1 /* 2 * Generic SCSI-3 ALUA SCSI Device Handler 3 * 4 * Copyright (C) 2007-2010 Hannes Reinecke, SUSE Linux Products GmbH. 5 * All rights reserved. 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 20 * 21 */ 22 #include <linux/slab.h> 23 #include <linux/delay.h> 24 #include <linux/module.h> 25 #include <scsi/scsi.h> 26 #include <scsi/scsi_eh.h> 27 #include <scsi/scsi_dh.h> 28 29 #define ALUA_DH_NAME "alua" 30 #define ALUA_DH_VER "1.3" 31 32 #define TPGS_STATE_OPTIMIZED 0x0 33 #define TPGS_STATE_NONOPTIMIZED 0x1 34 #define TPGS_STATE_STANDBY 0x2 35 #define TPGS_STATE_UNAVAILABLE 0x3 36 #define TPGS_STATE_LBA_DEPENDENT 0x4 37 #define TPGS_STATE_OFFLINE 0xe 38 #define TPGS_STATE_TRANSITIONING 0xf 39 40 #define TPGS_SUPPORT_NONE 0x00 41 #define TPGS_SUPPORT_OPTIMIZED 0x01 42 #define TPGS_SUPPORT_NONOPTIMIZED 0x02 43 #define TPGS_SUPPORT_STANDBY 0x04 44 #define TPGS_SUPPORT_UNAVAILABLE 0x08 45 #define TPGS_SUPPORT_LBA_DEPENDENT 0x10 46 #define TPGS_SUPPORT_OFFLINE 0x40 47 #define TPGS_SUPPORT_TRANSITION 0x80 48 49 #define RTPG_FMT_MASK 0x70 50 #define RTPG_FMT_EXT_HDR 0x10 51 52 #define TPGS_MODE_UNINITIALIZED -1 53 #define TPGS_MODE_NONE 0x0 54 #define TPGS_MODE_IMPLICIT 0x1 55 #define TPGS_MODE_EXPLICIT 0x2 56 57 #define ALUA_INQUIRY_SIZE 36 58 #define ALUA_FAILOVER_TIMEOUT 60 59 #define ALUA_FAILOVER_RETRIES 5 60 61 /* flags passed from user level */ 62 #define ALUA_OPTIMIZE_STPG 1 63 64 struct alua_dh_data { 65 int group_id; 66 int rel_port; 67 int tpgs; 68 int state; 69 int pref; 70 unsigned flags; /* used for optimizing STPG */ 71 unsigned char inq[ALUA_INQUIRY_SIZE]; 72 unsigned char *buff; 73 int bufflen; 74 unsigned char transition_tmo; 75 unsigned char sense[SCSI_SENSE_BUFFERSIZE]; 76 int senselen; 77 struct scsi_device *sdev; 78 activate_complete callback_fn; 79 void *callback_data; 80 }; 81 82 #define ALUA_POLICY_SWITCH_CURRENT 0 83 #define ALUA_POLICY_SWITCH_ALL 1 84 85 static char print_alua_state(int); 86 static int alua_check_sense(struct scsi_device *, struct scsi_sense_hdr *); 87 88 static inline struct alua_dh_data *get_alua_data(struct scsi_device *sdev) 89 { 90 struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data; 91 BUG_ON(scsi_dh_data == NULL); 92 return ((struct alua_dh_data *) scsi_dh_data->buf); 93 } 94 95 static int realloc_buffer(struct alua_dh_data *h, unsigned len) 96 { 97 if (h->buff && h->buff != h->inq) 98 kfree(h->buff); 99 100 h->buff = kmalloc(len, GFP_NOIO); 101 if (!h->buff) { 102 h->buff = h->inq; 103 h->bufflen = ALUA_INQUIRY_SIZE; 104 return 1; 105 } 106 h->bufflen = len; 107 return 0; 108 } 109 110 static struct request *get_alua_req(struct scsi_device *sdev, 111 void *buffer, unsigned buflen, int rw) 112 { 113 struct request *rq; 114 struct request_queue *q = sdev->request_queue; 115 116 rq = blk_get_request(q, rw, GFP_NOIO); 117 118 if (!rq) { 119 sdev_printk(KERN_INFO, sdev, 120 "%s: blk_get_request failed\n", __func__); 121 return NULL; 122 } 123 124 if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_NOIO)) { 125 blk_put_request(rq); 126 sdev_printk(KERN_INFO, sdev, 127 "%s: blk_rq_map_kern failed\n", __func__); 128 return NULL; 129 } 130 131 rq->cmd_type = REQ_TYPE_BLOCK_PC; 132 rq->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | 133 REQ_FAILFAST_DRIVER; 134 rq->retries = ALUA_FAILOVER_RETRIES; 135 rq->timeout = ALUA_FAILOVER_TIMEOUT * HZ; 136 137 return rq; 138 } 139 140 /* 141 * submit_vpd_inquiry - Issue an INQUIRY VPD page 0x83 command 142 * @sdev: sdev the command should be sent to 143 */ 144 static int submit_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h) 145 { 146 struct request *rq; 147 int err = SCSI_DH_RES_TEMP_UNAVAIL; 148 149 rq = get_alua_req(sdev, h->buff, h->bufflen, READ); 150 if (!rq) 151 goto done; 152 153 /* Prepare the command. */ 154 rq->cmd[0] = INQUIRY; 155 rq->cmd[1] = 1; 156 rq->cmd[2] = 0x83; 157 rq->cmd[4] = h->bufflen; 158 rq->cmd_len = COMMAND_SIZE(INQUIRY); 159 160 rq->sense = h->sense; 161 memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE); 162 rq->sense_len = h->senselen = 0; 163 164 err = blk_execute_rq(rq->q, NULL, rq, 1); 165 if (err == -EIO) { 166 sdev_printk(KERN_INFO, sdev, 167 "%s: evpd inquiry failed with %x\n", 168 ALUA_DH_NAME, rq->errors); 169 h->senselen = rq->sense_len; 170 err = SCSI_DH_IO; 171 } 172 blk_put_request(rq); 173 done: 174 return err; 175 } 176 177 /* 178 * submit_rtpg - Issue a REPORT TARGET GROUP STATES command 179 * @sdev: sdev the command should be sent to 180 */ 181 static unsigned submit_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, 182 bool rtpg_ext_hdr_req) 183 { 184 struct request *rq; 185 int err = SCSI_DH_RES_TEMP_UNAVAIL; 186 187 rq = get_alua_req(sdev, h->buff, h->bufflen, READ); 188 if (!rq) 189 goto done; 190 191 /* Prepare the command. */ 192 rq->cmd[0] = MAINTENANCE_IN; 193 if (rtpg_ext_hdr_req) 194 rq->cmd[1] = MI_REPORT_TARGET_PGS | MI_EXT_HDR_PARAM_FMT; 195 else 196 rq->cmd[1] = MI_REPORT_TARGET_PGS; 197 rq->cmd[6] = (h->bufflen >> 24) & 0xff; 198 rq->cmd[7] = (h->bufflen >> 16) & 0xff; 199 rq->cmd[8] = (h->bufflen >> 8) & 0xff; 200 rq->cmd[9] = h->bufflen & 0xff; 201 rq->cmd_len = COMMAND_SIZE(MAINTENANCE_IN); 202 203 rq->sense = h->sense; 204 memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE); 205 rq->sense_len = h->senselen = 0; 206 207 err = blk_execute_rq(rq->q, NULL, rq, 1); 208 if (err == -EIO) { 209 sdev_printk(KERN_INFO, sdev, 210 "%s: rtpg failed with %x\n", 211 ALUA_DH_NAME, rq->errors); 212 h->senselen = rq->sense_len; 213 err = SCSI_DH_IO; 214 } 215 blk_put_request(rq); 216 done: 217 return err; 218 } 219 220 /* 221 * alua_stpg - Evaluate SET TARGET GROUP STATES 222 * @sdev: the device to be evaluated 223 * @state: the new target group state 224 * 225 * Send a SET TARGET GROUP STATES command to the device. 226 * We only have to test here if we should resubmit the command; 227 * any other error is assumed as a failure. 228 */ 229 static void stpg_endio(struct request *req, int error) 230 { 231 struct alua_dh_data *h = req->end_io_data; 232 struct scsi_sense_hdr sense_hdr; 233 unsigned err = SCSI_DH_OK; 234 235 if (error || host_byte(req->errors) != DID_OK || 236 msg_byte(req->errors) != COMMAND_COMPLETE) { 237 err = SCSI_DH_IO; 238 goto done; 239 } 240 241 if (h->senselen > 0) { 242 err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE, 243 &sense_hdr); 244 if (!err) { 245 err = SCSI_DH_IO; 246 goto done; 247 } 248 err = alua_check_sense(h->sdev, &sense_hdr); 249 if (err == ADD_TO_MLQUEUE) { 250 err = SCSI_DH_RETRY; 251 goto done; 252 } 253 sdev_printk(KERN_INFO, h->sdev, 254 "%s: stpg sense code: %02x/%02x/%02x\n", 255 ALUA_DH_NAME, sense_hdr.sense_key, 256 sense_hdr.asc, sense_hdr.ascq); 257 err = SCSI_DH_IO; 258 } 259 if (err == SCSI_DH_OK) { 260 h->state = TPGS_STATE_OPTIMIZED; 261 sdev_printk(KERN_INFO, h->sdev, 262 "%s: port group %02x switched to state %c\n", 263 ALUA_DH_NAME, h->group_id, 264 print_alua_state(h->state)); 265 } 266 done: 267 req->end_io_data = NULL; 268 __blk_put_request(req->q, req); 269 if (h->callback_fn) { 270 h->callback_fn(h->callback_data, err); 271 h->callback_fn = h->callback_data = NULL; 272 } 273 return; 274 } 275 276 /* 277 * submit_stpg - Issue a SET TARGET GROUP STATES command 278 * 279 * Currently we're only setting the current target port group state 280 * to 'active/optimized' and let the array firmware figure out 281 * the states of the remaining groups. 282 */ 283 static unsigned submit_stpg(struct alua_dh_data *h) 284 { 285 struct request *rq; 286 int stpg_len = 8; 287 struct scsi_device *sdev = h->sdev; 288 289 /* Prepare the data buffer */ 290 memset(h->buff, 0, stpg_len); 291 h->buff[4] = TPGS_STATE_OPTIMIZED & 0x0f; 292 h->buff[6] = (h->group_id >> 8) & 0xff; 293 h->buff[7] = h->group_id & 0xff; 294 295 rq = get_alua_req(sdev, h->buff, stpg_len, WRITE); 296 if (!rq) 297 return SCSI_DH_RES_TEMP_UNAVAIL; 298 299 /* Prepare the command. */ 300 rq->cmd[0] = MAINTENANCE_OUT; 301 rq->cmd[1] = MO_SET_TARGET_PGS; 302 rq->cmd[6] = (stpg_len >> 24) & 0xff; 303 rq->cmd[7] = (stpg_len >> 16) & 0xff; 304 rq->cmd[8] = (stpg_len >> 8) & 0xff; 305 rq->cmd[9] = stpg_len & 0xff; 306 rq->cmd_len = COMMAND_SIZE(MAINTENANCE_OUT); 307 308 rq->sense = h->sense; 309 memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE); 310 rq->sense_len = h->senselen = 0; 311 rq->end_io_data = h; 312 313 blk_execute_rq_nowait(rq->q, NULL, rq, 1, stpg_endio); 314 return SCSI_DH_OK; 315 } 316 317 /* 318 * alua_check_tpgs - Evaluate TPGS setting 319 * @sdev: device to be checked 320 * 321 * Examine the TPGS setting of the sdev to find out if ALUA 322 * is supported. 323 */ 324 static int alua_check_tpgs(struct scsi_device *sdev, struct alua_dh_data *h) 325 { 326 int err = SCSI_DH_OK; 327 328 h->tpgs = scsi_device_tpgs(sdev); 329 switch (h->tpgs) { 330 case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT: 331 sdev_printk(KERN_INFO, sdev, 332 "%s: supports implicit and explicit TPGS\n", 333 ALUA_DH_NAME); 334 break; 335 case TPGS_MODE_EXPLICIT: 336 sdev_printk(KERN_INFO, sdev, "%s: supports explicit TPGS\n", 337 ALUA_DH_NAME); 338 break; 339 case TPGS_MODE_IMPLICIT: 340 sdev_printk(KERN_INFO, sdev, "%s: supports implicit TPGS\n", 341 ALUA_DH_NAME); 342 break; 343 default: 344 h->tpgs = TPGS_MODE_NONE; 345 sdev_printk(KERN_INFO, sdev, "%s: not supported\n", 346 ALUA_DH_NAME); 347 err = SCSI_DH_DEV_UNSUPP; 348 break; 349 } 350 351 return err; 352 } 353 354 /* 355 * alua_vpd_inquiry - Evaluate INQUIRY vpd page 0x83 356 * @sdev: device to be checked 357 * 358 * Extract the relative target port and the target port group 359 * descriptor from the list of identificators. 360 */ 361 static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h) 362 { 363 int len; 364 unsigned err; 365 unsigned char *d; 366 367 retry: 368 err = submit_vpd_inquiry(sdev, h); 369 370 if (err != SCSI_DH_OK) 371 return err; 372 373 /* Check if vpd page exceeds initial buffer */ 374 len = (h->buff[2] << 8) + h->buff[3] + 4; 375 if (len > h->bufflen) { 376 /* Resubmit with the correct length */ 377 if (realloc_buffer(h, len)) { 378 sdev_printk(KERN_WARNING, sdev, 379 "%s: kmalloc buffer failed\n", 380 ALUA_DH_NAME); 381 /* Temporary failure, bypass */ 382 return SCSI_DH_DEV_TEMP_BUSY; 383 } 384 goto retry; 385 } 386 387 /* 388 * Now look for the correct descriptor. 389 */ 390 d = h->buff + 4; 391 while (d < h->buff + len) { 392 switch (d[1] & 0xf) { 393 case 0x4: 394 /* Relative target port */ 395 h->rel_port = (d[6] << 8) + d[7]; 396 break; 397 case 0x5: 398 /* Target port group */ 399 h->group_id = (d[6] << 8) + d[7]; 400 break; 401 default: 402 break; 403 } 404 d += d[3] + 4; 405 } 406 407 if (h->group_id == -1) { 408 /* 409 * Internal error; TPGS supported but required 410 * VPD identification descriptors not present. 411 * Disable ALUA support 412 */ 413 sdev_printk(KERN_INFO, sdev, 414 "%s: No target port descriptors found\n", 415 ALUA_DH_NAME); 416 h->state = TPGS_STATE_OPTIMIZED; 417 h->tpgs = TPGS_MODE_NONE; 418 err = SCSI_DH_DEV_UNSUPP; 419 } else { 420 sdev_printk(KERN_INFO, sdev, 421 "%s: port group %02x rel port %02x\n", 422 ALUA_DH_NAME, h->group_id, h->rel_port); 423 } 424 425 return err; 426 } 427 428 static char print_alua_state(int state) 429 { 430 switch (state) { 431 case TPGS_STATE_OPTIMIZED: 432 return 'A'; 433 case TPGS_STATE_NONOPTIMIZED: 434 return 'N'; 435 case TPGS_STATE_STANDBY: 436 return 'S'; 437 case TPGS_STATE_UNAVAILABLE: 438 return 'U'; 439 case TPGS_STATE_LBA_DEPENDENT: 440 return 'L'; 441 case TPGS_STATE_OFFLINE: 442 return 'O'; 443 case TPGS_STATE_TRANSITIONING: 444 return 'T'; 445 default: 446 return 'X'; 447 } 448 } 449 450 static int alua_check_sense(struct scsi_device *sdev, 451 struct scsi_sense_hdr *sense_hdr) 452 { 453 switch (sense_hdr->sense_key) { 454 case NOT_READY: 455 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a) 456 /* 457 * LUN Not Accessible - ALUA state transition 458 */ 459 return ADD_TO_MLQUEUE; 460 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0b) 461 /* 462 * LUN Not Accessible -- Target port in standby state 463 */ 464 return SUCCESS; 465 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0c) 466 /* 467 * LUN Not Accessible -- Target port in unavailable state 468 */ 469 return SUCCESS; 470 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x12) 471 /* 472 * LUN Not Ready -- Offline 473 */ 474 return SUCCESS; 475 break; 476 case UNIT_ATTENTION: 477 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00) 478 /* 479 * Power On, Reset, or Bus Device Reset, just retry. 480 */ 481 return ADD_TO_MLQUEUE; 482 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x01) 483 /* 484 * Mode Parameters Changed 485 */ 486 return ADD_TO_MLQUEUE; 487 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) 488 /* 489 * ALUA state changed 490 */ 491 return ADD_TO_MLQUEUE; 492 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) 493 /* 494 * Implicit ALUA state transition failed 495 */ 496 return ADD_TO_MLQUEUE; 497 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x03) 498 /* 499 * Inquiry data has changed 500 */ 501 return ADD_TO_MLQUEUE; 502 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x0e) 503 /* 504 * REPORTED_LUNS_DATA_HAS_CHANGED is reported 505 * when switching controllers on targets like 506 * Intel Multi-Flex. We can just retry. 507 */ 508 return ADD_TO_MLQUEUE; 509 break; 510 } 511 512 return SCSI_RETURN_NOT_HANDLED; 513 } 514 515 /* 516 * alua_rtpg - Evaluate REPORT TARGET GROUP STATES 517 * @sdev: the device to be evaluated. 518 * 519 * Evaluate the Target Port Group State. 520 * Returns SCSI_DH_DEV_OFFLINED if the path is 521 * found to be unusable. 522 */ 523 static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h) 524 { 525 struct scsi_sense_hdr sense_hdr; 526 int len, k, off, valid_states = 0; 527 unsigned char *ucp; 528 unsigned err; 529 bool rtpg_ext_hdr_req = 1; 530 unsigned long expiry, interval = 0; 531 unsigned int tpg_desc_tbl_off; 532 unsigned char orig_transition_tmo; 533 534 if (!h->transition_tmo) 535 expiry = round_jiffies_up(jiffies + ALUA_FAILOVER_TIMEOUT * HZ); 536 else 537 expiry = round_jiffies_up(jiffies + h->transition_tmo * HZ); 538 539 retry: 540 err = submit_rtpg(sdev, h, rtpg_ext_hdr_req); 541 542 if (err == SCSI_DH_IO && h->senselen > 0) { 543 err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE, 544 &sense_hdr); 545 if (!err) 546 return SCSI_DH_IO; 547 548 /* 549 * submit_rtpg() has failed on existing arrays 550 * when requesting extended header info, and 551 * the array doesn't support extended headers, 552 * even though it shouldn't according to T10. 553 * The retry without rtpg_ext_hdr_req set 554 * handles this. 555 */ 556 if (rtpg_ext_hdr_req == 1 && 557 sense_hdr.sense_key == ILLEGAL_REQUEST && 558 sense_hdr.asc == 0x24 && sense_hdr.ascq == 0) { 559 rtpg_ext_hdr_req = 0; 560 goto retry; 561 } 562 563 err = alua_check_sense(sdev, &sense_hdr); 564 if (err == ADD_TO_MLQUEUE && time_before(jiffies, expiry)) 565 goto retry; 566 sdev_printk(KERN_INFO, sdev, 567 "%s: rtpg sense code %02x/%02x/%02x\n", 568 ALUA_DH_NAME, sense_hdr.sense_key, 569 sense_hdr.asc, sense_hdr.ascq); 570 err = SCSI_DH_IO; 571 } 572 if (err != SCSI_DH_OK) 573 return err; 574 575 len = (h->buff[0] << 24) + (h->buff[1] << 16) + 576 (h->buff[2] << 8) + h->buff[3] + 4; 577 578 if (len > h->bufflen) { 579 /* Resubmit with the correct length */ 580 if (realloc_buffer(h, len)) { 581 sdev_printk(KERN_WARNING, sdev, 582 "%s: kmalloc buffer failed\n",__func__); 583 /* Temporary failure, bypass */ 584 return SCSI_DH_DEV_TEMP_BUSY; 585 } 586 goto retry; 587 } 588 589 orig_transition_tmo = h->transition_tmo; 590 if ((h->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR && h->buff[5] != 0) 591 h->transition_tmo = h->buff[5]; 592 else 593 h->transition_tmo = ALUA_FAILOVER_TIMEOUT; 594 595 if (orig_transition_tmo != h->transition_tmo) { 596 sdev_printk(KERN_INFO, sdev, 597 "%s: transition timeout set to %d seconds\n", 598 ALUA_DH_NAME, h->transition_tmo); 599 expiry = jiffies + h->transition_tmo * HZ; 600 } 601 602 if ((h->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR) 603 tpg_desc_tbl_off = 8; 604 else 605 tpg_desc_tbl_off = 4; 606 607 for (k = tpg_desc_tbl_off, ucp = h->buff + tpg_desc_tbl_off; 608 k < len; 609 k += off, ucp += off) { 610 611 if (h->group_id == (ucp[2] << 8) + ucp[3]) { 612 h->state = ucp[0] & 0x0f; 613 h->pref = ucp[0] >> 7; 614 valid_states = ucp[1]; 615 } 616 off = 8 + (ucp[7] * 4); 617 } 618 619 sdev_printk(KERN_INFO, sdev, 620 "%s: port group %02x state %c %s supports %c%c%c%c%c%c%c\n", 621 ALUA_DH_NAME, h->group_id, print_alua_state(h->state), 622 h->pref ? "preferred" : "non-preferred", 623 valid_states&TPGS_SUPPORT_TRANSITION?'T':'t', 624 valid_states&TPGS_SUPPORT_OFFLINE?'O':'o', 625 valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l', 626 valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u', 627 valid_states&TPGS_SUPPORT_STANDBY?'S':'s', 628 valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n', 629 valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a'); 630 631 switch (h->state) { 632 case TPGS_STATE_TRANSITIONING: 633 if (time_before(jiffies, expiry)) { 634 /* State transition, retry */ 635 interval += 2000; 636 msleep(interval); 637 goto retry; 638 } 639 /* Transitioning time exceeded, set port to standby */ 640 err = SCSI_DH_RETRY; 641 h->state = TPGS_STATE_STANDBY; 642 break; 643 case TPGS_STATE_OFFLINE: 644 case TPGS_STATE_UNAVAILABLE: 645 /* Path unusable for unavailable/offline */ 646 err = SCSI_DH_DEV_OFFLINED; 647 break; 648 default: 649 /* Useable path if active */ 650 err = SCSI_DH_OK; 651 break; 652 } 653 return err; 654 } 655 656 /* 657 * alua_initialize - Initialize ALUA state 658 * @sdev: the device to be initialized 659 * 660 * For the prep_fn to work correctly we have 661 * to initialize the ALUA state for the device. 662 */ 663 static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h) 664 { 665 int err; 666 667 err = alua_check_tpgs(sdev, h); 668 if (err != SCSI_DH_OK) 669 goto out; 670 671 err = alua_vpd_inquiry(sdev, h); 672 if (err != SCSI_DH_OK) 673 goto out; 674 675 err = alua_rtpg(sdev, h); 676 if (err != SCSI_DH_OK) 677 goto out; 678 679 out: 680 return err; 681 } 682 /* 683 * alua_set_params - set/unset the optimize flag 684 * @sdev: device on the path to be activated 685 * params - parameters in the following format 686 * "no_of_params\0param1\0param2\0param3\0...\0" 687 * For example, to set the flag pass the following parameters 688 * from multipath.conf 689 * hardware_handler "2 alua 1" 690 */ 691 static int alua_set_params(struct scsi_device *sdev, const char *params) 692 { 693 struct alua_dh_data *h = get_alua_data(sdev); 694 unsigned int optimize = 0, argc; 695 const char *p = params; 696 int result = SCSI_DH_OK; 697 698 if ((sscanf(params, "%u", &argc) != 1) || (argc != 1)) 699 return -EINVAL; 700 701 while (*p++) 702 ; 703 if ((sscanf(p, "%u", &optimize) != 1) || (optimize > 1)) 704 return -EINVAL; 705 706 if (optimize) 707 h->flags |= ALUA_OPTIMIZE_STPG; 708 else 709 h->flags &= ~ALUA_OPTIMIZE_STPG; 710 711 return result; 712 } 713 714 /* 715 * alua_activate - activate a path 716 * @sdev: device on the path to be activated 717 * 718 * We're currently switching the port group to be activated only and 719 * let the array figure out the rest. 720 * There may be other arrays which require us to switch all port groups 721 * based on a certain policy. But until we actually encounter them it 722 * should be okay. 723 */ 724 static int alua_activate(struct scsi_device *sdev, 725 activate_complete fn, void *data) 726 { 727 struct alua_dh_data *h = get_alua_data(sdev); 728 int err = SCSI_DH_OK; 729 int stpg = 0; 730 731 err = alua_rtpg(sdev, h); 732 if (err != SCSI_DH_OK) 733 goto out; 734 735 if (h->tpgs & TPGS_MODE_EXPLICIT) { 736 switch (h->state) { 737 case TPGS_STATE_NONOPTIMIZED: 738 stpg = 1; 739 if ((h->flags & ALUA_OPTIMIZE_STPG) && 740 (!h->pref) && 741 (h->tpgs & TPGS_MODE_IMPLICIT)) 742 stpg = 0; 743 break; 744 case TPGS_STATE_STANDBY: 745 case TPGS_STATE_UNAVAILABLE: 746 stpg = 1; 747 break; 748 case TPGS_STATE_OFFLINE: 749 err = SCSI_DH_IO; 750 break; 751 case TPGS_STATE_TRANSITIONING: 752 err = SCSI_DH_RETRY; 753 break; 754 default: 755 break; 756 } 757 } 758 759 if (stpg) { 760 h->callback_fn = fn; 761 h->callback_data = data; 762 err = submit_stpg(h); 763 if (err == SCSI_DH_OK) 764 return 0; 765 h->callback_fn = h->callback_data = NULL; 766 } 767 768 out: 769 if (fn) 770 fn(data, err); 771 return 0; 772 } 773 774 /* 775 * alua_prep_fn - request callback 776 * 777 * Fail I/O to all paths not in state 778 * active/optimized or active/non-optimized. 779 */ 780 static int alua_prep_fn(struct scsi_device *sdev, struct request *req) 781 { 782 struct alua_dh_data *h = get_alua_data(sdev); 783 int ret = BLKPREP_OK; 784 785 if (h->state == TPGS_STATE_TRANSITIONING) 786 ret = BLKPREP_DEFER; 787 else if (h->state != TPGS_STATE_OPTIMIZED && 788 h->state != TPGS_STATE_NONOPTIMIZED && 789 h->state != TPGS_STATE_LBA_DEPENDENT) { 790 ret = BLKPREP_KILL; 791 req->cmd_flags |= REQ_QUIET; 792 } 793 return ret; 794 795 } 796 797 static bool alua_match(struct scsi_device *sdev) 798 { 799 return (scsi_device_tpgs(sdev) != 0); 800 } 801 802 static int alua_bus_attach(struct scsi_device *sdev); 803 static void alua_bus_detach(struct scsi_device *sdev); 804 805 static struct scsi_device_handler alua_dh = { 806 .name = ALUA_DH_NAME, 807 .module = THIS_MODULE, 808 .attach = alua_bus_attach, 809 .detach = alua_bus_detach, 810 .prep_fn = alua_prep_fn, 811 .check_sense = alua_check_sense, 812 .activate = alua_activate, 813 .set_params = alua_set_params, 814 .match = alua_match, 815 }; 816 817 /* 818 * alua_bus_attach - Attach device handler 819 * @sdev: device to be attached to 820 */ 821 static int alua_bus_attach(struct scsi_device *sdev) 822 { 823 struct scsi_dh_data *scsi_dh_data; 824 struct alua_dh_data *h; 825 unsigned long flags; 826 int err = SCSI_DH_OK; 827 828 scsi_dh_data = kzalloc(sizeof(*scsi_dh_data) 829 + sizeof(*h) , GFP_KERNEL); 830 if (!scsi_dh_data) { 831 sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n", 832 ALUA_DH_NAME); 833 return -ENOMEM; 834 } 835 836 scsi_dh_data->scsi_dh = &alua_dh; 837 h = (struct alua_dh_data *) scsi_dh_data->buf; 838 h->tpgs = TPGS_MODE_UNINITIALIZED; 839 h->state = TPGS_STATE_OPTIMIZED; 840 h->group_id = -1; 841 h->rel_port = -1; 842 h->buff = h->inq; 843 h->bufflen = ALUA_INQUIRY_SIZE; 844 h->sdev = sdev; 845 846 err = alua_initialize(sdev, h); 847 if ((err != SCSI_DH_OK) && (err != SCSI_DH_DEV_OFFLINED)) 848 goto failed; 849 850 if (!try_module_get(THIS_MODULE)) 851 goto failed; 852 853 spin_lock_irqsave(sdev->request_queue->queue_lock, flags); 854 sdev->scsi_dh_data = scsi_dh_data; 855 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); 856 sdev_printk(KERN_NOTICE, sdev, "%s: Attached\n", ALUA_DH_NAME); 857 858 return 0; 859 860 failed: 861 kfree(scsi_dh_data); 862 sdev_printk(KERN_ERR, sdev, "%s: not attached\n", ALUA_DH_NAME); 863 return -EINVAL; 864 } 865 866 /* 867 * alua_bus_detach - Detach device handler 868 * @sdev: device to be detached from 869 */ 870 static void alua_bus_detach(struct scsi_device *sdev) 871 { 872 struct scsi_dh_data *scsi_dh_data; 873 struct alua_dh_data *h; 874 unsigned long flags; 875 876 spin_lock_irqsave(sdev->request_queue->queue_lock, flags); 877 scsi_dh_data = sdev->scsi_dh_data; 878 sdev->scsi_dh_data = NULL; 879 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); 880 881 h = (struct alua_dh_data *) scsi_dh_data->buf; 882 if (h->buff && h->inq != h->buff) 883 kfree(h->buff); 884 kfree(scsi_dh_data); 885 module_put(THIS_MODULE); 886 sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", ALUA_DH_NAME); 887 } 888 889 static int __init alua_init(void) 890 { 891 int r; 892 893 r = scsi_register_device_handler(&alua_dh); 894 if (r != 0) 895 printk(KERN_ERR "%s: Failed to register scsi device handler", 896 ALUA_DH_NAME); 897 return r; 898 } 899 900 static void __exit alua_exit(void) 901 { 902 scsi_unregister_device_handler(&alua_dh); 903 } 904 905 module_init(alua_init); 906 module_exit(alua_exit); 907 908 MODULE_DESCRIPTION("DM Multipath ALUA support"); 909 MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>"); 910 MODULE_LICENSE("GPL"); 911 MODULE_VERSION(ALUA_DH_VER); 912