| 1 | /* |
| 2 | * Copyright (C) 2003 Sistina Software Limited. |
| 3 | * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved. |
| 4 | * |
| 5 | * This file is released under the GPL. |
| 6 | */ |
| 7 | |
| 8 | #include <linux/device-mapper.h> |
| 9 | |
| 10 | #include "dm-rq.h" |
| 11 | #include "dm-bio-record.h" |
| 12 | #include "dm-path-selector.h" |
| 13 | #include "dm-uevent.h" |
| 14 | |
| 15 | #include <linux/blkdev.h> |
| 16 | #include <linux/ctype.h> |
| 17 | #include <linux/init.h> |
| 18 | #include <linux/mempool.h> |
| 19 | #include <linux/module.h> |
| 20 | #include <linux/pagemap.h> |
| 21 | #include <linux/slab.h> |
| 22 | #include <linux/time.h> |
| 23 | #include <linux/timer.h> |
| 24 | #include <linux/workqueue.h> |
| 25 | #include <linux/delay.h> |
| 26 | #include <scsi/scsi_dh.h> |
| 27 | #include <linux/atomic.h> |
| 28 | #include <linux/blk-mq.h> |
| 29 | |
| 30 | #define DM_MSG_PREFIX "multipath" |
| 31 | #define DM_PG_INIT_DELAY_MSECS 2000 |
| 32 | #define DM_PG_INIT_DELAY_DEFAULT ((unsigned) -1) |
| 33 | #define QUEUE_IF_NO_PATH_TIMEOUT_DEFAULT 0 |
| 34 | |
| 35 | static unsigned long queue_if_no_path_timeout_secs = QUEUE_IF_NO_PATH_TIMEOUT_DEFAULT; |
| 36 | |
| 37 | /* Path properties */ |
| 38 | struct pgpath { |
| 39 | struct list_head list; |
| 40 | |
| 41 | struct priority_group *pg; /* Owning PG */ |
| 42 | unsigned fail_count; /* Cumulative failure count */ |
| 43 | |
| 44 | struct dm_path path; |
| 45 | struct delayed_work activate_path; |
| 46 | |
| 47 | bool is_active:1; /* Path status */ |
| 48 | }; |
| 49 | |
| 50 | #define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path) |
| 51 | |
| 52 | /* |
| 53 | * Paths are grouped into Priority Groups and numbered from 1 upwards. |
| 54 | * Each has a path selector which controls which path gets used. |
| 55 | */ |
| 56 | struct priority_group { |
| 57 | struct list_head list; |
| 58 | |
| 59 | struct multipath *m; /* Owning multipath instance */ |
| 60 | struct path_selector ps; |
| 61 | |
| 62 | unsigned pg_num; /* Reference number */ |
| 63 | unsigned nr_pgpaths; /* Number of paths in PG */ |
| 64 | struct list_head pgpaths; |
| 65 | |
| 66 | bool bypassed:1; /* Temporarily bypass this PG? */ |
| 67 | }; |
| 68 | |
| 69 | /* Multipath context */ |
| 70 | struct multipath { |
| 71 | unsigned long flags; /* Multipath state flags */ |
| 72 | |
| 73 | spinlock_t lock; |
| 74 | enum dm_queue_mode queue_mode; |
| 75 | |
| 76 | struct pgpath *current_pgpath; |
| 77 | struct priority_group *current_pg; |
| 78 | struct priority_group *next_pg; /* Switch to this PG if set */ |
| 79 | |
| 80 | atomic_t nr_valid_paths; /* Total number of usable paths */ |
| 81 | unsigned nr_priority_groups; |
| 82 | struct list_head priority_groups; |
| 83 | |
| 84 | const char *hw_handler_name; |
| 85 | char *hw_handler_params; |
| 86 | wait_queue_head_t pg_init_wait; /* Wait for pg_init completion */ |
| 87 | unsigned pg_init_retries; /* Number of times to retry pg_init */ |
| 88 | unsigned pg_init_delay_msecs; /* Number of msecs before pg_init retry */ |
| 89 | atomic_t pg_init_in_progress; /* Only one pg_init allowed at once */ |
| 90 | atomic_t pg_init_count; /* Number of times pg_init called */ |
| 91 | |
| 92 | struct mutex work_mutex; |
| 93 | struct work_struct trigger_event; |
| 94 | struct dm_target *ti; |
| 95 | |
| 96 | struct work_struct process_queued_bios; |
| 97 | struct bio_list queued_bios; |
| 98 | |
| 99 | struct timer_list nopath_timer; /* Timeout for queue_if_no_path */ |
| 100 | }; |
| 101 | |
| 102 | /* |
| 103 | * Context information attached to each io we process. |
| 104 | */ |
| 105 | struct dm_mpath_io { |
| 106 | struct pgpath *pgpath; |
| 107 | size_t nr_bytes; |
| 108 | }; |
| 109 | |
| 110 | typedef int (*action_fn) (struct pgpath *pgpath); |
| 111 | |
| 112 | static struct workqueue_struct *kmultipathd, *kmpath_handlerd; |
| 113 | static void trigger_event(struct work_struct *work); |
| 114 | static void activate_or_offline_path(struct pgpath *pgpath); |
| 115 | static void activate_path_work(struct work_struct *work); |
| 116 | static void process_queued_bios(struct work_struct *work); |
| 117 | static void queue_if_no_path_timeout_work(struct timer_list *t); |
| 118 | |
| 119 | /*----------------------------------------------- |
| 120 | * Multipath state flags. |
| 121 | *-----------------------------------------------*/ |
| 122 | |
| 123 | #define MPATHF_QUEUE_IO 0 /* Must we queue all I/O? */ |
| 124 | #define MPATHF_QUEUE_IF_NO_PATH 1 /* Queue I/O if last path fails? */ |
| 125 | #define MPATHF_SAVED_QUEUE_IF_NO_PATH 2 /* Saved state during suspension */ |
| 126 | #define MPATHF_RETAIN_ATTACHED_HW_HANDLER 3 /* If there's already a hw_handler present, don't change it. */ |
| 127 | #define MPATHF_PG_INIT_DISABLED 4 /* pg_init is not currently allowed */ |
| 128 | #define MPATHF_PG_INIT_REQUIRED 5 /* pg_init needs calling? */ |
| 129 | #define MPATHF_PG_INIT_DELAY_RETRY 6 /* Delay pg_init retry? */ |
| 130 | |
| 131 | static bool mpath_double_check_test_bit(int MPATHF_bit, struct multipath *m) |
| 132 | { |
| 133 | bool r = test_bit(MPATHF_bit, &m->flags); |
| 134 | |
| 135 | if (r) { |
| 136 | unsigned long flags; |
| 137 | spin_lock_irqsave(&m->lock, flags); |
| 138 | r = test_bit(MPATHF_bit, &m->flags); |
| 139 | spin_unlock_irqrestore(&m->lock, flags); |
| 140 | } |
| 141 | |
| 142 | return r; |
| 143 | } |
| 144 | |
| 145 | /*----------------------------------------------- |
| 146 | * Allocation routines |
| 147 | *-----------------------------------------------*/ |
| 148 | |
| 149 | static struct pgpath *alloc_pgpath(void) |
| 150 | { |
| 151 | struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL); |
| 152 | |
| 153 | if (!pgpath) |
| 154 | return NULL; |
| 155 | |
| 156 | pgpath->is_active = true; |
| 157 | |
| 158 | return pgpath; |
| 159 | } |
| 160 | |
| 161 | static void free_pgpath(struct pgpath *pgpath) |
| 162 | { |
| 163 | kfree(pgpath); |
| 164 | } |
| 165 | |
| 166 | static struct priority_group *alloc_priority_group(void) |
| 167 | { |
| 168 | struct priority_group *pg; |
| 169 | |
| 170 | pg = kzalloc(sizeof(*pg), GFP_KERNEL); |
| 171 | |
| 172 | if (pg) |
| 173 | INIT_LIST_HEAD(&pg->pgpaths); |
| 174 | |
| 175 | return pg; |
| 176 | } |
| 177 | |
| 178 | static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti) |
| 179 | { |
| 180 | struct pgpath *pgpath, *tmp; |
| 181 | |
| 182 | list_for_each_entry_safe(pgpath, tmp, pgpaths, list) { |
| 183 | list_del(&pgpath->list); |
| 184 | dm_put_device(ti, pgpath->path.dev); |
| 185 | free_pgpath(pgpath); |
| 186 | } |
| 187 | } |
| 188 | |
| 189 | static void free_priority_group(struct priority_group *pg, |
| 190 | struct dm_target *ti) |
| 191 | { |
| 192 | struct path_selector *ps = &pg->ps; |
| 193 | |
| 194 | if (ps->type) { |
| 195 | ps->type->destroy(ps); |
| 196 | dm_put_path_selector(ps->type); |
| 197 | } |
| 198 | |
| 199 | free_pgpaths(&pg->pgpaths, ti); |
| 200 | kfree(pg); |
| 201 | } |
| 202 | |
| 203 | static struct multipath *alloc_multipath(struct dm_target *ti) |
| 204 | { |
| 205 | struct multipath *m; |
| 206 | |
| 207 | m = kzalloc(sizeof(*m), GFP_KERNEL); |
| 208 | if (m) { |
| 209 | INIT_LIST_HEAD(&m->priority_groups); |
| 210 | spin_lock_init(&m->lock); |
| 211 | atomic_set(&m->nr_valid_paths, 0); |
| 212 | INIT_WORK(&m->trigger_event, trigger_event); |
| 213 | mutex_init(&m->work_mutex); |
| 214 | |
| 215 | m->queue_mode = DM_TYPE_NONE; |
| 216 | |
| 217 | m->ti = ti; |
| 218 | ti->private = m; |
| 219 | |
| 220 | timer_setup(&m->nopath_timer, queue_if_no_path_timeout_work, 0); |
| 221 | } |
| 222 | |
| 223 | return m; |
| 224 | } |
| 225 | |
| 226 | static int alloc_multipath_stage2(struct dm_target *ti, struct multipath *m) |
| 227 | { |
| 228 | if (m->queue_mode == DM_TYPE_NONE) { |
| 229 | m->queue_mode = DM_TYPE_REQUEST_BASED; |
| 230 | } else if (m->queue_mode == DM_TYPE_BIO_BASED) { |
| 231 | INIT_WORK(&m->process_queued_bios, process_queued_bios); |
| 232 | /* |
| 233 | * bio-based doesn't support any direct scsi_dh management; |
| 234 | * it just discovers if a scsi_dh is attached. |
| 235 | */ |
| 236 | set_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags); |
| 237 | } |
| 238 | |
| 239 | dm_table_set_type(ti->table, m->queue_mode); |
| 240 | |
| 241 | /* |
| 242 | * Init fields that are only used when a scsi_dh is attached |
| 243 | * - must do this unconditionally (really doesn't hurt non-SCSI uses) |
| 244 | */ |
| 245 | set_bit(MPATHF_QUEUE_IO, &m->flags); |
| 246 | atomic_set(&m->pg_init_in_progress, 0); |
| 247 | atomic_set(&m->pg_init_count, 0); |
| 248 | m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT; |
| 249 | init_waitqueue_head(&m->pg_init_wait); |
| 250 | |
| 251 | return 0; |
| 252 | } |
| 253 | |
| 254 | static void free_multipath(struct multipath *m) |
| 255 | { |
| 256 | struct priority_group *pg, *tmp; |
| 257 | |
| 258 | list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) { |
| 259 | list_del(&pg->list); |
| 260 | free_priority_group(pg, m->ti); |
| 261 | } |
| 262 | |
| 263 | kfree(m->hw_handler_name); |
| 264 | kfree(m->hw_handler_params); |
| 265 | mutex_destroy(&m->work_mutex); |
| 266 | kfree(m); |
| 267 | } |
| 268 | |
| 269 | static struct dm_mpath_io *get_mpio(union map_info *info) |
| 270 | { |
| 271 | return info->ptr; |
| 272 | } |
| 273 | |
| 274 | static size_t multipath_per_bio_data_size(void) |
| 275 | { |
| 276 | return sizeof(struct dm_mpath_io) + sizeof(struct dm_bio_details); |
| 277 | } |
| 278 | |
| 279 | static struct dm_mpath_io *get_mpio_from_bio(struct bio *bio) |
| 280 | { |
| 281 | return dm_per_bio_data(bio, multipath_per_bio_data_size()); |
| 282 | } |
| 283 | |
| 284 | static struct dm_bio_details *get_bio_details_from_mpio(struct dm_mpath_io *mpio) |
| 285 | { |
| 286 | /* dm_bio_details is immediately after the dm_mpath_io in bio's per-bio-data */ |
| 287 | void *bio_details = mpio + 1; |
| 288 | return bio_details; |
| 289 | } |
| 290 | |
| 291 | static void multipath_init_per_bio_data(struct bio *bio, struct dm_mpath_io **mpio_p) |
| 292 | { |
| 293 | struct dm_mpath_io *mpio = get_mpio_from_bio(bio); |
| 294 | struct dm_bio_details *bio_details = get_bio_details_from_mpio(mpio); |
| 295 | |
| 296 | mpio->nr_bytes = bio->bi_iter.bi_size; |
| 297 | mpio->pgpath = NULL; |
| 298 | *mpio_p = mpio; |
| 299 | |
| 300 | dm_bio_record(bio_details, bio); |
| 301 | } |
| 302 | |
| 303 | /*----------------------------------------------- |
| 304 | * Path selection |
| 305 | *-----------------------------------------------*/ |
| 306 | |
| 307 | static int __pg_init_all_paths(struct multipath *m) |
| 308 | { |
| 309 | struct pgpath *pgpath; |
| 310 | unsigned long pg_init_delay = 0; |
| 311 | |
| 312 | lockdep_assert_held(&m->lock); |
| 313 | |
| 314 | if (atomic_read(&m->pg_init_in_progress) || test_bit(MPATHF_PG_INIT_DISABLED, &m->flags)) |
| 315 | return 0; |
| 316 | |
| 317 | atomic_inc(&m->pg_init_count); |
| 318 | clear_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); |
| 319 | |
| 320 | /* Check here to reset pg_init_required */ |
| 321 | if (!m->current_pg) |
| 322 | return 0; |
| 323 | |
| 324 | if (test_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags)) |
| 325 | pg_init_delay = msecs_to_jiffies(m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT ? |
| 326 | m->pg_init_delay_msecs : DM_PG_INIT_DELAY_MSECS); |
| 327 | list_for_each_entry(pgpath, &m->current_pg->pgpaths, list) { |
| 328 | /* Skip failed paths */ |
| 329 | if (!pgpath->is_active) |
| 330 | continue; |
| 331 | if (queue_delayed_work(kmpath_handlerd, &pgpath->activate_path, |
| 332 | pg_init_delay)) |
| 333 | atomic_inc(&m->pg_init_in_progress); |
| 334 | } |
| 335 | return atomic_read(&m->pg_init_in_progress); |
| 336 | } |
| 337 | |
| 338 | static int pg_init_all_paths(struct multipath *m) |
| 339 | { |
| 340 | int ret; |
| 341 | unsigned long flags; |
| 342 | |
| 343 | spin_lock_irqsave(&m->lock, flags); |
| 344 | ret = __pg_init_all_paths(m); |
| 345 | spin_unlock_irqrestore(&m->lock, flags); |
| 346 | |
| 347 | return ret; |
| 348 | } |
| 349 | |
| 350 | static void __switch_pg(struct multipath *m, struct priority_group *pg) |
| 351 | { |
| 352 | lockdep_assert_held(&m->lock); |
| 353 | |
| 354 | m->current_pg = pg; |
| 355 | |
| 356 | /* Must we initialise the PG first, and queue I/O till it's ready? */ |
| 357 | if (m->hw_handler_name) { |
| 358 | set_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); |
| 359 | set_bit(MPATHF_QUEUE_IO, &m->flags); |
| 360 | } else { |
| 361 | clear_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); |
| 362 | clear_bit(MPATHF_QUEUE_IO, &m->flags); |
| 363 | } |
| 364 | |
| 365 | atomic_set(&m->pg_init_count, 0); |
| 366 | } |
| 367 | |
| 368 | static struct pgpath *choose_path_in_pg(struct multipath *m, |
| 369 | struct priority_group *pg, |
| 370 | size_t nr_bytes) |
| 371 | { |
| 372 | unsigned long flags; |
| 373 | struct dm_path *path; |
| 374 | struct pgpath *pgpath; |
| 375 | |
| 376 | path = pg->ps.type->select_path(&pg->ps, nr_bytes); |
| 377 | if (!path) |
| 378 | return ERR_PTR(-ENXIO); |
| 379 | |
| 380 | pgpath = path_to_pgpath(path); |
| 381 | |
| 382 | if (unlikely(READ_ONCE(m->current_pg) != pg)) { |
| 383 | /* Only update current_pgpath if pg changed */ |
| 384 | spin_lock_irqsave(&m->lock, flags); |
| 385 | m->current_pgpath = pgpath; |
| 386 | __switch_pg(m, pg); |
| 387 | spin_unlock_irqrestore(&m->lock, flags); |
| 388 | } |
| 389 | |
| 390 | return pgpath; |
| 391 | } |
| 392 | |
| 393 | static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes) |
| 394 | { |
| 395 | unsigned long flags; |
| 396 | struct priority_group *pg; |
| 397 | struct pgpath *pgpath; |
| 398 | unsigned bypassed = 1; |
| 399 | |
| 400 | if (!atomic_read(&m->nr_valid_paths)) { |
| 401 | spin_lock_irqsave(&m->lock, flags); |
| 402 | clear_bit(MPATHF_QUEUE_IO, &m->flags); |
| 403 | spin_unlock_irqrestore(&m->lock, flags); |
| 404 | goto failed; |
| 405 | } |
| 406 | |
| 407 | /* Were we instructed to switch PG? */ |
| 408 | if (READ_ONCE(m->next_pg)) { |
| 409 | spin_lock_irqsave(&m->lock, flags); |
| 410 | pg = m->next_pg; |
| 411 | if (!pg) { |
| 412 | spin_unlock_irqrestore(&m->lock, flags); |
| 413 | goto check_current_pg; |
| 414 | } |
| 415 | m->next_pg = NULL; |
| 416 | spin_unlock_irqrestore(&m->lock, flags); |
| 417 | pgpath = choose_path_in_pg(m, pg, nr_bytes); |
| 418 | if (!IS_ERR_OR_NULL(pgpath)) |
| 419 | return pgpath; |
| 420 | } |
| 421 | |
| 422 | /* Don't change PG until it has no remaining paths */ |
| 423 | check_current_pg: |
| 424 | pg = READ_ONCE(m->current_pg); |
| 425 | if (pg) { |
| 426 | pgpath = choose_path_in_pg(m, pg, nr_bytes); |
| 427 | if (!IS_ERR_OR_NULL(pgpath)) |
| 428 | return pgpath; |
| 429 | } |
| 430 | |
| 431 | /* |
| 432 | * Loop through priority groups until we find a valid path. |
| 433 | * First time we skip PGs marked 'bypassed'. |
| 434 | * Second time we only try the ones we skipped, but set |
| 435 | * pg_init_delay_retry so we do not hammer controllers. |
| 436 | */ |
| 437 | do { |
| 438 | list_for_each_entry(pg, &m->priority_groups, list) { |
| 439 | if (pg->bypassed == !!bypassed) |
| 440 | continue; |
| 441 | pgpath = choose_path_in_pg(m, pg, nr_bytes); |
| 442 | if (!IS_ERR_OR_NULL(pgpath)) { |
| 443 | if (!bypassed) { |
| 444 | spin_lock_irqsave(&m->lock, flags); |
| 445 | set_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags); |
| 446 | spin_unlock_irqrestore(&m->lock, flags); |
| 447 | } |
| 448 | return pgpath; |
| 449 | } |
| 450 | } |
| 451 | } while (bypassed--); |
| 452 | |
| 453 | failed: |
| 454 | spin_lock_irqsave(&m->lock, flags); |
| 455 | m->current_pgpath = NULL; |
| 456 | m->current_pg = NULL; |
| 457 | spin_unlock_irqrestore(&m->lock, flags); |
| 458 | |
| 459 | return NULL; |
| 460 | } |
| 461 | |
| 462 | /* |
| 463 | * dm_report_EIO() is a macro instead of a function to make pr_debug_ratelimited() |
| 464 | * report the function name and line number of the function from which |
| 465 | * it has been invoked. |
| 466 | */ |
| 467 | #define dm_report_EIO(m) \ |
| 468 | do { \ |
| 469 | struct mapped_device *md = dm_table_get_md((m)->ti->table); \ |
| 470 | \ |
| 471 | DMDEBUG_LIMIT("%s: returning EIO; QIFNP = %d; SQIFNP = %d; DNFS = %d", \ |
| 472 | dm_device_name(md), \ |
| 473 | test_bit(MPATHF_QUEUE_IF_NO_PATH, &(m)->flags), \ |
| 474 | test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &(m)->flags), \ |
| 475 | dm_noflush_suspending((m)->ti)); \ |
| 476 | } while (0) |
| 477 | |
| 478 | /* |
| 479 | * Check whether bios must be queued in the device-mapper core rather |
| 480 | * than here in the target. |
| 481 | */ |
| 482 | static bool __must_push_back(struct multipath *m) |
| 483 | { |
| 484 | return dm_noflush_suspending(m->ti); |
| 485 | } |
| 486 | |
| 487 | static bool must_push_back_rq(struct multipath *m) |
| 488 | { |
| 489 | unsigned long flags; |
| 490 | bool ret; |
| 491 | |
| 492 | spin_lock_irqsave(&m->lock, flags); |
| 493 | ret = (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) || __must_push_back(m)); |
| 494 | spin_unlock_irqrestore(&m->lock, flags); |
| 495 | |
| 496 | return ret; |
| 497 | } |
| 498 | |
| 499 | /* |
| 500 | * Map cloned requests (request-based multipath) |
| 501 | */ |
| 502 | static int multipath_clone_and_map(struct dm_target *ti, struct request *rq, |
| 503 | union map_info *map_context, |
| 504 | struct request **__clone) |
| 505 | { |
| 506 | struct multipath *m = ti->private; |
| 507 | size_t nr_bytes = blk_rq_bytes(rq); |
| 508 | struct pgpath *pgpath; |
| 509 | struct block_device *bdev; |
| 510 | struct dm_mpath_io *mpio = get_mpio(map_context); |
| 511 | struct request_queue *q; |
| 512 | struct request *clone; |
| 513 | |
| 514 | /* Do we need to select a new pgpath? */ |
| 515 | pgpath = READ_ONCE(m->current_pgpath); |
| 516 | if (!pgpath || !mpath_double_check_test_bit(MPATHF_QUEUE_IO, m)) |
| 517 | pgpath = choose_pgpath(m, nr_bytes); |
| 518 | |
| 519 | if (!pgpath) { |
| 520 | if (must_push_back_rq(m)) |
| 521 | return DM_MAPIO_DELAY_REQUEUE; |
| 522 | dm_report_EIO(m); /* Failed */ |
| 523 | return DM_MAPIO_KILL; |
| 524 | } else if (mpath_double_check_test_bit(MPATHF_QUEUE_IO, m) || |
| 525 | mpath_double_check_test_bit(MPATHF_PG_INIT_REQUIRED, m)) { |
| 526 | pg_init_all_paths(m); |
| 527 | return DM_MAPIO_DELAY_REQUEUE; |
| 528 | } |
| 529 | |
| 530 | mpio->pgpath = pgpath; |
| 531 | mpio->nr_bytes = nr_bytes; |
| 532 | |
| 533 | bdev = pgpath->path.dev->bdev; |
| 534 | q = bdev_get_queue(bdev); |
| 535 | clone = blk_get_request(q, rq->cmd_flags | REQ_NOMERGE, |
| 536 | BLK_MQ_REQ_NOWAIT); |
| 537 | if (IS_ERR(clone)) { |
| 538 | /* EBUSY, ENODEV or EWOULDBLOCK: requeue */ |
| 539 | if (blk_queue_dying(q)) { |
| 540 | atomic_inc(&m->pg_init_in_progress); |
| 541 | activate_or_offline_path(pgpath); |
| 542 | return DM_MAPIO_DELAY_REQUEUE; |
| 543 | } |
| 544 | |
| 545 | /* |
| 546 | * blk-mq's SCHED_RESTART can cover this requeue, so we |
| 547 | * needn't deal with it by DELAY_REQUEUE. More importantly, |
| 548 | * we have to return DM_MAPIO_REQUEUE so that blk-mq can |
| 549 | * get the queue busy feedback (via BLK_STS_RESOURCE), |
| 550 | * otherwise I/O merging can suffer. |
| 551 | */ |
| 552 | return DM_MAPIO_REQUEUE; |
| 553 | } |
| 554 | clone->bio = clone->biotail = NULL; |
| 555 | clone->rq_disk = bdev->bd_disk; |
| 556 | clone->cmd_flags |= REQ_FAILFAST_TRANSPORT; |
| 557 | *__clone = clone; |
| 558 | |
| 559 | if (pgpath->pg->ps.type->start_io) |
| 560 | pgpath->pg->ps.type->start_io(&pgpath->pg->ps, |
| 561 | &pgpath->path, |
| 562 | nr_bytes); |
| 563 | return DM_MAPIO_REMAPPED; |
| 564 | } |
| 565 | |
| 566 | static void multipath_release_clone(struct request *clone, |
| 567 | union map_info *map_context) |
| 568 | { |
| 569 | if (unlikely(map_context)) { |
| 570 | /* |
| 571 | * non-NULL map_context means caller is still map |
| 572 | * method; must undo multipath_clone_and_map() |
| 573 | */ |
| 574 | struct dm_mpath_io *mpio = get_mpio(map_context); |
| 575 | struct pgpath *pgpath = mpio->pgpath; |
| 576 | |
| 577 | if (pgpath && pgpath->pg->ps.type->end_io) |
| 578 | pgpath->pg->ps.type->end_io(&pgpath->pg->ps, |
| 579 | &pgpath->path, |
| 580 | mpio->nr_bytes, |
| 581 | clone->io_start_time_ns); |
| 582 | } |
| 583 | |
| 584 | blk_put_request(clone); |
| 585 | } |
| 586 | |
| 587 | /* |
| 588 | * Map cloned bios (bio-based multipath) |
| 589 | */ |
| 590 | |
| 591 | static void __multipath_queue_bio(struct multipath *m, struct bio *bio) |
| 592 | { |
| 593 | /* Queue for the daemon to resubmit */ |
| 594 | bio_list_add(&m->queued_bios, bio); |
| 595 | if (!test_bit(MPATHF_QUEUE_IO, &m->flags)) |
| 596 | queue_work(kmultipathd, &m->process_queued_bios); |
| 597 | } |
| 598 | |
| 599 | static void multipath_queue_bio(struct multipath *m, struct bio *bio) |
| 600 | { |
| 601 | unsigned long flags; |
| 602 | |
| 603 | spin_lock_irqsave(&m->lock, flags); |
| 604 | __multipath_queue_bio(m, bio); |
| 605 | spin_unlock_irqrestore(&m->lock, flags); |
| 606 | } |
| 607 | |
| 608 | static struct pgpath *__map_bio(struct multipath *m, struct bio *bio) |
| 609 | { |
| 610 | struct pgpath *pgpath; |
| 611 | unsigned long flags; |
| 612 | |
| 613 | /* Do we need to select a new pgpath? */ |
| 614 | pgpath = READ_ONCE(m->current_pgpath); |
| 615 | if (!pgpath || !mpath_double_check_test_bit(MPATHF_QUEUE_IO, m)) |
| 616 | pgpath = choose_pgpath(m, bio->bi_iter.bi_size); |
| 617 | |
| 618 | if (!pgpath) { |
| 619 | spin_lock_irqsave(&m->lock, flags); |
| 620 | if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) { |
| 621 | __multipath_queue_bio(m, bio); |
| 622 | pgpath = ERR_PTR(-EAGAIN); |
| 623 | } |
| 624 | spin_unlock_irqrestore(&m->lock, flags); |
| 625 | |
| 626 | } else if (mpath_double_check_test_bit(MPATHF_QUEUE_IO, m) || |
| 627 | mpath_double_check_test_bit(MPATHF_PG_INIT_REQUIRED, m)) { |
| 628 | multipath_queue_bio(m, bio); |
| 629 | pg_init_all_paths(m); |
| 630 | return ERR_PTR(-EAGAIN); |
| 631 | } |
| 632 | |
| 633 | return pgpath; |
| 634 | } |
| 635 | |
| 636 | static int __multipath_map_bio(struct multipath *m, struct bio *bio, |
| 637 | struct dm_mpath_io *mpio) |
| 638 | { |
| 639 | struct pgpath *pgpath = __map_bio(m, bio); |
| 640 | |
| 641 | if (IS_ERR(pgpath)) |
| 642 | return DM_MAPIO_SUBMITTED; |
| 643 | |
| 644 | if (!pgpath) { |
| 645 | if (__must_push_back(m)) |
| 646 | return DM_MAPIO_REQUEUE; |
| 647 | dm_report_EIO(m); |
| 648 | return DM_MAPIO_KILL; |
| 649 | } |
| 650 | |
| 651 | mpio->pgpath = pgpath; |
| 652 | |
| 653 | bio->bi_status = 0; |
| 654 | bio_set_dev(bio, pgpath->path.dev->bdev); |
| 655 | bio->bi_opf |= REQ_FAILFAST_TRANSPORT; |
| 656 | |
| 657 | if (pgpath->pg->ps.type->start_io) |
| 658 | pgpath->pg->ps.type->start_io(&pgpath->pg->ps, |
| 659 | &pgpath->path, |
| 660 | mpio->nr_bytes); |
| 661 | return DM_MAPIO_REMAPPED; |
| 662 | } |
| 663 | |
| 664 | static int multipath_map_bio(struct dm_target *ti, struct bio *bio) |
| 665 | { |
| 666 | struct multipath *m = ti->private; |
| 667 | struct dm_mpath_io *mpio = NULL; |
| 668 | |
| 669 | multipath_init_per_bio_data(bio, &mpio); |
| 670 | return __multipath_map_bio(m, bio, mpio); |
| 671 | } |
| 672 | |
| 673 | static void process_queued_io_list(struct multipath *m) |
| 674 | { |
| 675 | if (m->queue_mode == DM_TYPE_REQUEST_BASED) |
| 676 | dm_mq_kick_requeue_list(dm_table_get_md(m->ti->table)); |
| 677 | else if (m->queue_mode == DM_TYPE_BIO_BASED) |
| 678 | queue_work(kmultipathd, &m->process_queued_bios); |
| 679 | } |
| 680 | |
| 681 | static void process_queued_bios(struct work_struct *work) |
| 682 | { |
| 683 | int r; |
| 684 | unsigned long flags; |
| 685 | struct bio *bio; |
| 686 | struct bio_list bios; |
| 687 | struct blk_plug plug; |
| 688 | struct multipath *m = |
| 689 | container_of(work, struct multipath, process_queued_bios); |
| 690 | |
| 691 | bio_list_init(&bios); |
| 692 | |
| 693 | spin_lock_irqsave(&m->lock, flags); |
| 694 | |
| 695 | if (bio_list_empty(&m->queued_bios)) { |
| 696 | spin_unlock_irqrestore(&m->lock, flags); |
| 697 | return; |
| 698 | } |
| 699 | |
| 700 | bio_list_merge(&bios, &m->queued_bios); |
| 701 | bio_list_init(&m->queued_bios); |
| 702 | |
| 703 | spin_unlock_irqrestore(&m->lock, flags); |
| 704 | |
| 705 | blk_start_plug(&plug); |
| 706 | while ((bio = bio_list_pop(&bios))) { |
| 707 | struct dm_mpath_io *mpio = get_mpio_from_bio(bio); |
| 708 | dm_bio_restore(get_bio_details_from_mpio(mpio), bio); |
| 709 | r = __multipath_map_bio(m, bio, mpio); |
| 710 | switch (r) { |
| 711 | case DM_MAPIO_KILL: |
| 712 | bio->bi_status = BLK_STS_IOERR; |
| 713 | bio_endio(bio); |
| 714 | break; |
| 715 | case DM_MAPIO_REQUEUE: |
| 716 | bio->bi_status = BLK_STS_DM_REQUEUE; |
| 717 | bio_endio(bio); |
| 718 | break; |
| 719 | case DM_MAPIO_REMAPPED: |
| 720 | submit_bio_noacct(bio); |
| 721 | break; |
| 722 | case DM_MAPIO_SUBMITTED: |
| 723 | break; |
| 724 | default: |
| 725 | WARN_ONCE(true, "__multipath_map_bio() returned %d\n", r); |
| 726 | } |
| 727 | } |
| 728 | blk_finish_plug(&plug); |
| 729 | } |
| 730 | |
| 731 | /* |
| 732 | * If we run out of usable paths, should we queue I/O or error it? |
| 733 | */ |
| 734 | static int queue_if_no_path(struct multipath *m, bool queue_if_no_path, |
| 735 | bool save_old_value, const char *caller) |
| 736 | { |
| 737 | unsigned long flags; |
| 738 | bool queue_if_no_path_bit, saved_queue_if_no_path_bit; |
| 739 | const char *dm_dev_name = dm_device_name(dm_table_get_md(m->ti->table)); |
| 740 | |
| 741 | DMDEBUG("%s: %s caller=%s queue_if_no_path=%d save_old_value=%d", |
| 742 | dm_dev_name, __func__, caller, queue_if_no_path, save_old_value); |
| 743 | |
| 744 | spin_lock_irqsave(&m->lock, flags); |
| 745 | |
| 746 | queue_if_no_path_bit = test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags); |
| 747 | saved_queue_if_no_path_bit = test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags); |
| 748 | |
| 749 | if (save_old_value) { |
| 750 | if (unlikely(!queue_if_no_path_bit && saved_queue_if_no_path_bit)) { |
| 751 | DMERR("%s: QIFNP disabled but saved as enabled, saving again loses state, not saving!", |
| 752 | dm_dev_name); |
| 753 | } else |
| 754 | assign_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags, queue_if_no_path_bit); |
| 755 | } else if (!queue_if_no_path && saved_queue_if_no_path_bit) { |
| 756 | /* due to "fail_if_no_path" message, need to honor it. */ |
| 757 | clear_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags); |
| 758 | } |
| 759 | assign_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags, queue_if_no_path); |
| 760 | |
| 761 | DMDEBUG("%s: after %s changes; QIFNP = %d; SQIFNP = %d; DNFS = %d", |
| 762 | dm_dev_name, __func__, |
| 763 | test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags), |
| 764 | test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags), |
| 765 | dm_noflush_suspending(m->ti)); |
| 766 | |
| 767 | spin_unlock_irqrestore(&m->lock, flags); |
| 768 | |
| 769 | if (!queue_if_no_path) { |
| 770 | dm_table_run_md_queue_async(m->ti->table); |
| 771 | process_queued_io_list(m); |
| 772 | } |
| 773 | |
| 774 | return 0; |
| 775 | } |
| 776 | |
| 777 | /* |
| 778 | * If the queue_if_no_path timeout fires, turn off queue_if_no_path and |
| 779 | * process any queued I/O. |
| 780 | */ |
| 781 | static void queue_if_no_path_timeout_work(struct timer_list *t) |
| 782 | { |
| 783 | struct multipath *m = from_timer(m, t, nopath_timer); |
| 784 | struct mapped_device *md = dm_table_get_md(m->ti->table); |
| 785 | |
| 786 | DMWARN("queue_if_no_path timeout on %s, failing queued IO", dm_device_name(md)); |
| 787 | queue_if_no_path(m, false, false, __func__); |
| 788 | } |
| 789 | |
| 790 | /* |
| 791 | * Enable the queue_if_no_path timeout if necessary. |
| 792 | * Called with m->lock held. |
| 793 | */ |
| 794 | static void enable_nopath_timeout(struct multipath *m) |
| 795 | { |
| 796 | unsigned long queue_if_no_path_timeout = |
| 797 | READ_ONCE(queue_if_no_path_timeout_secs) * HZ; |
| 798 | |
| 799 | lockdep_assert_held(&m->lock); |
| 800 | |
| 801 | if (queue_if_no_path_timeout > 0 && |
| 802 | atomic_read(&m->nr_valid_paths) == 0 && |
| 803 | test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) { |
| 804 | mod_timer(&m->nopath_timer, |
| 805 | jiffies + queue_if_no_path_timeout); |
| 806 | } |
| 807 | } |
| 808 | |
| 809 | static void disable_nopath_timeout(struct multipath *m) |
| 810 | { |
| 811 | del_timer_sync(&m->nopath_timer); |
| 812 | } |
| 813 | |
| 814 | /* |
| 815 | * An event is triggered whenever a path is taken out of use. |
| 816 | * Includes path failure and PG bypass. |
| 817 | */ |
| 818 | static void trigger_event(struct work_struct *work) |
| 819 | { |
| 820 | struct multipath *m = |
| 821 | container_of(work, struct multipath, trigger_event); |
| 822 | |
| 823 | dm_table_event(m->ti->table); |
| 824 | } |
| 825 | |
| 826 | /*----------------------------------------------------------------- |
| 827 | * Constructor/argument parsing: |
| 828 | * <#multipath feature args> [<arg>]* |
| 829 | * <#hw_handler args> [hw_handler [<arg>]*] |
| 830 | * <#priority groups> |
| 831 | * <initial priority group> |
| 832 | * [<selector> <#selector args> [<arg>]* |
| 833 | * <#paths> <#per-path selector args> |
| 834 | * [<path> [<arg>]* ]+ ]+ |
| 835 | *---------------------------------------------------------------*/ |
| 836 | static int parse_path_selector(struct dm_arg_set *as, struct priority_group *pg, |
| 837 | struct dm_target *ti) |
| 838 | { |
| 839 | int r; |
| 840 | struct path_selector_type *pst; |
| 841 | unsigned ps_argc; |
| 842 | |
| 843 | static const struct dm_arg _args[] = { |
| 844 | {0, 1024, "invalid number of path selector args"}, |
| 845 | }; |
| 846 | |
| 847 | pst = dm_get_path_selector(dm_shift_arg(as)); |
| 848 | if (!pst) { |
| 849 | ti->error = "unknown path selector type"; |
| 850 | return -EINVAL; |
| 851 | } |
| 852 | |
| 853 | r = dm_read_arg_group(_args, as, &ps_argc, &ti->error); |
| 854 | if (r) { |
| 855 | dm_put_path_selector(pst); |
| 856 | return -EINVAL; |
| 857 | } |
| 858 | |
| 859 | r = pst->create(&pg->ps, ps_argc, as->argv); |
| 860 | if (r) { |
| 861 | dm_put_path_selector(pst); |
| 862 | ti->error = "path selector constructor failed"; |
| 863 | return r; |
| 864 | } |
| 865 | |
| 866 | pg->ps.type = pst; |
| 867 | dm_consume_args(as, ps_argc); |
| 868 | |
| 869 | return 0; |
| 870 | } |
| 871 | |
| 872 | static int setup_scsi_dh(struct block_device *bdev, struct multipath *m, |
| 873 | const char **attached_handler_name, char **error) |
| 874 | { |
| 875 | struct request_queue *q = bdev_get_queue(bdev); |
| 876 | int r; |
| 877 | |
| 878 | if (mpath_double_check_test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, m)) { |
| 879 | retain: |
| 880 | if (*attached_handler_name) { |
| 881 | /* |
| 882 | * Clear any hw_handler_params associated with a |
| 883 | * handler that isn't already attached. |
| 884 | */ |
| 885 | if (m->hw_handler_name && strcmp(*attached_handler_name, m->hw_handler_name)) { |
| 886 | kfree(m->hw_handler_params); |
| 887 | m->hw_handler_params = NULL; |
| 888 | } |
| 889 | |
| 890 | /* |
| 891 | * Reset hw_handler_name to match the attached handler |
| 892 | * |
| 893 | * NB. This modifies the table line to show the actual |
| 894 | * handler instead of the original table passed in. |
| 895 | */ |
| 896 | kfree(m->hw_handler_name); |
| 897 | m->hw_handler_name = *attached_handler_name; |
| 898 | *attached_handler_name = NULL; |
| 899 | } |
| 900 | } |
| 901 | |
| 902 | if (m->hw_handler_name) { |
| 903 | r = scsi_dh_attach(q, m->hw_handler_name); |
| 904 | if (r == -EBUSY) { |
| 905 | char b[BDEVNAME_SIZE]; |
| 906 | |
| 907 | printk(KERN_INFO "dm-mpath: retaining handler on device %s\n", |
| 908 | bdevname(bdev, b)); |
| 909 | goto retain; |
| 910 | } |
| 911 | if (r < 0) { |
| 912 | *error = "error attaching hardware handler"; |
| 913 | return r; |
| 914 | } |
| 915 | |
| 916 | if (m->hw_handler_params) { |
| 917 | r = scsi_dh_set_params(q, m->hw_handler_params); |
| 918 | if (r < 0) { |
| 919 | *error = "unable to set hardware handler parameters"; |
| 920 | return r; |
| 921 | } |
| 922 | } |
| 923 | } |
| 924 | |
| 925 | return 0; |
| 926 | } |
| 927 | |
| 928 | static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps, |
| 929 | struct dm_target *ti) |
| 930 | { |
| 931 | int r; |
| 932 | struct pgpath *p; |
| 933 | struct multipath *m = ti->private; |
| 934 | struct request_queue *q; |
| 935 | const char *attached_handler_name = NULL; |
| 936 | |
| 937 | /* we need at least a path arg */ |
| 938 | if (as->argc < 1) { |
| 939 | ti->error = "no device given"; |
| 940 | return ERR_PTR(-EINVAL); |
| 941 | } |
| 942 | |
| 943 | p = alloc_pgpath(); |
| 944 | if (!p) |
| 945 | return ERR_PTR(-ENOMEM); |
| 946 | |
| 947 | r = dm_get_device(ti, dm_shift_arg(as), dm_table_get_mode(ti->table), |
| 948 | &p->path.dev); |
| 949 | if (r) { |
| 950 | ti->error = "error getting device"; |
| 951 | goto bad; |
| 952 | } |
| 953 | |
| 954 | q = bdev_get_queue(p->path.dev->bdev); |
| 955 | attached_handler_name = scsi_dh_attached_handler_name(q, GFP_KERNEL); |
| 956 | if (attached_handler_name || m->hw_handler_name) { |
| 957 | INIT_DELAYED_WORK(&p->activate_path, activate_path_work); |
| 958 | r = setup_scsi_dh(p->path.dev->bdev, m, &attached_handler_name, &ti->error); |
| 959 | kfree(attached_handler_name); |
| 960 | if (r) { |
| 961 | dm_put_device(ti, p->path.dev); |
| 962 | goto bad; |
| 963 | } |
| 964 | } |
| 965 | |
| 966 | r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error); |
| 967 | if (r) { |
| 968 | dm_put_device(ti, p->path.dev); |
| 969 | goto bad; |
| 970 | } |
| 971 | |
| 972 | return p; |
| 973 | bad: |
| 974 | free_pgpath(p); |
| 975 | return ERR_PTR(r); |
| 976 | } |
| 977 | |
| 978 | static struct priority_group *parse_priority_group(struct dm_arg_set *as, |
| 979 | struct multipath *m) |
| 980 | { |
| 981 | static const struct dm_arg _args[] = { |
| 982 | {1, 1024, "invalid number of paths"}, |
| 983 | {0, 1024, "invalid number of selector args"} |
| 984 | }; |
| 985 | |
| 986 | int r; |
| 987 | unsigned i, nr_selector_args, nr_args; |
| 988 | struct priority_group *pg; |
| 989 | struct dm_target *ti = m->ti; |
| 990 | |
| 991 | if (as->argc < 2) { |
| 992 | as->argc = 0; |
| 993 | ti->error = "not enough priority group arguments"; |
| 994 | return ERR_PTR(-EINVAL); |
| 995 | } |
| 996 | |
| 997 | pg = alloc_priority_group(); |
| 998 | if (!pg) { |
| 999 | ti->error = "couldn't allocate priority group"; |
| 1000 | return ERR_PTR(-ENOMEM); |
| 1001 | } |
| 1002 | pg->m = m; |
| 1003 | |
| 1004 | r = parse_path_selector(as, pg, ti); |
| 1005 | if (r) |
| 1006 | goto bad; |
| 1007 | |
| 1008 | /* |
| 1009 | * read the paths |
| 1010 | */ |
| 1011 | r = dm_read_arg(_args, as, &pg->nr_pgpaths, &ti->error); |
| 1012 | if (r) |
| 1013 | goto bad; |
| 1014 | |
| 1015 | r = dm_read_arg(_args + 1, as, &nr_selector_args, &ti->error); |
| 1016 | if (r) |
| 1017 | goto bad; |
| 1018 | |
| 1019 | nr_args = 1 + nr_selector_args; |
| 1020 | for (i = 0; i < pg->nr_pgpaths; i++) { |
| 1021 | struct pgpath *pgpath; |
| 1022 | struct dm_arg_set path_args; |
| 1023 | |
| 1024 | if (as->argc < nr_args) { |
| 1025 | ti->error = "not enough path parameters"; |
| 1026 | r = -EINVAL; |
| 1027 | goto bad; |
| 1028 | } |
| 1029 | |
| 1030 | path_args.argc = nr_args; |
| 1031 | path_args.argv = as->argv; |
| 1032 | |
| 1033 | pgpath = parse_path(&path_args, &pg->ps, ti); |
| 1034 | if (IS_ERR(pgpath)) { |
| 1035 | r = PTR_ERR(pgpath); |
| 1036 | goto bad; |
| 1037 | } |
| 1038 | |
| 1039 | pgpath->pg = pg; |
| 1040 | list_add_tail(&pgpath->list, &pg->pgpaths); |
| 1041 | dm_consume_args(as, nr_args); |
| 1042 | } |
| 1043 | |
| 1044 | return pg; |
| 1045 | |
| 1046 | bad: |
| 1047 | free_priority_group(pg, ti); |
| 1048 | return ERR_PTR(r); |
| 1049 | } |
| 1050 | |
| 1051 | static int parse_hw_handler(struct dm_arg_set *as, struct multipath *m) |
| 1052 | { |
| 1053 | unsigned hw_argc; |
| 1054 | int ret; |
| 1055 | struct dm_target *ti = m->ti; |
| 1056 | |
| 1057 | static const struct dm_arg _args[] = { |
| 1058 | {0, 1024, "invalid number of hardware handler args"}, |
| 1059 | }; |
| 1060 | |
| 1061 | if (dm_read_arg_group(_args, as, &hw_argc, &ti->error)) |
| 1062 | return -EINVAL; |
| 1063 | |
| 1064 | if (!hw_argc) |
| 1065 | return 0; |
| 1066 | |
| 1067 | if (m->queue_mode == DM_TYPE_BIO_BASED) { |
| 1068 | dm_consume_args(as, hw_argc); |
| 1069 | DMERR("bio-based multipath doesn't allow hardware handler args"); |
| 1070 | return 0; |
| 1071 | } |
| 1072 | |
| 1073 | m->hw_handler_name = kstrdup(dm_shift_arg(as), GFP_KERNEL); |
| 1074 | if (!m->hw_handler_name) |
| 1075 | return -EINVAL; |
| 1076 | |
| 1077 | if (hw_argc > 1) { |
| 1078 | char *p; |
| 1079 | int i, j, len = 4; |
| 1080 | |
| 1081 | for (i = 0; i <= hw_argc - 2; i++) |
| 1082 | len += strlen(as->argv[i]) + 1; |
| 1083 | p = m->hw_handler_params = kzalloc(len, GFP_KERNEL); |
| 1084 | if (!p) { |
| 1085 | ti->error = "memory allocation failed"; |
| 1086 | ret = -ENOMEM; |
| 1087 | goto fail; |
| 1088 | } |
| 1089 | j = sprintf(p, "%d", hw_argc - 1); |
| 1090 | for (i = 0, p+=j+1; i <= hw_argc - 2; i++, p+=j+1) |
| 1091 | j = sprintf(p, "%s", as->argv[i]); |
| 1092 | } |
| 1093 | dm_consume_args(as, hw_argc - 1); |
| 1094 | |
| 1095 | return 0; |
| 1096 | fail: |
| 1097 | kfree(m->hw_handler_name); |
| 1098 | m->hw_handler_name = NULL; |
| 1099 | return ret; |
| 1100 | } |
| 1101 | |
| 1102 | static int parse_features(struct dm_arg_set *as, struct multipath *m) |
| 1103 | { |
| 1104 | int r; |
| 1105 | unsigned argc; |
| 1106 | struct dm_target *ti = m->ti; |
| 1107 | const char *arg_name; |
| 1108 | |
| 1109 | static const struct dm_arg _args[] = { |
| 1110 | {0, 8, "invalid number of feature args"}, |
| 1111 | {1, 50, "pg_init_retries must be between 1 and 50"}, |
| 1112 | {0, 60000, "pg_init_delay_msecs must be between 0 and 60000"}, |
| 1113 | }; |
| 1114 | |
| 1115 | r = dm_read_arg_group(_args, as, &argc, &ti->error); |
| 1116 | if (r) |
| 1117 | return -EINVAL; |
| 1118 | |
| 1119 | if (!argc) |
| 1120 | return 0; |
| 1121 | |
| 1122 | do { |
| 1123 | arg_name = dm_shift_arg(as); |
| 1124 | argc--; |
| 1125 | |
| 1126 | if (!strcasecmp(arg_name, "queue_if_no_path")) { |
| 1127 | r = queue_if_no_path(m, true, false, __func__); |
| 1128 | continue; |
| 1129 | } |
| 1130 | |
| 1131 | if (!strcasecmp(arg_name, "retain_attached_hw_handler")) { |
| 1132 | set_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags); |
| 1133 | continue; |
| 1134 | } |
| 1135 | |
| 1136 | if (!strcasecmp(arg_name, "pg_init_retries") && |
| 1137 | (argc >= 1)) { |
| 1138 | r = dm_read_arg(_args + 1, as, &m->pg_init_retries, &ti->error); |
| 1139 | argc--; |
| 1140 | continue; |
| 1141 | } |
| 1142 | |
| 1143 | if (!strcasecmp(arg_name, "pg_init_delay_msecs") && |
| 1144 | (argc >= 1)) { |
| 1145 | r = dm_read_arg(_args + 2, as, &m->pg_init_delay_msecs, &ti->error); |
| 1146 | argc--; |
| 1147 | continue; |
| 1148 | } |
| 1149 | |
| 1150 | if (!strcasecmp(arg_name, "queue_mode") && |
| 1151 | (argc >= 1)) { |
| 1152 | const char *queue_mode_name = dm_shift_arg(as); |
| 1153 | |
| 1154 | if (!strcasecmp(queue_mode_name, "bio")) |
| 1155 | m->queue_mode = DM_TYPE_BIO_BASED; |
| 1156 | else if (!strcasecmp(queue_mode_name, "rq") || |
| 1157 | !strcasecmp(queue_mode_name, "mq")) |
| 1158 | m->queue_mode = DM_TYPE_REQUEST_BASED; |
| 1159 | else { |
| 1160 | ti->error = "Unknown 'queue_mode' requested"; |
| 1161 | r = -EINVAL; |
| 1162 | } |
| 1163 | argc--; |
| 1164 | continue; |
| 1165 | } |
| 1166 | |
| 1167 | ti->error = "Unrecognised multipath feature request"; |
| 1168 | r = -EINVAL; |
| 1169 | } while (argc && !r); |
| 1170 | |
| 1171 | return r; |
| 1172 | } |
| 1173 | |
| 1174 | static int multipath_ctr(struct dm_target *ti, unsigned argc, char **argv) |
| 1175 | { |
| 1176 | /* target arguments */ |
| 1177 | static const struct dm_arg _args[] = { |
| 1178 | {0, 1024, "invalid number of priority groups"}, |
| 1179 | {0, 1024, "invalid initial priority group number"}, |
| 1180 | }; |
| 1181 | |
| 1182 | int r; |
| 1183 | struct multipath *m; |
| 1184 | struct dm_arg_set as; |
| 1185 | unsigned pg_count = 0; |
| 1186 | unsigned next_pg_num; |
| 1187 | unsigned long flags; |
| 1188 | |
| 1189 | as.argc = argc; |
| 1190 | as.argv = argv; |
| 1191 | |
| 1192 | m = alloc_multipath(ti); |
| 1193 | if (!m) { |
| 1194 | ti->error = "can't allocate multipath"; |
| 1195 | return -EINVAL; |
| 1196 | } |
| 1197 | |
| 1198 | r = parse_features(&as, m); |
| 1199 | if (r) |
| 1200 | goto bad; |
| 1201 | |
| 1202 | r = alloc_multipath_stage2(ti, m); |
| 1203 | if (r) |
| 1204 | goto bad; |
| 1205 | |
| 1206 | r = parse_hw_handler(&as, m); |
| 1207 | if (r) |
| 1208 | goto bad; |
| 1209 | |
| 1210 | r = dm_read_arg(_args, &as, &m->nr_priority_groups, &ti->error); |
| 1211 | if (r) |
| 1212 | goto bad; |
| 1213 | |
| 1214 | r = dm_read_arg(_args + 1, &as, &next_pg_num, &ti->error); |
| 1215 | if (r) |
| 1216 | goto bad; |
| 1217 | |
| 1218 | if ((!m->nr_priority_groups && next_pg_num) || |
| 1219 | (m->nr_priority_groups && !next_pg_num)) { |
| 1220 | ti->error = "invalid initial priority group"; |
| 1221 | r = -EINVAL; |
| 1222 | goto bad; |
| 1223 | } |
| 1224 | |
| 1225 | /* parse the priority groups */ |
| 1226 | while (as.argc) { |
| 1227 | struct priority_group *pg; |
| 1228 | unsigned nr_valid_paths = atomic_read(&m->nr_valid_paths); |
| 1229 | |
| 1230 | pg = parse_priority_group(&as, m); |
| 1231 | if (IS_ERR(pg)) { |
| 1232 | r = PTR_ERR(pg); |
| 1233 | goto bad; |
| 1234 | } |
| 1235 | |
| 1236 | nr_valid_paths += pg->nr_pgpaths; |
| 1237 | atomic_set(&m->nr_valid_paths, nr_valid_paths); |
| 1238 | |
| 1239 | list_add_tail(&pg->list, &m->priority_groups); |
| 1240 | pg_count++; |
| 1241 | pg->pg_num = pg_count; |
| 1242 | if (!--next_pg_num) |
| 1243 | m->next_pg = pg; |
| 1244 | } |
| 1245 | |
| 1246 | if (pg_count != m->nr_priority_groups) { |
| 1247 | ti->error = "priority group count mismatch"; |
| 1248 | r = -EINVAL; |
| 1249 | goto bad; |
| 1250 | } |
| 1251 | |
| 1252 | spin_lock_irqsave(&m->lock, flags); |
| 1253 | enable_nopath_timeout(m); |
| 1254 | spin_unlock_irqrestore(&m->lock, flags); |
| 1255 | |
| 1256 | ti->num_flush_bios = 1; |
| 1257 | ti->num_discard_bios = 1; |
| 1258 | ti->num_write_same_bios = 1; |
| 1259 | ti->num_write_zeroes_bios = 1; |
| 1260 | if (m->queue_mode == DM_TYPE_BIO_BASED) |
| 1261 | ti->per_io_data_size = multipath_per_bio_data_size(); |
| 1262 | else |
| 1263 | ti->per_io_data_size = sizeof(struct dm_mpath_io); |
| 1264 | |
| 1265 | return 0; |
| 1266 | |
| 1267 | bad: |
| 1268 | free_multipath(m); |
| 1269 | return r; |
| 1270 | } |
| 1271 | |
| 1272 | static void multipath_wait_for_pg_init_completion(struct multipath *m) |
| 1273 | { |
| 1274 | DEFINE_WAIT(wait); |
| 1275 | |
| 1276 | while (1) { |
| 1277 | prepare_to_wait(&m->pg_init_wait, &wait, TASK_UNINTERRUPTIBLE); |
| 1278 | |
| 1279 | if (!atomic_read(&m->pg_init_in_progress)) |
| 1280 | break; |
| 1281 | |
| 1282 | io_schedule(); |
| 1283 | } |
| 1284 | finish_wait(&m->pg_init_wait, &wait); |
| 1285 | } |
| 1286 | |
| 1287 | static void flush_multipath_work(struct multipath *m) |
| 1288 | { |
| 1289 | if (m->hw_handler_name) { |
| 1290 | set_bit(MPATHF_PG_INIT_DISABLED, &m->flags); |
| 1291 | smp_mb__after_atomic(); |
| 1292 | |
| 1293 | if (atomic_read(&m->pg_init_in_progress)) |
| 1294 | flush_workqueue(kmpath_handlerd); |
| 1295 | multipath_wait_for_pg_init_completion(m); |
| 1296 | |
| 1297 | clear_bit(MPATHF_PG_INIT_DISABLED, &m->flags); |
| 1298 | smp_mb__after_atomic(); |
| 1299 | } |
| 1300 | |
| 1301 | if (m->queue_mode == DM_TYPE_BIO_BASED) |
| 1302 | flush_work(&m->process_queued_bios); |
| 1303 | flush_work(&m->trigger_event); |
| 1304 | } |
| 1305 | |
| 1306 | static void multipath_dtr(struct dm_target *ti) |
| 1307 | { |
| 1308 | struct multipath *m = ti->private; |
| 1309 | |
| 1310 | disable_nopath_timeout(m); |
| 1311 | flush_multipath_work(m); |
| 1312 | free_multipath(m); |
| 1313 | } |
| 1314 | |
| 1315 | /* |
| 1316 | * Take a path out of use. |
| 1317 | */ |
| 1318 | static int fail_path(struct pgpath *pgpath) |
| 1319 | { |
| 1320 | unsigned long flags; |
| 1321 | struct multipath *m = pgpath->pg->m; |
| 1322 | |
| 1323 | spin_lock_irqsave(&m->lock, flags); |
| 1324 | |
| 1325 | if (!pgpath->is_active) |
| 1326 | goto out; |
| 1327 | |
| 1328 | DMWARN("%s: Failing path %s.", |
| 1329 | dm_device_name(dm_table_get_md(m->ti->table)), |
| 1330 | pgpath->path.dev->name); |
| 1331 | |
| 1332 | pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path); |
| 1333 | pgpath->is_active = false; |
| 1334 | pgpath->fail_count++; |
| 1335 | |
| 1336 | atomic_dec(&m->nr_valid_paths); |
| 1337 | |
| 1338 | if (pgpath == m->current_pgpath) |
| 1339 | m->current_pgpath = NULL; |
| 1340 | |
| 1341 | dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti, |
| 1342 | pgpath->path.dev->name, atomic_read(&m->nr_valid_paths)); |
| 1343 | |
| 1344 | schedule_work(&m->trigger_event); |
| 1345 | |
| 1346 | enable_nopath_timeout(m); |
| 1347 | |
| 1348 | out: |
| 1349 | spin_unlock_irqrestore(&m->lock, flags); |
| 1350 | |
| 1351 | return 0; |
| 1352 | } |
| 1353 | |
| 1354 | /* |
| 1355 | * Reinstate a previously-failed path |
| 1356 | */ |
| 1357 | static int reinstate_path(struct pgpath *pgpath) |
| 1358 | { |
| 1359 | int r = 0, run_queue = 0; |
| 1360 | unsigned long flags; |
| 1361 | struct multipath *m = pgpath->pg->m; |
| 1362 | unsigned nr_valid_paths; |
| 1363 | |
| 1364 | spin_lock_irqsave(&m->lock, flags); |
| 1365 | |
| 1366 | if (pgpath->is_active) |
| 1367 | goto out; |
| 1368 | |
| 1369 | DMWARN("%s: Reinstating path %s.", |
| 1370 | dm_device_name(dm_table_get_md(m->ti->table)), |
| 1371 | pgpath->path.dev->name); |
| 1372 | |
| 1373 | r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path); |
| 1374 | if (r) |
| 1375 | goto out; |
| 1376 | |
| 1377 | pgpath->is_active = true; |
| 1378 | |
| 1379 | nr_valid_paths = atomic_inc_return(&m->nr_valid_paths); |
| 1380 | if (nr_valid_paths == 1) { |
| 1381 | m->current_pgpath = NULL; |
| 1382 | run_queue = 1; |
| 1383 | } else if (m->hw_handler_name && (m->current_pg == pgpath->pg)) { |
| 1384 | if (queue_work(kmpath_handlerd, &pgpath->activate_path.work)) |
| 1385 | atomic_inc(&m->pg_init_in_progress); |
| 1386 | } |
| 1387 | |
| 1388 | dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti, |
| 1389 | pgpath->path.dev->name, nr_valid_paths); |
| 1390 | |
| 1391 | schedule_work(&m->trigger_event); |
| 1392 | |
| 1393 | out: |
| 1394 | spin_unlock_irqrestore(&m->lock, flags); |
| 1395 | if (run_queue) { |
| 1396 | dm_table_run_md_queue_async(m->ti->table); |
| 1397 | process_queued_io_list(m); |
| 1398 | } |
| 1399 | |
| 1400 | if (pgpath->is_active) |
| 1401 | disable_nopath_timeout(m); |
| 1402 | |
| 1403 | return r; |
| 1404 | } |
| 1405 | |
| 1406 | /* |
| 1407 | * Fail or reinstate all paths that match the provided struct dm_dev. |
| 1408 | */ |
| 1409 | static int action_dev(struct multipath *m, struct dm_dev *dev, |
| 1410 | action_fn action) |
| 1411 | { |
| 1412 | int r = -EINVAL; |
| 1413 | struct pgpath *pgpath; |
| 1414 | struct priority_group *pg; |
| 1415 | |
| 1416 | list_for_each_entry(pg, &m->priority_groups, list) { |
| 1417 | list_for_each_entry(pgpath, &pg->pgpaths, list) { |
| 1418 | if (pgpath->path.dev == dev) |
| 1419 | r = action(pgpath); |
| 1420 | } |
| 1421 | } |
| 1422 | |
| 1423 | return r; |
| 1424 | } |
| 1425 | |
| 1426 | /* |
| 1427 | * Temporarily try to avoid having to use the specified PG |
| 1428 | */ |
| 1429 | static void bypass_pg(struct multipath *m, struct priority_group *pg, |
| 1430 | bool bypassed) |
| 1431 | { |
| 1432 | unsigned long flags; |
| 1433 | |
| 1434 | spin_lock_irqsave(&m->lock, flags); |
| 1435 | |
| 1436 | pg->bypassed = bypassed; |
| 1437 | m->current_pgpath = NULL; |
| 1438 | m->current_pg = NULL; |
| 1439 | |
| 1440 | spin_unlock_irqrestore(&m->lock, flags); |
| 1441 | |
| 1442 | schedule_work(&m->trigger_event); |
| 1443 | } |
| 1444 | |
| 1445 | /* |
| 1446 | * Switch to using the specified PG from the next I/O that gets mapped |
| 1447 | */ |
| 1448 | static int switch_pg_num(struct multipath *m, const char *pgstr) |
| 1449 | { |
| 1450 | struct priority_group *pg; |
| 1451 | unsigned pgnum; |
| 1452 | unsigned long flags; |
| 1453 | char dummy; |
| 1454 | |
| 1455 | if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum || |
| 1456 | !m->nr_priority_groups || (pgnum > m->nr_priority_groups)) { |
| 1457 | DMWARN("invalid PG number supplied to switch_pg_num"); |
| 1458 | return -EINVAL; |
| 1459 | } |
| 1460 | |
| 1461 | spin_lock_irqsave(&m->lock, flags); |
| 1462 | list_for_each_entry(pg, &m->priority_groups, list) { |
| 1463 | pg->bypassed = false; |
| 1464 | if (--pgnum) |
| 1465 | continue; |
| 1466 | |
| 1467 | m->current_pgpath = NULL; |
| 1468 | m->current_pg = NULL; |
| 1469 | m->next_pg = pg; |
| 1470 | } |
| 1471 | spin_unlock_irqrestore(&m->lock, flags); |
| 1472 | |
| 1473 | schedule_work(&m->trigger_event); |
| 1474 | return 0; |
| 1475 | } |
| 1476 | |
| 1477 | /* |
| 1478 | * Set/clear bypassed status of a PG. |
| 1479 | * PGs are numbered upwards from 1 in the order they were declared. |
| 1480 | */ |
| 1481 | static int bypass_pg_num(struct multipath *m, const char *pgstr, bool bypassed) |
| 1482 | { |
| 1483 | struct priority_group *pg; |
| 1484 | unsigned pgnum; |
| 1485 | char dummy; |
| 1486 | |
| 1487 | if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum || |
| 1488 | !m->nr_priority_groups || (pgnum > m->nr_priority_groups)) { |
| 1489 | DMWARN("invalid PG number supplied to bypass_pg"); |
| 1490 | return -EINVAL; |
| 1491 | } |
| 1492 | |
| 1493 | list_for_each_entry(pg, &m->priority_groups, list) { |
| 1494 | if (!--pgnum) |
| 1495 | break; |
| 1496 | } |
| 1497 | |
| 1498 | bypass_pg(m, pg, bypassed); |
| 1499 | return 0; |
| 1500 | } |
| 1501 | |
| 1502 | /* |
| 1503 | * Should we retry pg_init immediately? |
| 1504 | */ |
| 1505 | static bool pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath) |
| 1506 | { |
| 1507 | unsigned long flags; |
| 1508 | bool limit_reached = false; |
| 1509 | |
| 1510 | spin_lock_irqsave(&m->lock, flags); |
| 1511 | |
| 1512 | if (atomic_read(&m->pg_init_count) <= m->pg_init_retries && |
| 1513 | !test_bit(MPATHF_PG_INIT_DISABLED, &m->flags)) |
| 1514 | set_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); |
| 1515 | else |
| 1516 | limit_reached = true; |
| 1517 | |
| 1518 | spin_unlock_irqrestore(&m->lock, flags); |
| 1519 | |
| 1520 | return limit_reached; |
| 1521 | } |
| 1522 | |
| 1523 | static void pg_init_done(void *data, int errors) |
| 1524 | { |
| 1525 | struct pgpath *pgpath = data; |
| 1526 | struct priority_group *pg = pgpath->pg; |
| 1527 | struct multipath *m = pg->m; |
| 1528 | unsigned long flags; |
| 1529 | bool delay_retry = false; |
| 1530 | |
| 1531 | /* device or driver problems */ |
| 1532 | switch (errors) { |
| 1533 | case SCSI_DH_OK: |
| 1534 | break; |
| 1535 | case SCSI_DH_NOSYS: |
| 1536 | if (!m->hw_handler_name) { |
| 1537 | errors = 0; |
| 1538 | break; |
| 1539 | } |
| 1540 | DMERR("Could not failover the device: Handler scsi_dh_%s " |
| 1541 | "Error %d.", m->hw_handler_name, errors); |
| 1542 | /* |
| 1543 | * Fail path for now, so we do not ping pong |
| 1544 | */ |
| 1545 | fail_path(pgpath); |
| 1546 | break; |
| 1547 | case SCSI_DH_DEV_TEMP_BUSY: |
| 1548 | /* |
| 1549 | * Probably doing something like FW upgrade on the |
| 1550 | * controller so try the other pg. |
| 1551 | */ |
| 1552 | bypass_pg(m, pg, true); |
| 1553 | break; |
| 1554 | case SCSI_DH_RETRY: |
| 1555 | /* Wait before retrying. */ |
| 1556 | delay_retry = true; |
| 1557 | fallthrough; |
| 1558 | case SCSI_DH_IMM_RETRY: |
| 1559 | case SCSI_DH_RES_TEMP_UNAVAIL: |
| 1560 | if (pg_init_limit_reached(m, pgpath)) |
| 1561 | fail_path(pgpath); |
| 1562 | errors = 0; |
| 1563 | break; |
| 1564 | case SCSI_DH_DEV_OFFLINED: |
| 1565 | default: |
| 1566 | /* |
| 1567 | * We probably do not want to fail the path for a device |
| 1568 | * error, but this is what the old dm did. In future |
| 1569 | * patches we can do more advanced handling. |
| 1570 | */ |
| 1571 | fail_path(pgpath); |
| 1572 | } |
| 1573 | |
| 1574 | spin_lock_irqsave(&m->lock, flags); |
| 1575 | if (errors) { |
| 1576 | if (pgpath == m->current_pgpath) { |
| 1577 | DMERR("Could not failover device. Error %d.", errors); |
| 1578 | m->current_pgpath = NULL; |
| 1579 | m->current_pg = NULL; |
| 1580 | } |
| 1581 | } else if (!test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) |
| 1582 | pg->bypassed = false; |
| 1583 | |
| 1584 | if (atomic_dec_return(&m->pg_init_in_progress) > 0) |
| 1585 | /* Activations of other paths are still on going */ |
| 1586 | goto out; |
| 1587 | |
| 1588 | if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) { |
| 1589 | if (delay_retry) |
| 1590 | set_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags); |
| 1591 | else |
| 1592 | clear_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags); |
| 1593 | |
| 1594 | if (__pg_init_all_paths(m)) |
| 1595 | goto out; |
| 1596 | } |
| 1597 | clear_bit(MPATHF_QUEUE_IO, &m->flags); |
| 1598 | |
| 1599 | process_queued_io_list(m); |
| 1600 | |
| 1601 | /* |
| 1602 | * Wake up any thread waiting to suspend. |
| 1603 | */ |
| 1604 | wake_up(&m->pg_init_wait); |
| 1605 | |
| 1606 | out: |
| 1607 | spin_unlock_irqrestore(&m->lock, flags); |
| 1608 | } |
| 1609 | |
| 1610 | static void activate_or_offline_path(struct pgpath *pgpath) |
| 1611 | { |
| 1612 | struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev); |
| 1613 | |
| 1614 | if (pgpath->is_active && !blk_queue_dying(q)) |
| 1615 | scsi_dh_activate(q, pg_init_done, pgpath); |
| 1616 | else |
| 1617 | pg_init_done(pgpath, SCSI_DH_DEV_OFFLINED); |
| 1618 | } |
| 1619 | |
| 1620 | static void activate_path_work(struct work_struct *work) |
| 1621 | { |
| 1622 | struct pgpath *pgpath = |
| 1623 | container_of(work, struct pgpath, activate_path.work); |
| 1624 | |
| 1625 | activate_or_offline_path(pgpath); |
| 1626 | } |
| 1627 | |
| 1628 | static int multipath_end_io(struct dm_target *ti, struct request *clone, |
| 1629 | blk_status_t error, union map_info *map_context) |
| 1630 | { |
| 1631 | struct dm_mpath_io *mpio = get_mpio(map_context); |
| 1632 | struct pgpath *pgpath = mpio->pgpath; |
| 1633 | int r = DM_ENDIO_DONE; |
| 1634 | |
| 1635 | /* |
| 1636 | * We don't queue any clone request inside the multipath target |
| 1637 | * during end I/O handling, since those clone requests don't have |
| 1638 | * bio clones. If we queue them inside the multipath target, |
| 1639 | * we need to make bio clones, that requires memory allocation. |
| 1640 | * (See drivers/md/dm-rq.c:end_clone_bio() about why the clone requests |
| 1641 | * don't have bio clones.) |
| 1642 | * Instead of queueing the clone request here, we queue the original |
| 1643 | * request into dm core, which will remake a clone request and |
| 1644 | * clone bios for it and resubmit it later. |
| 1645 | */ |
| 1646 | if (error && blk_path_error(error)) { |
| 1647 | struct multipath *m = ti->private; |
| 1648 | |
| 1649 | if (error == BLK_STS_RESOURCE) |
| 1650 | r = DM_ENDIO_DELAY_REQUEUE; |
| 1651 | else |
| 1652 | r = DM_ENDIO_REQUEUE; |
| 1653 | |
| 1654 | if (pgpath) |
| 1655 | fail_path(pgpath); |
| 1656 | |
| 1657 | if (!atomic_read(&m->nr_valid_paths) && |
| 1658 | !must_push_back_rq(m)) { |
| 1659 | if (error == BLK_STS_IOERR) |
| 1660 | dm_report_EIO(m); |
| 1661 | /* complete with the original error */ |
| 1662 | r = DM_ENDIO_DONE; |
| 1663 | } |
| 1664 | } |
| 1665 | |
| 1666 | if (pgpath) { |
| 1667 | struct path_selector *ps = &pgpath->pg->ps; |
| 1668 | |
| 1669 | if (ps->type->end_io) |
| 1670 | ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes, |
| 1671 | clone->io_start_time_ns); |
| 1672 | } |
| 1673 | |
| 1674 | return r; |
| 1675 | } |
| 1676 | |
| 1677 | static int multipath_end_io_bio(struct dm_target *ti, struct bio *clone, |
| 1678 | blk_status_t *error) |
| 1679 | { |
| 1680 | struct multipath *m = ti->private; |
| 1681 | struct dm_mpath_io *mpio = get_mpio_from_bio(clone); |
| 1682 | struct pgpath *pgpath = mpio->pgpath; |
| 1683 | unsigned long flags; |
| 1684 | int r = DM_ENDIO_DONE; |
| 1685 | |
| 1686 | if (!*error || !blk_path_error(*error)) |
| 1687 | goto done; |
| 1688 | |
| 1689 | if (pgpath) |
| 1690 | fail_path(pgpath); |
| 1691 | |
| 1692 | if (!atomic_read(&m->nr_valid_paths)) { |
| 1693 | spin_lock_irqsave(&m->lock, flags); |
| 1694 | if (!test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) { |
| 1695 | if (__must_push_back(m)) { |
| 1696 | r = DM_ENDIO_REQUEUE; |
| 1697 | } else { |
| 1698 | dm_report_EIO(m); |
| 1699 | *error = BLK_STS_IOERR; |
| 1700 | } |
| 1701 | spin_unlock_irqrestore(&m->lock, flags); |
| 1702 | goto done; |
| 1703 | } |
| 1704 | spin_unlock_irqrestore(&m->lock, flags); |
| 1705 | } |
| 1706 | |
| 1707 | multipath_queue_bio(m, clone); |
| 1708 | r = DM_ENDIO_INCOMPLETE; |
| 1709 | done: |
| 1710 | if (pgpath) { |
| 1711 | struct path_selector *ps = &pgpath->pg->ps; |
| 1712 | |
| 1713 | if (ps->type->end_io) |
| 1714 | ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes, |
| 1715 | dm_start_time_ns_from_clone(clone)); |
| 1716 | } |
| 1717 | |
| 1718 | return r; |
| 1719 | } |
| 1720 | |
| 1721 | /* |
| 1722 | * Suspend with flush can't complete until all the I/O is processed |
| 1723 | * so if the last path fails we must error any remaining I/O. |
| 1724 | * - Note that if the freeze_bdev fails while suspending, the |
| 1725 | * queue_if_no_path state is lost - userspace should reset it. |
| 1726 | * Otherwise, during noflush suspend, queue_if_no_path will not change. |
| 1727 | */ |
| 1728 | static void multipath_presuspend(struct dm_target *ti) |
| 1729 | { |
| 1730 | struct multipath *m = ti->private; |
| 1731 | |
| 1732 | /* FIXME: bio-based shouldn't need to always disable queue_if_no_path */ |
| 1733 | if (m->queue_mode == DM_TYPE_BIO_BASED || !dm_noflush_suspending(m->ti)) |
| 1734 | queue_if_no_path(m, false, true, __func__); |
| 1735 | } |
| 1736 | |
| 1737 | static void multipath_postsuspend(struct dm_target *ti) |
| 1738 | { |
| 1739 | struct multipath *m = ti->private; |
| 1740 | |
| 1741 | mutex_lock(&m->work_mutex); |
| 1742 | flush_multipath_work(m); |
| 1743 | mutex_unlock(&m->work_mutex); |
| 1744 | } |
| 1745 | |
| 1746 | /* |
| 1747 | * Restore the queue_if_no_path setting. |
| 1748 | */ |
| 1749 | static void multipath_resume(struct dm_target *ti) |
| 1750 | { |
| 1751 | struct multipath *m = ti->private; |
| 1752 | unsigned long flags; |
| 1753 | |
| 1754 | spin_lock_irqsave(&m->lock, flags); |
| 1755 | if (test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags)) { |
| 1756 | set_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags); |
| 1757 | clear_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags); |
| 1758 | } |
| 1759 | |
| 1760 | DMDEBUG("%s: %s finished; QIFNP = %d; SQIFNP = %d", |
| 1761 | dm_device_name(dm_table_get_md(m->ti->table)), __func__, |
| 1762 | test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags), |
| 1763 | test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags)); |
| 1764 | |
| 1765 | spin_unlock_irqrestore(&m->lock, flags); |
| 1766 | } |
| 1767 | |
| 1768 | /* |
| 1769 | * Info output has the following format: |
| 1770 | * num_multipath_feature_args [multipath_feature_args]* |
| 1771 | * num_handler_status_args [handler_status_args]* |
| 1772 | * num_groups init_group_number |
| 1773 | * [A|D|E num_ps_status_args [ps_status_args]* |
| 1774 | * num_paths num_selector_args |
| 1775 | * [path_dev A|F fail_count [selector_args]* ]+ ]+ |
| 1776 | * |
| 1777 | * Table output has the following format (identical to the constructor string): |
| 1778 | * num_feature_args [features_args]* |
| 1779 | * num_handler_args hw_handler [hw_handler_args]* |
| 1780 | * num_groups init_group_number |
| 1781 | * [priority selector-name num_ps_args [ps_args]* |
| 1782 | * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+ |
| 1783 | */ |
| 1784 | static void multipath_status(struct dm_target *ti, status_type_t type, |
| 1785 | unsigned status_flags, char *result, unsigned maxlen) |
| 1786 | { |
| 1787 | int sz = 0; |
| 1788 | unsigned long flags; |
| 1789 | struct multipath *m = ti->private; |
| 1790 | struct priority_group *pg; |
| 1791 | struct pgpath *p; |
| 1792 | unsigned pg_num; |
| 1793 | char state; |
| 1794 | |
| 1795 | spin_lock_irqsave(&m->lock, flags); |
| 1796 | |
| 1797 | /* Features */ |
| 1798 | if (type == STATUSTYPE_INFO) |
| 1799 | DMEMIT("2 %u %u ", test_bit(MPATHF_QUEUE_IO, &m->flags), |
| 1800 | atomic_read(&m->pg_init_count)); |
| 1801 | else { |
| 1802 | DMEMIT("%u ", test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) + |
| 1803 | (m->pg_init_retries > 0) * 2 + |
| 1804 | (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2 + |
| 1805 | test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags) + |
| 1806 | (m->queue_mode != DM_TYPE_REQUEST_BASED) * 2); |
| 1807 | |
| 1808 | if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) |
| 1809 | DMEMIT("queue_if_no_path "); |
| 1810 | if (m->pg_init_retries) |
| 1811 | DMEMIT("pg_init_retries %u ", m->pg_init_retries); |
| 1812 | if (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) |
| 1813 | DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs); |
| 1814 | if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags)) |
| 1815 | DMEMIT("retain_attached_hw_handler "); |
| 1816 | if (m->queue_mode != DM_TYPE_REQUEST_BASED) { |
| 1817 | switch(m->queue_mode) { |
| 1818 | case DM_TYPE_BIO_BASED: |
| 1819 | DMEMIT("queue_mode bio "); |
| 1820 | break; |
| 1821 | default: |
| 1822 | WARN_ON_ONCE(true); |
| 1823 | break; |
| 1824 | } |
| 1825 | } |
| 1826 | } |
| 1827 | |
| 1828 | if (!m->hw_handler_name || type == STATUSTYPE_INFO) |
| 1829 | DMEMIT("0 "); |
| 1830 | else |
| 1831 | DMEMIT("1 %s ", m->hw_handler_name); |
| 1832 | |
| 1833 | DMEMIT("%u ", m->nr_priority_groups); |
| 1834 | |
| 1835 | if (m->next_pg) |
| 1836 | pg_num = m->next_pg->pg_num; |
| 1837 | else if (m->current_pg) |
| 1838 | pg_num = m->current_pg->pg_num; |
| 1839 | else |
| 1840 | pg_num = (m->nr_priority_groups ? 1 : 0); |
| 1841 | |
| 1842 | DMEMIT("%u ", pg_num); |
| 1843 | |
| 1844 | switch (type) { |
| 1845 | case STATUSTYPE_INFO: |
| 1846 | list_for_each_entry(pg, &m->priority_groups, list) { |
| 1847 | if (pg->bypassed) |
| 1848 | state = 'D'; /* Disabled */ |
| 1849 | else if (pg == m->current_pg) |
| 1850 | state = 'A'; /* Currently Active */ |
| 1851 | else |
| 1852 | state = 'E'; /* Enabled */ |
| 1853 | |
| 1854 | DMEMIT("%c ", state); |
| 1855 | |
| 1856 | if (pg->ps.type->status) |
| 1857 | sz += pg->ps.type->status(&pg->ps, NULL, type, |
| 1858 | result + sz, |
| 1859 | maxlen - sz); |
| 1860 | else |
| 1861 | DMEMIT("0 "); |
| 1862 | |
| 1863 | DMEMIT("%u %u ", pg->nr_pgpaths, |
| 1864 | pg->ps.type->info_args); |
| 1865 | |
| 1866 | list_for_each_entry(p, &pg->pgpaths, list) { |
| 1867 | DMEMIT("%s %s %u ", p->path.dev->name, |
| 1868 | p->is_active ? "A" : "F", |
| 1869 | p->fail_count); |
| 1870 | if (pg->ps.type->status) |
| 1871 | sz += pg->ps.type->status(&pg->ps, |
| 1872 | &p->path, type, result + sz, |
| 1873 | maxlen - sz); |
| 1874 | } |
| 1875 | } |
| 1876 | break; |
| 1877 | |
| 1878 | case STATUSTYPE_TABLE: |
| 1879 | list_for_each_entry(pg, &m->priority_groups, list) { |
| 1880 | DMEMIT("%s ", pg->ps.type->name); |
| 1881 | |
| 1882 | if (pg->ps.type->status) |
| 1883 | sz += pg->ps.type->status(&pg->ps, NULL, type, |
| 1884 | result + sz, |
| 1885 | maxlen - sz); |
| 1886 | else |
| 1887 | DMEMIT("0 "); |
| 1888 | |
| 1889 | DMEMIT("%u %u ", pg->nr_pgpaths, |
| 1890 | pg->ps.type->table_args); |
| 1891 | |
| 1892 | list_for_each_entry(p, &pg->pgpaths, list) { |
| 1893 | DMEMIT("%s ", p->path.dev->name); |
| 1894 | if (pg->ps.type->status) |
| 1895 | sz += pg->ps.type->status(&pg->ps, |
| 1896 | &p->path, type, result + sz, |
| 1897 | maxlen - sz); |
| 1898 | } |
| 1899 | } |
| 1900 | break; |
| 1901 | } |
| 1902 | |
| 1903 | spin_unlock_irqrestore(&m->lock, flags); |
| 1904 | } |
| 1905 | |
| 1906 | static int multipath_message(struct dm_target *ti, unsigned argc, char **argv, |
| 1907 | char *result, unsigned maxlen) |
| 1908 | { |
| 1909 | int r = -EINVAL; |
| 1910 | struct dm_dev *dev; |
| 1911 | struct multipath *m = ti->private; |
| 1912 | action_fn action; |
| 1913 | unsigned long flags; |
| 1914 | |
| 1915 | mutex_lock(&m->work_mutex); |
| 1916 | |
| 1917 | if (dm_suspended(ti)) { |
| 1918 | r = -EBUSY; |
| 1919 | goto out; |
| 1920 | } |
| 1921 | |
| 1922 | if (argc == 1) { |
| 1923 | if (!strcasecmp(argv[0], "queue_if_no_path")) { |
| 1924 | r = queue_if_no_path(m, true, false, __func__); |
| 1925 | spin_lock_irqsave(&m->lock, flags); |
| 1926 | enable_nopath_timeout(m); |
| 1927 | spin_unlock_irqrestore(&m->lock, flags); |
| 1928 | goto out; |
| 1929 | } else if (!strcasecmp(argv[0], "fail_if_no_path")) { |
| 1930 | r = queue_if_no_path(m, false, false, __func__); |
| 1931 | disable_nopath_timeout(m); |
| 1932 | goto out; |
| 1933 | } |
| 1934 | } |
| 1935 | |
| 1936 | if (argc != 2) { |
| 1937 | DMWARN("Invalid multipath message arguments. Expected 2 arguments, got %d.", argc); |
| 1938 | goto out; |
| 1939 | } |
| 1940 | |
| 1941 | if (!strcasecmp(argv[0], "disable_group")) { |
| 1942 | r = bypass_pg_num(m, argv[1], true); |
| 1943 | goto out; |
| 1944 | } else if (!strcasecmp(argv[0], "enable_group")) { |
| 1945 | r = bypass_pg_num(m, argv[1], false); |
| 1946 | goto out; |
| 1947 | } else if (!strcasecmp(argv[0], "switch_group")) { |
| 1948 | r = switch_pg_num(m, argv[1]); |
| 1949 | goto out; |
| 1950 | } else if (!strcasecmp(argv[0], "reinstate_path")) |
| 1951 | action = reinstate_path; |
| 1952 | else if (!strcasecmp(argv[0], "fail_path")) |
| 1953 | action = fail_path; |
| 1954 | else { |
| 1955 | DMWARN("Unrecognised multipath message received: %s", argv[0]); |
| 1956 | goto out; |
| 1957 | } |
| 1958 | |
| 1959 | r = dm_get_device(ti, argv[1], dm_table_get_mode(ti->table), &dev); |
| 1960 | if (r) { |
| 1961 | DMWARN("message: error getting device %s", |
| 1962 | argv[1]); |
| 1963 | goto out; |
| 1964 | } |
| 1965 | |
| 1966 | r = action_dev(m, dev, action); |
| 1967 | |
| 1968 | dm_put_device(ti, dev); |
| 1969 | |
| 1970 | out: |
| 1971 | mutex_unlock(&m->work_mutex); |
| 1972 | return r; |
| 1973 | } |
| 1974 | |
| 1975 | static int multipath_prepare_ioctl(struct dm_target *ti, |
| 1976 | struct block_device **bdev) |
| 1977 | { |
| 1978 | struct multipath *m = ti->private; |
| 1979 | struct pgpath *pgpath; |
| 1980 | unsigned long flags; |
| 1981 | int r; |
| 1982 | |
| 1983 | pgpath = READ_ONCE(m->current_pgpath); |
| 1984 | if (!pgpath || !mpath_double_check_test_bit(MPATHF_QUEUE_IO, m)) |
| 1985 | pgpath = choose_pgpath(m, 0); |
| 1986 | |
| 1987 | if (pgpath) { |
| 1988 | if (!mpath_double_check_test_bit(MPATHF_QUEUE_IO, m)) { |
| 1989 | *bdev = pgpath->path.dev->bdev; |
| 1990 | r = 0; |
| 1991 | } else { |
| 1992 | /* pg_init has not started or completed */ |
| 1993 | r = -ENOTCONN; |
| 1994 | } |
| 1995 | } else { |
| 1996 | /* No path is available */ |
| 1997 | r = -EIO; |
| 1998 | spin_lock_irqsave(&m->lock, flags); |
| 1999 | if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) |
| 2000 | r = -ENOTCONN; |
| 2001 | spin_unlock_irqrestore(&m->lock, flags); |
| 2002 | } |
| 2003 | |
| 2004 | if (r == -ENOTCONN) { |
| 2005 | if (!READ_ONCE(m->current_pg)) { |
| 2006 | /* Path status changed, redo selection */ |
| 2007 | (void) choose_pgpath(m, 0); |
| 2008 | } |
| 2009 | spin_lock_irqsave(&m->lock, flags); |
| 2010 | if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) |
| 2011 | (void) __pg_init_all_paths(m); |
| 2012 | spin_unlock_irqrestore(&m->lock, flags); |
| 2013 | dm_table_run_md_queue_async(m->ti->table); |
| 2014 | process_queued_io_list(m); |
| 2015 | } |
| 2016 | |
| 2017 | /* |
| 2018 | * Only pass ioctls through if the device sizes match exactly. |
| 2019 | */ |
| 2020 | if (!r && ti->len != i_size_read((*bdev)->bd_inode) >> SECTOR_SHIFT) |
| 2021 | return 1; |
| 2022 | return r; |
| 2023 | } |
| 2024 | |
| 2025 | static int multipath_iterate_devices(struct dm_target *ti, |
| 2026 | iterate_devices_callout_fn fn, void *data) |
| 2027 | { |
| 2028 | struct multipath *m = ti->private; |
| 2029 | struct priority_group *pg; |
| 2030 | struct pgpath *p; |
| 2031 | int ret = 0; |
| 2032 | |
| 2033 | list_for_each_entry(pg, &m->priority_groups, list) { |
| 2034 | list_for_each_entry(p, &pg->pgpaths, list) { |
| 2035 | ret = fn(ti, p->path.dev, ti->begin, ti->len, data); |
| 2036 | if (ret) |
| 2037 | goto out; |
| 2038 | } |
| 2039 | } |
| 2040 | |
| 2041 | out: |
| 2042 | return ret; |
| 2043 | } |
| 2044 | |
| 2045 | static int pgpath_busy(struct pgpath *pgpath) |
| 2046 | { |
| 2047 | struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev); |
| 2048 | |
| 2049 | return blk_lld_busy(q); |
| 2050 | } |
| 2051 | |
| 2052 | /* |
| 2053 | * We return "busy", only when we can map I/Os but underlying devices |
| 2054 | * are busy (so even if we map I/Os now, the I/Os will wait on |
| 2055 | * the underlying queue). |
| 2056 | * In other words, if we want to kill I/Os or queue them inside us |
| 2057 | * due to map unavailability, we don't return "busy". Otherwise, |
| 2058 | * dm core won't give us the I/Os and we can't do what we want. |
| 2059 | */ |
| 2060 | static int multipath_busy(struct dm_target *ti) |
| 2061 | { |
| 2062 | bool busy = false, has_active = false; |
| 2063 | struct multipath *m = ti->private; |
| 2064 | struct priority_group *pg, *next_pg; |
| 2065 | struct pgpath *pgpath; |
| 2066 | |
| 2067 | /* pg_init in progress */ |
| 2068 | if (atomic_read(&m->pg_init_in_progress)) |
| 2069 | return true; |
| 2070 | |
| 2071 | /* no paths available, for blk-mq: rely on IO mapping to delay requeue */ |
| 2072 | if (!atomic_read(&m->nr_valid_paths)) { |
| 2073 | unsigned long flags; |
| 2074 | spin_lock_irqsave(&m->lock, flags); |
| 2075 | if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) { |
| 2076 | spin_unlock_irqrestore(&m->lock, flags); |
| 2077 | return (m->queue_mode != DM_TYPE_REQUEST_BASED); |
| 2078 | } |
| 2079 | spin_unlock_irqrestore(&m->lock, flags); |
| 2080 | } |
| 2081 | |
| 2082 | /* Guess which priority_group will be used at next mapping time */ |
| 2083 | pg = READ_ONCE(m->current_pg); |
| 2084 | next_pg = READ_ONCE(m->next_pg); |
| 2085 | if (unlikely(!READ_ONCE(m->current_pgpath) && next_pg)) |
| 2086 | pg = next_pg; |
| 2087 | |
| 2088 | if (!pg) { |
| 2089 | /* |
| 2090 | * We don't know which pg will be used at next mapping time. |
| 2091 | * We don't call choose_pgpath() here to avoid to trigger |
| 2092 | * pg_init just by busy checking. |
| 2093 | * So we don't know whether underlying devices we will be using |
| 2094 | * at next mapping time are busy or not. Just try mapping. |
| 2095 | */ |
| 2096 | return busy; |
| 2097 | } |
| 2098 | |
| 2099 | /* |
| 2100 | * If there is one non-busy active path at least, the path selector |
| 2101 | * will be able to select it. So we consider such a pg as not busy. |
| 2102 | */ |
| 2103 | busy = true; |
| 2104 | list_for_each_entry(pgpath, &pg->pgpaths, list) { |
| 2105 | if (pgpath->is_active) { |
| 2106 | has_active = true; |
| 2107 | if (!pgpath_busy(pgpath)) { |
| 2108 | busy = false; |
| 2109 | break; |
| 2110 | } |
| 2111 | } |
| 2112 | } |
| 2113 | |
| 2114 | if (!has_active) { |
| 2115 | /* |
| 2116 | * No active path in this pg, so this pg won't be used and |
| 2117 | * the current_pg will be changed at next mapping time. |
| 2118 | * We need to try mapping to determine it. |
| 2119 | */ |
| 2120 | busy = false; |
| 2121 | } |
| 2122 | |
| 2123 | return busy; |
| 2124 | } |
| 2125 | |
| 2126 | /*----------------------------------------------------------------- |
| 2127 | * Module setup |
| 2128 | *---------------------------------------------------------------*/ |
| 2129 | static struct target_type multipath_target = { |
| 2130 | .name = "multipath", |
| 2131 | .version = {1, 14, 0}, |
| 2132 | .features = DM_TARGET_SINGLETON | DM_TARGET_IMMUTABLE | |
| 2133 | DM_TARGET_PASSES_INTEGRITY, |
| 2134 | .module = THIS_MODULE, |
| 2135 | .ctr = multipath_ctr, |
| 2136 | .dtr = multipath_dtr, |
| 2137 | .clone_and_map_rq = multipath_clone_and_map, |
| 2138 | .release_clone_rq = multipath_release_clone, |
| 2139 | .rq_end_io = multipath_end_io, |
| 2140 | .map = multipath_map_bio, |
| 2141 | .end_io = multipath_end_io_bio, |
| 2142 | .presuspend = multipath_presuspend, |
| 2143 | .postsuspend = multipath_postsuspend, |
| 2144 | .resume = multipath_resume, |
| 2145 | .status = multipath_status, |
| 2146 | .message = multipath_message, |
| 2147 | .prepare_ioctl = multipath_prepare_ioctl, |
| 2148 | .iterate_devices = multipath_iterate_devices, |
| 2149 | .busy = multipath_busy, |
| 2150 | }; |
| 2151 | |
| 2152 | static int __init dm_multipath_init(void) |
| 2153 | { |
| 2154 | int r; |
| 2155 | |
| 2156 | kmultipathd = alloc_workqueue("kmpathd", WQ_MEM_RECLAIM, 0); |
| 2157 | if (!kmultipathd) { |
| 2158 | DMERR("failed to create workqueue kmpathd"); |
| 2159 | r = -ENOMEM; |
| 2160 | goto bad_alloc_kmultipathd; |
| 2161 | } |
| 2162 | |
| 2163 | /* |
| 2164 | * A separate workqueue is used to handle the device handlers |
| 2165 | * to avoid overloading existing workqueue. Overloading the |
| 2166 | * old workqueue would also create a bottleneck in the |
| 2167 | * path of the storage hardware device activation. |
| 2168 | */ |
| 2169 | kmpath_handlerd = alloc_ordered_workqueue("kmpath_handlerd", |
| 2170 | WQ_MEM_RECLAIM); |
| 2171 | if (!kmpath_handlerd) { |
| 2172 | DMERR("failed to create workqueue kmpath_handlerd"); |
| 2173 | r = -ENOMEM; |
| 2174 | goto bad_alloc_kmpath_handlerd; |
| 2175 | } |
| 2176 | |
| 2177 | r = dm_register_target(&multipath_target); |
| 2178 | if (r < 0) { |
| 2179 | DMERR("request-based register failed %d", r); |
| 2180 | r = -EINVAL; |
| 2181 | goto bad_register_target; |
| 2182 | } |
| 2183 | |
| 2184 | return 0; |
| 2185 | |
| 2186 | bad_register_target: |
| 2187 | destroy_workqueue(kmpath_handlerd); |
| 2188 | bad_alloc_kmpath_handlerd: |
| 2189 | destroy_workqueue(kmultipathd); |
| 2190 | bad_alloc_kmultipathd: |
| 2191 | return r; |
| 2192 | } |
| 2193 | |
| 2194 | static void __exit dm_multipath_exit(void) |
| 2195 | { |
| 2196 | destroy_workqueue(kmpath_handlerd); |
| 2197 | destroy_workqueue(kmultipathd); |
| 2198 | |
| 2199 | dm_unregister_target(&multipath_target); |
| 2200 | } |
| 2201 | |
| 2202 | module_init(dm_multipath_init); |
| 2203 | module_exit(dm_multipath_exit); |
| 2204 | |
| 2205 | module_param_named(queue_if_no_path_timeout_secs, |
| 2206 | queue_if_no_path_timeout_secs, ulong, S_IRUGO | S_IWUSR); |
| 2207 | MODULE_PARM_DESC(queue_if_no_path_timeout_secs, "No available paths queue IO timeout in seconds"); |
| 2208 | |
| 2209 | MODULE_DESCRIPTION(DM_NAME " multipath target"); |
| 2210 | MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>"); |
| 2211 | MODULE_LICENSE("GPL"); |