block/blk-sysfs.c

   1 /*
   2  * Functions related to sysfs handling
   3  */
   4 #include <linux/kernel.h>
   5 #include <linux/slab.h>
   6 #include <linux/module.h>
   7 #include <linux/bio.h>
   8 #include <linux/blkdev.h>
   9 #include <linux/backing-dev.h>
  10 #include <linux/blktrace_api.h>
  11 #include <linux/blk-mq.h>
  12 #include <linux/blk-cgroup.h>
  13
  14 #include "blk.h"
  15 #include "blk-mq.h"
  16
  17 struct queue_sysfs_entry {
  18         struct attribute attr;
  19         ssize_t (*show)(struct request_queue *, char *);
  20         ssize_t (*store)(struct request_queue *, const char *, size_t);
  21 };
  22
  23 static ssize_t
  24 queue_var_show(unsigned long var, char *page)
  25 {
  26         return sprintf(page, "%lu\n", var);
  27 }
  28
  29 static ssize_t
  30 queue_var_store(unsigned long *var, const char *page, size_t count)
  31 {
  32         int err;
  33         unsigned long v;
  34
  35         err = kstrtoul(page, 10, &v);
  36         if (err || v > UINT_MAX)
  37                 return -EINVAL;
  38
  39         *var = v;
  40
  41         return count;
  42 }
  43
  44 static ssize_t queue_requests_show(struct request_queue *q, char *page)
  45 {
  46         return queue_var_show(q->nr_requests, (page));
  47 }
  48
  49 static ssize_t
  50 queue_requests_store(struct request_queue *q, const char *page, size_t count)
  51 {
  52         unsigned long nr;
  53         int ret, err;
  54
  55         if (!q->request_fn && !q->mq_ops)
  56                 return -EINVAL;
  57
  58         ret = queue_var_store(&nr, page, count);
  59         if (ret < 0)
  60                 return ret;
  61
  62         if (nr < BLKDEV_MIN_RQ)
  63                 nr = BLKDEV_MIN_RQ;
  64
  65         if (q->request_fn)
  66                 err = blk_update_nr_requests(q, nr);
  67         else
  68                 err = blk_mq_update_nr_requests(q, nr);
  69
  70         if (err)
  71                 return err;
  72
  73         return ret;
  74 }
  75
  76 static ssize_t queue_ra_show(struct request_queue *q, char *page)
  77 {
  78         unsigned long ra_kb = q->backing_dev_info.ra_pages <<
  79                                         (PAGE_SHIFT - 10);
  80
  81         return queue_var_show(ra_kb, (page));
  82 }
  83
  84 static ssize_t
  85 queue_ra_store(struct request_queue *q, const char *page, size_t count)
  86 {
  87         unsigned long ra_kb;
  88         ssize_t ret = queue_var_store(&ra_kb, page, count);
  89
  90         if (ret < 0)
  91                 return ret;
  92
  93         q->backing_dev_info.ra_pages = ra_kb >> (PAGE_SHIFT - 10);
  94
  95         return ret;
  96 }
  97
  98 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
  99 {
 100         int max_sectors_kb = queue_max_sectors(q) >> 1;
 101
 102         return queue_var_show(max_sectors_kb, (page));
 103 }
 104
 105 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
 106 {
 107         return queue_var_show(queue_max_segments(q), (page));
 108 }
 109
 110 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
 111 {
 112         return queue_var_show(q->limits.max_integrity_segments, (page));
 113 }
 114
 115 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 116 {
 117         if (blk_queue_cluster(q))
 118                 return queue_var_show(queue_max_segment_size(q), (page));
 119
 120         return queue_var_show(PAGE_SIZE, (page));
 121 }
 122
 123 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 124 {
 125         return queue_var_show(queue_logical_block_size(q), page);
 126 }
 127
 128 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 129 {
 130         return queue_var_show(queue_physical_block_size(q), page);
 131 }
 132
 133 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 134 {
 135         return queue_var_show(queue_io_min(q), page);
 136 }
 137
 138 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 139 {
 140         return queue_var_show(queue_io_opt(q), page);
 141 }
 142
 143 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 144 {
 145         return queue_var_show(q->limits.discard_granularity, page);
 146 }
 147
 148 static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
 149 {
 150
 151         return sprintf(page, "%llu\n",
 152                 (unsigned long long)q->limits.max_hw_discard_sectors << 9);
 153 }
 154
 155 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 156 {
 157         return sprintf(page, "%llu\n",
 158                        (unsigned long long)q->limits.max_discard_sectors << 9);
 159 }
 160
 161 static ssize_t queue_discard_max_store(struct request_queue *q,
 162                                        const char *page, size_t count)
 163 {
 164         unsigned long max_discard;
 165         ssize_t ret = queue_var_store(&max_discard, page, count);
 166
 167         if (ret < 0)
 168                 return ret;
 169
 170         if (max_discard & (q->limits.discard_granularity - 1))
 171                 return -EINVAL;
 172
 173         max_discard >>= 9;
 174         if (max_discard > UINT_MAX)
 175                 return -EINVAL;
 176
 177         if (max_discard > q->limits.max_hw_discard_sectors)
 178                 max_discard = q->limits.max_hw_discard_sectors;
 179
 180         q->limits.max_discard_sectors = max_discard;
 181         return ret;
 182 }
 183
 184 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 185 {
 186         return queue_var_show(queue_discard_zeroes_data(q), page);
 187 }
 188
 189 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
 190 {
 191         return sprintf(page, "%llu\n",
 192                 (unsigned long long)q->limits.max_write_same_sectors << 9);
 193 }
 194
 195
 196 static ssize_t
 197 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 198 {
 199         unsigned long max_sectors_kb,
 200                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 201                         page_kb = 1 << (PAGE_SHIFT - 10);
 202         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 203
 204         if (ret < 0)
 205                 return ret;
 206
 207         max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, (unsigned long)
 208                                          q->limits.max_dev_sectors >> 1);
 209
 210         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 211                 return -EINVAL;
 212
 213         spin_lock_irq(q->queue_lock);
 214         q->limits.max_sectors = max_sectors_kb << 1;
 215         spin_unlock_irq(q->queue_lock);
 216
 217         return ret;
 218 }
 219
 220 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 221 {
 222         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 223
 224         return queue_var_show(max_hw_sectors_kb, (page));
 225 }
 226
 227 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 228 static ssize_t                                                          \
 229 queue_show_##name(struct request_queue *q, char *page)                  \
 230 {                                                                       \
 231         int bit;                                                        \
 232         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 233         return queue_var_show(neg ? !bit : bit, page);                  \
 234 }                                                                       \
 235 static ssize_t                                                          \
 236 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
 237 {                                                                       \
 238         unsigned long val;                                              \
 239         ssize_t ret;                                                    \
 240         ret = queue_var_store(&val, page, count);                       \
 241         if (ret < 0)                                                    \
 242                  return ret;                                            \
 243         if (neg)                                                        \
 244                 val = !val;                                             \
 245                                                                         \
 246         spin_lock_irq(q->queue_lock);                                   \
 247         if (val)                                                        \
 248                 queue_flag_set(QUEUE_FLAG_##flag, q);                   \
 249         else                                                            \
 250                 queue_flag_clear(QUEUE_FLAG_##flag, q);                 \
 251         spin_unlock_irq(q->queue_lock);                                 \
 252         return ret;                                                     \
 253 }
 254
 255 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 256 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 257 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 258 #undef QUEUE_SYSFS_BIT_FNS
 259
 260 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 261 {
 262         return queue_var_show((blk_queue_nomerges(q) << 1) |
 263                                blk_queue_noxmerges(q), page);
 264 }
 265
 266 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 267                                     size_t count)
 268 {
 269         unsigned long nm;
 270         ssize_t ret = queue_var_store(&nm, page, count);
 271
 272         if (ret < 0)
 273                 return ret;
 274
 275         spin_lock_irq(q->queue_lock);
 276         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 277         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 278         if (nm == 2)
 279                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 280         else if (nm)
 281                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 282         spin_unlock_irq(q->queue_lock);
 283
 284         return ret;
 285 }
 286
 287 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 288 {
 289         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 290         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 291
 292         return queue_var_show(set << force, page);
 293 }
 294
 295 static ssize_t
 296 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 297 {
 298         ssize_t ret = -EINVAL;
 299 #ifdef CONFIG_SMP
 300         unsigned long val;
 301
 302         ret = queue_var_store(&val, page, count);
 303         if (ret < 0)
 304                 return ret;
 305
 306         spin_lock_irq(q->queue_lock);
 307         if (val == 2) {
 308                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 309                 queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 310         } else if (val == 1) {
 311                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 312                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 313         } else if (val == 0) {
 314                 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 315                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 316         }
 317         spin_unlock_irq(q->queue_lock);
 318 #endif
 319         return ret;
 320 }
 321
 322 static ssize_t queue_poll_show(struct request_queue *q, char *page)
 323 {
 324         return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
 325 }
 326
 327 static ssize_t queue_poll_store(struct request_queue *q, const char *page,
 328                                 size_t count)
 329 {
 330         unsigned long poll_on;
 331         ssize_t ret;
 332
 333         if (!q->mq_ops || !q->mq_ops->poll)
 334                 return -EINVAL;
 335
 336         ret = queue_var_store(&poll_on, page, count);
 337         if (ret < 0)
 338                 return ret;
 339
 340         spin_lock_irq(q->queue_lock);
 341         if (poll_on)
 342                 queue_flag_set(QUEUE_FLAG_POLL, q);
 343         else
 344                 queue_flag_clear(QUEUE_FLAG_POLL, q);
 345         spin_unlock_irq(q->queue_lock);
 346
 347         return ret;
 348 }
 349
 350 static struct queue_sysfs_entry queue_requests_entry = {
 351         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 352         .show = queue_requests_show,
 353         .store = queue_requests_store,
 354 };
 355
 356 static struct queue_sysfs_entry queue_ra_entry = {
 357         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 358         .show = queue_ra_show,
 359         .store = queue_ra_store,
 360 };
 361
 362 static struct queue_sysfs_entry queue_max_sectors_entry = {
 363         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 364         .show = queue_max_sectors_show,
 365         .store = queue_max_sectors_store,
 366 };
 367
 368 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 369         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 370         .show = queue_max_hw_sectors_show,
 371 };
 372
 373 static struct queue_sysfs_entry queue_max_segments_entry = {
 374         .attr = {.name = "max_segments", .mode = S_IRUGO },
 375         .show = queue_max_segments_show,
 376 };
 377
 378 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
 379         .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
 380         .show = queue_max_integrity_segments_show,
 381 };
 382
 383 static struct queue_sysfs_entry queue_max_segment_size_entry = {
 384         .attr = {.name = "max_segment_size", .mode = S_IRUGO },
 385         .show = queue_max_segment_size_show,
 386 };
 387
 388 static struct queue_sysfs_entry queue_iosched_entry = {
 389         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 390         .show = elv_iosched_show,
 391         .store = elv_iosched_store,
 392 };
 393
 394 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 395         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 396         .show = queue_logical_block_size_show,
 397 };
 398
 399 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 400         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 401         .show = queue_logical_block_size_show,
 402 };
 403
 404 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 405         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 406         .show = queue_physical_block_size_show,
 407 };
 408
 409 static struct queue_sysfs_entry queue_io_min_entry = {
 410         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 411         .show = queue_io_min_show,
 412 };
 413
 414 static struct queue_sysfs_entry queue_io_opt_entry = {
 415         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 416         .show = queue_io_opt_show,
 417 };
 418
 419 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 420         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
 421         .show = queue_discard_granularity_show,
 422 };
 423
 424 static struct queue_sysfs_entry queue_discard_max_hw_entry = {
 425         .attr = {.name = "discard_max_hw_bytes", .mode = S_IRUGO },
 426         .show = queue_discard_max_hw_show,
 427 };
 428
 429 static struct queue_sysfs_entry queue_discard_max_entry = {
 430         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO | S_IWUSR },
 431         .show = queue_discard_max_show,
 432         .store = queue_discard_max_store,
 433 };
 434
 435 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 436         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
 437         .show = queue_discard_zeroes_data_show,
 438 };
 439
 440 static struct queue_sysfs_entry queue_write_same_max_entry = {
 441         .attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
 442         .show = queue_write_same_max_show,
 443 };
 444
 445 static struct queue_sysfs_entry queue_nonrot_entry = {
 446         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 447         .show = queue_show_nonrot,
 448         .store = queue_store_nonrot,
 449 };
 450
 451 static struct queue_sysfs_entry queue_nomerges_entry = {
 452         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 453         .show = queue_nomerges_show,
 454         .store = queue_nomerges_store,
 455 };
 456
 457 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 458         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 459         .show = queue_rq_affinity_show,
 460         .store = queue_rq_affinity_store,
 461 };
 462
 463 static struct queue_sysfs_entry queue_iostats_entry = {
 464         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 465         .show = queue_show_iostats,
 466         .store = queue_store_iostats,
 467 };
 468
 469 static struct queue_sysfs_entry queue_random_entry = {
 470         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
 471         .show = queue_show_random,
 472         .store = queue_store_random,
 473 };
 474
 475 static struct queue_sysfs_entry queue_poll_entry = {
 476         .attr = {.name = "io_poll", .mode = S_IRUGO | S_IWUSR },
 477         .show = queue_poll_show,
 478         .store = queue_poll_store,
 479 };
 480
 481 static struct attribute *default_attrs[] = {
 482         &queue_requests_entry.attr,
 483         &queue_ra_entry.attr,
 484         &queue_max_hw_sectors_entry.attr,
 485         &queue_max_sectors_entry.attr,
 486         &queue_max_segments_entry.attr,
 487         &queue_max_integrity_segments_entry.attr,
 488         &queue_max_segment_size_entry.attr,
 489         &queue_iosched_entry.attr,
 490         &queue_hw_sector_size_entry.attr,
 491         &queue_logical_block_size_entry.attr,
 492         &queue_physical_block_size_entry.attr,
 493         &queue_io_min_entry.attr,
 494         &queue_io_opt_entry.attr,
 495         &queue_discard_granularity_entry.attr,
 496         &queue_discard_max_entry.attr,
 497         &queue_discard_max_hw_entry.attr,
 498         &queue_discard_zeroes_data_entry.attr,
 499         &queue_write_same_max_entry.attr,
 500         &queue_nonrot_entry.attr,
 501         &queue_nomerges_entry.attr,
 502         &queue_rq_affinity_entry.attr,
 503         &queue_iostats_entry.attr,
 504         &queue_random_entry.attr,
 505         &queue_poll_entry.attr,
 506         NULL,
 507 };
 508
 509 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 510
 511 static ssize_t
 512 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 513 {
 514         struct queue_sysfs_entry *entry = to_queue(attr);
 515         struct request_queue *q =
 516                 container_of(kobj, struct request_queue, kobj);
 517         ssize_t res;
 518
 519         if (!entry->show)
 520                 return -EIO;
 521         mutex_lock(&q->sysfs_lock);
 522         if (blk_queue_dying(q)) {
 523                 mutex_unlock(&q->sysfs_lock);
 524                 return -ENOENT;
 525         }
 526         res = entry->show(q, page);
 527         mutex_unlock(&q->sysfs_lock);
 528         return res;
 529 }
 530
 531 static ssize_t
 532 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 533                     const char *page, size_t length)
 534 {
 535         struct queue_sysfs_entry *entry = to_queue(attr);
 536         struct request_queue *q;
 537         ssize_t res;
 538
 539         if (!entry->store)
 540                 return -EIO;
 541
 542         q = container_of(kobj, struct request_queue, kobj);
 543         mutex_lock(&q->sysfs_lock);
 544         if (blk_queue_dying(q)) {
 545                 mutex_unlock(&q->sysfs_lock);
 546                 return -ENOENT;
 547         }
 548         res = entry->store(q, page, length);
 549         mutex_unlock(&q->sysfs_lock);
 550         return res;
 551 }
 552
 553 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 554 {
 555         struct request_queue *q = container_of(rcu_head, struct request_queue,
 556                                                rcu_head);
 557         kmem_cache_free(blk_requestq_cachep, q);
 558 }
 559
 560 /**
 561  * blk_release_queue: - release a &struct request_queue when it is no longer needed
 562  * @kobj:    the kobj belonging to the request queue to be released
 563  *
 564  * Description:
 565  *     blk_release_queue is the pair to blk_init_queue() or
 566  *     blk_queue_make_request().  It should be called when a request queue is
 567  *     being released; typically when a block device is being de-registered.
 568  *     Currently, its primary task it to free all the &struct request
 569  *     structures that were allocated to the queue and the queue itself.
 570  *
 571  * Note:
 572  *     The low level driver must have finished any outstanding requests first
 573  *     via blk_cleanup_queue().
 574  **/
 575 static void blk_release_queue(struct kobject *kobj)
 576 {
 577         struct request_queue *q =
 578                 container_of(kobj, struct request_queue, kobj);
 579
 580         bdi_exit(&q->backing_dev_info);
 581         blkcg_exit_queue(q);
 582
 583         if (q->elevator) {
 584                 spin_lock_irq(q->queue_lock);
 585                 ioc_clear_queue(q);
 586                 spin_unlock_irq(q->queue_lock);
 587                 elevator_exit(q->elevator);
 588         }
 589
 590         blk_exit_rl(&q->root_rl);
 591
 592         if (q->queue_tags)
 593                 __blk_queue_free_tags(q);
 594
 595         if (!q->mq_ops)
 596                 blk_free_flush_queue(q->fq);
 597         else
 598                 blk_mq_release(q);
 599
 600         blk_trace_shutdown(q);
 601
 602         if (q->bio_split)
 603                 bioset_free(q->bio_split);
 604
 605         ida_simple_remove(&blk_queue_ida, q->id);
 606         call_rcu(&q->rcu_head, blk_free_queue_rcu);
 607 }
 608
 609 static const struct sysfs_ops queue_sysfs_ops = {
 610         .show   = queue_attr_show,
 611         .store  = queue_attr_store,
 612 };
 613
 614 struct kobj_type blk_queue_ktype = {
 615         .sysfs_ops      = &queue_sysfs_ops,
 616         .default_attrs  = default_attrs,
 617         .release        = blk_release_queue,
 618 };
 619
 620 int blk_register_queue(struct gendisk *disk)
 621 {
 622         int ret;
 623         struct device *dev = disk_to_dev(disk);
 624         struct request_queue *q = disk->queue;
 625
 626         if (WARN_ON(!q))
 627                 return -ENXIO;
 628
 629         /*
 630          * SCSI probing may synchronously create and destroy a lot of
 631          * request_queues for non-existent devices.  Shutting down a fully
 632          * functional queue takes measureable wallclock time as RCU grace
 633          * periods are involved.  To avoid excessive latency in these
 634          * cases, a request_queue starts out in a degraded mode which is
 635          * faster to shut down and is made fully functional here as
 636          * request_queues for non-existent devices never get registered.
 637          */
 638         if (!blk_queue_init_done(q)) {
 639                 queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
 640                 percpu_ref_switch_to_percpu(&q->q_usage_counter);
 641                 blk_queue_bypass_end(q);
 642         }
 643
 644         ret = blk_trace_init_sysfs(dev);
 645         if (ret)
 646                 return ret;
 647
 648         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 649         if (ret < 0) {
 650                 blk_trace_remove_sysfs(dev);
 651                 return ret;
 652         }
 653
 654         kobject_uevent(&q->kobj, KOBJ_ADD);
 655
 656         if (q->mq_ops)
 657                 blk_mq_register_disk(disk);
 658
 659         if (!q->request_fn)
 660                 return 0;
 661
 662         ret = elv_register_queue(q);
 663         if (ret) {
 664                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 665                 kobject_del(&q->kobj);
 666                 blk_trace_remove_sysfs(dev);
 667                 kobject_put(&dev->kobj);
 668                 return ret;
 669         }
 670
 671         return 0;
 672 }
 673
 674 void blk_unregister_queue(struct gendisk *disk)
 675 {
 676         struct request_queue *q = disk->queue;
 677
 678         if (WARN_ON(!q))
 679                 return;
 680
 681         if (q->mq_ops)
 682                 blk_mq_unregister_disk(disk);
 683
 684         if (q->request_fn)
 685                 elv_unregister_queue(q);
 686
 687         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 688         kobject_del(&q->kobj);
 689         blk_trace_remove_sysfs(disk_to_dev(disk));
 690         kobject_put(&disk_to_dev(disk)->kobj);
 691 }