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