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-wbt.h"
  20
  21 struct queue_sysfs_entry {
  22         struct attribute attr;
  23         ssize_t (*show)(struct request_queue *, char *);
  24         ssize_t (*store)(struct request_queue *, const char *, size_t);
  25 };
  26
  27 static ssize_t
  28 queue_var_show(unsigned long var, char *page)
  29 {
  30         return sprintf(page, "%lu\n", var);
  31 }
  32
  33 static ssize_t
  34 queue_var_store(unsigned long *var, const char *page, size_t count)
  35 {
  36         int err;
  37         unsigned long v;
  38
  39         err = kstrtoul(page, 10, &v);
  40         if (err || v > UINT_MAX)
  41                 return -EINVAL;
  42
  43         *var = v;
  44
  45         return count;
  46 }
  47
  48 static ssize_t queue_var_store64(s64 *var, const char *page)
  49 {
  50         int err;
  51         s64 v;
  52
  53         err = kstrtos64(page, 10, &v);
  54         if (err < 0)
  55                 return err;
  56
  57         *var = v;
  58         return 0;
  59 }
  60
  61 static ssize_t queue_requests_show(struct request_queue *q, char *page)
  62 {
  63         return queue_var_show(q->nr_requests, page);
  64 }
  65
  66 static ssize_t
  67 queue_requests_store(struct request_queue *q, const char *page, size_t count)
  68 {
  69         unsigned long nr;
  70         int ret, err;
  71
  72         if (!queue_is_mq(q))
  73                 return -EINVAL;
  74
  75         ret = queue_var_store(&nr, page, count);
  76         if (ret < 0)
  77                 return ret;
  78
  79         if (nr < BLKDEV_MIN_RQ)
  80                 nr = BLKDEV_MIN_RQ;
  81
  82         err = blk_mq_update_nr_requests(q, nr);
  83         if (err)
  84                 return err;
  85
  86         return ret;
  87 }
  88
  89 static ssize_t queue_ra_show(struct request_queue *q, char *page)
  90 {
  91         unsigned long ra_kb = q->backing_dev_info->ra_pages <<
  92                                         (PAGE_SHIFT - 10);
  93
  94         return queue_var_show(ra_kb, page);
  95 }
  96
  97 static ssize_t
  98 queue_ra_store(struct request_queue *q, const char *page, size_t count)
  99 {
 100         unsigned long ra_kb;
 101         ssize_t ret = queue_var_store(&ra_kb, page, count);
 102
 103         if (ret < 0)
 104                 return ret;
 105
 106         q->backing_dev_info->ra_pages = ra_kb >> (PAGE_SHIFT - 10);
 107
 108         return ret;
 109 }
 110
 111 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
 112 {
 113         int max_sectors_kb = queue_max_sectors(q) >> 1;
 114
 115         return queue_var_show(max_sectors_kb, page);
 116 }
 117
 118 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
 119 {
 120         return queue_var_show(queue_max_segments(q), page);
 121 }
 122
 123 static ssize_t queue_max_discard_segments_show(struct request_queue *q,
 124                 char *page)
 125 {
 126         return queue_var_show(queue_max_discard_segments(q), page);
 127 }
 128
 129 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
 130 {
 131         return queue_var_show(q->limits.max_integrity_segments, page);
 132 }
 133
 134 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 135 {
 136         return queue_var_show(queue_max_segment_size(q), page);
 137 }
 138
 139 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 140 {
 141         return queue_var_show(queue_logical_block_size(q), page);
 142 }
 143
 144 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 145 {
 146         return queue_var_show(queue_physical_block_size(q), page);
 147 }
 148
 149 static ssize_t queue_chunk_sectors_show(struct request_queue *q, char *page)
 150 {
 151         return queue_var_show(q->limits.chunk_sectors, page);
 152 }
 153
 154 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 155 {
 156         return queue_var_show(queue_io_min(q), page);
 157 }
 158
 159 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 160 {
 161         return queue_var_show(queue_io_opt(q), page);
 162 }
 163
 164 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 165 {
 166         return queue_var_show(q->limits.discard_granularity, page);
 167 }
 168
 169 static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
 170 {
 171
 172         return sprintf(page, "%llu\n",
 173                 (unsigned long long)q->limits.max_hw_discard_sectors << 9);
 174 }
 175
 176 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 177 {
 178         return sprintf(page, "%llu\n",
 179                        (unsigned long long)q->limits.max_discard_sectors << 9);
 180 }
 181
 182 static ssize_t queue_discard_max_store(struct request_queue *q,
 183                                        const char *page, size_t count)
 184 {
 185         unsigned long max_discard;
 186         ssize_t ret = queue_var_store(&max_discard, page, count);
 187
 188         if (ret < 0)
 189                 return ret;
 190
 191         if (max_discard & (q->limits.discard_granularity - 1))
 192                 return -EINVAL;
 193
 194         max_discard >>= 9;
 195         if (max_discard > UINT_MAX)
 196                 return -EINVAL;
 197
 198         if (max_discard > q->limits.max_hw_discard_sectors)
 199                 max_discard = q->limits.max_hw_discard_sectors;
 200
 201         q->limits.max_discard_sectors = max_discard;
 202         return ret;
 203 }
 204
 205 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 206 {
 207         return queue_var_show(0, page);
 208 }
 209
 210 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
 211 {
 212         return sprintf(page, "%llu\n",
 213                 (unsigned long long)q->limits.max_write_same_sectors << 9);
 214 }
 215
 216 static ssize_t queue_write_zeroes_max_show(struct request_queue *q, char *page)
 217 {
 218         return sprintf(page, "%llu\n",
 219                 (unsigned long long)q->limits.max_write_zeroes_sectors << 9);
 220 }
 221
 222 static ssize_t queue_zone_write_granularity_show(struct request_queue *q,
 223                                                  char *page)
 224 {
 225         return queue_var_show(queue_zone_write_granularity(q), page);
 226 }
 227
 228 static ssize_t queue_zone_append_max_show(struct request_queue *q, char *page)
 229 {
 230         unsigned long long max_sectors = q->limits.max_zone_append_sectors;
 231
 232         return sprintf(page, "%llu\n", max_sectors << SECTOR_SHIFT);
 233 }
 234
 235 static ssize_t
 236 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 237 {
 238         unsigned long max_sectors_kb,
 239                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 240                         page_kb = 1 << (PAGE_SHIFT - 10);
 241         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 242
 243         if (ret < 0)
 244                 return ret;
 245
 246         max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, (unsigned long)
 247                                          q->limits.max_dev_sectors >> 1);
 248
 249         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 250                 return -EINVAL;
 251
 252         spin_lock_irq(&q->queue_lock);
 253         q->limits.max_sectors = max_sectors_kb << 1;
 254         q->backing_dev_info->io_pages = max_sectors_kb >> (PAGE_SHIFT - 10);
 255         spin_unlock_irq(&q->queue_lock);
 256
 257         return ret;
 258 }
 259
 260 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 261 {
 262         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 263
 264         return queue_var_show(max_hw_sectors_kb, page);
 265 }
 266
 267 static ssize_t queue_virt_boundary_mask_show(struct request_queue *q, char *page)
 268 {
 269         return queue_var_show(q->limits.virt_boundary_mask, page);
 270 }
 271
 272 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 273 static ssize_t                                                          \
 274 queue_##name##_show(struct request_queue *q, char *page)                \
 275 {                                                                       \
 276         int bit;                                                        \
 277         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 278         return queue_var_show(neg ? !bit : bit, page);                  \
 279 }                                                                       \
 280 static ssize_t                                                          \
 281 queue_##name##_store(struct request_queue *q, const char *page, size_t count) \
 282 {                                                                       \
 283         unsigned long val;                                              \
 284         ssize_t ret;                                                    \
 285         ret = queue_var_store(&val, page, count);                       \
 286         if (ret < 0)                                                    \
 287                  return ret;                                            \
 288         if (neg)                                                        \
 289                 val = !val;                                             \
 290                                                                         \
 291         if (val)                                                        \
 292                 blk_queue_flag_set(QUEUE_FLAG_##flag, q);               \
 293         else                                                            \
 294                 blk_queue_flag_clear(QUEUE_FLAG_##flag, q);             \
 295         return ret;                                                     \
 296 }
 297
 298 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 299 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 300 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 301 QUEUE_SYSFS_BIT_FNS(stable_writes, STABLE_WRITES, 0);
 302 #undef QUEUE_SYSFS_BIT_FNS
 303
 304 static ssize_t queue_zoned_show(struct request_queue *q, char *page)
 305 {
 306         switch (blk_queue_zoned_model(q)) {
 307         case BLK_ZONED_HA:
 308                 return sprintf(page, "host-aware\n");
 309         case BLK_ZONED_HM:
 310                 return sprintf(page, "host-managed\n");
 311         default:
 312                 return sprintf(page, "none\n");
 313         }
 314 }
 315
 316 static ssize_t queue_nr_zones_show(struct request_queue *q, char *page)
 317 {
 318         return queue_var_show(blk_queue_nr_zones(q), page);
 319 }
 320
 321 static ssize_t queue_max_open_zones_show(struct request_queue *q, char *page)
 322 {
 323         return queue_var_show(queue_max_open_zones(q), page);
 324 }
 325
 326 static ssize_t queue_max_active_zones_show(struct request_queue *q, char *page)
 327 {
 328         return queue_var_show(queue_max_active_zones(q), page);
 329 }
 330
 331 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 332 {
 333         return queue_var_show((blk_queue_nomerges(q) << 1) |
 334                                blk_queue_noxmerges(q), page);
 335 }
 336
 337 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 338                                     size_t count)
 339 {
 340         unsigned long nm;
 341         ssize_t ret = queue_var_store(&nm, page, count);
 342
 343         if (ret < 0)
 344                 return ret;
 345
 346         blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 347         blk_queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 348         if (nm == 2)
 349                 blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 350         else if (nm)
 351                 blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 352
 353         return ret;
 354 }
 355
 356 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 357 {
 358         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 359         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 360
 361         return queue_var_show(set << force, page);
 362 }
 363
 364 static ssize_t
 365 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 366 {
 367         ssize_t ret = -EINVAL;
 368 #ifdef CONFIG_SMP
 369         unsigned long val;
 370
 371         ret = queue_var_store(&val, page, count);
 372         if (ret < 0)
 373                 return ret;
 374
 375         if (val == 2) {
 376                 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 377                 blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 378         } else if (val == 1) {
 379                 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 380                 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 381         } else if (val == 0) {
 382                 blk_queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 383                 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 384         }
 385 #endif
 386         return ret;
 387 }
 388
 389 static ssize_t queue_poll_delay_show(struct request_queue *q, char *page)
 390 {
 391         int val;
 392
 393         if (q->poll_nsec == BLK_MQ_POLL_CLASSIC)
 394                 val = BLK_MQ_POLL_CLASSIC;
 395         else
 396                 val = q->poll_nsec / 1000;
 397
 398         return sprintf(page, "%d\n", val);
 399 }
 400
 401 static ssize_t queue_poll_delay_store(struct request_queue *q, const char *page,
 402                                 size_t count)
 403 {
 404         int err, val;
 405
 406         if (!q->mq_ops || !q->mq_ops->poll)
 407                 return -EINVAL;
 408
 409         err = kstrtoint(page, 10, &val);
 410         if (err < 0)
 411                 return err;
 412
 413         if (val == BLK_MQ_POLL_CLASSIC)
 414                 q->poll_nsec = BLK_MQ_POLL_CLASSIC;
 415         else if (val >= 0)
 416                 q->poll_nsec = val * 1000;
 417         else
 418                 return -EINVAL;
 419
 420         return count;
 421 }
 422
 423 static ssize_t queue_poll_show(struct request_queue *q, char *page)
 424 {
 425         return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
 426 }
 427
 428 static ssize_t queue_poll_store(struct request_queue *q, const char *page,
 429                                 size_t count)
 430 {
 431         unsigned long poll_on;
 432         ssize_t ret;
 433
 434         if (!q->tag_set || q->tag_set->nr_maps <= HCTX_TYPE_POLL ||
 435             !q->tag_set->map[HCTX_TYPE_POLL].nr_queues)
 436                 return -EINVAL;
 437
 438         ret = queue_var_store(&poll_on, page, count);
 439         if (ret < 0)
 440                 return ret;
 441
 442         if (poll_on) {
 443                 blk_queue_flag_set(QUEUE_FLAG_POLL, q);
 444         } else {
 445                 blk_mq_freeze_queue(q);
 446                 blk_queue_flag_clear(QUEUE_FLAG_POLL, q);
 447                 blk_mq_unfreeze_queue(q);
 448         }
 449
 450         return ret;
 451 }
 452
 453 static ssize_t queue_io_timeout_show(struct request_queue *q, char *page)
 454 {
 455         return sprintf(page, "%u\n", jiffies_to_msecs(q->rq_timeout));
 456 }
 457
 458 static ssize_t queue_io_timeout_store(struct request_queue *q, const char *page,
 459                                   size_t count)
 460 {
 461         unsigned int val;
 462         int err;
 463
 464         err = kstrtou32(page, 10, &val);
 465         if (err || val == 0)
 466                 return -EINVAL;
 467
 468         blk_queue_rq_timeout(q, msecs_to_jiffies(val));
 469
 470         return count;
 471 }
 472
 473 static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
 474 {
 475         if (!wbt_rq_qos(q))
 476                 return -EINVAL;
 477
 478         return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));
 479 }
 480
 481 static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
 482                                   size_t count)
 483 {
 484         struct rq_qos *rqos;
 485         ssize_t ret;
 486         s64 val;
 487
 488         ret = queue_var_store64(&val, page);
 489         if (ret < 0)
 490                 return ret;
 491         if (val < -1)
 492                 return -EINVAL;
 493
 494         rqos = wbt_rq_qos(q);
 495         if (!rqos) {
 496                 ret = wbt_init(q);
 497                 if (ret)
 498                         return ret;
 499         }
 500
 501         if (val == -1)
 502                 val = wbt_default_latency_nsec(q);
 503         else if (val >= 0)
 504                 val *= 1000ULL;
 505
 506         if (wbt_get_min_lat(q) == val)
 507                 return count;
 508
 509         /*
 510          * Ensure that the queue is idled, in case the latency update
 511          * ends up either enabling or disabling wbt completely. We can't
 512          * have IO inflight if that happens.
 513          */
 514         blk_mq_freeze_queue(q);
 515         blk_mq_quiesce_queue(q);
 516
 517         wbt_set_min_lat(q, val);
 518
 519         blk_mq_unquiesce_queue(q);
 520         blk_mq_unfreeze_queue(q);
 521
 522         return count;
 523 }
 524
 525 static ssize_t queue_wc_show(struct request_queue *q, char *page)
 526 {
 527         if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
 528                 return sprintf(page, "write back\n");
 529
 530         return sprintf(page, "write through\n");
 531 }
 532
 533 static ssize_t queue_wc_store(struct request_queue *q, const char *page,
 534                               size_t count)
 535 {
 536         int set = -1;
 537
 538         if (!strncmp(page, "write back", 10))
 539                 set = 1;
 540         else if (!strncmp(page, "write through", 13) ||
 541                  !strncmp(page, "none", 4))
 542                 set = 0;
 543
 544         if (set == -1)
 545                 return -EINVAL;
 546
 547         if (set)
 548                 blk_queue_flag_set(QUEUE_FLAG_WC, q);
 549         else
 550                 blk_queue_flag_clear(QUEUE_FLAG_WC, q);
 551
 552         return count;
 553 }
 554
 555 static ssize_t queue_fua_show(struct request_queue *q, char *page)
 556 {
 557         return sprintf(page, "%u\n", test_bit(QUEUE_FLAG_FUA, &q->queue_flags));
 558 }
 559
 560 static ssize_t queue_dax_show(struct request_queue *q, char *page)
 561 {
 562         return queue_var_show(blk_queue_dax(q), page);
 563 }
 564
 565 #define QUEUE_RO_ENTRY(_prefix, _name)                  \
 566 static struct queue_sysfs_entry _prefix##_entry = {     \
 567         .attr   = { .name = _name, .mode = 0444 },      \
 568         .show   = _prefix##_show,                       \
 569 };
 570
 571 #define QUEUE_RW_ENTRY(_prefix, _name)                  \
 572 static struct queue_sysfs_entry _prefix##_entry = {     \
 573         .attr   = { .name = _name, .mode = 0644 },      \
 574         .show   = _prefix##_show,                       \
 575         .store  = _prefix##_store,                      \
 576 };
 577
 578 QUEUE_RW_ENTRY(queue_requests, "nr_requests");
 579 QUEUE_RW_ENTRY(queue_ra, "read_ahead_kb");
 580 QUEUE_RW_ENTRY(queue_max_sectors, "max_sectors_kb");
 581 QUEUE_RO_ENTRY(queue_max_hw_sectors, "max_hw_sectors_kb");
 582 QUEUE_RO_ENTRY(queue_max_segments, "max_segments");
 583 QUEUE_RO_ENTRY(queue_max_integrity_segments, "max_integrity_segments");
 584 QUEUE_RO_ENTRY(queue_max_segment_size, "max_segment_size");
 585 QUEUE_RW_ENTRY(elv_iosched, "scheduler");
 586
 587 QUEUE_RO_ENTRY(queue_logical_block_size, "logical_block_size");
 588 QUEUE_RO_ENTRY(queue_physical_block_size, "physical_block_size");
 589 QUEUE_RO_ENTRY(queue_chunk_sectors, "chunk_sectors");
 590 QUEUE_RO_ENTRY(queue_io_min, "minimum_io_size");
 591 QUEUE_RO_ENTRY(queue_io_opt, "optimal_io_size");
 592
 593 QUEUE_RO_ENTRY(queue_max_discard_segments, "max_discard_segments");
 594 QUEUE_RO_ENTRY(queue_discard_granularity, "discard_granularity");
 595 QUEUE_RO_ENTRY(queue_discard_max_hw, "discard_max_hw_bytes");
 596 QUEUE_RW_ENTRY(queue_discard_max, "discard_max_bytes");
 597 QUEUE_RO_ENTRY(queue_discard_zeroes_data, "discard_zeroes_data");
 598
 599 QUEUE_RO_ENTRY(queue_write_same_max, "write_same_max_bytes");
 600 QUEUE_RO_ENTRY(queue_write_zeroes_max, "write_zeroes_max_bytes");
 601 QUEUE_RO_ENTRY(queue_zone_append_max, "zone_append_max_bytes");
 602 QUEUE_RO_ENTRY(queue_zone_write_granularity, "zone_write_granularity");
 603
 604 QUEUE_RO_ENTRY(queue_zoned, "zoned");
 605 QUEUE_RO_ENTRY(queue_nr_zones, "nr_zones");
 606 QUEUE_RO_ENTRY(queue_max_open_zones, "max_open_zones");
 607 QUEUE_RO_ENTRY(queue_max_active_zones, "max_active_zones");
 608
 609 QUEUE_RW_ENTRY(queue_nomerges, "nomerges");
 610 QUEUE_RW_ENTRY(queue_rq_affinity, "rq_affinity");
 611 QUEUE_RW_ENTRY(queue_poll, "io_poll");
 612 QUEUE_RW_ENTRY(queue_poll_delay, "io_poll_delay");
 613 QUEUE_RW_ENTRY(queue_wc, "write_cache");
 614 QUEUE_RO_ENTRY(queue_fua, "fua");
 615 QUEUE_RO_ENTRY(queue_dax, "dax");
 616 QUEUE_RW_ENTRY(queue_io_timeout, "io_timeout");
 617 QUEUE_RW_ENTRY(queue_wb_lat, "wbt_lat_usec");
 618 QUEUE_RO_ENTRY(queue_virt_boundary_mask, "virt_boundary_mask");
 619
 620 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 621 QUEUE_RW_ENTRY(blk_throtl_sample_time, "throttle_sample_time");
 622 #endif
 623
 624 /* legacy alias for logical_block_size: */
 625 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 626         .attr = {.name = "hw_sector_size", .mode = 0444 },
 627         .show = queue_logical_block_size_show,
 628 };
 629
 630 QUEUE_RW_ENTRY(queue_nonrot, "rotational");
 631 QUEUE_RW_ENTRY(queue_iostats, "iostats");
 632 QUEUE_RW_ENTRY(queue_random, "add_random");
 633 QUEUE_RW_ENTRY(queue_stable_writes, "stable_writes");
 634
 635 static struct attribute *queue_attrs[] = {
 636         &queue_requests_entry.attr,
 637         &queue_ra_entry.attr,
 638         &queue_max_hw_sectors_entry.attr,
 639         &queue_max_sectors_entry.attr,
 640         &queue_max_segments_entry.attr,
 641         &queue_max_discard_segments_entry.attr,
 642         &queue_max_integrity_segments_entry.attr,
 643         &queue_max_segment_size_entry.attr,
 644         &elv_iosched_entry.attr,
 645         &queue_hw_sector_size_entry.attr,
 646         &queue_logical_block_size_entry.attr,
 647         &queue_physical_block_size_entry.attr,
 648         &queue_chunk_sectors_entry.attr,
 649         &queue_io_min_entry.attr,
 650         &queue_io_opt_entry.attr,
 651         &queue_discard_granularity_entry.attr,
 652         &queue_discard_max_entry.attr,
 653         &queue_discard_max_hw_entry.attr,
 654         &queue_discard_zeroes_data_entry.attr,
 655         &queue_write_same_max_entry.attr,
 656         &queue_write_zeroes_max_entry.attr,
 657         &queue_zone_append_max_entry.attr,
 658         &queue_zone_write_granularity_entry.attr,
 659         &queue_nonrot_entry.attr,
 660         &queue_zoned_entry.attr,
 661         &queue_nr_zones_entry.attr,
 662         &queue_max_open_zones_entry.attr,
 663         &queue_max_active_zones_entry.attr,
 664         &queue_nomerges_entry.attr,
 665         &queue_rq_affinity_entry.attr,
 666         &queue_iostats_entry.attr,
 667         &queue_stable_writes_entry.attr,
 668         &queue_random_entry.attr,
 669         &queue_poll_entry.attr,
 670         &queue_wc_entry.attr,
 671         &queue_fua_entry.attr,
 672         &queue_dax_entry.attr,
 673         &queue_wb_lat_entry.attr,
 674         &queue_poll_delay_entry.attr,
 675         &queue_io_timeout_entry.attr,
 676 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 677         &blk_throtl_sample_time_entry.attr,
 678 #endif
 679         &queue_virt_boundary_mask_entry.attr,
 680         NULL,
 681 };
 682
 683 static umode_t queue_attr_visible(struct kobject *kobj, struct attribute *attr,
 684                                 int n)
 685 {
 686         struct request_queue *q =
 687                 container_of(kobj, struct request_queue, kobj);
 688
 689         if (attr == &queue_io_timeout_entry.attr &&
 690                 (!q->mq_ops || !q->mq_ops->timeout))
 691                         return 0;
 692
 693         if ((attr == &queue_max_open_zones_entry.attr ||
 694              attr == &queue_max_active_zones_entry.attr) &&
 695             !blk_queue_is_zoned(q))
 696                 return 0;
 697
 698         return attr->mode;
 699 }
 700
 701 static struct attribute_group queue_attr_group = {
 702         .attrs = queue_attrs,
 703         .is_visible = queue_attr_visible,
 704 };
 705
 706
 707 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 708
 709 static ssize_t
 710 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 711 {
 712         struct queue_sysfs_entry *entry = to_queue(attr);
 713         struct request_queue *q =
 714                 container_of(kobj, struct request_queue, kobj);
 715         ssize_t res;
 716
 717         if (!entry->show)
 718                 return -EIO;
 719         mutex_lock(&q->sysfs_lock);
 720         res = entry->show(q, page);
 721         mutex_unlock(&q->sysfs_lock);
 722         return res;
 723 }
 724
 725 static ssize_t
 726 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 727                     const char *page, size_t length)
 728 {
 729         struct queue_sysfs_entry *entry = to_queue(attr);
 730         struct request_queue *q;
 731         ssize_t res;
 732
 733         if (!entry->store)
 734                 return -EIO;
 735
 736         q = container_of(kobj, struct request_queue, kobj);
 737         mutex_lock(&q->sysfs_lock);
 738         res = entry->store(q, page, length);
 739         mutex_unlock(&q->sysfs_lock);
 740         return res;
 741 }
 742
 743 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 744 {
 745         struct request_queue *q = container_of(rcu_head, struct request_queue,
 746                                                rcu_head);
 747         kmem_cache_free(blk_requestq_cachep, q);
 748 }
 749
 750 /* Unconfigure the I/O scheduler and dissociate from the cgroup controller. */
 751 static void blk_exit_queue(struct request_queue *q)
 752 {
 753         /*
 754          * Since the I/O scheduler exit code may access cgroup information,
 755          * perform I/O scheduler exit before disassociating from the block
 756          * cgroup controller.
 757          */
 758         if (q->elevator) {
 759                 ioc_clear_queue(q);
 760                 __elevator_exit(q, q->elevator);
 761         }
 762
 763         /*
 764          * Remove all references to @q from the block cgroup controller before
 765          * restoring @q->queue_lock to avoid that restoring this pointer causes
 766          * e.g. blkcg_print_blkgs() to crash.
 767          */
 768         blkcg_exit_queue(q);
 769
 770         /*
 771          * Since the cgroup code may dereference the @q->backing_dev_info
 772          * pointer, only decrease its reference count after having removed the
 773          * association with the block cgroup controller.
 774          */
 775         bdi_put(q->backing_dev_info);
 776 }
 777
 778 /**
 779  * blk_release_queue - releases all allocated resources of the request_queue
 780  * @kobj: pointer to a kobject, whose container is a request_queue
 781  *
 782  * This function releases all allocated resources of the request queue.
 783  *
 784  * The struct request_queue refcount is incremented with blk_get_queue() and
 785  * decremented with blk_put_queue(). Once the refcount reaches 0 this function
 786  * is called.
 787  *
 788  * For drivers that have a request_queue on a gendisk and added with
 789  * __device_add_disk() the refcount to request_queue will reach 0 with
 790  * the last put_disk() called by the driver. For drivers which don't use
 791  * __device_add_disk() this happens with blk_cleanup_queue().
 792  *
 793  * Drivers exist which depend on the release of the request_queue to be
 794  * synchronous, it should not be deferred.
 795  *
 796  * Context: can sleep
 797  */
 798 static void blk_release_queue(struct kobject *kobj)
 799 {
 800         struct request_queue *q =
 801                 container_of(kobj, struct request_queue, kobj);
 802
 803         might_sleep();
 804
 805         if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags))
 806                 blk_stat_remove_callback(q, q->poll_cb);
 807         blk_stat_free_callback(q->poll_cb);
 808
 809         blk_free_queue_stats(q->stats);
 810
 811         if (queue_is_mq(q)) {
 812                 struct blk_mq_hw_ctx *hctx;
 813                 int i;
 814
 815                 cancel_delayed_work_sync(&q->requeue_work);
 816
 817                 queue_for_each_hw_ctx(q, hctx, i)
 818                         cancel_delayed_work_sync(&hctx->run_work);
 819         }
 820
 821         blk_exit_queue(q);
 822
 823         blk_queue_free_zone_bitmaps(q);
 824
 825         if (queue_is_mq(q))
 826                 blk_mq_release(q);
 827
 828         blk_trace_shutdown(q);
 829         mutex_lock(&q->debugfs_mutex);
 830         debugfs_remove_recursive(q->debugfs_dir);
 831         mutex_unlock(&q->debugfs_mutex);
 832
 833         if (queue_is_mq(q))
 834                 blk_mq_debugfs_unregister(q);
 835
 836         bioset_exit(&q->bio_split);
 837
 838         ida_simple_remove(&blk_queue_ida, q->id);
 839         call_rcu(&q->rcu_head, blk_free_queue_rcu);
 840 }
 841
 842 static const struct sysfs_ops queue_sysfs_ops = {
 843         .show   = queue_attr_show,
 844         .store  = queue_attr_store,
 845 };
 846
 847 struct kobj_type blk_queue_ktype = {
 848         .sysfs_ops      = &queue_sysfs_ops,
 849         .release        = blk_release_queue,
 850 };
 851
 852 /**
 853  * blk_register_queue - register a block layer queue with sysfs
 854  * @disk: Disk of which the request queue should be registered with sysfs.
 855  */
 856 int blk_register_queue(struct gendisk *disk)
 857 {
 858         int ret;
 859         struct device *dev = disk_to_dev(disk);
 860         struct request_queue *q = disk->queue;
 861
 862         if (WARN_ON(!q))
 863                 return -ENXIO;
 864
 865         WARN_ONCE(blk_queue_registered(q),
 866                   "%s is registering an already registered queue\n",
 867                   kobject_name(&dev->kobj));
 868
 869         blk_queue_update_readahead(q);
 870
 871         ret = blk_trace_init_sysfs(dev);
 872         if (ret)
 873                 return ret;
 874
 875         mutex_lock(&q->sysfs_dir_lock);
 876
 877         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 878         if (ret < 0) {
 879                 blk_trace_remove_sysfs(dev);
 880                 goto unlock;
 881         }
 882
 883         ret = sysfs_create_group(&q->kobj, &queue_attr_group);
 884         if (ret) {
 885                 blk_trace_remove_sysfs(dev);
 886                 kobject_del(&q->kobj);
 887                 kobject_put(&dev->kobj);
 888                 goto unlock;
 889         }
 890
 891         mutex_lock(&q->debugfs_mutex);
 892         q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
 893                                             blk_debugfs_root);
 894         mutex_unlock(&q->debugfs_mutex);
 895
 896         if (queue_is_mq(q)) {
 897                 __blk_mq_register_dev(dev, q);
 898                 blk_mq_debugfs_register(q);
 899         }
 900
 901         mutex_lock(&q->sysfs_lock);
 902         if (q->elevator) {
 903                 ret = elv_register_queue(q, false);
 904                 if (ret) {
 905                         mutex_unlock(&q->sysfs_lock);
 906                         mutex_unlock(&q->sysfs_dir_lock);
 907                         kobject_del(&q->kobj);
 908                         blk_trace_remove_sysfs(dev);
 909                         kobject_put(&dev->kobj);
 910                         return ret;
 911                 }
 912         }
 913
 914         blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);
 915         wbt_enable_default(q);
 916         blk_throtl_register_queue(q);
 917
 918         /* Now everything is ready and send out KOBJ_ADD uevent */
 919         kobject_uevent(&q->kobj, KOBJ_ADD);
 920         if (q->elevator)
 921                 kobject_uevent(&q->elevator->kobj, KOBJ_ADD);
 922         mutex_unlock(&q->sysfs_lock);
 923
 924         ret = 0;
 925 unlock:
 926         mutex_unlock(&q->sysfs_dir_lock);
 927
 928         /*
 929          * SCSI probing may synchronously create and destroy a lot of
 930          * request_queues for non-existent devices.  Shutting down a fully
 931          * functional queue takes measureable wallclock time as RCU grace
 932          * periods are involved.  To avoid excessive latency in these
 933          * cases, a request_queue starts out in a degraded mode which is
 934          * faster to shut down and is made fully functional here as
 935          * request_queues for non-existent devices never get registered.
 936          */
 937         if (!blk_queue_init_done(q)) {
 938                 blk_queue_flag_set(QUEUE_FLAG_INIT_DONE, q);
 939                 percpu_ref_switch_to_percpu(&q->q_usage_counter);
 940         }
 941
 942         return ret;
 943 }
 944 EXPORT_SYMBOL_GPL(blk_register_queue);
 945
 946 /**
 947  * blk_unregister_queue - counterpart of blk_register_queue()
 948  * @disk: Disk of which the request queue should be unregistered from sysfs.
 949  *
 950  * Note: the caller is responsible for guaranteeing that this function is called
 951  * after blk_register_queue() has finished.
 952  */
 953 void blk_unregister_queue(struct gendisk *disk)
 954 {
 955         struct request_queue *q = disk->queue;
 956
 957         if (WARN_ON(!q))
 958                 return;
 959
 960         /* Return early if disk->queue was never registered. */
 961         if (!blk_queue_registered(q))
 962                 return;
 963
 964         /*
 965          * Since sysfs_remove_dir() prevents adding new directory entries
 966          * before removal of existing entries starts, protect against
 967          * concurrent elv_iosched_store() calls.
 968          */
 969         mutex_lock(&q->sysfs_lock);
 970         blk_queue_flag_clear(QUEUE_FLAG_REGISTERED, q);
 971         mutex_unlock(&q->sysfs_lock);
 972
 973         mutex_lock(&q->sysfs_dir_lock);
 974         /*
 975          * Remove the sysfs attributes before unregistering the queue data
 976          * structures that can be modified through sysfs.
 977          */
 978         if (queue_is_mq(q))
 979                 blk_mq_unregister_dev(disk_to_dev(disk), q);
 980
 981         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 982         kobject_del(&q->kobj);
 983         blk_trace_remove_sysfs(disk_to_dev(disk));
 984
 985         mutex_lock(&q->sysfs_lock);
 986         if (q->elevator)
 987                 elv_unregister_queue(q);
 988         mutex_unlock(&q->sysfs_lock);
 989         mutex_unlock(&q->sysfs_dir_lock);
 990
 991         kobject_put(&disk_to_dev(disk)->kobj);
 992 }