drivers/staging/hv/storvsc_drv.c

   1 /*
   2  * Copyright (c) 2009, Microsoft Corporation.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms and conditions of the GNU General Public License,
   6  * version 2, as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  15  * Place - Suite 330, Boston, MA 02111-1307 USA.
  16  *
  17  * Authors:
  18  *   Haiyang Zhang <haiyangz@microsoft.com>
  19  *   Hank Janssen  <hjanssen@microsoft.com>
  20  *   K. Y. Srinivasan <kys@microsoft.com>
  21  */
  22
  23 #include <linux/kernel.h>
  24 #include <linux/wait.h>
  25 #include <linux/sched.h>
  26 #include <linux/completion.h>
  27 #include <linux/string.h>
  28 #include <linux/mm.h>
  29 #include <linux/delay.h>
  30 #include <linux/init.h>
  31 #include <linux/slab.h>
  32 #include <linux/module.h>
  33 #include <linux/device.h>
  34 #include <linux/hyperv.h>
  35 #include <linux/mempool.h>
  36 #include <scsi/scsi.h>
  37 #include <scsi/scsi_cmnd.h>
  38 #include <scsi/scsi_host.h>
  39 #include <scsi/scsi_device.h>
  40 #include <scsi/scsi_tcq.h>
  41 #include <scsi/scsi_eh.h>
  42 #include <scsi/scsi_devinfo.h>
  43 #include <scsi/scsi_dbg.h>
  44
  45
  46 #define STORVSC_MIN_BUF_NR                              64
  47 #define STORVSC_RING_BUFFER_SIZE                        (20*PAGE_SIZE)
  48 static int storvsc_ringbuffer_size = STORVSC_RING_BUFFER_SIZE;
  49
  50 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
  51 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
  52
  53 /* to alert the user that structure sizes may be mismatched even though the */
  54 /* protocol versions match. */
  55
  56
  57 #define REVISION_STRING(REVISION_) #REVISION_
  58 #define FILL_VMSTOR_REVISION(RESULT_LVALUE_)                            \
  59         do {                                                            \
  60                 char *revision_string                                   \
  61                         = REVISION_STRING($Rev : 6 $) + 6;              \
  62                 RESULT_LVALUE_ = 0;                                     \
  63                 while (*revision_string >= '0'                          \
  64                         && *revision_string <= '9') {                   \
  65                         RESULT_LVALUE_ *= 10;                           \
  66                         RESULT_LVALUE_ += *revision_string - '0';       \
  67                         revision_string++;                              \
  68                 }                                                       \
  69         } while (0)
  70
  71 /* Major/minor macros.  Minor version is in LSB, meaning that earlier flat */
  72 /* version numbers will be interpreted as "0.x" (i.e., 1 becomes 0.1). */
  73 #define VMSTOR_PROTOCOL_MAJOR(VERSION_)         (((VERSION_) >> 8) & 0xff)
  74 #define VMSTOR_PROTOCOL_MINOR(VERSION_)         (((VERSION_))      & 0xff)
  75 #define VMSTOR_PROTOCOL_VERSION(MAJOR_, MINOR_) ((((MAJOR_) & 0xff) << 8) | \
  76                                                  (((MINOR_) & 0xff)))
  77 #define VMSTOR_INVALID_PROTOCOL_VERSION         (-1)
  78
  79 /* Version history: */
  80 /* V1 Beta                    0.1 */
  81 /* V1 RC < 2008/1/31          1.0 */
  82 /* V1 RC > 2008/1/31          2.0 */
  83 #define VMSTOR_PROTOCOL_VERSION_CURRENT VMSTOR_PROTOCOL_VERSION(4, 2)
  84
  85
  86
  87
  88 /*  This will get replaced with the max transfer length that is possible on */
  89 /*  the host adapter. */
  90 /*  The max transfer length will be published when we offer a vmbus channel. */
  91 #define MAX_TRANSFER_LENGTH     0x40000
  92 #define DEFAULT_PACKET_SIZE (sizeof(struct vmdata_gpa_direct) + \
  93                         sizeof(struct vstor_packet) +           \
  94                         sizesizeof(u64) * (MAX_TRANSFER_LENGTH / PAGE_SIZE)))
  95
  96
  97 /*  Packet structure describing virtual storage requests. */
  98 enum vstor_packet_operation {
  99         VSTOR_OPERATION_COMPLETE_IO             = 1,
 100         VSTOR_OPERATION_REMOVE_DEVICE           = 2,
 101         VSTOR_OPERATION_EXECUTE_SRB             = 3,
 102         VSTOR_OPERATION_RESET_LUN               = 4,
 103         VSTOR_OPERATION_RESET_ADAPTER           = 5,
 104         VSTOR_OPERATION_RESET_BUS               = 6,
 105         VSTOR_OPERATION_BEGIN_INITIALIZATION    = 7,
 106         VSTOR_OPERATION_END_INITIALIZATION      = 8,
 107         VSTOR_OPERATION_QUERY_PROTOCOL_VERSION  = 9,
 108         VSTOR_OPERATION_QUERY_PROPERTIES        = 10,
 109         VSTOR_OPERATION_ENUMERATE_BUS           = 11,
 110         VSTOR_OPERATION_MAXIMUM                 = 11
 111 };
 112
 113 /*
 114  * Platform neutral description of a scsi request -
 115  * this remains the same across the write regardless of 32/64 bit
 116  * note: it's patterned off the SCSI_PASS_THROUGH structure
 117  */
 118 #define CDB16GENERIC_LENGTH                     0x10
 119
 120 #ifndef SENSE_BUFFER_SIZE
 121 #define SENSE_BUFFER_SIZE                       0x12
 122 #endif
 123
 124 #define MAX_DATA_BUF_LEN_WITH_PADDING           0x14
 125
 126 struct vmscsi_request {
 127         unsigned short length;
 128         unsigned char srb_status;
 129         unsigned char scsi_status;
 130
 131         unsigned char port_number;
 132         unsigned char path_id;
 133         unsigned char target_id;
 134         unsigned char lun;
 135
 136         unsigned char cdb_length;
 137         unsigned char sense_info_length;
 138         unsigned char data_in;
 139         unsigned char reserved;
 140
 141         unsigned int data_transfer_length;
 142
 143         union {
 144                 unsigned char cdb[CDB16GENERIC_LENGTH];
 145                 unsigned char sense_data[SENSE_BUFFER_SIZE];
 146                 unsigned char reserved_array[MAX_DATA_BUF_LEN_WITH_PADDING];
 147         };
 148 } __attribute((packed));
 149
 150
 151 /*
 152  * This structure is sent during the intialization phase to get the different
 153  * properties of the channel.
 154  */
 155 struct vmstorage_channel_properties {
 156         unsigned short protocol_version;
 157         unsigned char path_id;
 158         unsigned char target_id;
 159
 160         /* Note: port number is only really known on the client side */
 161         unsigned int port_number;
 162         unsigned int flags;
 163         unsigned int max_transfer_bytes;
 164
 165         /*  This id is unique for each channel and will correspond with */
 166         /*  vendor specific data in the inquirydata */
 167         unsigned long long unique_id;
 168 } __packed;
 169
 170 /*  This structure is sent during the storage protocol negotiations. */
 171 struct vmstorage_protocol_version {
 172         /* Major (MSW) and minor (LSW) version numbers. */
 173         unsigned short major_minor;
 174
 175         /*
 176          * Revision number is auto-incremented whenever this file is changed
 177          * (See FILL_VMSTOR_REVISION macro above).  Mismatch does not
 178          * definitely indicate incompatibility--but it does indicate mismatched
 179          * builds.
 180          */
 181         unsigned short revision;
 182 } __packed;
 183
 184 /* Channel Property Flags */
 185 #define STORAGE_CHANNEL_REMOVABLE_FLAG          0x1
 186 #define STORAGE_CHANNEL_EMULATED_IDE_FLAG       0x2
 187
 188 struct vstor_packet {
 189         /* Requested operation type */
 190         enum vstor_packet_operation operation;
 191
 192         /*  Flags - see below for values */
 193         unsigned int flags;
 194
 195         /* Status of the request returned from the server side. */
 196         unsigned int status;
 197
 198         /* Data payload area */
 199         union {
 200                 /*
 201                  * Structure used to forward SCSI commands from the
 202                  * client to the server.
 203                  */
 204                 struct vmscsi_request vm_srb;
 205
 206                 /* Structure used to query channel properties. */
 207                 struct vmstorage_channel_properties storage_channel_properties;
 208
 209                 /* Used during version negotiations. */
 210                 struct vmstorage_protocol_version version;
 211         };
 212 } __packed;
 213
 214 /* Packet flags */
 215 /*
 216  * This flag indicates that the server should send back a completion for this
 217  * packet.
 218  */
 219 #define REQUEST_COMPLETION_FLAG 0x1
 220
 221 /*  This is the set of flags that the vsc can set in any packets it sends */
 222 #define VSC_LEGAL_FLAGS         (REQUEST_COMPLETION_FLAG)
 223
 224
 225 /* Defines */
 226
 227 #define STORVSC_MAX_IO_REQUESTS                         128
 228
 229 /*
 230  * In Hyper-V, each port/path/target maps to 1 scsi host adapter.  In
 231  * reality, the path/target is not used (ie always set to 0) so our
 232  * scsi host adapter essentially has 1 bus with 1 target that contains
 233  * up to 256 luns.
 234  */
 235 #define STORVSC_MAX_LUNS_PER_TARGET                     64
 236 #define STORVSC_MAX_TARGETS                             1
 237 #define STORVSC_MAX_CHANNELS                            1
 238 #define STORVSC_MAX_CMD_LEN                             16
 239
 240 /* Matches Windows-end */
 241 enum storvsc_request_type {
 242         WRITE_TYPE,
 243         READ_TYPE,
 244         UNKNOWN_TYPE,
 245 };
 246
 247
 248 struct hv_storvsc_request {
 249         struct hv_device *device;
 250
 251         /* Synchronize the request/response if needed */
 252         struct completion wait_event;
 253
 254         unsigned char *sense_buffer;
 255         void *context;
 256         void (*on_io_completion)(struct hv_storvsc_request *request);
 257         struct hv_multipage_buffer data_buffer;
 258
 259         struct vstor_packet vstor_packet;
 260 };
 261
 262
 263 /* A storvsc device is a device object that contains a vmbus channel */
 264 struct storvsc_device {
 265         struct hv_device *device;
 266
 267         bool     destroy;
 268         bool     drain_notify;
 269         atomic_t num_outstanding_req;
 270         struct Scsi_Host *host;
 271
 272         wait_queue_head_t waiting_to_drain;
 273
 274         /*
 275          * Each unique Port/Path/Target represents 1 channel ie scsi
 276          * controller. In reality, the pathid, targetid is always 0
 277          * and the port is set by us
 278          */
 279         unsigned int port_number;
 280         unsigned char path_id;
 281         unsigned char target_id;
 282
 283         /* Used for vsc/vsp channel reset process */
 284         struct hv_storvsc_request init_request;
 285         struct hv_storvsc_request reset_request;
 286 };
 287
 288 struct hv_host_device {
 289         struct hv_device *dev;
 290         struct kmem_cache *request_pool;
 291         mempool_t *request_mempool;
 292         unsigned int port;
 293         unsigned char path;
 294         unsigned char target;
 295 };
 296
 297 struct storvsc_cmd_request {
 298         struct list_head entry;
 299         struct scsi_cmnd *cmd;
 300
 301         unsigned int bounce_sgl_count;
 302         struct scatterlist *bounce_sgl;
 303
 304         struct hv_storvsc_request request;
 305 };
 306
 307 struct storvsc_scan_work {
 308         struct work_struct work;
 309         struct Scsi_Host *host;
 310         uint lun;
 311 };
 312
 313 static void storvsc_bus_scan(struct work_struct *work)
 314 {
 315         struct storvsc_scan_work *wrk;
 316         int id, order_id;
 317
 318         wrk = container_of(work, struct storvsc_scan_work, work);
 319         for (id = 0; id < wrk->host->max_id; ++id) {
 320                 if (wrk->host->reverse_ordering)
 321                         order_id = wrk->host->max_id - id - 1;
 322                 else
 323                         order_id = id;
 324
 325                 scsi_scan_target(&wrk->host->shost_gendev, 0,
 326                                 order_id, SCAN_WILD_CARD, 1);
 327         }
 328         kfree(wrk);
 329 }
 330
 331 static void storvsc_remove_lun(struct work_struct *work)
 332 {
 333         struct storvsc_scan_work *wrk;
 334         struct scsi_device *sdev;
 335
 336         wrk = container_of(work, struct storvsc_scan_work, work);
 337         if (!scsi_host_get(wrk->host))
 338                 goto done;
 339
 340         sdev = scsi_device_lookup(wrk->host, 0, 0, wrk->lun);
 341
 342         if (sdev) {
 343                 scsi_remove_device(sdev);
 344                 scsi_device_put(sdev);
 345         }
 346         scsi_host_put(wrk->host);
 347
 348 done:
 349         kfree(wrk);
 350 }
 351
 352 static inline struct storvsc_device *get_out_stor_device(
 353                                         struct hv_device *device)
 354 {
 355         struct storvsc_device *stor_device;
 356
 357         stor_device = hv_get_drvdata(device);
 358
 359         if (stor_device && stor_device->destroy)
 360                 stor_device = NULL;
 361
 362         return stor_device;
 363 }
 364
 365
 366 static inline void storvsc_wait_to_drain(struct storvsc_device *dev)
 367 {
 368         dev->drain_notify = true;
 369         wait_event(dev->waiting_to_drain,
 370                    atomic_read(&dev->num_outstanding_req) == 0);
 371         dev->drain_notify = false;
 372 }
 373
 374 static inline struct storvsc_device *get_in_stor_device(
 375                                         struct hv_device *device)
 376 {
 377         struct storvsc_device *stor_device;
 378
 379         stor_device = hv_get_drvdata(device);
 380
 381         if (!stor_device)
 382                 goto get_in_err;
 383
 384         /*
 385          * If the device is being destroyed; allow incoming
 386          * traffic only to cleanup outstanding requests.
 387          */
 388
 389         if (stor_device->destroy  &&
 390                 (atomic_read(&stor_device->num_outstanding_req) == 0))
 391                 stor_device = NULL;
 392
 393 get_in_err:
 394         return stor_device;
 395
 396 }
 397
 398 static int storvsc_channel_init(struct hv_device *device)
 399 {
 400         struct storvsc_device *stor_device;
 401         struct hv_storvsc_request *request;
 402         struct vstor_packet *vstor_packet;
 403         int ret, t;
 404
 405         stor_device = get_out_stor_device(device);
 406         if (!stor_device)
 407                 return -ENODEV;
 408
 409         request = &stor_device->init_request;
 410         vstor_packet = &request->vstor_packet;
 411
 412         /*
 413          * Now, initiate the vsc/vsp initialization protocol on the open
 414          * channel
 415          */
 416         memset(request, 0, sizeof(struct hv_storvsc_request));
 417         init_completion(&request->wait_event);
 418         vstor_packet->operation = VSTOR_OPERATION_BEGIN_INITIALIZATION;
 419         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 420
 421         ret = vmbus_sendpacket(device->channel, vstor_packet,
 422                                sizeof(struct vstor_packet),
 423                                (unsigned long)request,
 424                                VM_PKT_DATA_INBAND,
 425                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 426         if (ret != 0)
 427                 goto cleanup;
 428
 429         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
 430         if (t == 0) {
 431                 ret = -ETIMEDOUT;
 432                 goto cleanup;
 433         }
 434
 435         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
 436             vstor_packet->status != 0)
 437                 goto cleanup;
 438
 439
 440         /* reuse the packet for version range supported */
 441         memset(vstor_packet, 0, sizeof(struct vstor_packet));
 442         vstor_packet->operation = VSTOR_OPERATION_QUERY_PROTOCOL_VERSION;
 443         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 444
 445         vstor_packet->version.major_minor = VMSTOR_PROTOCOL_VERSION_CURRENT;
 446         FILL_VMSTOR_REVISION(vstor_packet->version.revision);
 447
 448         ret = vmbus_sendpacket(device->channel, vstor_packet,
 449                                sizeof(struct vstor_packet),
 450                                (unsigned long)request,
 451                                VM_PKT_DATA_INBAND,
 452                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 453         if (ret != 0)
 454                 goto cleanup;
 455
 456         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
 457         if (t == 0) {
 458                 ret = -ETIMEDOUT;
 459                 goto cleanup;
 460         }
 461
 462         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
 463             vstor_packet->status != 0)
 464                 goto cleanup;
 465
 466
 467         memset(vstor_packet, 0, sizeof(struct vstor_packet));
 468         vstor_packet->operation = VSTOR_OPERATION_QUERY_PROPERTIES;
 469         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 470         vstor_packet->storage_channel_properties.port_number =
 471                                         stor_device->port_number;
 472
 473         ret = vmbus_sendpacket(device->channel, vstor_packet,
 474                                sizeof(struct vstor_packet),
 475                                (unsigned long)request,
 476                                VM_PKT_DATA_INBAND,
 477                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 478
 479         if (ret != 0)
 480                 goto cleanup;
 481
 482         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
 483         if (t == 0) {
 484                 ret = -ETIMEDOUT;
 485                 goto cleanup;
 486         }
 487
 488         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
 489             vstor_packet->status != 0)
 490                 goto cleanup;
 491
 492         stor_device->path_id = vstor_packet->storage_channel_properties.path_id;
 493         stor_device->target_id
 494                 = vstor_packet->storage_channel_properties.target_id;
 495
 496         memset(vstor_packet, 0, sizeof(struct vstor_packet));
 497         vstor_packet->operation = VSTOR_OPERATION_END_INITIALIZATION;
 498         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 499
 500         ret = vmbus_sendpacket(device->channel, vstor_packet,
 501                                sizeof(struct vstor_packet),
 502                                (unsigned long)request,
 503                                VM_PKT_DATA_INBAND,
 504                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 505
 506         if (ret != 0)
 507                 goto cleanup;
 508
 509         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
 510         if (t == 0) {
 511                 ret = -ETIMEDOUT;
 512                 goto cleanup;
 513         }
 514
 515         if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO ||
 516             vstor_packet->status != 0)
 517                 goto cleanup;
 518
 519
 520 cleanup:
 521         return ret;
 522 }
 523
 524 static void storvsc_on_io_completion(struct hv_device *device,
 525                                   struct vstor_packet *vstor_packet,
 526                                   struct hv_storvsc_request *request)
 527 {
 528         struct storvsc_device *stor_device;
 529         struct vstor_packet *stor_pkt;
 530
 531         stor_device = hv_get_drvdata(device);
 532         stor_pkt = &request->vstor_packet;
 533
 534         /*
 535          * The current SCSI handling on the host side does
 536          * not correctly handle:
 537          * INQUIRY command with page code parameter set to 0x80
 538          * MODE_SENSE command with cmd[2] == 0x1c
 539          *
 540          * Setup srb and scsi status so this won't be fatal.
 541          * We do this so we can distinguish truly fatal failues
 542          * (srb status == 0x4) and off-line the device in that case.
 543          */
 544
 545         if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
 546                 (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
 547                 vstor_packet->vm_srb.scsi_status = 0;
 548                 vstor_packet->vm_srb.srb_status = 0x1;
 549         }
 550
 551
 552         /* Copy over the status...etc */
 553         stor_pkt->vm_srb.scsi_status = vstor_packet->vm_srb.scsi_status;
 554         stor_pkt->vm_srb.srb_status = vstor_packet->vm_srb.srb_status;
 555         stor_pkt->vm_srb.sense_info_length =
 556         vstor_packet->vm_srb.sense_info_length;
 557
 558         if (vstor_packet->vm_srb.scsi_status != 0 ||
 559                 vstor_packet->vm_srb.srb_status != 1){
 560                 dev_warn(&device->device,
 561                          "cmd 0x%x scsi status 0x%x srb status 0x%x\n",
 562                          stor_pkt->vm_srb.cdb[0],
 563                          vstor_packet->vm_srb.scsi_status,
 564                          vstor_packet->vm_srb.srb_status);
 565         }
 566
 567         if ((vstor_packet->vm_srb.scsi_status & 0xFF) == 0x02) {
 568                 /* CHECK_CONDITION */
 569                 if (vstor_packet->vm_srb.srb_status & 0x80) {
 570                         /* autosense data available */
 571                         dev_warn(&device->device,
 572                                  "stor pkt %p autosense data valid - len %d\n",
 573                                  request,
 574                                  vstor_packet->vm_srb.sense_info_length);
 575
 576                         memcpy(request->sense_buffer,
 577                                vstor_packet->vm_srb.sense_data,
 578                                vstor_packet->vm_srb.sense_info_length);
 579
 580                 }
 581         }
 582
 583         stor_pkt->vm_srb.data_transfer_length =
 584         vstor_packet->vm_srb.data_transfer_length;
 585
 586         request->on_io_completion(request);
 587
 588         if (atomic_dec_and_test(&stor_device->num_outstanding_req) &&
 589                 stor_device->drain_notify)
 590                 wake_up(&stor_device->waiting_to_drain);
 591
 592
 593 }
 594
 595 static void storvsc_on_receive(struct hv_device *device,
 596                              struct vstor_packet *vstor_packet,
 597                              struct hv_storvsc_request *request)
 598 {
 599         struct storvsc_scan_work *work;
 600         struct storvsc_device *stor_device;
 601
 602         switch (vstor_packet->operation) {
 603         case VSTOR_OPERATION_COMPLETE_IO:
 604                 storvsc_on_io_completion(device, vstor_packet, request);
 605                 break;
 606
 607         case VSTOR_OPERATION_REMOVE_DEVICE:
 608         case VSTOR_OPERATION_ENUMERATE_BUS:
 609                 stor_device = get_in_stor_device(device);
 610                 work = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
 611                 if (!work)
 612                         return;
 613
 614                 INIT_WORK(&work->work, storvsc_bus_scan);
 615                 work->host = stor_device->host;
 616                 schedule_work(&work->work);
 617                 break;
 618
 619         default:
 620                 break;
 621         }
 622 }
 623
 624 static void storvsc_on_channel_callback(void *context)
 625 {
 626         struct hv_device *device = (struct hv_device *)context;
 627         struct storvsc_device *stor_device;
 628         u32 bytes_recvd;
 629         u64 request_id;
 630         unsigned char packet[ALIGN(sizeof(struct vstor_packet), 8)];
 631         struct hv_storvsc_request *request;
 632         int ret;
 633
 634
 635         stor_device = get_in_stor_device(device);
 636         if (!stor_device)
 637                 return;
 638
 639         do {
 640                 ret = vmbus_recvpacket(device->channel, packet,
 641                                        ALIGN(sizeof(struct vstor_packet), 8),
 642                                        &bytes_recvd, &request_id);
 643                 if (ret == 0 && bytes_recvd > 0) {
 644
 645                         request = (struct hv_storvsc_request *)
 646                                         (unsigned long)request_id;
 647
 648                         if ((request == &stor_device->init_request) ||
 649                             (request == &stor_device->reset_request)) {
 650
 651                                 memcpy(&request->vstor_packet, packet,
 652                                        sizeof(struct vstor_packet));
 653                                 complete(&request->wait_event);
 654                         } else {
 655                                 storvsc_on_receive(device,
 656                                                 (struct vstor_packet *)packet,
 657                                                 request);
 658                         }
 659                 } else {
 660                         break;
 661                 }
 662         } while (1);
 663
 664         return;
 665 }
 666
 667 static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size)
 668 {
 669         struct vmstorage_channel_properties props;
 670         int ret;
 671
 672         memset(&props, 0, sizeof(struct vmstorage_channel_properties));
 673
 674         /* Open the channel */
 675         ret = vmbus_open(device->channel,
 676                          ring_size,
 677                          ring_size,
 678                          (void *)&props,
 679                          sizeof(struct vmstorage_channel_properties),
 680                          storvsc_on_channel_callback, device);
 681
 682         if (ret != 0)
 683                 return ret;
 684
 685         ret = storvsc_channel_init(device);
 686
 687         return ret;
 688 }
 689
 690 static int storvsc_dev_remove(struct hv_device *device)
 691 {
 692         struct storvsc_device *stor_device;
 693         unsigned long flags;
 694
 695         stor_device = hv_get_drvdata(device);
 696
 697         spin_lock_irqsave(&device->channel->inbound_lock, flags);
 698         stor_device->destroy = true;
 699         spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
 700
 701         /*
 702          * At this point, all outbound traffic should be disable. We
 703          * only allow inbound traffic (responses) to proceed so that
 704          * outstanding requests can be completed.
 705          */
 706
 707         storvsc_wait_to_drain(stor_device);
 708
 709         /*
 710          * Since we have already drained, we don't need to busy wait
 711          * as was done in final_release_stor_device()
 712          * Note that we cannot set the ext pointer to NULL until
 713          * we have drained - to drain the outgoing packets, we need to
 714          * allow incoming packets.
 715          */
 716         spin_lock_irqsave(&device->channel->inbound_lock, flags);
 717         hv_set_drvdata(device, NULL);
 718         spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
 719
 720         /* Close the channel */
 721         vmbus_close(device->channel);
 722
 723         kfree(stor_device);
 724         return 0;
 725 }
 726
 727 static int storvsc_do_io(struct hv_device *device,
 728                               struct hv_storvsc_request *request)
 729 {
 730         struct storvsc_device *stor_device;
 731         struct vstor_packet *vstor_packet;
 732         int ret = 0;
 733
 734         vstor_packet = &request->vstor_packet;
 735         stor_device = get_out_stor_device(device);
 736
 737         if (!stor_device)
 738                 return -ENODEV;
 739
 740
 741         request->device  = device;
 742
 743
 744         vstor_packet->flags |= REQUEST_COMPLETION_FLAG;
 745
 746         vstor_packet->vm_srb.length = sizeof(struct vmscsi_request);
 747
 748
 749         vstor_packet->vm_srb.sense_info_length = SENSE_BUFFER_SIZE;
 750
 751
 752         vstor_packet->vm_srb.data_transfer_length =
 753         request->data_buffer.len;
 754
 755         vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
 756
 757         if (request->data_buffer.len) {
 758                 ret = vmbus_sendpacket_multipagebuffer(device->channel,
 759                                 &request->data_buffer,
 760                                 vstor_packet,
 761                                 sizeof(struct vstor_packet),
 762                                 (unsigned long)request);
 763         } else {
 764                 ret = vmbus_sendpacket(device->channel, vstor_packet,
 765                                sizeof(struct vstor_packet),
 766                                (unsigned long)request,
 767                                VM_PKT_DATA_INBAND,
 768                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 769         }
 770
 771         if (ret != 0)
 772                 return ret;
 773
 774         atomic_inc(&stor_device->num_outstanding_req);
 775
 776         return ret;
 777 }
 778
 779 static void storvsc_get_ide_info(struct hv_device *dev, int *target, int *path)
 780 {
 781         *target =
 782                 dev->dev_instance.b[5] << 8 | dev->dev_instance.b[4];
 783
 784         *path =
 785                 dev->dev_instance.b[3] << 24 |
 786                 dev->dev_instance.b[2] << 16 |
 787                 dev->dev_instance.b[1] << 8  | dev->dev_instance.b[0];
 788 }
 789
 790
 791 static int storvsc_device_alloc(struct scsi_device *sdevice)
 792 {
 793         /*
 794          * This enables luns to be located sparsely. Otherwise, we may not
 795          * discovered them.
 796          */
 797         sdevice->sdev_bflags |= BLIST_SPARSELUN | BLIST_LARGELUN;
 798         return 0;
 799 }
 800
 801 static int storvsc_merge_bvec(struct request_queue *q,
 802                               struct bvec_merge_data *bmd, struct bio_vec *bvec)
 803 {
 804         /* checking done by caller. */
 805         return bvec->bv_len;
 806 }
 807
 808 static int storvsc_device_configure(struct scsi_device *sdevice)
 809 {
 810         scsi_adjust_queue_depth(sdevice, MSG_SIMPLE_TAG,
 811                                 STORVSC_MAX_IO_REQUESTS);
 812
 813         blk_queue_max_segment_size(sdevice->request_queue, PAGE_SIZE);
 814
 815         blk_queue_merge_bvec(sdevice->request_queue, storvsc_merge_bvec);
 816
 817         blk_queue_bounce_limit(sdevice->request_queue, BLK_BOUNCE_ANY);
 818
 819         return 0;
 820 }
 821
 822 static void destroy_bounce_buffer(struct scatterlist *sgl,
 823                                   unsigned int sg_count)
 824 {
 825         int i;
 826         struct page *page_buf;
 827
 828         for (i = 0; i < sg_count; i++) {
 829                 page_buf = sg_page((&sgl[i]));
 830                 if (page_buf != NULL)
 831                         __free_page(page_buf);
 832         }
 833
 834         kfree(sgl);
 835 }
 836
 837 static int do_bounce_buffer(struct scatterlist *sgl, unsigned int sg_count)
 838 {
 839         int i;
 840
 841         /* No need to check */
 842         if (sg_count < 2)
 843                 return -1;
 844
 845         /* We have at least 2 sg entries */
 846         for (i = 0; i < sg_count; i++) {
 847                 if (i == 0) {
 848                         /* make sure 1st one does not have hole */
 849                         if (sgl[i].offset + sgl[i].length != PAGE_SIZE)
 850                                 return i;
 851                 } else if (i == sg_count - 1) {
 852                         /* make sure last one does not have hole */
 853                         if (sgl[i].offset != 0)
 854                                 return i;
 855                 } else {
 856                         /* make sure no hole in the middle */
 857                         if (sgl[i].length != PAGE_SIZE || sgl[i].offset != 0)
 858                                 return i;
 859                 }
 860         }
 861         return -1;
 862 }
 863
 864 static struct scatterlist *create_bounce_buffer(struct scatterlist *sgl,
 865                                                 unsigned int sg_count,
 866                                                 unsigned int len)
 867 {
 868         int i;
 869         int num_pages;
 870         struct scatterlist *bounce_sgl;
 871         struct page *page_buf;
 872
 873         num_pages = ALIGN(len, PAGE_SIZE) >> PAGE_SHIFT;
 874
 875         bounce_sgl = kcalloc(num_pages, sizeof(struct scatterlist), GFP_ATOMIC);
 876         if (!bounce_sgl)
 877                 return NULL;
 878
 879         for (i = 0; i < num_pages; i++) {
 880                 page_buf = alloc_page(GFP_ATOMIC);
 881                 if (!page_buf)
 882                         goto cleanup;
 883                 sg_set_page(&bounce_sgl[i], page_buf, 0, 0);
 884         }
 885
 886         return bounce_sgl;
 887
 888 cleanup:
 889         destroy_bounce_buffer(bounce_sgl, num_pages);
 890         return NULL;
 891 }
 892
 893
 894 /* Assume the original sgl has enough room */
 895 static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl,
 896                                             struct scatterlist *bounce_sgl,
 897                                             unsigned int orig_sgl_count)
 898 {
 899         int i;
 900         int j = 0;
 901         unsigned long src, dest;
 902         unsigned int srclen, destlen, copylen;
 903         unsigned int total_copied = 0;
 904         unsigned long bounce_addr = 0;
 905         unsigned long dest_addr = 0;
 906         unsigned long flags;
 907
 908         local_irq_save(flags);
 909
 910         for (i = 0; i < orig_sgl_count; i++) {
 911                 dest_addr = (unsigned long)kmap_atomic(sg_page((&orig_sgl[i])),
 912                                         KM_IRQ0) + orig_sgl[i].offset;
 913                 dest = dest_addr;
 914                 destlen = orig_sgl[i].length;
 915
 916                 if (bounce_addr == 0)
 917                         bounce_addr =
 918                         (unsigned long)kmap_atomic(sg_page((&bounce_sgl[j])),
 919                                                         KM_IRQ0);
 920
 921                 while (destlen) {
 922                         src = bounce_addr + bounce_sgl[j].offset;
 923                         srclen = bounce_sgl[j].length - bounce_sgl[j].offset;
 924
 925                         copylen = min(srclen, destlen);
 926                         memcpy((void *)dest, (void *)src, copylen);
 927
 928                         total_copied += copylen;
 929                         bounce_sgl[j].offset += copylen;
 930                         destlen -= copylen;
 931                         dest += copylen;
 932
 933                         if (bounce_sgl[j].offset == bounce_sgl[j].length) {
 934                                 /* full */
 935                                 kunmap_atomic((void *)bounce_addr, KM_IRQ0);
 936                                 j++;
 937
 938                                 /* if we need to use another bounce buffer */
 939                                 if (destlen || i != orig_sgl_count - 1)
 940                                         bounce_addr =
 941                                         (unsigned long)kmap_atomic(
 942                                         sg_page((&bounce_sgl[j])), KM_IRQ0);
 943                         } else if (destlen == 0 && i == orig_sgl_count - 1) {
 944                                 /* unmap the last bounce that is < PAGE_SIZE */
 945                                 kunmap_atomic((void *)bounce_addr, KM_IRQ0);
 946                         }
 947                 }
 948
 949                 kunmap_atomic((void *)(dest_addr - orig_sgl[i].offset),
 950                               KM_IRQ0);
 951         }
 952
 953         local_irq_restore(flags);
 954
 955         return total_copied;
 956 }
 957
 958
 959 /* Assume the bounce_sgl has enough room ie using the create_bounce_buffer() */
 960 static unsigned int copy_to_bounce_buffer(struct scatterlist *orig_sgl,
 961                                           struct scatterlist *bounce_sgl,
 962                                           unsigned int orig_sgl_count)
 963 {
 964         int i;
 965         int j = 0;
 966         unsigned long src, dest;
 967         unsigned int srclen, destlen, copylen;
 968         unsigned int total_copied = 0;
 969         unsigned long bounce_addr = 0;
 970         unsigned long src_addr = 0;
 971         unsigned long flags;
 972
 973         local_irq_save(flags);
 974
 975         for (i = 0; i < orig_sgl_count; i++) {
 976                 src_addr = (unsigned long)kmap_atomic(sg_page((&orig_sgl[i])),
 977                                 KM_IRQ0) + orig_sgl[i].offset;
 978                 src = src_addr;
 979                 srclen = orig_sgl[i].length;
 980
 981                 if (bounce_addr == 0)
 982                         bounce_addr =
 983                         (unsigned long)kmap_atomic(sg_page((&bounce_sgl[j])),
 984                                                 KM_IRQ0);
 985
 986                 while (srclen) {
 987                         /* assume bounce offset always == 0 */
 988                         dest = bounce_addr + bounce_sgl[j].length;
 989                         destlen = PAGE_SIZE - bounce_sgl[j].length;
 990
 991                         copylen = min(srclen, destlen);
 992                         memcpy((void *)dest, (void *)src, copylen);
 993
 994                         total_copied += copylen;
 995                         bounce_sgl[j].length += copylen;
 996                         srclen -= copylen;
 997                         src += copylen;
 998
 999                         if (bounce_sgl[j].length == PAGE_SIZE) {
1000                                 /* full..move to next entry */
1001                                 kunmap_atomic((void *)bounce_addr, KM_IRQ0);
1002                                 j++;
1003
1004                                 /* if we need to use another bounce buffer */
1005                                 if (srclen || i != orig_sgl_count - 1)
1006                                         bounce_addr =
1007                                         (unsigned long)kmap_atomic(
1008                                         sg_page((&bounce_sgl[j])), KM_IRQ0);
1009
1010                         } else if (srclen == 0 && i == orig_sgl_count - 1) {
1011                                 /* unmap the last bounce that is < PAGE_SIZE */
1012                                 kunmap_atomic((void *)bounce_addr, KM_IRQ0);
1013                         }
1014                 }
1015
1016                 kunmap_atomic((void *)(src_addr - orig_sgl[i].offset), KM_IRQ0);
1017         }
1018
1019         local_irq_restore(flags);
1020
1021         return total_copied;
1022 }
1023
1024
1025 static int storvsc_remove(struct hv_device *dev)
1026 {
1027         struct storvsc_device *stor_device = hv_get_drvdata(dev);
1028         struct Scsi_Host *host = stor_device->host;
1029         struct hv_host_device *host_dev = shost_priv(host);
1030
1031         scsi_remove_host(host);
1032
1033         scsi_host_put(host);
1034
1035         storvsc_dev_remove(dev);
1036         if (host_dev->request_pool) {
1037                 mempool_destroy(host_dev->request_mempool);
1038                 kmem_cache_destroy(host_dev->request_pool);
1039                 host_dev->request_pool = NULL;
1040                 host_dev->request_mempool = NULL;
1041         }
1042         return 0;
1043 }
1044
1045
1046 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
1047                            sector_t capacity, int *info)
1048 {
1049         sector_t nsect = capacity;
1050         sector_t cylinders = nsect;
1051         int heads, sectors_pt;
1052
1053         /*
1054          * We are making up these values; let us keep it simple.
1055          */
1056         heads = 0xff;
1057         sectors_pt = 0x3f;      /* Sectors per track */
1058         sector_div(cylinders, heads * sectors_pt);
1059         if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
1060                 cylinders = 0xffff;
1061
1062         info[0] = heads;
1063         info[1] = sectors_pt;
1064         info[2] = (int)cylinders;
1065
1066         return 0;
1067 }
1068
1069 static int storvsc_host_reset(struct hv_device *device)
1070 {
1071         struct storvsc_device *stor_device;
1072         struct hv_storvsc_request *request;
1073         struct vstor_packet *vstor_packet;
1074         int ret, t;
1075
1076
1077         stor_device = get_out_stor_device(device);
1078         if (!stor_device)
1079                 return FAILED;
1080
1081         request = &stor_device->reset_request;
1082         vstor_packet = &request->vstor_packet;
1083
1084         init_completion(&request->wait_event);
1085
1086         vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
1087         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
1088         vstor_packet->vm_srb.path_id = stor_device->path_id;
1089
1090         ret = vmbus_sendpacket(device->channel, vstor_packet,
1091                                sizeof(struct vstor_packet),
1092                                (unsigned long)&stor_device->reset_request,
1093                                VM_PKT_DATA_INBAND,
1094                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
1095         if (ret != 0)
1096                 return FAILED;
1097
1098         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
1099         if (t == 0)
1100                 return TIMEOUT_ERROR;
1101
1102
1103         /*
1104          * At this point, all outstanding requests in the adapter
1105          * should have been flushed out and return to us
1106          */
1107
1108         return SUCCESS;
1109 }
1110
1111
1112 /*
1113  * storvsc_host_reset_handler - Reset the scsi HBA
1114  */
1115 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
1116 {
1117         struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1118         struct hv_device *dev = host_dev->dev;
1119
1120         return storvsc_host_reset(dev);
1121 }
1122
1123
1124 /*
1125  * storvsc_command_completion - Command completion processing
1126  */
1127 static void storvsc_command_completion(struct hv_storvsc_request *request)
1128 {
1129         struct storvsc_cmd_request *cmd_request =
1130                 (struct storvsc_cmd_request *)request->context;
1131         struct scsi_cmnd *scmnd = cmd_request->cmd;
1132         struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
1133         void (*scsi_done_fn)(struct scsi_cmnd *);
1134         struct scsi_sense_hdr sense_hdr;
1135         struct vmscsi_request *vm_srb;
1136         struct storvsc_scan_work *wrk;
1137
1138         vm_srb = &request->vstor_packet.vm_srb;
1139         if (cmd_request->bounce_sgl_count) {
1140                 if (vm_srb->data_in == READ_TYPE) {
1141                         copy_from_bounce_buffer(scsi_sglist(scmnd),
1142                                         cmd_request->bounce_sgl,
1143                                         scsi_sg_count(scmnd));
1144                         destroy_bounce_buffer(cmd_request->bounce_sgl,
1145                                         cmd_request->bounce_sgl_count);
1146                 }
1147         }
1148
1149         /*
1150          * If there is an error; offline the device since all
1151          * error recovery strategies would have already been
1152          * deployed on the host side.
1153          */
1154         if (vm_srb->srb_status == 0x4)
1155                 scmnd->result = DID_TARGET_FAILURE << 16;
1156         else
1157                 scmnd->result = vm_srb->scsi_status;
1158
1159         /*
1160          * If the LUN is invalid; remove the device.
1161          */
1162         if (vm_srb->srb_status == 0x20) {
1163                 struct storvsc_device *stor_dev;
1164                 struct hv_device *dev = host_dev->dev;
1165                 struct Scsi_Host *host;
1166
1167                 stor_dev = get_in_stor_device(dev);
1168                 host = stor_dev->host;
1169
1170                 wrk = kmalloc(sizeof(struct storvsc_scan_work),
1171                                 GFP_ATOMIC);
1172                 if (!wrk) {
1173                         scmnd->result = DID_TARGET_FAILURE << 16;
1174                 } else {
1175                         wrk->host = host;
1176                         wrk->lun = vm_srb->lun;
1177                         INIT_WORK(&wrk->work, storvsc_remove_lun);
1178                         schedule_work(&wrk->work);
1179                 }
1180         }
1181
1182         if (scmnd->result) {
1183                 if (scsi_normalize_sense(scmnd->sense_buffer,
1184                                 SCSI_SENSE_BUFFERSIZE, &sense_hdr))
1185                         scsi_print_sense_hdr("storvsc", &sense_hdr);
1186         }
1187
1188         scsi_set_resid(scmnd,
1189                 request->data_buffer.len -
1190                 vm_srb->data_transfer_length);
1191
1192         scsi_done_fn = scmnd->scsi_done;
1193
1194         scmnd->host_scribble = NULL;
1195         scmnd->scsi_done = NULL;
1196
1197         scsi_done_fn(scmnd);
1198
1199         mempool_free(cmd_request, host_dev->request_mempool);
1200 }
1201
1202 static bool storvsc_check_scsi_cmd(struct scsi_cmnd *scmnd)
1203 {
1204         bool allowed = true;
1205         u8 scsi_op = scmnd->cmnd[0];
1206
1207         switch (scsi_op) {
1208         /* smartd sends this command, which will offline the device */
1209         case SET_WINDOW:
1210                 scmnd->result = ILLEGAL_REQUEST << 16;
1211                 allowed = false;
1212                 break;
1213         default:
1214                 break;
1215         }
1216         return allowed;
1217 }
1218
1219 /*
1220  * storvsc_queuecommand - Initiate command processing
1221  */
1222 static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
1223 {
1224         int ret;
1225         struct hv_host_device *host_dev = shost_priv(host);
1226         struct hv_device *dev = host_dev->dev;
1227         struct hv_storvsc_request *request;
1228         struct storvsc_cmd_request *cmd_request;
1229         unsigned int request_size = 0;
1230         int i;
1231         struct scatterlist *sgl;
1232         unsigned int sg_count = 0;
1233         struct vmscsi_request *vm_srb;
1234
1235         if (storvsc_check_scsi_cmd(scmnd) == false) {
1236                 scmnd->scsi_done(scmnd);
1237                 return 0;
1238         }
1239
1240         /* If retrying, no need to prep the cmd */
1241         if (scmnd->host_scribble) {
1242
1243                 cmd_request =
1244                         (struct storvsc_cmd_request *)scmnd->host_scribble;
1245
1246                 goto retry_request;
1247         }
1248
1249         request_size = sizeof(struct storvsc_cmd_request);
1250
1251         cmd_request = mempool_alloc(host_dev->request_mempool,
1252                                        GFP_ATOMIC);
1253         if (!cmd_request)
1254                 return SCSI_MLQUEUE_DEVICE_BUSY;
1255
1256         memset(cmd_request, 0, sizeof(struct storvsc_cmd_request));
1257
1258         /* Setup the cmd request */
1259         cmd_request->bounce_sgl_count = 0;
1260         cmd_request->bounce_sgl = NULL;
1261         cmd_request->cmd = scmnd;
1262
1263         scmnd->host_scribble = (unsigned char *)cmd_request;
1264
1265         request = &cmd_request->request;
1266         vm_srb = &request->vstor_packet.vm_srb;
1267
1268
1269         /* Build the SRB */
1270         switch (scmnd->sc_data_direction) {
1271         case DMA_TO_DEVICE:
1272                 vm_srb->data_in = WRITE_TYPE;
1273                 break;
1274         case DMA_FROM_DEVICE:
1275                 vm_srb->data_in = READ_TYPE;
1276                 break;
1277         default:
1278                 vm_srb->data_in = UNKNOWN_TYPE;
1279                 break;
1280         }
1281
1282         request->on_io_completion = storvsc_command_completion;
1283         request->context = cmd_request;/* scmnd; */
1284
1285         vm_srb->port_number = host_dev->port;
1286         vm_srb->path_id = scmnd->device->channel;
1287         vm_srb->target_id = scmnd->device->id;
1288         vm_srb->lun = scmnd->device->lun;
1289
1290         vm_srb->cdb_length = scmnd->cmd_len;
1291
1292         memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
1293
1294         request->sense_buffer = scmnd->sense_buffer;
1295
1296
1297         request->data_buffer.len = scsi_bufflen(scmnd);
1298         if (scsi_sg_count(scmnd)) {
1299                 sgl = (struct scatterlist *)scsi_sglist(scmnd);
1300                 sg_count = scsi_sg_count(scmnd);
1301
1302                 /* check if we need to bounce the sgl */
1303                 if (do_bounce_buffer(sgl, scsi_sg_count(scmnd)) != -1) {
1304                         cmd_request->bounce_sgl =
1305                                 create_bounce_buffer(sgl, scsi_sg_count(scmnd),
1306                                                      scsi_bufflen(scmnd));
1307                         if (!cmd_request->bounce_sgl) {
1308                                 scmnd->host_scribble = NULL;
1309                                 mempool_free(cmd_request,
1310                                                 host_dev->request_mempool);
1311
1312                                 return SCSI_MLQUEUE_HOST_BUSY;
1313                         }
1314
1315                         cmd_request->bounce_sgl_count =
1316                                 ALIGN(scsi_bufflen(scmnd), PAGE_SIZE) >>
1317                                         PAGE_SHIFT;
1318
1319                         if (vm_srb->data_in == WRITE_TYPE)
1320                                 copy_to_bounce_buffer(sgl,
1321                                         cmd_request->bounce_sgl,
1322                                         scsi_sg_count(scmnd));
1323
1324                         sgl = cmd_request->bounce_sgl;
1325                         sg_count = cmd_request->bounce_sgl_count;
1326                 }
1327
1328                 request->data_buffer.offset = sgl[0].offset;
1329
1330                 for (i = 0; i < sg_count; i++)
1331                         request->data_buffer.pfn_array[i] =
1332                                 page_to_pfn(sg_page((&sgl[i])));
1333
1334         } else if (scsi_sglist(scmnd)) {
1335                 request->data_buffer.offset =
1336                         virt_to_phys(scsi_sglist(scmnd)) & (PAGE_SIZE-1);
1337                 request->data_buffer.pfn_array[0] =
1338                         virt_to_phys(scsi_sglist(scmnd)) >> PAGE_SHIFT;
1339         }
1340
1341 retry_request:
1342         /* Invokes the vsc to start an IO */
1343         ret = storvsc_do_io(dev, &cmd_request->request);
1344
1345         if (ret == -EAGAIN) {
1346                 /* no more space */
1347
1348                 if (cmd_request->bounce_sgl_count)
1349                         destroy_bounce_buffer(cmd_request->bounce_sgl,
1350                                         cmd_request->bounce_sgl_count);
1351
1352                 mempool_free(cmd_request, host_dev->request_mempool);
1353
1354                 scmnd->host_scribble = NULL;
1355
1356                 ret = SCSI_MLQUEUE_DEVICE_BUSY;
1357         }
1358
1359         return ret;
1360 }
1361
1362 /* Scsi driver */
1363 static struct scsi_host_template scsi_driver = {
1364         .module =               THIS_MODULE,
1365         .name =                 "storvsc_host_t",
1366         .bios_param =           storvsc_get_chs,
1367         .queuecommand =         storvsc_queuecommand,
1368         .eh_host_reset_handler =        storvsc_host_reset_handler,
1369         .slave_alloc =          storvsc_device_alloc,
1370         .slave_configure =      storvsc_device_configure,
1371         .cmd_per_lun =          1,
1372         /* 64 max_queue * 1 target */
1373         .can_queue =            STORVSC_MAX_IO_REQUESTS*STORVSC_MAX_TARGETS,
1374         .this_id =              -1,
1375         /* no use setting to 0 since ll_blk_rw reset it to 1 */
1376         /* currently 32 */
1377         .sg_tablesize =         MAX_MULTIPAGE_BUFFER_COUNT,
1378         /*
1379          * ENABLE_CLUSTERING allows mutiple physically contig bio_vecs to merge
1380          * into 1 sg element. If set, we must limit the max_segment_size to
1381          * PAGE_SIZE, otherwise we may get 1 sg element that represents
1382          * multiple
1383          */
1384         /* physically contig pfns (ie sg[x].length > PAGE_SIZE). */
1385         .use_clustering =       ENABLE_CLUSTERING,
1386         /* Make sure we dont get a sg segment crosses a page boundary */
1387         .dma_boundary =         PAGE_SIZE-1,
1388 };
1389
1390 enum {
1391         SCSI_GUID,
1392         IDE_GUID,
1393 };
1394
1395 static const struct hv_vmbus_device_id id_table[] = {
1396         /* SCSI guid */
1397         { VMBUS_DEVICE(0xd9, 0x63, 0x61, 0xba, 0xa1, 0x04, 0x29, 0x4d,
1398                        0xb6, 0x05, 0x72, 0xe2, 0xff, 0xb1, 0xdc, 0x7f)
1399           .driver_data = SCSI_GUID },
1400         /* IDE guid */
1401         { VMBUS_DEVICE(0x32, 0x26, 0x41, 0x32, 0xcb, 0x86, 0xa2, 0x44,
1402                        0x9b, 0x5c, 0x50, 0xd1, 0x41, 0x73, 0x54, 0xf5)
1403           .driver_data = IDE_GUID },
1404         { },
1405 };
1406
1407 MODULE_DEVICE_TABLE(vmbus, id_table);
1408
1409
1410 /*
1411  * storvsc_probe - Add a new device for this driver
1412  */
1413
1414 static int storvsc_probe(struct hv_device *device,
1415                         const struct hv_vmbus_device_id *dev_id)
1416 {
1417         int ret;
1418         int number = STORVSC_MIN_BUF_NR;
1419         struct Scsi_Host *host;
1420         struct hv_host_device *host_dev;
1421         bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
1422         int path = 0;
1423         int target = 0;
1424         struct storvsc_device *stor_device;
1425
1426         host = scsi_host_alloc(&scsi_driver,
1427                                sizeof(struct hv_host_device));
1428         if (!host)
1429                 return -ENOMEM;
1430
1431         host_dev = shost_priv(host);
1432         memset(host_dev, 0, sizeof(struct hv_host_device));
1433
1434         host_dev->port = host->host_no;
1435         host_dev->dev = device;
1436
1437         host_dev->request_pool =
1438                                 kmem_cache_create(dev_name(&device->device),
1439                                         sizeof(struct storvsc_cmd_request), 0,
1440                                         SLAB_HWCACHE_ALIGN, NULL);
1441
1442         if (!host_dev->request_pool) {
1443                 scsi_host_put(host);
1444                 return -ENOMEM;
1445         }
1446
1447         host_dev->request_mempool = mempool_create(number, mempool_alloc_slab,
1448                                                 mempool_free_slab,
1449                                                 host_dev->request_pool);
1450
1451         if (!host_dev->request_mempool) {
1452                 ret = -ENOMEM;
1453                 goto err_out0;
1454         }
1455
1456         stor_device = kzalloc(sizeof(struct storvsc_device), GFP_KERNEL);
1457         if (!stor_device) {
1458                 ret = -ENOMEM;
1459                 goto err_out1;
1460         }
1461
1462         stor_device->destroy = false;
1463         init_waitqueue_head(&stor_device->waiting_to_drain);
1464         stor_device->device = device;
1465         stor_device->host = host;
1466         hv_set_drvdata(device, stor_device);
1467
1468         stor_device->port_number = host->host_no;
1469         ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size);
1470         if (ret)
1471                 goto err_out2;
1472
1473         if (dev_is_ide)
1474                 storvsc_get_ide_info(device, &target, &path);
1475
1476         host_dev->path = stor_device->path_id;
1477         host_dev->target = stor_device->target_id;
1478
1479         /* max # of devices per target */
1480         host->max_lun = STORVSC_MAX_LUNS_PER_TARGET;
1481         /* max # of targets per channel */
1482         host->max_id = STORVSC_MAX_TARGETS;
1483         /* max # of channels */
1484         host->max_channel = STORVSC_MAX_CHANNELS - 1;
1485         /* max cmd length */
1486         host->max_cmd_len = STORVSC_MAX_CMD_LEN;
1487
1488         /* Register the HBA and start the scsi bus scan */
1489         ret = scsi_add_host(host, &device->device);
1490         if (ret != 0)
1491                 goto err_out3;
1492
1493         if (!dev_is_ide) {
1494                 scsi_scan_host(host);
1495                 return 0;
1496         }
1497         ret = scsi_add_device(host, 0, target, 0);
1498         if (ret) {
1499                 scsi_remove_host(host);
1500                 goto err_out3;
1501         }
1502         return 0;
1503
1504 err_out3:
1505         /*
1506          * Once we have connected with the host, we would need to
1507          * to invoke storvsc_dev_remove() to rollback this state and
1508          * this call also frees up the stor_device; hence the jump around
1509          * err_out2 label.
1510          */
1511         storvsc_dev_remove(device);
1512         goto err_out1;
1513
1514 err_out2:
1515         kfree(stor_device);
1516
1517 err_out1:
1518         mempool_destroy(host_dev->request_mempool);
1519
1520 err_out0:
1521         kmem_cache_destroy(host_dev->request_pool);
1522         scsi_host_put(host);
1523         return ret;
1524 }
1525
1526 /* The one and only one */
1527
1528 static struct hv_driver storvsc_drv = {
1529         .name = KBUILD_MODNAME,
1530         .id_table = id_table,
1531         .probe = storvsc_probe,
1532         .remove = storvsc_remove,
1533 };
1534
1535 static int __init storvsc_drv_init(void)
1536 {
1537         u32 max_outstanding_req_per_channel;
1538
1539         /*
1540          * Divide the ring buffer data size (which is 1 page less
1541          * than the ring buffer size since that page is reserved for
1542          * the ring buffer indices) by the max request size (which is
1543          * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
1544          */
1545         max_outstanding_req_per_channel =
1546                 ((storvsc_ringbuffer_size - PAGE_SIZE) /
1547                 ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
1548                 sizeof(struct vstor_packet) + sizeof(u64),
1549                 sizeof(u64)));
1550
1551         if (max_outstanding_req_per_channel <
1552             STORVSC_MAX_IO_REQUESTS)
1553                 return -EINVAL;
1554
1555         return vmbus_driver_register(&storvsc_drv);
1556 }
1557
1558 static void __exit storvsc_drv_exit(void)
1559 {
1560         vmbus_driver_unregister(&storvsc_drv);
1561 }
1562
1563 MODULE_LICENSE("GPL");
1564 MODULE_VERSION(HV_DRV_VERSION);
1565 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
1566 module_init(storvsc_drv_init);
1567 module_exit(storvsc_drv_exit);