drivers/md/dm-mpath-rdac.c

   1 /*
   2  * Engenio/LSI RDAC DM HW 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_cmnd.h>
  24 #include <scsi/scsi_eh.h>
  25
  26 #define DM_MSG_PREFIX "multipath rdac"
  27
  28 #include "dm.h"
  29 #include "dm-hw-handler.h"
  30
  31 #define RDAC_DM_HWH_NAME "rdac"
  32 #define RDAC_DM_HWH_VER "0.4"
  33
  34 /*
  35  * LSI mode page stuff
  36  *
  37  * These struct definitions and the forming of the
  38  * mode page were taken from the LSI RDAC 2.4 GPL'd
  39  * driver, and then converted to Linux conventions.
  40  */
  41 #define RDAC_QUIESCENCE_TIME 20;
  42 /*
  43  * Page Codes
  44  */
  45 #define RDAC_PAGE_CODE_REDUNDANT_CONTROLLER 0x2c
  46
  47 /*
  48  * Controller modes definitions
  49  */
  50 #define RDAC_MODE_TRANSFER_ALL_LUNS             0x01
  51 #define RDAC_MODE_TRANSFER_SPECIFIED_LUNS       0x02
  52
  53 /*
  54  * RDAC Options field
  55  */
  56 #define RDAC_FORCED_QUIESENCE 0x02
  57
  58 #define RDAC_FAILOVER_TIMEOUT (60 * HZ)
  59
  60 struct rdac_mode_6_hdr {
  61         u8      data_len;
  62         u8      medium_type;
  63         u8      device_params;
  64         u8      block_desc_len;
  65 };
  66
  67 struct rdac_mode_10_hdr {
  68         u16     data_len;
  69         u8      medium_type;
  70         u8      device_params;
  71         u16     reserved;
  72         u16     block_desc_len;
  73 };
  74
  75 struct rdac_mode_common {
  76         u8      controller_serial[16];
  77         u8      alt_controller_serial[16];
  78         u8      rdac_mode[2];
  79         u8      alt_rdac_mode[2];
  80         u8      quiescence_timeout;
  81         u8      rdac_options;
  82 };
  83
  84 struct rdac_pg_legacy {
  85         struct rdac_mode_6_hdr hdr;
  86         u8      page_code;
  87         u8      page_len;
  88         struct rdac_mode_common common;
  89 #define MODE6_MAX_LUN   32
  90         u8      lun_table[MODE6_MAX_LUN];
  91         u8      reserved2[32];
  92         u8      reserved3;
  93         u8      reserved4;
  94 };
  95
  96 struct rdac_pg_expanded {
  97         struct rdac_mode_10_hdr hdr;
  98         u8      page_code;
  99         u8      subpage_code;
 100         u8      page_len[2];
 101         struct rdac_mode_common common;
 102         u8      lun_table[256];
 103         u8      reserved3;
 104         u8      reserved4;
 105 };
 106
 107 struct c9_inquiry {
 108         u8      peripheral_info;
 109         u8      page_code;      /* 0xC9 */
 110         u8      reserved1;
 111         u8      page_len;
 112         u8      page_id[4];     /* "vace" */
 113         u8      avte_cvp;
 114         u8      path_prio;
 115         u8      reserved2[38];
 116 };
 117
 118 #define SUBSYS_ID_LEN   16
 119 #define SLOT_ID_LEN     2
 120
 121 struct c4_inquiry {
 122         u8      peripheral_info;
 123         u8      page_code;      /* 0xC4 */
 124         u8      reserved1;
 125         u8      page_len;
 126         u8      page_id[4];     /* "subs" */
 127         u8      subsys_id[SUBSYS_ID_LEN];
 128         u8      revision[4];
 129         u8      slot_id[SLOT_ID_LEN];
 130         u8      reserved[2];
 131 };
 132
 133 struct rdac_controller {
 134         u8                      subsys_id[SUBSYS_ID_LEN];
 135         u8                      slot_id[SLOT_ID_LEN];
 136         int                     use_10_ms;
 137         struct kref             kref;
 138         struct list_head        node; /* list of all controllers */
 139         spinlock_t              lock;
 140         int                     submitted;
 141         struct list_head        cmd_list; /* list of commands to be submitted */
 142         union                   {
 143                 struct rdac_pg_legacy legacy;
 144                 struct rdac_pg_expanded expanded;
 145         } mode_select;
 146 };
 147 struct c8_inquiry {
 148         u8      peripheral_info;
 149         u8      page_code; /* 0xC8 */
 150         u8      reserved1;
 151         u8      page_len;
 152         u8      page_id[4]; /* "edid" */
 153         u8      reserved2[3];
 154         u8      vol_uniq_id_len;
 155         u8      vol_uniq_id[16];
 156         u8      vol_user_label_len;
 157         u8      vol_user_label[60];
 158         u8      array_uniq_id_len;
 159         u8      array_unique_id[16];
 160         u8      array_user_label_len;
 161         u8      array_user_label[60];
 162         u8      lun[8];
 163 };
 164
 165 struct c2_inquiry {
 166         u8      peripheral_info;
 167         u8      page_code;      /* 0xC2 */
 168         u8      reserved1;
 169         u8      page_len;
 170         u8      page_id[4];     /* "swr4" */
 171         u8      sw_version[3];
 172         u8      sw_date[3];
 173         u8      features_enabled;
 174         u8      max_lun_supported;
 175         u8      partitions[239]; /* Total allocation length should be 0xFF */
 176 };
 177
 178 struct rdac_handler {
 179         struct list_head        entry; /* list waiting to submit MODE SELECT */
 180         unsigned                timeout;
 181         struct rdac_controller  *ctlr;
 182 #define UNINITIALIZED_LUN       (1 << 8)
 183         unsigned                lun;
 184         unsigned char           sense[SCSI_SENSE_BUFFERSIZE];
 185         struct dm_path          *path;
 186         struct work_struct      work;
 187 #define SEND_C2_INQUIRY         1
 188 #define SEND_C4_INQUIRY         2
 189 #define SEND_C8_INQUIRY         3
 190 #define SEND_C9_INQUIRY         4
 191 #define SEND_MODE_SELECT        5
 192         int                     cmd_to_send;
 193         union                   {
 194                 struct c2_inquiry c2;
 195                 struct c4_inquiry c4;
 196                 struct c8_inquiry c8;
 197                 struct c9_inquiry c9;
 198         } inq;
 199 };
 200
 201 static LIST_HEAD(ctlr_list);
 202 static DEFINE_SPINLOCK(list_lock);
 203 static struct workqueue_struct *rdac_wkqd;
 204
 205 static inline int had_failures(struct request *req, int error)
 206 {
 207         return (error || host_byte(req->errors) != DID_OK ||
 208                         msg_byte(req->errors) != COMMAND_COMPLETE);
 209 }
 210
 211 static void rdac_resubmit_all(struct rdac_handler *h)
 212 {
 213         struct rdac_controller *ctlr = h->ctlr;
 214         struct rdac_handler *tmp, *h1;
 215
 216         spin_lock(&ctlr->lock);
 217         list_for_each_entry_safe(h1, tmp, &ctlr->cmd_list, entry) {
 218                 h1->cmd_to_send = SEND_C9_INQUIRY;
 219                 queue_work(rdac_wkqd, &h1->work);
 220                 list_del(&h1->entry);
 221         }
 222         ctlr->submitted = 0;
 223         spin_unlock(&ctlr->lock);
 224 }
 225
 226 static void mode_select_endio(struct request *req, int error)
 227 {
 228         struct rdac_handler *h = req->end_io_data;
 229         struct scsi_sense_hdr sense_hdr;
 230         int sense = 0, fail = 0;
 231
 232         if (had_failures(req, error)) {
 233                 fail = 1;
 234                 goto failed;
 235         }
 236
 237         if (status_byte(req->errors) == CHECK_CONDITION) {
 238                 scsi_normalize_sense(req->sense, SCSI_SENSE_BUFFERSIZE,
 239                                 &sense_hdr);
 240                 sense = (sense_hdr.sense_key << 16) | (sense_hdr.asc << 8) |
 241                                 sense_hdr.ascq;
 242                 /* If it is retryable failure, submit the c9 inquiry again */
 243                 if (sense == 0x59136 || sense == 0x68b02 || sense == 0xb8b02 ||
 244                     sense == 0x62900) {
 245                         /* 0x59136    - Command lock contention
 246                          * 0x[6b]8b02 - Quiesense in progress or achieved
 247                          * 0x62900    - Power On, Reset, or Bus Device Reset
 248                          */
 249                         h->cmd_to_send = SEND_C9_INQUIRY;
 250                         queue_work(rdac_wkqd, &h->work);
 251                         goto done;
 252                 }
 253                 if (sense)
 254                         DMINFO("MODE_SELECT failed on %s with sense 0x%x",
 255                                                 h->path->dev->name, sense);
 256         }
 257 failed:
 258         if (fail || sense)
 259                 dm_pg_init_complete(h->path, MP_FAIL_PATH);
 260         else
 261                 dm_pg_init_complete(h->path, 0);
 262
 263 done:
 264         rdac_resubmit_all(h);
 265         __blk_put_request(req->q, req);
 266 }
 267
 268 static struct request *get_rdac_req(struct rdac_handler *h,
 269                         void *buffer, unsigned buflen, int rw)
 270 {
 271         struct request *rq;
 272         struct request_queue *q = bdev_get_queue(h->path->dev->bdev);
 273
 274         rq = blk_get_request(q, rw, GFP_KERNEL);
 275
 276         if (!rq) {
 277                 DMINFO("get_rdac_req: blk_get_request failed");
 278                 return NULL;
 279         }
 280
 281         if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_KERNEL)) {
 282                 blk_put_request(rq);
 283                 DMINFO("get_rdac_req: blk_rq_map_kern failed");
 284                 return NULL;
 285         }
 286
 287         rq->sense = h->sense;
 288         memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
 289         rq->sense_len = 0;
 290
 291         rq->end_io_data = h;
 292         rq->timeout = h->timeout;
 293         rq->cmd_type = REQ_TYPE_BLOCK_PC;
 294         rq->cmd_flags |= REQ_FAILFAST | REQ_NOMERGE;
 295         return rq;
 296 }
 297
 298 static struct request *rdac_failover_get(struct rdac_handler *h)
 299 {
 300         struct request *rq;
 301         struct rdac_mode_common *common;
 302         unsigned data_size;
 303
 304         if (h->ctlr->use_10_ms) {
 305                 struct rdac_pg_expanded *rdac_pg;
 306
 307                 data_size = sizeof(struct rdac_pg_expanded);
 308                 rdac_pg = &h->ctlr->mode_select.expanded;
 309                 memset(rdac_pg, 0, data_size);
 310                 common = &rdac_pg->common;
 311                 rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER + 0x40;
 312                 rdac_pg->subpage_code = 0x1;
 313                 rdac_pg->page_len[0] = 0x01;
 314                 rdac_pg->page_len[1] = 0x28;
 315                 rdac_pg->lun_table[h->lun] = 0x81;
 316         } else {
 317                 struct rdac_pg_legacy *rdac_pg;
 318
 319                 data_size = sizeof(struct rdac_pg_legacy);
 320                 rdac_pg = &h->ctlr->mode_select.legacy;
 321                 memset(rdac_pg, 0, data_size);
 322                 common = &rdac_pg->common;
 323                 rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER;
 324                 rdac_pg->page_len = 0x68;
 325                 rdac_pg->lun_table[h->lun] = 0x81;
 326         }
 327         common->rdac_mode[1] = RDAC_MODE_TRANSFER_SPECIFIED_LUNS;
 328         common->quiescence_timeout = RDAC_QUIESCENCE_TIME;
 329         common->rdac_options = RDAC_FORCED_QUIESENCE;
 330
 331         /* get request for block layer packet command */
 332         rq = get_rdac_req(h, &h->ctlr->mode_select, data_size, WRITE);
 333         if (!rq) {
 334                 DMERR("rdac_failover_get: no rq");
 335                 return NULL;
 336         }
 337
 338         /* Prepare the command. */
 339         if (h->ctlr->use_10_ms) {
 340                 rq->cmd[0] = MODE_SELECT_10;
 341                 rq->cmd[7] = data_size >> 8;
 342                 rq->cmd[8] = data_size & 0xff;
 343         } else {
 344                 rq->cmd[0] = MODE_SELECT;
 345                 rq->cmd[4] = data_size;
 346         }
 347         rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
 348
 349         return rq;
 350 }
 351
 352 /* Acquires h->ctlr->lock */
 353 static void submit_mode_select(struct rdac_handler *h)
 354 {
 355         struct request *rq;
 356         struct request_queue *q = bdev_get_queue(h->path->dev->bdev);
 357
 358         spin_lock(&h->ctlr->lock);
 359         if (h->ctlr->submitted) {
 360                 list_add(&h->entry, &h->ctlr->cmd_list);
 361                 goto drop_lock;
 362         }
 363
 364         if (!q) {
 365                 DMINFO("submit_mode_select: no queue");
 366                 goto fail_path;
 367         }
 368
 369         rq = rdac_failover_get(h);
 370         if (!rq) {
 371                 DMERR("submit_mode_select: no rq");
 372                 goto fail_path;
 373         }
 374
 375         DMINFO("queueing MODE_SELECT command on %s", h->path->dev->name);
 376
 377         blk_execute_rq_nowait(q, NULL, rq, 1, mode_select_endio);
 378         h->ctlr->submitted = 1;
 379         goto drop_lock;
 380 fail_path:
 381         dm_pg_init_complete(h->path, MP_FAIL_PATH);
 382 drop_lock:
 383         spin_unlock(&h->ctlr->lock);
 384 }
 385
 386 static void release_ctlr(struct kref *kref)
 387 {
 388         struct rdac_controller *ctlr;
 389         ctlr = container_of(kref, struct rdac_controller, kref);
 390
 391         spin_lock(&list_lock);
 392         list_del(&ctlr->node);
 393         spin_unlock(&list_lock);
 394         kfree(ctlr);
 395 }
 396
 397 static struct rdac_controller *get_controller(u8 *subsys_id, u8 *slot_id)
 398 {
 399         struct rdac_controller *ctlr, *tmp;
 400
 401         spin_lock(&list_lock);
 402
 403         list_for_each_entry(tmp, &ctlr_list, node) {
 404                 if ((memcmp(tmp->subsys_id, subsys_id, SUBSYS_ID_LEN) == 0) &&
 405                           (memcmp(tmp->slot_id, slot_id, SLOT_ID_LEN) == 0)) {
 406                         kref_get(&tmp->kref);
 407                         spin_unlock(&list_lock);
 408                         return tmp;
 409                 }
 410         }
 411         ctlr = kmalloc(sizeof(*ctlr), GFP_ATOMIC);
 412         if (!ctlr)
 413                 goto done;
 414
 415         /* initialize fields of controller */
 416         memcpy(ctlr->subsys_id, subsys_id, SUBSYS_ID_LEN);
 417         memcpy(ctlr->slot_id, slot_id, SLOT_ID_LEN);
 418         kref_init(&ctlr->kref);
 419         spin_lock_init(&ctlr->lock);
 420         ctlr->submitted = 0;
 421         ctlr->use_10_ms = -1;
 422         INIT_LIST_HEAD(&ctlr->cmd_list);
 423         list_add(&ctlr->node, &ctlr_list);
 424 done:
 425         spin_unlock(&list_lock);
 426         return ctlr;
 427 }
 428
 429 static void c4_endio(struct request *req, int error)
 430 {
 431         struct rdac_handler *h = req->end_io_data;
 432         struct c4_inquiry *sp;
 433
 434         if (had_failures(req, error)) {
 435                 dm_pg_init_complete(h->path, MP_FAIL_PATH);
 436                 goto done;
 437         }
 438
 439         sp = &h->inq.c4;
 440
 441         h->ctlr = get_controller(sp->subsys_id, sp->slot_id);
 442
 443         if (h->ctlr) {
 444                 h->cmd_to_send = SEND_C9_INQUIRY;
 445                 queue_work(rdac_wkqd, &h->work);
 446         } else
 447                 dm_pg_init_complete(h->path, MP_FAIL_PATH);
 448 done:
 449         __blk_put_request(req->q, req);
 450 }
 451
 452 static void c2_endio(struct request *req, int error)
 453 {
 454         struct rdac_handler *h = req->end_io_data;
 455         struct c2_inquiry *sp;
 456
 457         if (had_failures(req, error)) {
 458                 dm_pg_init_complete(h->path, MP_FAIL_PATH);
 459                 goto done;
 460         }
 461
 462         sp = &h->inq.c2;
 463
 464         /* If more than MODE6_MAX_LUN luns are supported, use mode select 10 */
 465         if (sp->max_lun_supported >= MODE6_MAX_LUN)
 466                 h->ctlr->use_10_ms = 1;
 467         else
 468                 h->ctlr->use_10_ms = 0;
 469
 470         h->cmd_to_send = SEND_MODE_SELECT;
 471         queue_work(rdac_wkqd, &h->work);
 472 done:
 473         __blk_put_request(req->q, req);
 474 }
 475
 476 static void c9_endio(struct request *req, int error)
 477 {
 478         struct rdac_handler *h = req->end_io_data;
 479         struct c9_inquiry *sp;
 480
 481         if (had_failures(req, error)) {
 482                 dm_pg_init_complete(h->path, MP_FAIL_PATH);
 483                 goto done;
 484         }
 485
 486         /* We need to look at the sense keys here to take clear action.
 487          * For now simple logic: If the host is in AVT mode or if controller
 488          * owns the lun, return dm_pg_init_complete(), otherwise submit
 489          * MODE SELECT.
 490          */
 491         sp = &h->inq.c9;
 492
 493         /* If in AVT mode, return success */
 494         if ((sp->avte_cvp >> 7) == 0x1) {
 495                 dm_pg_init_complete(h->path, 0);
 496                 goto done;
 497         }
 498
 499         /* If the controller on this path owns the LUN, return success */
 500         if (sp->avte_cvp & 0x1) {
 501                 dm_pg_init_complete(h->path, 0);
 502                 goto done;
 503         }
 504
 505         if (h->ctlr) {
 506                 if (h->ctlr->use_10_ms == -1)
 507                         h->cmd_to_send = SEND_C2_INQUIRY;
 508                 else
 509                         h->cmd_to_send = SEND_MODE_SELECT;
 510         } else
 511                 h->cmd_to_send = SEND_C4_INQUIRY;
 512         queue_work(rdac_wkqd, &h->work);
 513 done:
 514         __blk_put_request(req->q, req);
 515 }
 516
 517 static void c8_endio(struct request *req, int error)
 518 {
 519         struct rdac_handler *h = req->end_io_data;
 520         struct c8_inquiry *sp;
 521
 522         if (had_failures(req, error)) {
 523                 dm_pg_init_complete(h->path, MP_FAIL_PATH);
 524                 goto done;
 525         }
 526
 527         /* We need to look at the sense keys here to take clear action.
 528          * For now simple logic: Get the lun from the inquiry page.
 529          */
 530         sp = &h->inq.c8;
 531         h->lun = sp->lun[7]; /* currently it uses only one byte */
 532         h->cmd_to_send = SEND_C9_INQUIRY;
 533         queue_work(rdac_wkqd, &h->work);
 534 done:
 535         __blk_put_request(req->q, req);
 536 }
 537
 538 static void submit_inquiry(struct rdac_handler *h, int page_code,
 539                 unsigned int len, rq_end_io_fn endio)
 540 {
 541         struct request *rq;
 542         struct request_queue *q = bdev_get_queue(h->path->dev->bdev);
 543
 544         if (!q)
 545                 goto fail_path;
 546
 547         rq = get_rdac_req(h, &h->inq, len, READ);
 548         if (!rq)
 549                 goto fail_path;
 550
 551         /* Prepare the command. */
 552         rq->cmd[0] = INQUIRY;
 553         rq->cmd[1] = 1;
 554         rq->cmd[2] = page_code;
 555         rq->cmd[4] = len;
 556         rq->cmd_len = COMMAND_SIZE(INQUIRY);
 557         blk_execute_rq_nowait(q, NULL, rq, 1, endio);
 558         return;
 559
 560 fail_path:
 561         dm_pg_init_complete(h->path, MP_FAIL_PATH);
 562 }
 563
 564 static void service_wkq(struct work_struct *work)
 565 {
 566         struct rdac_handler *h = container_of(work, struct rdac_handler, work);
 567
 568         switch (h->cmd_to_send) {
 569         case SEND_C2_INQUIRY:
 570                 submit_inquiry(h, 0xC2, sizeof(struct c2_inquiry), c2_endio);
 571                 break;
 572         case SEND_C4_INQUIRY:
 573                 submit_inquiry(h, 0xC4, sizeof(struct c4_inquiry), c4_endio);
 574                 break;
 575         case SEND_C8_INQUIRY:
 576                 submit_inquiry(h, 0xC8, sizeof(struct c8_inquiry), c8_endio);
 577                 break;
 578         case SEND_C9_INQUIRY:
 579                 submit_inquiry(h, 0xC9, sizeof(struct c9_inquiry), c9_endio);
 580                 break;
 581         case SEND_MODE_SELECT:
 582                 submit_mode_select(h);
 583                 break;
 584         default:
 585                 BUG();
 586         }
 587 }
 588 /*
 589  * only support subpage2c until we confirm that this is just a matter of
 590  * of updating firmware or not, and RDAC (basic AVT works already) for now
 591  * but we can add these in in when we get time and testers
 592  */
 593 static int rdac_create(struct hw_handler *hwh, unsigned argc, char **argv)
 594 {
 595         struct rdac_handler *h;
 596         unsigned timeout;
 597
 598         if (argc == 0) {
 599                 /* No arguments: use defaults */
 600                 timeout = RDAC_FAILOVER_TIMEOUT;
 601         } else if (argc != 1) {
 602                 DMWARN("incorrect number of arguments");
 603                 return -EINVAL;
 604         } else {
 605                 if (sscanf(argv[1], "%u", &timeout) != 1) {
 606                         DMWARN("invalid timeout value");
 607                         return -EINVAL;
 608                 }
 609         }
 610
 611         h = kzalloc(sizeof(*h), GFP_KERNEL);
 612         if (!h)
 613                 return -ENOMEM;
 614
 615         hwh->context = h;
 616         h->timeout = timeout;
 617         h->lun = UNINITIALIZED_LUN;
 618         INIT_WORK(&h->work, service_wkq);
 619         DMWARN("using RDAC command with timeout %u", h->timeout);
 620
 621         return 0;
 622 }
 623
 624 static void rdac_destroy(struct hw_handler *hwh)
 625 {
 626         struct rdac_handler *h = hwh->context;
 627
 628         if (h->ctlr)
 629                 kref_put(&h->ctlr->kref, release_ctlr);
 630         kfree(h);
 631         hwh->context = NULL;
 632 }
 633
 634 static unsigned rdac_error(struct hw_handler *hwh, struct bio *bio)
 635 {
 636         /* Try default handler */
 637         return dm_scsi_err_handler(hwh, bio);
 638 }
 639
 640 static void rdac_pg_init(struct hw_handler *hwh, unsigned bypassed,
 641                         struct dm_path *path)
 642 {
 643         struct rdac_handler *h = hwh->context;
 644
 645         h->path = path;
 646         switch (h->lun) {
 647         case UNINITIALIZED_LUN:
 648                 submit_inquiry(h, 0xC8, sizeof(struct c8_inquiry), c8_endio);
 649                 break;
 650         default:
 651                 submit_inquiry(h, 0xC9, sizeof(struct c9_inquiry), c9_endio);
 652         }
 653 }
 654
 655 static struct hw_handler_type rdac_handler = {
 656         .name = RDAC_DM_HWH_NAME,
 657         .module = THIS_MODULE,
 658         .create = rdac_create,
 659         .destroy = rdac_destroy,
 660         .pg_init = rdac_pg_init,
 661         .error = rdac_error,
 662 };
 663
 664 static int __init rdac_init(void)
 665 {
 666         int r;
 667
 668         rdac_wkqd = create_singlethread_workqueue("rdac_wkqd");
 669         if (!rdac_wkqd) {
 670                 DMERR("Failed to create workqueue rdac_wkqd.");
 671                 return -ENOMEM;
 672         }
 673
 674         r = dm_register_hw_handler(&rdac_handler);
 675         if (r < 0) {
 676                 DMERR("%s: register failed %d", RDAC_DM_HWH_NAME, r);
 677                 destroy_workqueue(rdac_wkqd);
 678                 return r;
 679         }
 680
 681         DMINFO("%s: version %s loaded", RDAC_DM_HWH_NAME, RDAC_DM_HWH_VER);
 682         return 0;
 683 }
 684
 685 static void __exit rdac_exit(void)
 686 {
 687         int r = dm_unregister_hw_handler(&rdac_handler);
 688
 689         destroy_workqueue(rdac_wkqd);
 690         if (r < 0)
 691                 DMERR("%s: unregister failed %d", RDAC_DM_HWH_NAME, r);
 692 }
 693
 694 module_init(rdac_init);
 695 module_exit(rdac_exit);
 696
 697 MODULE_DESCRIPTION("DM Multipath LSI/Engenio RDAC support");
 698 MODULE_AUTHOR("Mike Christie, Chandra Seetharaman");
 699 MODULE_LICENSE("GPL");
 700 MODULE_VERSION(RDAC_DM_HWH_VER);