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 (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 (req->sense_len > 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 } else if (error) 259 err = SCSI_DH_IO; 260 261 if (err == SCSI_DH_OK) { 262 h->state = TPGS_STATE_OPTIMIZED; 263 sdev_printk(KERN_INFO, h->sdev, 264 "%s: port group %02x switched to state %c\n", 265 ALUA_DH_NAME, h->group_id, 266 print_alua_state(h->state)); 267 } 268 done: 269 req->end_io_data = NULL; 270 __blk_put_request(req->q, req); 271 if (h->callback_fn) { 272 h->callback_fn(h->callback_data, err); 273 h->callback_fn = h->callback_data = NULL; 274 } 275 return; 276 } 277 278 /* 279 * submit_stpg - Issue a SET TARGET GROUP STATES command 280 * 281 * Currently we're only setting the current target port group state 282 * to 'active/optimized' and let the array firmware figure out 283 * the states of the remaining groups. 284 */ 285 static unsigned submit_stpg(struct alua_dh_data *h) 286 { 287 struct request *rq; 288 int stpg_len = 8; 289 struct scsi_device *sdev = h->sdev; 290 291 /* Prepare the data buffer */ 292 memset(h->buff, 0, stpg_len); 293 h->buff[4] = TPGS_STATE_OPTIMIZED & 0x0f; 294 h->buff[6] = (h->group_id >> 8) & 0xff; 295 h->buff[7] = h->group_id & 0xff; 296 297 rq = get_alua_req(sdev, h->buff, stpg_len, WRITE); 298 if (!rq) 299 return SCSI_DH_RES_TEMP_UNAVAIL; 300 301 /* Prepare the command. */ 302 rq->cmd[0] = MAINTENANCE_OUT; 303 rq->cmd[1] = MO_SET_TARGET_PGS; 304 rq->cmd[6] = (stpg_len >> 24) & 0xff; 305 rq->cmd[7] = (stpg_len >> 16) & 0xff; 306 rq->cmd[8] = (stpg_len >> 8) & 0xff; 307 rq->cmd[9] = stpg_len & 0xff; 308 rq->cmd_len = COMMAND_SIZE(MAINTENANCE_OUT); 309 310 rq->sense = h->sense; 311 memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE); 312 rq->sense_len = h->senselen = 0; 313 rq->end_io_data = h; 314 315 blk_execute_rq_nowait(rq->q, NULL, rq, 1, stpg_endio); 316 return SCSI_DH_OK; 317 } 318 319 /* 320 * alua_check_tpgs - Evaluate TPGS setting 321 * @sdev: device to be checked 322 * 323 * Examine the TPGS setting of the sdev to find out if ALUA 324 * is supported. 325 */ 326 static int alua_check_tpgs(struct scsi_device *sdev, struct alua_dh_data *h) 327 { 328 int err = SCSI_DH_OK; 329 330 h->tpgs = scsi_device_tpgs(sdev); 331 switch (h->tpgs) { 332 case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT: 333 sdev_printk(KERN_INFO, sdev, 334 "%s: supports implicit and explicit TPGS\n", 335 ALUA_DH_NAME); 336 break; 337 case TPGS_MODE_EXPLICIT: 338 sdev_printk(KERN_INFO, sdev, "%s: supports explicit TPGS\n", 339 ALUA_DH_NAME); 340 break; 341 case TPGS_MODE_IMPLICIT: 342 sdev_printk(KERN_INFO, sdev, "%s: supports implicit TPGS\n", 343 ALUA_DH_NAME); 344 break; 345 default: 346 h->tpgs = TPGS_MODE_NONE; 347 sdev_printk(KERN_INFO, sdev, "%s: not supported\n", 348 ALUA_DH_NAME); 349 err = SCSI_DH_DEV_UNSUPP; 350 break; 351 } 352 353 return err; 354 } 355 356 /* 357 * alua_vpd_inquiry - Evaluate INQUIRY vpd page 0x83 358 * @sdev: device to be checked 359 * 360 * Extract the relative target port and the target port group 361 * descriptor from the list of identificators. 362 */ 363 static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h) 364 { 365 int len; 366 unsigned err; 367 unsigned char *d; 368 369 retry: 370 err = submit_vpd_inquiry(sdev, h); 371 372 if (err != SCSI_DH_OK) 373 return err; 374 375 /* Check if vpd page exceeds initial buffer */ 376 len = (h->buff[2] << 8) + h->buff[3] + 4; 377 if (len > h->bufflen) { 378 /* Resubmit with the correct length */ 379 if (realloc_buffer(h, len)) { 380 sdev_printk(KERN_WARNING, sdev, 381 "%s: kmalloc buffer failed\n", 382 ALUA_DH_NAME); 383 /* Temporary failure, bypass */ 384 return SCSI_DH_DEV_TEMP_BUSY; 385 } 386 goto retry; 387 } 388 389 /* 390 * Now look for the correct descriptor. 391 */ 392 d = h->buff + 4; 393 while (d < h->buff + len) { 394 switch (d[1] & 0xf) { 395 case 0x4: 396 /* Relative target port */ 397 h->rel_port = (d[6] << 8) + d[7]; 398 break; 399 case 0x5: 400 /* Target port group */ 401 h->group_id = (d[6] << 8) + d[7]; 402 break; 403 default: 404 break; 405 } 406 d += d[3] + 4; 407 } 408 409 if (h->group_id == -1) { 410 /* 411 * Internal error; TPGS supported but required 412 * VPD identification descriptors not present. 413 * Disable ALUA support 414 */ 415 sdev_printk(KERN_INFO, sdev, 416 "%s: No target port descriptors found\n", 417 ALUA_DH_NAME); 418 h->state = TPGS_STATE_OPTIMIZED; 419 h->tpgs = TPGS_MODE_NONE; 420 err = SCSI_DH_DEV_UNSUPP; 421 } else { 422 sdev_printk(KERN_INFO, sdev, 423 "%s: port group %02x rel port %02x\n", 424 ALUA_DH_NAME, h->group_id, h->rel_port); 425 } 426 427 return err; 428 } 429 430 static char print_alua_state(int state) 431 { 432 switch (state) { 433 case TPGS_STATE_OPTIMIZED: 434 return 'A'; 435 case TPGS_STATE_NONOPTIMIZED: 436 return 'N'; 437 case TPGS_STATE_STANDBY: 438 return 'S'; 439 case TPGS_STATE_UNAVAILABLE: 440 return 'U'; 441 case TPGS_STATE_LBA_DEPENDENT: 442 return 'L'; 443 case TPGS_STATE_OFFLINE: 444 return 'O'; 445 case TPGS_STATE_TRANSITIONING: 446 return 'T'; 447 default: 448 return 'X'; 449 } 450 } 451 452 static int alua_check_sense(struct scsi_device *sdev, 453 struct scsi_sense_hdr *sense_hdr) 454 { 455 switch (sense_hdr->sense_key) { 456 case NOT_READY: 457 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a) 458 /* 459 * LUN Not Accessible - ALUA state transition 460 */ 461 return ADD_TO_MLQUEUE; 462 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0b) 463 /* 464 * LUN Not Accessible -- Target port in standby state 465 */ 466 return SUCCESS; 467 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0c) 468 /* 469 * LUN Not Accessible -- Target port in unavailable state 470 */ 471 return SUCCESS; 472 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x12) 473 /* 474 * LUN Not Ready -- Offline 475 */ 476 return SUCCESS; 477 break; 478 case UNIT_ATTENTION: 479 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00) 480 /* 481 * Power On, Reset, or Bus Device Reset, just retry. 482 */ 483 return ADD_TO_MLQUEUE; 484 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x01) 485 /* 486 * Mode Parameters Changed 487 */ 488 return ADD_TO_MLQUEUE; 489 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) 490 /* 491 * ALUA state changed 492 */ 493 return ADD_TO_MLQUEUE; 494 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) 495 /* 496 * Implicit ALUA state transition failed 497 */ 498 return ADD_TO_MLQUEUE; 499 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x03) 500 /* 501 * Inquiry data has changed 502 */ 503 return ADD_TO_MLQUEUE; 504 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x0e) 505 /* 506 * REPORTED_LUNS_DATA_HAS_CHANGED is reported 507 * when switching controllers on targets like 508 * Intel Multi-Flex. We can just retry. 509 */ 510 return ADD_TO_MLQUEUE; 511 break; 512 } 513 514 return SCSI_RETURN_NOT_HANDLED; 515 } 516 517 /* 518 * alua_rtpg - Evaluate REPORT TARGET GROUP STATES 519 * @sdev: the device to be evaluated. 520 * 521 * Evaluate the Target Port Group State. 522 * Returns SCSI_DH_DEV_OFFLINED if the path is 523 * found to be unusable. 524 */ 525 static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h) 526 { 527 struct scsi_sense_hdr sense_hdr; 528 int len, k, off, valid_states = 0; 529 unsigned char *ucp; 530 unsigned err; 531 bool rtpg_ext_hdr_req = 1; 532 unsigned long expiry, interval = 0; 533 unsigned int tpg_desc_tbl_off; 534 unsigned char orig_transition_tmo; 535 536 if (!h->transition_tmo) 537 expiry = round_jiffies_up(jiffies + ALUA_FAILOVER_TIMEOUT * HZ); 538 else 539 expiry = round_jiffies_up(jiffies + h->transition_tmo * HZ); 540 541 retry: 542 err = submit_rtpg(sdev, h, rtpg_ext_hdr_req); 543 544 if (err == SCSI_DH_IO && h->senselen > 0) { 545 err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE, 546 &sense_hdr); 547 if (!err) 548 return SCSI_DH_IO; 549 550 /* 551 * submit_rtpg() has failed on existing arrays 552 * when requesting extended header info, and 553 * the array doesn't support extended headers, 554 * even though it shouldn't according to T10. 555 * The retry without rtpg_ext_hdr_req set 556 * handles this. 557 */ 558 if (rtpg_ext_hdr_req == 1 && 559 sense_hdr.sense_key == ILLEGAL_REQUEST && 560 sense_hdr.asc == 0x24 && sense_hdr.ascq == 0) { 561 rtpg_ext_hdr_req = 0; 562 goto retry; 563 } 564 565 err = alua_check_sense(sdev, &sense_hdr); 566 if (err == ADD_TO_MLQUEUE && time_before(jiffies, expiry)) 567 goto retry; 568 sdev_printk(KERN_INFO, sdev, 569 "%s: rtpg sense code %02x/%02x/%02x\n", 570 ALUA_DH_NAME, sense_hdr.sense_key, 571 sense_hdr.asc, sense_hdr.ascq); 572 err = SCSI_DH_IO; 573 } 574 if (err != SCSI_DH_OK) 575 return err; 576 577 len = (h->buff[0] << 24) + (h->buff[1] << 16) + 578 (h->buff[2] << 8) + h->buff[3] + 4; 579 580 if (len > h->bufflen) { 581 /* Resubmit with the correct length */ 582 if (realloc_buffer(h, len)) { 583 sdev_printk(KERN_WARNING, sdev, 584 "%s: kmalloc buffer failed\n",__func__); 585 /* Temporary failure, bypass */ 586 return SCSI_DH_DEV_TEMP_BUSY; 587 } 588 goto retry; 589 } 590 591 orig_transition_tmo = h->transition_tmo; 592 if ((h->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR && h->buff[5] != 0) 593 h->transition_tmo = h->buff[5]; 594 else 595 h->transition_tmo = ALUA_FAILOVER_TIMEOUT; 596 597 if (orig_transition_tmo != h->transition_tmo) { 598 sdev_printk(KERN_INFO, sdev, 599 "%s: transition timeout set to %d seconds\n", 600 ALUA_DH_NAME, h->transition_tmo); 601 expiry = jiffies + h->transition_tmo * HZ; 602 } 603 604 if ((h->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR) 605 tpg_desc_tbl_off = 8; 606 else 607 tpg_desc_tbl_off = 4; 608 609 for (k = tpg_desc_tbl_off, ucp = h->buff + tpg_desc_tbl_off; 610 k < len; 611 k += off, ucp += off) { 612 613 if (h->group_id == (ucp[2] << 8) + ucp[3]) { 614 h->state = ucp[0] & 0x0f; 615 h->pref = ucp[0] >> 7; 616 valid_states = ucp[1]; 617 } 618 off = 8 + (ucp[7] * 4); 619 } 620 621 sdev_printk(KERN_INFO, sdev, 622 "%s: port group %02x state %c %s supports %c%c%c%c%c%c%c\n", 623 ALUA_DH_NAME, h->group_id, print_alua_state(h->state), 624 h->pref ? "preferred" : "non-preferred", 625 valid_states&TPGS_SUPPORT_TRANSITION?'T':'t', 626 valid_states&TPGS_SUPPORT_OFFLINE?'O':'o', 627 valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l', 628 valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u', 629 valid_states&TPGS_SUPPORT_STANDBY?'S':'s', 630 valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n', 631 valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a'); 632 633 switch (h->state) { 634 case TPGS_STATE_TRANSITIONING: 635 if (time_before(jiffies, expiry)) { 636 /* State transition, retry */ 637 interval += 2000; 638 msleep(interval); 639 goto retry; 640 } 641 /* Transitioning time exceeded, set port to standby */ 642 err = SCSI_DH_RETRY; 643 h->state = TPGS_STATE_STANDBY; 644 break; 645 case TPGS_STATE_OFFLINE: 646 /* Path unusable */ 647 err = SCSI_DH_DEV_OFFLINED; 648 break; 649 default: 650 /* Useable path if active */ 651 err = SCSI_DH_OK; 652 break; 653 } 654 return err; 655 } 656 657 /* 658 * alua_initialize - Initialize ALUA state 659 * @sdev: the device to be initialized 660 * 661 * For the prep_fn to work correctly we have 662 * to initialize the ALUA state for the device. 663 */ 664 static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h) 665 { 666 int err; 667 668 err = alua_check_tpgs(sdev, h); 669 if (err != SCSI_DH_OK) 670 goto out; 671 672 err = alua_vpd_inquiry(sdev, h); 673 if (err != SCSI_DH_OK) 674 goto out; 675 676 err = alua_rtpg(sdev, h); 677 if (err != SCSI_DH_OK) 678 goto out; 679 680 out: 681 return err; 682 } 683 /* 684 * alua_set_params - set/unset the optimize flag 685 * @sdev: device on the path to be activated 686 * params - parameters in the following format 687 * "no_of_params\0param1\0param2\0param3\0...\0" 688 * For example, to set the flag pass the following parameters 689 * from multipath.conf 690 * hardware_handler "2 alua 1" 691 */ 692 static int alua_set_params(struct scsi_device *sdev, const char *params) 693 { 694 struct alua_dh_data *h = get_alua_data(sdev); 695 unsigned int optimize = 0, argc; 696 const char *p = params; 697 int result = SCSI_DH_OK; 698 699 if ((sscanf(params, "%u", &argc) != 1) || (argc != 1)) 700 return -EINVAL; 701 702 while (*p++) 703 ; 704 if ((sscanf(p, "%u", &optimize) != 1) || (optimize > 1)) 705 return -EINVAL; 706 707 if (optimize) 708 h->flags |= ALUA_OPTIMIZE_STPG; 709 else 710 h->flags &= ~ALUA_OPTIMIZE_STPG; 711 712 return result; 713 } 714 715 static uint optimize_stpg; 716 module_param(optimize_stpg, uint, S_IRUGO|S_IWUSR); 717 MODULE_PARM_DESC(optimize_stpg, "Allow use of a non-optimized path, rather than sending a STPG, when implicit TPGS is supported (0=No,1=Yes). Default is 0."); 718 719 /* 720 * alua_activate - activate a path 721 * @sdev: device on the path to be activated 722 * 723 * We're currently switching the port group to be activated only and 724 * let the array figure out the rest. 725 * There may be other arrays which require us to switch all port groups 726 * based on a certain policy. But until we actually encounter them it 727 * should be okay. 728 */ 729 static int alua_activate(struct scsi_device *sdev, 730 activate_complete fn, void *data) 731 { 732 struct alua_dh_data *h = get_alua_data(sdev); 733 int err = SCSI_DH_OK; 734 int stpg = 0; 735 736 err = alua_rtpg(sdev, h); 737 if (err != SCSI_DH_OK) 738 goto out; 739 740 if (optimize_stpg) 741 h->flags |= ALUA_OPTIMIZE_STPG; 742 743 if (h->tpgs & TPGS_MODE_EXPLICIT) { 744 switch (h->state) { 745 case TPGS_STATE_NONOPTIMIZED: 746 stpg = 1; 747 if ((h->flags & ALUA_OPTIMIZE_STPG) && 748 (!h->pref) && 749 (h->tpgs & TPGS_MODE_IMPLICIT)) 750 stpg = 0; 751 break; 752 case TPGS_STATE_STANDBY: 753 case TPGS_STATE_UNAVAILABLE: 754 stpg = 1; 755 break; 756 case TPGS_STATE_OFFLINE: 757 err = SCSI_DH_IO; 758 break; 759 case TPGS_STATE_TRANSITIONING: 760 err = SCSI_DH_RETRY; 761 break; 762 default: 763 break; 764 } 765 } 766 767 if (stpg) { 768 h->callback_fn = fn; 769 h->callback_data = data; 770 err = submit_stpg(h); 771 if (err == SCSI_DH_OK) 772 return 0; 773 h->callback_fn = h->callback_data = NULL; 774 } 775 776 out: 777 if (fn) 778 fn(data, err); 779 return 0; 780 } 781 782 /* 783 * alua_prep_fn - request callback 784 * 785 * Fail I/O to all paths not in state 786 * active/optimized or active/non-optimized. 787 */ 788 static int alua_prep_fn(struct scsi_device *sdev, struct request *req) 789 { 790 struct alua_dh_data *h = get_alua_data(sdev); 791 int ret = BLKPREP_OK; 792 793 if (h->state == TPGS_STATE_TRANSITIONING) 794 ret = BLKPREP_DEFER; 795 else if (h->state != TPGS_STATE_OPTIMIZED && 796 h->state != TPGS_STATE_NONOPTIMIZED && 797 h->state != TPGS_STATE_LBA_DEPENDENT) { 798 ret = BLKPREP_KILL; 799 req->cmd_flags |= REQ_QUIET; 800 } 801 return ret; 802 803 } 804 805 static bool alua_match(struct scsi_device *sdev) 806 { 807 return (scsi_device_tpgs(sdev) != 0); 808 } 809 810 static int alua_bus_attach(struct scsi_device *sdev); 811 static void alua_bus_detach(struct scsi_device *sdev); 812 813 static struct scsi_device_handler alua_dh = { 814 .name = ALUA_DH_NAME, 815 .module = THIS_MODULE, 816 .attach = alua_bus_attach, 817 .detach = alua_bus_detach, 818 .prep_fn = alua_prep_fn, 819 .check_sense = alua_check_sense, 820 .activate = alua_activate, 821 .set_params = alua_set_params, 822 .match = alua_match, 823 }; 824 825 /* 826 * alua_bus_attach - Attach device handler 827 * @sdev: device to be attached to 828 */ 829 static int alua_bus_attach(struct scsi_device *sdev) 830 { 831 struct scsi_dh_data *scsi_dh_data; 832 struct alua_dh_data *h; 833 unsigned long flags; 834 int err = SCSI_DH_OK; 835 836 scsi_dh_data = kzalloc(sizeof(*scsi_dh_data) 837 + sizeof(*h) , GFP_KERNEL); 838 if (!scsi_dh_data) { 839 sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n", 840 ALUA_DH_NAME); 841 return -ENOMEM; 842 } 843 844 scsi_dh_data->scsi_dh = &alua_dh; 845 h = (struct alua_dh_data *) scsi_dh_data->buf; 846 h->tpgs = TPGS_MODE_UNINITIALIZED; 847 h->state = TPGS_STATE_OPTIMIZED; 848 h->group_id = -1; 849 h->rel_port = -1; 850 h->buff = h->inq; 851 h->bufflen = ALUA_INQUIRY_SIZE; 852 h->sdev = sdev; 853 854 err = alua_initialize(sdev, h); 855 if ((err != SCSI_DH_OK) && (err != SCSI_DH_DEV_OFFLINED)) 856 goto failed; 857 858 if (!try_module_get(THIS_MODULE)) 859 goto failed; 860 861 spin_lock_irqsave(sdev->request_queue->queue_lock, flags); 862 sdev->scsi_dh_data = scsi_dh_data; 863 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); 864 sdev_printk(KERN_NOTICE, sdev, "%s: Attached\n", ALUA_DH_NAME); 865 866 return 0; 867 868 failed: 869 kfree(scsi_dh_data); 870 sdev_printk(KERN_ERR, sdev, "%s: not attached\n", ALUA_DH_NAME); 871 return -EINVAL; 872 } 873 874 /* 875 * alua_bus_detach - Detach device handler 876 * @sdev: device to be detached from 877 */ 878 static void alua_bus_detach(struct scsi_device *sdev) 879 { 880 struct scsi_dh_data *scsi_dh_data; 881 struct alua_dh_data *h; 882 unsigned long flags; 883 884 spin_lock_irqsave(sdev->request_queue->queue_lock, flags); 885 scsi_dh_data = sdev->scsi_dh_data; 886 sdev->scsi_dh_data = NULL; 887 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); 888 889 h = (struct alua_dh_data *) scsi_dh_data->buf; 890 if (h->buff && h->inq != h->buff) 891 kfree(h->buff); 892 kfree(scsi_dh_data); 893 module_put(THIS_MODULE); 894 sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", ALUA_DH_NAME); 895 } 896 897 static int __init alua_init(void) 898 { 899 int r; 900 901 r = scsi_register_device_handler(&alua_dh); 902 if (r != 0) 903 printk(KERN_ERR "%s: Failed to register scsi device handler", 904 ALUA_DH_NAME); 905 return r; 906 } 907 908 static void __exit alua_exit(void) 909 { 910 scsi_unregister_device_handler(&alua_dh); 911 } 912 913 module_init(alua_init); 914 module_exit(alua_exit); 915 916 MODULE_DESCRIPTION("DM Multipath ALUA support"); 917 MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>"); 918 MODULE_LICENSE("GPL"); 919 MODULE_VERSION(ALUA_DH_VER); 920