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