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         q->backing_dev_info.io_pages = max_sectors_kb >> (PAGE_SHIFT - 10);
 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 ssize_t queue_wc_show(struct request_queue *q, char *page)
 352 {
 353         if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
 354                 return sprintf(page, "write back\n");
 355
 356         return sprintf(page, "write through\n");
 357 }
 358
 359 static ssize_t queue_wc_store(struct request_queue *q, const char *page,
 360                               size_t count)
 361 {
 362         int set = -1;
 363
 364         if (!strncmp(page, "write back", 10))
 365                 set = 1;
 366         else if (!strncmp(page, "write through", 13) ||
 367                  !strncmp(page, "none", 4))
 368                 set = 0;
 369
 370         if (set == -1)
 371                 return -EINVAL;
 372
 373         spin_lock_irq(q->queue_lock);
 374         if (set)
 375                 queue_flag_set(QUEUE_FLAG_WC, q);
 376         else
 377                 queue_flag_clear(QUEUE_FLAG_WC, q);
 378         spin_unlock_irq(q->queue_lock);
 379
 380         return count;
 381 }
 382
 383 static ssize_t queue_dax_show(struct request_queue *q, char *page)
 384 {
 385         return queue_var_show(blk_queue_dax(q), page);
 386 }
 387
 388 static struct queue_sysfs_entry queue_requests_entry = {
 389         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 390         .show = queue_requests_show,
 391         .store = queue_requests_store,
 392 };
 393
 394 static struct queue_sysfs_entry queue_ra_entry = {
 395         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 396         .show = queue_ra_show,
 397         .store = queue_ra_store,
 398 };
 399
 400 static struct queue_sysfs_entry queue_max_sectors_entry = {
 401         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 402         .show = queue_max_sectors_show,
 403         .store = queue_max_sectors_store,
 404 };
 405
 406 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 407         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 408         .show = queue_max_hw_sectors_show,
 409 };
 410
 411 static struct queue_sysfs_entry queue_max_segments_entry = {
 412         .attr = {.name = "max_segments", .mode = S_IRUGO },
 413         .show = queue_max_segments_show,
 414 };
 415
 416 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
 417         .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
 418         .show = queue_max_integrity_segments_show,
 419 };
 420
 421 static struct queue_sysfs_entry queue_max_segment_size_entry = {
 422         .attr = {.name = "max_segment_size", .mode = S_IRUGO },
 423         .show = queue_max_segment_size_show,
 424 };
 425
 426 static struct queue_sysfs_entry queue_iosched_entry = {
 427         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 428         .show = elv_iosched_show,
 429         .store = elv_iosched_store,
 430 };
 431
 432 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 433         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 434         .show = queue_logical_block_size_show,
 435 };
 436
 437 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 438         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 439         .show = queue_logical_block_size_show,
 440 };
 441
 442 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 443         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 444         .show = queue_physical_block_size_show,
 445 };
 446
 447 static struct queue_sysfs_entry queue_io_min_entry = {
 448         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 449         .show = queue_io_min_show,
 450 };
 451
 452 static struct queue_sysfs_entry queue_io_opt_entry = {
 453         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 454         .show = queue_io_opt_show,
 455 };
 456
 457 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 458         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
 459         .show = queue_discard_granularity_show,
 460 };
 461
 462 static struct queue_sysfs_entry queue_discard_max_hw_entry = {
 463         .attr = {.name = "discard_max_hw_bytes", .mode = S_IRUGO },
 464         .show = queue_discard_max_hw_show,
 465 };
 466
 467 static struct queue_sysfs_entry queue_discard_max_entry = {
 468         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO | S_IWUSR },
 469         .show = queue_discard_max_show,
 470         .store = queue_discard_max_store,
 471 };
 472
 473 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 474         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
 475         .show = queue_discard_zeroes_data_show,
 476 };
 477
 478 static struct queue_sysfs_entry queue_write_same_max_entry = {
 479         .attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
 480         .show = queue_write_same_max_show,
 481 };
 482
 483 static struct queue_sysfs_entry queue_nonrot_entry = {
 484         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 485         .show = queue_show_nonrot,
 486         .store = queue_store_nonrot,
 487 };
 488
 489 static struct queue_sysfs_entry queue_nomerges_entry = {
 490         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 491         .show = queue_nomerges_show,
 492         .store = queue_nomerges_store,
 493 };
 494
 495 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 496         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 497         .show = queue_rq_affinity_show,
 498         .store = queue_rq_affinity_store,
 499 };
 500
 501 static struct queue_sysfs_entry queue_iostats_entry = {
 502         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 503         .show = queue_show_iostats,
 504         .store = queue_store_iostats,
 505 };
 506
 507 static struct queue_sysfs_entry queue_random_entry = {
 508         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
 509         .show = queue_show_random,
 510         .store = queue_store_random,
 511 };
 512
 513 static struct queue_sysfs_entry queue_poll_entry = {
 514         .attr = {.name = "io_poll", .mode = S_IRUGO | S_IWUSR },
 515         .show = queue_poll_show,
 516         .store = queue_poll_store,
 517 };
 518
 519 static struct queue_sysfs_entry queue_wc_entry = {
 520         .attr = {.name = "write_cache", .mode = S_IRUGO | S_IWUSR },
 521         .show = queue_wc_show,
 522         .store = queue_wc_store,
 523 };
 524
 525 static struct queue_sysfs_entry queue_dax_entry = {
 526         .attr = {.name = "dax", .mode = S_IRUGO },
 527         .show = queue_dax_show,
 528 };
 529
 530 static struct attribute *default_attrs[] = {
 531         &queue_requests_entry.attr,
 532         &queue_ra_entry.attr,
 533         &queue_max_hw_sectors_entry.attr,
 534         &queue_max_sectors_entry.attr,
 535         &queue_max_segments_entry.attr,
 536         &queue_max_integrity_segments_entry.attr,
 537         &queue_max_segment_size_entry.attr,
 538         &queue_iosched_entry.attr,
 539         &queue_hw_sector_size_entry.attr,
 540         &queue_logical_block_size_entry.attr,
 541         &queue_physical_block_size_entry.attr,
 542         &queue_io_min_entry.attr,
 543         &queue_io_opt_entry.attr,
 544         &queue_discard_granularity_entry.attr,
 545         &queue_discard_max_entry.attr,
 546         &queue_discard_max_hw_entry.attr,
 547         &queue_discard_zeroes_data_entry.attr,
 548         &queue_write_same_max_entry.attr,
 549         &queue_nonrot_entry.attr,
 550         &queue_nomerges_entry.attr,
 551         &queue_rq_affinity_entry.attr,
 552         &queue_iostats_entry.attr,
 553         &queue_random_entry.attr,
 554         &queue_poll_entry.attr,
 555         &queue_wc_entry.attr,
 556         &queue_dax_entry.attr,
 557         NULL,
 558 };
 559
 560 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 561
 562 static ssize_t
 563 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 564 {
 565         struct queue_sysfs_entry *entry = to_queue(attr);
 566         struct request_queue *q =
 567                 container_of(kobj, struct request_queue, kobj);
 568         ssize_t res;
 569
 570         if (!entry->show)
 571                 return -EIO;
 572         mutex_lock(&q->sysfs_lock);
 573         if (blk_queue_dying(q)) {
 574                 mutex_unlock(&q->sysfs_lock);
 575                 return -ENOENT;
 576         }
 577         res = entry->show(q, page);
 578         mutex_unlock(&q->sysfs_lock);
 579         return res;
 580 }
 581
 582 static ssize_t
 583 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 584                     const char *page, size_t length)
 585 {
 586         struct queue_sysfs_entry *entry = to_queue(attr);
 587         struct request_queue *q;
 588         ssize_t res;
 589
 590         if (!entry->store)
 591                 return -EIO;
 592
 593         q = container_of(kobj, struct request_queue, kobj);
 594         mutex_lock(&q->sysfs_lock);
 595         if (blk_queue_dying(q)) {
 596                 mutex_unlock(&q->sysfs_lock);
 597                 return -ENOENT;
 598         }
 599         res = entry->store(q, page, length);
 600         mutex_unlock(&q->sysfs_lock);
 601         return res;
 602 }
 603
 604 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 605 {
 606         struct request_queue *q = container_of(rcu_head, struct request_queue,
 607                                                rcu_head);
 608         kmem_cache_free(blk_requestq_cachep, q);
 609 }
 610
 611 /**
 612  * blk_release_queue: - release a &struct request_queue when it is no longer needed
 613  * @kobj:    the kobj belonging to the request queue to be released
 614  *
 615  * Description:
 616  *     blk_release_queue is the pair to blk_init_queue() or
 617  *     blk_queue_make_request().  It should be called when a request queue is
 618  *     being released; typically when a block device is being de-registered.
 619  *     Currently, its primary task it to free all the &struct request
 620  *     structures that were allocated to the queue and the queue itself.
 621  *
 622  * Note:
 623  *     The low level driver must have finished any outstanding requests first
 624  *     via blk_cleanup_queue().
 625  **/
 626 static void blk_release_queue(struct kobject *kobj)
 627 {
 628         struct request_queue *q =
 629                 container_of(kobj, struct request_queue, kobj);
 630
 631         bdi_exit(&q->backing_dev_info);
 632         blkcg_exit_queue(q);
 633
 634         if (q->elevator) {
 635                 spin_lock_irq(q->queue_lock);
 636                 ioc_clear_queue(q);
 637                 spin_unlock_irq(q->queue_lock);
 638                 elevator_exit(q->elevator);
 639         }
 640
 641         blk_exit_rl(&q->root_rl);
 642
 643         if (q->queue_tags)
 644                 __blk_queue_free_tags(q);
 645
 646         if (!q->mq_ops)
 647                 blk_free_flush_queue(q->fq);
 648         else
 649                 blk_mq_release(q);
 650
 651         blk_trace_shutdown(q);
 652
 653         if (q->bio_split)
 654                 bioset_free(q->bio_split);
 655
 656         ida_simple_remove(&blk_queue_ida, q->id);
 657         call_rcu(&q->rcu_head, blk_free_queue_rcu);
 658 }
 659
 660 static const struct sysfs_ops queue_sysfs_ops = {
 661         .show   = queue_attr_show,
 662         .store  = queue_attr_store,
 663 };
 664
 665 struct kobj_type blk_queue_ktype = {
 666         .sysfs_ops      = &queue_sysfs_ops,
 667         .default_attrs  = default_attrs,
 668         .release        = blk_release_queue,
 669 };
 670
 671 int blk_register_queue(struct gendisk *disk)
 672 {
 673         int ret;
 674         struct device *dev = disk_to_dev(disk);
 675         struct request_queue *q = disk->queue;
 676
 677         if (WARN_ON(!q))
 678                 return -ENXIO;
 679
 680         /*
 681          * SCSI probing may synchronously create and destroy a lot of
 682          * request_queues for non-existent devices.  Shutting down a fully
 683          * functional queue takes measureable wallclock time as RCU grace
 684          * periods are involved.  To avoid excessive latency in these
 685          * cases, a request_queue starts out in a degraded mode which is
 686          * faster to shut down and is made fully functional here as
 687          * request_queues for non-existent devices never get registered.
 688          */
 689         if (!blk_queue_init_done(q)) {
 690                 queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
 691                 percpu_ref_switch_to_percpu(&q->q_usage_counter);
 692                 blk_queue_bypass_end(q);
 693         }
 694
 695         ret = blk_trace_init_sysfs(dev);
 696         if (ret)
 697                 return ret;
 698
 699         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 700         if (ret < 0) {
 701                 blk_trace_remove_sysfs(dev);
 702                 return ret;
 703         }
 704
 705         kobject_uevent(&q->kobj, KOBJ_ADD);
 706
 707         if (q->mq_ops)
 708                 blk_mq_register_dev(dev, q);
 709
 710         if (!q->request_fn)
 711                 return 0;
 712
 713         ret = elv_register_queue(q);
 714         if (ret) {
 715                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 716                 kobject_del(&q->kobj);
 717                 blk_trace_remove_sysfs(dev);
 718                 kobject_put(&dev->kobj);
 719                 return ret;
 720         }
 721
 722         return 0;
 723 }
 724
 725 void blk_unregister_queue(struct gendisk *disk)
 726 {
 727         struct request_queue *q = disk->queue;
 728
 729         if (WARN_ON(!q))
 730                 return;
 731
 732         if (q->mq_ops)
 733                 blk_mq_unregister_dev(disk_to_dev(disk), q);
 734
 735         if (q->request_fn)
 736                 elv_unregister_queue(q);
 737
 738         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 739         kobject_del(&q->kobj);
 740         blk_trace_remove_sysfs(disk_to_dev(disk));
 741         kobject_put(&disk_to_dev(disk)->kobj);
 742 }