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