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