block/blk-sysfs.c

   1 /*
   2  * Functions related to sysfs handling
   3  */
   4 #include <linux/kernel.h>
   5 #include <linux/slab.h>
   6 #include <linux/module.h>
   7 #include <linux/bio.h>
   8 #include <linux/blkdev.h>
   9 #include <linux/backing-dev.h>
  10 #include <linux/blktrace_api.h>
  11 #include <linux/blk-mq.h>
  12 #include <linux/blk-cgroup.h>
  13
  14 #include "blk.h"
  15 #include "blk-mq.h"
  16 #include "blk-wbt.h"
  17
  18 struct queue_sysfs_entry {
  19         struct attribute attr;
  20         ssize_t (*show)(struct request_queue *, char *);
  21         ssize_t (*store)(struct request_queue *, const char *, size_t);
  22 };
  23
  24 static ssize_t
  25 queue_var_show(unsigned long var, char *page)
  26 {
  27         return sprintf(page, "%lu\n", var);
  28 }
  29
  30 static ssize_t
  31 queue_var_store(unsigned long *var, const char *page, size_t count)
  32 {
  33         int err;
  34         unsigned long v;
  35
  36         err = kstrtoul(page, 10, &v);
  37         if (err || v > UINT_MAX)
  38                 return -EINVAL;
  39
  40         *var = v;
  41
  42         return count;
  43 }
  44
  45 static ssize_t queue_var_store64(s64 *var, const char *page)
  46 {
  47         int err;
  48         s64 v;
  49
  50         err = kstrtos64(page, 10, &v);
  51         if (err < 0)
  52                 return err;
  53
  54         *var = v;
  55         return 0;
  56 }
  57
  58 static ssize_t queue_requests_show(struct request_queue *q, char *page)
  59 {
  60         return queue_var_show(q->nr_requests, (page));
  61 }
  62
  63 static ssize_t
  64 queue_requests_store(struct request_queue *q, const char *page, size_t count)
  65 {
  66         unsigned long nr;
  67         int ret, err;
  68
  69         if (!q->request_fn && !q->mq_ops)
  70                 return -EINVAL;
  71
  72         ret = queue_var_store(&nr, page, count);
  73         if (ret < 0)
  74                 return ret;
  75
  76         if (nr < BLKDEV_MIN_RQ)
  77                 nr = BLKDEV_MIN_RQ;
  78
  79         if (q->request_fn)
  80                 err = blk_update_nr_requests(q, nr);
  81         else
  82                 err = blk_mq_update_nr_requests(q, nr);
  83
  84         if (err)
  85                 return err;
  86
  87         return ret;
  88 }
  89
  90 static ssize_t queue_ra_show(struct request_queue *q, char *page)
  91 {
  92         unsigned long ra_kb = q->backing_dev_info.ra_pages <<
  93                                         (PAGE_SHIFT - 10);
  94
  95         return queue_var_show(ra_kb, (page));
  96 }
  97
  98 static ssize_t
  99 queue_ra_store(struct request_queue *q, const char *page, size_t count)
 100 {
 101         unsigned long ra_kb;
 102         ssize_t ret = queue_var_store(&ra_kb, page, count);
 103
 104         if (ret < 0)
 105                 return ret;
 106
 107         q->backing_dev_info.ra_pages = ra_kb >> (PAGE_SHIFT - 10);
 108
 109         return ret;
 110 }
 111
 112 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
 113 {
 114         int max_sectors_kb = queue_max_sectors(q) >> 1;
 115
 116         return queue_var_show(max_sectors_kb, (page));
 117 }
 118
 119 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
 120 {
 121         return queue_var_show(queue_max_segments(q), (page));
 122 }
 123
 124 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
 125 {
 126         return queue_var_show(q->limits.max_integrity_segments, (page));
 127 }
 128
 129 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 130 {
 131         if (blk_queue_cluster(q))
 132                 return queue_var_show(queue_max_segment_size(q), (page));
 133
 134         return queue_var_show(PAGE_SIZE, (page));
 135 }
 136
 137 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 138 {
 139         return queue_var_show(queue_logical_block_size(q), page);
 140 }
 141
 142 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 143 {
 144         return queue_var_show(queue_physical_block_size(q), page);
 145 }
 146
 147 static ssize_t queue_chunk_sectors_show(struct request_queue *q, char *page)
 148 {
 149         return queue_var_show(q->limits.chunk_sectors, page);
 150 }
 151
 152 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 153 {
 154         return queue_var_show(queue_io_min(q), page);
 155 }
 156
 157 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 158 {
 159         return queue_var_show(queue_io_opt(q), page);
 160 }
 161
 162 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 163 {
 164         return queue_var_show(q->limits.discard_granularity, page);
 165 }
 166
 167 static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
 168 {
 169
 170         return sprintf(page, "%llu\n",
 171                 (unsigned long long)q->limits.max_hw_discard_sectors << 9);
 172 }
 173
 174 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 175 {
 176         return sprintf(page, "%llu\n",
 177                        (unsigned long long)q->limits.max_discard_sectors << 9);
 178 }
 179
 180 static ssize_t queue_discard_max_store(struct request_queue *q,
 181                                        const char *page, size_t count)
 182 {
 183         unsigned long max_discard;
 184         ssize_t ret = queue_var_store(&max_discard, page, count);
 185
 186         if (ret < 0)
 187                 return ret;
 188
 189         if (max_discard & (q->limits.discard_granularity - 1))
 190                 return -EINVAL;
 191
 192         max_discard >>= 9;
 193         if (max_discard > UINT_MAX)
 194                 return -EINVAL;
 195
 196         if (max_discard > q->limits.max_hw_discard_sectors)
 197                 max_discard = q->limits.max_hw_discard_sectors;
 198
 199         q->limits.max_discard_sectors = max_discard;
 200         return ret;
 201 }
 202
 203 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 204 {
 205         return queue_var_show(queue_discard_zeroes_data(q), page);
 206 }
 207
 208 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
 209 {
 210         return sprintf(page, "%llu\n",
 211                 (unsigned long long)q->limits.max_write_same_sectors << 9);
 212 }
 213
 214 static ssize_t queue_write_zeroes_max_show(struct request_queue *q, char *page)
 215 {
 216         return sprintf(page, "%llu\n",
 217                 (unsigned long long)q->limits.max_write_zeroes_sectors << 9);
 218 }
 219
 220 static ssize_t
 221 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 222 {
 223         unsigned long max_sectors_kb,
 224                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 225                         page_kb = 1 << (PAGE_SHIFT - 10);
 226         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 227
 228         if (ret < 0)
 229                 return ret;
 230
 231         max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, (unsigned long)
 232                                          q->limits.max_dev_sectors >> 1);
 233
 234         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 235                 return -EINVAL;
 236
 237         spin_lock_irq(q->queue_lock);
 238         q->limits.max_sectors = max_sectors_kb << 1;
 239         q->backing_dev_info.io_pages = max_sectors_kb >> (PAGE_SHIFT - 10);
 240         spin_unlock_irq(q->queue_lock);
 241
 242         return ret;
 243 }
 244
 245 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 246 {
 247         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 248
 249         return queue_var_show(max_hw_sectors_kb, (page));
 250 }
 251
 252 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 253 static ssize_t                                                          \
 254 queue_show_##name(struct request_queue *q, char *page)                  \
 255 {                                                                       \
 256         int bit;                                                        \
 257         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 258         return queue_var_show(neg ? !bit : bit, page);                  \
 259 }                                                                       \
 260 static ssize_t                                                          \
 261 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
 262 {                                                                       \
 263         unsigned long val;                                              \
 264         ssize_t ret;                                                    \
 265         ret = queue_var_store(&val, page, count);                       \
 266         if (ret < 0)                                                    \
 267                  return ret;                                            \
 268         if (neg)                                                        \
 269                 val = !val;                                             \
 270                                                                         \
 271         spin_lock_irq(q->queue_lock);                                   \
 272         if (val)                                                        \
 273                 queue_flag_set(QUEUE_FLAG_##flag, q);                   \
 274         else                                                            \
 275                 queue_flag_clear(QUEUE_FLAG_##flag, q);                 \
 276         spin_unlock_irq(q->queue_lock);                                 \
 277         return ret;                                                     \
 278 }
 279
 280 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 281 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 282 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 283 #undef QUEUE_SYSFS_BIT_FNS
 284
 285 static ssize_t queue_zoned_show(struct request_queue *q, char *page)
 286 {
 287         switch (blk_queue_zoned_model(q)) {
 288         case BLK_ZONED_HA:
 289                 return sprintf(page, "host-aware\n");
 290         case BLK_ZONED_HM:
 291                 return sprintf(page, "host-managed\n");
 292         default:
 293                 return sprintf(page, "none\n");
 294         }
 295 }
 296
 297 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 298 {
 299         return queue_var_show((blk_queue_nomerges(q) << 1) |
 300                                blk_queue_noxmerges(q), page);
 301 }
 302
 303 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 304                                     size_t count)
 305 {
 306         unsigned long nm;
 307         ssize_t ret = queue_var_store(&nm, page, count);
 308
 309         if (ret < 0)
 310                 return ret;
 311
 312         spin_lock_irq(q->queue_lock);
 313         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 314         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 315         if (nm == 2)
 316                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 317         else if (nm)
 318                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 319         spin_unlock_irq(q->queue_lock);
 320
 321         return ret;
 322 }
 323
 324 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 325 {
 326         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 327         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 328
 329         return queue_var_show(set << force, page);
 330 }
 331
 332 static ssize_t
 333 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 334 {
 335         ssize_t ret = -EINVAL;
 336 #ifdef CONFIG_SMP
 337         unsigned long val;
 338
 339         ret = queue_var_store(&val, page, count);
 340         if (ret < 0)
 341                 return ret;
 342
 343         spin_lock_irq(q->queue_lock);
 344         if (val == 2) {
 345                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 346                 queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 347         } else if (val == 1) {
 348                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 349                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 350         } else if (val == 0) {
 351                 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 352                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 353         }
 354         spin_unlock_irq(q->queue_lock);
 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->mq_ops || !q->mq_ops->poll)
 403                 return -EINVAL;
 404
 405         ret = queue_var_store(&poll_on, page, count);
 406         if (ret < 0)
 407                 return ret;
 408
 409         spin_lock_irq(q->queue_lock);
 410         if (poll_on)
 411                 queue_flag_set(QUEUE_FLAG_POLL, q);
 412         else
 413                 queue_flag_clear(QUEUE_FLAG_POLL, q);
 414         spin_unlock_irq(q->queue_lock);
 415
 416         return ret;
 417 }
 418
 419 static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
 420 {
 421         if (!q->rq_wb)
 422                 return -EINVAL;
 423
 424         return sprintf(page, "%llu\n", div_u64(q->rq_wb->min_lat_nsec, 1000));
 425 }
 426
 427 static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
 428                                   size_t count)
 429 {
 430         struct rq_wb *rwb;
 431         ssize_t ret;
 432         s64 val;
 433
 434         ret = queue_var_store64(&val, page);
 435         if (ret < 0)
 436                 return ret;
 437         if (val < -1)
 438                 return -EINVAL;
 439
 440         rwb = q->rq_wb;
 441         if (!rwb) {
 442                 ret = wbt_init(q);
 443                 if (ret)
 444                         return ret;
 445
 446                 rwb = q->rq_wb;
 447                 if (!rwb)
 448                         return -EINVAL;
 449         }
 450
 451         if (val == -1)
 452                 rwb->min_lat_nsec = wbt_default_latency_nsec(q);
 453         else if (val >= 0)
 454                 rwb->min_lat_nsec = val * 1000ULL;
 455
 456         if (rwb->enable_state == WBT_STATE_ON_DEFAULT)
 457                 rwb->enable_state = WBT_STATE_ON_MANUAL;
 458
 459         wbt_update_limits(rwb);
 460         return count;
 461 }
 462
 463 static ssize_t queue_wc_show(struct request_queue *q, char *page)
 464 {
 465         if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
 466                 return sprintf(page, "write back\n");
 467
 468         return sprintf(page, "write through\n");
 469 }
 470
 471 static ssize_t queue_wc_store(struct request_queue *q, const char *page,
 472                               size_t count)
 473 {
 474         int set = -1;
 475
 476         if (!strncmp(page, "write back", 10))
 477                 set = 1;
 478         else if (!strncmp(page, "write through", 13) ||
 479                  !strncmp(page, "none", 4))
 480                 set = 0;
 481
 482         if (set == -1)
 483                 return -EINVAL;
 484
 485         spin_lock_irq(q->queue_lock);
 486         if (set)
 487                 queue_flag_set(QUEUE_FLAG_WC, q);
 488         else
 489                 queue_flag_clear(QUEUE_FLAG_WC, q);
 490         spin_unlock_irq(q->queue_lock);
 491
 492         return count;
 493 }
 494
 495 static ssize_t queue_dax_show(struct request_queue *q, char *page)
 496 {
 497         return queue_var_show(blk_queue_dax(q), page);
 498 }
 499
 500 static ssize_t print_stat(char *page, struct blk_rq_stat *stat, const char *pre)
 501 {
 502         return sprintf(page, "%s samples=%llu, mean=%lld, min=%lld, max=%lld\n",
 503                         pre, (long long) stat->nr_samples,
 504                         (long long) stat->mean, (long long) stat->min,
 505                         (long long) stat->max);
 506 }
 507
 508 static ssize_t queue_stats_show(struct request_queue *q, char *page)
 509 {
 510         struct blk_rq_stat stat[2];
 511         ssize_t ret;
 512
 513         blk_queue_stat_get(q, stat);
 514
 515         ret = print_stat(page, &stat[BLK_STAT_READ], "read :");
 516         ret += print_stat(page + ret, &stat[BLK_STAT_WRITE], "write:");
 517         return ret;
 518 }
 519
 520 static struct queue_sysfs_entry queue_requests_entry = {
 521         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 522         .show = queue_requests_show,
 523         .store = queue_requests_store,
 524 };
 525
 526 static struct queue_sysfs_entry queue_ra_entry = {
 527         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 528         .show = queue_ra_show,
 529         .store = queue_ra_store,
 530 };
 531
 532 static struct queue_sysfs_entry queue_max_sectors_entry = {
 533         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 534         .show = queue_max_sectors_show,
 535         .store = queue_max_sectors_store,
 536 };
 537
 538 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 539         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 540         .show = queue_max_hw_sectors_show,
 541 };
 542
 543 static struct queue_sysfs_entry queue_max_segments_entry = {
 544         .attr = {.name = "max_segments", .mode = S_IRUGO },
 545         .show = queue_max_segments_show,
 546 };
 547
 548 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
 549         .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
 550         .show = queue_max_integrity_segments_show,
 551 };
 552
 553 static struct queue_sysfs_entry queue_max_segment_size_entry = {
 554         .attr = {.name = "max_segment_size", .mode = S_IRUGO },
 555         .show = queue_max_segment_size_show,
 556 };
 557
 558 static struct queue_sysfs_entry queue_iosched_entry = {
 559         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 560         .show = elv_iosched_show,
 561         .store = elv_iosched_store,
 562 };
 563
 564 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 565         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 566         .show = queue_logical_block_size_show,
 567 };
 568
 569 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 570         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 571         .show = queue_logical_block_size_show,
 572 };
 573
 574 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 575         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 576         .show = queue_physical_block_size_show,
 577 };
 578
 579 static struct queue_sysfs_entry queue_chunk_sectors_entry = {
 580         .attr = {.name = "chunk_sectors", .mode = S_IRUGO },
 581         .show = queue_chunk_sectors_show,
 582 };
 583
 584 static struct queue_sysfs_entry queue_io_min_entry = {
 585         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 586         .show = queue_io_min_show,
 587 };
 588
 589 static struct queue_sysfs_entry queue_io_opt_entry = {
 590         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 591         .show = queue_io_opt_show,
 592 };
 593
 594 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 595         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
 596         .show = queue_discard_granularity_show,
 597 };
 598
 599 static struct queue_sysfs_entry queue_discard_max_hw_entry = {
 600         .attr = {.name = "discard_max_hw_bytes", .mode = S_IRUGO },
 601         .show = queue_discard_max_hw_show,
 602 };
 603
 604 static struct queue_sysfs_entry queue_discard_max_entry = {
 605         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO | S_IWUSR },
 606         .show = queue_discard_max_show,
 607         .store = queue_discard_max_store,
 608 };
 609
 610 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 611         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
 612         .show = queue_discard_zeroes_data_show,
 613 };
 614
 615 static struct queue_sysfs_entry queue_write_same_max_entry = {
 616         .attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
 617         .show = queue_write_same_max_show,
 618 };
 619
 620 static struct queue_sysfs_entry queue_write_zeroes_max_entry = {
 621         .attr = {.name = "write_zeroes_max_bytes", .mode = S_IRUGO },
 622         .show = queue_write_zeroes_max_show,
 623 };
 624
 625 static struct queue_sysfs_entry queue_nonrot_entry = {
 626         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 627         .show = queue_show_nonrot,
 628         .store = queue_store_nonrot,
 629 };
 630
 631 static struct queue_sysfs_entry queue_zoned_entry = {
 632         .attr = {.name = "zoned", .mode = S_IRUGO },
 633         .show = queue_zoned_show,
 634 };
 635
 636 static struct queue_sysfs_entry queue_nomerges_entry = {
 637         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 638         .show = queue_nomerges_show,
 639         .store = queue_nomerges_store,
 640 };
 641
 642 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 643         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 644         .show = queue_rq_affinity_show,
 645         .store = queue_rq_affinity_store,
 646 };
 647
 648 static struct queue_sysfs_entry queue_iostats_entry = {
 649         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 650         .show = queue_show_iostats,
 651         .store = queue_store_iostats,
 652 };
 653
 654 static struct queue_sysfs_entry queue_random_entry = {
 655         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
 656         .show = queue_show_random,
 657         .store = queue_store_random,
 658 };
 659
 660 static struct queue_sysfs_entry queue_poll_entry = {
 661         .attr = {.name = "io_poll", .mode = S_IRUGO | S_IWUSR },
 662         .show = queue_poll_show,
 663         .store = queue_poll_store,
 664 };
 665
 666 static struct queue_sysfs_entry queue_poll_delay_entry = {
 667         .attr = {.name = "io_poll_delay", .mode = S_IRUGO | S_IWUSR },
 668         .show = queue_poll_delay_show,
 669         .store = queue_poll_delay_store,
 670 };
 671
 672 static struct queue_sysfs_entry queue_wc_entry = {
 673         .attr = {.name = "write_cache", .mode = S_IRUGO | S_IWUSR },
 674         .show = queue_wc_show,
 675         .store = queue_wc_store,
 676 };
 677
 678 static struct queue_sysfs_entry queue_dax_entry = {
 679         .attr = {.name = "dax", .mode = S_IRUGO },
 680         .show = queue_dax_show,
 681 };
 682
 683 static struct queue_sysfs_entry queue_stats_entry = {
 684         .attr = {.name = "stats", .mode = S_IRUGO },
 685         .show = queue_stats_show,
 686 };
 687
 688 static struct queue_sysfs_entry queue_wb_lat_entry = {
 689         .attr = {.name = "wbt_lat_usec", .mode = S_IRUGO | S_IWUSR },
 690         .show = queue_wb_lat_show,
 691         .store = queue_wb_lat_store,
 692 };
 693
 694 static struct attribute *default_attrs[] = {
 695         &queue_requests_entry.attr,
 696         &queue_ra_entry.attr,
 697         &queue_max_hw_sectors_entry.attr,
 698         &queue_max_sectors_entry.attr,
 699         &queue_max_segments_entry.attr,
 700         &queue_max_integrity_segments_entry.attr,
 701         &queue_max_segment_size_entry.attr,
 702         &queue_iosched_entry.attr,
 703         &queue_hw_sector_size_entry.attr,
 704         &queue_logical_block_size_entry.attr,
 705         &queue_physical_block_size_entry.attr,
 706         &queue_chunk_sectors_entry.attr,
 707         &queue_io_min_entry.attr,
 708         &queue_io_opt_entry.attr,
 709         &queue_discard_granularity_entry.attr,
 710         &queue_discard_max_entry.attr,
 711         &queue_discard_max_hw_entry.attr,
 712         &queue_discard_zeroes_data_entry.attr,
 713         &queue_write_same_max_entry.attr,
 714         &queue_write_zeroes_max_entry.attr,
 715         &queue_nonrot_entry.attr,
 716         &queue_zoned_entry.attr,
 717         &queue_nomerges_entry.attr,
 718         &queue_rq_affinity_entry.attr,
 719         &queue_iostats_entry.attr,
 720         &queue_random_entry.attr,
 721         &queue_poll_entry.attr,
 722         &queue_wc_entry.attr,
 723         &queue_dax_entry.attr,
 724         &queue_stats_entry.attr,
 725         &queue_wb_lat_entry.attr,
 726         &queue_poll_delay_entry.attr,
 727         NULL,
 728 };
 729
 730 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 731
 732 static ssize_t
 733 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 734 {
 735         struct queue_sysfs_entry *entry = to_queue(attr);
 736         struct request_queue *q =
 737                 container_of(kobj, struct request_queue, kobj);
 738         ssize_t res;
 739
 740         if (!entry->show)
 741                 return -EIO;
 742         mutex_lock(&q->sysfs_lock);
 743         if (blk_queue_dying(q)) {
 744                 mutex_unlock(&q->sysfs_lock);
 745                 return -ENOENT;
 746         }
 747         res = entry->show(q, page);
 748         mutex_unlock(&q->sysfs_lock);
 749         return res;
 750 }
 751
 752 static ssize_t
 753 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 754                     const char *page, size_t length)
 755 {
 756         struct queue_sysfs_entry *entry = to_queue(attr);
 757         struct request_queue *q;
 758         ssize_t res;
 759
 760         if (!entry->store)
 761                 return -EIO;
 762
 763         q = container_of(kobj, struct request_queue, kobj);
 764         mutex_lock(&q->sysfs_lock);
 765         if (blk_queue_dying(q)) {
 766                 mutex_unlock(&q->sysfs_lock);
 767                 return -ENOENT;
 768         }
 769         res = entry->store(q, page, length);
 770         mutex_unlock(&q->sysfs_lock);
 771         return res;
 772 }
 773
 774 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 775 {
 776         struct request_queue *q = container_of(rcu_head, struct request_queue,
 777                                                rcu_head);
 778         kmem_cache_free(blk_requestq_cachep, q);
 779 }
 780
 781 /**
 782  * blk_release_queue: - release a &struct request_queue when it is no longer needed
 783  * @kobj:    the kobj belonging to the request queue to be released
 784  *
 785  * Description:
 786  *     blk_release_queue is the pair to blk_init_queue() or
 787  *     blk_queue_make_request().  It should be called when a request queue is
 788  *     being released; typically when a block device is being de-registered.
 789  *     Currently, its primary task it to free all the &struct request
 790  *     structures that were allocated to the queue and the queue itself.
 791  *
 792  * Note:
 793  *     The low level driver must have finished any outstanding requests first
 794  *     via blk_cleanup_queue().
 795  **/
 796 static void blk_release_queue(struct kobject *kobj)
 797 {
 798         struct request_queue *q =
 799                 container_of(kobj, struct request_queue, kobj);
 800
 801         wbt_exit(q);
 802         bdi_exit(&q->backing_dev_info);
 803         blkcg_exit_queue(q);
 804
 805         if (q->elevator) {
 806                 spin_lock_irq(q->queue_lock);
 807                 ioc_clear_queue(q);
 808                 spin_unlock_irq(q->queue_lock);
 809                 elevator_exit(q->elevator);
 810         }
 811
 812         blk_exit_rl(&q->root_rl);
 813
 814         if (q->queue_tags)
 815                 __blk_queue_free_tags(q);
 816
 817         if (!q->mq_ops)
 818                 blk_free_flush_queue(q->fq);
 819         else
 820                 blk_mq_release(q);
 821
 822         blk_trace_shutdown(q);
 823
 824         if (q->bio_split)
 825                 bioset_free(q->bio_split);
 826
 827         ida_simple_remove(&blk_queue_ida, q->id);
 828         call_rcu(&q->rcu_head, blk_free_queue_rcu);
 829 }
 830
 831 static const struct sysfs_ops queue_sysfs_ops = {
 832         .show   = queue_attr_show,
 833         .store  = queue_attr_store,
 834 };
 835
 836 struct kobj_type blk_queue_ktype = {
 837         .sysfs_ops      = &queue_sysfs_ops,
 838         .default_attrs  = default_attrs,
 839         .release        = blk_release_queue,
 840 };
 841
 842 static void blk_wb_init(struct request_queue *q)
 843 {
 844 #ifndef CONFIG_BLK_WBT_MQ
 845         if (q->mq_ops)
 846                 return;
 847 #endif
 848 #ifndef CONFIG_BLK_WBT_SQ
 849         if (q->request_fn)
 850                 return;
 851 #endif
 852
 853         /*
 854          * If this fails, we don't get throttling
 855          */
 856         wbt_init(q);
 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         /*
 869          * SCSI probing may synchronously create and destroy a lot of
 870          * request_queues for non-existent devices.  Shutting down a fully
 871          * functional queue takes measureable wallclock time as RCU grace
 872          * periods are involved.  To avoid excessive latency in these
 873          * cases, a request_queue starts out in a degraded mode which is
 874          * faster to shut down and is made fully functional here as
 875          * request_queues for non-existent devices never get registered.
 876          */
 877         if (!blk_queue_init_done(q)) {
 878                 queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
 879                 percpu_ref_switch_to_percpu(&q->q_usage_counter);
 880                 blk_queue_bypass_end(q);
 881         }
 882
 883         ret = blk_trace_init_sysfs(dev);
 884         if (ret)
 885                 return ret;
 886
 887         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 888         if (ret < 0) {
 889                 blk_trace_remove_sysfs(dev);
 890                 return ret;
 891         }
 892
 893         kobject_uevent(&q->kobj, KOBJ_ADD);
 894
 895         if (q->mq_ops)
 896                 blk_mq_register_dev(dev, q);
 897
 898         blk_wb_init(q);
 899
 900         if (!q->request_fn)
 901                 return 0;
 902
 903         ret = elv_register_queue(q);
 904         if (ret) {
 905                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 906                 kobject_del(&q->kobj);
 907                 blk_trace_remove_sysfs(dev);
 908                 kobject_put(&dev->kobj);
 909                 return ret;
 910         }
 911
 912         return 0;
 913 }
 914
 915 void blk_unregister_queue(struct gendisk *disk)
 916 {
 917         struct request_queue *q = disk->queue;
 918
 919         if (WARN_ON(!q))
 920                 return;
 921
 922         if (q->mq_ops)
 923                 blk_mq_unregister_dev(disk_to_dev(disk), q);
 924
 925         if (q->request_fn)
 926                 elv_unregister_queue(q);
 927
 928         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 929         kobject_del(&q->kobj);
 930         blk_trace_remove_sysfs(disk_to_dev(disk));
 931         kobject_put(&disk_to_dev(disk)->kobj);
 932 }