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