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