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 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 268 static ssize_t                                                          \
 269 queue_##name##_show(struct request_queue *q, char *page)                \
 270 {                                                                       \
 271         int bit;                                                        \
 272         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 273         return queue_var_show(neg ? !bit : bit, page);                  \
 274 }                                                                       \
 275 static ssize_t                                                          \
 276 queue_##name##_store(struct request_queue *q, const char *page, size_t count) \
 277 {                                                                       \
 278         unsigned long val;                                              \
 279         ssize_t ret;                                                    \
 280         ret = queue_var_store(&val, page, count);                       \
 281         if (ret < 0)                                                    \
 282                  return ret;                                            \
 283         if (neg)                                                        \
 284                 val = !val;                                             \
 285                                                                         \
 286         if (val)                                                        \
 287                 blk_queue_flag_set(QUEUE_FLAG_##flag, q);               \
 288         else                                                            \
 289                 blk_queue_flag_clear(QUEUE_FLAG_##flag, q);             \
 290         return ret;                                                     \
 291 }
 292
 293 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 294 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 295 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 296 QUEUE_SYSFS_BIT_FNS(stable_writes, STABLE_WRITES, 0);
 297 #undef QUEUE_SYSFS_BIT_FNS
 298
 299 static ssize_t queue_zoned_show(struct request_queue *q, char *page)
 300 {
 301         switch (blk_queue_zoned_model(q)) {
 302         case BLK_ZONED_HA:
 303                 return sprintf(page, "host-aware\n");
 304         case BLK_ZONED_HM:
 305                 return sprintf(page, "host-managed\n");
 306         default:
 307                 return sprintf(page, "none\n");
 308         }
 309 }
 310
 311 static ssize_t queue_nr_zones_show(struct request_queue *q, char *page)
 312 {
 313         return queue_var_show(blk_queue_nr_zones(q), page);
 314 }
 315
 316 static ssize_t queue_max_open_zones_show(struct request_queue *q, char *page)
 317 {
 318         return queue_var_show(queue_max_open_zones(q), page);
 319 }
 320
 321 static ssize_t queue_max_active_zones_show(struct request_queue *q, char *page)
 322 {
 323         return queue_var_show(queue_max_active_zones(q), page);
 324 }
 325
 326 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 327 {
 328         return queue_var_show((blk_queue_nomerges(q) << 1) |
 329                                blk_queue_noxmerges(q), page);
 330 }
 331
 332 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 333                                     size_t count)
 334 {
 335         unsigned long nm;
 336         ssize_t ret = queue_var_store(&nm, page, count);
 337
 338         if (ret < 0)
 339                 return ret;
 340
 341         blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 342         blk_queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 343         if (nm == 2)
 344                 blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 345         else if (nm)
 346                 blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 347
 348         return ret;
 349 }
 350
 351 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 352 {
 353         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 354         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 355
 356         return queue_var_show(set << force, page);
 357 }
 358
 359 static ssize_t
 360 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 361 {
 362         ssize_t ret = -EINVAL;
 363 #ifdef CONFIG_SMP
 364         unsigned long val;
 365
 366         ret = queue_var_store(&val, page, count);
 367         if (ret < 0)
 368                 return ret;
 369
 370         if (val == 2) {
 371                 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 372                 blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 373         } else if (val == 1) {
 374                 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 375                 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 376         } else if (val == 0) {
 377                 blk_queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 378                 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 379         }
 380 #endif
 381         return ret;
 382 }
 383
 384 static ssize_t queue_poll_delay_show(struct request_queue *q, char *page)
 385 {
 386         int val;
 387
 388         if (q->poll_nsec == BLK_MQ_POLL_CLASSIC)
 389                 val = BLK_MQ_POLL_CLASSIC;
 390         else
 391                 val = q->poll_nsec / 1000;
 392
 393         return sprintf(page, "%d\n", val);
 394 }
 395
 396 static ssize_t queue_poll_delay_store(struct request_queue *q, const char *page,
 397                                 size_t count)
 398 {
 399         int err, val;
 400
 401         if (!q->mq_ops || !q->mq_ops->poll)
 402                 return -EINVAL;
 403
 404         err = kstrtoint(page, 10, &val);
 405         if (err < 0)
 406                 return err;
 407
 408         if (val == BLK_MQ_POLL_CLASSIC)
 409                 q->poll_nsec = BLK_MQ_POLL_CLASSIC;
 410         else if (val >= 0)
 411                 q->poll_nsec = val * 1000;
 412         else
 413                 return -EINVAL;
 414
 415         return count;
 416 }
 417
 418 static ssize_t queue_poll_show(struct request_queue *q, char *page)
 419 {
 420         return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
 421 }
 422
 423 static ssize_t queue_poll_store(struct request_queue *q, const char *page,
 424                                 size_t count)
 425 {
 426         unsigned long poll_on;
 427         ssize_t ret;
 428
 429         if (!q->tag_set || q->tag_set->nr_maps <= HCTX_TYPE_POLL ||
 430             !q->tag_set->map[HCTX_TYPE_POLL].nr_queues)
 431                 return -EINVAL;
 432
 433         ret = queue_var_store(&poll_on, page, count);
 434         if (ret < 0)
 435                 return ret;
 436
 437         if (poll_on)
 438                 blk_queue_flag_set(QUEUE_FLAG_POLL, q);
 439         else
 440                 blk_queue_flag_clear(QUEUE_FLAG_POLL, q);
 441
 442         return ret;
 443 }
 444
 445 static ssize_t queue_io_timeout_show(struct request_queue *q, char *page)
 446 {
 447         return sprintf(page, "%u\n", jiffies_to_msecs(q->rq_timeout));
 448 }
 449
 450 static ssize_t queue_io_timeout_store(struct request_queue *q, const char *page,
 451                                   size_t count)
 452 {
 453         unsigned int val;
 454         int err;
 455
 456         err = kstrtou32(page, 10, &val);
 457         if (err || val == 0)
 458                 return -EINVAL;
 459
 460         blk_queue_rq_timeout(q, msecs_to_jiffies(val));
 461
 462         return count;
 463 }
 464
 465 static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
 466 {
 467         if (!wbt_rq_qos(q))
 468                 return -EINVAL;
 469
 470         return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));
 471 }
 472
 473 static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
 474                                   size_t count)
 475 {
 476         struct rq_qos *rqos;
 477         ssize_t ret;
 478         s64 val;
 479
 480         ret = queue_var_store64(&val, page);
 481         if (ret < 0)
 482                 return ret;
 483         if (val < -1)
 484                 return -EINVAL;
 485
 486         rqos = wbt_rq_qos(q);
 487         if (!rqos) {
 488                 ret = wbt_init(q);
 489                 if (ret)
 490                         return ret;
 491         }
 492
 493         if (val == -1)
 494                 val = wbt_default_latency_nsec(q);
 495         else if (val >= 0)
 496                 val *= 1000ULL;
 497
 498         if (wbt_get_min_lat(q) == val)
 499                 return count;
 500
 501         /*
 502          * Ensure that the queue is idled, in case the latency update
 503          * ends up either enabling or disabling wbt completely. We can't
 504          * have IO inflight if that happens.
 505          */
 506         blk_mq_freeze_queue(q);
 507         blk_mq_quiesce_queue(q);
 508
 509         wbt_set_min_lat(q, val);
 510
 511         blk_mq_unquiesce_queue(q);
 512         blk_mq_unfreeze_queue(q);
 513
 514         return count;
 515 }
 516
 517 static ssize_t queue_wc_show(struct request_queue *q, char *page)
 518 {
 519         if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
 520                 return sprintf(page, "write back\n");
 521
 522         return sprintf(page, "write through\n");
 523 }
 524
 525 static ssize_t queue_wc_store(struct request_queue *q, const char *page,
 526                               size_t count)
 527 {
 528         int set = -1;
 529
 530         if (!strncmp(page, "write back", 10))
 531                 set = 1;
 532         else if (!strncmp(page, "write through", 13) ||
 533                  !strncmp(page, "none", 4))
 534                 set = 0;
 535
 536         if (set == -1)
 537                 return -EINVAL;
 538
 539         if (set)
 540                 blk_queue_flag_set(QUEUE_FLAG_WC, q);
 541         else
 542                 blk_queue_flag_clear(QUEUE_FLAG_WC, q);
 543
 544         return count;
 545 }
 546
 547 static ssize_t queue_fua_show(struct request_queue *q, char *page)
 548 {
 549         return sprintf(page, "%u\n", test_bit(QUEUE_FLAG_FUA, &q->queue_flags));
 550 }
 551
 552 static ssize_t queue_dax_show(struct request_queue *q, char *page)
 553 {
 554         return queue_var_show(blk_queue_dax(q), page);
 555 }
 556
 557 #define QUEUE_RO_ENTRY(_prefix, _name)                  \
 558 static struct queue_sysfs_entry _prefix##_entry = {     \
 559         .attr   = { .name = _name, .mode = 0444 },      \
 560         .show   = _prefix##_show,                       \
 561 };
 562
 563 #define QUEUE_RW_ENTRY(_prefix, _name)                  \
 564 static struct queue_sysfs_entry _prefix##_entry = {     \
 565         .attr   = { .name = _name, .mode = 0644 },      \
 566         .show   = _prefix##_show,                       \
 567         .store  = _prefix##_store,                      \
 568 };
 569
 570 QUEUE_RW_ENTRY(queue_requests, "nr_requests");
 571 QUEUE_RW_ENTRY(queue_ra, "read_ahead_kb");
 572 QUEUE_RW_ENTRY(queue_max_sectors, "max_sectors_kb");
 573 QUEUE_RO_ENTRY(queue_max_hw_sectors, "max_hw_sectors_kb");
 574 QUEUE_RO_ENTRY(queue_max_segments, "max_segments");
 575 QUEUE_RO_ENTRY(queue_max_integrity_segments, "max_integrity_segments");
 576 QUEUE_RO_ENTRY(queue_max_segment_size, "max_segment_size");
 577 QUEUE_RW_ENTRY(elv_iosched, "scheduler");
 578
 579 QUEUE_RO_ENTRY(queue_logical_block_size, "logical_block_size");
 580 QUEUE_RO_ENTRY(queue_physical_block_size, "physical_block_size");
 581 QUEUE_RO_ENTRY(queue_chunk_sectors, "chunk_sectors");
 582 QUEUE_RO_ENTRY(queue_io_min, "minimum_io_size");
 583 QUEUE_RO_ENTRY(queue_io_opt, "optimal_io_size");
 584
 585 QUEUE_RO_ENTRY(queue_max_discard_segments, "max_discard_segments");
 586 QUEUE_RO_ENTRY(queue_discard_granularity, "discard_granularity");
 587 QUEUE_RO_ENTRY(queue_discard_max_hw, "discard_max_hw_bytes");
 588 QUEUE_RW_ENTRY(queue_discard_max, "discard_max_bytes");
 589 QUEUE_RO_ENTRY(queue_discard_zeroes_data, "discard_zeroes_data");
 590
 591 QUEUE_RO_ENTRY(queue_write_same_max, "write_same_max_bytes");
 592 QUEUE_RO_ENTRY(queue_write_zeroes_max, "write_zeroes_max_bytes");
 593 QUEUE_RO_ENTRY(queue_zone_append_max, "zone_append_max_bytes");
 594 QUEUE_RO_ENTRY(queue_zone_write_granularity, "zone_write_granularity");
 595
 596 QUEUE_RO_ENTRY(queue_zoned, "zoned");
 597 QUEUE_RO_ENTRY(queue_nr_zones, "nr_zones");
 598 QUEUE_RO_ENTRY(queue_max_open_zones, "max_open_zones");
 599 QUEUE_RO_ENTRY(queue_max_active_zones, "max_active_zones");
 600
 601 QUEUE_RW_ENTRY(queue_nomerges, "nomerges");
 602 QUEUE_RW_ENTRY(queue_rq_affinity, "rq_affinity");
 603 QUEUE_RW_ENTRY(queue_poll, "io_poll");
 604 QUEUE_RW_ENTRY(queue_poll_delay, "io_poll_delay");
 605 QUEUE_RW_ENTRY(queue_wc, "write_cache");
 606 QUEUE_RO_ENTRY(queue_fua, "fua");
 607 QUEUE_RO_ENTRY(queue_dax, "dax");
 608 QUEUE_RW_ENTRY(queue_io_timeout, "io_timeout");
 609 QUEUE_RW_ENTRY(queue_wb_lat, "wbt_lat_usec");
 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         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
 738         percpu_ref_exit(&q->q_usage_counter);
 739         kmem_cache_free(blk_requestq_cachep, 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, q->elevator);
 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          * Since the cgroup code may dereference the @q->backing_dev_info
 764          * pointer, only decrease its reference count after having removed the
 765          * association with the block cgroup controller.
 766          */
 767         bdi_put(q->backing_dev_info);
 768 }
 769
 770 /**
 771  * blk_release_queue - releases all allocated resources of the request_queue
 772  * @kobj: pointer to a kobject, whose container is a request_queue
 773  *
 774  * This function releases all allocated resources of the request queue.
 775  *
 776  * The struct request_queue refcount is incremented with blk_get_queue() and
 777  * decremented with blk_put_queue(). Once the refcount reaches 0 this function
 778  * is called.
 779  *
 780  * For drivers that have a request_queue on a gendisk and added with
 781  * __device_add_disk() the refcount to request_queue will reach 0 with
 782  * the last put_disk() called by the driver. For drivers which don't use
 783  * __device_add_disk() this happens with blk_cleanup_queue().
 784  *
 785  * Drivers exist which depend on the release of the request_queue to be
 786  * synchronous, it should not be deferred.
 787  *
 788  * Context: can sleep
 789  */
 790 static void blk_release_queue(struct kobject *kobj)
 791 {
 792         struct request_queue *q =
 793                 container_of(kobj, struct request_queue, kobj);
 794
 795         might_sleep();
 796
 797         if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags))
 798                 blk_stat_remove_callback(q, q->poll_cb);
 799         blk_stat_free_callback(q->poll_cb);
 800
 801         blk_free_queue_stats(q->stats);
 802
 803         if (queue_is_mq(q)) {
 804                 struct blk_mq_hw_ctx *hctx;
 805                 int i;
 806
 807                 cancel_delayed_work_sync(&q->requeue_work);
 808
 809                 queue_for_each_hw_ctx(q, hctx, i)
 810                         cancel_delayed_work_sync(&hctx->run_work);
 811         }
 812
 813         blk_exit_queue(q);
 814
 815         blk_queue_free_zone_bitmaps(q);
 816
 817         if (queue_is_mq(q))
 818                 blk_mq_release(q);
 819
 820         blk_trace_shutdown(q);
 821         mutex_lock(&q->debugfs_mutex);
 822         debugfs_remove_recursive(q->debugfs_dir);
 823         mutex_unlock(&q->debugfs_mutex);
 824
 825         if (queue_is_mq(q))
 826                 blk_mq_debugfs_unregister(q);
 827
 828         bioset_exit(&q->bio_split);
 829
 830         ida_simple_remove(&blk_queue_ida, q->id);
 831         call_rcu(&q->rcu_head, blk_free_queue_rcu);
 832 }
 833
 834 static const struct sysfs_ops queue_sysfs_ops = {
 835         .show   = queue_attr_show,
 836         .store  = queue_attr_store,
 837 };
 838
 839 struct kobj_type blk_queue_ktype = {
 840         .sysfs_ops      = &queue_sysfs_ops,
 841         .release        = blk_release_queue,
 842 };
 843
 844 /**
 845  * blk_register_queue - register a block layer queue with sysfs
 846  * @disk: Disk of which the request queue should be registered with sysfs.
 847  */
 848 int blk_register_queue(struct gendisk *disk)
 849 {
 850         int ret;
 851         struct device *dev = disk_to_dev(disk);
 852         struct request_queue *q = disk->queue;
 853
 854         if (WARN_ON(!q))
 855                 return -ENXIO;
 856
 857         WARN_ONCE(blk_queue_registered(q),
 858                   "%s is registering an already registered queue\n",
 859                   kobject_name(&dev->kobj));
 860
 861         /*
 862          * SCSI probing may synchronously create and destroy a lot of
 863          * request_queues for non-existent devices.  Shutting down a fully
 864          * functional queue takes measureable wallclock time as RCU grace
 865          * periods are involved.  To avoid excessive latency in these
 866          * cases, a request_queue starts out in a degraded mode which is
 867          * faster to shut down and is made fully functional here as
 868          * request_queues for non-existent devices never get registered.
 869          */
 870         if (!blk_queue_init_done(q)) {
 871                 blk_queue_flag_set(QUEUE_FLAG_INIT_DONE, q);
 872                 percpu_ref_switch_to_percpu(&q->q_usage_counter);
 873         }
 874
 875         blk_queue_update_readahead(q);
 876
 877         ret = blk_trace_init_sysfs(dev);
 878         if (ret)
 879                 return ret;
 880
 881         mutex_lock(&q->sysfs_dir_lock);
 882
 883         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 884         if (ret < 0) {
 885                 blk_trace_remove_sysfs(dev);
 886                 goto unlock;
 887         }
 888
 889         ret = sysfs_create_group(&q->kobj, &queue_attr_group);
 890         if (ret) {
 891                 blk_trace_remove_sysfs(dev);
 892                 kobject_del(&q->kobj);
 893                 kobject_put(&dev->kobj);
 894                 goto unlock;
 895         }
 896
 897         mutex_lock(&q->debugfs_mutex);
 898         q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
 899                                             blk_debugfs_root);
 900         mutex_unlock(&q->debugfs_mutex);
 901
 902         if (queue_is_mq(q)) {
 903                 __blk_mq_register_dev(dev, q);
 904                 blk_mq_debugfs_register(q);
 905         }
 906
 907         mutex_lock(&q->sysfs_lock);
 908         if (q->elevator) {
 909                 ret = elv_register_queue(q, false);
 910                 if (ret) {
 911                         mutex_unlock(&q->sysfs_lock);
 912                         mutex_unlock(&q->sysfs_dir_lock);
 913                         kobject_del(&q->kobj);
 914                         blk_trace_remove_sysfs(dev);
 915                         kobject_put(&dev->kobj);
 916                         return ret;
 917                 }
 918         }
 919
 920         blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);
 921         wbt_enable_default(q);
 922         blk_throtl_register_queue(q);
 923
 924         /* Now everything is ready and send out KOBJ_ADD uevent */
 925         kobject_uevent(&q->kobj, KOBJ_ADD);
 926         if (q->elevator)
 927                 kobject_uevent(&q->elevator->kobj, KOBJ_ADD);
 928         mutex_unlock(&q->sysfs_lock);
 929
 930         ret = 0;
 931 unlock:
 932         mutex_unlock(&q->sysfs_dir_lock);
 933         return ret;
 934 }
 935 EXPORT_SYMBOL_GPL(blk_register_queue);
 936
 937 /**
 938  * blk_unregister_queue - counterpart of blk_register_queue()
 939  * @disk: Disk of which the request queue should be unregistered from sysfs.
 940  *
 941  * Note: the caller is responsible for guaranteeing that this function is called
 942  * after blk_register_queue() has finished.
 943  */
 944 void blk_unregister_queue(struct gendisk *disk)
 945 {
 946         struct request_queue *q = disk->queue;
 947
 948         if (WARN_ON(!q))
 949                 return;
 950
 951         /* Return early if disk->queue was never registered. */
 952         if (!blk_queue_registered(q))
 953                 return;
 954
 955         /*
 956          * Since sysfs_remove_dir() prevents adding new directory entries
 957          * before removal of existing entries starts, protect against
 958          * concurrent elv_iosched_store() calls.
 959          */
 960         mutex_lock(&q->sysfs_lock);
 961         blk_queue_flag_clear(QUEUE_FLAG_REGISTERED, q);
 962         mutex_unlock(&q->sysfs_lock);
 963
 964         mutex_lock(&q->sysfs_dir_lock);
 965         /*
 966          * Remove the sysfs attributes before unregistering the queue data
 967          * structures that can be modified through sysfs.
 968          */
 969         if (queue_is_mq(q))
 970                 blk_mq_unregister_dev(disk_to_dev(disk), q);
 971         blk_trace_remove_sysfs(disk_to_dev(disk));
 972
 973         mutex_lock(&q->sysfs_lock);
 974         if (q->elevator)
 975                 elv_unregister_queue(q);
 976         mutex_unlock(&q->sysfs_lock);
 977
 978         /* Now that we've deleted all child objects, we can delete the queue. */
 979         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 980         kobject_del(&q->kobj);
 981
 982         mutex_unlock(&q->sysfs_dir_lock);
 983
 984         kobject_put(&disk_to_dev(disk)->kobj);
 985 }