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 == BLK_MQ_POLL_CLASSIC)
 364                 val = BLK_MQ_POLL_CLASSIC;
 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 == BLK_MQ_POLL_CLASSIC)
 384                 q->poll_nsec = BLK_MQ_POLL_CLASSIC;
 385         else if (val >= 0)
 386                 q->poll_nsec = val * 1000;
 387         else
 388                 return -EINVAL;
 389
 390         return count;
 391 }
 392
 393 static ssize_t queue_poll_show(struct request_queue *q, char *page)
 394 {
 395         return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
 396 }
 397
 398 static ssize_t queue_poll_store(struct request_queue *q, const char *page,
 399                                 size_t count)
 400 {
 401         unsigned long poll_on;
 402         ssize_t ret;
 403
 404         if (!q->tag_set || q->tag_set->nr_maps <= HCTX_TYPE_POLL ||
 405             !q->tag_set->map[HCTX_TYPE_POLL].nr_queues)
 406                 return -EINVAL;
 407
 408         ret = queue_var_store(&poll_on, page, count);
 409         if (ret < 0)
 410                 return ret;
 411
 412         if (poll_on)
 413                 blk_queue_flag_set(QUEUE_FLAG_POLL, q);
 414         else
 415                 blk_queue_flag_clear(QUEUE_FLAG_POLL, q);
 416
 417         return ret;
 418 }
 419
 420 static ssize_t queue_io_timeout_show(struct request_queue *q, char *page)
 421 {
 422         return sprintf(page, "%u\n", jiffies_to_msecs(q->rq_timeout));
 423 }
 424
 425 static ssize_t queue_io_timeout_store(struct request_queue *q, const char *page,
 426                                   size_t count)
 427 {
 428         unsigned int val;
 429         int err;
 430
 431         err = kstrtou32(page, 10, &val);
 432         if (err || val == 0)
 433                 return -EINVAL;
 434
 435         blk_queue_rq_timeout(q, msecs_to_jiffies(val));
 436
 437         return count;
 438 }
 439
 440 static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
 441 {
 442         if (!wbt_rq_qos(q))
 443                 return -EINVAL;
 444
 445         return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));
 446 }
 447
 448 static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
 449                                   size_t count)
 450 {
 451         struct rq_qos *rqos;
 452         ssize_t ret;
 453         s64 val;
 454
 455         ret = queue_var_store64(&val, page);
 456         if (ret < 0)
 457                 return ret;
 458         if (val < -1)
 459                 return -EINVAL;
 460
 461         rqos = wbt_rq_qos(q);
 462         if (!rqos) {
 463                 ret = wbt_init(q);
 464                 if (ret)
 465                         return ret;
 466         }
 467
 468         if (val == -1)
 469                 val = wbt_default_latency_nsec(q);
 470         else if (val >= 0)
 471                 val *= 1000ULL;
 472
 473         if (wbt_get_min_lat(q) == val)
 474                 return count;
 475
 476         /*
 477          * Ensure that the queue is idled, in case the latency update
 478          * ends up either enabling or disabling wbt completely. We can't
 479          * have IO inflight if that happens.
 480          */
 481         blk_mq_freeze_queue(q);
 482         blk_mq_quiesce_queue(q);
 483
 484         wbt_set_min_lat(q, val);
 485         wbt_update_limits(q);
 486
 487         blk_mq_unquiesce_queue(q);
 488         blk_mq_unfreeze_queue(q);
 489
 490         return count;
 491 }
 492
 493 static ssize_t queue_wc_show(struct request_queue *q, char *page)
 494 {
 495         if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
 496                 return sprintf(page, "write back\n");
 497
 498         return sprintf(page, "write through\n");
 499 }
 500
 501 static ssize_t queue_wc_store(struct request_queue *q, const char *page,
 502                               size_t count)
 503 {
 504         int set = -1;
 505
 506         if (!strncmp(page, "write back", 10))
 507                 set = 1;
 508         else if (!strncmp(page, "write through", 13) ||
 509                  !strncmp(page, "none", 4))
 510                 set = 0;
 511
 512         if (set == -1)
 513                 return -EINVAL;
 514
 515         if (set)
 516                 blk_queue_flag_set(QUEUE_FLAG_WC, q);
 517         else
 518                 blk_queue_flag_clear(QUEUE_FLAG_WC, q);
 519
 520         return count;
 521 }
 522
 523 static ssize_t queue_fua_show(struct request_queue *q, char *page)
 524 {
 525         return sprintf(page, "%u\n", test_bit(QUEUE_FLAG_FUA, &q->queue_flags));
 526 }
 527
 528 static ssize_t queue_dax_show(struct request_queue *q, char *page)
 529 {
 530         return queue_var_show(blk_queue_dax(q), page);
 531 }
 532
 533 static struct queue_sysfs_entry queue_requests_entry = {
 534         .attr = {.name = "nr_requests", .mode = 0644 },
 535         .show = queue_requests_show,
 536         .store = queue_requests_store,
 537 };
 538
 539 static struct queue_sysfs_entry queue_ra_entry = {
 540         .attr = {.name = "read_ahead_kb", .mode = 0644 },
 541         .show = queue_ra_show,
 542         .store = queue_ra_store,
 543 };
 544
 545 static struct queue_sysfs_entry queue_max_sectors_entry = {
 546         .attr = {.name = "max_sectors_kb", .mode = 0644 },
 547         .show = queue_max_sectors_show,
 548         .store = queue_max_sectors_store,
 549 };
 550
 551 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 552         .attr = {.name = "max_hw_sectors_kb", .mode = 0444 },
 553         .show = queue_max_hw_sectors_show,
 554 };
 555
 556 static struct queue_sysfs_entry queue_max_segments_entry = {
 557         .attr = {.name = "max_segments", .mode = 0444 },
 558         .show = queue_max_segments_show,
 559 };
 560
 561 static struct queue_sysfs_entry queue_max_discard_segments_entry = {
 562         .attr = {.name = "max_discard_segments", .mode = 0444 },
 563         .show = queue_max_discard_segments_show,
 564 };
 565
 566 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
 567         .attr = {.name = "max_integrity_segments", .mode = 0444 },
 568         .show = queue_max_integrity_segments_show,
 569 };
 570
 571 static struct queue_sysfs_entry queue_max_segment_size_entry = {
 572         .attr = {.name = "max_segment_size", .mode = 0444 },
 573         .show = queue_max_segment_size_show,
 574 };
 575
 576 static struct queue_sysfs_entry queue_iosched_entry = {
 577         .attr = {.name = "scheduler", .mode = 0644 },
 578         .show = elv_iosched_show,
 579         .store = elv_iosched_store,
 580 };
 581
 582 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 583         .attr = {.name = "hw_sector_size", .mode = 0444 },
 584         .show = queue_logical_block_size_show,
 585 };
 586
 587 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 588         .attr = {.name = "logical_block_size", .mode = 0444 },
 589         .show = queue_logical_block_size_show,
 590 };
 591
 592 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 593         .attr = {.name = "physical_block_size", .mode = 0444 },
 594         .show = queue_physical_block_size_show,
 595 };
 596
 597 static struct queue_sysfs_entry queue_chunk_sectors_entry = {
 598         .attr = {.name = "chunk_sectors", .mode = 0444 },
 599         .show = queue_chunk_sectors_show,
 600 };
 601
 602 static struct queue_sysfs_entry queue_io_min_entry = {
 603         .attr = {.name = "minimum_io_size", .mode = 0444 },
 604         .show = queue_io_min_show,
 605 };
 606
 607 static struct queue_sysfs_entry queue_io_opt_entry = {
 608         .attr = {.name = "optimal_io_size", .mode = 0444 },
 609         .show = queue_io_opt_show,
 610 };
 611
 612 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 613         .attr = {.name = "discard_granularity", .mode = 0444 },
 614         .show = queue_discard_granularity_show,
 615 };
 616
 617 static struct queue_sysfs_entry queue_discard_max_hw_entry = {
 618         .attr = {.name = "discard_max_hw_bytes", .mode = 0444 },
 619         .show = queue_discard_max_hw_show,
 620 };
 621
 622 static struct queue_sysfs_entry queue_discard_max_entry = {
 623         .attr = {.name = "discard_max_bytes", .mode = 0644 },
 624         .show = queue_discard_max_show,
 625         .store = queue_discard_max_store,
 626 };
 627
 628 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 629         .attr = {.name = "discard_zeroes_data", .mode = 0444 },
 630         .show = queue_discard_zeroes_data_show,
 631 };
 632
 633 static struct queue_sysfs_entry queue_write_same_max_entry = {
 634         .attr = {.name = "write_same_max_bytes", .mode = 0444 },
 635         .show = queue_write_same_max_show,
 636 };
 637
 638 static struct queue_sysfs_entry queue_write_zeroes_max_entry = {
 639         .attr = {.name = "write_zeroes_max_bytes", .mode = 0444 },
 640         .show = queue_write_zeroes_max_show,
 641 };
 642
 643 static struct queue_sysfs_entry queue_nonrot_entry = {
 644         .attr = {.name = "rotational", .mode = 0644 },
 645         .show = queue_show_nonrot,
 646         .store = queue_store_nonrot,
 647 };
 648
 649 static struct queue_sysfs_entry queue_zoned_entry = {
 650         .attr = {.name = "zoned", .mode = 0444 },
 651         .show = queue_zoned_show,
 652 };
 653
 654 static struct queue_sysfs_entry queue_nr_zones_entry = {
 655         .attr = {.name = "nr_zones", .mode = 0444 },
 656         .show = queue_nr_zones_show,
 657 };
 658
 659 static struct queue_sysfs_entry queue_nomerges_entry = {
 660         .attr = {.name = "nomerges", .mode = 0644 },
 661         .show = queue_nomerges_show,
 662         .store = queue_nomerges_store,
 663 };
 664
 665 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 666         .attr = {.name = "rq_affinity", .mode = 0644 },
 667         .show = queue_rq_affinity_show,
 668         .store = queue_rq_affinity_store,
 669 };
 670
 671 static struct queue_sysfs_entry queue_iostats_entry = {
 672         .attr = {.name = "iostats", .mode = 0644 },
 673         .show = queue_show_iostats,
 674         .store = queue_store_iostats,
 675 };
 676
 677 static struct queue_sysfs_entry queue_random_entry = {
 678         .attr = {.name = "add_random", .mode = 0644 },
 679         .show = queue_show_random,
 680         .store = queue_store_random,
 681 };
 682
 683 static struct queue_sysfs_entry queue_poll_entry = {
 684         .attr = {.name = "io_poll", .mode = 0644 },
 685         .show = queue_poll_show,
 686         .store = queue_poll_store,
 687 };
 688
 689 static struct queue_sysfs_entry queue_poll_delay_entry = {
 690         .attr = {.name = "io_poll_delay", .mode = 0644 },
 691         .show = queue_poll_delay_show,
 692         .store = queue_poll_delay_store,
 693 };
 694
 695 static struct queue_sysfs_entry queue_wc_entry = {
 696         .attr = {.name = "write_cache", .mode = 0644 },
 697         .show = queue_wc_show,
 698         .store = queue_wc_store,
 699 };
 700
 701 static struct queue_sysfs_entry queue_fua_entry = {
 702         .attr = {.name = "fua", .mode = 0444 },
 703         .show = queue_fua_show,
 704 };
 705
 706 static struct queue_sysfs_entry queue_dax_entry = {
 707         .attr = {.name = "dax", .mode = 0444 },
 708         .show = queue_dax_show,
 709 };
 710
 711 static struct queue_sysfs_entry queue_io_timeout_entry = {
 712         .attr = {.name = "io_timeout", .mode = 0644 },
 713         .show = queue_io_timeout_show,
 714         .store = queue_io_timeout_store,
 715 };
 716
 717 static struct queue_sysfs_entry queue_wb_lat_entry = {
 718         .attr = {.name = "wbt_lat_usec", .mode = 0644 },
 719         .show = queue_wb_lat_show,
 720         .store = queue_wb_lat_store,
 721 };
 722
 723 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 724 static struct queue_sysfs_entry throtl_sample_time_entry = {
 725         .attr = {.name = "throttle_sample_time", .mode = 0644 },
 726         .show = blk_throtl_sample_time_show,
 727         .store = blk_throtl_sample_time_store,
 728 };
 729 #endif
 730
 731 static struct attribute *queue_attrs[] = {
 732         &queue_requests_entry.attr,
 733         &queue_ra_entry.attr,
 734         &queue_max_hw_sectors_entry.attr,
 735         &queue_max_sectors_entry.attr,
 736         &queue_max_segments_entry.attr,
 737         &queue_max_discard_segments_entry.attr,
 738         &queue_max_integrity_segments_entry.attr,
 739         &queue_max_segment_size_entry.attr,
 740         &queue_iosched_entry.attr,
 741         &queue_hw_sector_size_entry.attr,
 742         &queue_logical_block_size_entry.attr,
 743         &queue_physical_block_size_entry.attr,
 744         &queue_chunk_sectors_entry.attr,
 745         &queue_io_min_entry.attr,
 746         &queue_io_opt_entry.attr,
 747         &queue_discard_granularity_entry.attr,
 748         &queue_discard_max_entry.attr,
 749         &queue_discard_max_hw_entry.attr,
 750         &queue_discard_zeroes_data_entry.attr,
 751         &queue_write_same_max_entry.attr,
 752         &queue_write_zeroes_max_entry.attr,
 753         &queue_nonrot_entry.attr,
 754         &queue_zoned_entry.attr,
 755         &queue_nr_zones_entry.attr,
 756         &queue_nomerges_entry.attr,
 757         &queue_rq_affinity_entry.attr,
 758         &queue_iostats_entry.attr,
 759         &queue_random_entry.attr,
 760         &queue_poll_entry.attr,
 761         &queue_wc_entry.attr,
 762         &queue_fua_entry.attr,
 763         &queue_dax_entry.attr,
 764         &queue_wb_lat_entry.attr,
 765         &queue_poll_delay_entry.attr,
 766         &queue_io_timeout_entry.attr,
 767 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 768         &throtl_sample_time_entry.attr,
 769 #endif
 770         NULL,
 771 };
 772
 773 static umode_t queue_attr_visible(struct kobject *kobj, struct attribute *attr,
 774                                 int n)
 775 {
 776         struct request_queue *q =
 777                 container_of(kobj, struct request_queue, kobj);
 778
 779         if (attr == &queue_io_timeout_entry.attr &&
 780                 (!q->mq_ops || !q->mq_ops->timeout))
 781                         return 0;
 782
 783         return attr->mode;
 784 }
 785
 786 static struct attribute_group queue_attr_group = {
 787         .attrs = queue_attrs,
 788         .is_visible = queue_attr_visible,
 789 };
 790
 791
 792 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 793
 794 static ssize_t
 795 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 796 {
 797         struct queue_sysfs_entry *entry = to_queue(attr);
 798         struct request_queue *q =
 799                 container_of(kobj, struct request_queue, kobj);
 800         ssize_t res;
 801
 802         if (!entry->show)
 803                 return -EIO;
 804         mutex_lock(&q->sysfs_lock);
 805         if (blk_queue_dying(q)) {
 806                 mutex_unlock(&q->sysfs_lock);
 807                 return -ENOENT;
 808         }
 809         res = entry->show(q, page);
 810         mutex_unlock(&q->sysfs_lock);
 811         return res;
 812 }
 813
 814 static ssize_t
 815 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 816                     const char *page, size_t length)
 817 {
 818         struct queue_sysfs_entry *entry = to_queue(attr);
 819         struct request_queue *q;
 820         ssize_t res;
 821
 822         if (!entry->store)
 823                 return -EIO;
 824
 825         q = container_of(kobj, struct request_queue, kobj);
 826         mutex_lock(&q->sysfs_lock);
 827         if (blk_queue_dying(q)) {
 828                 mutex_unlock(&q->sysfs_lock);
 829                 return -ENOENT;
 830         }
 831         res = entry->store(q, page, length);
 832         mutex_unlock(&q->sysfs_lock);
 833         return res;
 834 }
 835
 836 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 837 {
 838         struct request_queue *q = container_of(rcu_head, struct request_queue,
 839                                                rcu_head);
 840         kmem_cache_free(blk_requestq_cachep, q);
 841 }
 842
 843 /* Unconfigure the I/O scheduler and dissociate from the cgroup controller. */
 844 static void blk_exit_queue(struct request_queue *q)
 845 {
 846         /*
 847          * Since the I/O scheduler exit code may access cgroup information,
 848          * perform I/O scheduler exit before disassociating from the block
 849          * cgroup controller.
 850          */
 851         if (q->elevator) {
 852                 ioc_clear_queue(q);
 853                 __elevator_exit(q, q->elevator);
 854                 q->elevator = NULL;
 855         }
 856
 857         /*
 858          * Remove all references to @q from the block cgroup controller before
 859          * restoring @q->queue_lock to avoid that restoring this pointer causes
 860          * e.g. blkcg_print_blkgs() to crash.
 861          */
 862         blkcg_exit_queue(q);
 863
 864         /*
 865          * Since the cgroup code may dereference the @q->backing_dev_info
 866          * pointer, only decrease its reference count after having removed the
 867          * association with the block cgroup controller.
 868          */
 869         bdi_put(q->backing_dev_info);
 870 }
 871
 872
 873 /**
 874  * __blk_release_queue - release a request queue
 875  * @work: pointer to the release_work member of the request queue to be released
 876  *
 877  * Description:
 878  *     This function is called when a block device is being unregistered. The
 879  *     process of releasing a request queue starts with blk_cleanup_queue, which
 880  *     set the appropriate flags and then calls blk_put_queue, that decrements
 881  *     the reference counter of the request queue. Once the reference counter
 882  *     of the request queue reaches zero, blk_release_queue is called to release
 883  *     all allocated resources of the request queue.
 884  */
 885 static void __blk_release_queue(struct work_struct *work)
 886 {
 887         struct request_queue *q = container_of(work, typeof(*q), release_work);
 888
 889         if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags))
 890                 blk_stat_remove_callback(q, q->poll_cb);
 891         blk_stat_free_callback(q->poll_cb);
 892
 893         blk_free_queue_stats(q->stats);
 894
 895         if (queue_is_mq(q))
 896                 cancel_delayed_work_sync(&q->requeue_work);
 897
 898         blk_exit_queue(q);
 899
 900         blk_queue_free_zone_bitmaps(q);
 901
 902         if (queue_is_mq(q))
 903                 blk_mq_release(q);
 904
 905         blk_trace_shutdown(q);
 906
 907         if (queue_is_mq(q))
 908                 blk_mq_debugfs_unregister(q);
 909
 910         bioset_exit(&q->bio_split);
 911
 912         ida_simple_remove(&blk_queue_ida, q->id);
 913         call_rcu(&q->rcu_head, blk_free_queue_rcu);
 914 }
 915
 916 static void blk_release_queue(struct kobject *kobj)
 917 {
 918         struct request_queue *q =
 919                 container_of(kobj, struct request_queue, kobj);
 920
 921         INIT_WORK(&q->release_work, __blk_release_queue);
 922         schedule_work(&q->release_work);
 923 }
 924
 925 static const struct sysfs_ops queue_sysfs_ops = {
 926         .show   = queue_attr_show,
 927         .store  = queue_attr_store,
 928 };
 929
 930 struct kobj_type blk_queue_ktype = {
 931         .sysfs_ops      = &queue_sysfs_ops,
 932         .release        = blk_release_queue,
 933 };
 934
 935 /**
 936  * blk_register_queue - register a block layer queue with sysfs
 937  * @disk: Disk of which the request queue should be registered with sysfs.
 938  */
 939 int blk_register_queue(struct gendisk *disk)
 940 {
 941         int ret;
 942         struct device *dev = disk_to_dev(disk);
 943         struct request_queue *q = disk->queue;
 944         bool has_elevator = false;
 945
 946         if (WARN_ON(!q))
 947                 return -ENXIO;
 948
 949         WARN_ONCE(blk_queue_registered(q),
 950                   "%s is registering an already registered queue\n",
 951                   kobject_name(&dev->kobj));
 952
 953         /*
 954          * SCSI probing may synchronously create and destroy a lot of
 955          * request_queues for non-existent devices.  Shutting down a fully
 956          * functional queue takes measureable wallclock time as RCU grace
 957          * periods are involved.  To avoid excessive latency in these
 958          * cases, a request_queue starts out in a degraded mode which is
 959          * faster to shut down and is made fully functional here as
 960          * request_queues for non-existent devices never get registered.
 961          */
 962         if (!blk_queue_init_done(q)) {
 963                 blk_queue_flag_set(QUEUE_FLAG_INIT_DONE, q);
 964                 percpu_ref_switch_to_percpu(&q->q_usage_counter);
 965         }
 966
 967         ret = blk_trace_init_sysfs(dev);
 968         if (ret)
 969                 return ret;
 970
 971         mutex_lock(&q->sysfs_dir_lock);
 972
 973         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 974         if (ret < 0) {
 975                 blk_trace_remove_sysfs(dev);
 976                 goto unlock;
 977         }
 978
 979         ret = sysfs_create_group(&q->kobj, &queue_attr_group);
 980         if (ret) {
 981                 blk_trace_remove_sysfs(dev);
 982                 kobject_del(&q->kobj);
 983                 kobject_put(&dev->kobj);
 984                 goto unlock;
 985         }
 986
 987         if (queue_is_mq(q)) {
 988                 __blk_mq_register_dev(dev, q);
 989                 blk_mq_debugfs_register(q);
 990         }
 991
 992         /*
 993          * The flag of QUEUE_FLAG_REGISTERED isn't set yet, so elevator
 994          * switch won't happen at all.
 995          */
 996         if (q->elevator) {
 997                 ret = elv_register_queue(q, false);
 998                 if (ret) {
 999                         mutex_unlock(&q->sysfs_dir_lock);
1000                         kobject_del(&q->kobj);
1001                         blk_trace_remove_sysfs(dev);
1002                         kobject_put(&dev->kobj);
1003                         return ret;
1004                 }
1005                 has_elevator = true;
1006         }
1007
1008         mutex_lock(&q->sysfs_lock);
1009         blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);
1010         wbt_enable_default(q);
1011         blk_throtl_register_queue(q);
1012
1013         /* Now everything is ready and send out KOBJ_ADD uevent */
1014         kobject_uevent(&q->kobj, KOBJ_ADD);
1015         if (has_elevator)
1016                 kobject_uevent(&q->elevator->kobj, KOBJ_ADD);
1017         mutex_unlock(&q->sysfs_lock);
1018
1019         ret = 0;
1020 unlock:
1021         mutex_unlock(&q->sysfs_dir_lock);
1022         return ret;
1023 }
1024 EXPORT_SYMBOL_GPL(blk_register_queue);
1025
1026 /**
1027  * blk_unregister_queue - counterpart of blk_register_queue()
1028  * @disk: Disk of which the request queue should be unregistered from sysfs.
1029  *
1030  * Note: the caller is responsible for guaranteeing that this function is called
1031  * after blk_register_queue() has finished.
1032  */
1033 void blk_unregister_queue(struct gendisk *disk)
1034 {
1035         struct request_queue *q = disk->queue;
1036
1037         if (WARN_ON(!q))
1038                 return;
1039
1040         /* Return early if disk->queue was never registered. */
1041         if (!blk_queue_registered(q))
1042                 return;
1043
1044         /*
1045          * Since sysfs_remove_dir() prevents adding new directory entries
1046          * before removal of existing entries starts, protect against
1047          * concurrent elv_iosched_store() calls.
1048          */
1049         mutex_lock(&q->sysfs_lock);
1050         blk_queue_flag_clear(QUEUE_FLAG_REGISTERED, q);
1051         mutex_unlock(&q->sysfs_lock);
1052
1053         mutex_lock(&q->sysfs_dir_lock);
1054         /*
1055          * Remove the sysfs attributes before unregistering the queue data
1056          * structures that can be modified through sysfs.
1057          */
1058         if (queue_is_mq(q))
1059                 blk_mq_unregister_dev(disk_to_dev(disk), q);
1060
1061         kobject_uevent(&q->kobj, KOBJ_REMOVE);
1062         kobject_del(&q->kobj);
1063         blk_trace_remove_sysfs(disk_to_dev(disk));
1064
1065         /*
1066          * q->kobj has been removed, so it is safe to check if elevator
1067          * exists without holding q->sysfs_lock.
1068          */
1069         if (q->elevator)
1070                 elv_unregister_queue(q);
1071         mutex_unlock(&q->sysfs_dir_lock);
1072
1073         kobject_put(&disk_to_dev(disk)->kobj);
1074 }