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 struct scsi_host_template scsi_driver;
 403 static void storvsc_on_channel_callback(void *context);
 404
 405 #define STORVSC_MAX_LUNS_PER_TARGET                     255
 406 #define STORVSC_MAX_TARGETS                             2
 407 #define STORVSC_MAX_CHANNELS                            8
 408
 409 #define STORVSC_FC_MAX_LUNS_PER_TARGET                  255
 410 #define STORVSC_FC_MAX_TARGETS                          128
 411 #define STORVSC_FC_MAX_CHANNELS                         8
 412
 413 #define STORVSC_IDE_MAX_LUNS_PER_TARGET                 64
 414 #define STORVSC_IDE_MAX_TARGETS                         1
 415 #define STORVSC_IDE_MAX_CHANNELS                        1
 416
 417 struct storvsc_cmd_request {
 418         struct scsi_cmnd *cmd;
 419
 420         struct hv_device *device;
 421
 422         /* Synchronize the request/response if needed */
 423         struct completion wait_event;
 424
 425         struct vmbus_channel_packet_multipage_buffer mpb;
 426         struct vmbus_packet_mpb_array *payload;
 427         u32 payload_sz;
 428
 429         struct vstor_packet vstor_packet;
 430 };
 431
 432
 433 /* A storvsc device is a device object that contains a vmbus channel */
 434 struct storvsc_device {
 435         struct hv_device *device;
 436
 437         bool     destroy;
 438         bool     drain_notify;
 439         atomic_t num_outstanding_req;
 440         struct Scsi_Host *host;
 441
 442         wait_queue_head_t waiting_to_drain;
 443
 444         /*
 445          * Each unique Port/Path/Target represents 1 channel ie scsi
 446          * controller. In reality, the pathid, targetid is always 0
 447          * and the port is set by us
 448          */
 449         unsigned int port_number;
 450         unsigned char path_id;
 451         unsigned char target_id;
 452
 453         /*
 454          * Max I/O, the device can support.
 455          */
 456         u32   max_transfer_bytes;
 457         /*
 458          * Number of sub-channels we will open.
 459          */
 460         u16 num_sc;
 461         struct vmbus_channel **stor_chns;
 462         /*
 463          * Mask of CPUs bound to subchannels.
 464          */
 465         struct cpumask alloced_cpus;
 466         /*
 467          * Serializes modifications of stor_chns[] from storvsc_do_io()
 468          * and storvsc_change_target_cpu().
 469          */
 470         spinlock_t lock;
 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 storvsc_change_target_cpu(struct vmbus_channel *channel, u32 old,
 631                                       u32 new)
 632 {
 633         struct storvsc_device *stor_device;
 634         struct vmbus_channel *cur_chn;
 635         bool old_is_alloced = false;
 636         struct hv_device *device;
 637         unsigned long flags;
 638         int cpu;
 639
 640         device = channel->primary_channel ?
 641                         channel->primary_channel->device_obj
 642                                 : channel->device_obj;
 643         stor_device = get_out_stor_device(device);
 644         if (!stor_device)
 645                 return;
 646
 647         /* See storvsc_do_io() -> get_og_chn(). */
 648         spin_lock_irqsave(&stor_device->lock, flags);
 649
 650         /*
 651          * Determines if the storvsc device has other channels assigned to
 652          * the "old" CPU to update the alloced_cpus mask and the stor_chns
 653          * array.
 654          */
 655         if (device->channel != channel && device->channel->target_cpu == old) {
 656                 cur_chn = device->channel;
 657                 old_is_alloced = true;
 658                 goto old_is_alloced;
 659         }
 660         list_for_each_entry(cur_chn, &device->channel->sc_list, sc_list) {
 661                 if (cur_chn == channel)
 662                         continue;
 663                 if (cur_chn->target_cpu == old) {
 664                         old_is_alloced = true;
 665                         goto old_is_alloced;
 666                 }
 667         }
 668
 669 old_is_alloced:
 670         if (old_is_alloced)
 671                 WRITE_ONCE(stor_device->stor_chns[old], cur_chn);
 672         else
 673                 cpumask_clear_cpu(old, &stor_device->alloced_cpus);
 674
 675         /* "Flush" the stor_chns array. */
 676         for_each_possible_cpu(cpu) {
 677                 if (stor_device->stor_chns[cpu] && !cpumask_test_cpu(
 678                                         cpu, &stor_device->alloced_cpus))
 679                         WRITE_ONCE(stor_device->stor_chns[cpu], NULL);
 680         }
 681
 682         WRITE_ONCE(stor_device->stor_chns[new], channel);
 683         cpumask_set_cpu(new, &stor_device->alloced_cpus);
 684
 685         spin_unlock_irqrestore(&stor_device->lock, flags);
 686 }
 687
 688 static void handle_sc_creation(struct vmbus_channel *new_sc)
 689 {
 690         struct hv_device *device = new_sc->primary_channel->device_obj;
 691         struct device *dev = &device->device;
 692         struct storvsc_device *stor_device;
 693         struct vmstorage_channel_properties props;
 694         int ret;
 695
 696         stor_device = get_out_stor_device(device);
 697         if (!stor_device)
 698                 return;
 699
 700         memset(&props, 0, sizeof(struct vmstorage_channel_properties));
 701
 702         /*
 703          * The size of vmbus_requestor is an upper bound on the number of requests
 704          * that can be in-progress at any one time across all channels.
 705          */
 706         new_sc->rqstor_size = scsi_driver.can_queue;
 707
 708         ret = vmbus_open(new_sc,
 709                          storvsc_ringbuffer_size,
 710                          storvsc_ringbuffer_size,
 711                          (void *)&props,
 712                          sizeof(struct vmstorage_channel_properties),
 713                          storvsc_on_channel_callback, new_sc);
 714
 715         /* In case vmbus_open() fails, we don't use the sub-channel. */
 716         if (ret != 0) {
 717                 dev_err(dev, "Failed to open sub-channel: err=%d\n", ret);
 718                 return;
 719         }
 720
 721         new_sc->change_target_cpu_callback = storvsc_change_target_cpu;
 722
 723         /* Add the sub-channel to the array of available channels. */
 724         stor_device->stor_chns[new_sc->target_cpu] = new_sc;
 725         cpumask_set_cpu(new_sc->target_cpu, &stor_device->alloced_cpus);
 726 }
 727
 728 static void  handle_multichannel_storage(struct hv_device *device, int max_chns)
 729 {
 730         struct device *dev = &device->device;
 731         struct storvsc_device *stor_device;
 732         int num_sc;
 733         struct storvsc_cmd_request *request;
 734         struct vstor_packet *vstor_packet;
 735         int ret, t;
 736
 737         /*
 738          * If the number of CPUs is artificially restricted, such as
 739          * with maxcpus=1 on the kernel boot line, Hyper-V could offer
 740          * sub-channels >= the number of CPUs. These sub-channels
 741          * should not be created. The primary channel is already created
 742          * and assigned to one CPU, so check against # CPUs - 1.
 743          */
 744         num_sc = min((int)(num_online_cpus() - 1), max_chns);
 745         if (!num_sc)
 746                 return;
 747
 748         stor_device = get_out_stor_device(device);
 749         if (!stor_device)
 750                 return;
 751
 752         stor_device->num_sc = num_sc;
 753         request = &stor_device->init_request;
 754         vstor_packet = &request->vstor_packet;
 755
 756         /*
 757          * Establish a handler for dealing with subchannels.
 758          */
 759         vmbus_set_sc_create_callback(device->channel, handle_sc_creation);
 760
 761         /*
 762          * Request the host to create sub-channels.
 763          */
 764         memset(request, 0, sizeof(struct storvsc_cmd_request));
 765         init_completion(&request->wait_event);
 766         vstor_packet->operation = VSTOR_OPERATION_CREATE_SUB_CHANNELS;
 767         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 768         vstor_packet->sub_channel_count = num_sc;
 769
 770         ret = vmbus_sendpacket(device->channel, vstor_packet,
 771                                (sizeof(struct vstor_packet) -
 772                                vmscsi_size_delta),
 773                                (unsigned long)request,
 774                                VM_PKT_DATA_INBAND,
 775                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 776
 777         if (ret != 0) {
 778                 dev_err(dev, "Failed to create sub-channel: err=%d\n", ret);
 779                 return;
 780         }
 781
 782         t = wait_for_completion_timeout(&request->wait_event, 10*HZ);
 783         if (t == 0) {
 784                 dev_err(dev, "Failed to create sub-channel: timed out\n");
 785                 return;
 786         }
 787
 788         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
 789             vstor_packet->status != 0) {
 790                 dev_err(dev, "Failed to create sub-channel: op=%d, sts=%d\n",
 791                         vstor_packet->operation, vstor_packet->status);
 792                 return;
 793         }
 794
 795         /*
 796          * We need to do nothing here, because vmbus_process_offer()
 797          * invokes channel->sc_creation_callback, which will open and use
 798          * the sub-channel(s).
 799          */
 800 }
 801
 802 static void cache_wwn(struct storvsc_device *stor_device,
 803                       struct vstor_packet *vstor_packet)
 804 {
 805         /*
 806          * Cache the currently active port and node ww names.
 807          */
 808         if (vstor_packet->wwn_packet.primary_active) {
 809                 stor_device->node_name =
 810                         wwn_to_u64(vstor_packet->wwn_packet.primary_node_wwn);
 811                 stor_device->port_name =
 812                         wwn_to_u64(vstor_packet->wwn_packet.primary_port_wwn);
 813         } else {
 814                 stor_device->node_name =
 815                         wwn_to_u64(vstor_packet->wwn_packet.secondary_node_wwn);
 816                 stor_device->port_name =
 817                         wwn_to_u64(vstor_packet->wwn_packet.secondary_port_wwn);
 818         }
 819 }
 820
 821
 822 static int storvsc_execute_vstor_op(struct hv_device *device,
 823                                     struct storvsc_cmd_request *request,
 824                                     bool status_check)
 825 {
 826         struct vstor_packet *vstor_packet;
 827         int ret, t;
 828
 829         vstor_packet = &request->vstor_packet;
 830
 831         init_completion(&request->wait_event);
 832         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 833
 834         ret = vmbus_sendpacket(device->channel, vstor_packet,
 835                                (sizeof(struct vstor_packet) -
 836                                vmscsi_size_delta),
 837                                (unsigned long)request,
 838                                VM_PKT_DATA_INBAND,
 839                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 840         if (ret != 0)
 841                 return ret;
 842
 843         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
 844         if (t == 0)
 845                 return -ETIMEDOUT;
 846
 847         if (!status_check)
 848                 return ret;
 849
 850         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
 851             vstor_packet->status != 0)
 852                 return -EINVAL;
 853
 854         return ret;
 855 }
 856
 857 static int storvsc_channel_init(struct hv_device *device, bool is_fc)
 858 {
 859         struct storvsc_device *stor_device;
 860         struct storvsc_cmd_request *request;
 861         struct vstor_packet *vstor_packet;
 862         int ret, i;
 863         int max_chns;
 864         bool process_sub_channels = false;
 865
 866         stor_device = get_out_stor_device(device);
 867         if (!stor_device)
 868                 return -ENODEV;
 869
 870         request = &stor_device->init_request;
 871         vstor_packet = &request->vstor_packet;
 872
 873         /*
 874          * Now, initiate the vsc/vsp initialization protocol on the open
 875          * channel
 876          */
 877         memset(request, 0, sizeof(struct storvsc_cmd_request));
 878         vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
 879         ret = storvsc_execute_vstor_op(device, request, true);
 880         if (ret)
 881                 return ret;
 882         /*
 883          * Query host supported protocol version.
 884          */
 885
 886         for (i = 0; i < ARRAY_SIZE(vmstor_protocols); i++) {
 887                 /* reuse the packet for version range supported */
 888                 memset(vstor_packet, 0, sizeof(struct vstor_packet));
 889                 vstor_packet->operation =
 890                         VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
 891
 892                 vstor_packet->version.major_minor =
 893                         vmstor_protocols[i].protocol_version;
 894
 895                 /*
 896                  * The revision number is only used in Windows; set it to 0.
 897                  */
 898                 vstor_packet->version.revision = 0;
 899                 ret = storvsc_execute_vstor_op(device, request, false);
 900                 if (ret != 0)
 901                         return ret;
 902
 903                 if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO)
 904                         return -EINVAL;
 905
 906                 if (vstor_packet->status == 0) {
 907                         vmstor_proto_version =
 908                                 vmstor_protocols[i].protocol_version;
 909
 910                         sense_buffer_size =
 911                                 vmstor_protocols[i].sense_buffer_size;
 912
 913                         vmscsi_size_delta =
 914                                 vmstor_protocols[i].vmscsi_size_delta;
 915
 916                         break;
 917                 }
 918         }
 919
 920         if (vstor_packet->status != 0)
 921                 return -EINVAL;
 922
 923
 924         memset(vstor_packet, 0, sizeof(struct vstor_packet));
 925         vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
 926         ret = storvsc_execute_vstor_op(device, request, true);
 927         if (ret != 0)
 928                 return ret;
 929
 930         /*
 931          * Check to see if multi-channel support is there.
 932          * Hosts that implement protocol version of 5.1 and above
 933          * support multi-channel.
 934          */
 935         max_chns = vstor_packet->storage_channel_properties.max_channel_cnt;
 936
 937         /*
 938          * Allocate state to manage the sub-channels.
 939          * We allocate an array based on the numbers of possible CPUs
 940          * (Hyper-V does not support cpu online/offline).
 941          * This Array will be sparseley populated with unique
 942          * channels - primary + sub-channels.
 943          * We will however populate all the slots to evenly distribute
 944          * the load.
 945          */
 946         stor_device->stor_chns = kcalloc(num_possible_cpus(), sizeof(void *),
 947                                          GFP_KERNEL);
 948         if (stor_device->stor_chns == NULL)
 949                 return -ENOMEM;
 950
 951         device->channel->change_target_cpu_callback = storvsc_change_target_cpu;
 952
 953         stor_device->stor_chns[device->channel->target_cpu] = device->channel;
 954         cpumask_set_cpu(device->channel->target_cpu,
 955                         &stor_device->alloced_cpus);
 956
 957         if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN8) {
 958                 if (vstor_packet->storage_channel_properties.flags &
 959                     STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL)
 960                         process_sub_channels = true;
 961         }
 962         stor_device->max_transfer_bytes =
 963                 vstor_packet->storage_channel_properties.max_transfer_bytes;
 964
 965         if (!is_fc)
 966                 goto done;
 967
 968         /*
 969          * For FC devices retrieve FC HBA data.
 970          */
 971         memset(vstor_packet, 0, sizeof(struct vstor_packet));
 972         vstor_packet->operation = VSTOR_OPERATION_FCHBA_DATA;
 973         ret = storvsc_execute_vstor_op(device, request, true);
 974         if (ret != 0)
 975                 return ret;
 976
 977         /*
 978          * Cache the currently active port and node ww names.
 979          */
 980         cache_wwn(stor_device, vstor_packet);
 981
 982 done:
 983
 984         memset(vstor_packet, 0, sizeof(struct vstor_packet));
 985         vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
 986         ret = storvsc_execute_vstor_op(device, request, true);
 987         if (ret != 0)
 988                 return ret;
 989
 990         if (process_sub_channels)
 991                 handle_multichannel_storage(device, max_chns);
 992
 993         return ret;
 994 }
 995
 996 static void storvsc_handle_error(struct vmscsi_request *vm_srb,
 997                                 struct scsi_cmnd *scmnd,
 998                                 struct Scsi_Host *host,
 999                                 u8 asc, u8 ascq)
1000 {
1001         struct storvsc_scan_work *wrk;
1002         void (*process_err_fn)(struct work_struct *work);
1003         struct hv_host_device *host_dev = shost_priv(host);
1004         bool do_work = false;
1005
1006         switch (SRB_STATUS(vm_srb->srb_status)) {
1007         case SRB_STATUS_ERROR:
1008                 /*
1009                  * Let upper layer deal with error when
1010                  * sense message is present.
1011                  */
1012
1013                 if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID)
1014                         break;
1015                 /*
1016                  * If there is an error; offline the device since all
1017                  * error recovery strategies would have already been
1018                  * deployed on the host side. However, if the command
1019                  * were a pass-through command deal with it appropriately.
1020                  */
1021                 switch (scmnd->cmnd[0]) {
1022                 case ATA_16:
1023                 case ATA_12:
1024                         set_host_byte(scmnd, DID_PASSTHROUGH);
1025                         break;
1026                 /*
1027                  * On Some Windows hosts TEST_UNIT_READY command can return
1028                  * SRB_STATUS_ERROR, let the upper level code deal with it
1029                  * based on the sense information.
1030                  */
1031                 case TEST_UNIT_READY:
1032                         break;
1033                 default:
1034                         set_host_byte(scmnd, DID_ERROR);
1035                 }
1036                 break;
1037         case SRB_STATUS_INVALID_LUN:
1038                 set_host_byte(scmnd, DID_NO_CONNECT);
1039                 do_work = true;
1040                 process_err_fn = storvsc_remove_lun;
1041                 break;
1042         case SRB_STATUS_ABORTED:
1043                 if (vm_srb->srb_status & SRB_STATUS_AUTOSENSE_VALID &&
1044                     (asc == 0x2a) && (ascq == 0x9)) {
1045                         do_work = true;
1046                         process_err_fn = storvsc_device_scan;
1047                         /*
1048                          * Retry the I/O that triggered this.
1049                          */
1050                         set_host_byte(scmnd, DID_REQUEUE);
1051                 }
1052                 break;
1053         }
1054
1055         if (!do_work)
1056                 return;
1057
1058         /*
1059          * We need to schedule work to process this error; schedule it.
1060          */
1061         wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
1062         if (!wrk) {
1063                 set_host_byte(scmnd, DID_TARGET_FAILURE);
1064                 return;
1065         }
1066
1067         wrk->host = host;
1068         wrk->lun = vm_srb->lun;
1069         wrk->tgt_id = vm_srb->target_id;
1070         INIT_WORK(&wrk->work, process_err_fn);
1071         queue_work(host_dev->handle_error_wq, &wrk->work);
1072 }
1073
1074
1075 static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request,
1076                                        struct storvsc_device *stor_dev)
1077 {
1078         struct scsi_cmnd *scmnd = cmd_request->cmd;
1079         struct scsi_sense_hdr sense_hdr;
1080         struct vmscsi_request *vm_srb;
1081         u32 data_transfer_length;
1082         struct Scsi_Host *host;
1083         u32 payload_sz = cmd_request->payload_sz;
1084         void *payload = cmd_request->payload;
1085
1086         host = stor_dev->host;
1087
1088         vm_srb = &cmd_request->vstor_packet.vm_srb;
1089         data_transfer_length = vm_srb->data_transfer_length;
1090
1091         scmnd->result = vm_srb->scsi_status;
1092
1093         if (scmnd->result) {
1094                 if (scsi_normalize_sense(scmnd->sense_buffer,
1095                                 SCSI_SENSE_BUFFERSIZE, &sense_hdr) &&
1096                     !(sense_hdr.sense_key == NOT_READY &&
1097                                  sense_hdr.asc == 0x03A) &&
1098                     do_logging(STORVSC_LOGGING_ERROR))
1099                         scsi_print_sense_hdr(scmnd->device, "storvsc",
1100                                              &sense_hdr);
1101         }
1102
1103         if (vm_srb->srb_status != SRB_STATUS_SUCCESS) {
1104                 storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
1105                                          sense_hdr.ascq);
1106                 /*
1107                  * The Windows driver set data_transfer_length on
1108                  * SRB_STATUS_DATA_OVERRUN. On other errors, this value
1109                  * is untouched.  In these cases we set it to 0.
1110                  */
1111                 if (vm_srb->srb_status != SRB_STATUS_DATA_OVERRUN)
1112                         data_transfer_length = 0;
1113         }
1114
1115         /* Validate data_transfer_length (from Hyper-V) */
1116         if (data_transfer_length > cmd_request->payload->range.len)
1117                 data_transfer_length = cmd_request->payload->range.len;
1118
1119         scsi_set_resid(scmnd,
1120                 cmd_request->payload->range.len - data_transfer_length);
1121
1122         scmnd->scsi_done(scmnd);
1123
1124         if (payload_sz >
1125                 sizeof(struct vmbus_channel_packet_multipage_buffer))
1126                 kfree(payload);
1127 }
1128
1129 static void storvsc_on_io_completion(struct storvsc_device *stor_device,
1130                                   struct vstor_packet *vstor_packet,
1131                                   struct storvsc_cmd_request *request)
1132 {
1133         struct vstor_packet *stor_pkt;
1134         struct hv_device *device = stor_device->device;
1135
1136         stor_pkt = &request->vstor_packet;
1137
1138         /*
1139          * The current SCSI handling on the host side does
1140          * not correctly handle:
1141          * INQUIRY command with page code parameter set to 0x80
1142          * MODE_SENSE command with cmd[2] == 0x1c
1143          *
1144          * Setup srb and scsi status so this won't be fatal.
1145          * We do this so we can distinguish truly fatal failues
1146          * (srb status == 0x4) and off-line the device in that case.
1147          */
1148
1149         if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
1150            (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
1151                 vstor_packet->vm_srb.scsi_status = 0;
1152                 vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
1153         }
1154
1155
1156         /* Copy over the status...etc */
1157         stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
1158         stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
1159
1160         /* Validate sense_info_length (from Hyper-V) */
1161         if (vstor_packet->vm_srb.sense_info_length > sense_buffer_size)
1162                 vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1163
1164         stor_pkt->vm_srb.sense_info_length =
1165         vstor_packet->vm_srb.sense_info_length;
1166
1167         if (vstor_packet->vm_srb.scsi_status != 0 ||
1168             vstor_packet->vm_srb.srb_status != SRB_STATUS_SUCCESS)
1169                 storvsc_log(device, STORVSC_LOGGING_WARN,
1170                         "cmd 0x%x scsi status 0x%x srb status 0x%x\n",
1171                         stor_pkt->vm_srb.cdb[0],
1172                         vstor_packet->vm_srb.scsi_status,
1173                         vstor_packet->vm_srb.srb_status);
1174
1175         if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
1176                 /* CHECK_CONDITION */
1177                 if (vstor_packet->vm_srb.srb_status &
1178                         SRB_STATUS_AUTOSENSE_VALID) {
1179                         /* autosense data available */
1180
1181                         storvsc_log(device, STORVSC_LOGGING_WARN,
1182                                 "stor pkt %p autosense data valid - len %d\n",
1183                                 request, vstor_packet->vm_srb.sense_info_length);
1184
1185                         memcpy(request->cmd->sense_buffer,
1186                                vstor_packet->vm_srb.sense_data,
1187                                vstor_packet->vm_srb.sense_info_length);
1188
1189                 }
1190         }
1191
1192         stor_pkt->vm_srb.data_transfer_length =
1193         vstor_packet->vm_srb.data_transfer_length;
1194
1195         storvsc_command_completion(request, stor_device);
1196
1197         if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
1198                 stor_device->drain_notify)
1199                 wake_up(&stor_device->waiting_to_drain);
1200
1201
1202 }
1203
1204 static void storvsc_on_receive(struct storvsc_device *stor_device,
1205                              struct vstor_packet *vstor_packet,
1206                              struct storvsc_cmd_request *request)
1207 {
1208         struct hv_host_device *host_dev;
1209         switch (vstor_packet->operation) {
1210         case VSTOR_OPERATION_COMPLETE_IO:
1211                 storvsc_on_io_completion(stor_device, vstor_packet, request);
1212                 break;
1213
1214         case VSTOR_OPERATION_REMOVE_DEVICE:
1215         case VSTOR_OPERATION_ENUMERATE_BUS:
1216                 host_dev = shost_priv(stor_device->host);
1217                 queue_work(
1218                         host_dev->handle_error_wq, &host_dev->host_scan_work);
1219                 break;
1220
1221         case VSTOR_OPERATION_FCHBA_DATA:
1222                 cache_wwn(stor_device, vstor_packet);
1223 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1224                 fc_host_node_name(stor_device->host) = stor_device->node_name;
1225                 fc_host_port_name(stor_device->host) = stor_device->port_name;
1226 #endif
1227                 break;
1228         default:
1229                 break;
1230         }
1231 }
1232
1233 static void storvsc_on_channel_callback(void *context)
1234 {
1235         struct vmbus_channel *channel = (struct vmbus_channel *)context;
1236         const struct vmpacket_descriptor *desc;
1237         struct hv_device *device;
1238         struct storvsc_device *stor_device;
1239
1240         if (channel->primary_channel != NULL)
1241                 device = channel->primary_channel->device_obj;
1242         else
1243                 device = channel->device_obj;
1244
1245         stor_device = get_in_stor_device(device);
1246         if (!stor_device)
1247                 return;
1248
1249         foreach_vmbus_pkt(desc, channel) {
1250                 void *packet = hv_pkt_data(desc);
1251                 struct storvsc_cmd_request *request;
1252                 u64 cmd_rqst;
1253
1254                 cmd_rqst = vmbus_request_addr(&channel->requestor,
1255                                               desc->trans_id);
1256                 if (cmd_rqst == VMBUS_RQST_ERROR) {
1257                         dev_err(&device->device,
1258                                 "Incorrect transaction id\n");
1259                         continue;
1260                 }
1261
1262                 request = (struct storvsc_cmd_request *)(unsigned long)cmd_rqst;
1263
1264                 if (request == &stor_device->init_request ||
1265                     request == &stor_device->reset_request) {
1266                         memcpy(&request->vstor_packet, packet,
1267                                (sizeof(struct vstor_packet) - vmscsi_size_delta));
1268                         complete(&request->wait_event);
1269                 } else {
1270                         storvsc_on_receive(stor_device, packet, request);
1271                 }
1272         }
1273 }
1274
1275 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size,
1276                                   bool is_fc)
1277 {
1278         struct vmstorage_channel_properties props;
1279         int ret;
1280
1281         memset(&props, 0, sizeof(struct vmstorage_channel_properties));
1282
1283         /*
1284          * The size of vmbus_requestor is an upper bound on the number of requests
1285          * that can be in-progress at any one time across all channels.
1286          */
1287         device->channel->rqstor_size = scsi_driver.can_queue;
1288
1289         ret = vmbus_open(device->channel,
1290                          ring_size,
1291                          ring_size,
1292                          (void *)&props,
1293                          sizeof(struct vmstorage_channel_properties),
1294                          storvsc_on_channel_callback, device->channel);
1295
1296         if (ret != 0)
1297                 return ret;
1298
1299         ret = storvsc_channel_init(device, is_fc);
1300
1301         return ret;
1302 }
1303
1304 static int storvsc_dev_remove(struct hv_device *device)
1305 {
1306         struct storvsc_device *stor_device;
1307
1308         stor_device = hv_get_drvdata(device);
1309
1310         stor_device->destroy = true;
1311
1312         /* Make sure flag is set before waiting */
1313         wmb();
1314
1315         /*
1316          * At this point, all outbound traffic should be disable. We
1317          * only allow inbound traffic (responses) to proceed so that
1318          * outstanding requests can be completed.
1319          */
1320
1321         storvsc_wait_to_drain(stor_device);
1322
1323         /*
1324          * Since we have already drained, we don't need to busy wait
1325          * as was done in final_release_stor_device()
1326          * Note that we cannot set the ext pointer to NULL until
1327          * we have drained - to drain the outgoing packets, we need to
1328          * allow incoming packets.
1329          */
1330         hv_set_drvdata(device, NULL);
1331
1332         /* Close the channel */
1333         vmbus_close(device->channel);
1334
1335         kfree(stor_device->stor_chns);
1336         kfree(stor_device);
1337         return 0;
1338 }
1339
1340 static struct vmbus_channel *get_og_chn(struct storvsc_device *stor_device,
1341                                         u16 q_num)
1342 {
1343         u16 slot = 0;
1344         u16 hash_qnum;
1345         const struct cpumask *node_mask;
1346         int num_channels, tgt_cpu;
1347
1348         if (stor_device->num_sc == 0) {
1349                 stor_device->stor_chns[q_num] = stor_device->device->channel;
1350                 return stor_device->device->channel;
1351         }
1352
1353         /*
1354          * Our channel array is sparsley populated and we
1355          * initiated I/O on a processor/hw-q that does not
1356          * currently have a designated channel. Fix this.
1357          * The strategy is simple:
1358          * I. Ensure NUMA locality
1359          * II. Distribute evenly (best effort)
1360          */
1361
1362         node_mask = cpumask_of_node(cpu_to_node(q_num));
1363
1364         num_channels = 0;
1365         for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1366                 if (cpumask_test_cpu(tgt_cpu, node_mask))
1367                         num_channels++;
1368         }
1369         if (num_channels == 0) {
1370                 stor_device->stor_chns[q_num] = stor_device->device->channel;
1371                 return stor_device->device->channel;
1372         }
1373
1374         hash_qnum = q_num;
1375         while (hash_qnum >= num_channels)
1376                 hash_qnum -= num_channels;
1377
1378         for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1379                 if (!cpumask_test_cpu(tgt_cpu, node_mask))
1380                         continue;
1381                 if (slot == hash_qnum)
1382                         break;
1383                 slot++;
1384         }
1385
1386         stor_device->stor_chns[q_num] = stor_device->stor_chns[tgt_cpu];
1387
1388         return stor_device->stor_chns[q_num];
1389 }
1390
1391
1392 static int storvsc_do_io(struct hv_device *device,
1393                          struct storvsc_cmd_request *request, u16 q_num)
1394 {
1395         struct storvsc_device *stor_device;
1396         struct vstor_packet *vstor_packet;
1397         struct vmbus_channel *outgoing_channel, *channel;
1398         unsigned long flags;
1399         int ret = 0;
1400         const struct cpumask *node_mask;
1401         int tgt_cpu;
1402
1403         vstor_packet = &request->vstor_packet;
1404         stor_device = get_out_stor_device(device);
1405
1406         if (!stor_device)
1407                 return -ENODEV;
1408
1409
1410         request->device  = device;
1411         /*
1412          * Select an appropriate channel to send the request out.
1413          */
1414         /* See storvsc_change_target_cpu(). */
1415         outgoing_channel = READ_ONCE(stor_device->stor_chns[q_num]);
1416         if (outgoing_channel != NULL) {
1417                 if (outgoing_channel->target_cpu == q_num) {
1418                         /*
1419                          * Ideally, we want to pick a different channel if
1420                          * available on the same NUMA node.
1421                          */
1422                         node_mask = cpumask_of_node(cpu_to_node(q_num));
1423                         for_each_cpu_wrap(tgt_cpu,
1424                                  &stor_device->alloced_cpus, q_num + 1) {
1425                                 if (!cpumask_test_cpu(tgt_cpu, node_mask))
1426                                         continue;
1427                                 if (tgt_cpu == q_num)
1428                                         continue;
1429                                 channel = READ_ONCE(
1430                                         stor_device->stor_chns[tgt_cpu]);
1431                                 if (channel == NULL)
1432                                         continue;
1433                                 if (hv_get_avail_to_write_percent(
1434                                                         &channel->outbound)
1435                                                 > ring_avail_percent_lowater) {
1436                                         outgoing_channel = channel;
1437                                         goto found_channel;
1438                                 }
1439                         }
1440
1441                         /*
1442                          * All the other channels on the same NUMA node are
1443                          * busy. Try to use the channel on the current CPU
1444                          */
1445                         if (hv_get_avail_to_write_percent(
1446                                                 &outgoing_channel->outbound)
1447                                         > ring_avail_percent_lowater)
1448                                 goto found_channel;
1449
1450                         /*
1451                          * If we reach here, all the channels on the current
1452                          * NUMA node are busy. Try to find a channel in
1453                          * other NUMA nodes
1454                          */
1455                         for_each_cpu(tgt_cpu, &stor_device->alloced_cpus) {
1456                                 if (cpumask_test_cpu(tgt_cpu, node_mask))
1457                                         continue;
1458                                 channel = READ_ONCE(
1459                                         stor_device->stor_chns[tgt_cpu]);
1460                                 if (channel == NULL)
1461                                         continue;
1462                                 if (hv_get_avail_to_write_percent(
1463                                                         &channel->outbound)
1464                                                 > ring_avail_percent_lowater) {
1465                                         outgoing_channel = channel;
1466                                         goto found_channel;
1467                                 }
1468                         }
1469                 }
1470         } else {
1471                 spin_lock_irqsave(&stor_device->lock, flags);
1472                 outgoing_channel = stor_device->stor_chns[q_num];
1473                 if (outgoing_channel != NULL) {
1474                         spin_unlock_irqrestore(&stor_device->lock, flags);
1475                         goto found_channel;
1476                 }
1477                 outgoing_channel = get_og_chn(stor_device, q_num);
1478                 spin_unlock_irqrestore(&stor_device->lock, flags);
1479         }
1480
1481 found_channel:
1482         vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
1483
1484         vstor_packet->vm_srb.length = (sizeof(struct vmscsi_request) -
1485                                         vmscsi_size_delta);
1486
1487
1488         vstor_packet->vm_srb.sense_info_length = sense_buffer_size;
1489
1490
1491         vstor_packet->vm_srb.data_transfer_length =
1492         request->payload->range.len;
1493
1494         vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
1495
1496         if (request->payload->range.len) {
1497
1498                 ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
1499                                 request->payload, request->payload_sz,
1500                                 vstor_packet,
1501                                 (sizeof(struct vstor_packet) -
1502                                 vmscsi_size_delta),
1503                                 (unsigned long)request);
1504         } else {
1505                 ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
1506                                (sizeof(struct vstor_packet) -
1507                                 vmscsi_size_delta),
1508                                (unsigned long)request,
1509                                VM_PKT_DATA_INBAND,
1510                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1511         }
1512
1513         if (ret != 0)
1514                 return ret;
1515
1516         atomic_inc(&stor_device->num_outstanding_req);
1517
1518         return ret;
1519 }
1520
1521 static int storvsc_device_alloc(struct scsi_device *sdevice)
1522 {
1523         /*
1524          * Set blist flag to permit the reading of the VPD pages even when
1525          * the target may claim SPC-2 compliance. MSFT targets currently
1526          * claim SPC-2 compliance while they implement post SPC-2 features.
1527          * With this flag we can correctly handle WRITE_SAME_16 issues.
1528          *
1529          * Hypervisor reports SCSI_UNKNOWN type for DVD ROM device but
1530          * still supports REPORT LUN.
1531          */
1532         sdevice->sdev_bflags = BLIST_REPORTLUN2 | BLIST_TRY_VPD_PAGES;
1533
1534         return 0;
1535 }
1536
1537 static int storvsc_device_configure(struct scsi_device *sdevice)
1538 {
1539         blk_queue_rq_timeout(sdevice->request_queue, (storvsc_timeout * HZ));
1540
1541         sdevice->no_write_same = 1;
1542
1543         /*
1544          * If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
1545          * if the device is a MSFT virtual device.  If the host is
1546          * WIN10 or newer, allow write_same.
1547          */
1548         if (!strncmp(sdevice->vendor, "Msft", 4)) {
1549                 switch (vmstor_proto_version) {
1550                 case VMSTOR_PROTO_VERSION_WIN8:
1551                 case VMSTOR_PROTO_VERSION_WIN8_1:
1552                         sdevice->scsi_level = SCSI_SPC_3;
1553                         break;
1554                 }
1555
1556                 if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN10)
1557                         sdevice->no_write_same = 0;
1558         }
1559
1560         return 0;
1561 }
1562
1563 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1564                            sector_t capacity, int *info)
1565 {
1566         sector_t nsect = capacity;
1567         sector_t cylinders = nsect;
1568         int heads, sectors_pt;
1569
1570         /*
1571          * We are making up these values; let us keep it simple.
1572          */
1573         heads = 0xff;
1574         sectors_pt = 0x3f;      /* Sectors per track */
1575         sector_div(cylinders, heads * sectors_pt);
1576         if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1577                 cylinders = 0xffff;
1578
1579         info[0] = heads;
1580         info[1] = sectors_pt;
1581         info[2] = (int)cylinders;
1582
1583         return 0;
1584 }
1585
1586 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1587 {
1588         struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1589         struct hv_device *device = host_dev->dev;
1590
1591         struct storvsc_device *stor_device;
1592         struct storvsc_cmd_request *request;
1593         struct vstor_packet *vstor_packet;
1594         int ret, t;
1595
1596         stor_device = get_out_stor_device(device);
1597         if (!stor_device)
1598                 return FAILED;
1599
1600         request = &stor_device->reset_request;
1601         vstor_packet = &request->vstor_packet;
1602         memset(vstor_packet, 0, sizeof(struct vstor_packet));
1603
1604         init_completion(&request->wait_event);
1605
1606         vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1607         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1608         vstor_packet->vm_srb.path_id = stor_device->path_id;
1609
1610         ret = vmbus_sendpacket(device->channel, vstor_packet,
1611                                (sizeof(struct vstor_packet) -
1612                                 vmscsi_size_delta),
1613                                (unsigned long)&stor_device->reset_request,
1614                                VM_PKT_DATA_INBAND,
1615                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1616         if (ret != 0)
1617                 return FAILED;
1618
1619         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1620         if (t == 0)
1621                 return TIMEOUT_ERROR;
1622
1623
1624         /*
1625          * At this point, all outstanding requests in the adapter
1626          * should have been flushed out and return to us
1627          * There is a potential race here where the host may be in
1628          * the process of responding when we return from here.
1629          * Just wait for all in-transit packets to be accounted for
1630          * before we return from here.
1631          */
1632         storvsc_wait_to_drain(stor_device);
1633
1634         return SUCCESS;
1635 }
1636
1637 /*
1638  * The host guarantees to respond to each command, although I/O latencies might
1639  * be unbounded on Azure.  Reset the timer unconditionally to give the host a
1640  * chance to perform EH.
1641  */
1642 static enum blk_eh_timer_return storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
1643 {
1644 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1645         if (scmnd->device->host->transportt == fc_transport_template)
1646                 return fc_eh_timed_out(scmnd);
1647 #endif
1648         return BLK_EH_RESET_TIMER;
1649 }
1650
1651 static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
1652 {
1653         bool allowed = true;
1654         u8 scsi_op = scmnd->cmnd[0];
1655
1656         switch (scsi_op) {
1657         /* the host does not handle WRITE_SAME, log accident usage */
1658         case WRITE_SAME:
1659         /*
1660          * smartd sends this command and the host does not handle
1661          * this. So, don't send it.
1662          */
1663         case SET_WINDOW:
1664                 scmnd->result = ILLEGAL_REQUEST << 16;
1665                 allowed = false;
1666                 break;
1667         default:
1668                 break;
1669         }
1670         return allowed;
1671 }
1672
1673 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1674 {
1675         int ret;
1676         struct hv_host_device *host_dev = shost_priv(host);
1677         struct hv_device *dev = host_dev->dev;
1678         struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
1679         int i;
1680         struct scatterlist *sgl;
1681         unsigned int sg_count = 0;
1682         struct vmscsi_request *vm_srb;
1683         struct scatterlist *cur_sgl;
1684         struct vmbus_packet_mpb_array  *payload;
1685         u32 payload_sz;
1686         u32 length;
1687
1688         if (vmstor_proto_version <= VMSTOR_PROTO_VERSION_WIN8) {
1689                 /*
1690                  * On legacy hosts filter unimplemented commands.
1691                  * Future hosts are expected to correctly handle
1692                  * unsupported commands. Furthermore, it is
1693                  * possible that some of the currently
1694                  * unsupported commands maybe supported in
1695                  * future versions of the host.
1696                  */
1697                 if (!storvsc_scsi_cmd_ok(scmnd)) {
1698                         scmnd->scsi_done(scmnd);
1699                         return 0;
1700                 }
1701         }
1702
1703         /* Setup the cmd request */
1704         cmd_request->cmd = scmnd;
1705
1706         memset(&cmd_request->vstor_packet, 0, sizeof(struct vstor_packet));
1707         vm_srb = &cmd_request->vstor_packet.vm_srb;
1708         vm_srb->win8_extension.time_out_value = 60;
1709
1710         vm_srb->win8_extension.srb_flags |=
1711                 SRB_FLAGS_DISABLE_SYNCH_TRANSFER;
1712
1713         if (scmnd->device->tagged_supported) {
1714                 vm_srb->win8_extension.srb_flags |=
1715                 (SRB_FLAGS_QUEUE_ACTION_ENABLE | SRB_FLAGS_NO_QUEUE_FREEZE);
1716                 vm_srb->win8_extension.queue_tag = SP_UNTAGGED;
1717                 vm_srb->win8_extension.queue_action = SRB_SIMPLE_TAG_REQUEST;
1718         }
1719
1720         /* Build the SRB */
1721         switch (scmnd->sc_data_direction) {
1722         case DMA_TO_DEVICE:
1723                 vm_srb->data_in = WRITE_TYPE;
1724                 vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_OUT;
1725                 break;
1726         case DMA_FROM_DEVICE:
1727                 vm_srb->data_in = READ_TYPE;
1728                 vm_srb->win8_extension.srb_flags |= SRB_FLAGS_DATA_IN;
1729                 break;
1730         case DMA_NONE:
1731                 vm_srb->data_in = UNKNOWN_TYPE;
1732                 vm_srb->win8_extension.srb_flags |= SRB_FLAGS_NO_DATA_TRANSFER;
1733                 break;
1734         default:
1735                 /*
1736                  * This is DMA_BIDIRECTIONAL or something else we are never
1737                  * supposed to see here.
1738                  */
1739                 WARN(1, "Unexpected data direction: %d\n",
1740                      scmnd->sc_data_direction);
1741                 return -EINVAL;
1742         }
1743
1744
1745         vm_srb->port_number = host_dev->port;
1746         vm_srb->path_id = scmnd->device->channel;
1747         vm_srb->target_id = scmnd->device->id;
1748         vm_srb->lun = scmnd->device->lun;
1749
1750         vm_srb->cdb_length = scmnd->cmd_len;
1751
1752         memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1753
1754         sgl = (struct scatterlist *)scsi_sglist(scmnd);
1755         sg_count = scsi_sg_count(scmnd);
1756
1757         length = scsi_bufflen(scmnd);
1758         payload = (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
1759         payload_sz = sizeof(cmd_request->mpb);
1760
1761         if (sg_count) {
1762                 unsigned int hvpgoff = 0;
1763                 unsigned long offset_in_hvpg = sgl->offset & ~HV_HYP_PAGE_MASK;
1764                 unsigned int hvpg_count = HVPFN_UP(offset_in_hvpg + length);
1765                 u64 hvpfn;
1766
1767                 if (hvpg_count > MAX_PAGE_BUFFER_COUNT) {
1768
1769                         payload_sz = (hvpg_count * sizeof(u64) +
1770                                       sizeof(struct vmbus_packet_mpb_array));
1771                         payload = kzalloc(payload_sz, GFP_ATOMIC);
1772                         if (!payload)
1773                                 return SCSI_MLQUEUE_DEVICE_BUSY;
1774                 }
1775
1776                 /*
1777                  * sgl is a list of PAGEs, and payload->range.pfn_array
1778                  * expects the page number in the unit of HV_HYP_PAGE_SIZE (the
1779                  * page size that Hyper-V uses, so here we need to divide PAGEs
1780                  * into HV_HYP_PAGE in case that PAGE_SIZE > HV_HYP_PAGE_SIZE.
1781                  * Besides, payload->range.offset should be the offset in one
1782                  * HV_HYP_PAGE.
1783                  */
1784                 payload->range.len = length;
1785                 payload->range.offset = offset_in_hvpg;
1786                 hvpgoff = sgl->offset >> HV_HYP_PAGE_SHIFT;
1787
1788                 cur_sgl = sgl;
1789                 for (i = 0; i < hvpg_count; i++) {
1790                         /*
1791                          * 'i' is the index of hv pages in the payload and
1792                          * 'hvpgoff' is the offset (in hv pages) of the first
1793                          * hv page in the the first page. The relationship
1794                          * between the sum of 'i' and 'hvpgoff' and the offset
1795                          * (in hv pages) in a payload page ('hvpgoff_in_page')
1796                          * is as follow:
1797                          *
1798                          * |------------------ PAGE -------------------|
1799                          * |   NR_HV_HYP_PAGES_IN_PAGE hvpgs in total  |
1800                          * |hvpg|hvpg| ...              |hvpg|... |hvpg|
1801                          * ^         ^                                 ^                 ^
1802                          * +-hvpgoff-+                                 +-hvpgoff_in_page-+
1803                          *           ^                                                   |
1804                          *           +--------------------- i ---------------------------+
1805                          */
1806                         unsigned int hvpgoff_in_page =
1807                                 (i + hvpgoff) % NR_HV_HYP_PAGES_IN_PAGE;
1808
1809                         /*
1810                          * Two cases that we need to fetch a page:
1811                          * 1) i == 0, the first step or
1812                          * 2) hvpgoff_in_page == 0, when we reach the boundary
1813                          *    of a page.
1814                          */
1815                         if (hvpgoff_in_page == 0 || i == 0) {
1816                                 hvpfn = page_to_hvpfn(sg_page(cur_sgl));
1817                                 cur_sgl = sg_next(cur_sgl);
1818                         }
1819
1820                         payload->range.pfn_array[i] = hvpfn + hvpgoff_in_page;
1821                 }
1822         }
1823
1824         cmd_request->payload = payload;
1825         cmd_request->payload_sz = payload_sz;
1826
1827         /* Invokes the vsc to start an IO */
1828         ret = storvsc_do_io(dev, cmd_request, get_cpu());
1829         put_cpu();
1830
1831         if (ret == -EAGAIN) {
1832                 if (payload_sz > sizeof(cmd_request->mpb))
1833                         kfree(payload);
1834                 /* no more space */
1835                 return SCSI_MLQUEUE_DEVICE_BUSY;
1836         }
1837
1838         return 0;
1839 }
1840
1841 static struct scsi_host_template scsi_driver = {
1842         .module =               THIS_MODULE,
1843         .name =                 "storvsc_host_t",
1844         .cmd_size =             sizeof(struct storvsc_cmd_request),
1845         .bios_param =           storvsc_get_chs,
1846         .queuecommand =         storvsc_queuecommand,
1847         .eh_host_reset_handler =        storvsc_host_reset_handler,
1848         .proc_name =            "storvsc_host",
1849         .eh_timed_out =         storvsc_eh_timed_out,
1850         .slave_alloc =          storvsc_device_alloc,
1851         .slave_configure =      storvsc_device_configure,
1852         .cmd_per_lun =          2048,
1853         .this_id =              -1,
1854         /* Make sure we dont get a sg segment crosses a page boundary */
1855         .dma_boundary =         PAGE_SIZE-1,
1856         /* Ensure there are no gaps in presented sgls */
1857         .virt_boundary_mask =   PAGE_SIZE-1,
1858         .no_write_same =        1,
1859         .track_queue_depth =    1,
1860         .change_queue_depth =   storvsc_change_queue_depth,
1861 };
1862
1863 enum {
1864         SCSI_GUID,
1865         IDE_GUID,
1866         SFC_GUID,
1867 };
1868
1869 static const struct hv_vmbus_device_id id_table[] = {
1870         /* SCSI guid */
1871         { HV_SCSI_GUID,
1872           .driver_data = SCSI_GUID
1873         },
1874         /* IDE guid */
1875         { HV_IDE_GUID,
1876           .driver_data = IDE_GUID
1877         },
1878         /* Fibre Channel GUID */
1879         {
1880           HV_SYNTHFC_GUID,
1881           .driver_data = SFC_GUID
1882         },
1883         { },
1884 };
1885
1886 MODULE_DEVICE_TABLE(vmbus, id_table);
1887
1888 static const struct { guid_t guid; } fc_guid = { HV_SYNTHFC_GUID };
1889
1890 static bool hv_dev_is_fc(struct hv_device *hv_dev)
1891 {
1892         return guid_equal(&fc_guid.guid, &hv_dev->dev_type);
1893 }
1894
1895 static int storvsc_probe(struct hv_device *device,
1896                         const struct hv_vmbus_device_id *dev_id)
1897 {
1898         int ret;
1899         int num_cpus = num_online_cpus();
1900         struct Scsi_Host *host;
1901         struct hv_host_device *host_dev;
1902         bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1903         bool is_fc = ((dev_id->driver_data == SFC_GUID) ? true : false);
1904         int target = 0;
1905         struct storvsc_device *stor_device;
1906         int max_luns_per_target;
1907         int max_targets;
1908         int max_channels;
1909         int max_sub_channels = 0;
1910
1911         /*
1912          * Based on the windows host we are running on,
1913          * set state to properly communicate with the host.
1914          */
1915
1916         if (vmbus_proto_version < VERSION_WIN8) {
1917                 max_luns_per_target = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1918                 max_targets = STORVSC_IDE_MAX_TARGETS;
1919                 max_channels = STORVSC_IDE_MAX_CHANNELS;
1920         } else {
1921                 max_luns_per_target = STORVSC_MAX_LUNS_PER_TARGET;
1922                 max_targets = STORVSC_MAX_TARGETS;
1923                 max_channels = STORVSC_MAX_CHANNELS;
1924                 /*
1925                  * On Windows8 and above, we support sub-channels for storage
1926                  * on SCSI and FC controllers.
1927                  * The number of sub-channels offerred is based on the number of
1928                  * VCPUs in the guest.
1929                  */
1930                 if (!dev_is_ide)
1931                         max_sub_channels =
1932                                 (num_cpus - 1) / storvsc_vcpus_per_sub_channel;
1933         }
1934
1935         scsi_driver.can_queue = max_outstanding_req_per_channel *
1936                                 (max_sub_channels + 1) *
1937                                 (100 - ring_avail_percent_lowater) / 100;
1938
1939         host = scsi_host_alloc(&scsi_driver,
1940                                sizeof(struct hv_host_device));
1941         if (!host)
1942                 return -ENOMEM;
1943
1944         host_dev = shost_priv(host);
1945         memset(host_dev, 0, sizeof(struct hv_host_device));
1946
1947         host_dev->port = host->host_no;
1948         host_dev->dev = device;
1949         host_dev->host = host;
1950
1951
1952         stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1953         if (!stor_device) {
1954                 ret = -ENOMEM;
1955                 goto err_out0;
1956         }
1957
1958         stor_device->destroy = false;
1959         init_waitqueue_head(&stor_device->waiting_to_drain);
1960         stor_device->device = device;
1961         stor_device->host = host;
1962         spin_lock_init(&stor_device->lock);
1963         hv_set_drvdata(device, stor_device);
1964
1965         stor_device->port_number = host->host_no;
1966         ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size, is_fc);
1967         if (ret)
1968                 goto err_out1;
1969
1970         host_dev->path = stor_device->path_id;
1971         host_dev->target = stor_device->target_id;
1972
1973         switch (dev_id->driver_data) {
1974         case SFC_GUID:
1975                 host->max_lun = STORVSC_FC_MAX_LUNS_PER_TARGET;
1976                 host->max_id = STORVSC_FC_MAX_TARGETS;
1977                 host->max_channel = STORVSC_FC_MAX_CHANNELS - 1;
1978 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
1979                 host->transportt = fc_transport_template;
1980 #endif
1981                 break;
1982
1983         case SCSI_GUID:
1984                 host->max_lun = max_luns_per_target;
1985                 host->max_id = max_targets;
1986                 host->max_channel = max_channels - 1;
1987                 break;
1988
1989         default:
1990                 host->max_lun = STORVSC_IDE_MAX_LUNS_PER_TARGET;
1991                 host->max_id = STORVSC_IDE_MAX_TARGETS;
1992                 host->max_channel = STORVSC_IDE_MAX_CHANNELS - 1;
1993                 break;
1994         }
1995         /* max cmd length */
1996         host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1997
1998         /*
1999          * set the table size based on the info we got
2000          * from the host.
2001          */
2002         host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT);
2003         /*
2004          * For non-IDE disks, the host supports multiple channels.
2005          * Set the number of HW queues we are supporting.
2006          */
2007         if (!dev_is_ide)
2008                 host->nr_hw_queues = num_present_cpus();
2009
2010         /*
2011          * Set the error handler work queue.
2012          */
2013         host_dev->handle_error_wq =
2014                         alloc_ordered_workqueue("storvsc_error_wq_%d",
2015                                                 WQ_MEM_RECLAIM,
2016                                                 host->host_no);
2017         if (!host_dev->handle_error_wq) {
2018                 ret = -ENOMEM;
2019                 goto err_out2;
2020         }
2021         INIT_WORK(&host_dev->host_scan_work, storvsc_host_scan);
2022         /* Register the HBA and start the scsi bus scan */
2023         ret = scsi_add_host(host, &device->device);
2024         if (ret != 0)
2025                 goto err_out3;
2026
2027         if (!dev_is_ide) {
2028                 scsi_scan_host(host);
2029         } else {
2030                 target = (device->dev_instance.b[5] << 8 |
2031                          device->dev_instance.b[4]);
2032                 ret = scsi_add_device(host, 0, target, 0);
2033                 if (ret)
2034                         goto err_out4;
2035         }
2036 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2037         if (host->transportt == fc_transport_template) {
2038                 struct fc_rport_identifiers ids = {
2039                         .roles = FC_PORT_ROLE_FCP_DUMMY_INITIATOR,
2040                 };
2041
2042                 fc_host_node_name(host) = stor_device->node_name;
2043                 fc_host_port_name(host) = stor_device->port_name;
2044                 stor_device->rport = fc_remote_port_add(host, 0, &ids);
2045                 if (!stor_device->rport) {
2046                         ret = -ENOMEM;
2047                         goto err_out4;
2048                 }
2049         }
2050 #endif
2051         return 0;
2052
2053 err_out4:
2054         scsi_remove_host(host);
2055
2056 err_out3:
2057         destroy_workqueue(host_dev->handle_error_wq);
2058
2059 err_out2:
2060         /*
2061          * Once we have connected with the host, we would need to
2062          * to invoke storvsc_dev_remove() to rollback this state and
2063          * this call also frees up the stor_device; hence the jump around
2064          * err_out1 label.
2065          */
2066         storvsc_dev_remove(device);
2067         goto err_out0;
2068
2069 err_out1:
2070         kfree(stor_device->stor_chns);
2071         kfree(stor_device);
2072
2073 err_out0:
2074         scsi_host_put(host);
2075         return ret;
2076 }
2077
2078 /* Change a scsi target's queue depth */
2079 static int storvsc_change_queue_depth(struct scsi_device *sdev, int queue_depth)
2080 {
2081         if (queue_depth > scsi_driver.can_queue)
2082                 queue_depth = scsi_driver.can_queue;
2083
2084         return scsi_change_queue_depth(sdev, queue_depth);
2085 }
2086
2087 static int storvsc_remove(struct hv_device *dev)
2088 {
2089         struct storvsc_device *stor_device = hv_get_drvdata(dev);
2090         struct Scsi_Host *host = stor_device->host;
2091         struct hv_host_device *host_dev = shost_priv(host);
2092
2093 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2094         if (host->transportt == fc_transport_template) {
2095                 fc_remote_port_delete(stor_device->rport);
2096                 fc_remove_host(host);
2097         }
2098 #endif
2099         destroy_workqueue(host_dev->handle_error_wq);
2100         scsi_remove_host(host);
2101         storvsc_dev_remove(dev);
2102         scsi_host_put(host);
2103
2104         return 0;
2105 }
2106
2107 static int storvsc_suspend(struct hv_device *hv_dev)
2108 {
2109         struct storvsc_device *stor_device = hv_get_drvdata(hv_dev);
2110         struct Scsi_Host *host = stor_device->host;
2111         struct hv_host_device *host_dev = shost_priv(host);
2112
2113         storvsc_wait_to_drain(stor_device);
2114
2115         drain_workqueue(host_dev->handle_error_wq);
2116
2117         vmbus_close(hv_dev->channel);
2118
2119         kfree(stor_device->stor_chns);
2120         stor_device->stor_chns = NULL;
2121
2122         cpumask_clear(&stor_device->alloced_cpus);
2123
2124         return 0;
2125 }
2126
2127 static int storvsc_resume(struct hv_device *hv_dev)
2128 {
2129         int ret;
2130
2131         ret = storvsc_connect_to_vsp(hv_dev, storvsc_ringbuffer_size,
2132                                      hv_dev_is_fc(hv_dev));
2133         return ret;
2134 }
2135
2136 static struct hv_driver storvsc_drv = {
2137         .name = KBUILD_MODNAME,
2138         .id_table = id_table,
2139         .probe = storvsc_probe,
2140         .remove = storvsc_remove,
2141         .suspend = storvsc_suspend,
2142         .resume = storvsc_resume,
2143         .driver = {
2144                 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
2145         },
2146 };
2147
2148 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2149 static struct fc_function_template fc_transport_functions = {
2150         .show_host_node_name = 1,
2151         .show_host_port_name = 1,
2152 };
2153 #endif
2154
2155 static int __init storvsc_drv_init(void)
2156 {
2157         int ret;
2158
2159         /*
2160          * Divide the ring buffer data size (which is 1 page less
2161          * than the ring buffer size since that page is reserved for
2162          * the ring buffer indices) by the max request size (which is
2163          * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
2164          */
2165         max_outstanding_req_per_channel =
2166                 ((storvsc_ringbuffer_size - PAGE_SIZE) /
2167                 ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
2168                 sizeof(struct vstor_packet) + sizeof(u64) -
2169                 vmscsi_size_delta,
2170                 sizeof(u64)));
2171
2172 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2173         fc_transport_template = fc_attach_transport(&fc_transport_functions);
2174         if (!fc_transport_template)
2175                 return -ENODEV;
2176 #endif
2177
2178         ret = vmbus_driver_register(&storvsc_drv);
2179
2180 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2181         if (ret)
2182                 fc_release_transport(fc_transport_template);
2183 #endif
2184
2185         return ret;
2186 }
2187
2188 static void __exit storvsc_drv_exit(void)
2189 {
2190         vmbus_driver_unregister(&storvsc_drv);
2191 #if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
2192         fc_release_transport(fc_transport_template);
2193 #endif
2194 }
2195
2196 MODULE_LICENSE("GPL");
2197 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
2198 module_init(storvsc_drv_init);
2199 module_exit(storvsc_drv_exit);