drivers/scsi/device_handler/scsi_dh_alua.c

   1 /*
   2  * Generic SCSI-3 ALUA SCSI Device Handler
   3  *
   4  * Copyright (C) 2007, 2008 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 <scsi/scsi.h>
  23 #include <scsi/scsi_eh.h>
  24 #include <scsi/scsi_dh.h>
  25
  26 #define ALUA_DH_NAME "alua"
  27 #define ALUA_DH_VER "1.2"
  28
  29 #define TPGS_STATE_OPTIMIZED            0x0
  30 #define TPGS_STATE_NONOPTIMIZED         0x1
  31 #define TPGS_STATE_STANDBY              0x2
  32 #define TPGS_STATE_UNAVAILABLE          0x3
  33 #define TPGS_STATE_OFFLINE              0xe
  34 #define TPGS_STATE_TRANSITIONING        0xf
  35
  36 #define TPGS_SUPPORT_NONE               0x00
  37 #define TPGS_SUPPORT_OPTIMIZED          0x01
  38 #define TPGS_SUPPORT_NONOPTIMIZED       0x02
  39 #define TPGS_SUPPORT_STANDBY            0x04
  40 #define TPGS_SUPPORT_UNAVAILABLE        0x08
  41 #define TPGS_SUPPORT_OFFLINE            0x40
  42 #define TPGS_SUPPORT_TRANSITION         0x80
  43
  44 #define TPGS_MODE_UNINITIALIZED          -1
  45 #define TPGS_MODE_NONE                  0x0
  46 #define TPGS_MODE_IMPLICIT              0x1
  47 #define TPGS_MODE_EXPLICIT              0x2
  48
  49 #define ALUA_INQUIRY_SIZE               36
  50 #define ALUA_FAILOVER_TIMEOUT           (60 * HZ)
  51 #define ALUA_FAILOVER_RETRIES           5
  52
  53 struct alua_dh_data {
  54         int                     group_id;
  55         int                     rel_port;
  56         int                     tpgs;
  57         int                     state;
  58         unsigned char           inq[ALUA_INQUIRY_SIZE];
  59         unsigned char           *buff;
  60         int                     bufflen;
  61         unsigned char           sense[SCSI_SENSE_BUFFERSIZE];
  62         int                     senselen;
  63 };
  64
  65 #define ALUA_POLICY_SWITCH_CURRENT      0
  66 #define ALUA_POLICY_SWITCH_ALL          1
  67
  68 static inline struct alua_dh_data *get_alua_data(struct scsi_device *sdev)
  69 {
  70         struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
  71         BUG_ON(scsi_dh_data == NULL);
  72         return ((struct alua_dh_data *) scsi_dh_data->buf);
  73 }
  74
  75 static int realloc_buffer(struct alua_dh_data *h, unsigned len)
  76 {
  77         if (h->buff && h->buff != h->inq)
  78                 kfree(h->buff);
  79
  80         h->buff = kmalloc(len, GFP_NOIO);
  81         if (!h->buff) {
  82                 h->buff = h->inq;
  83                 h->bufflen = ALUA_INQUIRY_SIZE;
  84                 return 1;
  85         }
  86         h->bufflen = len;
  87         return 0;
  88 }
  89
  90 static struct request *get_alua_req(struct scsi_device *sdev,
  91                                     void *buffer, unsigned buflen, int rw)
  92 {
  93         struct request *rq;
  94         struct request_queue *q = sdev->request_queue;
  95
  96         rq = blk_get_request(q, rw, GFP_NOIO);
  97
  98         if (!rq) {
  99                 sdev_printk(KERN_INFO, sdev,
 100                             "%s: blk_get_request failed\n", __func__);
 101                 return NULL;
 102         }
 103
 104         if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_NOIO)) {
 105                 blk_put_request(rq);
 106                 sdev_printk(KERN_INFO, sdev,
 107                             "%s: blk_rq_map_kern failed\n", __func__);
 108                 return NULL;
 109         }
 110
 111         rq->cmd_type = REQ_TYPE_BLOCK_PC;
 112         rq->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
 113                          REQ_FAILFAST_DRIVER | REQ_NOMERGE;
 114         rq->retries = ALUA_FAILOVER_RETRIES;
 115         rq->timeout = ALUA_FAILOVER_TIMEOUT;
 116
 117         return rq;
 118 }
 119
 120 /*
 121  * submit_std_inquiry - Issue a standard INQUIRY command
 122  * @sdev: sdev the command should be send to
 123  */
 124 static int submit_std_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 125 {
 126         struct request *rq;
 127         int err = SCSI_DH_RES_TEMP_UNAVAIL;
 128
 129         rq = get_alua_req(sdev, h->inq, ALUA_INQUIRY_SIZE, READ);
 130         if (!rq)
 131                 goto done;
 132
 133         /* Prepare the command. */
 134         rq->cmd[0] = INQUIRY;
 135         rq->cmd[1] = 0;
 136         rq->cmd[2] = 0;
 137         rq->cmd[4] = ALUA_INQUIRY_SIZE;
 138         rq->cmd_len = COMMAND_SIZE(INQUIRY);
 139
 140         rq->sense = h->sense;
 141         memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
 142         rq->sense_len = h->senselen = 0;
 143
 144         err = blk_execute_rq(rq->q, NULL, rq, 1);
 145         if (err == -EIO) {
 146                 sdev_printk(KERN_INFO, sdev,
 147                             "%s: std inquiry failed with %x\n",
 148                             ALUA_DH_NAME, rq->errors);
 149                 h->senselen = rq->sense_len;
 150                 err = SCSI_DH_IO;
 151         }
 152         blk_put_request(rq);
 153 done:
 154         return err;
 155 }
 156
 157 /*
 158  * submit_vpd_inquiry - Issue an INQUIRY VPD page 0x83 command
 159  * @sdev: sdev the command should be sent to
 160  */
 161 static int submit_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 162 {
 163         struct request *rq;
 164         int err = SCSI_DH_RES_TEMP_UNAVAIL;
 165
 166         rq = get_alua_req(sdev, h->buff, h->bufflen, READ);
 167         if (!rq)
 168                 goto done;
 169
 170         /* Prepare the command. */
 171         rq->cmd[0] = INQUIRY;
 172         rq->cmd[1] = 1;
 173         rq->cmd[2] = 0x83;
 174         rq->cmd[4] = h->bufflen;
 175         rq->cmd_len = COMMAND_SIZE(INQUIRY);
 176
 177         rq->sense = h->sense;
 178         memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
 179         rq->sense_len = h->senselen = 0;
 180
 181         err = blk_execute_rq(rq->q, NULL, rq, 1);
 182         if (err == -EIO) {
 183                 sdev_printk(KERN_INFO, sdev,
 184                             "%s: evpd inquiry failed with %x\n",
 185                             ALUA_DH_NAME, rq->errors);
 186                 h->senselen = rq->sense_len;
 187                 err = SCSI_DH_IO;
 188         }
 189         blk_put_request(rq);
 190 done:
 191         return err;
 192 }
 193
 194 /*
 195  * submit_rtpg - Issue a REPORT TARGET GROUP STATES command
 196  * @sdev: sdev the command should be sent to
 197  */
 198 static unsigned submit_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
 199 {
 200         struct request *rq;
 201         int err = SCSI_DH_RES_TEMP_UNAVAIL;
 202
 203         rq = get_alua_req(sdev, h->buff, h->bufflen, READ);
 204         if (!rq)
 205                 goto done;
 206
 207         /* Prepare the command. */
 208         rq->cmd[0] = MAINTENANCE_IN;
 209         rq->cmd[1] = MI_REPORT_TARGET_PGS;
 210         rq->cmd[6] = (h->bufflen >> 24) & 0xff;
 211         rq->cmd[7] = (h->bufflen >> 16) & 0xff;
 212         rq->cmd[8] = (h->bufflen >>  8) & 0xff;
 213         rq->cmd[9] = h->bufflen & 0xff;
 214         rq->cmd_len = COMMAND_SIZE(MAINTENANCE_IN);
 215
 216         rq->sense = h->sense;
 217         memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
 218         rq->sense_len = h->senselen = 0;
 219
 220         err = blk_execute_rq(rq->q, NULL, rq, 1);
 221         if (err == -EIO) {
 222                 sdev_printk(KERN_INFO, sdev,
 223                             "%s: rtpg failed with %x\n",
 224                             ALUA_DH_NAME, rq->errors);
 225                 h->senselen = rq->sense_len;
 226                 err = SCSI_DH_IO;
 227         }
 228         blk_put_request(rq);
 229 done:
 230         return err;
 231 }
 232
 233 /*
 234  * submit_stpg - Issue a SET TARGET GROUP STATES command
 235  * @sdev: sdev the command should be sent to
 236  *
 237  * Currently we're only setting the current target port group state
 238  * to 'active/optimized' and let the array firmware figure out
 239  * the states of the remaining groups.
 240  */
 241 static unsigned submit_stpg(struct scsi_device *sdev, struct alua_dh_data *h)
 242 {
 243         struct request *rq;
 244         int err = SCSI_DH_RES_TEMP_UNAVAIL;
 245         int stpg_len = 8;
 246
 247         /* Prepare the data buffer */
 248         memset(h->buff, 0, stpg_len);
 249         h->buff[4] = TPGS_STATE_OPTIMIZED & 0x0f;
 250         h->buff[6] = (h->group_id >> 8) & 0x0f;
 251         h->buff[7] = h->group_id & 0x0f;
 252
 253         rq = get_alua_req(sdev, h->buff, stpg_len, WRITE);
 254         if (!rq)
 255                 goto done;
 256
 257         /* Prepare the command. */
 258         rq->cmd[0] = MAINTENANCE_OUT;
 259         rq->cmd[1] = MO_SET_TARGET_PGS;
 260         rq->cmd[6] = (stpg_len >> 24) & 0xff;
 261         rq->cmd[7] = (stpg_len >> 16) & 0xff;
 262         rq->cmd[8] = (stpg_len >>  8) & 0xff;
 263         rq->cmd[9] = stpg_len & 0xff;
 264         rq->cmd_len = COMMAND_SIZE(MAINTENANCE_OUT);
 265
 266         rq->sense = h->sense;
 267         memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
 268         rq->sense_len = h->senselen = 0;
 269
 270         err = blk_execute_rq(rq->q, NULL, rq, 1);
 271         if (err == -EIO) {
 272                 sdev_printk(KERN_INFO, sdev,
 273                             "%s: stpg failed with %x\n",
 274                             ALUA_DH_NAME, rq->errors);
 275                 h->senselen = rq->sense_len;
 276                 err = SCSI_DH_IO;
 277         }
 278         blk_put_request(rq);
 279 done:
 280         return err;
 281 }
 282
 283 /*
 284  * alua_std_inquiry - Evaluate standard INQUIRY command
 285  * @sdev: device to be checked
 286  *
 287  * Just extract the TPGS setting to find out if ALUA
 288  * is supported.
 289  */
 290 static int alua_std_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 291 {
 292         int err;
 293
 294         err = submit_std_inquiry(sdev, h);
 295
 296         if (err != SCSI_DH_OK)
 297                 return err;
 298
 299         /* Check TPGS setting */
 300         h->tpgs = (h->inq[5] >> 4) & 0x3;
 301         switch (h->tpgs) {
 302         case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT:
 303                 sdev_printk(KERN_INFO, sdev,
 304                             "%s: supports implicit and explicit TPGS\n",
 305                             ALUA_DH_NAME);
 306                 break;
 307         case TPGS_MODE_EXPLICIT:
 308                 sdev_printk(KERN_INFO, sdev, "%s: supports explicit TPGS\n",
 309                             ALUA_DH_NAME);
 310                 break;
 311         case TPGS_MODE_IMPLICIT:
 312                 sdev_printk(KERN_INFO, sdev, "%s: supports implicit TPGS\n",
 313                             ALUA_DH_NAME);
 314                 break;
 315         default:
 316                 h->tpgs = TPGS_MODE_NONE;
 317                 sdev_printk(KERN_INFO, sdev, "%s: not supported\n",
 318                             ALUA_DH_NAME);
 319                 err = SCSI_DH_DEV_UNSUPP;
 320                 break;
 321         }
 322
 323         return err;
 324 }
 325
 326 /*
 327  * alua_vpd_inquiry - Evaluate INQUIRY vpd page 0x83
 328  * @sdev: device to be checked
 329  *
 330  * Extract the relative target port and the target port group
 331  * descriptor from the list of identificators.
 332  */
 333 static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 334 {
 335         int len;
 336         unsigned err;
 337         unsigned char *d;
 338
 339  retry:
 340         err = submit_vpd_inquiry(sdev, h);
 341
 342         if (err != SCSI_DH_OK)
 343                 return err;
 344
 345         /* Check if vpd page exceeds initial buffer */
 346         len = (h->buff[2] << 8) + h->buff[3] + 4;
 347         if (len > h->bufflen) {
 348                 /* Resubmit with the correct length */
 349                 if (realloc_buffer(h, len)) {
 350                         sdev_printk(KERN_WARNING, sdev,
 351                                     "%s: kmalloc buffer failed\n",
 352                                     ALUA_DH_NAME);
 353                         /* Temporary failure, bypass */
 354                         return SCSI_DH_DEV_TEMP_BUSY;
 355                 }
 356                 goto retry;
 357         }
 358
 359         /*
 360          * Now look for the correct descriptor.
 361          */
 362         d = h->buff + 4;
 363         while (d < h->buff + len) {
 364                 switch (d[1] & 0xf) {
 365                 case 0x4:
 366                         /* Relative target port */
 367                         h->rel_port = (d[6] << 8) + d[7];
 368                         break;
 369                 case 0x5:
 370                         /* Target port group */
 371                         h->group_id = (d[6] << 8) + d[7];
 372                         break;
 373                 default:
 374                         break;
 375                 }
 376                 d += d[3] + 4;
 377         }
 378
 379         if (h->group_id == -1) {
 380                 /*
 381                  * Internal error; TPGS supported but required
 382                  * VPD identification descriptors not present.
 383                  * Disable ALUA support
 384                  */
 385                 sdev_printk(KERN_INFO, sdev,
 386                             "%s: No target port descriptors found\n",
 387                             ALUA_DH_NAME);
 388                 h->state = TPGS_STATE_OPTIMIZED;
 389                 h->tpgs = TPGS_MODE_NONE;
 390                 err = SCSI_DH_DEV_UNSUPP;
 391         } else {
 392                 sdev_printk(KERN_INFO, sdev,
 393                             "%s: port group %02x rel port %02x\n",
 394                             ALUA_DH_NAME, h->group_id, h->rel_port);
 395         }
 396
 397         return err;
 398 }
 399
 400 static char print_alua_state(int state)
 401 {
 402         switch (state) {
 403         case TPGS_STATE_OPTIMIZED:
 404                 return 'A';
 405         case TPGS_STATE_NONOPTIMIZED:
 406                 return 'N';
 407         case TPGS_STATE_STANDBY:
 408                 return 'S';
 409         case TPGS_STATE_UNAVAILABLE:
 410                 return 'U';
 411         case TPGS_STATE_OFFLINE:
 412                 return 'O';
 413         case TPGS_STATE_TRANSITIONING:
 414                 return 'T';
 415         default:
 416                 return 'X';
 417         }
 418 }
 419
 420 static int alua_check_sense(struct scsi_device *sdev,
 421                             struct scsi_sense_hdr *sense_hdr)
 422 {
 423         switch (sense_hdr->sense_key) {
 424         case NOT_READY:
 425                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a)
 426                         /*
 427                          * LUN Not Accessible - ALUA state transition
 428                          */
 429                         return ADD_TO_MLQUEUE;
 430                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0b)
 431                         /*
 432                          * LUN Not Accessible -- Target port in standby state
 433                          */
 434                         return SUCCESS;
 435                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0c)
 436                         /*
 437                          * LUN Not Accessible -- Target port in unavailable state
 438                          */
 439                         return SUCCESS;
 440                 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x12)
 441                         /*
 442                          * LUN Not Ready -- Offline
 443                          */
 444                         return SUCCESS;
 445                 break;
 446         case UNIT_ATTENTION:
 447                 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
 448                         /*
 449                          * Power On, Reset, or Bus Device Reset, just retry.
 450                          */
 451                         return ADD_TO_MLQUEUE;
 452                 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) {
 453                         /*
 454                          * ALUA state changed
 455                          */
 456                         return ADD_TO_MLQUEUE;
 457                 }
 458                 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) {
 459                         /*
 460                          * Implicit ALUA state transition failed
 461                          */
 462                         return ADD_TO_MLQUEUE;
 463                 }
 464                 break;
 465         }
 466
 467         return SCSI_RETURN_NOT_HANDLED;
 468 }
 469
 470 /*
 471  * alua_stpg - Evaluate SET TARGET GROUP STATES
 472  * @sdev: the device to be evaluated
 473  * @state: the new target group state
 474  *
 475  * Send a SET TARGET GROUP STATES command to the device.
 476  * We only have to test here if we should resubmit the command;
 477  * any other error is assumed as a failure.
 478  */
 479 static int alua_stpg(struct scsi_device *sdev, int state,
 480                      struct alua_dh_data *h)
 481 {
 482         struct scsi_sense_hdr sense_hdr;
 483         unsigned err;
 484         int retry = ALUA_FAILOVER_RETRIES;
 485
 486  retry:
 487         err = submit_stpg(sdev, h);
 488         if (err == SCSI_DH_IO && h->senselen > 0) {
 489                 err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
 490                                            &sense_hdr);
 491                 if (!err)
 492                         return SCSI_DH_IO;
 493                 err = alua_check_sense(sdev, &sense_hdr);
 494                 if (retry > 0 && err == ADD_TO_MLQUEUE) {
 495                         retry--;
 496                         goto retry;
 497                 }
 498                 sdev_printk(KERN_INFO, sdev,
 499                             "%s: stpg sense code: %02x/%02x/%02x\n",
 500                             ALUA_DH_NAME, sense_hdr.sense_key,
 501                             sense_hdr.asc, sense_hdr.ascq);
 502                 err = SCSI_DH_IO;
 503         }
 504         if (err == SCSI_DH_OK) {
 505                 h->state = state;
 506                 sdev_printk(KERN_INFO, sdev,
 507                             "%s: port group %02x switched to state %c\n",
 508                             ALUA_DH_NAME, h->group_id,
 509                             print_alua_state(h->state) );
 510         }
 511         return err;
 512 }
 513
 514 /*
 515  * alua_rtpg - Evaluate REPORT TARGET GROUP STATES
 516  * @sdev: the device to be evaluated.
 517  *
 518  * Evaluate the Target Port Group State.
 519  * Returns SCSI_DH_DEV_OFFLINED if the path is
 520  * found to be unuseable.
 521  */
 522 static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
 523 {
 524         struct scsi_sense_hdr sense_hdr;
 525         int len, k, off, valid_states = 0;
 526         char *ucp;
 527         unsigned err;
 528
 529  retry:
 530         err = submit_rtpg(sdev, h);
 531
 532         if (err == SCSI_DH_IO && h->senselen > 0) {
 533                 err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
 534                                            &sense_hdr);
 535                 if (!err)
 536                         return SCSI_DH_IO;
 537
 538                 err = alua_check_sense(sdev, &sense_hdr);
 539                 if (err == ADD_TO_MLQUEUE)
 540                         goto retry;
 541                 sdev_printk(KERN_INFO, sdev,
 542                             "%s: rtpg sense code %02x/%02x/%02x\n",
 543                             ALUA_DH_NAME, sense_hdr.sense_key,
 544                             sense_hdr.asc, sense_hdr.ascq);
 545                 err = SCSI_DH_IO;
 546         }
 547         if (err != SCSI_DH_OK)
 548                 return err;
 549
 550         len = (h->buff[0] << 24) + (h->buff[1] << 16) +
 551                 (h->buff[2] << 8) + h->buff[3] + 4;
 552
 553         if (len > h->bufflen) {
 554                 /* Resubmit with the correct length */
 555                 if (realloc_buffer(h, len)) {
 556                         sdev_printk(KERN_WARNING, sdev,
 557                                     "%s: kmalloc buffer failed\n",__func__);
 558                         /* Temporary failure, bypass */
 559                         return SCSI_DH_DEV_TEMP_BUSY;
 560                 }
 561                 goto retry;
 562         }
 563
 564         for (k = 4, ucp = h->buff + 4; k < len; k += off, ucp += off) {
 565                 if (h->group_id == (ucp[2] << 8) + ucp[3]) {
 566                         h->state = ucp[0] & 0x0f;
 567                         valid_states = ucp[1];
 568                 }
 569                 off = 8 + (ucp[7] * 4);
 570         }
 571
 572         sdev_printk(KERN_INFO, sdev,
 573                     "%s: port group %02x state %c supports %c%c%c%c%c%c\n",
 574                     ALUA_DH_NAME, h->group_id, print_alua_state(h->state),
 575                     valid_states&TPGS_SUPPORT_TRANSITION?'T':'t',
 576                     valid_states&TPGS_SUPPORT_OFFLINE?'O':'o',
 577                     valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u',
 578                     valid_states&TPGS_SUPPORT_STANDBY?'S':'s',
 579                     valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n',
 580                     valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a');
 581
 582         if (h->tpgs & TPGS_MODE_EXPLICIT) {
 583                 switch (h->state) {
 584                 case TPGS_STATE_TRANSITIONING:
 585                         /* State transition, retry */
 586                         goto retry;
 587                         break;
 588                 case TPGS_STATE_OFFLINE:
 589                         /* Path is offline, fail */
 590                         err = SCSI_DH_DEV_OFFLINED;
 591                         break;
 592                 default:
 593                         break;
 594                 }
 595         } else {
 596                 /* Only Implicit ALUA support */
 597                 if (h->state == TPGS_STATE_OPTIMIZED ||
 598                     h->state == TPGS_STATE_NONOPTIMIZED ||
 599                     h->state == TPGS_STATE_STANDBY)
 600                         /* Useable path if active */
 601                         err = SCSI_DH_OK;
 602                 else
 603                         /* Path unuseable for unavailable/offline */
 604                         err = SCSI_DH_DEV_OFFLINED;
 605         }
 606         return err;
 607 }
 608
 609 /*
 610  * alua_initialize - Initialize ALUA state
 611  * @sdev: the device to be initialized
 612  *
 613  * For the prep_fn to work correctly we have
 614  * to initialize the ALUA state for the device.
 615  */
 616 static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h)
 617 {
 618         int err;
 619
 620         err = alua_std_inquiry(sdev, h);
 621         if (err != SCSI_DH_OK)
 622                 goto out;
 623
 624         err = alua_vpd_inquiry(sdev, h);
 625         if (err != SCSI_DH_OK)
 626                 goto out;
 627
 628         err = alua_rtpg(sdev, h);
 629         if (err != SCSI_DH_OK)
 630                 goto out;
 631
 632 out:
 633         return err;
 634 }
 635
 636 /*
 637  * alua_activate - activate a path
 638  * @sdev: device on the path to be activated
 639  *
 640  * We're currently switching the port group to be activated only and
 641  * let the array figure out the rest.
 642  * There may be other arrays which require us to switch all port groups
 643  * based on a certain policy. But until we actually encounter them it
 644  * should be okay.
 645  */
 646 static int alua_activate(struct scsi_device *sdev)
 647 {
 648         struct alua_dh_data *h = get_alua_data(sdev);
 649         int err = SCSI_DH_OK;
 650
 651         if (h->group_id != -1) {
 652                 err = alua_rtpg(sdev, h);
 653                 if (err != SCSI_DH_OK)
 654                         goto out;
 655         }
 656
 657         if (h->tpgs == TPGS_MODE_EXPLICIT && h->state != TPGS_STATE_OPTIMIZED)
 658                 err = alua_stpg(sdev, TPGS_STATE_OPTIMIZED, h);
 659
 660 out:
 661         return err;
 662 }
 663
 664 /*
 665  * alua_prep_fn - request callback
 666  *
 667  * Fail I/O to all paths not in state
 668  * active/optimized or active/non-optimized.
 669  */
 670 static int alua_prep_fn(struct scsi_device *sdev, struct request *req)
 671 {
 672         struct alua_dh_data *h = get_alua_data(sdev);
 673         int ret = BLKPREP_OK;
 674
 675         if (h->state != TPGS_STATE_OPTIMIZED &&
 676             h->state != TPGS_STATE_NONOPTIMIZED) {
 677                 ret = BLKPREP_KILL;
 678                 req->cmd_flags |= REQ_QUIET;
 679         }
 680         return ret;
 681
 682 }
 683
 684 static const struct scsi_dh_devlist alua_dev_list[] = {
 685         {"HP", "MSA VOLUME" },
 686         {"HP", "HSV101" },
 687         {"HP", "HSV111" },
 688         {"HP", "HSV200" },
 689         {"HP", "HSV210" },
 690         {"HP", "HSV300" },
 691         {"IBM", "2107900" },
 692         {"IBM", "2145" },
 693         {"Pillar", "Axiom" },
 694         {NULL, NULL}
 695 };
 696
 697 static int alua_bus_attach(struct scsi_device *sdev);
 698 static void alua_bus_detach(struct scsi_device *sdev);
 699
 700 static struct scsi_device_handler alua_dh = {
 701         .name = ALUA_DH_NAME,
 702         .module = THIS_MODULE,
 703         .devlist = alua_dev_list,
 704         .attach = alua_bus_attach,
 705         .detach = alua_bus_detach,
 706         .prep_fn = alua_prep_fn,
 707         .check_sense = alua_check_sense,
 708         .activate = alua_activate,
 709 };
 710
 711 /*
 712  * alua_bus_attach - Attach device handler
 713  * @sdev: device to be attached to
 714  */
 715 static int alua_bus_attach(struct scsi_device *sdev)
 716 {
 717         struct scsi_dh_data *scsi_dh_data;
 718         struct alua_dh_data *h;
 719         unsigned long flags;
 720         int err = SCSI_DH_OK;
 721
 722         scsi_dh_data = kzalloc(sizeof(struct scsi_device_handler *)
 723                                + sizeof(*h) , GFP_KERNEL);
 724         if (!scsi_dh_data) {
 725                 sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n",
 726                             ALUA_DH_NAME);
 727                 return -ENOMEM;
 728         }
 729
 730         scsi_dh_data->scsi_dh = &alua_dh;
 731         h = (struct alua_dh_data *) scsi_dh_data->buf;
 732         h->tpgs = TPGS_MODE_UNINITIALIZED;
 733         h->state = TPGS_STATE_OPTIMIZED;
 734         h->group_id = -1;
 735         h->rel_port = -1;
 736         h->buff = h->inq;
 737         h->bufflen = ALUA_INQUIRY_SIZE;
 738
 739         err = alua_initialize(sdev, h);
 740         if (err != SCSI_DH_OK)
 741                 goto failed;
 742
 743         if (!try_module_get(THIS_MODULE))
 744                 goto failed;
 745
 746         spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
 747         sdev->scsi_dh_data = scsi_dh_data;
 748         spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
 749
 750         return 0;
 751
 752 failed:
 753         kfree(scsi_dh_data);
 754         sdev_printk(KERN_ERR, sdev, "%s: not attached\n", ALUA_DH_NAME);
 755         return -EINVAL;
 756 }
 757
 758 /*
 759  * alua_bus_detach - Detach device handler
 760  * @sdev: device to be detached from
 761  */
 762 static void alua_bus_detach(struct scsi_device *sdev)
 763 {
 764         struct scsi_dh_data *scsi_dh_data;
 765         struct alua_dh_data *h;
 766         unsigned long flags;
 767
 768         spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
 769         scsi_dh_data = sdev->scsi_dh_data;
 770         sdev->scsi_dh_data = NULL;
 771         spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
 772
 773         h = (struct alua_dh_data *) scsi_dh_data->buf;
 774         if (h->buff && h->inq != h->buff)
 775                 kfree(h->buff);
 776         kfree(scsi_dh_data);
 777         module_put(THIS_MODULE);
 778         sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", ALUA_DH_NAME);
 779 }
 780
 781 static int __init alua_init(void)
 782 {
 783         int r;
 784
 785         r = scsi_register_device_handler(&alua_dh);
 786         if (r != 0)
 787                 printk(KERN_ERR "%s: Failed to register scsi device handler",
 788                         ALUA_DH_NAME);
 789         return r;
 790 }
 791
 792 static void __exit alua_exit(void)
 793 {
 794         scsi_unregister_device_handler(&alua_dh);
 795 }
 796
 797 module_init(alua_init);
 798 module_exit(alua_exit);
 799
 800 MODULE_DESCRIPTION("DM Multipath ALUA support");
 801 MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>");
 802 MODULE_LICENSE("GPL");
 803 MODULE_VERSION(ALUA_DH_VER);