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 == 0x29 && sense_hdr->ascq == 0x04) 485 /* 486 * Device internal reset 487 */ 488 return ADD_TO_MLQUEUE; 489 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x01) 490 /* 491 * Mode Parameters Changed 492 */ 493 return ADD_TO_MLQUEUE; 494 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) 495 /* 496 * ALUA state changed 497 */ 498 return ADD_TO_MLQUEUE; 499 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) 500 /* 501 * Implicit ALUA state transition failed 502 */ 503 return ADD_TO_MLQUEUE; 504 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x03) 505 /* 506 * Inquiry data has changed 507 */ 508 return ADD_TO_MLQUEUE; 509 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x0e) 510 /* 511 * REPORTED_LUNS_DATA_HAS_CHANGED is reported 512 * when switching controllers on targets like 513 * Intel Multi-Flex. We can just retry. 514 */ 515 return ADD_TO_MLQUEUE; 516 break; 517 } 518 519 return SCSI_RETURN_NOT_HANDLED; 520 } 521 522 /* 523 * alua_rtpg - Evaluate REPORT TARGET GROUP STATES 524 * @sdev: the device to be evaluated. 525 * @wait_for_transition: if nonzero, wait ALUA_FAILOVER_TIMEOUT seconds for device to exit transitioning state 526 * 527 * Evaluate the Target Port Group State. 528 * Returns SCSI_DH_DEV_OFFLINED if the path is 529 * found to be unusable. 530 */ 531 static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_for_transition) 532 { 533 struct scsi_sense_hdr sense_hdr; 534 int len, k, off, valid_states = 0; 535 unsigned char *ucp; 536 unsigned err; 537 bool rtpg_ext_hdr_req = 1; 538 unsigned long expiry, interval = 0; 539 unsigned int tpg_desc_tbl_off; 540 unsigned char orig_transition_tmo; 541 542 if (!h->transition_tmo) 543 expiry = round_jiffies_up(jiffies + ALUA_FAILOVER_TIMEOUT * HZ); 544 else 545 expiry = round_jiffies_up(jiffies + h->transition_tmo * HZ); 546 547 retry: 548 err = submit_rtpg(sdev, h, rtpg_ext_hdr_req); 549 550 if (err == SCSI_DH_IO && h->senselen > 0) { 551 err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE, 552 &sense_hdr); 553 if (!err) 554 return SCSI_DH_IO; 555 556 /* 557 * submit_rtpg() has failed on existing arrays 558 * when requesting extended header info, and 559 * the array doesn't support extended headers, 560 * even though it shouldn't according to T10. 561 * The retry without rtpg_ext_hdr_req set 562 * handles this. 563 */ 564 if (rtpg_ext_hdr_req == 1 && 565 sense_hdr.sense_key == ILLEGAL_REQUEST && 566 sense_hdr.asc == 0x24 && sense_hdr.ascq == 0) { 567 rtpg_ext_hdr_req = 0; 568 goto retry; 569 } 570 571 err = alua_check_sense(sdev, &sense_hdr); 572 if (err == ADD_TO_MLQUEUE && time_before(jiffies, expiry)) 573 goto retry; 574 sdev_printk(KERN_INFO, sdev, 575 "%s: rtpg sense code %02x/%02x/%02x\n", 576 ALUA_DH_NAME, sense_hdr.sense_key, 577 sense_hdr.asc, sense_hdr.ascq); 578 err = SCSI_DH_IO; 579 } 580 if (err != SCSI_DH_OK) 581 return err; 582 583 len = (h->buff[0] << 24) + (h->buff[1] << 16) + 584 (h->buff[2] << 8) + h->buff[3] + 4; 585 586 if (len > h->bufflen) { 587 /* Resubmit with the correct length */ 588 if (realloc_buffer(h, len)) { 589 sdev_printk(KERN_WARNING, sdev, 590 "%s: kmalloc buffer failed\n",__func__); 591 /* Temporary failure, bypass */ 592 return SCSI_DH_DEV_TEMP_BUSY; 593 } 594 goto retry; 595 } 596 597 orig_transition_tmo = h->transition_tmo; 598 if ((h->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR && h->buff[5] != 0) 599 h->transition_tmo = h->buff[5]; 600 else 601 h->transition_tmo = ALUA_FAILOVER_TIMEOUT; 602 603 if (wait_for_transition && (orig_transition_tmo != h->transition_tmo)) { 604 sdev_printk(KERN_INFO, sdev, 605 "%s: transition timeout set to %d seconds\n", 606 ALUA_DH_NAME, h->transition_tmo); 607 expiry = jiffies + h->transition_tmo * HZ; 608 } 609 610 if ((h->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR) 611 tpg_desc_tbl_off = 8; 612 else 613 tpg_desc_tbl_off = 4; 614 615 for (k = tpg_desc_tbl_off, ucp = h->buff + tpg_desc_tbl_off; 616 k < len; 617 k += off, ucp += off) { 618 619 if (h->group_id == (ucp[2] << 8) + ucp[3]) { 620 h->state = ucp[0] & 0x0f; 621 h->pref = ucp[0] >> 7; 622 valid_states = ucp[1]; 623 } 624 off = 8 + (ucp[7] * 4); 625 } 626 627 sdev_printk(KERN_INFO, sdev, 628 "%s: port group %02x state %c %s supports %c%c%c%c%c%c%c\n", 629 ALUA_DH_NAME, h->group_id, print_alua_state(h->state), 630 h->pref ? "preferred" : "non-preferred", 631 valid_states&TPGS_SUPPORT_TRANSITION?'T':'t', 632 valid_states&TPGS_SUPPORT_OFFLINE?'O':'o', 633 valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l', 634 valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u', 635 valid_states&TPGS_SUPPORT_STANDBY?'S':'s', 636 valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n', 637 valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a'); 638 639 switch (h->state) { 640 case TPGS_STATE_TRANSITIONING: 641 if (wait_for_transition) { 642 if (time_before(jiffies, expiry)) { 643 /* State transition, retry */ 644 interval += 2000; 645 msleep(interval); 646 goto retry; 647 } 648 err = SCSI_DH_RETRY; 649 } else { 650 err = SCSI_DH_OK; 651 } 652 653 /* Transitioning time exceeded, set port to standby */ 654 h->state = TPGS_STATE_STANDBY; 655 break; 656 case TPGS_STATE_OFFLINE: 657 /* Path unusable */ 658 err = SCSI_DH_DEV_OFFLINED; 659 break; 660 default: 661 /* Useable path if active */ 662 err = SCSI_DH_OK; 663 break; 664 } 665 return err; 666 } 667 668 /* 669 * alua_initialize - Initialize ALUA state 670 * @sdev: the device to be initialized 671 * 672 * For the prep_fn to work correctly we have 673 * to initialize the ALUA state for the device. 674 */ 675 static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h) 676 { 677 int err; 678 679 err = alua_check_tpgs(sdev, h); 680 if (err != SCSI_DH_OK) 681 goto out; 682 683 err = alua_vpd_inquiry(sdev, h); 684 if (err != SCSI_DH_OK) 685 goto out; 686 687 err = alua_rtpg(sdev, h, 0); 688 if (err != SCSI_DH_OK) 689 goto out; 690 691 out: 692 return err; 693 } 694 /* 695 * alua_set_params - set/unset the optimize flag 696 * @sdev: device on the path to be activated 697 * params - parameters in the following format 698 * "no_of_params\0param1\0param2\0param3\0...\0" 699 * For example, to set the flag pass the following parameters 700 * from multipath.conf 701 * hardware_handler "2 alua 1" 702 */ 703 static int alua_set_params(struct scsi_device *sdev, const char *params) 704 { 705 struct alua_dh_data *h = get_alua_data(sdev); 706 unsigned int optimize = 0, argc; 707 const char *p = params; 708 int result = SCSI_DH_OK; 709 710 if ((sscanf(params, "%u", &argc) != 1) || (argc != 1)) 711 return -EINVAL; 712 713 while (*p++) 714 ; 715 if ((sscanf(p, "%u", &optimize) != 1) || (optimize > 1)) 716 return -EINVAL; 717 718 if (optimize) 719 h->flags |= ALUA_OPTIMIZE_STPG; 720 else 721 h->flags &= ~ALUA_OPTIMIZE_STPG; 722 723 return result; 724 } 725 726 static uint optimize_stpg; 727 module_param(optimize_stpg, uint, S_IRUGO|S_IWUSR); 728 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."); 729 730 /* 731 * alua_activate - activate a path 732 * @sdev: device on the path to be activated 733 * 734 * We're currently switching the port group to be activated only and 735 * let the array figure out the rest. 736 * There may be other arrays which require us to switch all port groups 737 * based on a certain policy. But until we actually encounter them it 738 * should be okay. 739 */ 740 static int alua_activate(struct scsi_device *sdev, 741 activate_complete fn, void *data) 742 { 743 struct alua_dh_data *h = get_alua_data(sdev); 744 int err = SCSI_DH_OK; 745 int stpg = 0; 746 747 err = alua_rtpg(sdev, h, 1); 748 if (err != SCSI_DH_OK) 749 goto out; 750 751 if (optimize_stpg) 752 h->flags |= ALUA_OPTIMIZE_STPG; 753 754 if (h->tpgs & TPGS_MODE_EXPLICIT) { 755 switch (h->state) { 756 case TPGS_STATE_NONOPTIMIZED: 757 stpg = 1; 758 if ((h->flags & ALUA_OPTIMIZE_STPG) && 759 (!h->pref) && 760 (h->tpgs & TPGS_MODE_IMPLICIT)) 761 stpg = 0; 762 break; 763 case TPGS_STATE_STANDBY: 764 case TPGS_STATE_UNAVAILABLE: 765 stpg = 1; 766 break; 767 case TPGS_STATE_OFFLINE: 768 err = SCSI_DH_IO; 769 break; 770 case TPGS_STATE_TRANSITIONING: 771 err = SCSI_DH_RETRY; 772 break; 773 default: 774 break; 775 } 776 } 777 778 if (stpg) { 779 h->callback_fn = fn; 780 h->callback_data = data; 781 err = submit_stpg(h); 782 if (err == SCSI_DH_OK) 783 return 0; 784 h->callback_fn = h->callback_data = NULL; 785 } 786 787 out: 788 if (fn) 789 fn(data, err); 790 return 0; 791 } 792 793 /* 794 * alua_prep_fn - request callback 795 * 796 * Fail I/O to all paths not in state 797 * active/optimized or active/non-optimized. 798 */ 799 static int alua_prep_fn(struct scsi_device *sdev, struct request *req) 800 { 801 struct alua_dh_data *h = get_alua_data(sdev); 802 int ret = BLKPREP_OK; 803 804 if (h->state == TPGS_STATE_TRANSITIONING) 805 ret = BLKPREP_DEFER; 806 else if (h->state != TPGS_STATE_OPTIMIZED && 807 h->state != TPGS_STATE_NONOPTIMIZED && 808 h->state != TPGS_STATE_LBA_DEPENDENT) { 809 ret = BLKPREP_KILL; 810 req->cmd_flags |= REQ_QUIET; 811 } 812 return ret; 813 814 } 815 816 static bool alua_match(struct scsi_device *sdev) 817 { 818 return (scsi_device_tpgs(sdev) != 0); 819 } 820 821 static int alua_bus_attach(struct scsi_device *sdev); 822 static void alua_bus_detach(struct scsi_device *sdev); 823 824 static struct scsi_device_handler alua_dh = { 825 .name = ALUA_DH_NAME, 826 .module = THIS_MODULE, 827 .attach = alua_bus_attach, 828 .detach = alua_bus_detach, 829 .prep_fn = alua_prep_fn, 830 .check_sense = alua_check_sense, 831 .activate = alua_activate, 832 .set_params = alua_set_params, 833 .match = alua_match, 834 }; 835 836 /* 837 * alua_bus_attach - Attach device handler 838 * @sdev: device to be attached to 839 */ 840 static int alua_bus_attach(struct scsi_device *sdev) 841 { 842 struct scsi_dh_data *scsi_dh_data; 843 struct alua_dh_data *h; 844 unsigned long flags; 845 int err = SCSI_DH_OK; 846 847 scsi_dh_data = kzalloc(sizeof(*scsi_dh_data) 848 + sizeof(*h) , GFP_KERNEL); 849 if (!scsi_dh_data) { 850 sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n", 851 ALUA_DH_NAME); 852 return -ENOMEM; 853 } 854 855 scsi_dh_data->scsi_dh = &alua_dh; 856 h = (struct alua_dh_data *) scsi_dh_data->buf; 857 h->tpgs = TPGS_MODE_UNINITIALIZED; 858 h->state = TPGS_STATE_OPTIMIZED; 859 h->group_id = -1; 860 h->rel_port = -1; 861 h->buff = h->inq; 862 h->bufflen = ALUA_INQUIRY_SIZE; 863 h->sdev = sdev; 864 865 err = alua_initialize(sdev, h); 866 if ((err != SCSI_DH_OK) && (err != SCSI_DH_DEV_OFFLINED)) 867 goto failed; 868 869 if (!try_module_get(THIS_MODULE)) 870 goto failed; 871 872 spin_lock_irqsave(sdev->request_queue->queue_lock, flags); 873 sdev->scsi_dh_data = scsi_dh_data; 874 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); 875 sdev_printk(KERN_NOTICE, sdev, "%s: Attached\n", ALUA_DH_NAME); 876 877 return 0; 878 879 failed: 880 kfree(scsi_dh_data); 881 sdev_printk(KERN_ERR, sdev, "%s: not attached\n", ALUA_DH_NAME); 882 return -EINVAL; 883 } 884 885 /* 886 * alua_bus_detach - Detach device handler 887 * @sdev: device to be detached from 888 */ 889 static void alua_bus_detach(struct scsi_device *sdev) 890 { 891 struct scsi_dh_data *scsi_dh_data; 892 struct alua_dh_data *h; 893 unsigned long flags; 894 895 spin_lock_irqsave(sdev->request_queue->queue_lock, flags); 896 scsi_dh_data = sdev->scsi_dh_data; 897 sdev->scsi_dh_data = NULL; 898 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); 899 900 h = (struct alua_dh_data *) scsi_dh_data->buf; 901 if (h->buff && h->inq != h->buff) 902 kfree(h->buff); 903 kfree(scsi_dh_data); 904 module_put(THIS_MODULE); 905 sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", ALUA_DH_NAME); 906 } 907 908 static int __init alua_init(void) 909 { 910 int r; 911 912 r = scsi_register_device_handler(&alua_dh); 913 if (r != 0) 914 printk(KERN_ERR "%s: Failed to register scsi device handler", 915 ALUA_DH_NAME); 916 return r; 917 } 918 919 static void __exit alua_exit(void) 920 { 921 scsi_unregister_device_handler(&alua_dh); 922 } 923 924 module_init(alua_init); 925 module_exit(alua_exit); 926 927 MODULE_DESCRIPTION("DM Multipath ALUA support"); 928 MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>"); 929 MODULE_LICENSE("GPL"); 930 MODULE_VERSION(ALUA_DH_VER); 931