1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * Generic SCSI-3 ALUA SCSI Device Handler 4 * 5 * Copyright (C) 2007-2010 Hannes Reinecke, SUSE Linux Products GmbH. 6 * All rights reserved. 7 */ 8#include <linux/slab.h> 9#include <linux/delay.h> 10#include <linux/module.h> 11#include <asm/unaligned.h> 12#include <scsi/scsi.h> 13#include <scsi/scsi_proto.h> 14#include <scsi/scsi_dbg.h> 15#include <scsi/scsi_eh.h> 16#include <scsi/scsi_dh.h> 17 18#define ALUA_DH_NAME "alua" 19#define ALUA_DH_VER "2.0" 20 21#define TPGS_SUPPORT_NONE 0x00 22#define TPGS_SUPPORT_OPTIMIZED 0x01 23#define TPGS_SUPPORT_NONOPTIMIZED 0x02 24#define TPGS_SUPPORT_STANDBY 0x04 25#define TPGS_SUPPORT_UNAVAILABLE 0x08 26#define TPGS_SUPPORT_LBA_DEPENDENT 0x10 27#define TPGS_SUPPORT_OFFLINE 0x40 28#define TPGS_SUPPORT_TRANSITION 0x80 29#define TPGS_SUPPORT_ALL 0xdf 30 31#define RTPG_FMT_MASK 0x70 32#define RTPG_FMT_EXT_HDR 0x10 33 34#define TPGS_MODE_UNINITIALIZED -1 35#define TPGS_MODE_NONE 0x0 36#define TPGS_MODE_IMPLICIT 0x1 37#define TPGS_MODE_EXPLICIT 0x2 38 39#define ALUA_RTPG_SIZE 128 40#define ALUA_FAILOVER_TIMEOUT 60 41#define ALUA_FAILOVER_RETRIES 5 42#define ALUA_RTPG_DELAY_MSECS 5 43#define ALUA_RTPG_RETRY_DELAY 2 44 45/* device handler flags */ 46#define ALUA_OPTIMIZE_STPG 0x01 47#define ALUA_RTPG_EXT_HDR_UNSUPP 0x02 48/* State machine flags */ 49#define ALUA_PG_RUN_RTPG 0x10 50#define ALUA_PG_RUN_STPG 0x20 51#define ALUA_PG_RUNNING 0x40 52 53static uint optimize_stpg; 54module_param(optimize_stpg, uint, S_IRUGO|S_IWUSR); 55MODULE_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."); 56 57static LIST_HEAD(port_group_list); 58static DEFINE_SPINLOCK(port_group_lock); 59static struct workqueue_struct *kaluad_wq; 60 61struct alua_port_group { 62 struct kref kref; 63 struct rcu_head rcu; 64 struct list_head node; 65 struct list_head dh_list; 66 unsigned char device_id_str[256]; 67 int device_id_len; 68 int group_id; 69 int tpgs; 70 int state; 71 int pref; 72 int valid_states; 73 unsigned flags; /* used for optimizing STPG */ 74 unsigned char transition_tmo; 75 unsigned long expiry; 76 unsigned long interval; 77 struct delayed_work rtpg_work; 78 spinlock_t lock; 79 struct list_head rtpg_list; 80 struct scsi_device *rtpg_sdev; 81}; 82 83struct alua_dh_data { 84 struct list_head node; 85 struct alua_port_group __rcu *pg; 86 int group_id; 87 spinlock_t pg_lock; 88 struct scsi_device *sdev; 89 int init_error; 90 struct mutex init_mutex; 91}; 92 93struct alua_queue_data { 94 struct list_head entry; 95 activate_complete callback_fn; 96 void *callback_data; 97}; 98 99#define ALUA_POLICY_SWITCH_CURRENT 0 100#define ALUA_POLICY_SWITCH_ALL 1 101 102static void alua_rtpg_work(struct work_struct *work); 103static bool alua_rtpg_queue(struct alua_port_group *pg, 104 struct scsi_device *sdev, 105 struct alua_queue_data *qdata, bool force); 106static void alua_check(struct scsi_device *sdev, bool force); 107 108static void release_port_group(struct kref *kref) 109{ 110 struct alua_port_group *pg; 111 112 pg = container_of(kref, struct alua_port_group, kref); 113 if (pg->rtpg_sdev) 114 flush_delayed_work(&pg->rtpg_work); 115 spin_lock(&port_group_lock); 116 list_del(&pg->node); 117 spin_unlock(&port_group_lock); 118 kfree_rcu(pg, rcu); 119} 120 121/* 122 * submit_rtpg - Issue a REPORT TARGET GROUP STATES command 123 * @sdev: sdev the command should be sent to 124 */ 125static int submit_rtpg(struct scsi_device *sdev, unsigned char *buff, 126 int bufflen, struct scsi_sense_hdr *sshdr, int flags) 127{ 128 u8 cdb[MAX_COMMAND_SIZE]; 129 int req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | 130 REQ_FAILFAST_DRIVER; 131 132 /* Prepare the command. */ 133 memset(cdb, 0x0, MAX_COMMAND_SIZE); 134 cdb[0] = MAINTENANCE_IN; 135 if (!(flags & ALUA_RTPG_EXT_HDR_UNSUPP)) 136 cdb[1] = MI_REPORT_TARGET_PGS | MI_EXT_HDR_PARAM_FMT; 137 else 138 cdb[1] = MI_REPORT_TARGET_PGS; 139 put_unaligned_be32(bufflen, &cdb[6]); 140 141 return scsi_execute(sdev, cdb, DMA_FROM_DEVICE, buff, bufflen, NULL, 142 sshdr, ALUA_FAILOVER_TIMEOUT * HZ, 143 ALUA_FAILOVER_RETRIES, req_flags, 0, NULL); 144} 145 146/* 147 * submit_stpg - Issue a SET TARGET PORT GROUP command 148 * 149 * Currently we're only setting the current target port group state 150 * to 'active/optimized' and let the array firmware figure out 151 * the states of the remaining groups. 152 */ 153static int submit_stpg(struct scsi_device *sdev, int group_id, 154 struct scsi_sense_hdr *sshdr) 155{ 156 u8 cdb[MAX_COMMAND_SIZE]; 157 unsigned char stpg_data[8]; 158 int stpg_len = 8; 159 int req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | 160 REQ_FAILFAST_DRIVER; 161 162 /* Prepare the data buffer */ 163 memset(stpg_data, 0, stpg_len); 164 stpg_data[4] = SCSI_ACCESS_STATE_OPTIMAL; 165 put_unaligned_be16(group_id, &stpg_data[6]); 166 167 /* Prepare the command. */ 168 memset(cdb, 0x0, MAX_COMMAND_SIZE); 169 cdb[0] = MAINTENANCE_OUT; 170 cdb[1] = MO_SET_TARGET_PGS; 171 put_unaligned_be32(stpg_len, &cdb[6]); 172 173 return scsi_execute(sdev, cdb, DMA_TO_DEVICE, stpg_data, stpg_len, NULL, 174 sshdr, ALUA_FAILOVER_TIMEOUT * HZ, 175 ALUA_FAILOVER_RETRIES, req_flags, 0, NULL); 176} 177 178static struct alua_port_group *alua_find_get_pg(char *id_str, size_t id_size, 179 int group_id) 180{ 181 struct alua_port_group *pg; 182 183 if (!id_str || !id_size || !strlen(id_str)) 184 return NULL; 185 186 list_for_each_entry(pg, &port_group_list, node) { 187 if (pg->group_id != group_id) 188 continue; 189 if (!pg->device_id_len || pg->device_id_len != id_size) 190 continue; 191 if (strncmp(pg->device_id_str, id_str, id_size)) 192 continue; 193 if (!kref_get_unless_zero(&pg->kref)) 194 continue; 195 return pg; 196 } 197 198 return NULL; 199} 200 201/* 202 * alua_alloc_pg - Allocate a new port_group structure 203 * @sdev: scsi device 204 * @group_id: port group id 205 * @tpgs: target port group settings 206 * 207 * Allocate a new port_group structure for a given 208 * device. 209 */ 210static struct alua_port_group *alua_alloc_pg(struct scsi_device *sdev, 211 int group_id, int tpgs) 212{ 213 struct alua_port_group *pg, *tmp_pg; 214 215 pg = kzalloc(sizeof(struct alua_port_group), GFP_KERNEL); 216 if (!pg) 217 return ERR_PTR(-ENOMEM); 218 219 pg->device_id_len = scsi_vpd_lun_id(sdev, pg->device_id_str, 220 sizeof(pg->device_id_str)); 221 if (pg->device_id_len <= 0) { 222 /* 223 * TPGS supported but no device identification found. 224 * Generate private device identification. 225 */ 226 sdev_printk(KERN_INFO, sdev, 227 "%s: No device descriptors found\n", 228 ALUA_DH_NAME); 229 pg->device_id_str[0] = '\0'; 230 pg->device_id_len = 0; 231 } 232 pg->group_id = group_id; 233 pg->tpgs = tpgs; 234 pg->state = SCSI_ACCESS_STATE_OPTIMAL; 235 pg->valid_states = TPGS_SUPPORT_ALL; 236 if (optimize_stpg) 237 pg->flags |= ALUA_OPTIMIZE_STPG; 238 kref_init(&pg->kref); 239 INIT_DELAYED_WORK(&pg->rtpg_work, alua_rtpg_work); 240 INIT_LIST_HEAD(&pg->rtpg_list); 241 INIT_LIST_HEAD(&pg->node); 242 INIT_LIST_HEAD(&pg->dh_list); 243 spin_lock_init(&pg->lock); 244 245 spin_lock(&port_group_lock); 246 tmp_pg = alua_find_get_pg(pg->device_id_str, pg->device_id_len, 247 group_id); 248 if (tmp_pg) { 249 spin_unlock(&port_group_lock); 250 kfree(pg); 251 return tmp_pg; 252 } 253 254 list_add(&pg->node, &port_group_list); 255 spin_unlock(&port_group_lock); 256 257 return pg; 258} 259 260/* 261 * alua_check_tpgs - Evaluate TPGS setting 262 * @sdev: device to be checked 263 * 264 * Examine the TPGS setting of the sdev to find out if ALUA 265 * is supported. 266 */ 267static int alua_check_tpgs(struct scsi_device *sdev) 268{ 269 int tpgs = TPGS_MODE_NONE; 270 271 /* 272 * ALUA support for non-disk devices is fraught with 273 * difficulties, so disable it for now. 274 */ 275 if (sdev->type != TYPE_DISK) { 276 sdev_printk(KERN_INFO, sdev, 277 "%s: disable for non-disk devices\n", 278 ALUA_DH_NAME); 279 return tpgs; 280 } 281 282 tpgs = scsi_device_tpgs(sdev); 283 switch (tpgs) { 284 case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT: 285 sdev_printk(KERN_INFO, sdev, 286 "%s: supports implicit and explicit TPGS\n", 287 ALUA_DH_NAME); 288 break; 289 case TPGS_MODE_EXPLICIT: 290 sdev_printk(KERN_INFO, sdev, "%s: supports explicit TPGS\n", 291 ALUA_DH_NAME); 292 break; 293 case TPGS_MODE_IMPLICIT: 294 sdev_printk(KERN_INFO, sdev, "%s: supports implicit TPGS\n", 295 ALUA_DH_NAME); 296 break; 297 case TPGS_MODE_NONE: 298 sdev_printk(KERN_INFO, sdev, "%s: not supported\n", 299 ALUA_DH_NAME); 300 break; 301 default: 302 sdev_printk(KERN_INFO, sdev, 303 "%s: unsupported TPGS setting %d\n", 304 ALUA_DH_NAME, tpgs); 305 tpgs = TPGS_MODE_NONE; 306 break; 307 } 308 309 return tpgs; 310} 311 312/* 313 * alua_check_vpd - Evaluate INQUIRY vpd page 0x83 314 * @sdev: device to be checked 315 * 316 * Extract the relative target port and the target port group 317 * descriptor from the list of identificators. 318 */ 319static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h, 320 int tpgs) 321{ 322 int rel_port = -1, group_id; 323 struct alua_port_group *pg, *old_pg = NULL; 324 bool pg_updated = false; 325 unsigned long flags; 326 327 group_id = scsi_vpd_tpg_id(sdev, &rel_port); 328 if (group_id < 0) { 329 /* 330 * Internal error; TPGS supported but required 331 * VPD identification descriptors not present. 332 * Disable ALUA support 333 */ 334 sdev_printk(KERN_INFO, sdev, 335 "%s: No target port descriptors found\n", 336 ALUA_DH_NAME); 337 return SCSI_DH_DEV_UNSUPP; 338 } 339 340 pg = alua_alloc_pg(sdev, group_id, tpgs); 341 if (IS_ERR(pg)) { 342 if (PTR_ERR(pg) == -ENOMEM) 343 return SCSI_DH_NOMEM; 344 return SCSI_DH_DEV_UNSUPP; 345 } 346 if (pg->device_id_len) 347 sdev_printk(KERN_INFO, sdev, 348 "%s: device %s port group %x rel port %x\n", 349 ALUA_DH_NAME, pg->device_id_str, 350 group_id, rel_port); 351 else 352 sdev_printk(KERN_INFO, sdev, 353 "%s: port group %x rel port %x\n", 354 ALUA_DH_NAME, group_id, rel_port); 355 356 /* Check for existing port group references */ 357 spin_lock(&h->pg_lock); 358 old_pg = rcu_dereference_protected(h->pg, lockdep_is_held(&h->pg_lock)); 359 if (old_pg != pg) { 360 /* port group has changed. Update to new port group */ 361 if (h->pg) { 362 spin_lock_irqsave(&old_pg->lock, flags); 363 list_del_rcu(&h->node); 364 spin_unlock_irqrestore(&old_pg->lock, flags); 365 } 366 rcu_assign_pointer(h->pg, pg); 367 pg_updated = true; 368 } 369 370 spin_lock_irqsave(&pg->lock, flags); 371 if (pg_updated) 372 list_add_rcu(&h->node, &pg->dh_list); 373 spin_unlock_irqrestore(&pg->lock, flags); 374 375 alua_rtpg_queue(rcu_dereference_protected(h->pg, 376 lockdep_is_held(&h->pg_lock)), 377 sdev, NULL, true); 378 spin_unlock(&h->pg_lock); 379 380 if (old_pg) 381 kref_put(&old_pg->kref, release_port_group); 382 383 return SCSI_DH_OK; 384} 385 386static char print_alua_state(unsigned char state) 387{ 388 switch (state) { 389 case SCSI_ACCESS_STATE_OPTIMAL: 390 return 'A'; 391 case SCSI_ACCESS_STATE_ACTIVE: 392 return 'N'; 393 case SCSI_ACCESS_STATE_STANDBY: 394 return 'S'; 395 case SCSI_ACCESS_STATE_UNAVAILABLE: 396 return 'U'; 397 case SCSI_ACCESS_STATE_LBA: 398 return 'L'; 399 case SCSI_ACCESS_STATE_OFFLINE: 400 return 'O'; 401 case SCSI_ACCESS_STATE_TRANSITIONING: 402 return 'T'; 403 default: 404 return 'X'; 405 } 406} 407 408static enum scsi_disposition alua_check_sense(struct scsi_device *sdev, 409 struct scsi_sense_hdr *sense_hdr) 410{ 411 switch (sense_hdr->sense_key) { 412 case NOT_READY: 413 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a) { 414 /* 415 * LUN Not Accessible - ALUA state transition 416 */ 417 alua_check(sdev, false); 418 return NEEDS_RETRY; 419 } 420 break; 421 case UNIT_ATTENTION: 422 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00) { 423 /* 424 * Power On, Reset, or Bus Device Reset. 425 * Might have obscured a state transition, 426 * so schedule a recheck. 427 */ 428 alua_check(sdev, true); 429 return ADD_TO_MLQUEUE; 430 } 431 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x04) 432 /* 433 * Device internal reset 434 */ 435 return ADD_TO_MLQUEUE; 436 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x01) 437 /* 438 * Mode Parameters Changed 439 */ 440 return ADD_TO_MLQUEUE; 441 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) { 442 /* 443 * ALUA state changed 444 */ 445 alua_check(sdev, true); 446 return ADD_TO_MLQUEUE; 447 } 448 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) { 449 /* 450 * Implicit ALUA state transition failed 451 */ 452 alua_check(sdev, true); 453 return ADD_TO_MLQUEUE; 454 } 455 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x03) 456 /* 457 * Inquiry data has changed 458 */ 459 return ADD_TO_MLQUEUE; 460 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x0e) 461 /* 462 * REPORTED_LUNS_DATA_HAS_CHANGED is reported 463 * when switching controllers on targets like 464 * Intel Multi-Flex. We can just retry. 465 */ 466 return ADD_TO_MLQUEUE; 467 break; 468 } 469 470 return SCSI_RETURN_NOT_HANDLED; 471} 472 473/* 474 * alua_tur - Send a TEST UNIT READY 475 * @sdev: device to which the TEST UNIT READY command should be send 476 * 477 * Send a TEST UNIT READY to @sdev to figure out the device state 478 * Returns SCSI_DH_RETRY if the sense code is NOT READY/ALUA TRANSITIONING, 479 * SCSI_DH_OK if no error occurred, and SCSI_DH_IO otherwise. 480 */ 481static int alua_tur(struct scsi_device *sdev) 482{ 483 struct scsi_sense_hdr sense_hdr; 484 int retval; 485 486 retval = scsi_test_unit_ready(sdev, ALUA_FAILOVER_TIMEOUT * HZ, 487 ALUA_FAILOVER_RETRIES, &sense_hdr); 488 if (sense_hdr.sense_key == NOT_READY && 489 sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a) 490 return SCSI_DH_RETRY; 491 else if (retval) 492 return SCSI_DH_IO; 493 else 494 return SCSI_DH_OK; 495} 496 497/* 498 * alua_rtpg - Evaluate REPORT TARGET GROUP STATES 499 * @sdev: the device to be evaluated. 500 * 501 * Evaluate the Target Port Group State. 502 * Returns SCSI_DH_DEV_OFFLINED if the path is 503 * found to be unusable. 504 */ 505static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg) 506{ 507 struct scsi_sense_hdr sense_hdr; 508 struct alua_port_group *tmp_pg; 509 int len, k, off, bufflen = ALUA_RTPG_SIZE; 510 unsigned char *desc, *buff; 511 unsigned err; 512 int retval; 513 unsigned int tpg_desc_tbl_off; 514 unsigned char orig_transition_tmo; 515 unsigned long flags; 516 bool transitioning_sense = false; 517 518 if (!pg->expiry) { 519 unsigned long transition_tmo = ALUA_FAILOVER_TIMEOUT * HZ; 520 521 if (pg->transition_tmo) 522 transition_tmo = pg->transition_tmo * HZ; 523 524 pg->expiry = round_jiffies_up(jiffies + transition_tmo); 525 } 526 527 buff = kzalloc(bufflen, GFP_KERNEL); 528 if (!buff) 529 return SCSI_DH_DEV_TEMP_BUSY; 530 531 retry: 532 err = 0; 533 retval = submit_rtpg(sdev, buff, bufflen, &sense_hdr, pg->flags); 534 535 if (retval) { 536 /* 537 * Some (broken) implementations have a habit of returning 538 * an error during things like firmware update etc. 539 * But if the target only supports active/optimized there's 540 * not much we can do; it's not that we can switch paths 541 * or anything. 542 * So ignore any errors to avoid spurious failures during 543 * path failover. 544 */ 545 if ((pg->valid_states & ~TPGS_SUPPORT_OPTIMIZED) == 0) { 546 sdev_printk(KERN_INFO, sdev, 547 "%s: ignoring rtpg result %d\n", 548 ALUA_DH_NAME, retval); 549 kfree(buff); 550 return SCSI_DH_OK; 551 } 552 if (retval < 0 || !scsi_sense_valid(&sense_hdr)) { 553 sdev_printk(KERN_INFO, sdev, 554 "%s: rtpg failed, result %d\n", 555 ALUA_DH_NAME, retval); 556 kfree(buff); 557 if (retval < 0) 558 return SCSI_DH_DEV_TEMP_BUSY; 559 return SCSI_DH_IO; 560 } 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 * Note: some arrays return a sense key of ILLEGAL_REQUEST 570 * with ASC 00h if they don't support the extended header. 571 */ 572 if (!(pg->flags & ALUA_RTPG_EXT_HDR_UNSUPP) && 573 sense_hdr.sense_key == ILLEGAL_REQUEST) { 574 pg->flags |= ALUA_RTPG_EXT_HDR_UNSUPP; 575 goto retry; 576 } 577 /* 578 * If the array returns with 'ALUA state transition' 579 * sense code here it cannot return RTPG data during 580 * transition. So set the state to 'transitioning' directly. 581 */ 582 if (sense_hdr.sense_key == NOT_READY && 583 sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a) { 584 transitioning_sense = true; 585 goto skip_rtpg; 586 } 587 /* 588 * Retry on any other UNIT ATTENTION occurred. 589 */ 590 if (sense_hdr.sense_key == UNIT_ATTENTION) 591 err = SCSI_DH_RETRY; 592 if (err == SCSI_DH_RETRY && 593 pg->expiry != 0 && time_before(jiffies, pg->expiry)) { 594 sdev_printk(KERN_ERR, sdev, "%s: rtpg retry\n", 595 ALUA_DH_NAME); 596 scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr); 597 kfree(buff); 598 return err; 599 } 600 sdev_printk(KERN_ERR, sdev, "%s: rtpg failed\n", 601 ALUA_DH_NAME); 602 scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr); 603 kfree(buff); 604 pg->expiry = 0; 605 return SCSI_DH_IO; 606 } 607 608 len = get_unaligned_be32(&buff[0]) + 4; 609 610 if (len > bufflen) { 611 /* Resubmit with the correct length */ 612 kfree(buff); 613 bufflen = len; 614 buff = kmalloc(bufflen, GFP_KERNEL); 615 if (!buff) { 616 sdev_printk(KERN_WARNING, sdev, 617 "%s: kmalloc buffer failed\n",__func__); 618 /* Temporary failure, bypass */ 619 pg->expiry = 0; 620 return SCSI_DH_DEV_TEMP_BUSY; 621 } 622 goto retry; 623 } 624 625 orig_transition_tmo = pg->transition_tmo; 626 if ((buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR && buff[5] != 0) 627 pg->transition_tmo = buff[5]; 628 else 629 pg->transition_tmo = ALUA_FAILOVER_TIMEOUT; 630 631 if (orig_transition_tmo != pg->transition_tmo) { 632 sdev_printk(KERN_INFO, sdev, 633 "%s: transition timeout set to %d seconds\n", 634 ALUA_DH_NAME, pg->transition_tmo); 635 pg->expiry = jiffies + pg->transition_tmo * HZ; 636 } 637 638 if ((buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR) 639 tpg_desc_tbl_off = 8; 640 else 641 tpg_desc_tbl_off = 4; 642 643 for (k = tpg_desc_tbl_off, desc = buff + tpg_desc_tbl_off; 644 k < len; 645 k += off, desc += off) { 646 u16 group_id = get_unaligned_be16(&desc[2]); 647 648 spin_lock_irqsave(&port_group_lock, flags); 649 tmp_pg = alua_find_get_pg(pg->device_id_str, pg->device_id_len, 650 group_id); 651 spin_unlock_irqrestore(&port_group_lock, flags); 652 if (tmp_pg) { 653 if (spin_trylock_irqsave(&tmp_pg->lock, flags)) { 654 if ((tmp_pg == pg) || 655 !(tmp_pg->flags & ALUA_PG_RUNNING)) { 656 struct alua_dh_data *h; 657 658 tmp_pg->state = desc[0] & 0x0f; 659 tmp_pg->pref = desc[0] >> 7; 660 rcu_read_lock(); 661 list_for_each_entry_rcu(h, 662 &tmp_pg->dh_list, node) { 663 if (!h->sdev) 664 continue; 665 h->sdev->access_state = desc[0]; 666 } 667 rcu_read_unlock(); 668 } 669 if (tmp_pg == pg) 670 tmp_pg->valid_states = desc[1]; 671 spin_unlock_irqrestore(&tmp_pg->lock, flags); 672 } 673 kref_put(&tmp_pg->kref, release_port_group); 674 } 675 off = 8 + (desc[7] * 4); 676 } 677 678 skip_rtpg: 679 spin_lock_irqsave(&pg->lock, flags); 680 if (transitioning_sense) 681 pg->state = SCSI_ACCESS_STATE_TRANSITIONING; 682 683 sdev_printk(KERN_INFO, sdev, 684 "%s: port group %02x state %c %s supports %c%c%c%c%c%c%c\n", 685 ALUA_DH_NAME, pg->group_id, print_alua_state(pg->state), 686 pg->pref ? "preferred" : "non-preferred", 687 pg->valid_states&TPGS_SUPPORT_TRANSITION?'T':'t', 688 pg->valid_states&TPGS_SUPPORT_OFFLINE?'O':'o', 689 pg->valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l', 690 pg->valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u', 691 pg->valid_states&TPGS_SUPPORT_STANDBY?'S':'s', 692 pg->valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n', 693 pg->valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a'); 694 695 switch (pg->state) { 696 case SCSI_ACCESS_STATE_TRANSITIONING: 697 if (time_before(jiffies, pg->expiry)) { 698 /* State transition, retry */ 699 pg->interval = ALUA_RTPG_RETRY_DELAY; 700 err = SCSI_DH_RETRY; 701 } else { 702 struct alua_dh_data *h; 703 704 /* Transitioning time exceeded, set port to standby */ 705 err = SCSI_DH_IO; 706 pg->state = SCSI_ACCESS_STATE_STANDBY; 707 pg->expiry = 0; 708 rcu_read_lock(); 709 list_for_each_entry_rcu(h, &pg->dh_list, node) { 710 if (!h->sdev) 711 continue; 712 h->sdev->access_state = 713 (pg->state & SCSI_ACCESS_STATE_MASK); 714 if (pg->pref) 715 h->sdev->access_state |= 716 SCSI_ACCESS_STATE_PREFERRED; 717 } 718 rcu_read_unlock(); 719 } 720 break; 721 case SCSI_ACCESS_STATE_OFFLINE: 722 /* Path unusable */ 723 err = SCSI_DH_DEV_OFFLINED; 724 pg->expiry = 0; 725 break; 726 default: 727 /* Useable path if active */ 728 err = SCSI_DH_OK; 729 pg->expiry = 0; 730 break; 731 } 732 spin_unlock_irqrestore(&pg->lock, flags); 733 kfree(buff); 734 return err; 735} 736 737/* 738 * alua_stpg - Issue a SET TARGET PORT GROUP command 739 * 740 * Issue a SET TARGET PORT GROUP command and evaluate the 741 * response. Returns SCSI_DH_RETRY per default to trigger 742 * a re-evaluation of the target group state or SCSI_DH_OK 743 * if no further action needs to be taken. 744 */ 745static unsigned alua_stpg(struct scsi_device *sdev, struct alua_port_group *pg) 746{ 747 int retval; 748 struct scsi_sense_hdr sense_hdr; 749 750 if (!(pg->tpgs & TPGS_MODE_EXPLICIT)) { 751 /* Only implicit ALUA supported, retry */ 752 return SCSI_DH_RETRY; 753 } 754 switch (pg->state) { 755 case SCSI_ACCESS_STATE_OPTIMAL: 756 return SCSI_DH_OK; 757 case SCSI_ACCESS_STATE_ACTIVE: 758 if ((pg->flags & ALUA_OPTIMIZE_STPG) && 759 !pg->pref && 760 (pg->tpgs & TPGS_MODE_IMPLICIT)) 761 return SCSI_DH_OK; 762 break; 763 case SCSI_ACCESS_STATE_STANDBY: 764 case SCSI_ACCESS_STATE_UNAVAILABLE: 765 break; 766 case SCSI_ACCESS_STATE_OFFLINE: 767 return SCSI_DH_IO; 768 case SCSI_ACCESS_STATE_TRANSITIONING: 769 break; 770 default: 771 sdev_printk(KERN_INFO, sdev, 772 "%s: stpg failed, unhandled TPGS state %d", 773 ALUA_DH_NAME, pg->state); 774 return SCSI_DH_NOSYS; 775 } 776 retval = submit_stpg(sdev, pg->group_id, &sense_hdr); 777 778 if (retval) { 779 if (retval < 0 || !scsi_sense_valid(&sense_hdr)) { 780 sdev_printk(KERN_INFO, sdev, 781 "%s: stpg failed, result %d", 782 ALUA_DH_NAME, retval); 783 if (retval < 0) 784 return SCSI_DH_DEV_TEMP_BUSY; 785 } else { 786 sdev_printk(KERN_INFO, sdev, "%s: stpg failed\n", 787 ALUA_DH_NAME); 788 scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr); 789 } 790 } 791 /* Retry RTPG */ 792 return SCSI_DH_RETRY; 793} 794 795static void alua_rtpg_work(struct work_struct *work) 796{ 797 struct alua_port_group *pg = 798 container_of(work, struct alua_port_group, rtpg_work.work); 799 struct scsi_device *sdev; 800 LIST_HEAD(qdata_list); 801 int err = SCSI_DH_OK; 802 struct alua_queue_data *qdata, *tmp; 803 unsigned long flags; 804 805 spin_lock_irqsave(&pg->lock, flags); 806 sdev = pg->rtpg_sdev; 807 if (!sdev) { 808 WARN_ON(pg->flags & ALUA_PG_RUN_RTPG); 809 WARN_ON(pg->flags & ALUA_PG_RUN_STPG); 810 spin_unlock_irqrestore(&pg->lock, flags); 811 kref_put(&pg->kref, release_port_group); 812 return; 813 } 814 pg->flags |= ALUA_PG_RUNNING; 815 if (pg->flags & ALUA_PG_RUN_RTPG) { 816 int state = pg->state; 817 818 pg->flags &= ~ALUA_PG_RUN_RTPG; 819 spin_unlock_irqrestore(&pg->lock, flags); 820 if (state == SCSI_ACCESS_STATE_TRANSITIONING) { 821 if (alua_tur(sdev) == SCSI_DH_RETRY) { 822 spin_lock_irqsave(&pg->lock, flags); 823 pg->flags &= ~ALUA_PG_RUNNING; 824 pg->flags |= ALUA_PG_RUN_RTPG; 825 if (!pg->interval) 826 pg->interval = ALUA_RTPG_RETRY_DELAY; 827 spin_unlock_irqrestore(&pg->lock, flags); 828 queue_delayed_work(kaluad_wq, &pg->rtpg_work, 829 pg->interval * HZ); 830 return; 831 } 832 /* Send RTPG on failure or if TUR indicates SUCCESS */ 833 } 834 err = alua_rtpg(sdev, pg); 835 spin_lock_irqsave(&pg->lock, flags); 836 if (err == SCSI_DH_RETRY || pg->flags & ALUA_PG_RUN_RTPG) { 837 pg->flags &= ~ALUA_PG_RUNNING; 838 if (!pg->interval && !(pg->flags & ALUA_PG_RUN_RTPG)) 839 pg->interval = ALUA_RTPG_RETRY_DELAY; 840 pg->flags |= ALUA_PG_RUN_RTPG; 841 spin_unlock_irqrestore(&pg->lock, flags); 842 queue_delayed_work(kaluad_wq, &pg->rtpg_work, 843 pg->interval * HZ); 844 return; 845 } 846 if (err != SCSI_DH_OK) 847 pg->flags &= ~ALUA_PG_RUN_STPG; 848 } 849 if (pg->flags & ALUA_PG_RUN_STPG) { 850 pg->flags &= ~ALUA_PG_RUN_STPG; 851 spin_unlock_irqrestore(&pg->lock, flags); 852 err = alua_stpg(sdev, pg); 853 spin_lock_irqsave(&pg->lock, flags); 854 if (err == SCSI_DH_RETRY || pg->flags & ALUA_PG_RUN_RTPG) { 855 pg->flags |= ALUA_PG_RUN_RTPG; 856 pg->interval = 0; 857 pg->flags &= ~ALUA_PG_RUNNING; 858 spin_unlock_irqrestore(&pg->lock, flags); 859 queue_delayed_work(kaluad_wq, &pg->rtpg_work, 860 pg->interval * HZ); 861 return; 862 } 863 } 864 865 list_splice_init(&pg->rtpg_list, &qdata_list); 866 pg->rtpg_sdev = NULL; 867 spin_unlock_irqrestore(&pg->lock, flags); 868 869 list_for_each_entry_safe(qdata, tmp, &qdata_list, entry) { 870 list_del(&qdata->entry); 871 if (qdata->callback_fn) 872 qdata->callback_fn(qdata->callback_data, err); 873 kfree(qdata); 874 } 875 spin_lock_irqsave(&pg->lock, flags); 876 pg->flags &= ~ALUA_PG_RUNNING; 877 spin_unlock_irqrestore(&pg->lock, flags); 878 scsi_device_put(sdev); 879 kref_put(&pg->kref, release_port_group); 880} 881 882/** 883 * alua_rtpg_queue() - cause RTPG to be submitted asynchronously 884 * @pg: ALUA port group associated with @sdev. 885 * @sdev: SCSI device for which to submit an RTPG. 886 * @qdata: Information about the callback to invoke after the RTPG. 887 * @force: Whether or not to submit an RTPG if a work item that will submit an 888 * RTPG already has been scheduled. 889 * 890 * Returns true if and only if alua_rtpg_work() will be called asynchronously. 891 * That function is responsible for calling @qdata->fn(). 892 */ 893static bool alua_rtpg_queue(struct alua_port_group *pg, 894 struct scsi_device *sdev, 895 struct alua_queue_data *qdata, bool force) 896{ 897 int start_queue = 0; 898 unsigned long flags; 899 if (WARN_ON_ONCE(!pg) || scsi_device_get(sdev)) 900 return false; 901 902 spin_lock_irqsave(&pg->lock, flags); 903 if (qdata) { 904 list_add_tail(&qdata->entry, &pg->rtpg_list); 905 pg->flags |= ALUA_PG_RUN_STPG; 906 force = true; 907 } 908 if (pg->rtpg_sdev == NULL) { 909 pg->interval = 0; 910 pg->flags |= ALUA_PG_RUN_RTPG; 911 kref_get(&pg->kref); 912 pg->rtpg_sdev = sdev; 913 start_queue = 1; 914 } else if (!(pg->flags & ALUA_PG_RUN_RTPG) && force) { 915 pg->flags |= ALUA_PG_RUN_RTPG; 916 /* Do not queue if the worker is already running */ 917 if (!(pg->flags & ALUA_PG_RUNNING)) { 918 kref_get(&pg->kref); 919 start_queue = 1; 920 } 921 } 922 923 spin_unlock_irqrestore(&pg->lock, flags); 924 925 if (start_queue) { 926 if (queue_delayed_work(kaluad_wq, &pg->rtpg_work, 927 msecs_to_jiffies(ALUA_RTPG_DELAY_MSECS))) 928 sdev = NULL; 929 else 930 kref_put(&pg->kref, release_port_group); 931 } 932 if (sdev) 933 scsi_device_put(sdev); 934 935 return true; 936} 937 938/* 939 * alua_initialize - Initialize ALUA state 940 * @sdev: the device to be initialized 941 * 942 * For the prep_fn to work correctly we have 943 * to initialize the ALUA state for the device. 944 */ 945static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h) 946{ 947 int err = SCSI_DH_DEV_UNSUPP, tpgs; 948 949 mutex_lock(&h->init_mutex); 950 tpgs = alua_check_tpgs(sdev); 951 if (tpgs != TPGS_MODE_NONE) 952 err = alua_check_vpd(sdev, h, tpgs); 953 h->init_error = err; 954 mutex_unlock(&h->init_mutex); 955 return err; 956} 957/* 958 * alua_set_params - set/unset the optimize flag 959 * @sdev: device on the path to be activated 960 * params - parameters in the following format 961 * "no_of_params\0param1\0param2\0param3\0...\0" 962 * For example, to set the flag pass the following parameters 963 * from multipath.conf 964 * hardware_handler "2 alua 1" 965 */ 966static int alua_set_params(struct scsi_device *sdev, const char *params) 967{ 968 struct alua_dh_data *h = sdev->handler_data; 969 struct alua_port_group *pg = NULL; 970 unsigned int optimize = 0, argc; 971 const char *p = params; 972 int result = SCSI_DH_OK; 973 unsigned long flags; 974 975 if ((sscanf(params, "%u", &argc) != 1) || (argc != 1)) 976 return -EINVAL; 977 978 while (*p++) 979 ; 980 if ((sscanf(p, "%u", &optimize) != 1) || (optimize > 1)) 981 return -EINVAL; 982 983 rcu_read_lock(); 984 pg = rcu_dereference(h->pg); 985 if (!pg) { 986 rcu_read_unlock(); 987 return -ENXIO; 988 } 989 spin_lock_irqsave(&pg->lock, flags); 990 if (optimize) 991 pg->flags |= ALUA_OPTIMIZE_STPG; 992 else 993 pg->flags &= ~ALUA_OPTIMIZE_STPG; 994 spin_unlock_irqrestore(&pg->lock, flags); 995 rcu_read_unlock(); 996 997 return result; 998} 999 1000/* 1001 * alua_activate - activate a path 1002 * @sdev: device on the path to be activated 1003 * 1004 * We're currently switching the port group to be activated only and 1005 * let the array figure out the rest. 1006 * There may be other arrays which require us to switch all port groups 1007 * based on a certain policy. But until we actually encounter them it 1008 * should be okay. 1009 */ 1010static int alua_activate(struct scsi_device *sdev, 1011 activate_complete fn, void *data) 1012{ 1013 struct alua_dh_data *h = sdev->handler_data; 1014 int err = SCSI_DH_OK; 1015 struct alua_queue_data *qdata; 1016 struct alua_port_group *pg; 1017 1018 qdata = kzalloc(sizeof(*qdata), GFP_KERNEL); 1019 if (!qdata) { 1020 err = SCSI_DH_RES_TEMP_UNAVAIL; 1021 goto out; 1022 } 1023 qdata->callback_fn = fn; 1024 qdata->callback_data = data; 1025 1026 mutex_lock(&h->init_mutex); 1027 rcu_read_lock(); 1028 pg = rcu_dereference(h->pg); 1029 if (!pg || !kref_get_unless_zero(&pg->kref)) { 1030 rcu_read_unlock(); 1031 kfree(qdata); 1032 err = h->init_error; 1033 mutex_unlock(&h->init_mutex); 1034 goto out; 1035 } 1036 rcu_read_unlock(); 1037 mutex_unlock(&h->init_mutex); 1038 1039 if (alua_rtpg_queue(pg, sdev, qdata, true)) { 1040 fn = NULL; 1041 } else { 1042 kfree(qdata); 1043 err = SCSI_DH_DEV_OFFLINED; 1044 } 1045 kref_put(&pg->kref, release_port_group); 1046out: 1047 if (fn) 1048 fn(data, err); 1049 return 0; 1050} 1051 1052/* 1053 * alua_check - check path status 1054 * @sdev: device on the path to be checked 1055 * 1056 * Check the device status 1057 */ 1058static void alua_check(struct scsi_device *sdev, bool force) 1059{ 1060 struct alua_dh_data *h = sdev->handler_data; 1061 struct alua_port_group *pg; 1062 1063 rcu_read_lock(); 1064 pg = rcu_dereference(h->pg); 1065 if (!pg || !kref_get_unless_zero(&pg->kref)) { 1066 rcu_read_unlock(); 1067 return; 1068 } 1069 rcu_read_unlock(); 1070 1071 alua_rtpg_queue(pg, sdev, NULL, force); 1072 kref_put(&pg->kref, release_port_group); 1073} 1074 1075/* 1076 * alua_prep_fn - request callback 1077 * 1078 * Fail I/O to all paths not in state 1079 * active/optimized or active/non-optimized. 1080 */ 1081static blk_status_t alua_prep_fn(struct scsi_device *sdev, struct request *req) 1082{ 1083 struct alua_dh_data *h = sdev->handler_data; 1084 struct alua_port_group *pg; 1085 unsigned char state = SCSI_ACCESS_STATE_OPTIMAL; 1086 1087 rcu_read_lock(); 1088 pg = rcu_dereference(h->pg); 1089 if (pg) 1090 state = pg->state; 1091 rcu_read_unlock(); 1092 1093 switch (state) { 1094 case SCSI_ACCESS_STATE_OPTIMAL: 1095 case SCSI_ACCESS_STATE_ACTIVE: 1096 case SCSI_ACCESS_STATE_LBA: 1097 return BLK_STS_OK; 1098 case SCSI_ACCESS_STATE_TRANSITIONING: 1099 return BLK_STS_RESOURCE; 1100 default: 1101 req->rq_flags |= RQF_QUIET; 1102 return BLK_STS_IOERR; 1103 } 1104} 1105 1106static void alua_rescan(struct scsi_device *sdev) 1107{ 1108 struct alua_dh_data *h = sdev->handler_data; 1109 1110 alua_initialize(sdev, h); 1111} 1112 1113/* 1114 * alua_bus_attach - Attach device handler 1115 * @sdev: device to be attached to 1116 */ 1117static int alua_bus_attach(struct scsi_device *sdev) 1118{ 1119 struct alua_dh_data *h; 1120 int err; 1121 1122 h = kzalloc(sizeof(*h) , GFP_KERNEL); 1123 if (!h) 1124 return SCSI_DH_NOMEM; 1125 spin_lock_init(&h->pg_lock); 1126 rcu_assign_pointer(h->pg, NULL); 1127 h->init_error = SCSI_DH_OK; 1128 h->sdev = sdev; 1129 INIT_LIST_HEAD(&h->node); 1130 1131 mutex_init(&h->init_mutex); 1132 err = alua_initialize(sdev, h); 1133 if (err != SCSI_DH_OK && err != SCSI_DH_DEV_OFFLINED) 1134 goto failed; 1135 1136 sdev->handler_data = h; 1137 return SCSI_DH_OK; 1138failed: 1139 kfree(h); 1140 return err; 1141} 1142 1143/* 1144 * alua_bus_detach - Detach device handler 1145 * @sdev: device to be detached from 1146 */ 1147static void alua_bus_detach(struct scsi_device *sdev) 1148{ 1149 struct alua_dh_data *h = sdev->handler_data; 1150 struct alua_port_group *pg; 1151 1152 spin_lock(&h->pg_lock); 1153 pg = rcu_dereference_protected(h->pg, lockdep_is_held(&h->pg_lock)); 1154 rcu_assign_pointer(h->pg, NULL); 1155 spin_unlock(&h->pg_lock); 1156 if (pg) { 1157 spin_lock_irq(&pg->lock); 1158 list_del_rcu(&h->node); 1159 spin_unlock_irq(&pg->lock); 1160 kref_put(&pg->kref, release_port_group); 1161 } 1162 sdev->handler_data = NULL; 1163 synchronize_rcu(); 1164 kfree(h); 1165} 1166 1167static struct scsi_device_handler alua_dh = { 1168 .name = ALUA_DH_NAME, 1169 .module = THIS_MODULE, 1170 .attach = alua_bus_attach, 1171 .detach = alua_bus_detach, 1172 .prep_fn = alua_prep_fn, 1173 .check_sense = alua_check_sense, 1174 .activate = alua_activate, 1175 .rescan = alua_rescan, 1176 .set_params = alua_set_params, 1177}; 1178 1179static int __init alua_init(void) 1180{ 1181 int r; 1182 1183 kaluad_wq = alloc_workqueue("kaluad", WQ_MEM_RECLAIM, 0); 1184 if (!kaluad_wq) 1185 return -ENOMEM; 1186 1187 r = scsi_register_device_handler(&alua_dh); 1188 if (r != 0) { 1189 printk(KERN_ERR "%s: Failed to register scsi device handler", 1190 ALUA_DH_NAME); 1191 destroy_workqueue(kaluad_wq); 1192 } 1193 return r; 1194} 1195 1196static void __exit alua_exit(void) 1197{ 1198 scsi_unregister_device_handler(&alua_dh); 1199 destroy_workqueue(kaluad_wq); 1200} 1201 1202module_init(alua_init); 1203module_exit(alua_exit); 1204 1205MODULE_DESCRIPTION("DM Multipath ALUA support"); 1206MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>"); 1207MODULE_LICENSE("GPL"); 1208MODULE_VERSION(ALUA_DH_VER); 1209