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