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_CACHE_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_CACHE_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_CACHE_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         unsigned long long val;
 151
 152         val = q->limits.max_hw_discard_sectors << 9;
 153         return sprintf(page, "%llu\n", val);
 154 }
 155
 156 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 157 {
 158         return sprintf(page, "%llu\n",
 159                        (unsigned long long)q->limits.max_discard_sectors << 9);
 160 }
 161
 162 static ssize_t queue_discard_max_store(struct request_queue *q,
 163                                        const char *page, size_t count)
 164 {
 165         unsigned long max_discard;
 166         ssize_t ret = queue_var_store(&max_discard, page, count);
 167
 168         if (ret < 0)
 169                 return ret;
 170
 171         if (max_discard & (q->limits.discard_granularity - 1))
 172                 return -EINVAL;
 173
 174         max_discard >>= 9;
 175         if (max_discard > UINT_MAX)
 176                 return -EINVAL;
 177
 178         if (max_discard > q->limits.max_hw_discard_sectors)
 179                 max_discard = q->limits.max_hw_discard_sectors;
 180
 181         q->limits.max_discard_sectors = max_discard;
 182         return ret;
 183 }
 184
 185 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 186 {
 187         return queue_var_show(queue_discard_zeroes_data(q), page);
 188 }
 189
 190 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
 191 {
 192         return sprintf(page, "%llu\n",
 193                 (unsigned long long)q->limits.max_write_same_sectors << 9);
 194 }
 195
 196
 197 static ssize_t
 198 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 199 {
 200         unsigned long max_sectors_kb,
 201                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 202                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
 203         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 204
 205         if (ret < 0)
 206                 return ret;
 207
 208         max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, (unsigned long)
 209                                          q->limits.max_dev_sectors >> 1);
 210
 211         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 212                 return -EINVAL;
 213
 214         spin_lock_irq(q->queue_lock);
 215         q->limits.max_sectors = max_sectors_kb << 1;
 216         q->backing_dev_info->io_pages = max_sectors_kb >> (PAGE_SHIFT - 10);
 217         spin_unlock_irq(q->queue_lock);
 218
 219         return ret;
 220 }
 221
 222 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 223 {
 224         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 225
 226         return queue_var_show(max_hw_sectors_kb, (page));
 227 }
 228
 229 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 230 static ssize_t                                                          \
 231 queue_show_##name(struct request_queue *q, char *page)                  \
 232 {                                                                       \
 233         int bit;                                                        \
 234         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 235         return queue_var_show(neg ? !bit : bit, page);                  \
 236 }                                                                       \
 237 static ssize_t                                                          \
 238 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
 239 {                                                                       \
 240         unsigned long val;                                              \
 241         ssize_t ret;                                                    \
 242         ret = queue_var_store(&val, page, count);                       \
 243         if (ret < 0)                                                    \
 244                  return ret;                                            \
 245         if (neg)                                                        \
 246                 val = !val;                                             \
 247                                                                         \
 248         spin_lock_irq(q->queue_lock);                                   \
 249         if (val)                                                        \
 250                 queue_flag_set(QUEUE_FLAG_##flag, q);                   \
 251         else                                                            \
 252                 queue_flag_clear(QUEUE_FLAG_##flag, q);                 \
 253         spin_unlock_irq(q->queue_lock);                                 \
 254         return ret;                                                     \
 255 }
 256
 257 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 258 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 259 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 260 #undef QUEUE_SYSFS_BIT_FNS
 261
 262 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 263 {
 264         return queue_var_show((blk_queue_nomerges(q) << 1) |
 265                                blk_queue_noxmerges(q), page);
 266 }
 267
 268 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 269                                     size_t count)
 270 {
 271         unsigned long nm;
 272         ssize_t ret = queue_var_store(&nm, page, count);
 273
 274         if (ret < 0)
 275                 return ret;
 276
 277         spin_lock_irq(q->queue_lock);
 278         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 279         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 280         if (nm == 2)
 281                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 282         else if (nm)
 283                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 284         spin_unlock_irq(q->queue_lock);
 285
 286         return ret;
 287 }
 288
 289 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 290 {
 291         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 292         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 293
 294         return queue_var_show(set << force, page);
 295 }
 296
 297 static ssize_t
 298 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 299 {
 300         ssize_t ret = -EINVAL;
 301 #ifdef CONFIG_SMP
 302         unsigned long val;
 303
 304         ret = queue_var_store(&val, page, count);
 305         if (ret < 0)
 306                 return ret;
 307
 308         spin_lock_irq(q->queue_lock);
 309         if (val == 2) {
 310                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 311                 queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 312         } else if (val == 1) {
 313                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 314                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 315         } else if (val == 0) {
 316                 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 317                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 318         }
 319         spin_unlock_irq(q->queue_lock);
 320 #endif
 321         return ret;
 322 }
 323
 324 static ssize_t queue_poll_show(struct request_queue *q, char *page)
 325 {
 326         return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
 327 }
 328
 329 static ssize_t queue_poll_store(struct request_queue *q, const char *page,
 330                                 size_t count)
 331 {
 332         unsigned long poll_on;
 333         ssize_t ret;
 334
 335         if (!q->mq_ops || !q->mq_ops->poll)
 336                 return -EINVAL;
 337
 338         ret = queue_var_store(&poll_on, page, count);
 339         if (ret < 0)
 340                 return ret;
 341
 342         spin_lock_irq(q->queue_lock);
 343         if (poll_on)
 344                 queue_flag_set(QUEUE_FLAG_POLL, q);
 345         else
 346                 queue_flag_clear(QUEUE_FLAG_POLL, q);
 347         spin_unlock_irq(q->queue_lock);
 348
 349         return ret;
 350 }
 351
 352 static struct queue_sysfs_entry queue_requests_entry = {
 353         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 354         .show = queue_requests_show,
 355         .store = queue_requests_store,
 356 };
 357
 358 static struct queue_sysfs_entry queue_ra_entry = {
 359         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 360         .show = queue_ra_show,
 361         .store = queue_ra_store,
 362 };
 363
 364 static struct queue_sysfs_entry queue_max_sectors_entry = {
 365         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 366         .show = queue_max_sectors_show,
 367         .store = queue_max_sectors_store,
 368 };
 369
 370 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 371         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 372         .show = queue_max_hw_sectors_show,
 373 };
 374
 375 static struct queue_sysfs_entry queue_max_segments_entry = {
 376         .attr = {.name = "max_segments", .mode = S_IRUGO },
 377         .show = queue_max_segments_show,
 378 };
 379
 380 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
 381         .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
 382         .show = queue_max_integrity_segments_show,
 383 };
 384
 385 static struct queue_sysfs_entry queue_max_segment_size_entry = {
 386         .attr = {.name = "max_segment_size", .mode = S_IRUGO },
 387         .show = queue_max_segment_size_show,
 388 };
 389
 390 static struct queue_sysfs_entry queue_iosched_entry = {
 391         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 392         .show = elv_iosched_show,
 393         .store = elv_iosched_store,
 394 };
 395
 396 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 397         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 398         .show = queue_logical_block_size_show,
 399 };
 400
 401 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 402         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 403         .show = queue_logical_block_size_show,
 404 };
 405
 406 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 407         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 408         .show = queue_physical_block_size_show,
 409 };
 410
 411 static struct queue_sysfs_entry queue_io_min_entry = {
 412         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 413         .show = queue_io_min_show,
 414 };
 415
 416 static struct queue_sysfs_entry queue_io_opt_entry = {
 417         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 418         .show = queue_io_opt_show,
 419 };
 420
 421 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 422         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
 423         .show = queue_discard_granularity_show,
 424 };
 425
 426 static struct queue_sysfs_entry queue_discard_max_hw_entry = {
 427         .attr = {.name = "discard_max_hw_bytes", .mode = S_IRUGO },
 428         .show = queue_discard_max_hw_show,
 429 };
 430
 431 static struct queue_sysfs_entry queue_discard_max_entry = {
 432         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO | S_IWUSR },
 433         .show = queue_discard_max_show,
 434         .store = queue_discard_max_store,
 435 };
 436
 437 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 438         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
 439         .show = queue_discard_zeroes_data_show,
 440 };
 441
 442 static struct queue_sysfs_entry queue_write_same_max_entry = {
 443         .attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
 444         .show = queue_write_same_max_show,
 445 };
 446
 447 static struct queue_sysfs_entry queue_nonrot_entry = {
 448         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 449         .show = queue_show_nonrot,
 450         .store = queue_store_nonrot,
 451 };
 452
 453 static struct queue_sysfs_entry queue_nomerges_entry = {
 454         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 455         .show = queue_nomerges_show,
 456         .store = queue_nomerges_store,
 457 };
 458
 459 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 460         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 461         .show = queue_rq_affinity_show,
 462         .store = queue_rq_affinity_store,
 463 };
 464
 465 static struct queue_sysfs_entry queue_iostats_entry = {
 466         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 467         .show = queue_show_iostats,
 468         .store = queue_store_iostats,
 469 };
 470
 471 static struct queue_sysfs_entry queue_random_entry = {
 472         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
 473         .show = queue_show_random,
 474         .store = queue_store_random,
 475 };
 476
 477 static struct queue_sysfs_entry queue_poll_entry = {
 478         .attr = {.name = "io_poll", .mode = S_IRUGO | S_IWUSR },
 479         .show = queue_poll_show,
 480         .store = queue_poll_store,
 481 };
 482
 483 static struct attribute *default_attrs[] = {
 484         &queue_requests_entry.attr,
 485         &queue_ra_entry.attr,
 486         &queue_max_hw_sectors_entry.attr,
 487         &queue_max_sectors_entry.attr,
 488         &queue_max_segments_entry.attr,
 489         &queue_max_integrity_segments_entry.attr,
 490         &queue_max_segment_size_entry.attr,
 491         &queue_iosched_entry.attr,
 492         &queue_hw_sector_size_entry.attr,
 493         &queue_logical_block_size_entry.attr,
 494         &queue_physical_block_size_entry.attr,
 495         &queue_io_min_entry.attr,
 496         &queue_io_opt_entry.attr,
 497         &queue_discard_granularity_entry.attr,
 498         &queue_discard_max_entry.attr,
 499         &queue_discard_max_hw_entry.attr,
 500         &queue_discard_zeroes_data_entry.attr,
 501         &queue_write_same_max_entry.attr,
 502         &queue_nonrot_entry.attr,
 503         &queue_nomerges_entry.attr,
 504         &queue_rq_affinity_entry.attr,
 505         &queue_iostats_entry.attr,
 506         &queue_random_entry.attr,
 507         &queue_poll_entry.attr,
 508         NULL,
 509 };
 510
 511 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 512
 513 static ssize_t
 514 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 515 {
 516         struct queue_sysfs_entry *entry = to_queue(attr);
 517         struct request_queue *q =
 518                 container_of(kobj, struct request_queue, kobj);
 519         ssize_t res;
 520
 521         if (!entry->show)
 522                 return -EIO;
 523         mutex_lock(&q->sysfs_lock);
 524         if (blk_queue_dying(q)) {
 525                 mutex_unlock(&q->sysfs_lock);
 526                 return -ENOENT;
 527         }
 528         res = entry->show(q, page);
 529         mutex_unlock(&q->sysfs_lock);
 530         return res;
 531 }
 532
 533 static ssize_t
 534 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 535                     const char *page, size_t length)
 536 {
 537         struct queue_sysfs_entry *entry = to_queue(attr);
 538         struct request_queue *q;
 539         ssize_t res;
 540
 541         if (!entry->store)
 542                 return -EIO;
 543
 544         q = container_of(kobj, struct request_queue, kobj);
 545         mutex_lock(&q->sysfs_lock);
 546         if (blk_queue_dying(q)) {
 547                 mutex_unlock(&q->sysfs_lock);
 548                 return -ENOENT;
 549         }
 550         res = entry->store(q, page, length);
 551         mutex_unlock(&q->sysfs_lock);
 552         return res;
 553 }
 554
 555 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 556 {
 557         struct request_queue *q = container_of(rcu_head, struct request_queue,
 558                                                rcu_head);
 559         kmem_cache_free(blk_requestq_cachep, q);
 560 }
 561
 562 /**
 563  * blk_release_queue: - release a &struct request_queue when it is no longer needed
 564  * @kobj:    the kobj belonging to the request queue to be released
 565  *
 566  * Description:
 567  *     blk_release_queue is the pair to blk_init_queue() or
 568  *     blk_queue_make_request().  It should be called when a request queue is
 569  *     being released; typically when a block device is being de-registered.
 570  *     Currently, its primary task it to free all the &struct request
 571  *     structures that were allocated to the queue and the queue itself.
 572  *
 573  * Note:
 574  *     The low level driver must have finished any outstanding requests first
 575  *     via blk_cleanup_queue().
 576  **/
 577 static void blk_release_queue(struct kobject *kobj)
 578 {
 579         struct request_queue *q =
 580                 container_of(kobj, struct request_queue, kobj);
 581
 582         bdi_put(q->backing_dev_info);
 583         blkcg_exit_queue(q);
 584
 585         if (q->elevator) {
 586                 spin_lock_irq(q->queue_lock);
 587                 ioc_clear_queue(q);
 588                 spin_unlock_irq(q->queue_lock);
 589                 elevator_exit(q->elevator);
 590         }
 591
 592         blk_exit_rl(&q->root_rl);
 593
 594         if (q->queue_tags)
 595                 __blk_queue_free_tags(q);
 596
 597         if (!q->mq_ops)
 598                 blk_free_flush_queue(q->fq);
 599         else
 600                 blk_mq_release(q);
 601
 602         blk_trace_shutdown(q);
 603
 604         if (q->bio_split)
 605                 bioset_free(q->bio_split);
 606
 607         ida_simple_remove(&blk_queue_ida, q->id);
 608         call_rcu(&q->rcu_head, blk_free_queue_rcu);
 609 }
 610
 611 static const struct sysfs_ops queue_sysfs_ops = {
 612         .show   = queue_attr_show,
 613         .store  = queue_attr_store,
 614 };
 615
 616 struct kobj_type blk_queue_ktype = {
 617         .sysfs_ops      = &queue_sysfs_ops,
 618         .default_attrs  = default_attrs,
 619         .release        = blk_release_queue,
 620 };
 621
 622 int blk_register_queue(struct gendisk *disk)
 623 {
 624         int ret;
 625         struct device *dev = disk_to_dev(disk);
 626         struct request_queue *q = disk->queue;
 627
 628         if (WARN_ON(!q))
 629                 return -ENXIO;
 630
 631         /*
 632          * SCSI probing may synchronously create and destroy a lot of
 633          * request_queues for non-existent devices.  Shutting down a fully
 634          * functional queue takes measureable wallclock time as RCU grace
 635          * periods are involved.  To avoid excessive latency in these
 636          * cases, a request_queue starts out in a degraded mode which is
 637          * faster to shut down and is made fully functional here as
 638          * request_queues for non-existent devices never get registered.
 639          */
 640         if (!blk_queue_init_done(q)) {
 641                 queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
 642                 percpu_ref_switch_to_percpu(&q->q_usage_counter);
 643                 blk_queue_bypass_end(q);
 644         }
 645
 646         ret = blk_trace_init_sysfs(dev);
 647         if (ret)
 648                 return ret;
 649
 650         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 651         if (ret < 0) {
 652                 blk_trace_remove_sysfs(dev);
 653                 return ret;
 654         }
 655
 656         kobject_uevent(&q->kobj, KOBJ_ADD);
 657
 658         if (q->mq_ops)
 659                 blk_mq_register_disk(disk);
 660
 661         if (!q->request_fn)
 662                 return 0;
 663
 664         ret = elv_register_queue(q);
 665         if (ret) {
 666                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 667                 kobject_del(&q->kobj);
 668                 blk_trace_remove_sysfs(dev);
 669                 kobject_put(&dev->kobj);
 670                 return ret;
 671         }
 672
 673         return 0;
 674 }
 675
 676 void blk_unregister_queue(struct gendisk *disk)
 677 {
 678         struct request_queue *q = disk->queue;
 679
 680         if (WARN_ON(!q))
 681                 return;
 682
 683         if (q->mq_ops)
 684                 blk_mq_unregister_disk(disk);
 685
 686         if (q->request_fn)
 687                 elv_unregister_queue(q);
 688
 689         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 690         kobject_del(&q->kobj);
 691         blk_trace_remove_sysfs(disk_to_dev(disk));
 692         kobject_put(&disk_to_dev(disk)->kobj);
 693 }