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 <asm/unaligned.h> 26 #include <scsi/scsi.h> 27 #include <scsi/scsi_proto.h> 28 #include <scsi/scsi_dbg.h> 29 #include <scsi/scsi_eh.h> 30 #include <scsi/scsi_dh.h> 31 32 #define ALUA_DH_NAME "alua" 33 #define ALUA_DH_VER "2.0" 34 35 #define TPGS_SUPPORT_NONE 0x00 36 #define TPGS_SUPPORT_OPTIMIZED 0x01 37 #define TPGS_SUPPORT_NONOPTIMIZED 0x02 38 #define TPGS_SUPPORT_STANDBY 0x04 39 #define TPGS_SUPPORT_UNAVAILABLE 0x08 40 #define TPGS_SUPPORT_LBA_DEPENDENT 0x10 41 #define TPGS_SUPPORT_OFFLINE 0x40 42 #define TPGS_SUPPORT_TRANSITION 0x80 43 44 #define RTPG_FMT_MASK 0x70 45 #define RTPG_FMT_EXT_HDR 0x10 46 47 #define TPGS_MODE_UNINITIALIZED -1 48 #define TPGS_MODE_NONE 0x0 49 #define TPGS_MODE_IMPLICIT 0x1 50 #define TPGS_MODE_EXPLICIT 0x2 51 52 #define ALUA_RTPG_SIZE 128 53 #define ALUA_FAILOVER_TIMEOUT 60 54 #define ALUA_FAILOVER_RETRIES 5 55 #define ALUA_RTPG_DELAY_MSECS 5 56 57 /* device handler flags */ 58 #define ALUA_OPTIMIZE_STPG 0x01 59 #define ALUA_RTPG_EXT_HDR_UNSUPP 0x02 60 #define ALUA_SYNC_STPG 0x04 61 /* State machine flags */ 62 #define ALUA_PG_RUN_RTPG 0x10 63 #define ALUA_PG_RUN_STPG 0x20 64 #define ALUA_PG_RUNNING 0x40 65 66 static uint optimize_stpg; 67 module_param(optimize_stpg, uint, S_IRUGO|S_IWUSR); 68 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."); 69 70 static LIST_HEAD(port_group_list); 71 static DEFINE_SPINLOCK(port_group_lock); 72 static struct workqueue_struct *kaluad_wq; 73 static struct workqueue_struct *kaluad_sync_wq; 74 75 struct alua_port_group { 76 struct kref kref; 77 struct rcu_head rcu; 78 struct list_head node; 79 struct list_head dh_list; 80 unsigned char device_id_str[256]; 81 int device_id_len; 82 int group_id; 83 int tpgs; 84 int state; 85 int pref; 86 unsigned flags; /* used for optimizing STPG */ 87 unsigned char transition_tmo; 88 unsigned long expiry; 89 unsigned long interval; 90 struct delayed_work rtpg_work; 91 spinlock_t lock; 92 struct list_head rtpg_list; 93 struct scsi_device *rtpg_sdev; 94 }; 95 96 struct alua_dh_data { 97 struct list_head node; 98 struct alua_port_group *pg; 99 int group_id; 100 spinlock_t pg_lock; 101 struct scsi_device *sdev; 102 int init_error; 103 struct mutex init_mutex; 104 }; 105 106 struct alua_queue_data { 107 struct list_head entry; 108 activate_complete callback_fn; 109 void *callback_data; 110 }; 111 112 #define ALUA_POLICY_SWITCH_CURRENT 0 113 #define ALUA_POLICY_SWITCH_ALL 1 114 115 static void alua_rtpg_work(struct work_struct *work); 116 static void alua_rtpg_queue(struct alua_port_group *pg, 117 struct scsi_device *sdev, 118 struct alua_queue_data *qdata, bool force); 119 static void alua_check(struct scsi_device *sdev, bool force); 120 121 static void release_port_group(struct kref *kref) 122 { 123 struct alua_port_group *pg; 124 125 pg = container_of(kref, struct alua_port_group, kref); 126 if (pg->rtpg_sdev) 127 flush_delayed_work(&pg->rtpg_work); 128 spin_lock(&port_group_lock); 129 list_del(&pg->node); 130 spin_unlock(&port_group_lock); 131 kfree_rcu(pg, rcu); 132 } 133 134 /* 135 * submit_rtpg - Issue a REPORT TARGET GROUP STATES command 136 * @sdev: sdev the command should be sent to 137 */ 138 static int submit_rtpg(struct scsi_device *sdev, unsigned char *buff, 139 int bufflen, struct scsi_sense_hdr *sshdr, int flags) 140 { 141 u8 cdb[COMMAND_SIZE(MAINTENANCE_IN)]; 142 int req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | 143 REQ_FAILFAST_DRIVER; 144 145 /* Prepare the command. */ 146 memset(cdb, 0x0, COMMAND_SIZE(MAINTENANCE_IN)); 147 cdb[0] = MAINTENANCE_IN; 148 if (!(flags & ALUA_RTPG_EXT_HDR_UNSUPP)) 149 cdb[1] = MI_REPORT_TARGET_PGS | MI_EXT_HDR_PARAM_FMT; 150 else 151 cdb[1] = MI_REPORT_TARGET_PGS; 152 put_unaligned_be32(bufflen, &cdb[6]); 153 154 return scsi_execute_req_flags(sdev, cdb, DMA_FROM_DEVICE, 155 buff, bufflen, sshdr, 156 ALUA_FAILOVER_TIMEOUT * HZ, 157 ALUA_FAILOVER_RETRIES, NULL, req_flags); 158 } 159 160 /* 161 * submit_stpg - Issue a SET TARGET PORT GROUP command 162 * 163 * Currently we're only setting the current target port group state 164 * to 'active/optimized' and let the array firmware figure out 165 * the states of the remaining groups. 166 */ 167 static int submit_stpg(struct scsi_device *sdev, int group_id, 168 struct scsi_sense_hdr *sshdr) 169 { 170 u8 cdb[COMMAND_SIZE(MAINTENANCE_OUT)]; 171 unsigned char stpg_data[8]; 172 int stpg_len = 8; 173 int req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | 174 REQ_FAILFAST_DRIVER; 175 176 /* Prepare the data buffer */ 177 memset(stpg_data, 0, stpg_len); 178 stpg_data[4] = SCSI_ACCESS_STATE_OPTIMAL; 179 put_unaligned_be16(group_id, &stpg_data[6]); 180 181 /* Prepare the command. */ 182 memset(cdb, 0x0, COMMAND_SIZE(MAINTENANCE_OUT)); 183 cdb[0] = MAINTENANCE_OUT; 184 cdb[1] = MO_SET_TARGET_PGS; 185 put_unaligned_be32(stpg_len, &cdb[6]); 186 187 return scsi_execute_req_flags(sdev, cdb, DMA_TO_DEVICE, 188 stpg_data, stpg_len, 189 sshdr, ALUA_FAILOVER_TIMEOUT * HZ, 190 ALUA_FAILOVER_RETRIES, NULL, req_flags); 191 } 192 193 struct alua_port_group *alua_find_get_pg(char *id_str, size_t id_size, 194 int group_id) 195 { 196 struct alua_port_group *pg; 197 198 list_for_each_entry(pg, &port_group_list, node) { 199 if (pg->group_id != group_id) 200 continue; 201 if (pg->device_id_len != id_size) 202 continue; 203 if (strncmp(pg->device_id_str, id_str, id_size)) 204 continue; 205 if (!kref_get_unless_zero(&pg->kref)) 206 continue; 207 return pg; 208 } 209 210 return NULL; 211 } 212 213 /* 214 * alua_alloc_pg - Allocate a new port_group structure 215 * @sdev: scsi device 216 * @h: alua device_handler data 217 * @group_id: port group id 218 * 219 * Allocate a new port_group structure for a given 220 * device. 221 */ 222 struct alua_port_group *alua_alloc_pg(struct scsi_device *sdev, 223 int group_id, int tpgs) 224 { 225 struct alua_port_group *pg, *tmp_pg; 226 227 pg = kzalloc(sizeof(struct alua_port_group), GFP_KERNEL); 228 if (!pg) 229 return ERR_PTR(-ENOMEM); 230 231 pg->device_id_len = scsi_vpd_lun_id(sdev, pg->device_id_str, 232 sizeof(pg->device_id_str)); 233 if (pg->device_id_len <= 0) { 234 /* 235 * Internal error: TPGS supported but no device 236 * identifcation found. Disable ALUA support. 237 */ 238 kfree(pg); 239 sdev_printk(KERN_INFO, sdev, 240 "%s: No device descriptors found\n", 241 ALUA_DH_NAME); 242 return ERR_PTR(-ENXIO); 243 } 244 pg->group_id = group_id; 245 pg->tpgs = tpgs; 246 pg->state = SCSI_ACCESS_STATE_OPTIMAL; 247 if (optimize_stpg) 248 pg->flags |= ALUA_OPTIMIZE_STPG; 249 kref_init(&pg->kref); 250 INIT_DELAYED_WORK(&pg->rtpg_work, alua_rtpg_work); 251 INIT_LIST_HEAD(&pg->rtpg_list); 252 INIT_LIST_HEAD(&pg->node); 253 INIT_LIST_HEAD(&pg->dh_list); 254 spin_lock_init(&pg->lock); 255 256 spin_lock(&port_group_lock); 257 tmp_pg = alua_find_get_pg(pg->device_id_str, pg->device_id_len, 258 group_id); 259 if (tmp_pg) { 260 spin_unlock(&port_group_lock); 261 kfree(pg); 262 return tmp_pg; 263 } 264 265 list_add(&pg->node, &port_group_list); 266 spin_unlock(&port_group_lock); 267 268 return pg; 269 } 270 271 /* 272 * alua_check_tpgs - Evaluate TPGS setting 273 * @sdev: device to be checked 274 * 275 * Examine the TPGS setting of the sdev to find out if ALUA 276 * is supported. 277 */ 278 static int alua_check_tpgs(struct scsi_device *sdev) 279 { 280 int tpgs = TPGS_MODE_NONE; 281 282 /* 283 * ALUA support for non-disk devices is fraught with 284 * difficulties, so disable it for now. 285 */ 286 if (sdev->type != TYPE_DISK) { 287 sdev_printk(KERN_INFO, sdev, 288 "%s: disable for non-disk devices\n", 289 ALUA_DH_NAME); 290 return tpgs; 291 } 292 293 tpgs = scsi_device_tpgs(sdev); 294 switch (tpgs) { 295 case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT: 296 sdev_printk(KERN_INFO, sdev, 297 "%s: supports implicit and explicit TPGS\n", 298 ALUA_DH_NAME); 299 break; 300 case TPGS_MODE_EXPLICIT: 301 sdev_printk(KERN_INFO, sdev, "%s: supports explicit TPGS\n", 302 ALUA_DH_NAME); 303 break; 304 case TPGS_MODE_IMPLICIT: 305 sdev_printk(KERN_INFO, sdev, "%s: supports implicit TPGS\n", 306 ALUA_DH_NAME); 307 break; 308 case TPGS_MODE_NONE: 309 sdev_printk(KERN_INFO, sdev, "%s: not supported\n", 310 ALUA_DH_NAME); 311 break; 312 default: 313 sdev_printk(KERN_INFO, sdev, 314 "%s: unsupported TPGS setting %d\n", 315 ALUA_DH_NAME, tpgs); 316 tpgs = TPGS_MODE_NONE; 317 break; 318 } 319 320 return tpgs; 321 } 322 323 /* 324 * alua_check_vpd - Evaluate INQUIRY vpd page 0x83 325 * @sdev: device to be checked 326 * 327 * Extract the relative target port and the target port group 328 * descriptor from the list of identificators. 329 */ 330 static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h, 331 int tpgs) 332 { 333 int rel_port = -1, group_id; 334 struct alua_port_group *pg, *old_pg = NULL; 335 bool pg_updated = false; 336 unsigned long flags; 337 338 group_id = scsi_vpd_tpg_id(sdev, &rel_port); 339 if (group_id < 0) { 340 /* 341 * Internal error; TPGS supported but required 342 * VPD identification descriptors not present. 343 * Disable ALUA support 344 */ 345 sdev_printk(KERN_INFO, sdev, 346 "%s: No target port descriptors found\n", 347 ALUA_DH_NAME); 348 return SCSI_DH_DEV_UNSUPP; 349 } 350 351 pg = alua_alloc_pg(sdev, group_id, tpgs); 352 if (IS_ERR(pg)) { 353 if (PTR_ERR(pg) == -ENOMEM) 354 return SCSI_DH_NOMEM; 355 return SCSI_DH_DEV_UNSUPP; 356 } 357 sdev_printk(KERN_INFO, sdev, 358 "%s: device %s port group %x rel port %x\n", 359 ALUA_DH_NAME, pg->device_id_str, group_id, rel_port); 360 361 /* Check for existing port group references */ 362 spin_lock(&h->pg_lock); 363 old_pg = h->pg; 364 if (old_pg != pg) { 365 /* port group has changed. Update to new port group */ 366 if (h->pg) { 367 spin_lock_irqsave(&old_pg->lock, flags); 368 list_del_rcu(&h->node); 369 spin_unlock_irqrestore(&old_pg->lock, flags); 370 } 371 rcu_assign_pointer(h->pg, pg); 372 pg_updated = true; 373 } 374 375 spin_lock_irqsave(&pg->lock, flags); 376 if (sdev->synchronous_alua) 377 pg->flags |= ALUA_SYNC_STPG; 378 if (pg_updated) 379 list_add_rcu(&h->node, &pg->dh_list); 380 spin_unlock_irqrestore(&pg->lock, flags); 381 382 alua_rtpg_queue(h->pg, sdev, NULL, true); 383 spin_unlock(&h->pg_lock); 384 385 if (old_pg) 386 kref_put(&old_pg->kref, release_port_group); 387 388 return SCSI_DH_OK; 389 } 390 391 static char print_alua_state(unsigned char state) 392 { 393 switch (state) { 394 case SCSI_ACCESS_STATE_OPTIMAL: 395 return 'A'; 396 case SCSI_ACCESS_STATE_ACTIVE: 397 return 'N'; 398 case SCSI_ACCESS_STATE_STANDBY: 399 return 'S'; 400 case SCSI_ACCESS_STATE_UNAVAILABLE: 401 return 'U'; 402 case SCSI_ACCESS_STATE_LBA: 403 return 'L'; 404 case SCSI_ACCESS_STATE_OFFLINE: 405 return 'O'; 406 case SCSI_ACCESS_STATE_TRANSITIONING: 407 return 'T'; 408 default: 409 return 'X'; 410 } 411 } 412 413 static int alua_check_sense(struct scsi_device *sdev, 414 struct scsi_sense_hdr *sense_hdr) 415 { 416 switch (sense_hdr->sense_key) { 417 case NOT_READY: 418 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a) { 419 /* 420 * LUN Not Accessible - ALUA state transition 421 */ 422 alua_check(sdev, false); 423 return NEEDS_RETRY; 424 } 425 break; 426 case UNIT_ATTENTION: 427 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00) { 428 /* 429 * Power On, Reset, or Bus Device Reset. 430 * Might have obscured a state transition, 431 * so schedule a recheck. 432 */ 433 alua_check(sdev, true); 434 return ADD_TO_MLQUEUE; 435 } 436 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x04) 437 /* 438 * Device internal reset 439 */ 440 return ADD_TO_MLQUEUE; 441 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x01) 442 /* 443 * Mode Parameters Changed 444 */ 445 return ADD_TO_MLQUEUE; 446 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) { 447 /* 448 * ALUA state changed 449 */ 450 alua_check(sdev, true); 451 return ADD_TO_MLQUEUE; 452 } 453 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) { 454 /* 455 * Implicit ALUA state transition failed 456 */ 457 alua_check(sdev, true); 458 return ADD_TO_MLQUEUE; 459 } 460 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x03) 461 /* 462 * Inquiry data has changed 463 */ 464 return ADD_TO_MLQUEUE; 465 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x0e) 466 /* 467 * REPORTED_LUNS_DATA_HAS_CHANGED is reported 468 * when switching controllers on targets like 469 * Intel Multi-Flex. We can just retry. 470 */ 471 return ADD_TO_MLQUEUE; 472 break; 473 } 474 475 return SCSI_RETURN_NOT_HANDLED; 476 } 477 478 /* 479 * alua_tur - Send a TEST UNIT READY 480 * @sdev: device to which the TEST UNIT READY command should be send 481 * 482 * Send a TEST UNIT READY to @sdev to figure out the device state 483 * Returns SCSI_DH_RETRY if the sense code is NOT READY/ALUA TRANSITIONING, 484 * SCSI_DH_OK if no error occurred, and SCSI_DH_IO otherwise. 485 */ 486 static int alua_tur(struct scsi_device *sdev) 487 { 488 struct scsi_sense_hdr sense_hdr; 489 int retval; 490 491 retval = scsi_test_unit_ready(sdev, ALUA_FAILOVER_TIMEOUT * HZ, 492 ALUA_FAILOVER_RETRIES, &sense_hdr); 493 if (sense_hdr.sense_key == NOT_READY && 494 sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a) 495 return SCSI_DH_RETRY; 496 else if (retval) 497 return SCSI_DH_IO; 498 else 499 return SCSI_DH_OK; 500 } 501 502 /* 503 * alua_rtpg - Evaluate REPORT TARGET GROUP STATES 504 * @sdev: the device to be evaluated. 505 * 506 * Evaluate the Target Port Group State. 507 * Returns SCSI_DH_DEV_OFFLINED if the path is 508 * found to be unusable. 509 */ 510 static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg) 511 { 512 struct scsi_sense_hdr sense_hdr; 513 struct alua_port_group *tmp_pg; 514 int len, k, off, valid_states = 0, bufflen = ALUA_RTPG_SIZE; 515 unsigned char *desc, *buff; 516 unsigned err, retval; 517 unsigned int tpg_desc_tbl_off; 518 unsigned char orig_transition_tmo; 519 unsigned long flags; 520 521 if (!pg->expiry) { 522 unsigned long transition_tmo = ALUA_FAILOVER_TIMEOUT * HZ; 523 524 if (pg->transition_tmo) 525 transition_tmo = pg->transition_tmo * HZ; 526 527 pg->expiry = round_jiffies_up(jiffies + transition_tmo); 528 } 529 530 buff = kzalloc(bufflen, GFP_KERNEL); 531 if (!buff) 532 return SCSI_DH_DEV_TEMP_BUSY; 533 534 retry: 535 retval = submit_rtpg(sdev, buff, bufflen, &sense_hdr, pg->flags); 536 537 if (retval) { 538 if (!scsi_sense_valid(&sense_hdr)) { 539 sdev_printk(KERN_INFO, sdev, 540 "%s: rtpg failed, result %d\n", 541 ALUA_DH_NAME, retval); 542 kfree(buff); 543 if (driver_byte(retval) == DRIVER_ERROR) 544 return SCSI_DH_DEV_TEMP_BUSY; 545 return SCSI_DH_IO; 546 } 547 548 /* 549 * submit_rtpg() has failed on existing arrays 550 * when requesting extended header info, and 551 * the array doesn't support extended headers, 552 * even though it shouldn't according to T10. 553 * The retry without rtpg_ext_hdr_req set 554 * handles this. 555 */ 556 if (!(pg->flags & ALUA_RTPG_EXT_HDR_UNSUPP) && 557 sense_hdr.sense_key == ILLEGAL_REQUEST && 558 sense_hdr.asc == 0x24 && sense_hdr.ascq == 0) { 559 pg->flags |= ALUA_RTPG_EXT_HDR_UNSUPP; 560 goto retry; 561 } 562 /* 563 * Retry on ALUA state transition or if any 564 * UNIT ATTENTION occurred. 565 */ 566 if (sense_hdr.sense_key == NOT_READY && 567 sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a) 568 err = SCSI_DH_RETRY; 569 else if (sense_hdr.sense_key == UNIT_ATTENTION) 570 err = SCSI_DH_RETRY; 571 if (err == SCSI_DH_RETRY && 572 pg->expiry != 0 && time_before(jiffies, pg->expiry)) { 573 sdev_printk(KERN_ERR, sdev, "%s: rtpg retry\n", 574 ALUA_DH_NAME); 575 scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr); 576 return err; 577 } 578 sdev_printk(KERN_ERR, sdev, "%s: rtpg failed\n", 579 ALUA_DH_NAME); 580 scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr); 581 kfree(buff); 582 pg->expiry = 0; 583 return SCSI_DH_IO; 584 } 585 586 len = get_unaligned_be32(&buff[0]) + 4; 587 588 if (len > bufflen) { 589 /* Resubmit with the correct length */ 590 kfree(buff); 591 bufflen = len; 592 buff = kmalloc(bufflen, GFP_KERNEL); 593 if (!buff) { 594 sdev_printk(KERN_WARNING, sdev, 595 "%s: kmalloc buffer failed\n",__func__); 596 /* Temporary failure, bypass */ 597 pg->expiry = 0; 598 return SCSI_DH_DEV_TEMP_BUSY; 599 } 600 goto retry; 601 } 602 603 orig_transition_tmo = pg->transition_tmo; 604 if ((buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR && buff[5] != 0) 605 pg->transition_tmo = buff[5]; 606 else 607 pg->transition_tmo = ALUA_FAILOVER_TIMEOUT; 608 609 if (orig_transition_tmo != pg->transition_tmo) { 610 sdev_printk(KERN_INFO, sdev, 611 "%s: transition timeout set to %d seconds\n", 612 ALUA_DH_NAME, pg->transition_tmo); 613 pg->expiry = jiffies + pg->transition_tmo * HZ; 614 } 615 616 if ((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, desc = buff + tpg_desc_tbl_off; 622 k < len; 623 k += off, desc += off) { 624 u16 group_id = get_unaligned_be16(&desc[2]); 625 626 spin_lock_irqsave(&port_group_lock, flags); 627 tmp_pg = alua_find_get_pg(pg->device_id_str, pg->device_id_len, 628 group_id); 629 spin_unlock_irqrestore(&port_group_lock, flags); 630 if (tmp_pg) { 631 if (spin_trylock_irqsave(&tmp_pg->lock, flags)) { 632 if ((tmp_pg == pg) || 633 !(tmp_pg->flags & ALUA_PG_RUNNING)) { 634 struct alua_dh_data *h; 635 636 tmp_pg->state = desc[0] & 0x0f; 637 tmp_pg->pref = desc[0] >> 7; 638 rcu_read_lock(); 639 list_for_each_entry_rcu(h, 640 &tmp_pg->dh_list, node) { 641 /* h->sdev should always be valid */ 642 BUG_ON(!h->sdev); 643 h->sdev->access_state = desc[0]; 644 } 645 rcu_read_unlock(); 646 } 647 if (tmp_pg == pg) 648 valid_states = desc[1]; 649 spin_unlock_irqrestore(&tmp_pg->lock, flags); 650 } 651 kref_put(&tmp_pg->kref, release_port_group); 652 } 653 off = 8 + (desc[7] * 4); 654 } 655 656 spin_lock_irqsave(&pg->lock, flags); 657 sdev_printk(KERN_INFO, sdev, 658 "%s: port group %02x state %c %s supports %c%c%c%c%c%c%c\n", 659 ALUA_DH_NAME, pg->group_id, print_alua_state(pg->state), 660 pg->pref ? "preferred" : "non-preferred", 661 valid_states&TPGS_SUPPORT_TRANSITION?'T':'t', 662 valid_states&TPGS_SUPPORT_OFFLINE?'O':'o', 663 valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l', 664 valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u', 665 valid_states&TPGS_SUPPORT_STANDBY?'S':'s', 666 valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n', 667 valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a'); 668 669 switch (pg->state) { 670 case SCSI_ACCESS_STATE_TRANSITIONING: 671 if (time_before(jiffies, pg->expiry)) { 672 /* State transition, retry */ 673 pg->interval = 2; 674 err = SCSI_DH_RETRY; 675 } else { 676 struct alua_dh_data *h; 677 678 /* Transitioning time exceeded, set port to standby */ 679 err = SCSI_DH_IO; 680 pg->state = SCSI_ACCESS_STATE_STANDBY; 681 pg->expiry = 0; 682 rcu_read_lock(); 683 list_for_each_entry_rcu(h, &pg->dh_list, node) { 684 BUG_ON(!h->sdev); 685 h->sdev->access_state = 686 (pg->state & SCSI_ACCESS_STATE_MASK); 687 if (pg->pref) 688 h->sdev->access_state |= 689 SCSI_ACCESS_STATE_PREFERRED; 690 } 691 rcu_read_unlock(); 692 } 693 break; 694 case SCSI_ACCESS_STATE_OFFLINE: 695 /* Path unusable */ 696 err = SCSI_DH_DEV_OFFLINED; 697 pg->expiry = 0; 698 break; 699 default: 700 /* Useable path if active */ 701 err = SCSI_DH_OK; 702 pg->expiry = 0; 703 break; 704 } 705 spin_unlock_irqrestore(&pg->lock, flags); 706 kfree(buff); 707 return err; 708 } 709 710 /* 711 * alua_stpg - Issue a SET TARGET PORT GROUP command 712 * 713 * Issue a SET TARGET PORT GROUP command and evaluate the 714 * response. Returns SCSI_DH_RETRY per default to trigger 715 * a re-evaluation of the target group state or SCSI_DH_OK 716 * if no further action needs to be taken. 717 */ 718 static unsigned alua_stpg(struct scsi_device *sdev, struct alua_port_group *pg) 719 { 720 int retval; 721 struct scsi_sense_hdr sense_hdr; 722 723 if (!(pg->tpgs & TPGS_MODE_EXPLICIT)) { 724 /* Only implicit ALUA supported, retry */ 725 return SCSI_DH_RETRY; 726 } 727 switch (pg->state) { 728 case SCSI_ACCESS_STATE_OPTIMAL: 729 return SCSI_DH_OK; 730 case SCSI_ACCESS_STATE_ACTIVE: 731 if ((pg->flags & ALUA_OPTIMIZE_STPG) && 732 !pg->pref && 733 (pg->tpgs & TPGS_MODE_IMPLICIT)) 734 return SCSI_DH_OK; 735 break; 736 case SCSI_ACCESS_STATE_STANDBY: 737 case SCSI_ACCESS_STATE_UNAVAILABLE: 738 break; 739 case SCSI_ACCESS_STATE_OFFLINE: 740 return SCSI_DH_IO; 741 case SCSI_ACCESS_STATE_TRANSITIONING: 742 break; 743 default: 744 sdev_printk(KERN_INFO, sdev, 745 "%s: stpg failed, unhandled TPGS state %d", 746 ALUA_DH_NAME, pg->state); 747 return SCSI_DH_NOSYS; 748 } 749 retval = submit_stpg(sdev, pg->group_id, &sense_hdr); 750 751 if (retval) { 752 if (!scsi_sense_valid(&sense_hdr)) { 753 sdev_printk(KERN_INFO, sdev, 754 "%s: stpg failed, result %d", 755 ALUA_DH_NAME, retval); 756 if (driver_byte(retval) == DRIVER_ERROR) 757 return SCSI_DH_DEV_TEMP_BUSY; 758 } else { 759 sdev_printk(KERN_INFO, sdev, "%s: stpg failed\n", 760 ALUA_DH_NAME); 761 scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr); 762 } 763 } 764 /* Retry RTPG */ 765 return SCSI_DH_RETRY; 766 } 767 768 static void alua_rtpg_work(struct work_struct *work) 769 { 770 struct alua_port_group *pg = 771 container_of(work, struct alua_port_group, rtpg_work.work); 772 struct scsi_device *sdev; 773 LIST_HEAD(qdata_list); 774 int err = SCSI_DH_OK; 775 struct alua_queue_data *qdata, *tmp; 776 unsigned long flags; 777 struct workqueue_struct *alua_wq = kaluad_wq; 778 779 spin_lock_irqsave(&pg->lock, flags); 780 sdev = pg->rtpg_sdev; 781 if (!sdev) { 782 WARN_ON(pg->flags & ALUA_PG_RUN_RTPG); 783 WARN_ON(pg->flags & ALUA_PG_RUN_STPG); 784 spin_unlock_irqrestore(&pg->lock, flags); 785 return; 786 } 787 if (pg->flags & ALUA_SYNC_STPG) 788 alua_wq = kaluad_sync_wq; 789 pg->flags |= ALUA_PG_RUNNING; 790 if (pg->flags & ALUA_PG_RUN_RTPG) { 791 int state = pg->state; 792 793 pg->flags &= ~ALUA_PG_RUN_RTPG; 794 spin_unlock_irqrestore(&pg->lock, flags); 795 if (state == SCSI_ACCESS_STATE_TRANSITIONING) { 796 if (alua_tur(sdev) == SCSI_DH_RETRY) { 797 spin_lock_irqsave(&pg->lock, flags); 798 pg->flags &= ~ALUA_PG_RUNNING; 799 pg->flags |= ALUA_PG_RUN_RTPG; 800 spin_unlock_irqrestore(&pg->lock, flags); 801 queue_delayed_work(alua_wq, &pg->rtpg_work, 802 pg->interval * HZ); 803 return; 804 } 805 /* Send RTPG on failure or if TUR indicates SUCCESS */ 806 } 807 err = alua_rtpg(sdev, pg); 808 spin_lock_irqsave(&pg->lock, flags); 809 if (err == SCSI_DH_RETRY || pg->flags & ALUA_PG_RUN_RTPG) { 810 pg->flags &= ~ALUA_PG_RUNNING; 811 pg->flags |= ALUA_PG_RUN_RTPG; 812 spin_unlock_irqrestore(&pg->lock, flags); 813 queue_delayed_work(alua_wq, &pg->rtpg_work, 814 pg->interval * HZ); 815 return; 816 } 817 if (err != SCSI_DH_OK) 818 pg->flags &= ~ALUA_PG_RUN_STPG; 819 } 820 if (pg->flags & ALUA_PG_RUN_STPG) { 821 pg->flags &= ~ALUA_PG_RUN_STPG; 822 spin_unlock_irqrestore(&pg->lock, flags); 823 err = alua_stpg(sdev, pg); 824 spin_lock_irqsave(&pg->lock, flags); 825 if (err == SCSI_DH_RETRY || pg->flags & ALUA_PG_RUN_RTPG) { 826 pg->flags |= ALUA_PG_RUN_RTPG; 827 pg->interval = 0; 828 pg->flags &= ~ALUA_PG_RUNNING; 829 spin_unlock_irqrestore(&pg->lock, flags); 830 queue_delayed_work(alua_wq, &pg->rtpg_work, 831 pg->interval * HZ); 832 return; 833 } 834 } 835 836 list_splice_init(&pg->rtpg_list, &qdata_list); 837 pg->rtpg_sdev = NULL; 838 spin_unlock_irqrestore(&pg->lock, flags); 839 840 list_for_each_entry_safe(qdata, tmp, &qdata_list, entry) { 841 list_del(&qdata->entry); 842 if (qdata->callback_fn) 843 qdata->callback_fn(qdata->callback_data, err); 844 kfree(qdata); 845 } 846 spin_lock_irqsave(&pg->lock, flags); 847 pg->flags &= ~ALUA_PG_RUNNING; 848 spin_unlock_irqrestore(&pg->lock, flags); 849 scsi_device_put(sdev); 850 kref_put(&pg->kref, release_port_group); 851 } 852 853 static void alua_rtpg_queue(struct alua_port_group *pg, 854 struct scsi_device *sdev, 855 struct alua_queue_data *qdata, bool force) 856 { 857 int start_queue = 0; 858 unsigned long flags; 859 struct workqueue_struct *alua_wq = kaluad_wq; 860 861 if (!pg) 862 return; 863 864 spin_lock_irqsave(&pg->lock, flags); 865 if (qdata) { 866 list_add_tail(&qdata->entry, &pg->rtpg_list); 867 pg->flags |= ALUA_PG_RUN_STPG; 868 force = true; 869 } 870 if (pg->rtpg_sdev == NULL) { 871 pg->interval = 0; 872 pg->flags |= ALUA_PG_RUN_RTPG; 873 kref_get(&pg->kref); 874 pg->rtpg_sdev = sdev; 875 scsi_device_get(sdev); 876 start_queue = 1; 877 } else if (!(pg->flags & ALUA_PG_RUN_RTPG) && force) { 878 pg->flags |= ALUA_PG_RUN_RTPG; 879 /* Do not queue if the worker is already running */ 880 if (!(pg->flags & ALUA_PG_RUNNING)) { 881 kref_get(&pg->kref); 882 start_queue = 1; 883 } 884 } 885 886 if (pg->flags & ALUA_SYNC_STPG) 887 alua_wq = kaluad_sync_wq; 888 spin_unlock_irqrestore(&pg->lock, flags); 889 890 if (start_queue && 891 !queue_delayed_work(alua_wq, &pg->rtpg_work, 892 msecs_to_jiffies(ALUA_RTPG_DELAY_MSECS))) { 893 scsi_device_put(sdev); 894 kref_put(&pg->kref, release_port_group); 895 } 896 } 897 898 /* 899 * alua_initialize - Initialize ALUA state 900 * @sdev: the device to be initialized 901 * 902 * For the prep_fn to work correctly we have 903 * to initialize the ALUA state for the device. 904 */ 905 static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h) 906 { 907 int err = SCSI_DH_DEV_UNSUPP, tpgs; 908 909 mutex_lock(&h->init_mutex); 910 tpgs = alua_check_tpgs(sdev); 911 if (tpgs != TPGS_MODE_NONE) 912 err = alua_check_vpd(sdev, h, tpgs); 913 h->init_error = err; 914 mutex_unlock(&h->init_mutex); 915 return err; 916 } 917 /* 918 * alua_set_params - set/unset the optimize flag 919 * @sdev: device on the path to be activated 920 * params - parameters in the following format 921 * "no_of_params\0param1\0param2\0param3\0...\0" 922 * For example, to set the flag pass the following parameters 923 * from multipath.conf 924 * hardware_handler "2 alua 1" 925 */ 926 static int alua_set_params(struct scsi_device *sdev, const char *params) 927 { 928 struct alua_dh_data *h = sdev->handler_data; 929 struct alua_port_group __rcu *pg = NULL; 930 unsigned int optimize = 0, argc; 931 const char *p = params; 932 int result = SCSI_DH_OK; 933 unsigned long flags; 934 935 if ((sscanf(params, "%u", &argc) != 1) || (argc != 1)) 936 return -EINVAL; 937 938 while (*p++) 939 ; 940 if ((sscanf(p, "%u", &optimize) != 1) || (optimize > 1)) 941 return -EINVAL; 942 943 rcu_read_lock(); 944 pg = rcu_dereference(h->pg); 945 if (!pg) { 946 rcu_read_unlock(); 947 return -ENXIO; 948 } 949 spin_lock_irqsave(&pg->lock, flags); 950 if (optimize) 951 pg->flags |= ALUA_OPTIMIZE_STPG; 952 else 953 pg->flags &= ~ALUA_OPTIMIZE_STPG; 954 spin_unlock_irqrestore(&pg->lock, flags); 955 rcu_read_unlock(); 956 957 return result; 958 } 959 960 /* 961 * alua_activate - activate a path 962 * @sdev: device on the path to be activated 963 * 964 * We're currently switching the port group to be activated only and 965 * let the array figure out the rest. 966 * There may be other arrays which require us to switch all port groups 967 * based on a certain policy. But until we actually encounter them it 968 * should be okay. 969 */ 970 static int alua_activate(struct scsi_device *sdev, 971 activate_complete fn, void *data) 972 { 973 struct alua_dh_data *h = sdev->handler_data; 974 int err = SCSI_DH_OK; 975 struct alua_queue_data *qdata; 976 struct alua_port_group __rcu *pg; 977 978 qdata = kzalloc(sizeof(*qdata), GFP_KERNEL); 979 if (!qdata) { 980 err = SCSI_DH_RES_TEMP_UNAVAIL; 981 goto out; 982 } 983 qdata->callback_fn = fn; 984 qdata->callback_data = data; 985 986 mutex_lock(&h->init_mutex); 987 rcu_read_lock(); 988 pg = rcu_dereference(h->pg); 989 if (!pg || !kref_get_unless_zero(&pg->kref)) { 990 rcu_read_unlock(); 991 kfree(qdata); 992 err = h->init_error; 993 mutex_unlock(&h->init_mutex); 994 goto out; 995 } 996 fn = NULL; 997 rcu_read_unlock(); 998 mutex_unlock(&h->init_mutex); 999 1000 alua_rtpg_queue(pg, sdev, qdata, true); 1001 kref_put(&pg->kref, release_port_group); 1002 out: 1003 if (fn) 1004 fn(data, err); 1005 return 0; 1006 } 1007 1008 /* 1009 * alua_check - check path status 1010 * @sdev: device on the path to be checked 1011 * 1012 * Check the device status 1013 */ 1014 static void alua_check(struct scsi_device *sdev, bool force) 1015 { 1016 struct alua_dh_data *h = sdev->handler_data; 1017 struct alua_port_group *pg; 1018 1019 rcu_read_lock(); 1020 pg = rcu_dereference(h->pg); 1021 if (!pg || !kref_get_unless_zero(&pg->kref)) { 1022 rcu_read_unlock(); 1023 return; 1024 } 1025 rcu_read_unlock(); 1026 1027 alua_rtpg_queue(pg, sdev, NULL, force); 1028 kref_put(&pg->kref, release_port_group); 1029 } 1030 1031 /* 1032 * alua_prep_fn - request callback 1033 * 1034 * Fail I/O to all paths not in state 1035 * active/optimized or active/non-optimized. 1036 */ 1037 static int alua_prep_fn(struct scsi_device *sdev, struct request *req) 1038 { 1039 struct alua_dh_data *h = sdev->handler_data; 1040 struct alua_port_group __rcu *pg; 1041 unsigned char state = SCSI_ACCESS_STATE_OPTIMAL; 1042 int ret = BLKPREP_OK; 1043 1044 rcu_read_lock(); 1045 pg = rcu_dereference(h->pg); 1046 if (pg) 1047 state = pg->state; 1048 rcu_read_unlock(); 1049 if (state == SCSI_ACCESS_STATE_TRANSITIONING) 1050 ret = BLKPREP_DEFER; 1051 else if (state != SCSI_ACCESS_STATE_OPTIMAL && 1052 state != SCSI_ACCESS_STATE_ACTIVE && 1053 state != SCSI_ACCESS_STATE_LBA) { 1054 ret = BLKPREP_KILL; 1055 req->cmd_flags |= REQ_QUIET; 1056 } 1057 return ret; 1058 1059 } 1060 1061 static void alua_rescan(struct scsi_device *sdev) 1062 { 1063 struct alua_dh_data *h = sdev->handler_data; 1064 1065 alua_initialize(sdev, h); 1066 } 1067 1068 /* 1069 * alua_bus_attach - Attach device handler 1070 * @sdev: device to be attached to 1071 */ 1072 static int alua_bus_attach(struct scsi_device *sdev) 1073 { 1074 struct alua_dh_data *h; 1075 int err, ret = -EINVAL; 1076 1077 h = kzalloc(sizeof(*h) , GFP_KERNEL); 1078 if (!h) 1079 return -ENOMEM; 1080 spin_lock_init(&h->pg_lock); 1081 rcu_assign_pointer(h->pg, NULL); 1082 h->init_error = SCSI_DH_OK; 1083 h->sdev = sdev; 1084 INIT_LIST_HEAD(&h->node); 1085 1086 mutex_init(&h->init_mutex); 1087 err = alua_initialize(sdev, h); 1088 if (err == SCSI_DH_NOMEM) 1089 ret = -ENOMEM; 1090 if (err != SCSI_DH_OK && err != SCSI_DH_DEV_OFFLINED) 1091 goto failed; 1092 1093 sdev->handler_data = h; 1094 return 0; 1095 failed: 1096 kfree(h); 1097 return ret; 1098 } 1099 1100 /* 1101 * alua_bus_detach - Detach device handler 1102 * @sdev: device to be detached from 1103 */ 1104 static void alua_bus_detach(struct scsi_device *sdev) 1105 { 1106 struct alua_dh_data *h = sdev->handler_data; 1107 struct alua_port_group *pg; 1108 1109 spin_lock(&h->pg_lock); 1110 pg = h->pg; 1111 rcu_assign_pointer(h->pg, NULL); 1112 h->sdev = NULL; 1113 spin_unlock(&h->pg_lock); 1114 if (pg) { 1115 spin_lock_irq(&pg->lock); 1116 list_del_rcu(&h->node); 1117 spin_unlock_irq(&pg->lock); 1118 kref_put(&pg->kref, release_port_group); 1119 } 1120 sdev->handler_data = NULL; 1121 kfree(h); 1122 } 1123 1124 static struct scsi_device_handler alua_dh = { 1125 .name = ALUA_DH_NAME, 1126 .module = THIS_MODULE, 1127 .attach = alua_bus_attach, 1128 .detach = alua_bus_detach, 1129 .prep_fn = alua_prep_fn, 1130 .check_sense = alua_check_sense, 1131 .activate = alua_activate, 1132 .rescan = alua_rescan, 1133 .set_params = alua_set_params, 1134 }; 1135 1136 static int __init alua_init(void) 1137 { 1138 int r; 1139 1140 kaluad_wq = alloc_workqueue("kaluad", WQ_MEM_RECLAIM, 0); 1141 if (!kaluad_wq) { 1142 /* Temporary failure, bypass */ 1143 return SCSI_DH_DEV_TEMP_BUSY; 1144 } 1145 kaluad_sync_wq = create_workqueue("kaluad_sync"); 1146 if (!kaluad_sync_wq) { 1147 destroy_workqueue(kaluad_wq); 1148 return SCSI_DH_DEV_TEMP_BUSY; 1149 } 1150 r = scsi_register_device_handler(&alua_dh); 1151 if (r != 0) { 1152 printk(KERN_ERR "%s: Failed to register scsi device handler", 1153 ALUA_DH_NAME); 1154 destroy_workqueue(kaluad_sync_wq); 1155 destroy_workqueue(kaluad_wq); 1156 } 1157 return r; 1158 } 1159 1160 static void __exit alua_exit(void) 1161 { 1162 scsi_unregister_device_handler(&alua_dh); 1163 destroy_workqueue(kaluad_sync_wq); 1164 destroy_workqueue(kaluad_wq); 1165 } 1166 1167 module_init(alua_init); 1168 module_exit(alua_exit); 1169 1170 MODULE_DESCRIPTION("DM Multipath ALUA support"); 1171 MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>"); 1172 MODULE_LICENSE("GPL"); 1173 MODULE_VERSION(ALUA_DH_VER); 1174