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