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
 177 #define RDAC_LUN_UNOWNED        0
 178 #define RDAC_LUN_OWNED          1
 179 #define RDAC_LUN_AVT            2
 180         char                    lun_state;
 181         unsigned char           sense[SCSI_SENSE_BUFFERSIZE];
 182         union                   {
 183                 struct c2_inquiry c2;
 184                 struct c4_inquiry c4;
 185                 struct c8_inquiry c8;
 186                 struct c9_inquiry c9;
 187         } inq;
 188 };
 189
 190 static const char *lun_state[] =
 191 {
 192         "unowned",
 193         "owned",
 194         "owned (AVT mode)",
 195 };
 196
 197 static LIST_HEAD(ctlr_list);
 198 static DEFINE_SPINLOCK(list_lock);
 199
 200 static inline struct rdac_dh_data *get_rdac_data(struct scsi_device *sdev)
 201 {
 202         struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
 203         BUG_ON(scsi_dh_data == NULL);
 204         return ((struct rdac_dh_data *) scsi_dh_data->buf);
 205 }
 206
 207 static struct request *get_rdac_req(struct scsi_device *sdev,
 208                         void *buffer, unsigned buflen, int rw)
 209 {
 210         struct request *rq;
 211         struct request_queue *q = sdev->request_queue;
 212
 213         rq = blk_get_request(q, rw, GFP_NOIO);
 214
 215         if (!rq) {
 216                 sdev_printk(KERN_INFO, sdev,
 217                                 "get_rdac_req: blk_get_request failed.\n");
 218                 return NULL;
 219         }
 220
 221         if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_NOIO)) {
 222                 blk_put_request(rq);
 223                 sdev_printk(KERN_INFO, sdev,
 224                                 "get_rdac_req: blk_rq_map_kern failed.\n");
 225                 return NULL;
 226         }
 227
 228         rq->cmd_type = REQ_TYPE_BLOCK_PC;
 229         rq->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
 230                          REQ_FAILFAST_DRIVER;
 231         rq->retries = RDAC_RETRIES;
 232         rq->timeout = RDAC_TIMEOUT;
 233
 234         return rq;
 235 }
 236
 237 static struct request *rdac_failover_get(struct scsi_device *sdev,
 238                                          struct rdac_dh_data *h)
 239 {
 240         struct request *rq;
 241         struct rdac_mode_common *common;
 242         unsigned data_size;
 243
 244         if (h->ctlr->use_ms10) {
 245                 struct rdac_pg_expanded *rdac_pg;
 246
 247                 data_size = sizeof(struct rdac_pg_expanded);
 248                 rdac_pg = &h->ctlr->mode_select.expanded;
 249                 memset(rdac_pg, 0, data_size);
 250                 common = &rdac_pg->common;
 251                 rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER + 0x40;
 252                 rdac_pg->subpage_code = 0x1;
 253                 rdac_pg->page_len[0] = 0x01;
 254                 rdac_pg->page_len[1] = 0x28;
 255                 rdac_pg->lun_table[h->lun] = 0x81;
 256         } else {
 257                 struct rdac_pg_legacy *rdac_pg;
 258
 259                 data_size = sizeof(struct rdac_pg_legacy);
 260                 rdac_pg = &h->ctlr->mode_select.legacy;
 261                 memset(rdac_pg, 0, data_size);
 262                 common = &rdac_pg->common;
 263                 rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER;
 264                 rdac_pg->page_len = 0x68;
 265                 rdac_pg->lun_table[h->lun] = 0x81;
 266         }
 267         common->rdac_mode[1] = RDAC_MODE_TRANSFER_SPECIFIED_LUNS;
 268         common->quiescence_timeout = RDAC_QUIESCENCE_TIME;
 269         common->rdac_options = RDAC_FORCED_QUIESENCE;
 270
 271         /* get request for block layer packet command */
 272         rq = get_rdac_req(sdev, &h->ctlr->mode_select, data_size, WRITE);
 273         if (!rq)
 274                 return NULL;
 275
 276         /* Prepare the command. */
 277         if (h->ctlr->use_ms10) {
 278                 rq->cmd[0] = MODE_SELECT_10;
 279                 rq->cmd[7] = data_size >> 8;
 280                 rq->cmd[8] = data_size & 0xff;
 281         } else {
 282                 rq->cmd[0] = MODE_SELECT;
 283                 rq->cmd[4] = data_size;
 284         }
 285         rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
 286
 287         rq->sense = h->sense;
 288         memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
 289         rq->sense_len = 0;
 290
 291         return rq;
 292 }
 293
 294 static void release_controller(struct kref *kref)
 295 {
 296         struct rdac_controller *ctlr;
 297         ctlr = container_of(kref, struct rdac_controller, kref);
 298
 299         spin_lock(&list_lock);
 300         list_del(&ctlr->node);
 301         spin_unlock(&list_lock);
 302         kfree(ctlr);
 303 }
 304
 305 static struct rdac_controller *get_controller(u8 *subsys_id, u8 *slot_id)
 306 {
 307         struct rdac_controller *ctlr, *tmp;
 308
 309         spin_lock(&list_lock);
 310
 311         list_for_each_entry(tmp, &ctlr_list, node) {
 312                 if ((memcmp(tmp->subsys_id, subsys_id, SUBSYS_ID_LEN) == 0) &&
 313                           (memcmp(tmp->slot_id, slot_id, SLOT_ID_LEN) == 0)) {
 314                         kref_get(&tmp->kref);
 315                         spin_unlock(&list_lock);
 316                         return tmp;
 317                 }
 318         }
 319         ctlr = kmalloc(sizeof(*ctlr), GFP_ATOMIC);
 320         if (!ctlr)
 321                 goto done;
 322
 323         /* initialize fields of controller */
 324         memcpy(ctlr->subsys_id, subsys_id, SUBSYS_ID_LEN);
 325         memcpy(ctlr->slot_id, slot_id, SLOT_ID_LEN);
 326         kref_init(&ctlr->kref);
 327         ctlr->use_ms10 = -1;
 328         list_add(&ctlr->node, &ctlr_list);
 329 done:
 330         spin_unlock(&list_lock);
 331         return ctlr;
 332 }
 333
 334 static int submit_inquiry(struct scsi_device *sdev, int page_code,
 335                           unsigned int len, struct rdac_dh_data *h)
 336 {
 337         struct request *rq;
 338         struct request_queue *q = sdev->request_queue;
 339         int err = SCSI_DH_RES_TEMP_UNAVAIL;
 340
 341         rq = get_rdac_req(sdev, &h->inq, len, READ);
 342         if (!rq)
 343                 goto done;
 344
 345         /* Prepare the command. */
 346         rq->cmd[0] = INQUIRY;
 347         rq->cmd[1] = 1;
 348         rq->cmd[2] = page_code;
 349         rq->cmd[4] = len;
 350         rq->cmd_len = COMMAND_SIZE(INQUIRY);
 351
 352         rq->sense = h->sense;
 353         memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
 354         rq->sense_len = 0;
 355
 356         err = blk_execute_rq(q, NULL, rq, 1);
 357         if (err == -EIO)
 358                 err = SCSI_DH_IO;
 359
 360         blk_put_request(rq);
 361 done:
 362         return err;
 363 }
 364
 365 static int get_lun(struct scsi_device *sdev, struct rdac_dh_data *h)
 366 {
 367         int err;
 368         struct c8_inquiry *inqp;
 369
 370         err = submit_inquiry(sdev, 0xC8, sizeof(struct c8_inquiry), h);
 371         if (err == SCSI_DH_OK) {
 372                 inqp = &h->inq.c8;
 373                 if (inqp->page_code != 0xc8)
 374                         return SCSI_DH_NOSYS;
 375                 if (inqp->page_id[0] != 'e' || inqp->page_id[1] != 'd' ||
 376                     inqp->page_id[2] != 'i' || inqp->page_id[3] != 'd')
 377                         return SCSI_DH_NOSYS;
 378                 h->lun = inqp->lun[7]; /* Uses only the last byte */
 379         }
 380         return err;
 381 }
 382
 383 static int check_ownership(struct scsi_device *sdev, struct rdac_dh_data *h)
 384 {
 385         int err;
 386         struct c9_inquiry *inqp;
 387
 388         h->lun_state = RDAC_LUN_UNOWNED;
 389         err = submit_inquiry(sdev, 0xC9, sizeof(struct c9_inquiry), h);
 390         if (err == SCSI_DH_OK) {
 391                 inqp = &h->inq.c9;
 392                 if ((inqp->avte_cvp >> 7) == 0x1) {
 393                         /* LUN in AVT mode */
 394                         sdev_printk(KERN_NOTICE, sdev,
 395                                     "%s: AVT mode detected\n",
 396                                     RDAC_NAME);
 397                         h->lun_state = RDAC_LUN_AVT;
 398                 } else if ((inqp->avte_cvp & 0x1) != 0) {
 399                         /* LUN was owned by the controller */
 400                         h->lun_state = RDAC_LUN_OWNED;
 401                 }
 402         }
 403
 404         if (h->lun_state == RDAC_LUN_UNOWNED)
 405                 h->state = RDAC_STATE_PASSIVE;
 406
 407         return err;
 408 }
 409
 410 static int initialize_controller(struct scsi_device *sdev,
 411                                  struct rdac_dh_data *h)
 412 {
 413         int err;
 414         struct c4_inquiry *inqp;
 415
 416         err = submit_inquiry(sdev, 0xC4, sizeof(struct c4_inquiry), h);
 417         if (err == SCSI_DH_OK) {
 418                 inqp = &h->inq.c4;
 419                 h->ctlr = get_controller(inqp->subsys_id, inqp->slot_id);
 420                 if (!h->ctlr)
 421                         err = SCSI_DH_RES_TEMP_UNAVAIL;
 422         }
 423         return err;
 424 }
 425
 426 static int set_mode_select(struct scsi_device *sdev, struct rdac_dh_data *h)
 427 {
 428         int err;
 429         struct c2_inquiry *inqp;
 430
 431         err = submit_inquiry(sdev, 0xC2, sizeof(struct c2_inquiry), h);
 432         if (err == SCSI_DH_OK) {
 433                 inqp = &h->inq.c2;
 434                 /*
 435                  * If more than MODE6_MAX_LUN luns are supported, use
 436                  * mode select 10
 437                  */
 438                 if (inqp->max_lun_supported >= MODE6_MAX_LUN)
 439                         h->ctlr->use_ms10 = 1;
 440                 else
 441                         h->ctlr->use_ms10 = 0;
 442         }
 443         return err;
 444 }
 445
 446 static int mode_select_handle_sense(struct scsi_device *sdev,
 447                                     unsigned char *sensebuf)
 448 {
 449         struct scsi_sense_hdr sense_hdr;
 450         int sense, err = SCSI_DH_IO, ret;
 451
 452         ret = scsi_normalize_sense(sensebuf, SCSI_SENSE_BUFFERSIZE, &sense_hdr);
 453         if (!ret)
 454                 goto done;
 455
 456         err = SCSI_DH_OK;
 457         sense = (sense_hdr.sense_key << 16) | (sense_hdr.asc << 8) |
 458                         sense_hdr.ascq;
 459         /* If it is retryable failure, submit the c9 inquiry again */
 460         if (sense == 0x59136 || sense == 0x68b02 || sense == 0xb8b02 ||
 461                             sense == 0x62900) {
 462                 /* 0x59136    - Command lock contention
 463                  * 0x[6b]8b02 - Quiesense in progress or achieved
 464                  * 0x62900    - Power On, Reset, or Bus Device Reset
 465                  */
 466                 err = SCSI_DH_RETRY;
 467         }
 468
 469         if (sense)
 470                 sdev_printk(KERN_INFO, sdev,
 471                         "MODE_SELECT failed with sense 0x%x.\n", sense);
 472 done:
 473         return err;
 474 }
 475
 476 static int send_mode_select(struct scsi_device *sdev, struct rdac_dh_data *h)
 477 {
 478         struct request *rq;
 479         struct request_queue *q = sdev->request_queue;
 480         int err = SCSI_DH_RES_TEMP_UNAVAIL;
 481
 482         rq = rdac_failover_get(sdev, h);
 483         if (!rq)
 484                 goto done;
 485
 486         sdev_printk(KERN_INFO, sdev, "queueing MODE_SELECT command.\n");
 487
 488         err = blk_execute_rq(q, NULL, rq, 1);
 489         if (err != SCSI_DH_OK)
 490                 err = mode_select_handle_sense(sdev, h->sense);
 491         if (err == SCSI_DH_OK)
 492                 h->state = RDAC_STATE_ACTIVE;
 493
 494         blk_put_request(rq);
 495 done:
 496         return err;
 497 }
 498
 499 static int rdac_activate(struct scsi_device *sdev)
 500 {
 501         struct rdac_dh_data *h = get_rdac_data(sdev);
 502         int err = SCSI_DH_OK;
 503
 504         err = check_ownership(sdev, h);
 505         if (err != SCSI_DH_OK)
 506                 goto done;
 507
 508         if (!h->ctlr) {
 509                 err = initialize_controller(sdev, h);
 510                 if (err != SCSI_DH_OK)
 511                         goto done;
 512         }
 513
 514         if (h->ctlr->use_ms10 == -1) {
 515                 err = set_mode_select(sdev, h);
 516                 if (err != SCSI_DH_OK)
 517                         goto done;
 518         }
 519         if (h->lun_state == RDAC_LUN_UNOWNED)
 520                 err = send_mode_select(sdev, h);
 521 done:
 522         return err;
 523 }
 524
 525 static int rdac_prep_fn(struct scsi_device *sdev, struct request *req)
 526 {
 527         struct rdac_dh_data *h = get_rdac_data(sdev);
 528         int ret = BLKPREP_OK;
 529
 530         if (h->state != RDAC_STATE_ACTIVE) {
 531                 ret = BLKPREP_KILL;
 532                 req->cmd_flags |= REQ_QUIET;
 533         }
 534         return ret;
 535
 536 }
 537
 538 static int rdac_check_sense(struct scsi_device *sdev,
 539                                 struct scsi_sense_hdr *sense_hdr)
 540 {
 541         struct rdac_dh_data *h = get_rdac_data(sdev);
 542         switch (sense_hdr->sense_key) {
 543         case NOT_READY:
 544                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x81)
 545                         /* LUN Not Ready - Storage firmware incompatible
 546                          * Manual code synchonisation required.
 547                          *
 548                          * Nothing we can do here. Try to bypass the path.
 549                          */
 550                         return SUCCESS;
 551                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0xA1)
 552                         /* LUN Not Ready - Quiescense in progress
 553                          *
 554                          * Just retry and wait.
 555                          */
 556                         return ADD_TO_MLQUEUE;
 557                 break;
 558         case ILLEGAL_REQUEST:
 559                 if (sense_hdr->asc == 0x94 && sense_hdr->ascq == 0x01) {
 560                         /* Invalid Request - Current Logical Unit Ownership.
 561                          * Controller is not the current owner of the LUN,
 562                          * Fail the path, so that the other path be used.
 563                          */
 564                         h->state = RDAC_STATE_PASSIVE;
 565                         return SUCCESS;
 566                 }
 567                 break;
 568         case UNIT_ATTENTION:
 569                 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
 570                         /*
 571                          * Power On, Reset, or Bus Device Reset, just retry.
 572                          */
 573                         return ADD_TO_MLQUEUE;
 574                 break;
 575         }
 576         /* success just means we do not care what scsi-ml does */
 577         return SCSI_RETURN_NOT_HANDLED;
 578 }
 579
 580 static const struct scsi_dh_devlist rdac_dev_list[] = {
 581         {"IBM", "1722"},
 582         {"IBM", "1724"},
 583         {"IBM", "1726"},
 584         {"IBM", "1742"},
 585         {"IBM", "1814"},
 586         {"IBM", "1815"},
 587         {"IBM", "1818"},
 588         {"IBM", "3526"},
 589         {"SGI", "TP9400"},
 590         {"SGI", "TP9500"},
 591         {"SGI", "IS"},
 592         {"STK", "OPENstorage D280"},
 593         {"SUN", "CSM200_R"},
 594         {"SUN", "LCSM100_F"},
 595         {"DELL", "MD3000"},
 596         {"DELL", "MD3000i"},
 597         {NULL, NULL},
 598 };
 599
 600 static int rdac_bus_attach(struct scsi_device *sdev);
 601 static void rdac_bus_detach(struct scsi_device *sdev);
 602
 603 static struct scsi_device_handler rdac_dh = {
 604         .name = RDAC_NAME,
 605         .module = THIS_MODULE,
 606         .devlist = rdac_dev_list,
 607         .prep_fn = rdac_prep_fn,
 608         .check_sense = rdac_check_sense,
 609         .attach = rdac_bus_attach,
 610         .detach = rdac_bus_detach,
 611         .activate = rdac_activate,
 612 };
 613
 614 static int rdac_bus_attach(struct scsi_device *sdev)
 615 {
 616         struct scsi_dh_data *scsi_dh_data;
 617         struct rdac_dh_data *h;
 618         unsigned long flags;
 619         int err;
 620
 621         scsi_dh_data = kzalloc(sizeof(struct scsi_device_handler *)
 622                                + sizeof(*h) , GFP_KERNEL);
 623         if (!scsi_dh_data) {
 624                 sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n",
 625                             RDAC_NAME);
 626                 return 0;
 627         }
 628
 629         scsi_dh_data->scsi_dh = &rdac_dh;
 630         h = (struct rdac_dh_data *) scsi_dh_data->buf;
 631         h->lun = UNINITIALIZED_LUN;
 632         h->state = RDAC_STATE_ACTIVE;
 633
 634         err = get_lun(sdev, h);
 635         if (err != SCSI_DH_OK)
 636                 goto failed;
 637
 638         err = check_ownership(sdev, h);
 639         if (err != SCSI_DH_OK)
 640                 goto failed;
 641
 642         if (!try_module_get(THIS_MODULE))
 643                 goto failed;
 644
 645         spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
 646         sdev->scsi_dh_data = scsi_dh_data;
 647         spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
 648
 649         sdev_printk(KERN_NOTICE, sdev,
 650                     "%s: LUN %d (%s)\n",
 651                     RDAC_NAME, h->lun, lun_state[(int)h->lun_state]);
 652
 653         return 0;
 654
 655 failed:
 656         kfree(scsi_dh_data);
 657         sdev_printk(KERN_ERR, sdev, "%s: not attached\n",
 658                     RDAC_NAME);
 659         return -EINVAL;
 660 }
 661
 662 static void rdac_bus_detach( struct scsi_device *sdev )
 663 {
 664         struct scsi_dh_data *scsi_dh_data;
 665         struct rdac_dh_data *h;
 666         unsigned long flags;
 667
 668         spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
 669         scsi_dh_data = sdev->scsi_dh_data;
 670         sdev->scsi_dh_data = NULL;
 671         spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
 672
 673         h = (struct rdac_dh_data *) scsi_dh_data->buf;
 674         if (h->ctlr)
 675                 kref_put(&h->ctlr->kref, release_controller);
 676         kfree(scsi_dh_data);
 677         module_put(THIS_MODULE);
 678         sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", RDAC_NAME);
 679 }
 680
 681
 682
 683 static int __init rdac_init(void)
 684 {
 685         int r;
 686
 687         r = scsi_register_device_handler(&rdac_dh);
 688         if (r != 0)
 689                 printk(KERN_ERR "Failed to register scsi device handler.");
 690         return r;
 691 }
 692
 693 static void __exit rdac_exit(void)
 694 {
 695         scsi_unregister_device_handler(&rdac_dh);
 696 }
 697
 698 module_init(rdac_init);
 699 module_exit(rdac_exit);
 700
 701 MODULE_DESCRIPTION("Multipath LSI/Engenio RDAC driver");
 702 MODULE_AUTHOR("Mike Christie, Chandra Seetharaman");
 703 MODULE_LICENSE("GPL");