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
  15 #include "blk.h"
  16 #include "blk-mq.h"
  17 #include "blk-mq-debugfs.h"
  18 #include "blk-wbt.h"
  19
  20 struct queue_sysfs_entry {
  21         struct attribute attr;
  22         ssize_t (*show)(struct request_queue *, char *);
  23         ssize_t (*store)(struct request_queue *, const char *, size_t);
  24 };
  25
  26 static ssize_t
  27 queue_var_show(unsigned long var, char *page)
  28 {
  29         return sprintf(page, "%lu\n", var);
  30 }
  31
  32 static ssize_t
  33 queue_var_store(unsigned long *var, const char *page, size_t count)
  34 {
  35         int err;
  36         unsigned long v;
  37
  38         err = kstrtoul(page, 10, &v);
  39         if (err || v > UINT_MAX)
  40                 return -EINVAL;
  41
  42         *var = v;
  43
  44         return count;
  45 }
  46
  47 static ssize_t queue_var_store64(s64 *var, const char *page)
  48 {
  49         int err;
  50         s64 v;
  51
  52         err = kstrtos64(page, 10, &v);
  53         if (err < 0)
  54                 return err;
  55
  56         *var = v;
  57         return 0;
  58 }
  59
  60 static ssize_t queue_requests_show(struct request_queue *q, char *page)
  61 {
  62         return queue_var_show(q->nr_requests, (page));
  63 }
  64
  65 static ssize_t
  66 queue_requests_store(struct request_queue *q, const char *page, size_t count)
  67 {
  68         unsigned long nr;
  69         int ret, err;
  70
  71         if (!queue_is_mq(q))
  72                 return -EINVAL;
  73
  74         ret = queue_var_store(&nr, page, count);
  75         if (ret < 0)
  76                 return ret;
  77
  78         if (nr < BLKDEV_MIN_RQ)
  79                 nr = BLKDEV_MIN_RQ;
  80
  81         err = blk_mq_update_nr_requests(q, nr);
  82         if (err)
  83                 return err;
  84
  85         return ret;
  86 }
  87
  88 static ssize_t queue_ra_show(struct request_queue *q, char *page)
  89 {
  90         unsigned long ra_kb = q->backing_dev_info->ra_pages <<
  91                                         (PAGE_SHIFT - 10);
  92
  93         return queue_var_show(ra_kb, (page));
  94 }
  95
  96 static ssize_t
  97 queue_ra_store(struct request_queue *q, const char *page, size_t count)
  98 {
  99         unsigned long ra_kb;
 100         ssize_t ret = queue_var_store(&ra_kb, page, count);
 101
 102         if (ret < 0)
 103                 return ret;
 104
 105         q->backing_dev_info->ra_pages = ra_kb >> (PAGE_SHIFT - 10);
 106
 107         return ret;
 108 }
 109
 110 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
 111 {
 112         int max_sectors_kb = queue_max_sectors(q) >> 1;
 113
 114         return queue_var_show(max_sectors_kb, (page));
 115 }
 116
 117 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
 118 {
 119         return queue_var_show(queue_max_segments(q), (page));
 120 }
 121
 122 static ssize_t queue_max_discard_segments_show(struct request_queue *q,
 123                 char *page)
 124 {
 125         return queue_var_show(queue_max_discard_segments(q), (page));
 126 }
 127
 128 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
 129 {
 130         return queue_var_show(q->limits.max_integrity_segments, (page));
 131 }
 132
 133 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 134 {
 135         return queue_var_show(queue_max_segment_size(q), (page));
 136 }
 137
 138 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 139 {
 140         return queue_var_show(queue_logical_block_size(q), page);
 141 }
 142
 143 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 144 {
 145         return queue_var_show(queue_physical_block_size(q), page);
 146 }
 147
 148 static ssize_t queue_chunk_sectors_show(struct request_queue *q, char *page)
 149 {
 150         return queue_var_show(q->limits.chunk_sectors, page);
 151 }
 152
 153 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 154 {
 155         return queue_var_show(queue_io_min(q), page);
 156 }
 157
 158 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 159 {
 160         return queue_var_show(queue_io_opt(q), page);
 161 }
 162
 163 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 164 {
 165         return queue_var_show(q->limits.discard_granularity, page);
 166 }
 167
 168 static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
 169 {
 170
 171         return sprintf(page, "%llu\n",
 172                 (unsigned long long)q->limits.max_hw_discard_sectors << 9);
 173 }
 174
 175 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 176 {
 177         return sprintf(page, "%llu\n",
 178                        (unsigned long long)q->limits.max_discard_sectors << 9);
 179 }
 180
 181 static ssize_t queue_discard_max_store(struct request_queue *q,
 182                                        const char *page, size_t count)
 183 {
 184         unsigned long max_discard;
 185         ssize_t ret = queue_var_store(&max_discard, page, count);
 186
 187         if (ret < 0)
 188                 return ret;
 189
 190         if (max_discard & (q->limits.discard_granularity - 1))
 191                 return -EINVAL;
 192
 193         max_discard >>= 9;
 194         if (max_discard > UINT_MAX)
 195                 return -EINVAL;
 196
 197         if (max_discard > q->limits.max_hw_discard_sectors)
 198                 max_discard = q->limits.max_hw_discard_sectors;
 199
 200         q->limits.max_discard_sectors = max_discard;
 201         return ret;
 202 }
 203
 204 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 205 {
 206         return queue_var_show(0, page);
 207 }
 208
 209 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
 210 {
 211         return sprintf(page, "%llu\n",
 212                 (unsigned long long)q->limits.max_write_same_sectors << 9);
 213 }
 214
 215 static ssize_t queue_write_zeroes_max_show(struct request_queue *q, char *page)
 216 {
 217         return sprintf(page, "%llu\n",
 218                 (unsigned long long)q->limits.max_write_zeroes_sectors << 9);
 219 }
 220
 221 static ssize_t
 222 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 223 {
 224         unsigned long max_sectors_kb,
 225                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 226                         page_kb = 1 << (PAGE_SHIFT - 10);
 227         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 228
 229         if (ret < 0)
 230                 return ret;
 231
 232         max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, (unsigned long)
 233                                          q->limits.max_dev_sectors >> 1);
 234
 235         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 236                 return -EINVAL;
 237
 238         spin_lock_irq(&q->queue_lock);
 239         q->limits.max_sectors = max_sectors_kb << 1;
 240         q->backing_dev_info->io_pages = max_sectors_kb >> (PAGE_SHIFT - 10);
 241         spin_unlock_irq(&q->queue_lock);
 242
 243         return ret;
 244 }
 245
 246 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 247 {
 248         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 249
 250         return queue_var_show(max_hw_sectors_kb, (page));
 251 }
 252
 253 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 254 static ssize_t                                                          \
 255 queue_show_##name(struct request_queue *q, char *page)                  \
 256 {                                                                       \
 257         int bit;                                                        \
 258         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 259         return queue_var_show(neg ? !bit : bit, page);                  \
 260 }                                                                       \
 261 static ssize_t                                                          \
 262 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
 263 {                                                                       \
 264         unsigned long val;                                              \
 265         ssize_t ret;                                                    \
 266         ret = queue_var_store(&val, page, count);                       \
 267         if (ret < 0)                                                    \
 268                  return ret;                                            \
 269         if (neg)                                                        \
 270                 val = !val;                                             \
 271                                                                         \
 272         if (val)                                                        \
 273                 blk_queue_flag_set(QUEUE_FLAG_##flag, q);               \
 274         else                                                            \
 275                 blk_queue_flag_clear(QUEUE_FLAG_##flag, q);             \
 276         return ret;                                                     \
 277 }
 278
 279 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 280 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 281 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 282 #undef QUEUE_SYSFS_BIT_FNS
 283
 284 static ssize_t queue_zoned_show(struct request_queue *q, char *page)
 285 {
 286         switch (blk_queue_zoned_model(q)) {
 287         case BLK_ZONED_HA:
 288                 return sprintf(page, "host-aware\n");
 289         case BLK_ZONED_HM:
 290                 return sprintf(page, "host-managed\n");
 291         default:
 292                 return sprintf(page, "none\n");
 293         }
 294 }
 295
 296 static ssize_t queue_nr_zones_show(struct request_queue *q, char *page)
 297 {
 298         return queue_var_show(blk_queue_nr_zones(q), page);
 299 }
 300
 301 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 302 {
 303         return queue_var_show((blk_queue_nomerges(q) << 1) |
 304                                blk_queue_noxmerges(q), page);
 305 }
 306
 307 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 308                                     size_t count)
 309 {
 310         unsigned long nm;
 311         ssize_t ret = queue_var_store(&nm, page, count);
 312
 313         if (ret < 0)
 314                 return ret;
 315
 316         blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 317         blk_queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 318         if (nm == 2)
 319                 blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 320         else if (nm)
 321                 blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 322
 323         return ret;
 324 }
 325
 326 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 327 {
 328         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 329         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 330
 331         return queue_var_show(set << force, page);
 332 }
 333
 334 static ssize_t
 335 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 336 {
 337         ssize_t ret = -EINVAL;
 338 #ifdef CONFIG_SMP
 339         unsigned long val;
 340
 341         ret = queue_var_store(&val, page, count);
 342         if (ret < 0)
 343                 return ret;
 344
 345         if (val == 2) {
 346                 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 347                 blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 348         } else if (val == 1) {
 349                 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 350                 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 351         } else if (val == 0) {
 352                 blk_queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 353                 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 354         }
 355 #endif
 356         return ret;
 357 }
 358
 359 static ssize_t queue_poll_delay_show(struct request_queue *q, char *page)
 360 {
 361         int val;
 362
 363         if (q->poll_nsec == -1)
 364                 val = -1;
 365         else
 366                 val = q->poll_nsec / 1000;
 367
 368         return sprintf(page, "%d\n", val);
 369 }
 370
 371 static ssize_t queue_poll_delay_store(struct request_queue *q, const char *page,
 372                                 size_t count)
 373 {
 374         int err, val;
 375
 376         if (!q->mq_ops || !q->mq_ops->poll)
 377                 return -EINVAL;
 378
 379         err = kstrtoint(page, 10, &val);
 380         if (err < 0)
 381                 return err;
 382
 383         if (val == -1)
 384                 q->poll_nsec = -1;
 385         else
 386                 q->poll_nsec = val * 1000;
 387
 388         return count;
 389 }
 390
 391 static ssize_t queue_poll_show(struct request_queue *q, char *page)
 392 {
 393         return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
 394 }
 395
 396 static ssize_t queue_poll_store(struct request_queue *q, const char *page,
 397                                 size_t count)
 398 {
 399         unsigned long poll_on;
 400         ssize_t ret;
 401
 402         if (!q->tag_set || q->tag_set->nr_maps <= HCTX_TYPE_POLL ||
 403             !q->tag_set->map[HCTX_TYPE_POLL].nr_queues)
 404                 return -EINVAL;
 405
 406         ret = queue_var_store(&poll_on, page, count);
 407         if (ret < 0)
 408                 return ret;
 409
 410         if (poll_on)
 411                 blk_queue_flag_set(QUEUE_FLAG_POLL, q);
 412         else
 413                 blk_queue_flag_clear(QUEUE_FLAG_POLL, q);
 414
 415         return ret;
 416 }
 417
 418 static ssize_t queue_io_timeout_show(struct request_queue *q, char *page)
 419 {
 420         return sprintf(page, "%u\n", jiffies_to_msecs(q->rq_timeout));
 421 }
 422
 423 static ssize_t queue_io_timeout_store(struct request_queue *q, const char *page,
 424                                   size_t count)
 425 {
 426         unsigned int val;
 427         int err;
 428
 429         err = kstrtou32(page, 10, &val);
 430         if (err || val == 0)
 431                 return -EINVAL;
 432
 433         blk_queue_rq_timeout(q, msecs_to_jiffies(val));
 434
 435         return count;
 436 }
 437
 438 static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
 439 {
 440         if (!wbt_rq_qos(q))
 441                 return -EINVAL;
 442
 443         return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));
 444 }
 445
 446 static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
 447                                   size_t count)
 448 {
 449         struct rq_qos *rqos;
 450         ssize_t ret;
 451         s64 val;
 452
 453         ret = queue_var_store64(&val, page);
 454         if (ret < 0)
 455                 return ret;
 456         if (val < -1)
 457                 return -EINVAL;
 458
 459         rqos = wbt_rq_qos(q);
 460         if (!rqos) {
 461                 ret = wbt_init(q);
 462                 if (ret)
 463                         return ret;
 464         }
 465
 466         if (val == -1)
 467                 val = wbt_default_latency_nsec(q);
 468         else if (val >= 0)
 469                 val *= 1000ULL;
 470
 471         /*
 472          * Ensure that the queue is idled, in case the latency update
 473          * ends up either enabling or disabling wbt completely. We can't
 474          * have IO inflight if that happens.
 475          */
 476         blk_mq_freeze_queue(q);
 477         blk_mq_quiesce_queue(q);
 478
 479         wbt_set_min_lat(q, val);
 480         wbt_update_limits(q);
 481
 482         blk_mq_unquiesce_queue(q);
 483         blk_mq_unfreeze_queue(q);
 484
 485         return count;
 486 }
 487
 488 static ssize_t queue_wc_show(struct request_queue *q, char *page)
 489 {
 490         if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
 491                 return sprintf(page, "write back\n");
 492
 493         return sprintf(page, "write through\n");
 494 }
 495
 496 static ssize_t queue_wc_store(struct request_queue *q, const char *page,
 497                               size_t count)
 498 {
 499         int set = -1;
 500
 501         if (!strncmp(page, "write back", 10))
 502                 set = 1;
 503         else if (!strncmp(page, "write through", 13) ||
 504                  !strncmp(page, "none", 4))
 505                 set = 0;
 506
 507         if (set == -1)
 508                 return -EINVAL;
 509
 510         if (set)
 511                 blk_queue_flag_set(QUEUE_FLAG_WC, q);
 512         else
 513                 blk_queue_flag_clear(QUEUE_FLAG_WC, q);
 514
 515         return count;
 516 }
 517
 518 static ssize_t queue_fua_show(struct request_queue *q, char *page)
 519 {
 520         return sprintf(page, "%u\n", test_bit(QUEUE_FLAG_FUA, &q->queue_flags));
 521 }
 522
 523 static ssize_t queue_dax_show(struct request_queue *q, char *page)
 524 {
 525         return queue_var_show(blk_queue_dax(q), page);
 526 }
 527
 528 static struct queue_sysfs_entry queue_requests_entry = {
 529         .attr = {.name = "nr_requests", .mode = 0644 },
 530         .show = queue_requests_show,
 531         .store = queue_requests_store,
 532 };
 533
 534 static struct queue_sysfs_entry queue_ra_entry = {
 535         .attr = {.name = "read_ahead_kb", .mode = 0644 },
 536         .show = queue_ra_show,
 537         .store = queue_ra_store,
 538 };
 539
 540 static struct queue_sysfs_entry queue_max_sectors_entry = {
 541         .attr = {.name = "max_sectors_kb", .mode = 0644 },
 542         .show = queue_max_sectors_show,
 543         .store = queue_max_sectors_store,
 544 };
 545
 546 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 547         .attr = {.name = "max_hw_sectors_kb", .mode = 0444 },
 548         .show = queue_max_hw_sectors_show,
 549 };
 550
 551 static struct queue_sysfs_entry queue_max_segments_entry = {
 552         .attr = {.name = "max_segments", .mode = 0444 },
 553         .show = queue_max_segments_show,
 554 };
 555
 556 static struct queue_sysfs_entry queue_max_discard_segments_entry = {
 557         .attr = {.name = "max_discard_segments", .mode = 0444 },
 558         .show = queue_max_discard_segments_show,
 559 };
 560
 561 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
 562         .attr = {.name = "max_integrity_segments", .mode = 0444 },
 563         .show = queue_max_integrity_segments_show,
 564 };
 565
 566 static struct queue_sysfs_entry queue_max_segment_size_entry = {
 567         .attr = {.name = "max_segment_size", .mode = 0444 },
 568         .show = queue_max_segment_size_show,
 569 };
 570
 571 static struct queue_sysfs_entry queue_iosched_entry = {
 572         .attr = {.name = "scheduler", .mode = 0644 },
 573         .show = elv_iosched_show,
 574         .store = elv_iosched_store,
 575 };
 576
 577 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 578         .attr = {.name = "hw_sector_size", .mode = 0444 },
 579         .show = queue_logical_block_size_show,
 580 };
 581
 582 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 583         .attr = {.name = "logical_block_size", .mode = 0444 },
 584         .show = queue_logical_block_size_show,
 585 };
 586
 587 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 588         .attr = {.name = "physical_block_size", .mode = 0444 },
 589         .show = queue_physical_block_size_show,
 590 };
 591
 592 static struct queue_sysfs_entry queue_chunk_sectors_entry = {
 593         .attr = {.name = "chunk_sectors", .mode = 0444 },
 594         .show = queue_chunk_sectors_show,
 595 };
 596
 597 static struct queue_sysfs_entry queue_io_min_entry = {
 598         .attr = {.name = "minimum_io_size", .mode = 0444 },
 599         .show = queue_io_min_show,
 600 };
 601
 602 static struct queue_sysfs_entry queue_io_opt_entry = {
 603         .attr = {.name = "optimal_io_size", .mode = 0444 },
 604         .show = queue_io_opt_show,
 605 };
 606
 607 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 608         .attr = {.name = "discard_granularity", .mode = 0444 },
 609         .show = queue_discard_granularity_show,
 610 };
 611
 612 static struct queue_sysfs_entry queue_discard_max_hw_entry = {
 613         .attr = {.name = "discard_max_hw_bytes", .mode = 0444 },
 614         .show = queue_discard_max_hw_show,
 615 };
 616
 617 static struct queue_sysfs_entry queue_discard_max_entry = {
 618         .attr = {.name = "discard_max_bytes", .mode = 0644 },
 619         .show = queue_discard_max_show,
 620         .store = queue_discard_max_store,
 621 };
 622
 623 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 624         .attr = {.name = "discard_zeroes_data", .mode = 0444 },
 625         .show = queue_discard_zeroes_data_show,
 626 };
 627
 628 static struct queue_sysfs_entry queue_write_same_max_entry = {
 629         .attr = {.name = "write_same_max_bytes", .mode = 0444 },
 630         .show = queue_write_same_max_show,
 631 };
 632
 633 static struct queue_sysfs_entry queue_write_zeroes_max_entry = {
 634         .attr = {.name = "write_zeroes_max_bytes", .mode = 0444 },
 635         .show = queue_write_zeroes_max_show,
 636 };
 637
 638 static struct queue_sysfs_entry queue_nonrot_entry = {
 639         .attr = {.name = "rotational", .mode = 0644 },
 640         .show = queue_show_nonrot,
 641         .store = queue_store_nonrot,
 642 };
 643
 644 static struct queue_sysfs_entry queue_zoned_entry = {
 645         .attr = {.name = "zoned", .mode = 0444 },
 646         .show = queue_zoned_show,
 647 };
 648
 649 static struct queue_sysfs_entry queue_nr_zones_entry = {
 650         .attr = {.name = "nr_zones", .mode = 0444 },
 651         .show = queue_nr_zones_show,
 652 };
 653
 654 static struct queue_sysfs_entry queue_nomerges_entry = {
 655         .attr = {.name = "nomerges", .mode = 0644 },
 656         .show = queue_nomerges_show,
 657         .store = queue_nomerges_store,
 658 };
 659
 660 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 661         .attr = {.name = "rq_affinity", .mode = 0644 },
 662         .show = queue_rq_affinity_show,
 663         .store = queue_rq_affinity_store,
 664 };
 665
 666 static struct queue_sysfs_entry queue_iostats_entry = {
 667         .attr = {.name = "iostats", .mode = 0644 },
 668         .show = queue_show_iostats,
 669         .store = queue_store_iostats,
 670 };
 671
 672 static struct queue_sysfs_entry queue_random_entry = {
 673         .attr = {.name = "add_random", .mode = 0644 },
 674         .show = queue_show_random,
 675         .store = queue_store_random,
 676 };
 677
 678 static struct queue_sysfs_entry queue_poll_entry = {
 679         .attr = {.name = "io_poll", .mode = 0644 },
 680         .show = queue_poll_show,
 681         .store = queue_poll_store,
 682 };
 683
 684 static struct queue_sysfs_entry queue_poll_delay_entry = {
 685         .attr = {.name = "io_poll_delay", .mode = 0644 },
 686         .show = queue_poll_delay_show,
 687         .store = queue_poll_delay_store,
 688 };
 689
 690 static struct queue_sysfs_entry queue_wc_entry = {
 691         .attr = {.name = "write_cache", .mode = 0644 },
 692         .show = queue_wc_show,
 693         .store = queue_wc_store,
 694 };
 695
 696 static struct queue_sysfs_entry queue_fua_entry = {
 697         .attr = {.name = "fua", .mode = 0444 },
 698         .show = queue_fua_show,
 699 };
 700
 701 static struct queue_sysfs_entry queue_dax_entry = {
 702         .attr = {.name = "dax", .mode = 0444 },
 703         .show = queue_dax_show,
 704 };
 705
 706 static struct queue_sysfs_entry queue_io_timeout_entry = {
 707         .attr = {.name = "io_timeout", .mode = 0644 },
 708         .show = queue_io_timeout_show,
 709         .store = queue_io_timeout_store,
 710 };
 711
 712 static struct queue_sysfs_entry queue_wb_lat_entry = {
 713         .attr = {.name = "wbt_lat_usec", .mode = 0644 },
 714         .show = queue_wb_lat_show,
 715         .store = queue_wb_lat_store,
 716 };
 717
 718 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 719 static struct queue_sysfs_entry throtl_sample_time_entry = {
 720         .attr = {.name = "throttle_sample_time", .mode = 0644 },
 721         .show = blk_throtl_sample_time_show,
 722         .store = blk_throtl_sample_time_store,
 723 };
 724 #endif
 725
 726 static struct attribute *default_attrs[] = {
 727         &queue_requests_entry.attr,
 728         &queue_ra_entry.attr,
 729         &queue_max_hw_sectors_entry.attr,
 730         &queue_max_sectors_entry.attr,
 731         &queue_max_segments_entry.attr,
 732         &queue_max_discard_segments_entry.attr,
 733         &queue_max_integrity_segments_entry.attr,
 734         &queue_max_segment_size_entry.attr,
 735         &queue_iosched_entry.attr,
 736         &queue_hw_sector_size_entry.attr,
 737         &queue_logical_block_size_entry.attr,
 738         &queue_physical_block_size_entry.attr,
 739         &queue_chunk_sectors_entry.attr,
 740         &queue_io_min_entry.attr,
 741         &queue_io_opt_entry.attr,
 742         &queue_discard_granularity_entry.attr,
 743         &queue_discard_max_entry.attr,
 744         &queue_discard_max_hw_entry.attr,
 745         &queue_discard_zeroes_data_entry.attr,
 746         &queue_write_same_max_entry.attr,
 747         &queue_write_zeroes_max_entry.attr,
 748         &queue_nonrot_entry.attr,
 749         &queue_zoned_entry.attr,
 750         &queue_nr_zones_entry.attr,
 751         &queue_nomerges_entry.attr,
 752         &queue_rq_affinity_entry.attr,
 753         &queue_iostats_entry.attr,
 754         &queue_random_entry.attr,
 755         &queue_poll_entry.attr,
 756         &queue_wc_entry.attr,
 757         &queue_fua_entry.attr,
 758         &queue_dax_entry.attr,
 759         &queue_wb_lat_entry.attr,
 760         &queue_poll_delay_entry.attr,
 761         &queue_io_timeout_entry.attr,
 762 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 763         &throtl_sample_time_entry.attr,
 764 #endif
 765         NULL,
 766 };
 767
 768 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 769
 770 static ssize_t
 771 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 772 {
 773         struct queue_sysfs_entry *entry = to_queue(attr);
 774         struct request_queue *q =
 775                 container_of(kobj, struct request_queue, kobj);
 776         ssize_t res;
 777
 778         if (!entry->show)
 779                 return -EIO;
 780         mutex_lock(&q->sysfs_lock);
 781         if (blk_queue_dying(q)) {
 782                 mutex_unlock(&q->sysfs_lock);
 783                 return -ENOENT;
 784         }
 785         res = entry->show(q, page);
 786         mutex_unlock(&q->sysfs_lock);
 787         return res;
 788 }
 789
 790 static ssize_t
 791 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 792                     const char *page, size_t length)
 793 {
 794         struct queue_sysfs_entry *entry = to_queue(attr);
 795         struct request_queue *q;
 796         ssize_t res;
 797
 798         if (!entry->store)
 799                 return -EIO;
 800
 801         q = container_of(kobj, struct request_queue, kobj);
 802         mutex_lock(&q->sysfs_lock);
 803         if (blk_queue_dying(q)) {
 804                 mutex_unlock(&q->sysfs_lock);
 805                 return -ENOENT;
 806         }
 807         res = entry->store(q, page, length);
 808         mutex_unlock(&q->sysfs_lock);
 809         return res;
 810 }
 811
 812 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 813 {
 814         struct request_queue *q = container_of(rcu_head, struct request_queue,
 815                                                rcu_head);
 816         kmem_cache_free(blk_requestq_cachep, q);
 817 }
 818
 819 /**
 820  * __blk_release_queue - release a request queue when it is no longer needed
 821  * @work: pointer to the release_work member of the request queue to be released
 822  *
 823  * Description:
 824  *     blk_release_queue is the counterpart of blk_init_queue(). It should be
 825  *     called when a request queue is being released; typically when a block
 826  *     device is being de-registered. Its primary task it to free the queue
 827  *     itself.
 828  *
 829  * Notes:
 830  *     The low level driver must have finished any outstanding requests first
 831  *     via blk_cleanup_queue().
 832  *
 833  *     Although blk_release_queue() may be called with preemption disabled,
 834  *     __blk_release_queue() may sleep.
 835  */
 836 static void __blk_release_queue(struct work_struct *work)
 837 {
 838         struct request_queue *q = container_of(work, typeof(*q), release_work);
 839
 840         if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags))
 841                 blk_stat_remove_callback(q, q->poll_cb);
 842         blk_stat_free_callback(q->poll_cb);
 843
 844         if (!blk_queue_dead(q)) {
 845                 /*
 846                  * Last reference was dropped without having called
 847                  * blk_cleanup_queue().
 848                  */
 849                 WARN_ONCE(blk_queue_init_done(q),
 850                           "request queue %p has been registered but blk_cleanup_queue() has not been called for that queue\n",
 851                           q);
 852                 blk_exit_queue(q);
 853         }
 854
 855         WARN(blk_queue_root_blkg(q),
 856              "request queue %p is being released but it has not yet been removed from the blkcg controller\n",
 857              q);
 858
 859         blk_free_queue_stats(q->stats);
 860
 861         blk_queue_free_zone_bitmaps(q);
 862
 863         if (queue_is_mq(q))
 864                 blk_mq_release(q);
 865
 866         blk_trace_shutdown(q);
 867
 868         if (queue_is_mq(q))
 869                 blk_mq_debugfs_unregister(q);
 870
 871         bioset_exit(&q->bio_split);
 872
 873         ida_simple_remove(&blk_queue_ida, q->id);
 874         call_rcu(&q->rcu_head, blk_free_queue_rcu);
 875 }
 876
 877 static void blk_release_queue(struct kobject *kobj)
 878 {
 879         struct request_queue *q =
 880                 container_of(kobj, struct request_queue, kobj);
 881
 882         INIT_WORK(&q->release_work, __blk_release_queue);
 883         schedule_work(&q->release_work);
 884 }
 885
 886 static const struct sysfs_ops queue_sysfs_ops = {
 887         .show   = queue_attr_show,
 888         .store  = queue_attr_store,
 889 };
 890
 891 struct kobj_type blk_queue_ktype = {
 892         .sysfs_ops      = &queue_sysfs_ops,
 893         .default_attrs  = default_attrs,
 894         .release        = blk_release_queue,
 895 };
 896
 897 /**
 898  * blk_register_queue - register a block layer queue with sysfs
 899  * @disk: Disk of which the request queue should be registered with sysfs.
 900  */
 901 int blk_register_queue(struct gendisk *disk)
 902 {
 903         int ret;
 904         struct device *dev = disk_to_dev(disk);
 905         struct request_queue *q = disk->queue;
 906
 907         if (WARN_ON(!q))
 908                 return -ENXIO;
 909
 910         WARN_ONCE(test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags),
 911                   "%s is registering an already registered queue\n",
 912                   kobject_name(&dev->kobj));
 913         blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);
 914
 915         /*
 916          * SCSI probing may synchronously create and destroy a lot of
 917          * request_queues for non-existent devices.  Shutting down a fully
 918          * functional queue takes measureable wallclock time as RCU grace
 919          * periods are involved.  To avoid excessive latency in these
 920          * cases, a request_queue starts out in a degraded mode which is
 921          * faster to shut down and is made fully functional here as
 922          * request_queues for non-existent devices never get registered.
 923          */
 924         if (!blk_queue_init_done(q)) {
 925                 blk_queue_flag_set(QUEUE_FLAG_INIT_DONE, q);
 926                 percpu_ref_switch_to_percpu(&q->q_usage_counter);
 927         }
 928
 929         ret = blk_trace_init_sysfs(dev);
 930         if (ret)
 931                 return ret;
 932
 933         /* Prevent changes through sysfs until registration is completed. */
 934         mutex_lock(&q->sysfs_lock);
 935
 936         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 937         if (ret < 0) {
 938                 blk_trace_remove_sysfs(dev);
 939                 goto unlock;
 940         }
 941
 942         if (queue_is_mq(q)) {
 943                 __blk_mq_register_dev(dev, q);
 944                 blk_mq_debugfs_register(q);
 945         }
 946
 947         kobject_uevent(&q->kobj, KOBJ_ADD);
 948
 949         wbt_enable_default(q);
 950
 951         blk_throtl_register_queue(q);
 952
 953         if (q->elevator) {
 954                 ret = elv_register_queue(q);
 955                 if (ret) {
 956                         mutex_unlock(&q->sysfs_lock);
 957                         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 958                         kobject_del(&q->kobj);
 959                         blk_trace_remove_sysfs(dev);
 960                         kobject_put(&dev->kobj);
 961                         return ret;
 962                 }
 963         }
 964         ret = 0;
 965 unlock:
 966         mutex_unlock(&q->sysfs_lock);
 967         return ret;
 968 }
 969 EXPORT_SYMBOL_GPL(blk_register_queue);
 970
 971 /**
 972  * blk_unregister_queue - counterpart of blk_register_queue()
 973  * @disk: Disk of which the request queue should be unregistered from sysfs.
 974  *
 975  * Note: the caller is responsible for guaranteeing that this function is called
 976  * after blk_register_queue() has finished.
 977  */
 978 void blk_unregister_queue(struct gendisk *disk)
 979 {
 980         struct request_queue *q = disk->queue;
 981
 982         if (WARN_ON(!q))
 983                 return;
 984
 985         /* Return early if disk->queue was never registered. */
 986         if (!test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags))
 987                 return;
 988
 989         /*
 990          * Since sysfs_remove_dir() prevents adding new directory entries
 991          * before removal of existing entries starts, protect against
 992          * concurrent elv_iosched_store() calls.
 993          */
 994         mutex_lock(&q->sysfs_lock);
 995
 996         blk_queue_flag_clear(QUEUE_FLAG_REGISTERED, q);
 997
 998         /*
 999          * Remove the sysfs attributes before unregistering the queue data
1000          * structures that can be modified through sysfs.
1001          */
1002         if (queue_is_mq(q))
1003                 blk_mq_unregister_dev(disk_to_dev(disk), q);
1004         mutex_unlock(&q->sysfs_lock);
1005
1006         kobject_uevent(&q->kobj, KOBJ_REMOVE);
1007         kobject_del(&q->kobj);
1008         blk_trace_remove_sysfs(disk_to_dev(disk));
1009
1010         mutex_lock(&q->sysfs_lock);
1011         if (q->elevator)
1012                 elv_unregister_queue(q);
1013         mutex_unlock(&q->sysfs_lock);
1014
1015         kobject_put(&disk_to_dev(disk)->kobj);
1016 }