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 #include "blk-wbt.h"
  17
  18 struct queue_sysfs_entry {
  19         struct attribute attr;
  20         ssize_t (*show)(struct request_queue *, char *);
  21         ssize_t (*store)(struct request_queue *, const char *, size_t);
  22 };
  23
  24 static ssize_t
  25 queue_var_show(unsigned long var, char *page)
  26 {
  27         return sprintf(page, "%lu\n", var);
  28 }
  29
  30 static ssize_t
  31 queue_var_store(unsigned long *var, const char *page, size_t count)
  32 {
  33         int err;
  34         unsigned long v;
  35
  36         err = kstrtoul(page, 10, &v);
  37         if (err || v > UINT_MAX)
  38                 return -EINVAL;
  39
  40         *var = v;
  41
  42         return count;
  43 }
  44
  45 static ssize_t queue_var_store64(s64 *var, const char *page)
  46 {
  47         int err;
  48         s64 v;
  49
  50         err = kstrtos64(page, 10, &v);
  51         if (err < 0)
  52                 return err;
  53
  54         *var = v;
  55         return 0;
  56 }
  57
  58 static ssize_t queue_requests_show(struct request_queue *q, char *page)
  59 {
  60         return queue_var_show(q->nr_requests, (page));
  61 }
  62
  63 static ssize_t
  64 queue_requests_store(struct request_queue *q, const char *page, size_t count)
  65 {
  66         unsigned long nr;
  67         int ret, err;
  68
  69         if (!q->request_fn && !q->mq_ops)
  70                 return -EINVAL;
  71
  72         ret = queue_var_store(&nr, page, count);
  73         if (ret < 0)
  74                 return ret;
  75
  76         if (nr < BLKDEV_MIN_RQ)
  77                 nr = BLKDEV_MIN_RQ;
  78
  79         if (q->request_fn)
  80                 err = blk_update_nr_requests(q, nr);
  81         else
  82                 err = blk_mq_update_nr_requests(q, nr);
  83
  84         if (err)
  85                 return err;
  86
  87         return ret;
  88 }
  89
  90 static ssize_t queue_ra_show(struct request_queue *q, char *page)
  91 {
  92         unsigned long ra_kb = q->backing_dev_info.ra_pages <<
  93                                         (PAGE_SHIFT - 10);
  94
  95         return queue_var_show(ra_kb, (page));
  96 }
  97
  98 static ssize_t
  99 queue_ra_store(struct request_queue *q, const char *page, size_t count)
 100 {
 101         unsigned long ra_kb;
 102         ssize_t ret = queue_var_store(&ra_kb, page, count);
 103
 104         if (ret < 0)
 105                 return ret;
 106
 107         q->backing_dev_info.ra_pages = ra_kb >> (PAGE_SHIFT - 10);
 108
 109         return ret;
 110 }
 111
 112 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
 113 {
 114         int max_sectors_kb = queue_max_sectors(q) >> 1;
 115
 116         return queue_var_show(max_sectors_kb, (page));
 117 }
 118
 119 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
 120 {
 121         return queue_var_show(queue_max_segments(q), (page));
 122 }
 123
 124 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
 125 {
 126         return queue_var_show(q->limits.max_integrity_segments, (page));
 127 }
 128
 129 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 130 {
 131         if (blk_queue_cluster(q))
 132                 return queue_var_show(queue_max_segment_size(q), (page));
 133
 134         return queue_var_show(PAGE_SIZE, (page));
 135 }
 136
 137 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 138 {
 139         return queue_var_show(queue_logical_block_size(q), page);
 140 }
 141
 142 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 143 {
 144         return queue_var_show(queue_physical_block_size(q), page);
 145 }
 146
 147 static ssize_t queue_chunk_sectors_show(struct request_queue *q, char *page)
 148 {
 149         return queue_var_show(q->limits.chunk_sectors, page);
 150 }
 151
 152 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 153 {
 154         return queue_var_show(queue_io_min(q), page);
 155 }
 156
 157 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 158 {
 159         return queue_var_show(queue_io_opt(q), page);
 160 }
 161
 162 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 163 {
 164         return queue_var_show(q->limits.discard_granularity, page);
 165 }
 166
 167 static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
 168 {
 169
 170         return sprintf(page, "%llu\n",
 171                 (unsigned long long)q->limits.max_hw_discard_sectors << 9);
 172 }
 173
 174 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 175 {
 176         return sprintf(page, "%llu\n",
 177                        (unsigned long long)q->limits.max_discard_sectors << 9);
 178 }
 179
 180 static ssize_t queue_discard_max_store(struct request_queue *q,
 181                                        const char *page, size_t count)
 182 {
 183         unsigned long max_discard;
 184         ssize_t ret = queue_var_store(&max_discard, page, count);
 185
 186         if (ret < 0)
 187                 return ret;
 188
 189         if (max_discard & (q->limits.discard_granularity - 1))
 190                 return -EINVAL;
 191
 192         max_discard >>= 9;
 193         if (max_discard > UINT_MAX)
 194                 return -EINVAL;
 195
 196         if (max_discard > q->limits.max_hw_discard_sectors)
 197                 max_discard = q->limits.max_hw_discard_sectors;
 198
 199         q->limits.max_discard_sectors = max_discard;
 200         return ret;
 201 }
 202
 203 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 204 {
 205         return queue_var_show(queue_discard_zeroes_data(q), page);
 206 }
 207
 208 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
 209 {
 210         return sprintf(page, "%llu\n",
 211                 (unsigned long long)q->limits.max_write_same_sectors << 9);
 212 }
 213
 214 static ssize_t queue_write_zeroes_max_show(struct request_queue *q, char *page)
 215 {
 216         return sprintf(page, "%llu\n",
 217                 (unsigned long long)q->limits.max_write_zeroes_sectors << 9);
 218 }
 219
 220 static ssize_t
 221 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 222 {
 223         unsigned long max_sectors_kb,
 224                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 225                         page_kb = 1 << (PAGE_SHIFT - 10);
 226         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 227
 228         if (ret < 0)
 229                 return ret;
 230
 231         max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, (unsigned long)
 232                                          q->limits.max_dev_sectors >> 1);
 233
 234         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 235                 return -EINVAL;
 236
 237         spin_lock_irq(q->queue_lock);
 238         q->limits.max_sectors = max_sectors_kb << 1;
 239         spin_unlock_irq(q->queue_lock);
 240
 241         return ret;
 242 }
 243
 244 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 245 {
 246         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 247
 248         return queue_var_show(max_hw_sectors_kb, (page));
 249 }
 250
 251 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 252 static ssize_t                                                          \
 253 queue_show_##name(struct request_queue *q, char *page)                  \
 254 {                                                                       \
 255         int bit;                                                        \
 256         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 257         return queue_var_show(neg ? !bit : bit, page);                  \
 258 }                                                                       \
 259 static ssize_t                                                          \
 260 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
 261 {                                                                       \
 262         unsigned long val;                                              \
 263         ssize_t ret;                                                    \
 264         ret = queue_var_store(&val, page, count);                       \
 265         if (ret < 0)                                                    \
 266                  return ret;                                            \
 267         if (neg)                                                        \
 268                 val = !val;                                             \
 269                                                                         \
 270         spin_lock_irq(q->queue_lock);                                   \
 271         if (val)                                                        \
 272                 queue_flag_set(QUEUE_FLAG_##flag, q);                   \
 273         else                                                            \
 274                 queue_flag_clear(QUEUE_FLAG_##flag, q);                 \
 275         spin_unlock_irq(q->queue_lock);                                 \
 276         return ret;                                                     \
 277 }
 278
 279 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 280 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 281 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 282 #undef QUEUE_SYSFS_BIT_FNS
 283
 284 static ssize_t queue_zoned_show(struct request_queue *q, char *page)
 285 {
 286         switch (blk_queue_zoned_model(q)) {
 287         case BLK_ZONED_HA:
 288                 return sprintf(page, "host-aware\n");
 289         case BLK_ZONED_HM:
 290                 return sprintf(page, "host-managed\n");
 291         default:
 292                 return sprintf(page, "none\n");
 293         }
 294 }
 295
 296 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 297 {
 298         return queue_var_show((blk_queue_nomerges(q) << 1) |
 299                                blk_queue_noxmerges(q), page);
 300 }
 301
 302 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 303                                     size_t count)
 304 {
 305         unsigned long nm;
 306         ssize_t ret = queue_var_store(&nm, page, count);
 307
 308         if (ret < 0)
 309                 return ret;
 310
 311         spin_lock_irq(q->queue_lock);
 312         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 313         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 314         if (nm == 2)
 315                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 316         else if (nm)
 317                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 318         spin_unlock_irq(q->queue_lock);
 319
 320         return ret;
 321 }
 322
 323 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 324 {
 325         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 326         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 327
 328         return queue_var_show(set << force, page);
 329 }
 330
 331 static ssize_t
 332 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 333 {
 334         ssize_t ret = -EINVAL;
 335 #ifdef CONFIG_SMP
 336         unsigned long val;
 337
 338         ret = queue_var_store(&val, page, count);
 339         if (ret < 0)
 340                 return ret;
 341
 342         spin_lock_irq(q->queue_lock);
 343         if (val == 2) {
 344                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 345                 queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 346         } else if (val == 1) {
 347                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 348                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 349         } else if (val == 0) {
 350                 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 351                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 352         }
 353         spin_unlock_irq(q->queue_lock);
 354 #endif
 355         return ret;
 356 }
 357
 358 static ssize_t queue_poll_delay_show(struct request_queue *q, char *page)
 359 {
 360         int val;
 361
 362         if (q->poll_nsec == -1)
 363                 val = -1;
 364         else
 365                 val = q->poll_nsec / 1000;
 366
 367         return sprintf(page, "%d\n", val);
 368 }
 369
 370 static ssize_t queue_poll_delay_store(struct request_queue *q, const char *page,
 371                                 size_t count)
 372 {
 373         int err, val;
 374
 375         if (!q->mq_ops || !q->mq_ops->poll)
 376                 return -EINVAL;
 377
 378         err = kstrtoint(page, 10, &val);
 379         if (err < 0)
 380                 return err;
 381
 382         if (val == -1)
 383                 q->poll_nsec = -1;
 384         else
 385                 q->poll_nsec = val * 1000;
 386
 387         return count;
 388 }
 389
 390 static ssize_t queue_poll_show(struct request_queue *q, char *page)
 391 {
 392         return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
 393 }
 394
 395 static ssize_t queue_poll_store(struct request_queue *q, const char *page,
 396                                 size_t count)
 397 {
 398         unsigned long poll_on;
 399         ssize_t ret;
 400
 401         if (!q->mq_ops || !q->mq_ops->poll)
 402                 return -EINVAL;
 403
 404         ret = queue_var_store(&poll_on, page, count);
 405         if (ret < 0)
 406                 return ret;
 407
 408         spin_lock_irq(q->queue_lock);
 409         if (poll_on)
 410                 queue_flag_set(QUEUE_FLAG_POLL, q);
 411         else
 412                 queue_flag_clear(QUEUE_FLAG_POLL, q);
 413         spin_unlock_irq(q->queue_lock);
 414
 415         return ret;
 416 }
 417
 418 static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
 419 {
 420         if (!q->rq_wb)
 421                 return -EINVAL;
 422
 423         return sprintf(page, "%llu\n", div_u64(q->rq_wb->min_lat_nsec, 1000));
 424 }
 425
 426 static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
 427                                   size_t count)
 428 {
 429         struct rq_wb *rwb;
 430         ssize_t ret;
 431         s64 val;
 432
 433         ret = queue_var_store64(&val, page);
 434         if (ret < 0)
 435                 return ret;
 436         if (val < -1)
 437                 return -EINVAL;
 438
 439         rwb = q->rq_wb;
 440         if (!rwb) {
 441                 ret = wbt_init(q);
 442                 if (ret)
 443                         return ret;
 444
 445                 rwb = q->rq_wb;
 446                 if (!rwb)
 447                         return -EINVAL;
 448         }
 449
 450         if (val == -1)
 451                 rwb->min_lat_nsec = wbt_default_latency_nsec(q);
 452         else if (val >= 0)
 453                 rwb->min_lat_nsec = val * 1000ULL;
 454
 455         if (rwb->enable_state == WBT_STATE_ON_DEFAULT)
 456                 rwb->enable_state = WBT_STATE_ON_MANUAL;
 457
 458         wbt_update_limits(rwb);
 459         return count;
 460 }
 461
 462 static ssize_t queue_wc_show(struct request_queue *q, char *page)
 463 {
 464         if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
 465                 return sprintf(page, "write back\n");
 466
 467         return sprintf(page, "write through\n");
 468 }
 469
 470 static ssize_t queue_wc_store(struct request_queue *q, const char *page,
 471                               size_t count)
 472 {
 473         int set = -1;
 474
 475         if (!strncmp(page, "write back", 10))
 476                 set = 1;
 477         else if (!strncmp(page, "write through", 13) ||
 478                  !strncmp(page, "none", 4))
 479                 set = 0;
 480
 481         if (set == -1)
 482                 return -EINVAL;
 483
 484         spin_lock_irq(q->queue_lock);
 485         if (set)
 486                 queue_flag_set(QUEUE_FLAG_WC, q);
 487         else
 488                 queue_flag_clear(QUEUE_FLAG_WC, q);
 489         spin_unlock_irq(q->queue_lock);
 490
 491         return count;
 492 }
 493
 494 static ssize_t queue_dax_show(struct request_queue *q, char *page)
 495 {
 496         return queue_var_show(blk_queue_dax(q), page);
 497 }
 498
 499 static ssize_t print_stat(char *page, struct blk_rq_stat *stat, const char *pre)
 500 {
 501         return sprintf(page, "%s samples=%llu, mean=%lld, min=%lld, max=%lld\n",
 502                         pre, (long long) stat->nr_samples,
 503                         (long long) stat->mean, (long long) stat->min,
 504                         (long long) stat->max);
 505 }
 506
 507 static ssize_t queue_stats_show(struct request_queue *q, char *page)
 508 {
 509         struct blk_rq_stat stat[2];
 510         ssize_t ret;
 511
 512         blk_queue_stat_get(q, stat);
 513
 514         ret = print_stat(page, &stat[BLK_STAT_READ], "read :");
 515         ret += print_stat(page + ret, &stat[BLK_STAT_WRITE], "write:");
 516         return ret;
 517 }
 518
 519 static struct queue_sysfs_entry queue_requests_entry = {
 520         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 521         .show = queue_requests_show,
 522         .store = queue_requests_store,
 523 };
 524
 525 static struct queue_sysfs_entry queue_ra_entry = {
 526         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 527         .show = queue_ra_show,
 528         .store = queue_ra_store,
 529 };
 530
 531 static struct queue_sysfs_entry queue_max_sectors_entry = {
 532         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 533         .show = queue_max_sectors_show,
 534         .store = queue_max_sectors_store,
 535 };
 536
 537 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 538         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 539         .show = queue_max_hw_sectors_show,
 540 };
 541
 542 static struct queue_sysfs_entry queue_max_segments_entry = {
 543         .attr = {.name = "max_segments", .mode = S_IRUGO },
 544         .show = queue_max_segments_show,
 545 };
 546
 547 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
 548         .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
 549         .show = queue_max_integrity_segments_show,
 550 };
 551
 552 static struct queue_sysfs_entry queue_max_segment_size_entry = {
 553         .attr = {.name = "max_segment_size", .mode = S_IRUGO },
 554         .show = queue_max_segment_size_show,
 555 };
 556
 557 static struct queue_sysfs_entry queue_iosched_entry = {
 558         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 559         .show = elv_iosched_show,
 560         .store = elv_iosched_store,
 561 };
 562
 563 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 564         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 565         .show = queue_logical_block_size_show,
 566 };
 567
 568 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 569         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 570         .show = queue_logical_block_size_show,
 571 };
 572
 573 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 574         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 575         .show = queue_physical_block_size_show,
 576 };
 577
 578 static struct queue_sysfs_entry queue_chunk_sectors_entry = {
 579         .attr = {.name = "chunk_sectors", .mode = S_IRUGO },
 580         .show = queue_chunk_sectors_show,
 581 };
 582
 583 static struct queue_sysfs_entry queue_io_min_entry = {
 584         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 585         .show = queue_io_min_show,
 586 };
 587
 588 static struct queue_sysfs_entry queue_io_opt_entry = {
 589         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 590         .show = queue_io_opt_show,
 591 };
 592
 593 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 594         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
 595         .show = queue_discard_granularity_show,
 596 };
 597
 598 static struct queue_sysfs_entry queue_discard_max_hw_entry = {
 599         .attr = {.name = "discard_max_hw_bytes", .mode = S_IRUGO },
 600         .show = queue_discard_max_hw_show,
 601 };
 602
 603 static struct queue_sysfs_entry queue_discard_max_entry = {
 604         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO | S_IWUSR },
 605         .show = queue_discard_max_show,
 606         .store = queue_discard_max_store,
 607 };
 608
 609 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 610         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
 611         .show = queue_discard_zeroes_data_show,
 612 };
 613
 614 static struct queue_sysfs_entry queue_write_same_max_entry = {
 615         .attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
 616         .show = queue_write_same_max_show,
 617 };
 618
 619 static struct queue_sysfs_entry queue_write_zeroes_max_entry = {
 620         .attr = {.name = "write_zeroes_max_bytes", .mode = S_IRUGO },
 621         .show = queue_write_zeroes_max_show,
 622 };
 623
 624 static struct queue_sysfs_entry queue_nonrot_entry = {
 625         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 626         .show = queue_show_nonrot,
 627         .store = queue_store_nonrot,
 628 };
 629
 630 static struct queue_sysfs_entry queue_zoned_entry = {
 631         .attr = {.name = "zoned", .mode = S_IRUGO },
 632         .show = queue_zoned_show,
 633 };
 634
 635 static struct queue_sysfs_entry queue_nomerges_entry = {
 636         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 637         .show = queue_nomerges_show,
 638         .store = queue_nomerges_store,
 639 };
 640
 641 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 642         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 643         .show = queue_rq_affinity_show,
 644         .store = queue_rq_affinity_store,
 645 };
 646
 647 static struct queue_sysfs_entry queue_iostats_entry = {
 648         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 649         .show = queue_show_iostats,
 650         .store = queue_store_iostats,
 651 };
 652
 653 static struct queue_sysfs_entry queue_random_entry = {
 654         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
 655         .show = queue_show_random,
 656         .store = queue_store_random,
 657 };
 658
 659 static struct queue_sysfs_entry queue_poll_entry = {
 660         .attr = {.name = "io_poll", .mode = S_IRUGO | S_IWUSR },
 661         .show = queue_poll_show,
 662         .store = queue_poll_store,
 663 };
 664
 665 static struct queue_sysfs_entry queue_poll_delay_entry = {
 666         .attr = {.name = "io_poll_delay", .mode = S_IRUGO | S_IWUSR },
 667         .show = queue_poll_delay_show,
 668         .store = queue_poll_delay_store,
 669 };
 670
 671 static struct queue_sysfs_entry queue_wc_entry = {
 672         .attr = {.name = "write_cache", .mode = S_IRUGO | S_IWUSR },
 673         .show = queue_wc_show,
 674         .store = queue_wc_store,
 675 };
 676
 677 static struct queue_sysfs_entry queue_dax_entry = {
 678         .attr = {.name = "dax", .mode = S_IRUGO },
 679         .show = queue_dax_show,
 680 };
 681
 682 static struct queue_sysfs_entry queue_stats_entry = {
 683         .attr = {.name = "stats", .mode = S_IRUGO },
 684         .show = queue_stats_show,
 685 };
 686
 687 static struct queue_sysfs_entry queue_wb_lat_entry = {
 688         .attr = {.name = "wbt_lat_usec", .mode = S_IRUGO | S_IWUSR },
 689         .show = queue_wb_lat_show,
 690         .store = queue_wb_lat_store,
 691 };
 692
 693 static struct attribute *default_attrs[] = {
 694         &queue_requests_entry.attr,
 695         &queue_ra_entry.attr,
 696         &queue_max_hw_sectors_entry.attr,
 697         &queue_max_sectors_entry.attr,
 698         &queue_max_segments_entry.attr,
 699         &queue_max_integrity_segments_entry.attr,
 700         &queue_max_segment_size_entry.attr,
 701         &queue_iosched_entry.attr,
 702         &queue_hw_sector_size_entry.attr,
 703         &queue_logical_block_size_entry.attr,
 704         &queue_physical_block_size_entry.attr,
 705         &queue_chunk_sectors_entry.attr,
 706         &queue_io_min_entry.attr,
 707         &queue_io_opt_entry.attr,
 708         &queue_discard_granularity_entry.attr,
 709         &queue_discard_max_entry.attr,
 710         &queue_discard_max_hw_entry.attr,
 711         &queue_discard_zeroes_data_entry.attr,
 712         &queue_write_same_max_entry.attr,
 713         &queue_write_zeroes_max_entry.attr,
 714         &queue_nonrot_entry.attr,
 715         &queue_zoned_entry.attr,
 716         &queue_nomerges_entry.attr,
 717         &queue_rq_affinity_entry.attr,
 718         &queue_iostats_entry.attr,
 719         &queue_random_entry.attr,
 720         &queue_poll_entry.attr,
 721         &queue_wc_entry.attr,
 722         &queue_dax_entry.attr,
 723         &queue_stats_entry.attr,
 724         &queue_wb_lat_entry.attr,
 725         &queue_poll_delay_entry.attr,
 726         NULL,
 727 };
 728
 729 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 730
 731 static ssize_t
 732 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 733 {
 734         struct queue_sysfs_entry *entry = to_queue(attr);
 735         struct request_queue *q =
 736                 container_of(kobj, struct request_queue, kobj);
 737         ssize_t res;
 738
 739         if (!entry->show)
 740                 return -EIO;
 741         mutex_lock(&q->sysfs_lock);
 742         if (blk_queue_dying(q)) {
 743                 mutex_unlock(&q->sysfs_lock);
 744                 return -ENOENT;
 745         }
 746         res = entry->show(q, page);
 747         mutex_unlock(&q->sysfs_lock);
 748         return res;
 749 }
 750
 751 static ssize_t
 752 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 753                     const char *page, size_t length)
 754 {
 755         struct queue_sysfs_entry *entry = to_queue(attr);
 756         struct request_queue *q;
 757         ssize_t res;
 758
 759         if (!entry->store)
 760                 return -EIO;
 761
 762         q = container_of(kobj, struct request_queue, kobj);
 763         mutex_lock(&q->sysfs_lock);
 764         if (blk_queue_dying(q)) {
 765                 mutex_unlock(&q->sysfs_lock);
 766                 return -ENOENT;
 767         }
 768         res = entry->store(q, page, length);
 769         mutex_unlock(&q->sysfs_lock);
 770         return res;
 771 }
 772
 773 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 774 {
 775         struct request_queue *q = container_of(rcu_head, struct request_queue,
 776                                                rcu_head);
 777         kmem_cache_free(blk_requestq_cachep, q);
 778 }
 779
 780 /**
 781  * blk_release_queue: - release a &struct request_queue when it is no longer needed
 782  * @kobj:    the kobj belonging to the request queue to be released
 783  *
 784  * Description:
 785  *     blk_release_queue is the pair to blk_init_queue() or
 786  *     blk_queue_make_request().  It should be called when a request queue is
 787  *     being released; typically when a block device is being de-registered.
 788  *     Currently, its primary task it to free all the &struct request
 789  *     structures that were allocated to the queue and the queue itself.
 790  *
 791  * Note:
 792  *     The low level driver must have finished any outstanding requests first
 793  *     via blk_cleanup_queue().
 794  **/
 795 static void blk_release_queue(struct kobject *kobj)
 796 {
 797         struct request_queue *q =
 798                 container_of(kobj, struct request_queue, kobj);
 799
 800         wbt_exit(q);
 801         bdi_exit(&q->backing_dev_info);
 802         blkcg_exit_queue(q);
 803
 804         if (q->elevator) {
 805                 spin_lock_irq(q->queue_lock);
 806                 ioc_clear_queue(q);
 807                 spin_unlock_irq(q->queue_lock);
 808                 elevator_exit(q->elevator);
 809         }
 810
 811         blk_exit_rl(&q->root_rl);
 812
 813         if (q->queue_tags)
 814                 __blk_queue_free_tags(q);
 815
 816         if (!q->mq_ops)
 817                 blk_free_flush_queue(q->fq);
 818         else
 819                 blk_mq_release(q);
 820
 821         blk_trace_shutdown(q);
 822
 823         if (q->bio_split)
 824                 bioset_free(q->bio_split);
 825
 826         ida_simple_remove(&blk_queue_ida, q->id);
 827         call_rcu(&q->rcu_head, blk_free_queue_rcu);
 828 }
 829
 830 static const struct sysfs_ops queue_sysfs_ops = {
 831         .show   = queue_attr_show,
 832         .store  = queue_attr_store,
 833 };
 834
 835 struct kobj_type blk_queue_ktype = {
 836         .sysfs_ops      = &queue_sysfs_ops,
 837         .default_attrs  = default_attrs,
 838         .release        = blk_release_queue,
 839 };
 840
 841 static void blk_wb_init(struct request_queue *q)
 842 {
 843 #ifndef CONFIG_BLK_WBT_MQ
 844         if (q->mq_ops)
 845                 return;
 846 #endif
 847 #ifndef CONFIG_BLK_WBT_SQ
 848         if (q->request_fn)
 849                 return;
 850 #endif
 851
 852         /*
 853          * If this fails, we don't get throttling
 854          */
 855         wbt_init(q);
 856 }
 857
 858 int blk_register_queue(struct gendisk *disk)
 859 {
 860         int ret;
 861         struct device *dev = disk_to_dev(disk);
 862         struct request_queue *q = disk->queue;
 863
 864         if (WARN_ON(!q))
 865                 return -ENXIO;
 866
 867         /*
 868          * SCSI probing may synchronously create and destroy a lot of
 869          * request_queues for non-existent devices.  Shutting down a fully
 870          * functional queue takes measureable wallclock time as RCU grace
 871          * periods are involved.  To avoid excessive latency in these
 872          * cases, a request_queue starts out in a degraded mode which is
 873          * faster to shut down and is made fully functional here as
 874          * request_queues for non-existent devices never get registered.
 875          */
 876         if (!blk_queue_init_done(q)) {
 877                 queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
 878                 percpu_ref_switch_to_percpu(&q->q_usage_counter);
 879                 blk_queue_bypass_end(q);
 880         }
 881
 882         ret = blk_trace_init_sysfs(dev);
 883         if (ret)
 884                 return ret;
 885
 886         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 887         if (ret < 0) {
 888                 blk_trace_remove_sysfs(dev);
 889                 return ret;
 890         }
 891
 892         kobject_uevent(&q->kobj, KOBJ_ADD);
 893
 894         if (q->mq_ops)
 895                 blk_mq_register_dev(dev, q);
 896
 897         blk_wb_init(q);
 898
 899         if (!q->request_fn)
 900                 return 0;
 901
 902         ret = elv_register_queue(q);
 903         if (ret) {
 904                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 905                 kobject_del(&q->kobj);
 906                 blk_trace_remove_sysfs(dev);
 907                 kobject_put(&dev->kobj);
 908                 return ret;
 909         }
 910
 911         return 0;
 912 }
 913
 914 void blk_unregister_queue(struct gendisk *disk)
 915 {
 916         struct request_queue *q = disk->queue;
 917
 918         if (WARN_ON(!q))
 919                 return;
 920
 921         if (q->mq_ops)
 922                 blk_mq_unregister_dev(disk_to_dev(disk), q);
 923
 924         if (q->request_fn)
 925                 elv_unregister_queue(q);
 926
 927         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 928         kobject_del(&q->kobj);
 929         blk_trace_remove_sysfs(disk_to_dev(disk));
 930         kobject_put(&disk_to_dev(disk)->kobj);
 931 }