err.no Git - linux-2.6/blob - drivers/scsi/device_handler/scsi_dh_rdac.c

   1 /*
   2  * Engenio/LSI RDAC SCSI Device Handler
   3  *
   4  * Copyright (C) 2005 Mike Christie. All rights reserved.
   5  * Copyright (C) Chandra Seetharaman, IBM Corp. 2007
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  20  *
  21  */
  22 #include <scsi/scsi.h>
  23 #include <scsi/scsi_eh.h>
  24 #include <scsi/scsi_dh.h>
  25
  26 #define RDAC_NAME "rdac"
  27
  28 /*
  29  * LSI mode page stuff
  30  *
  31  * These struct definitions and the forming of the
  32  * mode page were taken from the LSI RDAC 2.4 GPL'd
  33  * driver, and then converted to Linux conventions.
  34  */
  35 #define RDAC_QUIESCENCE_TIME 20;
  36 /*
  37  * Page Codes
  38  */
  39 #define RDAC_PAGE_CODE_REDUNDANT_CONTROLLER 0x2c
  40
  41 /*
  42  * Controller modes definitions
  43  */
  44 #define RDAC_MODE_TRANSFER_SPECIFIED_LUNS       0x02
  45
  46 /*
  47  * RDAC Options field
  48  */
  49 #define RDAC_FORCED_QUIESENCE 0x02
  50
  51 #define RDAC_TIMEOUT    (60 * HZ)
  52 #define RDAC_RETRIES    3
  53
  54 struct rdac_mode_6_hdr {
  55         u8      data_len;
  56         u8      medium_type;
  57         u8      device_params;
  58         u8      block_desc_len;
  59 };
  60
  61 struct rdac_mode_10_hdr {
  62         u16     data_len;
  63         u8      medium_type;
  64         u8      device_params;
  65         u16     reserved;
  66         u16     block_desc_len;
  67 };
  68
  69 struct rdac_mode_common {
  70         u8      controller_serial[16];
  71         u8      alt_controller_serial[16];
  72         u8      rdac_mode[2];
  73         u8      alt_rdac_mode[2];
  74         u8      quiescence_timeout;
  75         u8      rdac_options;
  76 };
  77
  78 struct rdac_pg_legacy {
  79         struct rdac_mode_6_hdr hdr;
  80         u8      page_code;
  81         u8      page_len;
  82         struct rdac_mode_common common;
  83 #define MODE6_MAX_LUN   32
  84         u8      lun_table[MODE6_MAX_LUN];
  85         u8      reserved2[32];
  86         u8      reserved3;
  87         u8      reserved4;
  88 };
  89
  90 struct rdac_pg_expanded {
  91         struct rdac_mode_10_hdr hdr;
  92         u8      page_code;
  93         u8      subpage_code;
  94         u8      page_len[2];
  95         struct rdac_mode_common common;
  96         u8      lun_table[256];
  97         u8      reserved3;
  98         u8      reserved4;
  99 };
 100
 101 struct c9_inquiry {
 102         u8      peripheral_info;
 103         u8      page_code;      /* 0xC9 */
 104         u8      reserved1;
 105         u8      page_len;
 106         u8      page_id[4];     /* "vace" */
 107         u8      avte_cvp;
 108         u8      path_prio;
 109         u8      reserved2[38];
 110 };
 111
 112 #define SUBSYS_ID_LEN   16
 113 #define SLOT_ID_LEN     2
 114
 115 struct c4_inquiry {
 116         u8      peripheral_info;
 117         u8      page_code;      /* 0xC4 */
 118         u8      reserved1;
 119         u8      page_len;
 120         u8      page_id[4];     /* "subs" */
 121         u8      subsys_id[SUBSYS_ID_LEN];
 122         u8      revision[4];
 123         u8      slot_id[SLOT_ID_LEN];
 124         u8      reserved[2];
 125 };
 126
 127 struct rdac_controller {
 128         u8                      subsys_id[SUBSYS_ID_LEN];
 129         u8                      slot_id[SLOT_ID_LEN];
 130         int                     use_ms10;
 131         struct kref             kref;
 132         struct list_head        node; /* list of all controllers */
 133         union                   {
 134                 struct rdac_pg_legacy legacy;
 135                 struct rdac_pg_expanded expanded;
 136         } mode_select;
 137 };
 138 struct c8_inquiry {
 139         u8      peripheral_info;
 140         u8      page_code; /* 0xC8 */
 141         u8      reserved1;
 142         u8      page_len;
 143         u8      page_id[4]; /* "edid" */
 144         u8      reserved2[3];
 145         u8      vol_uniq_id_len;
 146         u8      vol_uniq_id[16];
 147         u8      vol_user_label_len;
 148         u8      vol_user_label[60];
 149         u8      array_uniq_id_len;
 150         u8      array_unique_id[16];
 151         u8      array_user_label_len;
 152         u8      array_user_label[60];
 153         u8      lun[8];
 154 };
 155
 156 struct c2_inquiry {
 157         u8      peripheral_info;
 158         u8      page_code;      /* 0xC2 */
 159         u8      reserved1;
 160         u8      page_len;
 161         u8      page_id[4];     /* "swr4" */
 162         u8      sw_version[3];
 163         u8      sw_date[3];
 164         u8      features_enabled;
 165         u8      max_lun_supported;
 166         u8      partitions[239]; /* Total allocation length should be 0xFF */
 167 };
 168
 169 struct rdac_dh_data {
 170         struct rdac_controller  *ctlr;
 171 #define UNINITIALIZED_LUN       (1 << 8)
 172         unsigned                lun;
 173 #define RDAC_STATE_ACTIVE       0
 174 #define RDAC_STATE_PASSIVE      1
 175         unsigned char           state;
 176         unsigned char           sense[SCSI_SENSE_BUFFERSIZE];
 177         union                   {
 178                 struct c2_inquiry c2;
 179                 struct c4_inquiry c4;
 180                 struct c8_inquiry c8;
 181                 struct c9_inquiry c9;
 182         } inq;
 183 };
 184
 185 static LIST_HEAD(ctlr_list);
 186 static DEFINE_SPINLOCK(list_lock);
 187
 188 static inline struct rdac_dh_data *get_rdac_data(struct scsi_device *sdev)
 189 {
 190         struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
 191         BUG_ON(scsi_dh_data == NULL);
 192         return ((struct rdac_dh_data *) scsi_dh_data->buf);
 193 }
 194
 195 static struct request *get_rdac_req(struct scsi_device *sdev,
 196                         void *buffer, unsigned buflen, int rw)
 197 {
 198         struct request *rq;
 199         struct request_queue *q = sdev->request_queue;
 200         struct rdac_dh_data *h = get_rdac_data(sdev);
 201
 202         rq = blk_get_request(q, rw, GFP_KERNEL);
 203
 204         if (!rq) {
 205                 sdev_printk(KERN_INFO, sdev,
 206                                 "get_rdac_req: blk_get_request failed.\n");
 207                 return NULL;
 208         }
 209
 210         if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_KERNEL)) {
 211                 blk_put_request(rq);
 212                 sdev_printk(KERN_INFO, sdev,
 213                                 "get_rdac_req: blk_rq_map_kern failed.\n");
 214                 return NULL;
 215         }
 216
 217         memset(&rq->cmd, 0, BLK_MAX_CDB);
 218         rq->sense = h->sense;
 219         memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
 220         rq->sense_len = 0;
 221
 222         rq->cmd_type = REQ_TYPE_BLOCK_PC;
 223         rq->cmd_flags |= REQ_FAILFAST | REQ_NOMERGE;
 224         rq->retries = RDAC_RETRIES;
 225         rq->timeout = RDAC_TIMEOUT;
 226
 227         return rq;
 228 }
 229
 230 static struct request *rdac_failover_get(struct scsi_device *sdev)
 231 {
 232         struct request *rq;
 233         struct rdac_mode_common *common;
 234         unsigned data_size;
 235         struct rdac_dh_data *h = get_rdac_data(sdev);
 236
 237         if (h->ctlr->use_ms10) {
 238                 struct rdac_pg_expanded *rdac_pg;
 239
 240                 data_size = sizeof(struct rdac_pg_expanded);
 241                 rdac_pg = &h->ctlr->mode_select.expanded;
 242                 memset(rdac_pg, 0, data_size);
 243                 common = &rdac_pg->common;
 244                 rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER + 0x40;
 245                 rdac_pg->subpage_code = 0x1;
 246                 rdac_pg->page_len[0] = 0x01;
 247                 rdac_pg->page_len[1] = 0x28;
 248                 rdac_pg->lun_table[h->lun] = 0x81;
 249         } else {
 250                 struct rdac_pg_legacy *rdac_pg;
 251
 252                 data_size = sizeof(struct rdac_pg_legacy);
 253                 rdac_pg = &h->ctlr->mode_select.legacy;
 254                 memset(rdac_pg, 0, data_size);
 255                 common = &rdac_pg->common;
 256                 rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER;
 257                 rdac_pg->page_len = 0x68;
 258                 rdac_pg->lun_table[h->lun] = 0x81;
 259         }
 260         common->rdac_mode[1] = RDAC_MODE_TRANSFER_SPECIFIED_LUNS;
 261         common->quiescence_timeout = RDAC_QUIESCENCE_TIME;
 262         common->rdac_options = RDAC_FORCED_QUIESENCE;
 263
 264         /* get request for block layer packet command */
 265         rq = get_rdac_req(sdev, &h->ctlr->mode_select, data_size, WRITE);
 266         if (!rq)
 267                 return NULL;
 268
 269         /* Prepare the command. */
 270         if (h->ctlr->use_ms10) {
 271                 rq->cmd[0] = MODE_SELECT_10;
 272                 rq->cmd[7] = data_size >> 8;
 273                 rq->cmd[8] = data_size & 0xff;
 274         } else {
 275                 rq->cmd[0] = MODE_SELECT;
 276                 rq->cmd[4] = data_size;
 277         }
 278         rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
 279
 280         return rq;
 281 }
 282
 283 static void release_controller(struct kref *kref)
 284 {
 285         struct rdac_controller *ctlr;
 286         ctlr = container_of(kref, struct rdac_controller, kref);
 287
 288         spin_lock(&list_lock);
 289         list_del(&ctlr->node);
 290         spin_unlock(&list_lock);
 291         kfree(ctlr);
 292 }
 293
 294 static struct rdac_controller *get_controller(u8 *subsys_id, u8 *slot_id)
 295 {
 296         struct rdac_controller *ctlr, *tmp;
 297
 298         spin_lock(&list_lock);
 299
 300         list_for_each_entry(tmp, &ctlr_list, node) {
 301                 if ((memcmp(tmp->subsys_id, subsys_id, SUBSYS_ID_LEN) == 0) &&
 302                           (memcmp(tmp->slot_id, slot_id, SLOT_ID_LEN) == 0)) {
 303                         kref_get(&tmp->kref);
 304                         spin_unlock(&list_lock);
 305                         return tmp;
 306                 }
 307         }
 308         ctlr = kmalloc(sizeof(*ctlr), GFP_ATOMIC);
 309         if (!ctlr)
 310                 goto done;
 311
 312         /* initialize fields of controller */
 313         memcpy(ctlr->subsys_id, subsys_id, SUBSYS_ID_LEN);
 314         memcpy(ctlr->slot_id, slot_id, SLOT_ID_LEN);
 315         kref_init(&ctlr->kref);
 316         ctlr->use_ms10 = -1;
 317         list_add(&ctlr->node, &ctlr_list);
 318 done:
 319         spin_unlock(&list_lock);
 320         return ctlr;
 321 }
 322
 323 static int submit_inquiry(struct scsi_device *sdev, int page_code,
 324                 unsigned int len)
 325 {
 326         struct request *rq;
 327         struct request_queue *q = sdev->request_queue;
 328         struct rdac_dh_data *h = get_rdac_data(sdev);
 329         int err = SCSI_DH_RES_TEMP_UNAVAIL;
 330
 331         rq = get_rdac_req(sdev, &h->inq, len, READ);
 332         if (!rq)
 333                 goto done;
 334
 335         /* Prepare the command. */
 336         rq->cmd[0] = INQUIRY;
 337         rq->cmd[1] = 1;
 338         rq->cmd[2] = page_code;
 339         rq->cmd[4] = len;
 340         rq->cmd_len = COMMAND_SIZE(INQUIRY);
 341         err = blk_execute_rq(q, NULL, rq, 1);
 342         if (err == -EIO)
 343                 err = SCSI_DH_IO;
 344 done:
 345         return err;
 346 }
 347
 348 static int get_lun(struct scsi_device *sdev)
 349 {
 350         int err;
 351         struct c8_inquiry *inqp;
 352         struct rdac_dh_data *h = get_rdac_data(sdev);
 353
 354         err = submit_inquiry(sdev, 0xC8, sizeof(struct c8_inquiry));
 355         if (err == SCSI_DH_OK) {
 356                 inqp = &h->inq.c8;
 357                 h->lun = inqp->lun[7]; /* currently it uses only one byte */
 358         }
 359         return err;
 360 }
 361
 362 #define RDAC_OWNED      0
 363 #define RDAC_UNOWNED    1
 364 #define RDAC_FAILED     2
 365 static int check_ownership(struct scsi_device *sdev)
 366 {
 367         int err;
 368         struct c9_inquiry *inqp;
 369         struct rdac_dh_data *h = get_rdac_data(sdev);
 370
 371         err = submit_inquiry(sdev, 0xC9, sizeof(struct c9_inquiry));
 372         if (err == SCSI_DH_OK) {
 373                 err = RDAC_UNOWNED;
 374                 inqp = &h->inq.c9;
 375                 /*
 376                  * If in AVT mode or if the path already owns the LUN,
 377                  * return RDAC_OWNED;
 378                  */
 379                 if (((inqp->avte_cvp >> 7) == 0x1) ||
 380                                  ((inqp->avte_cvp & 0x1) != 0))
 381                         err = RDAC_OWNED;
 382         } else
 383                 err = RDAC_FAILED;
 384         return err;
 385 }
 386
 387 static int initialize_controller(struct scsi_device *sdev)
 388 {
 389         int err;
 390         struct c4_inquiry *inqp;
 391         struct rdac_dh_data *h = get_rdac_data(sdev);
 392
 393         err = submit_inquiry(sdev, 0xC4, sizeof(struct c4_inquiry));
 394         if (err == SCSI_DH_OK) {
 395                 inqp = &h->inq.c4;
 396                 h->ctlr = get_controller(inqp->subsys_id, inqp->slot_id);
 397                 if (!h->ctlr)
 398                         err = SCSI_DH_RES_TEMP_UNAVAIL;
 399         }
 400         return err;
 401 }
 402
 403 static int set_mode_select(struct scsi_device *sdev)
 404 {
 405         int err;
 406         struct c2_inquiry *inqp;
 407         struct rdac_dh_data *h = get_rdac_data(sdev);
 408
 409         err = submit_inquiry(sdev, 0xC2, sizeof(struct c2_inquiry));
 410         if (err == SCSI_DH_OK) {
 411                 inqp = &h->inq.c2;
 412                 /*
 413                  * If more than MODE6_MAX_LUN luns are supported, use
 414                  * mode select 10
 415                  */
 416                 if (inqp->max_lun_supported >= MODE6_MAX_LUN)
 417                         h->ctlr->use_ms10 = 1;
 418                 else
 419                         h->ctlr->use_ms10 = 0;
 420         }
 421         return err;
 422 }
 423
 424 static int mode_select_handle_sense(struct scsi_device *sdev)
 425 {
 426         struct scsi_sense_hdr sense_hdr;
 427         struct rdac_dh_data *h = get_rdac_data(sdev);
 428         int sense, err = SCSI_DH_IO, ret;
 429
 430         ret = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE, &sense_hdr);
 431         if (!ret)
 432                 goto done;
 433
 434         err = SCSI_DH_OK;
 435         sense = (sense_hdr.sense_key << 16) | (sense_hdr.asc << 8) |
 436                         sense_hdr.ascq;
 437         /* If it is retryable failure, submit the c9 inquiry again */
 438         if (sense == 0x59136 || sense == 0x68b02 || sense == 0xb8b02 ||
 439                             sense == 0x62900) {
 440                 /* 0x59136    - Command lock contention
 441                  * 0x[6b]8b02 - Quiesense in progress or achieved
 442                  * 0x62900    - Power On, Reset, or Bus Device Reset
 443                  */
 444                 err = SCSI_DH_RETRY;
 445         }
 446
 447         if (sense)
 448                 sdev_printk(KERN_INFO, sdev,
 449                         "MODE_SELECT failed with sense 0x%x.\n", sense);
 450 done:
 451         return err;
 452 }
 453
 454 static int send_mode_select(struct scsi_device *sdev)
 455 {
 456         struct request *rq;
 457         struct request_queue *q = sdev->request_queue;
 458         struct rdac_dh_data *h = get_rdac_data(sdev);
 459         int err = SCSI_DH_RES_TEMP_UNAVAIL;
 460
 461         rq = rdac_failover_get(sdev);
 462         if (!rq)
 463                 goto done;
 464
 465         sdev_printk(KERN_INFO, sdev, "queueing MODE_SELECT command.\n");
 466
 467         err = blk_execute_rq(q, NULL, rq, 1);
 468         if (err != SCSI_DH_OK)
 469                 err = mode_select_handle_sense(sdev);
 470         if (err == SCSI_DH_OK)
 471                 h->state = RDAC_STATE_ACTIVE;
 472 done:
 473         return err;
 474 }
 475
 476 static int rdac_activate(struct scsi_device *sdev)
 477 {
 478         struct rdac_dh_data *h = get_rdac_data(sdev);
 479         int err = SCSI_DH_OK;
 480
 481         if (h->lun == UNINITIALIZED_LUN) {
 482                 err = get_lun(sdev);
 483                 if (err != SCSI_DH_OK)
 484                         goto done;
 485         }
 486
 487         err = check_ownership(sdev);
 488         switch (err) {
 489         case RDAC_UNOWNED:
 490                 break;
 491         case RDAC_OWNED:
 492                 err = SCSI_DH_OK;
 493                 goto done;
 494         case RDAC_FAILED:
 495         default:
 496                 err = SCSI_DH_IO;
 497                 goto done;
 498         }
 499
 500         if (!h->ctlr) {
 501                 err = initialize_controller(sdev);
 502                 if (err != SCSI_DH_OK)
 503                         goto done;
 504         }
 505
 506         if (h->ctlr->use_ms10 == -1) {
 507                 err = set_mode_select(sdev);
 508                 if (err != SCSI_DH_OK)
 509                         goto done;
 510         }
 511
 512         err = send_mode_select(sdev);
 513 done:
 514         return err;
 515 }
 516
 517 static int rdac_prep_fn(struct scsi_device *sdev, struct request *req)
 518 {
 519         struct rdac_dh_data *h = get_rdac_data(sdev);
 520         int ret = BLKPREP_OK;
 521
 522         if (h->state != RDAC_STATE_ACTIVE) {
 523                 ret = BLKPREP_KILL;
 524                 req->cmd_flags |= REQ_QUIET;
 525         }
 526         return ret;
 527
 528 }
 529
 530 static int rdac_check_sense(struct scsi_device *sdev,
 531                                 struct scsi_sense_hdr *sense_hdr)
 532 {
 533         struct rdac_dh_data *h = get_rdac_data(sdev);
 534         switch (sense_hdr->sense_key) {
 535         case NOT_READY:
 536                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x81)
 537                         /* LUN Not Ready - Storage firmware incompatible
 538                          * Manual code synchonisation required.
 539                          *
 540                          * Nothing we can do here. Try to bypass the path.
 541                          */
 542                         return SUCCESS;
 543                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0xA1)
 544                         /* LUN Not Ready - Quiescense in progress
 545                          *
 546                          * Just retry and wait.
 547                          */
 548                         return NEEDS_RETRY;
 549                 break;
 550         case ILLEGAL_REQUEST:
 551                 if (sense_hdr->asc == 0x94 && sense_hdr->ascq == 0x01) {
 552                         /* Invalid Request - Current Logical Unit Ownership.
 553                          * Controller is not the current owner of the LUN,
 554                          * Fail the path, so that the other path be used.
 555                          */
 556                         h->state = RDAC_STATE_PASSIVE;
 557                         return SUCCESS;
 558                 }
 559                 break;
 560         case UNIT_ATTENTION:
 561                 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
 562                         /*
 563                          * Power On, Reset, or Bus Device Reset, just retry.
 564                          */
 565                         return NEEDS_RETRY;
 566                 break;
 567         }
 568         /* success just means we do not care what scsi-ml does */
 569         return SCSI_RETURN_NOT_HANDLED;
 570 }
 571
 572 static const struct {
 573         char *vendor;
 574         char *model;
 575 } rdac_dev_list[] = {
 576         {"IBM", "1722"},
 577         {"IBM", "1724"},
 578         {"IBM", "1726"},
 579         {"IBM", "1742"},
 580         {"IBM", "1814"},
 581         {"IBM", "1815"},
 582         {"IBM", "1818"},
 583         {"IBM", "3526"},
 584         {"SGI", "TP9400"},
 585         {"SGI", "TP9500"},
 586         {"SGI", "IS"},
 587         {"STK", "OPENstorage D280"},
 588         {"SUN", "CSM200_R"},
 589         {"SUN", "LCSM100_F"},
 590         {NULL, NULL},
 591 };
 592
 593 static int rdac_bus_notify(struct notifier_block *, unsigned long, void *);
 594
 595 static struct scsi_device_handler rdac_dh = {
 596         .name = RDAC_NAME,
 597         .module = THIS_MODULE,
 598         .nb.notifier_call = rdac_bus_notify,
 599         .prep_fn = rdac_prep_fn,
 600         .check_sense = rdac_check_sense,
 601         .activate = rdac_activate,
 602 };
 603
 604 /*
 605  * TODO: need some interface so we can set trespass values
 606  */
 607 static int rdac_bus_notify(struct notifier_block *nb,
 608                             unsigned long action, void *data)
 609 {
 610         struct device *dev = data;
 611         struct scsi_device *sdev = to_scsi_device(dev);
 612         struct scsi_dh_data *scsi_dh_data;
 613         struct rdac_dh_data *h;
 614         int i, found = 0;
 615         unsigned long flags;
 616
 617         if (action == BUS_NOTIFY_ADD_DEVICE) {
 618                 for (i = 0; rdac_dev_list[i].vendor; i++) {
 619                         if (!strncmp(sdev->vendor, rdac_dev_list[i].vendor,
 620                                      strlen(rdac_dev_list[i].vendor)) &&
 621                             !strncmp(sdev->model, rdac_dev_list[i].model,
 622                                      strlen(rdac_dev_list[i].model))) {
 623                                 found = 1;
 624                                 break;
 625                         }
 626                 }
 627                 if (!found)
 628                         goto out;
 629
 630                 scsi_dh_data = kzalloc(sizeof(struct scsi_device_handler *)
 631                                 + sizeof(*h) , GFP_KERNEL);
 632                 if (!scsi_dh_data) {
 633                         sdev_printk(KERN_ERR, sdev, "Attach failed %s.\n",
 634                                     RDAC_NAME);
 635                         goto out;
 636                 }
 637
 638                 scsi_dh_data->scsi_dh = &rdac_dh;
 639                 h = (struct rdac_dh_data *) scsi_dh_data->buf;
 640                 h->lun = UNINITIALIZED_LUN;
 641                 h->state = RDAC_STATE_ACTIVE;
 642                 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
 643                 sdev->scsi_dh_data = scsi_dh_data;
 644                 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
 645                 try_module_get(THIS_MODULE);
 646
 647                 sdev_printk(KERN_NOTICE, sdev, "Attached %s.\n", RDAC_NAME);
 648
 649         } else if (action == BUS_NOTIFY_DEL_DEVICE) {
 650                 if (sdev->scsi_dh_data == NULL ||
 651                                 sdev->scsi_dh_data->scsi_dh != &rdac_dh)
 652                         goto out;
 653
 654                 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
 655                 scsi_dh_data = sdev->scsi_dh_data;
 656                 sdev->scsi_dh_data = NULL;
 657                 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
 658
 659                 h = (struct rdac_dh_data *) scsi_dh_data->buf;
 660                 if (h->ctlr)
 661                         kref_put(&h->ctlr->kref, release_controller);
 662                 kfree(scsi_dh_data);
 663                 module_put(THIS_MODULE);
 664                 sdev_printk(KERN_NOTICE, sdev, "Dettached %s.\n", RDAC_NAME);
 665         }
 666
 667 out:
 668         return 0;
 669 }
 670
 671 static int __init rdac_init(void)
 672 {
 673         int r;
 674
 675         r = scsi_register_device_handler(&rdac_dh);
 676         if (r != 0)
 677                 printk(KERN_ERR "Failed to register scsi device handler.");
 678         return r;
 679 }
 680
 681 static void __exit rdac_exit(void)
 682 {
 683         scsi_unregister_device_handler(&rdac_dh);
 684 }
 685
 686 module_init(rdac_init);
 687 module_exit(rdac_exit);
 688
 689 MODULE_DESCRIPTION("Multipath LSI/Engenio RDAC driver");
 690 MODULE_AUTHOR("Mike Christie, Chandra Seetharaman");
 691 MODULE_LICENSE("GPL");