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 int realloc_buffer(struct alua_dh_data *h, unsigned len) 89 { 90 if (h->buff && h->buff != h->inq) 91 kfree(h->buff); 92 93 h->buff = kmalloc(len, GFP_NOIO); 94 if (!h->buff) { 95 h->buff = h->inq; 96 h->bufflen = ALUA_INQUIRY_SIZE; 97 return 1; 98 } 99 h->bufflen = len; 100 return 0; 101 } 102 103 static struct request *get_alua_req(struct scsi_device *sdev, 104 void *buffer, unsigned buflen, int rw) 105 { 106 struct request *rq; 107 struct request_queue *q = sdev->request_queue; 108 109 rq = blk_get_request(q, rw, GFP_NOIO); 110 111 if (IS_ERR(rq)) { 112 sdev_printk(KERN_INFO, sdev, 113 "%s: blk_get_request failed\n", __func__); 114 return NULL; 115 } 116 blk_rq_set_block_pc(rq); 117 118 if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_NOIO)) { 119 blk_put_request(rq); 120 sdev_printk(KERN_INFO, sdev, 121 "%s: blk_rq_map_kern failed\n", __func__); 122 return NULL; 123 } 124 125 rq->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | 126 REQ_FAILFAST_DRIVER; 127 rq->retries = ALUA_FAILOVER_RETRIES; 128 rq->timeout = ALUA_FAILOVER_TIMEOUT * HZ; 129 130 return rq; 131 } 132 133 /* 134 * submit_vpd_inquiry - Issue an INQUIRY VPD page 0x83 command 135 * @sdev: sdev the command should be sent to 136 */ 137 static int submit_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h) 138 { 139 struct request *rq; 140 int err = SCSI_DH_RES_TEMP_UNAVAIL; 141 142 rq = get_alua_req(sdev, h->buff, h->bufflen, READ); 143 if (!rq) 144 goto done; 145 146 /* Prepare the command. */ 147 rq->cmd[0] = INQUIRY; 148 rq->cmd[1] = 1; 149 rq->cmd[2] = 0x83; 150 rq->cmd[4] = h->bufflen; 151 rq->cmd_len = COMMAND_SIZE(INQUIRY); 152 153 rq->sense = h->sense; 154 memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE); 155 rq->sense_len = h->senselen = 0; 156 157 err = blk_execute_rq(rq->q, NULL, rq, 1); 158 if (err == -EIO) { 159 sdev_printk(KERN_INFO, sdev, 160 "%s: evpd inquiry failed with %x\n", 161 ALUA_DH_NAME, rq->errors); 162 h->senselen = rq->sense_len; 163 err = SCSI_DH_IO; 164 } 165 blk_put_request(rq); 166 done: 167 return err; 168 } 169 170 /* 171 * submit_rtpg - Issue a REPORT TARGET GROUP STATES command 172 * @sdev: sdev the command should be sent to 173 */ 174 static unsigned submit_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, 175 bool rtpg_ext_hdr_req) 176 { 177 struct request *rq; 178 int err = SCSI_DH_RES_TEMP_UNAVAIL; 179 180 rq = get_alua_req(sdev, h->buff, h->bufflen, READ); 181 if (!rq) 182 goto done; 183 184 /* Prepare the command. */ 185 rq->cmd[0] = MAINTENANCE_IN; 186 if (rtpg_ext_hdr_req) 187 rq->cmd[1] = MI_REPORT_TARGET_PGS | MI_EXT_HDR_PARAM_FMT; 188 else 189 rq->cmd[1] = MI_REPORT_TARGET_PGS; 190 rq->cmd[6] = (h->bufflen >> 24) & 0xff; 191 rq->cmd[7] = (h->bufflen >> 16) & 0xff; 192 rq->cmd[8] = (h->bufflen >> 8) & 0xff; 193 rq->cmd[9] = h->bufflen & 0xff; 194 rq->cmd_len = COMMAND_SIZE(MAINTENANCE_IN); 195 196 rq->sense = h->sense; 197 memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE); 198 rq->sense_len = h->senselen = 0; 199 200 err = blk_execute_rq(rq->q, NULL, rq, 1); 201 if (err == -EIO) { 202 sdev_printk(KERN_INFO, sdev, 203 "%s: rtpg failed with %x\n", 204 ALUA_DH_NAME, rq->errors); 205 h->senselen = rq->sense_len; 206 err = SCSI_DH_IO; 207 } 208 blk_put_request(rq); 209 done: 210 return err; 211 } 212 213 /* 214 * alua_stpg - Evaluate SET TARGET GROUP STATES 215 * @sdev: the device to be evaluated 216 * @state: the new target group state 217 * 218 * Send a SET TARGET GROUP STATES command to the device. 219 * We only have to test here if we should resubmit the command; 220 * any other error is assumed as a failure. 221 */ 222 static void stpg_endio(struct request *req, int error) 223 { 224 struct alua_dh_data *h = req->end_io_data; 225 struct scsi_sense_hdr sense_hdr; 226 unsigned err = SCSI_DH_OK; 227 228 if (host_byte(req->errors) != DID_OK || 229 msg_byte(req->errors) != COMMAND_COMPLETE) { 230 err = SCSI_DH_IO; 231 goto done; 232 } 233 234 if (req->sense_len > 0) { 235 err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE, 236 &sense_hdr); 237 if (!err) { 238 err = SCSI_DH_IO; 239 goto done; 240 } 241 err = alua_check_sense(h->sdev, &sense_hdr); 242 if (err == ADD_TO_MLQUEUE) { 243 err = SCSI_DH_RETRY; 244 goto done; 245 } 246 sdev_printk(KERN_INFO, h->sdev, 247 "%s: stpg sense code: %02x/%02x/%02x\n", 248 ALUA_DH_NAME, sense_hdr.sense_key, 249 sense_hdr.asc, sense_hdr.ascq); 250 err = SCSI_DH_IO; 251 } else if (error) 252 err = SCSI_DH_IO; 253 254 if (err == SCSI_DH_OK) { 255 h->state = TPGS_STATE_OPTIMIZED; 256 sdev_printk(KERN_INFO, h->sdev, 257 "%s: port group %02x switched to state %c\n", 258 ALUA_DH_NAME, h->group_id, 259 print_alua_state(h->state)); 260 } 261 done: 262 req->end_io_data = NULL; 263 __blk_put_request(req->q, req); 264 if (h->callback_fn) { 265 h->callback_fn(h->callback_data, err); 266 h->callback_fn = h->callback_data = NULL; 267 } 268 return; 269 } 270 271 /* 272 * submit_stpg - Issue a SET TARGET GROUP STATES command 273 * 274 * Currently we're only setting the current target port group state 275 * to 'active/optimized' and let the array firmware figure out 276 * the states of the remaining groups. 277 */ 278 static unsigned submit_stpg(struct alua_dh_data *h) 279 { 280 struct request *rq; 281 int stpg_len = 8; 282 struct scsi_device *sdev = h->sdev; 283 284 /* Prepare the data buffer */ 285 memset(h->buff, 0, stpg_len); 286 h->buff[4] = TPGS_STATE_OPTIMIZED & 0x0f; 287 h->buff[6] = (h->group_id >> 8) & 0xff; 288 h->buff[7] = h->group_id & 0xff; 289 290 rq = get_alua_req(sdev, h->buff, stpg_len, WRITE); 291 if (!rq) 292 return SCSI_DH_RES_TEMP_UNAVAIL; 293 294 /* Prepare the command. */ 295 rq->cmd[0] = MAINTENANCE_OUT; 296 rq->cmd[1] = MO_SET_TARGET_PGS; 297 rq->cmd[6] = (stpg_len >> 24) & 0xff; 298 rq->cmd[7] = (stpg_len >> 16) & 0xff; 299 rq->cmd[8] = (stpg_len >> 8) & 0xff; 300 rq->cmd[9] = stpg_len & 0xff; 301 rq->cmd_len = COMMAND_SIZE(MAINTENANCE_OUT); 302 303 rq->sense = h->sense; 304 memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE); 305 rq->sense_len = h->senselen = 0; 306 rq->end_io_data = h; 307 308 blk_execute_rq_nowait(rq->q, NULL, rq, 1, stpg_endio); 309 return SCSI_DH_OK; 310 } 311 312 /* 313 * alua_check_tpgs - Evaluate TPGS setting 314 * @sdev: device to be checked 315 * 316 * Examine the TPGS setting of the sdev to find out if ALUA 317 * is supported. 318 */ 319 static int alua_check_tpgs(struct scsi_device *sdev, struct alua_dh_data *h) 320 { 321 int err = SCSI_DH_OK; 322 323 h->tpgs = scsi_device_tpgs(sdev); 324 switch (h->tpgs) { 325 case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT: 326 sdev_printk(KERN_INFO, sdev, 327 "%s: supports implicit and explicit TPGS\n", 328 ALUA_DH_NAME); 329 break; 330 case TPGS_MODE_EXPLICIT: 331 sdev_printk(KERN_INFO, sdev, "%s: supports explicit TPGS\n", 332 ALUA_DH_NAME); 333 break; 334 case TPGS_MODE_IMPLICIT: 335 sdev_printk(KERN_INFO, sdev, "%s: supports implicit TPGS\n", 336 ALUA_DH_NAME); 337 break; 338 default: 339 h->tpgs = TPGS_MODE_NONE; 340 sdev_printk(KERN_INFO, sdev, "%s: not supported\n", 341 ALUA_DH_NAME); 342 err = SCSI_DH_DEV_UNSUPP; 343 break; 344 } 345 346 return err; 347 } 348 349 /* 350 * alua_vpd_inquiry - Evaluate INQUIRY vpd page 0x83 351 * @sdev: device to be checked 352 * 353 * Extract the relative target port and the target port group 354 * descriptor from the list of identificators. 355 */ 356 static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h) 357 { 358 int len; 359 unsigned err; 360 unsigned char *d; 361 362 retry: 363 err = submit_vpd_inquiry(sdev, h); 364 365 if (err != SCSI_DH_OK) 366 return err; 367 368 /* Check if vpd page exceeds initial buffer */ 369 len = (h->buff[2] << 8) + h->buff[3] + 4; 370 if (len > h->bufflen) { 371 /* Resubmit with the correct length */ 372 if (realloc_buffer(h, len)) { 373 sdev_printk(KERN_WARNING, sdev, 374 "%s: kmalloc buffer failed\n", 375 ALUA_DH_NAME); 376 /* Temporary failure, bypass */ 377 return SCSI_DH_DEV_TEMP_BUSY; 378 } 379 goto retry; 380 } 381 382 /* 383 * Now look for the correct descriptor. 384 */ 385 d = h->buff + 4; 386 while (d < h->buff + len) { 387 switch (d[1] & 0xf) { 388 case 0x4: 389 /* Relative target port */ 390 h->rel_port = (d[6] << 8) + d[7]; 391 break; 392 case 0x5: 393 /* Target port group */ 394 h->group_id = (d[6] << 8) + d[7]; 395 break; 396 default: 397 break; 398 } 399 d += d[3] + 4; 400 } 401 402 if (h->group_id == -1) { 403 /* 404 * Internal error; TPGS supported but required 405 * VPD identification descriptors not present. 406 * Disable ALUA support 407 */ 408 sdev_printk(KERN_INFO, sdev, 409 "%s: No target port descriptors found\n", 410 ALUA_DH_NAME); 411 h->state = TPGS_STATE_OPTIMIZED; 412 h->tpgs = TPGS_MODE_NONE; 413 err = SCSI_DH_DEV_UNSUPP; 414 } else { 415 sdev_printk(KERN_INFO, sdev, 416 "%s: port group %02x rel port %02x\n", 417 ALUA_DH_NAME, h->group_id, h->rel_port); 418 } 419 420 return err; 421 } 422 423 static char print_alua_state(int state) 424 { 425 switch (state) { 426 case TPGS_STATE_OPTIMIZED: 427 return 'A'; 428 case TPGS_STATE_NONOPTIMIZED: 429 return 'N'; 430 case TPGS_STATE_STANDBY: 431 return 'S'; 432 case TPGS_STATE_UNAVAILABLE: 433 return 'U'; 434 case TPGS_STATE_LBA_DEPENDENT: 435 return 'L'; 436 case TPGS_STATE_OFFLINE: 437 return 'O'; 438 case TPGS_STATE_TRANSITIONING: 439 return 'T'; 440 default: 441 return 'X'; 442 } 443 } 444 445 static int alua_check_sense(struct scsi_device *sdev, 446 struct scsi_sense_hdr *sense_hdr) 447 { 448 switch (sense_hdr->sense_key) { 449 case NOT_READY: 450 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a) 451 /* 452 * LUN Not Accessible - ALUA state transition 453 */ 454 return ADD_TO_MLQUEUE; 455 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0b) 456 /* 457 * LUN Not Accessible -- Target port in standby state 458 */ 459 return SUCCESS; 460 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0c) 461 /* 462 * LUN Not Accessible -- Target port in unavailable state 463 */ 464 return SUCCESS; 465 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x12) 466 /* 467 * LUN Not Ready -- Offline 468 */ 469 return SUCCESS; 470 if (sdev->allow_restart && 471 sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x02) 472 /* 473 * if the device is not started, we need to wake 474 * the error handler to start the motor 475 */ 476 return FAILED; 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 = sdev->handler_data; 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 = sdev->handler_data; 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 = sdev->handler_data; 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 /* 817 * alua_bus_attach - Attach device handler 818 * @sdev: device to be attached to 819 */ 820 static int alua_bus_attach(struct scsi_device *sdev) 821 { 822 struct alua_dh_data *h; 823 int err; 824 825 h = kzalloc(sizeof(*h) , GFP_KERNEL); 826 if (!h) 827 return -ENOMEM; 828 h->tpgs = TPGS_MODE_UNINITIALIZED; 829 h->state = TPGS_STATE_OPTIMIZED; 830 h->group_id = -1; 831 h->rel_port = -1; 832 h->buff = h->inq; 833 h->bufflen = ALUA_INQUIRY_SIZE; 834 h->sdev = sdev; 835 836 err = alua_initialize(sdev, h); 837 if (err != SCSI_DH_OK && err != SCSI_DH_DEV_OFFLINED) 838 goto failed; 839 840 sdev->handler_data = h; 841 return 0; 842 failed: 843 kfree(h); 844 return -EINVAL; 845 } 846 847 /* 848 * alua_bus_detach - Detach device handler 849 * @sdev: device to be detached from 850 */ 851 static void alua_bus_detach(struct scsi_device *sdev) 852 { 853 struct alua_dh_data *h = sdev->handler_data; 854 855 if (h->buff && h->inq != h->buff) 856 kfree(h->buff); 857 sdev->handler_data = NULL; 858 kfree(h); 859 } 860 861 static struct scsi_device_handler alua_dh = { 862 .name = ALUA_DH_NAME, 863 .module = THIS_MODULE, 864 .attach = alua_bus_attach, 865 .detach = alua_bus_detach, 866 .prep_fn = alua_prep_fn, 867 .check_sense = alua_check_sense, 868 .activate = alua_activate, 869 .set_params = alua_set_params, 870 }; 871 872 static int __init alua_init(void) 873 { 874 int r; 875 876 r = scsi_register_device_handler(&alua_dh); 877 if (r != 0) 878 printk(KERN_ERR "%s: Failed to register scsi device handler", 879 ALUA_DH_NAME); 880 return r; 881 } 882 883 static void __exit alua_exit(void) 884 { 885 scsi_unregister_device_handler(&alua_dh); 886 } 887 888 module_init(alua_init); 889 module_exit(alua_exit); 890 891 MODULE_DESCRIPTION("DM Multipath ALUA support"); 892 MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>"); 893 MODULE_LICENSE("GPL"); 894 MODULE_VERSION(ALUA_DH_VER); 895