drivers/scsi/device_handler/scsi_dh_alua.c

   1 /*
   2  * Generic SCSI-3 ALUA SCSI Device Handler
   3  *
   4  * Copyright (C) 2007-2010 Hannes Reinecke, SUSE Linux Products GmbH.
   5  * All rights reserved.
   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 <linux/slab.h>
  23 #include <linux/delay.h>
  24 #include <linux/module.h>
  25 #include <scsi/scsi.h>
  26 #include <scsi/scsi_eh.h>
  27 #include <scsi/scsi_dh.h>
  28
  29 #define ALUA_DH_NAME "alua"
  30 #define ALUA_DH_VER "1.3"
  31
  32 #define TPGS_STATE_OPTIMIZED            0x0
  33 #define TPGS_STATE_NONOPTIMIZED         0x1
  34 #define TPGS_STATE_STANDBY              0x2
  35 #define TPGS_STATE_UNAVAILABLE          0x3
  36 #define TPGS_STATE_LBA_DEPENDENT        0x4
  37 #define TPGS_STATE_OFFLINE              0xe
  38 #define TPGS_STATE_TRANSITIONING        0xf
  39
  40 #define TPGS_SUPPORT_NONE               0x00
  41 #define TPGS_SUPPORT_OPTIMIZED          0x01
  42 #define TPGS_SUPPORT_NONOPTIMIZED       0x02
  43 #define TPGS_SUPPORT_STANDBY            0x04
  44 #define TPGS_SUPPORT_UNAVAILABLE        0x08
  45 #define TPGS_SUPPORT_LBA_DEPENDENT      0x10
  46 #define TPGS_SUPPORT_OFFLINE            0x40
  47 #define TPGS_SUPPORT_TRANSITION         0x80
  48
  49 #define TPGS_MODE_UNINITIALIZED          -1
  50 #define TPGS_MODE_NONE                  0x0
  51 #define TPGS_MODE_IMPLICIT              0x1
  52 #define TPGS_MODE_EXPLICIT              0x2
  53
  54 #define ALUA_INQUIRY_SIZE               36
  55 #define ALUA_FAILOVER_TIMEOUT           (60 * HZ)
  56 #define ALUA_FAILOVER_RETRIES           5
  57
  58 struct alua_dh_data {
  59         int                     group_id;
  60         int                     rel_port;
  61         int                     tpgs;
  62         int                     state;
  63         unsigned char           inq[ALUA_INQUIRY_SIZE];
  64         unsigned char           *buff;
  65         int                     bufflen;
  66         unsigned char           sense[SCSI_SENSE_BUFFERSIZE];
  67         int                     senselen;
  68         struct scsi_device      *sdev;
  69         activate_complete       callback_fn;
  70         void                    *callback_data;
  71 };
  72
  73 #define ALUA_POLICY_SWITCH_CURRENT      0
  74 #define ALUA_POLICY_SWITCH_ALL          1
  75
  76 static char print_alua_state(int);
  77 static int alua_check_sense(struct scsi_device *, struct scsi_sense_hdr *);
  78
  79 static inline struct alua_dh_data *get_alua_data(struct scsi_device *sdev)
  80 {
  81         struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
  82         BUG_ON(scsi_dh_data == NULL);
  83         return ((struct alua_dh_data *) scsi_dh_data->buf);
  84 }
  85
  86 static int realloc_buffer(struct alua_dh_data *h, unsigned len)
  87 {
  88         if (h->buff && h->buff != h->inq)
  89                 kfree(h->buff);
  90
  91         h->buff = kmalloc(len, GFP_NOIO);
  92         if (!h->buff) {
  93                 h->buff = h->inq;
  94                 h->bufflen = ALUA_INQUIRY_SIZE;
  95                 return 1;
  96         }
  97         h->bufflen = len;
  98         return 0;
  99 }
 100
 101 static struct request *get_alua_req(struct scsi_device *sdev,
 102                                     void *buffer, unsigned buflen, int rw)
 103 {
 104         struct request *rq;
 105         struct request_queue *q = sdev->request_queue;
 106
 107         rq = blk_get_request(q, rw, GFP_NOIO);
 108
 109         if (!rq) {
 110                 sdev_printk(KERN_INFO, sdev,
 111                             "%s: blk_get_request failed\n", __func__);
 112                 return NULL;
 113         }
 114
 115         if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_NOIO)) {
 116                 blk_put_request(rq);
 117                 sdev_printk(KERN_INFO, sdev,
 118                             "%s: blk_rq_map_kern failed\n", __func__);
 119                 return NULL;
 120         }
 121
 122         rq->cmd_type = REQ_TYPE_BLOCK_PC;
 123         rq->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
 124                          REQ_FAILFAST_DRIVER;
 125         rq->retries = ALUA_FAILOVER_RETRIES;
 126         rq->timeout = ALUA_FAILOVER_TIMEOUT;
 127
 128         return rq;
 129 }
 130
 131 /*
 132  * submit_std_inquiry - Issue a standard INQUIRY command
 133  * @sdev: sdev the command should be send to
 134  */
 135 static int submit_std_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 136 {
 137         struct request *rq;
 138         int err = SCSI_DH_RES_TEMP_UNAVAIL;
 139
 140         rq = get_alua_req(sdev, h->inq, ALUA_INQUIRY_SIZE, READ);
 141         if (!rq)
 142                 goto done;
 143
 144         /* Prepare the command. */
 145         rq->cmd[0] = INQUIRY;
 146         rq->cmd[1] = 0;
 147         rq->cmd[2] = 0;
 148         rq->cmd[4] = ALUA_INQUIRY_SIZE;
 149         rq->cmd_len = COMMAND_SIZE(INQUIRY);
 150
 151         rq->sense = h->sense;
 152         memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
 153         rq->sense_len = h->senselen = 0;
 154
 155         err = blk_execute_rq(rq->q, NULL, rq, 1);
 156         if (err == -EIO) {
 157                 sdev_printk(KERN_INFO, sdev,
 158                             "%s: std inquiry failed with %x\n",
 159                             ALUA_DH_NAME, rq->errors);
 160                 h->senselen = rq->sense_len;
 161                 err = SCSI_DH_IO;
 162         }
 163         blk_put_request(rq);
 164 done:
 165         return err;
 166 }
 167
 168 /*
 169  * submit_vpd_inquiry - Issue an INQUIRY VPD page 0x83 command
 170  * @sdev: sdev the command should be sent to
 171  */
 172 static int submit_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 173 {
 174         struct request *rq;
 175         int err = SCSI_DH_RES_TEMP_UNAVAIL;
 176
 177         rq = get_alua_req(sdev, h->buff, h->bufflen, READ);
 178         if (!rq)
 179                 goto done;
 180
 181         /* Prepare the command. */
 182         rq->cmd[0] = INQUIRY;
 183         rq->cmd[1] = 1;
 184         rq->cmd[2] = 0x83;
 185         rq->cmd[4] = h->bufflen;
 186         rq->cmd_len = COMMAND_SIZE(INQUIRY);
 187
 188         rq->sense = h->sense;
 189         memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
 190         rq->sense_len = h->senselen = 0;
 191
 192         err = blk_execute_rq(rq->q, NULL, rq, 1);
 193         if (err == -EIO) {
 194                 sdev_printk(KERN_INFO, sdev,
 195                             "%s: evpd inquiry failed with %x\n",
 196                             ALUA_DH_NAME, rq->errors);
 197                 h->senselen = rq->sense_len;
 198                 err = SCSI_DH_IO;
 199         }
 200         blk_put_request(rq);
 201 done:
 202         return err;
 203 }
 204
 205 /*
 206  * submit_rtpg - Issue a REPORT TARGET GROUP STATES command
 207  * @sdev: sdev the command should be sent to
 208  */
 209 static unsigned submit_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
 210 {
 211         struct request *rq;
 212         int err = SCSI_DH_RES_TEMP_UNAVAIL;
 213
 214         rq = get_alua_req(sdev, h->buff, h->bufflen, READ);
 215         if (!rq)
 216                 goto done;
 217
 218         /* Prepare the command. */
 219         rq->cmd[0] = MAINTENANCE_IN;
 220         rq->cmd[1] = MI_REPORT_TARGET_PGS;
 221         rq->cmd[6] = (h->bufflen >> 24) & 0xff;
 222         rq->cmd[7] = (h->bufflen >> 16) & 0xff;
 223         rq->cmd[8] = (h->bufflen >>  8) & 0xff;
 224         rq->cmd[9] = h->bufflen & 0xff;
 225         rq->cmd_len = COMMAND_SIZE(MAINTENANCE_IN);
 226
 227         rq->sense = h->sense;
 228         memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
 229         rq->sense_len = h->senselen = 0;
 230
 231         err = blk_execute_rq(rq->q, NULL, rq, 1);
 232         if (err == -EIO) {
 233                 sdev_printk(KERN_INFO, sdev,
 234                             "%s: rtpg failed with %x\n",
 235                             ALUA_DH_NAME, rq->errors);
 236                 h->senselen = rq->sense_len;
 237                 err = SCSI_DH_IO;
 238         }
 239         blk_put_request(rq);
 240 done:
 241         return err;
 242 }
 243
 244 /*
 245  * alua_stpg - Evaluate SET TARGET GROUP STATES
 246  * @sdev: the device to be evaluated
 247  * @state: the new target group state
 248  *
 249  * Send a SET TARGET GROUP STATES command to the device.
 250  * We only have to test here if we should resubmit the command;
 251  * any other error is assumed as a failure.
 252  */
 253 static void stpg_endio(struct request *req, int error)
 254 {
 255         struct alua_dh_data *h = req->end_io_data;
 256         struct scsi_sense_hdr sense_hdr;
 257         unsigned err = SCSI_DH_OK;
 258
 259         if (error || host_byte(req->errors) != DID_OK ||
 260                         msg_byte(req->errors) != COMMAND_COMPLETE) {
 261                 err = SCSI_DH_IO;
 262                 goto done;
 263         }
 264
 265         if (h->senselen > 0) {
 266                 err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
 267                                            &sense_hdr);
 268                 if (!err) {
 269                         err = SCSI_DH_IO;
 270                         goto done;
 271                 }
 272                 err = alua_check_sense(h->sdev, &sense_hdr);
 273                 if (err == ADD_TO_MLQUEUE) {
 274                         err = SCSI_DH_RETRY;
 275                         goto done;
 276                 }
 277                 sdev_printk(KERN_INFO, h->sdev,
 278                             "%s: stpg sense code: %02x/%02x/%02x\n",
 279                             ALUA_DH_NAME, sense_hdr.sense_key,
 280                             sense_hdr.asc, sense_hdr.ascq);
 281                 err = SCSI_DH_IO;
 282         }
 283         if (err == SCSI_DH_OK) {
 284                 h->state = TPGS_STATE_OPTIMIZED;
 285                 sdev_printk(KERN_INFO, h->sdev,
 286                             "%s: port group %02x switched to state %c\n",
 287                             ALUA_DH_NAME, h->group_id,
 288                             print_alua_state(h->state));
 289         }
 290 done:
 291         req->end_io_data = NULL;
 292         __blk_put_request(req->q, req);
 293         if (h->callback_fn) {
 294                 h->callback_fn(h->callback_data, err);
 295                 h->callback_fn = h->callback_data = NULL;
 296         }
 297         return;
 298 }
 299
 300 /*
 301  * submit_stpg - Issue a SET TARGET GROUP STATES command
 302  *
 303  * Currently we're only setting the current target port group state
 304  * to 'active/optimized' and let the array firmware figure out
 305  * the states of the remaining groups.
 306  */
 307 static unsigned submit_stpg(struct alua_dh_data *h)
 308 {
 309         struct request *rq;
 310         int stpg_len = 8;
 311         struct scsi_device *sdev = h->sdev;
 312
 313         /* Prepare the data buffer */
 314         memset(h->buff, 0, stpg_len);
 315         h->buff[4] = TPGS_STATE_OPTIMIZED & 0x0f;
 316         h->buff[6] = (h->group_id >> 8) & 0xff;
 317         h->buff[7] = h->group_id & 0xff;
 318
 319         rq = get_alua_req(sdev, h->buff, stpg_len, WRITE);
 320         if (!rq)
 321                 return SCSI_DH_RES_TEMP_UNAVAIL;
 322
 323         /* Prepare the command. */
 324         rq->cmd[0] = MAINTENANCE_OUT;
 325         rq->cmd[1] = MO_SET_TARGET_PGS;
 326         rq->cmd[6] = (stpg_len >> 24) & 0xff;
 327         rq->cmd[7] = (stpg_len >> 16) & 0xff;
 328         rq->cmd[8] = (stpg_len >>  8) & 0xff;
 329         rq->cmd[9] = stpg_len & 0xff;
 330         rq->cmd_len = COMMAND_SIZE(MAINTENANCE_OUT);
 331
 332         rq->sense = h->sense;
 333         memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
 334         rq->sense_len = h->senselen = 0;
 335         rq->end_io_data = h;
 336
 337         blk_execute_rq_nowait(rq->q, NULL, rq, 1, stpg_endio);
 338         return SCSI_DH_OK;
 339 }
 340
 341 /*
 342  * alua_std_inquiry - Evaluate standard INQUIRY command
 343  * @sdev: device to be checked
 344  *
 345  * Just extract the TPGS setting to find out if ALUA
 346  * is supported.
 347  */
 348 static int alua_std_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 349 {
 350         int err;
 351
 352         err = submit_std_inquiry(sdev, h);
 353
 354         if (err != SCSI_DH_OK)
 355                 return err;
 356
 357         /* Check TPGS setting */
 358         h->tpgs = (h->inq[5] >> 4) & 0x3;
 359         switch (h->tpgs) {
 360         case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT:
 361                 sdev_printk(KERN_INFO, sdev,
 362                             "%s: supports implicit and explicit TPGS\n",
 363                             ALUA_DH_NAME);
 364                 break;
 365         case TPGS_MODE_EXPLICIT:
 366                 sdev_printk(KERN_INFO, sdev, "%s: supports explicit TPGS\n",
 367                             ALUA_DH_NAME);
 368                 break;
 369         case TPGS_MODE_IMPLICIT:
 370                 sdev_printk(KERN_INFO, sdev, "%s: supports implicit TPGS\n",
 371                             ALUA_DH_NAME);
 372                 break;
 373         default:
 374                 h->tpgs = TPGS_MODE_NONE;
 375                 sdev_printk(KERN_INFO, sdev, "%s: not supported\n",
 376                             ALUA_DH_NAME);
 377                 err = SCSI_DH_DEV_UNSUPP;
 378                 break;
 379         }
 380
 381         return err;
 382 }
 383
 384 /*
 385  * alua_vpd_inquiry - Evaluate INQUIRY vpd page 0x83
 386  * @sdev: device to be checked
 387  *
 388  * Extract the relative target port and the target port group
 389  * descriptor from the list of identificators.
 390  */
 391 static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 392 {
 393         int len;
 394         unsigned err;
 395         unsigned char *d;
 396
 397  retry:
 398         err = submit_vpd_inquiry(sdev, h);
 399
 400         if (err != SCSI_DH_OK)
 401                 return err;
 402
 403         /* Check if vpd page exceeds initial buffer */
 404         len = (h->buff[2] << 8) + h->buff[3] + 4;
 405         if (len > h->bufflen) {
 406                 /* Resubmit with the correct length */
 407                 if (realloc_buffer(h, len)) {
 408                         sdev_printk(KERN_WARNING, sdev,
 409                                     "%s: kmalloc buffer failed\n",
 410                                     ALUA_DH_NAME);
 411                         /* Temporary failure, bypass */
 412                         return SCSI_DH_DEV_TEMP_BUSY;
 413                 }
 414                 goto retry;
 415         }
 416
 417         /*
 418          * Now look for the correct descriptor.
 419          */
 420         d = h->buff + 4;
 421         while (d < h->buff + len) {
 422                 switch (d[1] & 0xf) {
 423                 case 0x4:
 424                         /* Relative target port */
 425                         h->rel_port = (d[6] << 8) + d[7];
 426                         break;
 427                 case 0x5:
 428                         /* Target port group */
 429                         h->group_id = (d[6] << 8) + d[7];
 430                         break;
 431                 default:
 432                         break;
 433                 }
 434                 d += d[3] + 4;
 435         }
 436
 437         if (h->group_id == -1) {
 438                 /*
 439                  * Internal error; TPGS supported but required
 440                  * VPD identification descriptors not present.
 441                  * Disable ALUA support
 442                  */
 443                 sdev_printk(KERN_INFO, sdev,
 444                             "%s: No target port descriptors found\n",
 445                             ALUA_DH_NAME);
 446                 h->state = TPGS_STATE_OPTIMIZED;
 447                 h->tpgs = TPGS_MODE_NONE;
 448                 err = SCSI_DH_DEV_UNSUPP;
 449         } else {
 450                 sdev_printk(KERN_INFO, sdev,
 451                             "%s: port group %02x rel port %02x\n",
 452                             ALUA_DH_NAME, h->group_id, h->rel_port);
 453         }
 454
 455         return err;
 456 }
 457
 458 static char print_alua_state(int state)
 459 {
 460         switch (state) {
 461         case TPGS_STATE_OPTIMIZED:
 462                 return 'A';
 463         case TPGS_STATE_NONOPTIMIZED:
 464                 return 'N';
 465         case TPGS_STATE_STANDBY:
 466                 return 'S';
 467         case TPGS_STATE_UNAVAILABLE:
 468                 return 'U';
 469         case TPGS_STATE_LBA_DEPENDENT:
 470                 return 'L';
 471         case TPGS_STATE_OFFLINE:
 472                 return 'O';
 473         case TPGS_STATE_TRANSITIONING:
 474                 return 'T';
 475         default:
 476                 return 'X';
 477         }
 478 }
 479
 480 static int alua_check_sense(struct scsi_device *sdev,
 481                             struct scsi_sense_hdr *sense_hdr)
 482 {
 483         switch (sense_hdr->sense_key) {
 484         case NOT_READY:
 485                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a)
 486                         /*
 487                          * LUN Not Accessible - ALUA state transition
 488                          */
 489                         return ADD_TO_MLQUEUE;
 490                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0b)
 491                         /*
 492                          * LUN Not Accessible -- Target port in standby state
 493                          */
 494                         return SUCCESS;
 495                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0c)
 496                         /*
 497                          * LUN Not Accessible -- Target port in unavailable state
 498                          */
 499                         return SUCCESS;
 500                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x12)
 501                         /*
 502                          * LUN Not Ready -- Offline
 503                          */
 504                         return SUCCESS;
 505                 break;
 506         case UNIT_ATTENTION:
 507                 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
 508                         /*
 509                          * Power On, Reset, or Bus Device Reset, just retry.
 510                          */
 511                         return ADD_TO_MLQUEUE;
 512                 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) {
 513                         /*
 514                          * ALUA state changed
 515                          */
 516                         return ADD_TO_MLQUEUE;
 517                 }
 518                 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) {
 519                         /*
 520                          * Implicit ALUA state transition failed
 521                          */
 522                         return ADD_TO_MLQUEUE;
 523                 }
 524                 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x0e) {
 525                         /*
 526                          * REPORTED_LUNS_DATA_HAS_CHANGED is reported
 527                          * when switching controllers on targets like
 528                          * Intel Multi-Flex. We can just retry.
 529                          */
 530                         return ADD_TO_MLQUEUE;
 531                 }
 532
 533                 break;
 534         }
 535
 536         return SCSI_RETURN_NOT_HANDLED;
 537 }
 538
 539 /*
 540  * alua_rtpg - Evaluate REPORT TARGET GROUP STATES
 541  * @sdev: the device to be evaluated.
 542  *
 543  * Evaluate the Target Port Group State.
 544  * Returns SCSI_DH_DEV_OFFLINED if the path is
 545  * found to be unusable.
 546  */
 547 static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
 548 {
 549         struct scsi_sense_hdr sense_hdr;
 550         int len, k, off, valid_states = 0;
 551         char *ucp;
 552         unsigned err;
 553         unsigned long expiry, interval = 10;
 554
 555         expiry = round_jiffies_up(jiffies + ALUA_FAILOVER_TIMEOUT);
 556  retry:
 557         err = submit_rtpg(sdev, h);
 558
 559         if (err == SCSI_DH_IO && h->senselen > 0) {
 560                 err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
 561                                            &sense_hdr);
 562                 if (!err)
 563                         return SCSI_DH_IO;
 564
 565                 err = alua_check_sense(sdev, &sense_hdr);
 566                 if (err == ADD_TO_MLQUEUE && time_before(jiffies, expiry))
 567                         goto retry;
 568                 sdev_printk(KERN_INFO, sdev,
 569                             "%s: rtpg sense code %02x/%02x/%02x\n",
 570                             ALUA_DH_NAME, sense_hdr.sense_key,
 571                             sense_hdr.asc, sense_hdr.ascq);
 572                 err = SCSI_DH_IO;
 573         }
 574         if (err != SCSI_DH_OK)
 575                 return err;
 576
 577         len = (h->buff[0] << 24) + (h->buff[1] << 16) +
 578                 (h->buff[2] << 8) + h->buff[3] + 4;
 579
 580         if (len > h->bufflen) {
 581                 /* Resubmit with the correct length */
 582                 if (realloc_buffer(h, len)) {
 583                         sdev_printk(KERN_WARNING, sdev,
 584                                     "%s: kmalloc buffer failed\n",__func__);
 585                         /* Temporary failure, bypass */
 586                         return SCSI_DH_DEV_TEMP_BUSY;
 587                 }
 588                 goto retry;
 589         }
 590
 591         for (k = 4, ucp = h->buff + 4; k < len; k += off, ucp += off) {
 592                 if (h->group_id == (ucp[2] << 8) + ucp[3]) {
 593                         h->state = ucp[0] & 0x0f;
 594                         valid_states = ucp[1];
 595                 }
 596                 off = 8 + (ucp[7] * 4);
 597         }
 598
 599         sdev_printk(KERN_INFO, sdev,
 600                     "%s: port group %02x state %c supports %c%c%c%c%c%c%c\n",
 601                     ALUA_DH_NAME, h->group_id, print_alua_state(h->state),
 602                     valid_states&TPGS_SUPPORT_TRANSITION?'T':'t',
 603                     valid_states&TPGS_SUPPORT_OFFLINE?'O':'o',
 604                     valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l',
 605                     valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u',
 606                     valid_states&TPGS_SUPPORT_STANDBY?'S':'s',
 607                     valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n',
 608                     valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a');
 609
 610         switch (h->state) {
 611         case TPGS_STATE_TRANSITIONING:
 612                 if (time_before(jiffies, expiry)) {
 613                         /* State transition, retry */
 614                         interval *= 10;
 615                         msleep(interval);
 616                         goto retry;
 617                 }
 618                 /* Transitioning time exceeded, set port to standby */
 619                 err = SCSI_DH_RETRY;
 620                 h->state = TPGS_STATE_STANDBY;
 621                 break;
 622         case TPGS_STATE_OFFLINE:
 623         case TPGS_STATE_UNAVAILABLE:
 624                 /* Path unusable for unavailable/offline */
 625                 err = SCSI_DH_DEV_OFFLINED;
 626                 break;
 627         default:
 628                 /* Useable path if active */
 629                 err = SCSI_DH_OK;
 630                 break;
 631         }
 632         return err;
 633 }
 634
 635 /*
 636  * alua_initialize - Initialize ALUA state
 637  * @sdev: the device to be initialized
 638  *
 639  * For the prep_fn to work correctly we have
 640  * to initialize the ALUA state for the device.
 641  */
 642 static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h)
 643 {
 644         int err;
 645
 646         err = alua_std_inquiry(sdev, h);
 647         if (err != SCSI_DH_OK)
 648                 goto out;
 649
 650         err = alua_vpd_inquiry(sdev, h);
 651         if (err != SCSI_DH_OK)
 652                 goto out;
 653
 654         err = alua_rtpg(sdev, h);
 655         if (err != SCSI_DH_OK)
 656                 goto out;
 657
 658 out:
 659         return err;
 660 }
 661
 662 /*
 663  * alua_activate - activate a path
 664  * @sdev: device on the path to be activated
 665  *
 666  * We're currently switching the port group to be activated only and
 667  * let the array figure out the rest.
 668  * There may be other arrays which require us to switch all port groups
 669  * based on a certain policy. But until we actually encounter them it
 670  * should be okay.
 671  */
 672 static int alua_activate(struct scsi_device *sdev,
 673                         activate_complete fn, void *data)
 674 {
 675         struct alua_dh_data *h = get_alua_data(sdev);
 676         int err = SCSI_DH_OK;
 677
 678         if (h->group_id != -1) {
 679                 err = alua_rtpg(sdev, h);
 680                 if (err != SCSI_DH_OK)
 681                         goto out;
 682         }
 683
 684         if (h->tpgs & TPGS_MODE_EXPLICIT &&
 685             h->state != TPGS_STATE_OPTIMIZED &&
 686             h->state != TPGS_STATE_LBA_DEPENDENT) {
 687                 h->callback_fn = fn;
 688                 h->callback_data = data;
 689                 err = submit_stpg(h);
 690                 if (err == SCSI_DH_OK)
 691                         return 0;
 692                 h->callback_fn = h->callback_data = NULL;
 693         }
 694
 695 out:
 696         if (fn)
 697                 fn(data, err);
 698         return 0;
 699 }
 700
 701 /*
 702  * alua_prep_fn - request callback
 703  *
 704  * Fail I/O to all paths not in state
 705  * active/optimized or active/non-optimized.
 706  */
 707 static int alua_prep_fn(struct scsi_device *sdev, struct request *req)
 708 {
 709         struct alua_dh_data *h = get_alua_data(sdev);
 710         int ret = BLKPREP_OK;
 711
 712         if (h->state == TPGS_STATE_TRANSITIONING)
 713                 ret = BLKPREP_DEFER;
 714         else if (h->state != TPGS_STATE_OPTIMIZED &&
 715                  h->state != TPGS_STATE_NONOPTIMIZED &&
 716                  h->state != TPGS_STATE_LBA_DEPENDENT) {
 717                 ret = BLKPREP_KILL;
 718                 req->cmd_flags |= REQ_QUIET;
 719         }
 720         return ret;
 721
 722 }
 723
 724 static const struct scsi_dh_devlist alua_dev_list[] = {
 725         {"HP", "MSA VOLUME" },
 726         {"HP", "HSV101" },
 727         {"HP", "HSV111" },
 728         {"HP", "HSV200" },
 729         {"HP", "HSV210" },
 730         {"HP", "HSV300" },
 731         {"IBM", "2107900" },
 732         {"IBM", "2145" },
 733         {"Pillar", "Axiom" },
 734         {"Intel", "Multi-Flex"},
 735         {"NETAPP", "LUN"},
 736         {"NETAPP", "LUN C-Mode"},
 737         {"AIX", "NVDISK"},
 738         {"Promise", "VTrak"},
 739         {NULL, NULL}
 740 };
 741
 742 static int alua_bus_attach(struct scsi_device *sdev);
 743 static void alua_bus_detach(struct scsi_device *sdev);
 744
 745 static struct scsi_device_handler alua_dh = {
 746         .name = ALUA_DH_NAME,
 747         .module = THIS_MODULE,
 748         .devlist = alua_dev_list,
 749         .attach = alua_bus_attach,
 750         .detach = alua_bus_detach,
 751         .prep_fn = alua_prep_fn,
 752         .check_sense = alua_check_sense,
 753         .activate = alua_activate,
 754 };
 755
 756 /*
 757  * alua_bus_attach - Attach device handler
 758  * @sdev: device to be attached to
 759  */
 760 static int alua_bus_attach(struct scsi_device *sdev)
 761 {
 762         struct scsi_dh_data *scsi_dh_data;
 763         struct alua_dh_data *h;
 764         unsigned long flags;
 765         int err = SCSI_DH_OK;
 766
 767         scsi_dh_data = kzalloc(sizeof(*scsi_dh_data)
 768                                + sizeof(*h) , GFP_KERNEL);
 769         if (!scsi_dh_data) {
 770                 sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n",
 771                             ALUA_DH_NAME);
 772                 return -ENOMEM;
 773         }
 774
 775         scsi_dh_data->scsi_dh = &alua_dh;
 776         h = (struct alua_dh_data *) scsi_dh_data->buf;
 777         h->tpgs = TPGS_MODE_UNINITIALIZED;
 778         h->state = TPGS_STATE_OPTIMIZED;
 779         h->group_id = -1;
 780         h->rel_port = -1;
 781         h->buff = h->inq;
 782         h->bufflen = ALUA_INQUIRY_SIZE;
 783         h->sdev = sdev;
 784
 785         err = alua_initialize(sdev, h);
 786         if ((err != SCSI_DH_OK) && (err != SCSI_DH_DEV_OFFLINED))
 787                 goto failed;
 788
 789         if (!try_module_get(THIS_MODULE))
 790                 goto failed;
 791
 792         spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
 793         sdev->scsi_dh_data = scsi_dh_data;
 794         spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
 795
 796         return 0;
 797
 798 failed:
 799         kfree(scsi_dh_data);
 800         sdev_printk(KERN_ERR, sdev, "%s: not attached\n", ALUA_DH_NAME);
 801         return -EINVAL;
 802 }
 803
 804 /*
 805  * alua_bus_detach - Detach device handler
 806  * @sdev: device to be detached from
 807  */
 808 static void alua_bus_detach(struct scsi_device *sdev)
 809 {
 810         struct scsi_dh_data *scsi_dh_data;
 811         struct alua_dh_data *h;
 812         unsigned long flags;
 813
 814         spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
 815         scsi_dh_data = sdev->scsi_dh_data;
 816         sdev->scsi_dh_data = NULL;
 817         spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
 818
 819         h = (struct alua_dh_data *) scsi_dh_data->buf;
 820         if (h->buff && h->inq != h->buff)
 821                 kfree(h->buff);
 822         kfree(scsi_dh_data);
 823         module_put(THIS_MODULE);
 824         sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", ALUA_DH_NAME);
 825 }
 826
 827 static int __init alua_init(void)
 828 {
 829         int r;
 830
 831         r = scsi_register_device_handler(&alua_dh);
 832         if (r != 0)
 833                 printk(KERN_ERR "%s: Failed to register scsi device handler",
 834                         ALUA_DH_NAME);
 835         return r;
 836 }
 837
 838 static void __exit alua_exit(void)
 839 {
 840         scsi_unregister_device_handler(&alua_dh);
 841 }
 842
 843 module_init(alua_init);
 844 module_exit(alua_exit);
 845
 846 MODULE_DESCRIPTION("DM Multipath ALUA support");
 847 MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>");
 848 MODULE_LICENSE("GPL");
 849 MODULE_VERSION(ALUA_DH_VER);