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 #include <linux/init.h>
  23 #include <linux/slab.h>
  24 #include <linux/module.h>
  25 #include <linux/device.h>
  26 #include <linux/blkdev.h>
  27 #include <scsi/scsi.h>
  28 #include <scsi/scsi_cmnd.h>
  29 #include <scsi/scsi_host.h>
  30 #include <scsi/scsi_device.h>
  31 #include <scsi/scsi_tcq.h>
  32 #include <scsi/scsi_eh.h>
  33 #include <scsi/scsi_devinfo.h>
  34 #include <scsi/scsi_dbg.h>
  35
  36 #include "hyperv.h"
  37 #include "hyperv_storage.h"
  38
  39 static int storvsc_ringbuffer_size = STORVSC_RING_BUFFER_SIZE;
  40
  41 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
  42 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
  43
  44 struct hv_host_device {
  45         struct hv_device *dev;
  46         struct kmem_cache *request_pool;
  47         unsigned int port;
  48         unsigned char path;
  49         unsigned char target;
  50 };
  51
  52 struct storvsc_cmd_request {
  53         struct list_head entry;
  54         struct scsi_cmnd *cmd;
  55
  56         unsigned int bounce_sgl_count;
  57         struct scatterlist *bounce_sgl;
  58
  59         struct hv_storvsc_request request;
  60 };
  61
  62 static void storvsc_get_ide_info(struct hv_device *dev, int *target, int *path)
  63 {
  64         *target =
  65                 dev->dev_instance.b[5] << 8 | dev->dev_instance.b[4];
  66
  67         *path =
  68                 dev->dev_instance.b[3] << 24 |
  69                 dev->dev_instance.b[2] << 16 |
  70                 dev->dev_instance.b[1] << 8  | dev->dev_instance.b[0];
  71 }
  72
  73
  74 static int storvsc_device_alloc(struct scsi_device *sdevice)
  75 {
  76         /*
  77          * This enables luns to be located sparsely. Otherwise, we may not
  78          * discovered them.
  79          */
  80         sdevice->sdev_bflags |= BLIST_SPARSELUN | BLIST_LARGELUN;
  81         return 0;
  82 }
  83
  84 static int storvsc_merge_bvec(struct request_queue *q,
  85                               struct bvec_merge_data *bmd, struct bio_vec *bvec)
  86 {
  87         /* checking done by caller. */
  88         return bvec->bv_len;
  89 }
  90
  91 static int storvsc_device_configure(struct scsi_device *sdevice)
  92 {
  93         scsi_adjust_queue_depth(sdevice, MSG_SIMPLE_TAG,
  94                                 STORVSC_MAX_IO_REQUESTS);
  95
  96         blk_queue_max_segment_size(sdevice->request_queue, PAGE_SIZE);
  97
  98         blk_queue_merge_bvec(sdevice->request_queue, storvsc_merge_bvec);
  99
 100         blk_queue_bounce_limit(sdevice->request_queue, BLK_BOUNCE_ANY);
 101
 102         return 0;
 103 }
 104
 105 static void destroy_bounce_buffer(struct scatterlist *sgl,
 106                                   unsigned int sg_count)
 107 {
 108         int i;
 109         struct page *page_buf;
 110
 111         for (i = 0; i < sg_count; i++) {
 112                 page_buf = sg_page((&sgl[i]));
 113                 if (page_buf != NULL)
 114                         __free_page(page_buf);
 115         }
 116
 117         kfree(sgl);
 118 }
 119
 120 static int do_bounce_buffer(struct scatterlist *sgl, unsigned int sg_count)
 121 {
 122         int i;
 123
 124         /* No need to check */
 125         if (sg_count < 2)
 126                 return -1;
 127
 128         /* We have at least 2 sg entries */
 129         for (i = 0; i < sg_count; i++) {
 130                 if (i == 0) {
 131                         /* make sure 1st one does not have hole */
 132                         if (sgl[i].offset + sgl[i].length != PAGE_SIZE)
 133                                 return i;
 134                 } else if (i == sg_count - 1) {
 135                         /* make sure last one does not have hole */
 136                         if (sgl[i].offset != 0)
 137                                 return i;
 138                 } else {
 139                         /* make sure no hole in the middle */
 140                         if (sgl[i].length != PAGE_SIZE || sgl[i].offset != 0)
 141                                 return i;
 142                 }
 143         }
 144         return -1;
 145 }
 146
 147 static struct scatterlist *create_bounce_buffer(struct scatterlist *sgl,
 148                                                 unsigned int sg_count,
 149                                                 unsigned int len)
 150 {
 151         int i;
 152         int num_pages;
 153         struct scatterlist *bounce_sgl;
 154         struct page *page_buf;
 155
 156         num_pages = ALIGN(len, PAGE_SIZE) >> PAGE_SHIFT;
 157
 158         bounce_sgl = kcalloc(num_pages, sizeof(struct scatterlist), GFP_ATOMIC);
 159         if (!bounce_sgl)
 160                 return NULL;
 161
 162         for (i = 0; i < num_pages; i++) {
 163                 page_buf = alloc_page(GFP_ATOMIC);
 164                 if (!page_buf)
 165                         goto cleanup;
 166                 sg_set_page(&bounce_sgl[i], page_buf, 0, 0);
 167         }
 168
 169         return bounce_sgl;
 170
 171 cleanup:
 172         destroy_bounce_buffer(bounce_sgl, num_pages);
 173         return NULL;
 174 }
 175
 176
 177 /* Assume the original sgl has enough room */
 178 static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl,
 179                                             struct scatterlist *bounce_sgl,
 180                                             unsigned int orig_sgl_count)
 181 {
 182         int i;
 183         int j = 0;
 184         unsigned long src, dest;
 185         unsigned int srclen, destlen, copylen;
 186         unsigned int total_copied = 0;
 187         unsigned long bounce_addr = 0;
 188         unsigned long dest_addr = 0;
 189         unsigned long flags;
 190
 191         local_irq_save(flags);
 192
 193         for (i = 0; i < orig_sgl_count; i++) {
 194                 dest_addr = (unsigned long)kmap_atomic(sg_page((&orig_sgl[i])),
 195                                         KM_IRQ0) + orig_sgl[i].offset;
 196                 dest = dest_addr;
 197                 destlen = orig_sgl[i].length;
 198
 199                 if (bounce_addr == 0)
 200                         bounce_addr =
 201                         (unsigned long)kmap_atomic(sg_page((&bounce_sgl[j])),
 202                                                         KM_IRQ0);
 203
 204                 while (destlen) {
 205                         src = bounce_addr + bounce_sgl[j].offset;
 206                         srclen = bounce_sgl[j].length - bounce_sgl[j].offset;
 207
 208                         copylen = min(srclen, destlen);
 209                         memcpy((void *)dest, (void *)src, copylen);
 210
 211                         total_copied += copylen;
 212                         bounce_sgl[j].offset += copylen;
 213                         destlen -= copylen;
 214                         dest += copylen;
 215
 216                         if (bounce_sgl[j].offset == bounce_sgl[j].length) {
 217                                 /* full */
 218                                 kunmap_atomic((void *)bounce_addr, KM_IRQ0);
 219                                 j++;
 220
 221                                 /* if we need to use another bounce buffer */
 222                                 if (destlen || i != orig_sgl_count - 1)
 223                                         bounce_addr =
 224                                         (unsigned long)kmap_atomic(
 225                                         sg_page((&bounce_sgl[j])), KM_IRQ0);
 226                         } else if (destlen == 0 && i == orig_sgl_count - 1) {
 227                                 /* unmap the last bounce that is < PAGE_SIZE */
 228                                 kunmap_atomic((void *)bounce_addr, KM_IRQ0);
 229                         }
 230                 }
 231
 232                 kunmap_atomic((void *)(dest_addr - orig_sgl[i].offset),
 233                               KM_IRQ0);
 234         }
 235
 236         local_irq_restore(flags);
 237
 238         return total_copied;
 239 }
 240
 241
 242 /* Assume the bounce_sgl has enough room ie using the create_bounce_buffer() */
 243 static unsigned int copy_to_bounce_buffer(struct scatterlist *orig_sgl,
 244                                           struct scatterlist *bounce_sgl,
 245                                           unsigned int orig_sgl_count)
 246 {
 247         int i;
 248         int j = 0;
 249         unsigned long src, dest;
 250         unsigned int srclen, destlen, copylen;
 251         unsigned int total_copied = 0;
 252         unsigned long bounce_addr = 0;
 253         unsigned long src_addr = 0;
 254         unsigned long flags;
 255
 256         local_irq_save(flags);
 257
 258         for (i = 0; i < orig_sgl_count; i++) {
 259                 src_addr = (unsigned long)kmap_atomic(sg_page((&orig_sgl[i])),
 260                                 KM_IRQ0) + orig_sgl[i].offset;
 261                 src = src_addr;
 262                 srclen = orig_sgl[i].length;
 263
 264                 if (bounce_addr == 0)
 265                         bounce_addr =
 266                         (unsigned long)kmap_atomic(sg_page((&bounce_sgl[j])),
 267                                                 KM_IRQ0);
 268
 269                 while (srclen) {
 270                         /* assume bounce offset always == 0 */
 271                         dest = bounce_addr + bounce_sgl[j].length;
 272                         destlen = PAGE_SIZE - bounce_sgl[j].length;
 273
 274                         copylen = min(srclen, destlen);
 275                         memcpy((void *)dest, (void *)src, copylen);
 276
 277                         total_copied += copylen;
 278                         bounce_sgl[j].length += copylen;
 279                         srclen -= copylen;
 280                         src += copylen;
 281
 282                         if (bounce_sgl[j].length == PAGE_SIZE) {
 283                                 /* full..move to next entry */
 284                                 kunmap_atomic((void *)bounce_addr, KM_IRQ0);
 285                                 j++;
 286
 287                                 /* if we need to use another bounce buffer */
 288                                 if (srclen || i != orig_sgl_count - 1)
 289                                         bounce_addr =
 290                                         (unsigned long)kmap_atomic(
 291                                         sg_page((&bounce_sgl[j])), KM_IRQ0);
 292
 293                         } else if (srclen == 0 && i == orig_sgl_count - 1) {
 294                                 /* unmap the last bounce that is < PAGE_SIZE */
 295                                 kunmap_atomic((void *)bounce_addr, KM_IRQ0);
 296                         }
 297                 }
 298
 299                 kunmap_atomic((void *)(src_addr - orig_sgl[i].offset), KM_IRQ0);
 300         }
 301
 302         local_irq_restore(flags);
 303
 304         return total_copied;
 305 }
 306
 307
 308 static int storvsc_remove(struct hv_device *dev)
 309 {
 310         struct Scsi_Host *host = dev_get_drvdata(&dev->device);
 311         struct hv_host_device *host_dev =
 312                         (struct hv_host_device *)host->hostdata;
 313
 314         scsi_remove_host(host);
 315
 316         scsi_host_put(host);
 317
 318         storvsc_dev_remove(dev);
 319         if (host_dev->request_pool) {
 320                 kmem_cache_destroy(host_dev->request_pool);
 321                 host_dev->request_pool = NULL;
 322         }
 323         return 0;
 324 }
 325
 326
 327 static int storvsc_get_chs(struct scsi_device *sdev, struct block_device * bdev,
 328                            sector_t capacity, int *info)
 329 {
 330         sector_t nsect = capacity;
 331         sector_t cylinders = nsect;
 332         int heads, sectors_pt;
 333
 334         /*
 335          * We are making up these values; let us keep it simple.
 336          */
 337         heads = 0xff;
 338         sectors_pt = 0x3f;      /* Sectors per track */
 339         sector_div(cylinders, heads * sectors_pt);
 340         if ((sector_t)(cylinders + 1) * heads * sectors_pt < nsect)
 341                 cylinders = 0xffff;
 342
 343         info[0] = heads;
 344         info[1] = sectors_pt;
 345         info[2] = (int)cylinders;
 346
 347         return 0;
 348 }
 349
 350 static int storvsc_host_reset(struct hv_device *device)
 351 {
 352         struct storvsc_device *stor_device;
 353         struct hv_storvsc_request *request;
 354         struct vstor_packet *vstor_packet;
 355         int ret, t;
 356
 357
 358         stor_device = get_out_stor_device(device);
 359         if (!stor_device)
 360                 return -ENODEV;
 361
 362         request = &stor_device->reset_request;
 363         vstor_packet = &request->vstor_packet;
 364
 365         init_completion(&request->wait_event);
 366
 367         vstor_packet->operation = VSTOR_OPERATION_RESET_BUS;
 368         vstor_packet->flags = REQUEST_COMPLETION_FLAG;
 369         vstor_packet->vm_srb.path_id = stor_device->path_id;
 370
 371         ret = vmbus_sendpacket(device->channel, vstor_packet,
 372                                sizeof(struct vstor_packet),
 373                                (unsigned long)&stor_device->reset_request,
 374                                VM_PKT_DATA_INBAND,
 375                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 376         if (ret != 0)
 377                 goto cleanup;
 378
 379         t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
 380         if (t == 0) {
 381                 ret = -ETIMEDOUT;
 382                 goto cleanup;
 383         }
 384
 385
 386         /*
 387          * At this point, all outstanding requests in the adapter
 388          * should have been flushed out and return to us
 389          */
 390
 391 cleanup:
 392         return ret;
 393 }
 394
 395
 396 /*
 397  * storvsc_host_reset_handler - Reset the scsi HBA
 398  */
 399 static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
 400 {
 401         int ret;
 402         struct hv_host_device *host_dev =
 403                 (struct hv_host_device *)scmnd->device->host->hostdata;
 404         struct hv_device *dev = host_dev->dev;
 405
 406         ret = storvsc_host_reset(dev);
 407         if (ret != 0)
 408                 return ret;
 409
 410         return ret;
 411 }
 412
 413
 414 /*
 415  * storvsc_commmand_completion - Command completion processing
 416  */
 417 static void storvsc_commmand_completion(struct hv_storvsc_request *request)
 418 {
 419         struct storvsc_cmd_request *cmd_request =
 420                 (struct storvsc_cmd_request *)request->context;
 421         struct scsi_cmnd *scmnd = cmd_request->cmd;
 422         struct hv_host_device *host_dev =
 423                 (struct hv_host_device *)scmnd->device->host->hostdata;
 424         void (*scsi_done_fn)(struct scsi_cmnd *);
 425         struct scsi_sense_hdr sense_hdr;
 426         struct vmscsi_request *vm_srb;
 427
 428         if (cmd_request->bounce_sgl_count) {
 429
 430                 /* FIXME: We can optimize on writes by just skipping this */
 431                 copy_from_bounce_buffer(scsi_sglist(scmnd),
 432                                         cmd_request->bounce_sgl,
 433                                         scsi_sg_count(scmnd));
 434                 destroy_bounce_buffer(cmd_request->bounce_sgl,
 435                                       cmd_request->bounce_sgl_count);
 436         }
 437
 438         vm_srb = &request->vstor_packet.vm_srb;
 439         scmnd->result = vm_srb->scsi_status;
 440
 441         if (scmnd->result) {
 442                 if (scsi_normalize_sense(scmnd->sense_buffer,
 443                                 SCSI_SENSE_BUFFERSIZE, &sense_hdr))
 444                         scsi_print_sense_hdr("storvsc", &sense_hdr);
 445         }
 446
 447         scsi_set_resid(scmnd,
 448                 request->data_buffer.len -
 449                 vm_srb->data_transfer_length);
 450
 451         scsi_done_fn = scmnd->scsi_done;
 452
 453         scmnd->host_scribble = NULL;
 454         scmnd->scsi_done = NULL;
 455
 456         scsi_done_fn(scmnd);
 457
 458         kmem_cache_free(host_dev->request_pool, cmd_request);
 459 }
 460
 461
 462 /*
 463  * storvsc_queuecommand - Initiate command processing
 464  */
 465 static int storvsc_queuecommand_lck(struct scsi_cmnd *scmnd,
 466                                 void (*done)(struct scsi_cmnd *))
 467 {
 468         int ret;
 469         struct hv_host_device *host_dev =
 470                 (struct hv_host_device *)scmnd->device->host->hostdata;
 471         struct hv_device *dev = host_dev->dev;
 472         struct hv_storvsc_request *request;
 473         struct storvsc_cmd_request *cmd_request;
 474         unsigned int request_size = 0;
 475         int i;
 476         struct scatterlist *sgl;
 477         unsigned int sg_count = 0;
 478         struct vmscsi_request *vm_srb;
 479
 480
 481         /* If retrying, no need to prep the cmd */
 482         if (scmnd->host_scribble) {
 483
 484                 cmd_request =
 485                         (struct storvsc_cmd_request *)scmnd->host_scribble;
 486
 487                 goto retry_request;
 488         }
 489
 490         scmnd->scsi_done = done;
 491
 492         request_size = sizeof(struct storvsc_cmd_request);
 493
 494         cmd_request = kmem_cache_zalloc(host_dev->request_pool,
 495                                        GFP_ATOMIC);
 496         if (!cmd_request) {
 497                 scmnd->scsi_done = NULL;
 498                 return SCSI_MLQUEUE_DEVICE_BUSY;
 499         }
 500
 501         /* Setup the cmd request */
 502         cmd_request->bounce_sgl_count = 0;
 503         cmd_request->bounce_sgl = NULL;
 504         cmd_request->cmd = scmnd;
 505
 506         scmnd->host_scribble = (unsigned char *)cmd_request;
 507
 508         request = &cmd_request->request;
 509         vm_srb = &request->vstor_packet.vm_srb;
 510
 511
 512         /* Build the SRB */
 513         switch (scmnd->sc_data_direction) {
 514         case DMA_TO_DEVICE:
 515                 vm_srb->data_in = WRITE_TYPE;
 516                 break;
 517         case DMA_FROM_DEVICE:
 518                 vm_srb->data_in = READ_TYPE;
 519                 break;
 520         default:
 521                 vm_srb->data_in = UNKNOWN_TYPE;
 522                 break;
 523         }
 524
 525         request->on_io_completion = storvsc_commmand_completion;
 526         request->context = cmd_request;/* scmnd; */
 527
 528         vm_srb->port_number = host_dev->port;
 529         vm_srb->path_id = scmnd->device->channel;
 530         vm_srb->target_id = scmnd->device->id;
 531         vm_srb->lun = scmnd->device->lun;
 532
 533         vm_srb->cdb_length = scmnd->cmd_len;
 534
 535         memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
 536
 537         request->sense_buffer = scmnd->sense_buffer;
 538
 539
 540         request->data_buffer.len = scsi_bufflen(scmnd);
 541         if (scsi_sg_count(scmnd)) {
 542                 sgl = (struct scatterlist *)scsi_sglist(scmnd);
 543                 sg_count = scsi_sg_count(scmnd);
 544
 545                 /* check if we need to bounce the sgl */
 546                 if (do_bounce_buffer(sgl, scsi_sg_count(scmnd)) != -1) {
 547                         cmd_request->bounce_sgl =
 548                                 create_bounce_buffer(sgl, scsi_sg_count(scmnd),
 549                                                      scsi_bufflen(scmnd));
 550                         if (!cmd_request->bounce_sgl) {
 551                                 scmnd->scsi_done = NULL;
 552                                 scmnd->host_scribble = NULL;
 553                                 kmem_cache_free(host_dev->request_pool,
 554                                                 cmd_request);
 555
 556                                 return SCSI_MLQUEUE_HOST_BUSY;
 557                         }
 558
 559                         cmd_request->bounce_sgl_count =
 560                                 ALIGN(scsi_bufflen(scmnd), PAGE_SIZE) >>
 561                                         PAGE_SHIFT;
 562
 563                         /*
 564                          * FIXME: We can optimize on reads by just skipping
 565                          * this
 566                          */
 567                         copy_to_bounce_buffer(sgl, cmd_request->bounce_sgl,
 568                                               scsi_sg_count(scmnd));
 569
 570                         sgl = cmd_request->bounce_sgl;
 571                         sg_count = cmd_request->bounce_sgl_count;
 572                 }
 573
 574                 request->data_buffer.offset = sgl[0].offset;
 575
 576                 for (i = 0; i < sg_count; i++)
 577                         request->data_buffer.pfn_array[i] =
 578                                 page_to_pfn(sg_page((&sgl[i])));
 579
 580         } else if (scsi_sglist(scmnd)) {
 581                 request->data_buffer.offset =
 582                         virt_to_phys(scsi_sglist(scmnd)) & (PAGE_SIZE-1);
 583                 request->data_buffer.pfn_array[0] =
 584                         virt_to_phys(scsi_sglist(scmnd)) >> PAGE_SHIFT;
 585         }
 586
 587 retry_request:
 588         /* Invokes the vsc to start an IO */
 589         ret = storvsc_do_io(dev, &cmd_request->request);
 590
 591         if (ret == -EAGAIN) {
 592                 /* no more space */
 593
 594                 if (cmd_request->bounce_sgl_count) {
 595                         /*
 596                          * FIXME: We can optimize on writes by just skipping
 597                          * this
 598                          */
 599                         copy_from_bounce_buffer(scsi_sglist(scmnd),
 600                                                 cmd_request->bounce_sgl,
 601                                                 scsi_sg_count(scmnd));
 602                         destroy_bounce_buffer(cmd_request->bounce_sgl,
 603                                               cmd_request->bounce_sgl_count);
 604                 }
 605
 606                 kmem_cache_free(host_dev->request_pool, cmd_request);
 607
 608                 scmnd->scsi_done = NULL;
 609                 scmnd->host_scribble = NULL;
 610
 611                 ret = SCSI_MLQUEUE_DEVICE_BUSY;
 612         }
 613
 614         return ret;
 615 }
 616
 617 static DEF_SCSI_QCMD(storvsc_queuecommand)
 618
 619
 620 /* Scsi driver */
 621 static struct scsi_host_template scsi_driver = {
 622         .module =               THIS_MODULE,
 623         .name =                 "storvsc_host_t",
 624         .bios_param =           storvsc_get_chs,
 625         .queuecommand =         storvsc_queuecommand,
 626         .eh_host_reset_handler =        storvsc_host_reset_handler,
 627         .slave_alloc =          storvsc_device_alloc,
 628         .slave_configure =      storvsc_device_configure,
 629         .cmd_per_lun =          1,
 630         /* 64 max_queue * 1 target */
 631         .can_queue =            STORVSC_MAX_IO_REQUESTS*STORVSC_MAX_TARGETS,
 632         .this_id =              -1,
 633         /* no use setting to 0 since ll_blk_rw reset it to 1 */
 634         /* currently 32 */
 635         .sg_tablesize =         MAX_MULTIPAGE_BUFFER_COUNT,
 636         /*
 637          * ENABLE_CLUSTERING allows mutiple physically contig bio_vecs to merge
 638          * into 1 sg element. If set, we must limit the max_segment_size to
 639          * PAGE_SIZE, otherwise we may get 1 sg element that represents
 640          * multiple
 641          */
 642         /* physically contig pfns (ie sg[x].length > PAGE_SIZE). */
 643         .use_clustering =       ENABLE_CLUSTERING,
 644         /* Make sure we dont get a sg segment crosses a page boundary */
 645         .dma_boundary =         PAGE_SIZE-1,
 646 };
 647
 648 /*
 649  * The storvsc_probe function assumes that the IDE guid
 650  * is the second entry.
 651  */
 652 static const struct hv_vmbus_device_id id_table[] = {
 653         /* SCSI guid */
 654         { VMBUS_DEVICE(0xd9, 0x63, 0x61, 0xba, 0xa1, 0x04, 0x29, 0x4d,
 655                        0xb6, 0x05, 0x72, 0xe2, 0xff, 0xb1, 0xdc, 0x7f) },
 656         /* IDE guid */
 657         { VMBUS_DEVICE(0x32, 0x26, 0x41, 0x32, 0xcb, 0x86, 0xa2, 0x44,
 658                        0x9b, 0x5c, 0x50, 0xd1, 0x41, 0x73, 0x54, 0xf5) },
 659         { },
 660 };
 661
 662 MODULE_DEVICE_TABLE(vmbus, id_table);
 663
 664
 665 /*
 666  * storvsc_probe - Add a new device for this driver
 667  */
 668
 669 static int storvsc_probe(struct hv_device *device)
 670 {
 671         int ret;
 672         struct Scsi_Host *host;
 673         struct hv_host_device *host_dev;
 674         struct storvsc_device_info device_info;
 675         bool dev_is_ide;
 676         int path = 0;
 677         int target = 0;
 678
 679         if (!memcmp(&device->dev_type.b, id_table[1].guid, sizeof(uuid_le)))
 680                 dev_is_ide = true;
 681         else
 682                 dev_is_ide = false;
 683
 684         host = scsi_host_alloc(&scsi_driver,
 685                                sizeof(struct hv_host_device));
 686         if (!host)
 687                 return -ENOMEM;
 688
 689         dev_set_drvdata(&device->device, host);
 690
 691         host_dev = (struct hv_host_device *)host->hostdata;
 692         memset(host_dev, 0, sizeof(struct hv_host_device));
 693
 694         host_dev->port = host->host_no;
 695         host_dev->dev = device;
 696
 697         host_dev->request_pool =
 698                                 kmem_cache_create(dev_name(&device->device),
 699                                         sizeof(struct storvsc_cmd_request), 0,
 700                                         SLAB_HWCACHE_ALIGN, NULL);
 701
 702         if (!host_dev->request_pool) {
 703                 scsi_host_put(host);
 704                 return -ENOMEM;
 705         }
 706
 707         device_info.port_number = host->host_no;
 708         device_info.ring_buffer_size  = storvsc_ringbuffer_size;
 709         /* Call to the vsc driver to add the device */
 710         ret = storvsc_dev_add(device, (void *)&device_info);
 711
 712         if (ret != 0) {
 713                 kmem_cache_destroy(host_dev->request_pool);
 714                 scsi_host_put(host);
 715                 return -ENODEV;
 716         }
 717
 718         if (dev_is_ide)
 719                 storvsc_get_ide_info(device, &target, &path);
 720
 721         host_dev->path = device_info.path_id;
 722         host_dev->target = device_info.target_id;
 723
 724         /* max # of devices per target */
 725         host->max_lun = STORVSC_MAX_LUNS_PER_TARGET;
 726         /* max # of targets per channel */
 727         host->max_id = STORVSC_MAX_TARGETS;
 728         /* max # of channels */
 729         host->max_channel = STORVSC_MAX_CHANNELS - 1;
 730
 731         /* Register the HBA and start the scsi bus scan */
 732         ret = scsi_add_host(host, &device->device);
 733         if (ret != 0)
 734                 goto err_out;
 735
 736         if (!dev_is_ide) {
 737                 scsi_scan_host(host);
 738                 return 0;
 739         }
 740         ret = scsi_add_device(host, 0, target, 0);
 741         if (ret) {
 742                 scsi_remove_host(host);
 743                 goto err_out;
 744         }
 745         return 0;
 746
 747 err_out:
 748         storvsc_dev_remove(device);
 749         kmem_cache_destroy(host_dev->request_pool);
 750         scsi_host_put(host);
 751         return -ENODEV;
 752 }
 753
 754 /* The one and only one */
 755
 756 static struct hv_driver storvsc_drv = {
 757         .name = "storvsc",
 758         .id_table = id_table,
 759         .probe = storvsc_probe,
 760         .remove = storvsc_remove,
 761 };
 762
 763 static int __init storvsc_drv_init(void)
 764 {
 765         u32 max_outstanding_req_per_channel;
 766
 767         /*
 768          * Divide the ring buffer data size (which is 1 page less
 769          * than the ring buffer size since that page is reserved for
 770          * the ring buffer indices) by the max request size (which is
 771          * vmbus_channel_packet_multipage_buffer + struct vstor_packet + u64)
 772          */
 773         max_outstanding_req_per_channel =
 774                 ((storvsc_ringbuffer_size - PAGE_SIZE) /
 775                 ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
 776                 sizeof(struct vstor_packet) + sizeof(u64),
 777                 sizeof(u64)));
 778
 779         if (max_outstanding_req_per_channel <
 780             STORVSC_MAX_IO_REQUESTS)
 781                 return -EINVAL;
 782
 783         return vmbus_driver_register(&storvsc_drv);
 784 }
 785
 786 static void __exit storvsc_drv_exit(void)
 787 {
 788         vmbus_driver_unregister(&storvsc_drv);
 789 }
 790
 791 MODULE_LICENSE("GPL");
 792 MODULE_VERSION(HV_DRV_VERSION);
 793 MODULE_DESCRIPTION("Microsoft Hyper-V virtual storage driver");
 794 module_init(storvsc_drv_init);
 795 module_exit(storvsc_drv_exit);