the sub-channel(s).
 727          */
 728 }
 729
 730 static void cache_wwn(struct storvsc_device *stor_device,
 731                       struct vstor_packet *vstor_packet)
 732 {
 733         /*
 734          * Cache the currently active port and node ww names.
 735          */
 736         if (vstor_packet->wwn_packet.primary_active) {
 737                 stor_device->node_name =
 738                         wwn_to_u64(vstor_packet->wwn_packet.primary_node_wwn);
 739                 stor_device->port_name =
 740                         wwn_to_u64(vstor_packet->wwn_packet.primary_port_wwn);
 741         } else {
 742                 stor_device->node_name =
 743                         wwn_to_u64(vstor_packet->wwn_packet.secondary_node_wwn);
 744                 stor_device->port_name =
 745                         wwn_to_u64(vstor_packet->wwn_packet.secondary_port_wwn);
 746         }
 747 }
 748
 749
 750 static int storvsc_execute_vstor_op(struct hv_device *device,
 751                                     struct storvsc_cmd_request *request,
 752                                     bool status_check)
 753 {
 754         struct vstor_packet *vstor_packet;
 755         int ret, t;
 756
 757         vstor_packet = &request->vstor_packet;
 758
 759         init_completion(&request->wait_event);
 760         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 761
 762         ret = vmbus_sendpacket(device->channel, vstor_packet,
 763                                (sizeof(struct vstor_packet) -
 764                                vmscsi_size_delta),
 765                                (unsigned long)request,
 766                                VM_PKT_DATA_INBAND,
 767                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 768         if (ret != 0)
 769                 return ret;
 770
 771         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
 772         if (t == 0)
 773                 return -ETIMEDOUT;
 774
 775         if (!status_check)
 776                 return ret;
 777
 778         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
 779             vstor_packet->status != 0)
 780                 return -EINVAL;
 781
 782         return ret;
 783 }
 784
 785 static int storvsc_channel_init(struct hv_device *device, bool is_fc)
 786 {
 787         struct storvsc_device *stor_device;
 788         struct storvsc_cmd_request *request;
 789         struct vstor_packet *vstor_packet;
 790         int ret, i;
 791         int max_chns;
 792         bool process_sub_channels = false;
 793
 794         stor_device = get_out_stor_device(device);
 795         if (!stor_device)
 796                 return -ENODEV;
 797
 798         request = &stor_device->init_request;
 799         vstor_packet = &request->vstor_packet;
 800
 801         /*
 802          * Now, initiate the vsc/vsp initialization protocol on the open
 803          * channel
 804          */
 805         memset(request, 0, sizeof(struct storvsc_cmd_request));
 806         vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
 807         ret = storvsc_execute_vstor_op(device, request, true);
 808         if (ret)
 809                 return ret;
 810         /*
 811          * Query host supported protocol version.
 812          */
 813
 814         for (i = 0; i < ARRAY_SIZE(vmstor_protocols); i++) {
 815                 /* reuse the packet for version range supported */
 816                 memset(vstor_packet, 0, sizeof(struct vstor_packet));
 817                 vstor_packet->operation =
 818                         VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
 819
 820                 vstor_packet->version.major_minor =
 821                         vmstor_protocols[i].protocol_version;
 822
 823                 /*
 824                  * The revision number is only used in Windows; set it to 0.
 825                  */
 826                 vstor_packet->version.revision = 0;
 827                 ret = storvsc_execute_vstor_op(device, request, false);
 828                 if (ret != 0)
 829                         return ret;
 830
 831                 if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO)
 832                         return -EINVAL;
 833
 834                 if (vstor_packet->status == 0) {
 835                         vmstor_proto_version =
 836                                 vmstor_protocols[i].protocol_version;
 837
 838                         sense_buffer_size =
 839                                 vmstor_protocols[i].sense_buffer_size;
 840
 841                         vmscsi_size_delta =
 842                                 vmstor_protocols[i].vmscsi_size_delta;
 843
 844                         break;
 845                 }
 846         }
 847
 848         if (vstor_packet->status != 0)
 849                 return -EINVAL;
 850
 851
 852         memset(vstor_packet, 0, sizeof(struct vstor_packet));
 853         vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
 854         ret = storvsc_execute_vstor_op(device, request, true);
 855         if (ret != 0)
 856                 return ret;
 857
 858         /*
 859          * Check to see if multi-channel support is there.
 860          * Hosts that implement protocol version of 5.1 and above
 861          * support multi-channel.
 862          */
 863         max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
 864
 865         /*
 866          * Allocate state to manage the sub-channels.
 867          * We allocate an array based on the numbers of possible CPUs
 868          * (Hyper-V does not support cpu online/offline).
 869          * This Array will be sparseley populated with unique
 870          * channels - primary + sub-channels.
 871          * We will however populate all the slots to evenly distribute
 872          * the load.
 873          */
 874         stor_device->stor_chns = kcalloc(num_possible_cpus(), sizeof(void *),
 875                                          GFP_KERNEL);
 876         if (stor_device->stor_chns == NULL)
 877                 return -ENOMEM;
 878
 879         stor_device->stor_chns[device->channel->target_cpu] = device->channel;
 880         cpumask_set_cpu(device->channel->target_cpu,
 881                         &stor_device->alloced_cpus);
 882
 883         if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN8) {
 884                 if (vstor_packet->storage_channel_properties.flags &
 885                     STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
 886                         process_sub_channels = true;
 887         }
 888         stor_device->max_transfer_bytes =
 889                 vstor_packet->storage_channel_properties.max_transfer_bytes;
 890
 891         if (!is_fc)
 892                 goto done;
 893
 894         /*
 895          * For FC devices retrieve FC HBA data.
 896          */
 897         memset(vstor_packet, 0, sizeof(struct vstor_packet));
 898         vstor_packet->operation = VSTOR_OPERATION_FCHBA_DATA;
 899         ret = storvsc_execute_vstor_op(device, request, true);
 900         if (ret != 0)
 901                 return ret;
 902
 903         /*
 904          * Cache the currently active port and node ww names.
 905          */
 906         cache_wwn(stor_device, vstor_packet);
 907
 908 done:
 909
 910         memset(vstor_packet, 0, sizeof(struct vstor_packet));
 911         vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
 912         ret = storvsc_execute_vstor_op(device, request, true);
 913         if (ret != 0)
 914                 return ret;
 915
 916         if (process_sub_channels)
 917                 handle_multichannel_storage(device, max_chns);
 918
 919         return ret;
 920 }
 921
 922 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
 923                                 struct scsi_cmnd *scmnd,
 924                                 struct Scsi_Host *host,
 925                                 u8 asc, u8 ascq)
 926 {
 927         struct storvsc_scan_work *wrk;
 928         void (*process_err_fn)(struct work_struct *work);
 929         struct hv_host_device *host_dev = shost_priv(host);
 930         bool do_work = false;
 931
 932         switch (SRB_STATUS(vm_srb->srb_status)) {
 933         case SRB_STATUS_ERROR:
 934                 /*
 935                  * Let upper layer deal with error when
 936                  * sense message is present.
 937                  */
 938
 939                 if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID)
 940                         break;
 941                 /*
 942                  * If there is an error; offline the device since all
 943                  * error recovery strategies would have already been
 944                  * deployed on the host side. However, if the command
 945                  * were a pass-through command deal with it appropriately.
 946                  */
 947                 switch (scmnd->cmnd[0]) {
 948                 case ATA_16:
 949                 case ATA_12:
 950                         set_host_byte(scmnd, DID_PASSTHROUGH);
 951                         break;
 952                 /*
 953                  * On Some Windows hosts TEST_UNIT_READY command can return
 954                  * SRB_STATUS_ERROR, let the upper level code deal with it
 955                  * based on the sense information.
 956                  */
 957                 case TEST_UNIT_READY:
 958                         break;
 959                 default:
 960                         set_host_byte(scmnd, DID_ERROR);
 961                 }
 962                 break;
 963         case SRB_STATUS_INVALID_LUN:
 964                 set_host_byte(scmnd, DID_NO_CONNECT);
 965                 do_work = true;
 966                 process_err_fn = storvsc_remove_lun;
 967                 break;
 968         case SRB_STATUS_ABORTED:
 969                 if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID &&
 970                     (asc == 0x2a) && (ascq == 0x9)) {
 971                         do_work = true;
 972                         process_err_fn = storvsc_device_scan;
 973                         /*
 974                          * Retry the I/O that trigerred this.
 975                          */
 976                         set_host_byte(scmnd, DID_REQUEUE);
 977                 }
 978                 break;
 979         }
 980
 981         if (!do_work)
 982                 return;
 983
 984         /*
 985          * We need to schedule work to process this error; schedule it.
 986          */
 987         wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
 988         if (!wrk) {
 989                 set_host_byte(scmnd, DID_TARGET_FAILURE);
 990                 return;
 991         }
 992
 993         wrk->host = host;
 994         wrk->lun = vm_srb->lun;
 995         wrk->tgt_id = vm_srb->target_id;
 996         INIT_WORK(&wrk->work, process_err_fn);
 997         queue_work(host_dev->handle_error_wq, &wrk->work);
 998 }
 999
1000
1001 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request,
1002                                        struct storvsc_device *stor_dev)
1003 {
1004         struct scsi_cmnd *scmnd = cmd_request->cmd;
1005         struct scsi_sense_hdr sense_hdr;
1006         struct vmscsi_request *vm_srb;
1007         u32 data_transfer_length;
1008         struct Scsi_Host *host;
1009         u32 payload_sz = cmd_request->payload_sz;
1010         void *payload = cmd_request->payload;
1011
1012         host = stor_dev->host;
1013
1014         vm_srb = &cmd_request->vstor_packet.vm_srb;
1015         data_transfer_length = vm_srb->data_transfer_length;
1016
1017         scmnd->result = vm_srb->scsi_status;
1018
1019         if (scmnd->result) {
1020                 if (scsi_normalize_sense(scmnd->sense_buffer,
1021                                 SCSI_SENSE_BUFFERSIZE, &sense_hdr) &&
1022                     !(sense_hdr.sense_key == NOT_READY &&
1023                                  sense_hdr.asc == 0x03A) &&
1024                     do_logging(STORVSC_LOGGING_ERROR))
1025                         scsi_print_sense_hdr(scmnd->device, "storvsc",
1026                                              &sense_hdr);
1027         }
1028
1029         if (vm_srb->srb_status != SRB_STATUS_SUCCESS) {
1030                 storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
1031                                          sense_hdr.ascq);
1032                 /*
1033                  * The Windows driver set data_transfer_length on
1034                  * SRB_STATUS_DATA_OVERRUN. On other errors, this value
1035                  * is untouched.  In these cases we set it to 0.
1036                  */
1037                 if (vm_srb->srb_status != SRB_STATUS_DATA_OVERRUN)
1038                         data_transfer_length = 0;
1039         }
1040
1041         scsi_set_resid(scmnd,
1042                 cmd_request->payload->range.len - data_transfer_length);
1043
1044         scmnd->scsi_done(scmnd);
1045
1046         if (payload_sz >
1047                 sizeof(struct vmbus_channel_packet_multipage_buffer))
1048                 kfree(payload);
1049 }
1050
1051 static void storvsc_on_io_completion(struct storvsc_device *stor_device,
1052                                   struct vstor_packet *vstor_packet,
1053                                   struct storvsc_cmd_request *request)
1054 {
1055         struct vstor_packet *stor_pkt;
1056         struct hv_device *device = stor_device->device;
1057
1058         stor_pkt = &request->vstor_packet;
1059
1060         /*
1061          * The current SCSI handling on the host side does
1062          * not correctly handle:
1063          * INQUIRY command with page code parameter set to 0x80
1064          * MODE_SENSE command with cmd[2] == 0x1c
1065          *
1066          * Setup srb and scsi status so this won't be fatal.
1067          * We do this so we can distinguish truly fatal failues
1068          * (srb status == 0x4) and off-line the device in that case.
1069          */
1070
1071         if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1072            (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1073                 vstor_packet->vm_srb.scsi_status = 0;
1074                 vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1075         }
1076
1077
1078         /* Copy over the status...etc */
1079         stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1080         stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1081         stor_pkt->vm_srb.sense_info_length =
1082         vstor_packet->vm_srb.sense_info_length;
1083
1084         if (vstor_packet->vm_srb.scsi_status != 0 ||
1085             vstor_packet->vm_srb.srb_status != SRB_STATUS_SUCCESS)
1086                 storvsc_log(device, STORVSC_LOGGING_WARN,
1087                         "cmd 0x%x scsi status 0x%x srb status 0x%x\n",
1088                         stor_pkt->vm_srb.cdb[0],
1089                         vstor_packet->vm_srb.scsi_status,
1090                         vstor_packet->vm_srb.srb_status);
1091
1092         if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
1093                 /* CHECK_CONDITION */
1094                 if (vstor_packet->vm_srb.srb_status &
1095                         SRB_STATUS_AUTOSENSE_VALID) {
1096                         /* autosense data available */
1097
1098                         storvsc_log(device, STORVSC_LOGGING_WARN,
1099                                 "stor pkt %p autosense data valid - len %d\n",
1100                                 request, vstor_packet->vm_srb.sense_info_length);
1101
1102                         memcpy(request->cmd->sense_buffer,
1103                                vstor_packet->vm_srb.sense_data,
1104                                vstor_packet->vm_srb.sense_info_length);
1105
1106                 }
1107         }
1108
1109         stor_pkt->vm_srb.data_transfer_length =
1110         vstor_packet->vm_srb.data_transfer_length;
1111
1112         storvsc_command_completion(request, stor_device);
1113
1114         if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1115                 stor_device->drain_notify)
1116                 wake_up(&stor_device->waiting_to_drain);
1117
1118
1119 }
1120
1121 static void storvsc_on_receive(struct storvsc_device *stor_device,
1122                              struct vstor_packet *vstor_packet,
1123                              struct storvsc_cmd_request *request)
1124 {
1125         struct hv_host_device *host_dev;
1126         switch (vstor_packet->operation) {
1127         case VSTOR_OPERATION_COMPLETE_IO:
1128                 storvsc_on_io_completion(stor_device, vstor_packet, request);
1129                 break;
1130
1131         case VSTOR_OPERATION_REMOVE_DEVICE:
1132         case VSTOR_OPERATION_ENUMERATE_BUS:
1133                 host_dev = shost_priv(stor_device->host);
1134                 queue_work(
1135                         host_dev->handle_error_wq, &host_dev->host_scan_work);
1136                 break;
1137
1138         case VSTOR_OPERATION_FCHBA_DATA:
1139                 cache_wwn(stor_device, vstor_packet);
1140 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1141                 fc_host_node_name(stor_device->host) = stor_device->node_name;
1142                 fc_host_port_name(stor_device->host) = stor_device->port_name;
1143 #endif
1144                 break;
1145         default:
1146                 break;
1147         }
1148 }
1149
1150 static void storvsc_on_channel_callback(void *context)
1151 {
1152         struct vmbus_channel *channel = (struct vmbus_channel *)context;
1153         const struct vmpacket_descriptor *desc;
1154         struct hv_device *device;
1155         struct storvsc_device *stor_device;
1156
1157         if (channel->primary_channel != NULL)
1158                 device = channel->primary_channel->device_obj;
1159         else
1160                 device = channel->device_obj;
1161
1162         stor_device = get_in_stor_device(device);
1163         if (!stor_device)
1164                 return;
1165
1166         foreach_vmbus_pkt(desc, channel) {
1167                 void *packet = hv_pkt_data(desc);
1168                 struct storvsc_cmd_request *request;
1169
1170                 request = (struct storvsc_cmd_request *)
1171                         ((unsigned long)desc->trans_id);
1172
1173                 if (request == &stor_device->init_request ||
1174                     request == &stor_device->reset_request) {
1175                         memcpy(&request->vstor_packet, packet,
1176                                (sizeof(struct vstor_packet) - vmscsi_size_delta));
1177                         complete(&request->wait_event);
1178                 } else {
1179                         storvsc_on_receive(stor_device, packet, request);
1180                 }
1181         }
1182 }
1183
1184 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size,
1185                                   bool is_fc)
1186 {
1187         struct vmstorage_channel_properties props;
1188         int ret;
1189
1190         memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1191
1192         ret = vmbus_open(device->channel,
1193                          ring_size,
1194                          ring_size,
1195                          (void *)&props,
1196                          sizeof(struct vmstorage_channel_properties),
1197                          storvsc_on_channel_callback, device->channel);
1198
1199         if (ret != 0)
1200                 return ret;
1201
1202         ret = storvsc_channel_init(device, is_fc);
1203
1204         return ret;
1205 }
1206
1207 static int storvsc_dev_remove(struct hv_device *device)
1208 {
1209         struct storvsc_device *stor_device;
1210
1211         stor_device = hv_get_drvdata(device);
1212
1213         stor_device->destroy = true;
1214
1215         /* Make sure flag is set before waiting */
1216         wmb();
1217
1218         /*
1219          * At this point, all outbound traffic should be disable. We
1220          * only allow inbound traffic (responses) to proceed so that
1221          * outstanding requests can be completed.
1222          */
1223
1224         storvsc_wait_to_drain(stor_device);
1225
1226         /*
1227          * Since we have already drained, we don't need to busy wait
1228          * as was done in final_release_stor_device()
1229          * Note that we cannot set the ext pointer to NULL until
1230          * we have drained - to drain the outgoing packets, we need to
1231          * allow incoming packets.
1232          */
1233         hv_set_drvdata(device, NULL);
1234
1235         /* Close the channel */
1236         vmbus_close(device->channel);
1237
1238         kfree(stor_device->stor_chns);
1239         kfree(stor_device);
1240         return 0;
1241 }
1242
1243 static struct vmbus_channel *get_og_chn(struct storvsc_device *stor_device,
1244                                         u16 q_num)
1245 {
1246         u16 slot = 0;
1247         u16 hash_qnum;
1248         const struct cpumask *node_mask;
1249         int num_channels, tgt_cpu;
1250
1251         if (stor_device->num_sc == 0)
1252                 return stor_device->device->channel;
1253
1254         /*
1255          * Our channel array is sparsley populated and we
1256          * initiated I/O on a processor/hw-q that does not
1257          * currently have a designated channel. Fix this.
1258          * The strategy is simple:
1259          * I. Ensure NUMA locality
1260          * II. Distribute evenly (best effort)
1261          * III. Mapping is persistent.
1262          */
1263
1264         node_mask = cpumask_of_node(cpu_to_node(q_num));
1265
1266         num_channels = 0;
1267         for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1268                 if (cpumask_test_cpu(tgt_cpu, node_mask))
1269                         num_channels++;
1270         }
1271         if (num_channels == 0)
1272                 return stor_device->device->channel;
1273
1274         hash_qnum = q_num;
1275         while (hash_qnum >= num_channels)
1276                 hash_qnum -= num_channels;
1277
1278         for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1279                 if (!cpumask_test_cpu(tgt_cpu, node_mask))
1280                         continue;
1281                 if (slot == hash_qnum)
1282                         break;
1283                 slot++;
1284         }
1285
1286         stor_device->stor_chns[q_num] = stor_device->stor_chns[tgt_cpu];
1287
1288         return stor_device->stor_chns[q_num];
1289 }
1290
1291
1292 static int storvsc_do_io(struct hv_device *device,
1293                          struct storvsc_cmd_request *request, u16 q_num)
1294 {
1295         struct storvsc_device *stor_device;
1296         struct vstor_packet *vstor_packet;
1297         struct vmbus_channel *outgoing_channel, *channel;
1298         int ret = 0;
1299         const struct cpumask *node_mask;
1300         int tgt_cpu;
1301
1302         vstor_packet = &request->vstor_packet;
1303         stor_device = get_out_stor_device(device);
1304
1305         if (!stor_device)
1306                 return -ENODEV;
1307
1308
1309         request->device  = device;
1310         /*
1311          * Select an an appropriate channel to send the request out.
1312          */
1313         if (stor_device->stor_chns[q_num] != NULL) {
1314                 outgoing_channel = stor_device->stor_chns[q_num];
1315                 if (outgoing_channel->target_cpu == q_num) {
1316                         /*
1317                          * Ideally, we want to pick a different channel if
1318                          * available on the same NUMA node.
1319                          */
1320                         node_mask = cpumask_of_node(cpu_to_node(q_num));
1321                         for_each_cpu_wrap(tgt_cpu,
1322                                  &stor_device->alloced_cpus, q_num + 1) {
1323                                 if (!cpumask_test_cpu(tgt_cpu, node_mask))
1324                                         continue;
1325                                 if (tgt_cpu == q_num)
1326                                         continue;
1327                                 channel = stor_device->stor_chns[tgt_cpu];
1328                                 if (hv_get_avail_to_write_percent(
1329                                                         &channel->outbound)
1330                                                 > ring_avail_percent_lowater) {
1331                                         outgoing_channel = channel;
1332                                         goto found_channel;
1333                                 }
1334                         }
1335
1336                         /*
1337                          * All the other channels on the same NUMA node are
1338                          * busy. Try to use the channel on the current CPU
1339                          */
1340                         if (hv_get_avail_to_write_percent(
1341                                                 &outgoing_channel->outbound)
1342                                         > ring_avail_percent_lowater)
1343                                 goto found_channel;
1344
1345                         /*
1346                          * If we reach here, all the channels on the current
1347                          * NUMA node are busy. Try to find a channel in
1348                          * other NUMA nodes
1349                          */
1350                         for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1351                                 if (cpumask_test_cpu(tgt_cpu, node_mask))
1352                                         continue;
1353                                 channel = stor_device->stor_chns[tgt_cpu];
1354                                 if (hv_get_avail_to_write_percent(
1355                                                         &channel->outbound)
1356                                                 > ring_avail_percent_lowater) {
1357                                         outgoing_channel = channel;
1358                                         goto found_channel;
1359                                 }
1360                         }
1361                 }
1362         } else {
1363                 outgoing_channel = get_og_chn(stor_device, q_num);
1364         }
1365
1366 found_channel:
1367         vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1368
1369         vstor_packet->vm_srb.length = (sizeof(struct vmscsi_request) -
1370                                         vmscsi_size_delta);
1371
1372
1373         vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1374
1375
1376         vstor_packet->vm_srb.data_transfer_length =
1377         request->payload->range.len;
1378
1379         vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1380
1381         if (request->payload->range.len) {
1382
1383                 ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
1384                                 request->payload, request->payload_sz,
1385                                 vstor_packet,
1386                                 (sizeof(struct vstor_packet) -
1387                                 vmscsi_size_delta),
1388                                 (unsigned long)request);
1389         } else {
1390                 ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
1391                                (sizeof(struct vstor_packet) -
1392                                 vmscsi_size_delta),
1393                                (unsigned long)request,
1394                                VM_PKT_DATA_INBAND,
1395                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1396         }
1397
1398         if (ret != 0)
1399                 return ret;
1400
1401         atomic_inc(&stor_device->num_outstanding_req);
1402
1403         return ret;
1404 }
1405
1406 static int storvsc_device_alloc(struct scsi_device *sdevice)
1407 {
1408         /*
1409          * Set blist flag to permit the reading of the VPD pages even when
1410          * the target may claim SPC-2 compliance. MSFT targets currently
1411          * claim SPC-2 compliance while they implement post SPC-2 features.
1412          * With this flag we can correctly handle WRITE_SAME_16 issues.
1413          *
1414          * Hypervisor reports SCSI_UNKNOWN type for DVD ROM device but
1415          * still supports REPORT LUN.
1416          */
1417         sdevice->sdev_bflags = BLIST_REPORTLUN2 | BLIST_TRY_VPD_PAGES;
1418
1419         return 0;
1420 }
1421
1422 static int storvsc_device_configure(struct scsi_device *sdevice)
1423 {
1424         blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1425
1426         /* Ensure there are no gaps in presented sgls */
1427         blk_queue_virt_boundary(sdevice->request_queue, PAGE_SIZE - 1);
1428
1429         sdevice->no_write_same = 1;
1430
1431         /*
1432          * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
1433          * if the device is a MSFT virtual device.  If the host is
1434          * WIN10 or newer, allow write_same.
1435          */
1436         if (!strncmp(sdevice->vendor, "Msft", 4)) {
1437                 switch (vmstor_proto_version) {
1438                 case VMSTOR_PROTO_VERSION_WIN8:
1439                 case VMSTOR_PROTO_VERSION_WIN8_1:
1440                         sdevice->scsi_level = SCSI_SPC_3;
1441                         break;
1442                 }
1443
1444                 if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN10)
1445                         sdevice->no_write_same = 0;
1446         }
1447
1448         return 0;
1449 }
1450
1451 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1452                            sector_t capacity, int *info)
1453 {
1454         sector_t nsect = capacity;
1455         sector_t cylinders = nsect;
1456         int heads, sectors_pt;
1457
1458         /*
1459          * We are making up these values; let us keep it simple.
1460          */
1461         heads = 0xff;
1462         sectors_pt = 0x3f;      /* Sectors per track */
1463         sector_div(cylinders, heads * sectors_pt);
1464         if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1465                 cylinders = 0xffff;
1466
1467         info[0] = heads;
1468         info[1] = sectors_pt;
1469         info[2] = (int)cylinders;
1470
1471         return 0;
1472 }
1473
1474 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1475 {
1476         struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1477         struct hv_device *device = host_dev->dev;
1478
1479         struct storvsc_device *stor_device;
1480         struct storvsc_cmd_request *request;
1481         struct vstor_packet *vstor_packet;
1482         int ret, t;
1483
1484
1485         stor_device = get_out_stor_device(device);
1486         if (!stor_device)
1487                 return FAILED;
1488
1489         request = &stor_device->reset_request;
1490         vstor_packet = &request->vstor_packet;
1491
1492         init_completion(&request->wait_event);
1493
1494         vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1495         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1496         vstor_packet->vm_srb.path_id = stor_device->path_id;
1497
1498         ret = vmbus_sendpacket(device->channel, vstor_packet,
1499                                (sizeof(struct vstor_packet) -
1500                                 vmscsi_size_delta),
1501                                (unsigned long)&stor_device->reset_request,
1502                                VM_PKT_DATA_INBAND,
1503                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1504         if (ret != 0)
1505                 return FAILED;
1506
1507         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1508         if (t == 0)
1509                 return TIMEOUT_ERROR;
1510
1511
1512         /*
1513          * At this point, all outstanding requests in the adapter
1514          * should have been flushed out and return to us
1515          * There is a potential race here where the host may be in
1516          * the process of responding when we return from here.
1517          * Just wait for all in-transit packets to be accounted for
1518          * before we return from here.
1519          */
1520         storvsc_wait_to_drain(stor_device);
1521
1522         return SUCCESS;
1523 }
1524
1525 /*
1526  * The host guarantees to respond to each command, although I/O latencies might
1527  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1528  * chance to perform EH.
1529  */
1530 static enum blk_eh_timer_return storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1531 {
1532 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1533         if (scmnd->device->host->transportt == fc_transport_template)
1534                 return fc_eh_timed_out(scmnd);
1535 #endif
1536         return BLK_EH_RESET_TIMER;
1537 }
1538
1539 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1540 {
1541         bool allowed = true;
1542         u8 scsi_op = scmnd->cmnd[0];
1543
1544         switch (scsi_op) {
1545         /* the host does not handle WRITE_SAME, log accident usage */
1546         case WRITE_SAME:
1547         /*
1548          * smartd sends this command and the host does not handle
1549          * this. So, don't send it.
1550          */
1551         case SET_WINDOW:
1552                 scmnd->result = ILLEGAL_REQUEST << 16;
1553                 allowed = false;
1554                 break;
1555         default:
1556                 break;
1557         }
1558         return allowed;
1559 }
1560
1561 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1562 {
1563         int ret;
1564         struct hv_host_device *host_dev = shost_priv(host);
1565         struct hv_device *dev = host_dev->dev;
1566         struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
1567         int i;
1568         struct scatterlist *sgl;
1569         unsigned int sg_count = 0;
1570         struct vmscsi_request *vm_srb;
1571         struct scatterlist *cur_sgl;
1572         struct vmbus_packet_mpb_array  *payload;
1573         u32 payload_sz;
1574         u32 length;
1575
1576         if (vmstor_proto_version <= VMSTOR_PROTO_VERSION_WIN8) {
1577                 /*
1578                  * On legacy hosts filter unimplemented commands.
1579                  * Future hosts are expected to correctly handle
1580                  * unsupported commands. Furthermore, it is
1581                  * possible that some of the currently
1582                  * unsupported commands maybe supported in
1583                  * future versions of the host.
1584                  */
1585                 if (!storvsc_scsi_cmd_ok(scmnd)) {
1586                         scmnd->scsi_done(scmnd);
1587                         return 0;
1588                 }
1589         }
1590
1591         /* Setup the cmd request */
1592         cmd_request->cmd = scmnd;
1593
1594         vm_srb = &cmd_request->vstor_packet.vm_srb;
1595         vm_srb->win8_extension.time_out_value = 60;
1596
1597         vm_srb->win8_extension.srb_flags |=
1598                 SRB_FLAGS_DISABLE_SYNCH_TRANSFER;
1599
1600         if (scmnd->device->tagged_supported) {
1601                 vm_srb->win8_extension.srb_flags |=
1602                 (SRB_FLAGS_QUEUE_ACTION_ENABLE | SRB_FLAGS_NO_QUEUE_FREEZE);
1603                 vm_srb->win8_extension.queue_tag = SP_UNTAGGED;
1604                 vm_srb->win8_extension.queue_action = SRB_SIMPLE_TAG_REQUEST;
1605         }
1606
1607         /* Build the SRB */
1608         switch (scmnd->sc_data_direction) {
1609         case DMA_TO_DEVICE:
1610                 vm_srb->data_in = WRITE_TYPE;
1611                 vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_OUT;
1612                 break;
1613         case DMA_FROM_DEVICE:
1614                 vm_srb->data_in = READ_TYPE;
1615                 vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_IN;
1616                 break;
1617         case DMA_NONE:
1618                 vm_srb->data_in = UNKNOWN_TYPE;
1619                 vm_srb->win8_extension.srb_flags |= SRB_FLAGS_NO_DATA_TRANSFER;
1620                 break;
1621         default:
1622                 /*
1623                  * This is DMA_BIDIRECTIONAL or something else we are never
1624                  * supposed to see here.
1625                  */
1626                 WARN(1, "Unexpected data direction: %d\n",
1627                      scmnd->sc_data_direction);
1628                 return -EINVAL;
1629         }
1630
1631
1632         vm_srb->port_number = host_dev->port;
1633         vm_srb->path_id = scmnd->device->channel;
1634         vm_srb->target_id = scmnd->device->id;
1635         vm_srb->lun = scmnd->device->lun;
1636
1637         vm_srb->cdb_length = scmnd->cmd_len;
1638
1639         memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1640
1641         sgl = (struct scatterlist *)scsi_sglist(scmnd);
1642         sg_count = scsi_sg_count(scmnd);
1643
1644         length = scsi_bufflen(scmnd);
1645         payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
1646         payload_sz = sizeof(cmd_request->mpb);
1647
1648         if (sg_count) {
1649                 if (sg_count > MAX_PAGE_BUFFER_COUNT) {
1650
1651                         payload_sz = (sg_count * sizeof(u64) +
1652                                       sizeof(struct vmbus_packet_mpb_array));
1653                         payload = kzalloc(payload_sz, GFP_ATOMIC);
1654                         if (!payload)
1655                                 return SCSI_MLQUEUE_DEVICE_BUSY;
1656                 }
1657
1658                 payload->range.len = length;
1659                 payload->range.offset = sgl[0].offset;
1660
1661                 cur_sgl = sgl;
1662                 for (i = 0; i < sg_count; i++) {
1663                         payload->range.pfn_array[i] =
1664                                 page_to_pfn(sg_page((cur_sgl)));
1665                         cur_sgl = sg_next(cur_sgl);
1666                 }
1667         }
1668
1669         cmd_request->payload = payload;
1670         cmd_request->payload_sz = payload_sz;
1671
1672         /* Invokes the vsc to start an IO */
1673         ret = storvsc_do_io(dev, cmd_request, get_cpu());
1674         put_cpu();
1675
1676         if (ret == -EAGAIN) {
1677                 if (payload_sz > sizeof(cmd_request->mpb))
1678                         kfree(payload);
1679                 /* no more space */
1680                 return SCSI_MLQUEUE_DEVICE_BUSY;
1681         }
1682
1683         return 0;
1684 }
1685
1686 static struct scsi_host_template scsi_driver = {
1687         .module =               THIS_MODULE,
1688         .name =                 "storvsc_host_t",
1689         .cmd_size =             sizeof(struct storvsc_cmd_request),
1690         .bios_param =           storvsc_get_chs,
1691         .queuecommand =         storvsc_queuecommand,
1692         .eh_host_reset_handler =        storvsc_host_reset_handler,
1693         .proc_name =            "storvsc_host",
1694         .eh_timed_out =         storvsc_eh_timed_out,
1695         .slave_alloc =          storvsc_device_alloc,
1696         .slave_configure =      storvsc_device_configure,
1697         .cmd_per_lun =          2048,
1698         .this_id =              -1,
1699         /* Make sure we dont get a sg segment crosses a page boundary */
1700         .dma_boundary =         PAGE_SIZE-1,
1701         .no_write_same =        1,
1702         .track_queue_depth =    1,
1703         .change_queue_depth =   storvsc_change_queue_depth,
1704 };
1705
1706 enum {
1707         SCSI_GUID,
1708         IDE_GUID,
1709         SFC_GUID,
1710 };
1711
1712 static const struct hv_vmbus_device_id id_table[] = {
1713         /* SCSI guid */
1714         { HV_SCSI_GUID,
1715           .driver_data = SCSI_GUID
1716         },
1717         /* IDE guid */
1718         { HV_IDE_GUID,
1719           .driver_data = IDE_GUID
1720         },
1721         /* Fibre Channel GUID */
1722         {
1723           HV_SYNTHFC_GUID,
1724           .driver_data = SFC_GUID
1725         },
1726         { },
1727 };
1728
1729 MODULE_DEVICE_TABLE(vmbus, id_table);
1730
1731 static int storvsc_probe(struct hv_device *device,
1732                         const struct hv_vmbus_device_id *dev_id)
1733 {
1734         int ret;
1735         int num_cpus = num_online_cpus();
1736         struct Scsi_Host *host;
1737         struct hv_host_device *host_dev;
1738         bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1739         bool is_fc = ((dev_id->driver_data == SFC_GUID) ? true : false);
1740         int target = 0;
1741         struct storvsc_device *stor_device;
1742         int max_luns_per_target;
1743         int max_targets;
1744         int max_channels;
1745         int max_sub_channels = 0;
1746
1747         /*
1748          * Based on the windows host we are running on,
1749          * set state to properly communicate with the host.
1750          */
1751
1752         if (vmbus_proto_version < VERSION_WIN8) {
1753                 max_luns_per_target = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1754                 max_targets = STORVSC_IDE_MAX_TARGETS;
1755                 max_channels = STORVSC_IDE_MAX_CHANNELS;
1756         } else {
1757                 max_luns_per_target = STORVSC_MAX_LUNS_PER_TARGET;
1758                 max_targets = STORVSC_MAX_TARGETS;
1759                 max_channels = STORVSC_MAX_CHANNELS;
1760                 /*
1761                  * On Windows8 and above, we support sub-channels for storage
1762                  * on SCSI and FC controllers.
1763                  * The number of sub-channels offerred is based on the number of
1764                  * VCPUs in the guest.
1765                  */
1766                 if (!dev_is_ide)
1767                         max_sub_channels =
1768                                 (num_cpus - 1) / storvsc_vcpus_per_sub_channel;
1769         }
1770
1771         scsi_driver.can_queue = max_outstanding_req_per_channel *
1772                                 (max_sub_channels + 1) *
1773                                 (100 - ring_avail_percent_lowater) / 100;
1774
1775         host = scsi_host_alloc(&scsi_driver,
1776                                sizeof(struct hv_host_device));
1777         if (!host)
1778                 return -ENOMEM;
1779
1780         host_dev = shost_priv(host);
1781         memset(host_dev, 0, sizeof(struct hv_host_device));
1782
1783         host_dev->port = host->host_no;
1784         host_dev->dev = device;
1785         host_dev->host = host;
1786
1787
1788         stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1789         if (!stor_device) {
1790                 ret = -ENOMEM;
1791                 goto err_out0;
1792         }
1793
1794         stor_device->destroy = false;
1795         init_waitqueue_head(&stor_device->waiting_to_drain);
1796         stor_device->device = device;
1797         stor_device->host = host;
1798         hv_set_drvdata(device, stor_device);
1799
1800         stor_device->port_number = host->host_no;
1801         ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size, is_fc);
1802         if (ret)
1803                 goto err_out1;
1804
1805         host_dev->path = stor_device->path_id;
1806         host_dev->target = stor_device->target_id;
1807
1808         switch (dev_id->driver_data) {
1809         case SFC_GUID:
1810                 host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
1811                 host->max_id = STORVSC_FC_MAX_TARGETS;
1812                 host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
1813 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1814                 host->transportt = fc_transport_template;
1815 #endif
1816                 break;
1817
1818         case SCSI_GUID:
1819                 host->max_lun = max_luns_per_target;
1820                 host->max_id = max_targets;
1821                 host->max_channel = max_channels - 1;
1822                 break;
1823
1824         default:
1825                 host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1826                 host->max_id = STORVSC_IDE_MAX_TARGETS;
1827                 host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
1828                 break;
1829         }
1830         /* max cmd length */
1831         host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1832
1833         /*
1834          * set the table size based on the info we got
1835          * from the host.
1836          */
1837         host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT);
1838         /*
1839          * Set the number of HW queues we are supporting.
1840          */
1841         if (stor_device->num_sc != 0)
1842                 host->nr_hw_queues = stor_device->num_sc + 1;
1843
1844         /*
1845          * Set the error handler work queue.
1846          */
1847         host_dev->handle_error_wq =
1848                         alloc_ordered_workqueue("storvsc_error_wq_%d",
1849                                                 WQ_MEM_RECLAIM,
1850                                                 host->host_no);
1851         if (!host_dev->handle_error_wq)
1852                 goto err_out2;
1853         INIT_WORK(&host_dev->host_scan_work, storvsc_host_scan);
1854         /* Register the HBA and start the scsi bus scan */
1855         ret = scsi_add_host(host, &device->device);
1856         if (ret != 0)
1857                 goto err_out3;
1858
1859         if (!dev_is_ide) {
1860                 scsi_scan_host(host);
1861         } else {
1862                 target = (device->dev_instance.b[5] << 8 |
1863                          device->dev_instance.b[4]);
1864                 ret = scsi_add_device(host, 0, target, 0);
1865                 if (ret)
1866                         goto err_out4;
1867         }
1868 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1869         if (host->transportt == fc_transport_template) {
1870                 struct fc_rport_identifiers ids = {
1871                         .roles = FC_PORT_ROLE_FCP_DUMMY_INITIATOR,
1872                 };
1873
1874                 fc_host_node_name(host) = stor_device->node_name;
1875                 fc_host_port_name(host) = stor_device->port_name;
1876                 stor_device->rport = fc_remote_port_add(host, 0, &ids);
1877                 if (!stor_device->rport) {
1878                         ret = -ENOMEM;
1879                         goto err_out4;
1880                 }
1881         }
1882 #endif
1883         return 0;
1884
1885 err_out4:
1886         scsi_remove_host(host);
1887
1888 err_out3:
1889         destroy_workqueue(host_dev->handle_error_wq);
1890
1891 err_out2:
1892         /*
1893          * Once we have connected with the host, we would need to
1894          * to invoke storvsc_dev_remove() to rollback this state and
1895          * this call also frees up the stor_device; hence the jump around
1896          * err_out1 label.
1897          */
1898         storvsc_dev_remove(device);
1899         goto err_out0;
1900
1901 err_out1:
1902         kfree(stor_device->stor_chns);
1903         kfree(stor_device);
1904
1905 err_out0:
1906         scsi_host_put(host);
1907         return ret;
1908 }
1909
1910 /* Change a scsi target's queue depth */
1911 static int storvsc_change_queue_depth(struct scsi_device *sdev, int queue_depth)
1912 {
1913         if (queue_depth > scsi_driver.can_queue)
1914                 queue_depth = scsi_driver.can_queue;
1915
1916         return scsi_change_queue_depth(sdev, queue_depth);
1917 }
1918
1919 static int storvsc_remove(struct hv_device *dev)
1920 {
1921         struct storvsc_device *stor_device = hv_get_drvdata(dev);
1922         struct Scsi_Host *host = stor_device->host;
1923         struct hv_host_device *host_dev = shost_priv(host);
1924
1925 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1926         if (host->transportt == fc_transport_template) {
1927                 fc_remote_port_delete(stor_device->rport);
1928                 fc_remove_host(host);
1929         }
1930 #endif
1931         destroy_workqueue(host_dev->handle_error_wq);
1932         scsi_remove_host(host);
1933         storvsc_dev_remove(dev);
1934         scsi_host_put(host);
1935
1936         return 0;
1937 }
1938
1939 static struct hv_driver storvsc_drv = {
1940         .name = KBUILD_MODNAME,
1941         .id_table = id_table,
1942         .probe = storvsc_probe,
1943         .remove = storvsc_remove,
1944         .driver = {
1945                 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
1946         },
1947 };
1948
1949 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1950 static struct fc_function_template fc_transport_functions = {
1951         .show_host_node_name = 1,
1952         .show_host_port_name = 1,
1953 };
1954 #endif
1955
1956 static int __init storvsc_drv_init(void)
1957 {
1958         int ret;
1959
1960         /*
1961          * Divide the ring buffer data size (which is 1 page less
1962          * than the ring buffer size since that page is reserved for
1963          * the ring buffer indices) by the max request size (which is
1964          * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
1965          */
1966         max_outstanding_req_per_channel =
1967                 ((storvsc_ringbuffer_size - PAGE_SIZE) /
1968                 ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
1969                 sizeof(struct vstor_packet) + sizeof(u64) -
1970                 vmscsi_size_delta,
1971                 sizeof(u64)));
1972
1973 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1974         fc_transport_template = fc_attach_transport(&fc_transport_functions);
1975         if (!fc_transport_template)
1976                 return -ENODEV;
1977 #endif
1978
1979         ret = vmbus_driver_register(&storvsc_drv);
1980
1981 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1982         if (ret)
1983                 fc_release_transport(fc_transport_template);
1984 #endif
1985
1986         return ret;
1987 }
1988
1989 static void __exit storvsc_drv_exit(void)
1990 {
1991         vmbus_driver_unregister(&storvsc_drv);
1992 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1993         fc_release_transport(fc_transport_template);
1994 #endif
1995 }
1996
1997 MODULE_LICENSE("GPL");
1998 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
1999 module_init(storvsc_drv_init);
2000 module_exit(storvsc_drv_exit);