block/blk-sysfs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Functions related to sysfs handling
   4  */
   5 #include <linux/kernel.h>
   6 #include <linux/slab.h>
   7 #include <linux/module.h>
   8 #include <linux/bio.h>
   9 #include <linux/blkdev.h>
  10 #include <linux/backing-dev.h>
  11 #include <linux/blktrace_api.h>
  12 #include <linux/blk-mq.h>
  13 #include <linux/blk-cgroup.h>
  14 #include <linux/debugfs.h>
  15
  16 #include "blk.h"
  17 #include "blk-mq.h"
  18 #include "blk-mq-debugfs.h"
  19 #include "blk-mq-sched.h"
  20 #include "blk-wbt.h"
  21 #include "blk-throttle.h"
  22
  23 struct queue_sysfs_entry {
  24         struct attribute attr;
  25         ssize_t (*show)(struct request_queue *, char *);
  26         ssize_t (*store)(struct request_queue *, const char *, size_t);
  27 };
  28
  29 static ssize_t
  30 queue_var_show(unsigned long var, char *page)
  31 {
  32         return sprintf(page, "%lu\n", var);
  33 }
  34
  35 static ssize_t
  36 queue_var_store(unsigned long *var, const char *page, size_t count)
  37 {
  38         int err;
  39         unsigned long v;
  40
  41         err = kstrtoul(page, 10, &v);
  42         if (err || v > UINT_MAX)
  43                 return -EINVAL;
  44
  45         *var = v;
  46
  47         return count;
  48 }
  49
  50 static ssize_t queue_var_store64(s64 *var, const char *page)
  51 {
  52         int err;
  53         s64 v;
  54
  55         err = kstrtos64(page, 10, &v);
  56         if (err < 0)
  57                 return err;
  58
  59         *var = v;
  60         return 0;
  61 }
  62
  63 static ssize_t queue_requests_show(struct request_queue *q, char *page)
  64 {
  65         return queue_var_show(q->nr_requests, page);
  66 }
  67
  68 static ssize_t
  69 queue_requests_store(struct request_queue *q, const char *page, size_t count)
  70 {
  71         unsigned long nr;
  72         int ret, err;
  73
  74         if (!queue_is_mq(q))
  75                 return -EINVAL;
  76
  77         ret = queue_var_store(&nr, page, count);
  78         if (ret < 0)
  79                 return ret;
  80
  81         if (nr < BLKDEV_MIN_RQ)
  82                 nr = BLKDEV_MIN_RQ;
  83
  84         err = blk_mq_update_nr_requests(q, nr);
  85         if (err)
  86                 return err;
  87
  88         return ret;
  89 }
  90
  91 static ssize_t queue_ra_show(struct request_queue *q, char *page)
  92 {
  93         unsigned long ra_kb;
  94
  95         if (!q->disk)
  96                 return -EINVAL;
  97         ra_kb = q->disk->bdi->ra_pages << (PAGE_SHIFT - 10);
  98         return queue_var_show(ra_kb, page);
  99 }
 100
 101 static ssize_t
 102 queue_ra_store(struct request_queue *q, const char *page, size_t count)
 103 {
 104         unsigned long ra_kb;
 105         ssize_t ret;
 106
 107         if (!q->disk)
 108                 return -EINVAL;
 109         ret = queue_var_store(&ra_kb, page, count);
 110         if (ret < 0)
 111                 return ret;
 112         q->disk->bdi->ra_pages = ra_kb >> (PAGE_SHIFT - 10);
 113         return ret;
 114 }
 115
 116 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
 117 {
 118         int max_sectors_kb = queue_max_sectors(q) >> 1;
 119
 120         return queue_var_show(max_sectors_kb, page);
 121 }
 122
 123 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
 124 {
 125         return queue_var_show(queue_max_segments(q), page);
 126 }
 127
 128 static ssize_t queue_max_discard_segments_show(struct request_queue *q,
 129                 char *page)
 130 {
 131         return queue_var_show(queue_max_discard_segments(q), page);
 132 }
 133
 134 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
 135 {
 136         return queue_var_show(q->limits.max_integrity_segments, page);
 137 }
 138
 139 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 140 {
 141         return queue_var_show(queue_max_segment_size(q), page);
 142 }
 143
 144 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 145 {
 146         return queue_var_show(queue_logical_block_size(q), page);
 147 }
 148
 149 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 150 {
 151         return queue_var_show(queue_physical_block_size(q), page);
 152 }
 153
 154 static ssize_t queue_chunk_sectors_show(struct request_queue *q, char *page)
 155 {
 156         return queue_var_show(q->limits.chunk_sectors, page);
 157 }
 158
 159 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 160 {
 161         return queue_var_show(queue_io_min(q), page);
 162 }
 163
 164 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 165 {
 166         return queue_var_show(queue_io_opt(q), page);
 167 }
 168
 169 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 170 {
 171         return queue_var_show(q->limits.discard_granularity, page);
 172 }
 173
 174 static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
 175 {
 176
 177         return sprintf(page, "%llu\n",
 178                 (unsigned long long)q->limits.max_hw_discard_sectors << 9);
 179 }
 180
 181 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 182 {
 183         return sprintf(page, "%llu\n",
 184                        (unsigned long long)q->limits.max_discard_sectors << 9);
 185 }
 186
 187 static ssize_t queue_discard_max_store(struct request_queue *q,
 188                                        const char *page, size_t count)
 189 {
 190         unsigned long max_discard;
 191         ssize_t ret = queue_var_store(&max_discard, page, count);
 192
 193         if (ret < 0)
 194                 return ret;
 195
 196         if (max_discard & (q->limits.discard_granularity - 1))
 197                 return -EINVAL;
 198
 199         max_discard >>= 9;
 200         if (max_discard > UINT_MAX)
 201                 return -EINVAL;
 202
 203         if (max_discard > q->limits.max_hw_discard_sectors)
 204                 max_discard = q->limits.max_hw_discard_sectors;
 205
 206         q->limits.max_discard_sectors = max_discard;
 207         return ret;
 208 }
 209
 210 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 211 {
 212         return queue_var_show(0, page);
 213 }
 214
 215 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
 216 {
 217         return sprintf(page, "%llu\n",
 218                 (unsigned long long)q->limits.max_write_same_sectors << 9);
 219 }
 220
 221 static ssize_t queue_write_zeroes_max_show(struct request_queue *q, char *page)
 222 {
 223         return sprintf(page, "%llu\n",
 224                 (unsigned long long)q->limits.max_write_zeroes_sectors << 9);
 225 }
 226
 227 static ssize_t queue_zone_write_granularity_show(struct request_queue *q,
 228                                                  char *page)
 229 {
 230         return queue_var_show(queue_zone_write_granularity(q), page);
 231 }
 232
 233 static ssize_t queue_zone_append_max_show(struct request_queue *q, char *page)
 234 {
 235         unsigned long long max_sectors = q->limits.max_zone_append_sectors;
 236
 237         return sprintf(page, "%llu\n", max_sectors << SECTOR_SHIFT);
 238 }
 239
 240 static ssize_t
 241 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 242 {
 243         unsigned long max_sectors_kb,
 244                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 245                         page_kb = 1 << (PAGE_SHIFT - 10);
 246         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 247
 248         if (ret < 0)
 249                 return ret;
 250
 251         max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, (unsigned long)
 252                                          q->limits.max_dev_sectors >> 1);
 253
 254         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 255                 return -EINVAL;
 256
 257         spin_lock_irq(&q->queue_lock);
 258         q->limits.max_sectors = max_sectors_kb << 1;
 259         if (q->disk)
 260                 q->disk->bdi->io_pages = max_sectors_kb >> (PAGE_SHIFT - 10);
 261         spin_unlock_irq(&q->queue_lock);
 262
 263         return ret;
 264 }
 265
 266 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 267 {
 268         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 269
 270         return queue_var_show(max_hw_sectors_kb, page);
 271 }
 272
 273 static ssize_t queue_virt_boundary_mask_show(struct request_queue *q, char *page)
 274 {
 275         return queue_var_show(q->limits.virt_boundary_mask, page);
 276 }
 277
 278 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 279 static ssize_t                                                          \
 280 queue_##name##_show(struct request_queue *q, char *page)                \
 281 {                                                                       \
 282         int bit;                                                        \
 283         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 284         return queue_var_show(neg ? !bit : bit, page);                  \
 285 }                                                                       \
 286 static ssize_t                                                          \
 287 queue_##name##_store(struct request_queue *q, const char *page, size_t count) \
 288 {                                                                       \
 289         unsigned long val;                                              \
 290         ssize_t ret;                                                    \
 291         ret = queue_var_store(&val, page, count);                       \
 292         if (ret < 0)                                                    \
 293                  return ret;                                            \
 294         if (neg)                                                        \
 295                 val = !val;                                             \
 296                                                                         \
 297         if (val)                                                        \
 298                 blk_queue_flag_set(QUEUE_FLAG_##flag, q);               \
 299         else                                                            \
 300                 blk_queue_flag_clear(QUEUE_FLAG_##flag, q);             \
 301         return ret;                                                     \
 302 }
 303
 304 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 305 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 306 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 307 QUEUE_SYSFS_BIT_FNS(stable_writes, STABLE_WRITES, 0);
 308 #undef QUEUE_SYSFS_BIT_FNS
 309
 310 static ssize_t queue_zoned_show(struct request_queue *q, char *page)
 311 {
 312         switch (blk_queue_zoned_model(q)) {
 313         case BLK_ZONED_HA:
 314                 return sprintf(page, "host-aware\n");
 315         case BLK_ZONED_HM:
 316                 return sprintf(page, "host-managed\n");
 317         default:
 318                 return sprintf(page, "none\n");
 319         }
 320 }
 321
 322 static ssize_t queue_nr_zones_show(struct request_queue *q, char *page)
 323 {
 324         return queue_var_show(blk_queue_nr_zones(q), page);
 325 }
 326
 327 static ssize_t queue_max_open_zones_show(struct request_queue *q, char *page)
 328 {
 329         return queue_var_show(queue_max_open_zones(q), page);
 330 }
 331
 332 static ssize_t queue_max_active_zones_show(struct request_queue *q, char *page)
 333 {
 334         return queue_var_show(queue_max_active_zones(q), page);
 335 }
 336
 337 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 338 {
 339         return queue_var_show((blk_queue_nomerges(q) << 1) |
 340                                blk_queue_noxmerges(q), page);
 341 }
 342
 343 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 344                                     size_t count)
 345 {
 346         unsigned long nm;
 347         ssize_t ret = queue_var_store(&nm, page, count);
 348
 349         if (ret < 0)
 350                 return ret;
 351
 352         blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 353         blk_queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 354         if (nm == 2)
 355                 blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 356         else if (nm)
 357                 blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 358
 359         return ret;
 360 }
 361
 362 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 363 {
 364         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 365         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 366
 367         return queue_var_show(set << force, page);
 368 }
 369
 370 static ssize_t
 371 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 372 {
 373         ssize_t ret = -EINVAL;
 374 #ifdef CONFIG_SMP
 375         unsigned long val;
 376
 377         ret = queue_var_store(&val, page, count);
 378         if (ret < 0)
 379                 return ret;
 380
 381         if (val == 2) {
 382                 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 383                 blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 384         } else if (val == 1) {
 385                 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 386                 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 387         } else if (val == 0) {
 388                 blk_queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 389                 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 390         }
 391 #endif
 392         return ret;
 393 }
 394
 395 static ssize_t queue_poll_delay_show(struct request_queue *q, char *page)
 396 {
 397         int val;
 398
 399         if (q->poll_nsec == BLK_MQ_POLL_CLASSIC)
 400                 val = BLK_MQ_POLL_CLASSIC;
 401         else
 402                 val = q->poll_nsec / 1000;
 403
 404         return sprintf(page, "%d\n", val);
 405 }
 406
 407 static ssize_t queue_poll_delay_store(struct request_queue *q, const char *page,
 408                                 size_t count)
 409 {
 410         int err, val;
 411
 412         if (!q->mq_ops || !q->mq_ops->poll)
 413                 return -EINVAL;
 414
 415         err = kstrtoint(page, 10, &val);
 416         if (err < 0)
 417                 return err;
 418
 419         if (val == BLK_MQ_POLL_CLASSIC)
 420                 q->poll_nsec = BLK_MQ_POLL_CLASSIC;
 421         else if (val >= 0)
 422                 q->poll_nsec = val * 1000;
 423         else
 424                 return -EINVAL;
 425
 426         return count;
 427 }
 428
 429 static ssize_t queue_poll_show(struct request_queue *q, char *page)
 430 {
 431         return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
 432 }
 433
 434 static ssize_t queue_poll_store(struct request_queue *q, const char *page,
 435                                 size_t count)
 436 {
 437         if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
 438                 return -EINVAL;
 439         pr_info_ratelimited("writes to the poll attribute are ignored.\n");
 440         pr_info_ratelimited("please use driver specific parameters instead.\n");
 441         return count;
 442 }
 443
 444 static ssize_t queue_io_timeout_show(struct request_queue *q, char *page)
 445 {
 446         return sprintf(page, "%u\n", jiffies_to_msecs(q->rq_timeout));
 447 }
 448
 449 static ssize_t queue_io_timeout_store(struct request_queue *q, const char *page,
 450                                   size_t count)
 451 {
 452         unsigned int val;
 453         int err;
 454
 455         err = kstrtou32(page, 10, &val);
 456         if (err || val == 0)
 457                 return -EINVAL;
 458
 459         blk_queue_rq_timeout(q, msecs_to_jiffies(val));
 460
 461         return count;
 462 }
 463
 464 static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
 465 {
 466         if (!wbt_rq_qos(q))
 467                 return -EINVAL;
 468
 469         return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));
 470 }
 471
 472 static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
 473                                   size_t count)
 474 {
 475         struct rq_qos *rqos;
 476         ssize_t ret;
 477         s64 val;
 478
 479         ret = queue_var_store64(&val, page);
 480         if (ret < 0)
 481                 return ret;
 482         if (val < -1)
 483                 return -EINVAL;
 484
 485         rqos = wbt_rq_qos(q);
 486         if (!rqos) {
 487                 ret = wbt_init(q);
 488                 if (ret)
 489                         return ret;
 490         }
 491
 492         if (val == -1)
 493                 val = wbt_default_latency_nsec(q);
 494         else if (val >= 0)
 495                 val *= 1000ULL;
 496
 497         if (wbt_get_min_lat(q) == val)
 498                 return count;
 499
 500         /*
 501          * Ensure that the queue is idled, in case the latency update
 502          * ends up either enabling or disabling wbt completely. We can't
 503          * have IO inflight if that happens.
 504          */
 505         blk_mq_freeze_queue(q);
 506         blk_mq_quiesce_queue(q);
 507
 508         wbt_set_min_lat(q, val);
 509
 510         blk_mq_unquiesce_queue(q);
 511         blk_mq_unfreeze_queue(q);
 512
 513         return count;
 514 }
 515
 516 static ssize_t queue_wc_show(struct request_queue *q, char *page)
 517 {
 518         if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
 519                 return sprintf(page, "write back\n");
 520
 521         return sprintf(page, "write through\n");
 522 }
 523
 524 static ssize_t queue_wc_store(struct request_queue *q, const char *page,
 525                               size_t count)
 526 {
 527         int set = -1;
 528
 529         if (!strncmp(page, "write back", 10))
 530                 set = 1;
 531         else if (!strncmp(page, "write through", 13) ||
 532                  !strncmp(page, "none", 4))
 533                 set = 0;
 534
 535         if (set == -1)
 536                 return -EINVAL;
 537
 538         if (set)
 539                 blk_queue_flag_set(QUEUE_FLAG_WC, q);
 540         else
 541                 blk_queue_flag_clear(QUEUE_FLAG_WC, q);
 542
 543         return count;
 544 }
 545
 546 static ssize_t queue_fua_show(struct request_queue *q, char *page)
 547 {
 548         return sprintf(page, "%u\n", test_bit(QUEUE_FLAG_FUA, &q->queue_flags));
 549 }
 550
 551 static ssize_t queue_dax_show(struct request_queue *q, char *page)
 552 {
 553         return queue_var_show(blk_queue_dax(q), page);
 554 }
 555
 556 #define QUEUE_RO_ENTRY(_prefix, _name)                  \
 557 static struct queue_sysfs_entry _prefix##_entry = {     \
 558         .attr   = { .name = _name, .mode = 0444 },      \
 559         .show   = _prefix##_show,                       \
 560 };
 561
 562 #define QUEUE_RW_ENTRY(_prefix, _name)                  \
 563 static struct queue_sysfs_entry _prefix##_entry = {     \
 564         .attr   = { .name = _name, .mode = 0644 },      \
 565         .show   = _prefix##_show,                       \
 566         .store  = _prefix##_store,                      \
 567 };
 568
 569 QUEUE_RW_ENTRY(queue_requests, "nr_requests");
 570 QUEUE_RW_ENTRY(queue_ra, "read_ahead_kb");
 571 QUEUE_RW_ENTRY(queue_max_sectors, "max_sectors_kb");
 572 QUEUE_RO_ENTRY(queue_max_hw_sectors, "max_hw_sectors_kb");
 573 QUEUE_RO_ENTRY(queue_max_segments, "max_segments");
 574 QUEUE_RO_ENTRY(queue_max_integrity_segments, "max_integrity_segments");
 575 QUEUE_RO_ENTRY(queue_max_segment_size, "max_segment_size");
 576 QUEUE_RW_ENTRY(elv_iosched, "scheduler");
 577
 578 QUEUE_RO_ENTRY(queue_logical_block_size, "logical_block_size");
 579 QUEUE_RO_ENTRY(queue_physical_block_size, "physical_block_size");
 580 QUEUE_RO_ENTRY(queue_chunk_sectors, "chunk_sectors");
 581 QUEUE_RO_ENTRY(queue_io_min, "minimum_io_size");
 582 QUEUE_RO_ENTRY(queue_io_opt, "optimal_io_size");
 583
 584 QUEUE_RO_ENTRY(queue_max_discard_segments, "max_discard_segments");
 585 QUEUE_RO_ENTRY(queue_discard_granularity, "discard_granularity");
 586 QUEUE_RO_ENTRY(queue_discard_max_hw, "discard_max_hw_bytes");
 587 QUEUE_RW_ENTRY(queue_discard_max, "discard_max_bytes");
 588 QUEUE_RO_ENTRY(queue_discard_zeroes_data, "discard_zeroes_data");
 589
 590 QUEUE_RO_ENTRY(queue_write_same_max, "write_same_max_bytes");
 591 QUEUE_RO_ENTRY(queue_write_zeroes_max, "write_zeroes_max_bytes");
 592 QUEUE_RO_ENTRY(queue_zone_append_max, "zone_append_max_bytes");
 593 QUEUE_RO_ENTRY(queue_zone_write_granularity, "zone_write_granularity");
 594
 595 QUEUE_RO_ENTRY(queue_zoned, "zoned");
 596 QUEUE_RO_ENTRY(queue_nr_zones, "nr_zones");
 597 QUEUE_RO_ENTRY(queue_max_open_zones, "max_open_zones");
 598 QUEUE_RO_ENTRY(queue_max_active_zones, "max_active_zones");
 599
 600 QUEUE_RW_ENTRY(queue_nomerges, "nomerges");
 601 QUEUE_RW_ENTRY(queue_rq_affinity, "rq_affinity");
 602 QUEUE_RW_ENTRY(queue_poll, "io_poll");
 603 QUEUE_RW_ENTRY(queue_poll_delay, "io_poll_delay");
 604 QUEUE_RW_ENTRY(queue_wc, "write_cache");
 605 QUEUE_RO_ENTRY(queue_fua, "fua");
 606 QUEUE_RO_ENTRY(queue_dax, "dax");
 607 QUEUE_RW_ENTRY(queue_io_timeout, "io_timeout");
 608 QUEUE_RW_ENTRY(queue_wb_lat, "wbt_lat_usec");
 609 QUEUE_RO_ENTRY(queue_virt_boundary_mask, "virt_boundary_mask");
 610
 611 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 612 QUEUE_RW_ENTRY(blk_throtl_sample_time, "throttle_sample_time");
 613 #endif
 614
 615 /* legacy alias for logical_block_size: */
 616 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 617         .attr = {.name = "hw_sector_size", .mode = 0444 },
 618         .show = queue_logical_block_size_show,
 619 };
 620
 621 QUEUE_RW_ENTRY(queue_nonrot, "rotational");
 622 QUEUE_RW_ENTRY(queue_iostats, "iostats");
 623 QUEUE_RW_ENTRY(queue_random, "add_random");
 624 QUEUE_RW_ENTRY(queue_stable_writes, "stable_writes");
 625
 626 static struct attribute *queue_attrs[] = {
 627         &queue_requests_entry.attr,
 628         &queue_ra_entry.attr,
 629         &queue_max_hw_sectors_entry.attr,
 630         &queue_max_sectors_entry.attr,
 631         &queue_max_segments_entry.attr,
 632         &queue_max_discard_segments_entry.attr,
 633         &queue_max_integrity_segments_entry.attr,
 634         &queue_max_segment_size_entry.attr,
 635         &elv_iosched_entry.attr,
 636         &queue_hw_sector_size_entry.attr,
 637         &queue_logical_block_size_entry.attr,
 638         &queue_physical_block_size_entry.attr,
 639         &queue_chunk_sectors_entry.attr,
 640         &queue_io_min_entry.attr,
 641         &queue_io_opt_entry.attr,
 642         &queue_discard_granularity_entry.attr,
 643         &queue_discard_max_entry.attr,
 644         &queue_discard_max_hw_entry.attr,
 645         &queue_discard_zeroes_data_entry.attr,
 646         &queue_write_same_max_entry.attr,
 647         &queue_write_zeroes_max_entry.attr,
 648         &queue_zone_append_max_entry.attr,
 649         &queue_zone_write_granularity_entry.attr,
 650         &queue_nonrot_entry.attr,
 651         &queue_zoned_entry.attr,
 652         &queue_nr_zones_entry.attr,
 653         &queue_max_open_zones_entry.attr,
 654         &queue_max_active_zones_entry.attr,
 655         &queue_nomerges_entry.attr,
 656         &queue_rq_affinity_entry.attr,
 657         &queue_iostats_entry.attr,
 658         &queue_stable_writes_entry.attr,
 659         &queue_random_entry.attr,
 660         &queue_poll_entry.attr,
 661         &queue_wc_entry.attr,
 662         &queue_fua_entry.attr,
 663         &queue_dax_entry.attr,
 664         &queue_wb_lat_entry.attr,
 665         &queue_poll_delay_entry.attr,
 666         &queue_io_timeout_entry.attr,
 667 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 668         &blk_throtl_sample_time_entry.attr,
 669 #endif
 670         &queue_virt_boundary_mask_entry.attr,
 671         NULL,
 672 };
 673
 674 static umode_t queue_attr_visible(struct kobject *kobj, struct attribute *attr,
 675                                 int n)
 676 {
 677         struct request_queue *q =
 678                 container_of(kobj, struct request_queue, kobj);
 679
 680         if (attr == &queue_io_timeout_entry.attr &&
 681                 (!q->mq_ops || !q->mq_ops->timeout))
 682                         return 0;
 683
 684         if ((attr == &queue_max_open_zones_entry.attr ||
 685              attr == &queue_max_active_zones_entry.attr) &&
 686             !blk_queue_is_zoned(q))
 687                 return 0;
 688
 689         return attr->mode;
 690 }
 691
 692 static struct attribute_group queue_attr_group = {
 693         .attrs = queue_attrs,
 694         .is_visible = queue_attr_visible,
 695 };
 696
 697
 698 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 699
 700 static ssize_t
 701 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 702 {
 703         struct queue_sysfs_entry *entry = to_queue(attr);
 704         struct request_queue *q =
 705                 container_of(kobj, struct request_queue, kobj);
 706         ssize_t res;
 707
 708         if (!entry->show)
 709                 return -EIO;
 710         mutex_lock(&q->sysfs_lock);
 711         res = entry->show(q, page);
 712         mutex_unlock(&q->sysfs_lock);
 713         return res;
 714 }
 715
 716 static ssize_t
 717 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 718                     const char *page, size_t length)
 719 {
 720         struct queue_sysfs_entry *entry = to_queue(attr);
 721         struct request_queue *q;
 722         ssize_t res;
 723
 724         if (!entry->store)
 725                 return -EIO;
 726
 727         q = container_of(kobj, struct request_queue, kobj);
 728         mutex_lock(&q->sysfs_lock);
 729         res = entry->store(q, page, length);
 730         mutex_unlock(&q->sysfs_lock);
 731         return res;
 732 }
 733
 734 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 735 {
 736         struct request_queue *q = container_of(rcu_head, struct request_queue,
 737                                                rcu_head);
 738
 739         kmem_cache_free(blk_get_queue_kmem_cache(blk_queue_has_srcu(q)), q);
 740 }
 741
 742 /* Unconfigure the I/O scheduler and dissociate from the cgroup controller. */
 743 static void blk_exit_queue(struct request_queue *q)
 744 {
 745         /*
 746          * Since the I/O scheduler exit code may access cgroup information,
 747          * perform I/O scheduler exit before disassociating from the block
 748          * cgroup controller.
 749          */
 750         if (q->elevator) {
 751                 ioc_clear_queue(q);
 752                 elevator_exit(q);
 753         }
 754
 755         /*
 756          * Remove all references to @q from the block cgroup controller before
 757          * restoring @q->queue_lock to avoid that restoring this pointer causes
 758          * e.g. blkcg_print_blkgs() to crash.
 759          */
 760         blkcg_exit_queue(q);
 761 }
 762
 763 /**
 764  * blk_release_queue - releases all allocated resources of the request_queue
 765  * @kobj: pointer to a kobject, whose container is a request_queue
 766  *
 767  * This function releases all allocated resources of the request queue.
 768  *
 769  * The struct request_queue refcount is incremented with blk_get_queue() and
 770  * decremented with blk_put_queue(). Once the refcount reaches 0 this function
 771  * is called.
 772  *
 773  * For drivers that have a request_queue on a gendisk and added with
 774  * __device_add_disk() the refcount to request_queue will reach 0 with
 775  * the last put_disk() called by the driver. For drivers which don't use
 776  * __device_add_disk() this happens with blk_cleanup_queue().
 777  *
 778  * Drivers exist which depend on the release of the request_queue to be
 779  * synchronous, it should not be deferred.
 780  *
 781  * Context: can sleep
 782  */
 783 static void blk_release_queue(struct kobject *kobj)
 784 {
 785         struct request_queue *q =
 786                 container_of(kobj, struct request_queue, kobj);
 787
 788         might_sleep();
 789
 790         if (q->poll_stat)
 791                 blk_stat_remove_callback(q, q->poll_cb);
 792         blk_stat_free_callback(q->poll_cb);
 793
 794         blk_exit_queue(q);
 795
 796         blk_free_queue_stats(q->stats);
 797         kfree(q->poll_stat);
 798
 799         blk_queue_free_zone_bitmaps(q);
 800
 801         if (queue_is_mq(q))
 802                 blk_mq_release(q);
 803
 804         blk_trace_shutdown(q);
 805         mutex_lock(&q->debugfs_mutex);
 806         debugfs_remove_recursive(q->debugfs_dir);
 807         mutex_unlock(&q->debugfs_mutex);
 808
 809         if (queue_is_mq(q))
 810                 blk_mq_debugfs_unregister(q);
 811
 812         bioset_exit(&q->bio_split);
 813
 814         if (blk_queue_has_srcu(q))
 815                 cleanup_srcu_struct(q->srcu);
 816
 817         ida_simple_remove(&blk_queue_ida, q->id);
 818         call_rcu(&q->rcu_head, blk_free_queue_rcu);
 819 }
 820
 821 static const struct sysfs_ops queue_sysfs_ops = {
 822         .show   = queue_attr_show,
 823         .store  = queue_attr_store,
 824 };
 825
 826 struct kobj_type blk_queue_ktype = {
 827         .sysfs_ops      = &queue_sysfs_ops,
 828         .release        = blk_release_queue,
 829 };
 830
 831 /**
 832  * blk_register_queue - register a block layer queue with sysfs
 833  * @disk: Disk of which the request queue should be registered with sysfs.
 834  */
 835 int blk_register_queue(struct gendisk *disk)
 836 {
 837         int ret;
 838         struct device *dev = disk_to_dev(disk);
 839         struct request_queue *q = disk->queue;
 840
 841         ret = blk_trace_init_sysfs(dev);
 842         if (ret)
 843                 return ret;
 844
 845         mutex_lock(&q->sysfs_dir_lock);
 846
 847         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 848         if (ret < 0) {
 849                 blk_trace_remove_sysfs(dev);
 850                 goto unlock;
 851         }
 852
 853         ret = sysfs_create_group(&q->kobj, &queue_attr_group);
 854         if (ret) {
 855                 blk_trace_remove_sysfs(dev);
 856                 kobject_del(&q->kobj);
 857                 kobject_put(&dev->kobj);
 858                 goto unlock;
 859         }
 860
 861         mutex_lock(&q->debugfs_mutex);
 862         q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
 863                                             blk_debugfs_root);
 864         mutex_unlock(&q->debugfs_mutex);
 865
 866         if (queue_is_mq(q)) {
 867                 __blk_mq_register_dev(dev, q);
 868                 blk_mq_debugfs_register(q);
 869         }
 870
 871         mutex_lock(&q->sysfs_lock);
 872
 873         ret = disk_register_independent_access_ranges(disk, NULL);
 874         if (ret)
 875                 goto put_dev;
 876
 877         if (q->elevator) {
 878                 ret = elv_register_queue(q, false);
 879                 if (ret)
 880                         goto put_dev;
 881         }
 882
 883         blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);
 884         wbt_enable_default(q);
 885         blk_throtl_register_queue(q);
 886
 887         /* Now everything is ready and send out KOBJ_ADD uevent */
 888         kobject_uevent(&q->kobj, KOBJ_ADD);
 889         if (q->elevator)
 890                 kobject_uevent(&q->elevator->kobj, KOBJ_ADD);
 891         mutex_unlock(&q->sysfs_lock);
 892
 893 unlock:
 894         mutex_unlock(&q->sysfs_dir_lock);
 895
 896         /*
 897          * SCSI probing may synchronously create and destroy a lot of
 898          * request_queues for non-existent devices.  Shutting down a fully
 899          * functional queue takes measureable wallclock time as RCU grace
 900          * periods are involved.  To avoid excessive latency in these
 901          * cases, a request_queue starts out in a degraded mode which is
 902          * faster to shut down and is made fully functional here as
 903          * request_queues for non-existent devices never get registered.
 904          */
 905         if (!blk_queue_init_done(q)) {
 906                 blk_queue_flag_set(QUEUE_FLAG_INIT_DONE, q);
 907                 percpu_ref_switch_to_percpu(&q->q_usage_counter);
 908         }
 909
 910         return ret;
 911
 912 put_dev:
 913         disk_unregister_independent_access_ranges(disk);
 914         mutex_unlock(&q->sysfs_lock);
 915         mutex_unlock(&q->sysfs_dir_lock);
 916         kobject_del(&q->kobj);
 917         blk_trace_remove_sysfs(dev);
 918         kobject_put(&dev->kobj);
 919
 920         return ret;
 921 }
 922
 923 /**
 924  * blk_unregister_queue - counterpart of blk_register_queue()
 925  * @disk: Disk of which the request queue should be unregistered from sysfs.
 926  *
 927  * Note: the caller is responsible for guaranteeing that this function is called
 928  * after blk_register_queue() has finished.
 929  */
 930 void blk_unregister_queue(struct gendisk *disk)
 931 {
 932         struct request_queue *q = disk->queue;
 933
 934         if (WARN_ON(!q))
 935                 return;
 936
 937         /* Return early if disk->queue was never registered. */
 938         if (!blk_queue_registered(q))
 939                 return;
 940
 941         /*
 942          * Since sysfs_remove_dir() prevents adding new directory entries
 943          * before removal of existing entries starts, protect against
 944          * concurrent elv_iosched_store() calls.
 945          */
 946         mutex_lock(&q->sysfs_lock);
 947         blk_queue_flag_clear(QUEUE_FLAG_REGISTERED, q);
 948         mutex_unlock(&q->sysfs_lock);
 949
 950         mutex_lock(&q->sysfs_dir_lock);
 951         /*
 952          * Remove the sysfs attributes before unregistering the queue data
 953          * structures that can be modified through sysfs.
 954          */
 955         if (queue_is_mq(q))
 956                 blk_mq_unregister_dev(disk_to_dev(disk), q);
 957
 958         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 959         kobject_del(&q->kobj);
 960         blk_trace_remove_sysfs(disk_to_dev(disk));
 961
 962         mutex_lock(&q->sysfs_lock);
 963         if (q->elevator)
 964                 elv_unregister_queue(q);
 965         disk_unregister_independent_access_ranges(disk);
 966         mutex_unlock(&q->sysfs_lock);
 967         mutex_unlock(&q->sysfs_dir_lock);
 968
 969         kobject_put(&disk_to_dev(disk)->kobj);
 970 }