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_OK;
 257
 258         if (error || host_byte(req->errors) != DID_OK ||
 259                         msg_byte(req->errors) != COMMAND_COMPLETE) {
 260                 err = SCSI_DH_IO;
 261                 goto done;
 262         }
 263
 264         if (h->senselen > 0) {
 265                 err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
 266                                            &sense_hdr);
 267                 if (!err) {
 268                         err = SCSI_DH_IO;
 269                         goto done;
 270                 }
 271                 err = alua_check_sense(h->sdev, &sense_hdr);
 272                 if (err == ADD_TO_MLQUEUE) {
 273                         err = SCSI_DH_RETRY;
 274                         goto done;
 275                 }
 276                 sdev_printk(KERN_INFO, h->sdev,
 277                             "%s: stpg sense code: %02x/%02x/%02x\n",
 278                             ALUA_DH_NAME, sense_hdr.sense_key,
 279                             sense_hdr.asc, sense_hdr.ascq);
 280                 err = SCSI_DH_IO;
 281         }
 282         if (err == SCSI_DH_OK) {
 283                 h->state = TPGS_STATE_OPTIMIZED;
 284                 sdev_printk(KERN_INFO, h->sdev,
 285                             "%s: port group %02x switched to state %c\n",
 286                             ALUA_DH_NAME, h->group_id,
 287                             print_alua_state(h->state));
 288         }
 289 done:
 290         req->end_io_data = NULL;
 291         __blk_put_request(req->q, req);
 292         if (h->callback_fn) {
 293                 h->callback_fn(h->callback_data, err);
 294                 h->callback_fn = h->callback_data = NULL;
 295         }
 296         return;
 297 }
 298
 299 /*
 300  * submit_stpg - Issue a SET TARGET GROUP STATES command
 301  *
 302  * Currently we're only setting the current target port group state
 303  * to 'active/optimized' and let the array firmware figure out
 304  * the states of the remaining groups.
 305  */
 306 static unsigned submit_stpg(struct alua_dh_data *h)
 307 {
 308         struct request *rq;
 309         int stpg_len = 8;
 310         struct scsi_device *sdev = h->sdev;
 311
 312         /* Prepare the data buffer */
 313         memset(h->buff, 0, stpg_len);
 314         h->buff[4] = TPGS_STATE_OPTIMIZED & 0x0f;
 315         h->buff[6] = (h->group_id >> 8) & 0xff;
 316         h->buff[7] = h->group_id & 0xff;
 317
 318         rq = get_alua_req(sdev, h->buff, stpg_len, WRITE);
 319         if (!rq)
 320                 return SCSI_DH_RES_TEMP_UNAVAIL;
 321
 322         /* Prepare the command. */
 323         rq->cmd[0] = MAINTENANCE_OUT;
 324         rq->cmd[1] = MO_SET_TARGET_PGS;
 325         rq->cmd[6] = (stpg_len >> 24) & 0xff;
 326         rq->cmd[7] = (stpg_len >> 16) & 0xff;
 327         rq->cmd[8] = (stpg_len >>  8) & 0xff;
 328         rq->cmd[9] = stpg_len & 0xff;
 329         rq->cmd_len = COMMAND_SIZE(MAINTENANCE_OUT);
 330
 331         rq->sense = h->sense;
 332         memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
 333         rq->sense_len = h->senselen = 0;
 334         rq->end_io_data = h;
 335
 336         blk_execute_rq_nowait(rq->q, NULL, rq, 1, stpg_endio);
 337         return SCSI_DH_OK;
 338 }
 339
 340 /*
 341  * alua_std_inquiry - Evaluate standard INQUIRY command
 342  * @sdev: device to be checked
 343  *
 344  * Just extract the TPGS setting to find out if ALUA
 345  * is supported.
 346  */
 347 static int alua_std_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 348 {
 349         int err;
 350
 351         err = submit_std_inquiry(sdev, h);
 352
 353         if (err != SCSI_DH_OK)
 354                 return err;
 355
 356         /* Check TPGS setting */
 357         h->tpgs = (h->inq[5] >> 4) & 0x3;
 358         switch (h->tpgs) {
 359         case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT:
 360                 sdev_printk(KERN_INFO, sdev,
 361                             "%s: supports implicit and explicit TPGS\n",
 362                             ALUA_DH_NAME);
 363                 break;
 364         case TPGS_MODE_EXPLICIT:
 365                 sdev_printk(KERN_INFO, sdev, "%s: supports explicit TPGS\n",
 366                             ALUA_DH_NAME);
 367                 break;
 368         case TPGS_MODE_IMPLICIT:
 369                 sdev_printk(KERN_INFO, sdev, "%s: supports implicit TPGS\n",
 370                             ALUA_DH_NAME);
 371                 break;
 372         default:
 373                 h->tpgs = TPGS_MODE_NONE;
 374                 sdev_printk(KERN_INFO, sdev, "%s: not supported\n",
 375                             ALUA_DH_NAME);
 376                 err = SCSI_DH_DEV_UNSUPP;
 377                 break;
 378         }
 379
 380         return err;
 381 }
 382
 383 /*
 384  * alua_vpd_inquiry - Evaluate INQUIRY vpd page 0x83
 385  * @sdev: device to be checked
 386  *
 387  * Extract the relative target port and the target port group
 388  * descriptor from the list of identificators.
 389  */
 390 static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 391 {
 392         int len;
 393         unsigned err;
 394         unsigned char *d;
 395
 396  retry:
 397         err = submit_vpd_inquiry(sdev, h);
 398
 399         if (err != SCSI_DH_OK)
 400                 return err;
 401
 402         /* Check if vpd page exceeds initial buffer */
 403         len = (h->buff[2] << 8) + h->buff[3] + 4;
 404         if (len > h->bufflen) {
 405                 /* Resubmit with the correct length */
 406                 if (realloc_buffer(h, len)) {
 407                         sdev_printk(KERN_WARNING, sdev,
 408                                     "%s: kmalloc buffer failed\n",
 409                                     ALUA_DH_NAME);
 410                         /* Temporary failure, bypass */
 411                         return SCSI_DH_DEV_TEMP_BUSY;
 412                 }
 413                 goto retry;
 414         }
 415
 416         /*
 417          * Now look for the correct descriptor.
 418          */
 419         d = h->buff + 4;
 420         while (d < h->buff + len) {
 421                 switch (d[1] & 0xf) {
 422                 case 0x4:
 423                         /* Relative target port */
 424                         h->rel_port = (d[6] << 8) + d[7];
 425                         break;
 426                 case 0x5:
 427                         /* Target port group */
 428                         h->group_id = (d[6] << 8) + d[7];
 429                         break;
 430                 default:
 431                         break;
 432                 }
 433                 d += d[3] + 4;
 434         }
 435
 436         if (h->group_id == -1) {
 437                 /*
 438                  * Internal error; TPGS supported but required
 439                  * VPD identification descriptors not present.
 440                  * Disable ALUA support
 441                  */
 442                 sdev_printk(KERN_INFO, sdev,
 443                             "%s: No target port descriptors found\n",
 444                             ALUA_DH_NAME);
 445                 h->state = TPGS_STATE_OPTIMIZED;
 446                 h->tpgs = TPGS_MODE_NONE;
 447                 err = SCSI_DH_DEV_UNSUPP;
 448         } else {
 449                 sdev_printk(KERN_INFO, sdev,
 450                             "%s: port group %02x rel port %02x\n",
 451                             ALUA_DH_NAME, h->group_id, h->rel_port);
 452         }
 453
 454         return err;
 455 }
 456
 457 static char print_alua_state(int state)
 458 {
 459         switch (state) {
 460         case TPGS_STATE_OPTIMIZED:
 461                 return 'A';
 462         case TPGS_STATE_NONOPTIMIZED:
 463                 return 'N';
 464         case TPGS_STATE_STANDBY:
 465                 return 'S';
 466         case TPGS_STATE_UNAVAILABLE:
 467                 return 'U';
 468         case TPGS_STATE_LBA_DEPENDENT:
 469                 return 'L';
 470         case TPGS_STATE_OFFLINE:
 471                 return 'O';
 472         case TPGS_STATE_TRANSITIONING:
 473                 return 'T';
 474         default:
 475                 return 'X';
 476         }
 477 }
 478
 479 static int alua_check_sense(struct scsi_device *sdev,
 480                             struct scsi_sense_hdr *sense_hdr)
 481 {
 482         switch (sense_hdr->sense_key) {
 483         case NOT_READY:
 484                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a)
 485                         /*
 486                          * LUN Not Accessible - ALUA state transition
 487                          */
 488                         return ADD_TO_MLQUEUE;
 489                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0b)
 490                         /*
 491                          * LUN Not Accessible -- Target port in standby state
 492                          */
 493                         return SUCCESS;
 494                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0c)
 495                         /*
 496                          * LUN Not Accessible -- Target port in unavailable state
 497                          */
 498                         return SUCCESS;
 499                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x12)
 500                         /*
 501                          * LUN Not Ready -- Offline
 502                          */
 503                         return SUCCESS;
 504                 break;
 505         case UNIT_ATTENTION:
 506                 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
 507                         /*
 508                          * Power On, Reset, or Bus Device Reset, just retry.
 509                          */
 510                         return ADD_TO_MLQUEUE;
 511                 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) {
 512                         /*
 513                          * ALUA state changed
 514                          */
 515                         return ADD_TO_MLQUEUE;
 516                 }
 517                 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) {
 518                         /*
 519                          * Implicit ALUA state transition failed
 520                          */
 521                         return ADD_TO_MLQUEUE;
 522                 }
 523                 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x0e) {
 524                         /*
 525                          * REPORTED_LUNS_DATA_HAS_CHANGED is reported
 526                          * when switching controllers on targets like
 527                          * Intel Multi-Flex. We can just retry.
 528                          */
 529                         return ADD_TO_MLQUEUE;
 530                 }
 531
 532                 break;
 533         }
 534
 535         return SCSI_RETURN_NOT_HANDLED;
 536 }
 537
 538 /*
 539  * alua_rtpg - Evaluate REPORT TARGET GROUP STATES
 540  * @sdev: the device to be evaluated.
 541  *
 542  * Evaluate the Target Port Group State.
 543  * Returns SCSI_DH_DEV_OFFLINED if the path is
 544  * found to be unusable.
 545  */
 546 static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
 547 {
 548         struct scsi_sense_hdr sense_hdr;
 549         int len, k, off, valid_states = 0;
 550         char *ucp;
 551         unsigned err;
 552         unsigned long expiry, interval = 10;
 553
 554         expiry = round_jiffies_up(jiffies + ALUA_FAILOVER_TIMEOUT);
 555  retry:
 556         err = submit_rtpg(sdev, h);
 557
 558         if (err == SCSI_DH_IO && h->senselen > 0) {
 559                 err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
 560                                            &sense_hdr);
 561                 if (!err)
 562                         return SCSI_DH_IO;
 563
 564                 err = alua_check_sense(sdev, &sense_hdr);
 565                 if (err == ADD_TO_MLQUEUE && time_before(jiffies, expiry))
 566                         goto retry;
 567                 sdev_printk(KERN_INFO, sdev,
 568                             "%s: rtpg sense code %02x/%02x/%02x\n",
 569                             ALUA_DH_NAME, sense_hdr.sense_key,
 570                             sense_hdr.asc, sense_hdr.ascq);
 571                 err = SCSI_DH_IO;
 572         }
 573         if (err != SCSI_DH_OK)
 574                 return err;
 575
 576         len = (h->buff[0] << 24) + (h->buff[1] << 16) +
 577                 (h->buff[2] << 8) + h->buff[3] + 4;
 578
 579         if (len > h->bufflen) {
 580                 /* Resubmit with the correct length */
 581                 if (realloc_buffer(h, len)) {
 582                         sdev_printk(KERN_WARNING, sdev,
 583                                     "%s: kmalloc buffer failed\n",__func__);
 584                         /* Temporary failure, bypass */
 585                         return SCSI_DH_DEV_TEMP_BUSY;
 586                 }
 587                 goto retry;
 588         }
 589
 590         for (k = 4, ucp = h->buff + 4; k < len; k += off, ucp += off) {
 591                 if (h->group_id == (ucp[2] << 8) + ucp[3]) {
 592                         h->state = ucp[0] & 0x0f;
 593                         valid_states = ucp[1];
 594                 }
 595                 off = 8 + (ucp[7] * 4);
 596         }
 597
 598         sdev_printk(KERN_INFO, sdev,
 599                     "%s: port group %02x state %c supports %c%c%c%c%c%c%c\n",
 600                     ALUA_DH_NAME, h->group_id, print_alua_state(h->state),
 601                     valid_states&TPGS_SUPPORT_TRANSITION?'T':'t',
 602                     valid_states&TPGS_SUPPORT_OFFLINE?'O':'o',
 603                     valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l',
 604                     valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u',
 605                     valid_states&TPGS_SUPPORT_STANDBY?'S':'s',
 606                     valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n',
 607                     valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a');
 608
 609         switch (h->state) {
 610         case TPGS_STATE_TRANSITIONING:
 611                 if (time_before(jiffies, expiry)) {
 612                         /* State transition, retry */
 613                         interval *= 10;
 614                         msleep(interval);
 615                         goto retry;
 616                 }
 617                 /* Transitioning time exceeded, set port to standby */
 618                 err = SCSI_DH_RETRY;
 619                 h->state = TPGS_STATE_STANDBY;
 620                 break;
 621         case TPGS_STATE_OFFLINE:
 622         case TPGS_STATE_UNAVAILABLE:
 623                 /* Path unusable for unavailable/offline */
 624                 err = SCSI_DH_DEV_OFFLINED;
 625                 break;
 626         default:
 627                 /* Useable path if active */
 628                 err = SCSI_DH_OK;
 629                 break;
 630         }
 631         return err;
 632 }
 633
 634 /*
 635  * alua_initialize - Initialize ALUA state
 636  * @sdev: the device to be initialized
 637  *
 638  * For the prep_fn to work correctly we have
 639  * to initialize the ALUA state for the device.
 640  */
 641 static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h)
 642 {
 643         int err;
 644
 645         err = alua_std_inquiry(sdev, h);
 646         if (err != SCSI_DH_OK)
 647                 goto out;
 648
 649         err = alua_vpd_inquiry(sdev, h);
 650         if (err != SCSI_DH_OK)
 651                 goto out;
 652
 653         err = alua_rtpg(sdev, h);
 654         if (err != SCSI_DH_OK)
 655                 goto out;
 656
 657 out:
 658         return err;
 659 }
 660
 661 /*
 662  * alua_activate - activate a path
 663  * @sdev: device on the path to be activated
 664  *
 665  * We're currently switching the port group to be activated only and
 666  * let the array figure out the rest.
 667  * There may be other arrays which require us to switch all port groups
 668  * based on a certain policy. But until we actually encounter them it
 669  * should be okay.
 670  */
 671 static int alua_activate(struct scsi_device *sdev,
 672                         activate_complete fn, void *data)
 673 {
 674         struct alua_dh_data *h = get_alua_data(sdev);
 675         int err = SCSI_DH_OK;
 676
 677         if (h->group_id != -1) {
 678                 err = alua_rtpg(sdev, h);
 679                 if (err != SCSI_DH_OK)
 680                         goto out;
 681         }
 682
 683         if (h->tpgs & TPGS_MODE_EXPLICIT &&
 684             h->state != TPGS_STATE_OPTIMIZED &&
 685             h->state != TPGS_STATE_LBA_DEPENDENT) {
 686                 h->callback_fn = fn;
 687                 h->callback_data = data;
 688                 err = submit_stpg(h);
 689                 if (err == SCSI_DH_OK)
 690                         return 0;
 691                 h->callback_fn = h->callback_data = NULL;
 692         }
 693
 694 out:
 695         if (fn)
 696                 fn(data, err);
 697         return 0;
 698 }
 699
 700 /*
 701  * alua_prep_fn - request callback
 702  *
 703  * Fail I/O to all paths not in state
 704  * active/optimized or active/non-optimized.
 705  */
 706 static int alua_prep_fn(struct scsi_device *sdev, struct request *req)
 707 {
 708         struct alua_dh_data *h = get_alua_data(sdev);
 709         int ret = BLKPREP_OK;
 710
 711         if (h->state == TPGS_STATE_TRANSITIONING)
 712                 ret = BLKPREP_DEFER;
 713         else if (h->state != TPGS_STATE_OPTIMIZED &&
 714                  h->state != TPGS_STATE_NONOPTIMIZED &&
 715                  h->state != TPGS_STATE_LBA_DEPENDENT) {
 716                 ret = BLKPREP_KILL;
 717                 req->cmd_flags |= REQ_QUIET;
 718         }
 719         return ret;
 720
 721 }
 722
 723 static const struct scsi_dh_devlist alua_dev_list[] = {
 724         {"HP", "MSA VOLUME" },
 725         {"HP", "HSV101" },
 726         {"HP", "HSV111" },
 727         {"HP", "HSV200" },
 728         {"HP", "HSV210" },
 729         {"HP", "HSV300" },
 730         {"IBM", "2107900" },
 731         {"IBM", "2145" },
 732         {"Pillar", "Axiom" },
 733         {"Intel", "Multi-Flex"},
 734         {"NETAPP", "LUN"},
 735         {"NETAPP", "LUN C-Mode"},
 736         {"AIX", "NVDISK"},
 737         {"Promise", "VTrak"},
 738         {NULL, NULL}
 739 };
 740
 741 static int alua_bus_attach(struct scsi_device *sdev);
 742 static void alua_bus_detach(struct scsi_device *sdev);
 743
 744 static struct scsi_device_handler alua_dh = {
 745         .name = ALUA_DH_NAME,
 746         .module = THIS_MODULE,
 747         .devlist = alua_dev_list,
 748         .attach = alua_bus_attach,
 749         .detach = alua_bus_detach,
 750         .prep_fn = alua_prep_fn,
 751         .check_sense = alua_check_sense,
 752         .activate = alua_activate,
 753 };
 754
 755 /*
 756  * alua_bus_attach - Attach device handler
 757  * @sdev: device to be attached to
 758  */
 759 static int alua_bus_attach(struct scsi_device *sdev)
 760 {
 761         struct scsi_dh_data *scsi_dh_data;
 762         struct alua_dh_data *h;
 763         unsigned long flags;
 764         int err = SCSI_DH_OK;
 765
 766         scsi_dh_data = kzalloc(sizeof(*scsi_dh_data)
 767                                + sizeof(*h) , GFP_KERNEL);
 768         if (!scsi_dh_data) {
 769                 sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n",
 770                             ALUA_DH_NAME);
 771                 return -ENOMEM;
 772         }
 773
 774         scsi_dh_data->scsi_dh = &alua_dh;
 775         h = (struct alua_dh_data *) scsi_dh_data->buf;
 776         h->tpgs = TPGS_MODE_UNINITIALIZED;
 777         h->state = TPGS_STATE_OPTIMIZED;
 778         h->group_id = -1;
 779         h->rel_port = -1;
 780         h->buff = h->inq;
 781         h->bufflen = ALUA_INQUIRY_SIZE;
 782         h->sdev = sdev;
 783
 784         err = alua_initialize(sdev, h);
 785         if ((err != SCSI_DH_OK) && (err != SCSI_DH_DEV_OFFLINED))
 786                 goto failed;
 787
 788         if (!try_module_get(THIS_MODULE))
 789                 goto failed;
 790
 791         spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
 792         sdev->scsi_dh_data = scsi_dh_data;
 793         spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
 794
 795         return 0;
 796
 797 failed:
 798         kfree(scsi_dh_data);
 799         sdev_printk(KERN_ERR, sdev, "%s: not attached\n", ALUA_DH_NAME);
 800         return -EINVAL;
 801 }
 802
 803 /*
 804  * alua_bus_detach - Detach device handler
 805  * @sdev: device to be detached from
 806  */
 807 static void alua_bus_detach(struct scsi_device *sdev)
 808 {
 809         struct scsi_dh_data *scsi_dh_data;
 810         struct alua_dh_data *h;
 811         unsigned long flags;
 812
 813         spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
 814         scsi_dh_data = sdev->scsi_dh_data;
 815         sdev->scsi_dh_data = NULL;
 816         spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
 817
 818         h = (struct alua_dh_data *) scsi_dh_data->buf;
 819         if (h->buff && h->inq != h->buff)
 820                 kfree(h->buff);
 821         kfree(scsi_dh_data);
 822         module_put(THIS_MODULE);
 823         sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", ALUA_DH_NAME);
 824 }
 825
 826 static int __init alua_init(void)
 827 {
 828         int r;
 829
 830         r = scsi_register_device_handler(&alua_dh);
 831         if (r != 0)
 832                 printk(KERN_ERR "%s: Failed to register scsi device handler",
 833                         ALUA_DH_NAME);
 834         return r;
 835 }
 836
 837 static void __exit alua_exit(void)
 838 {
 839         scsi_unregister_device_handler(&alua_dh);
 840 }
 841
 842 module_init(alua_init);
 843 module_exit(alua_exit);
 844
 845 MODULE_DESCRIPTION("DM Multipath ALUA support");
 846 MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>");
 847 MODULE_LICENSE("GPL");
 848 MODULE_VERSION(ALUA_DH_VER);