block/blk-sysfs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Functions related to sysfs handling
   4  */
   5 #include <linux/kernel.h>
   6 #include <linux/slab.h>
   7 #include <linux/module.h>
   8 #include <linux/bio.h>
   9 #include <linux/blkdev.h>
  10 #include <linux/backing-dev.h>
  11 #include <linux/blktrace_api.h>
  12 #include <linux/blk-mq.h>
  13 #include <linux/blk-cgroup.h>
  14
  15 #include "blk.h"
  16 #include "blk-mq.h"
  17 #include "blk-mq-debugfs.h"
  18 #include "blk-wbt.h"
  19
  20 struct queue_sysfs_entry {
  21         struct attribute attr;
  22         ssize_t (*show)(struct request_queue *, char *);
  23         ssize_t (*store)(struct request_queue *, const char *, size_t);
  24 };
  25
  26 static ssize_t
  27 queue_var_show(unsigned long var, char *page)
  28 {
  29         return sprintf(page, "%lu\n", var);
  30 }
  31
  32 static ssize_t
  33 queue_var_store(unsigned long *var, const char *page, size_t count)
  34 {
  35         int err;
  36         unsigned long v;
  37
  38         err = kstrtoul(page, 10, &v);
  39         if (err || v > UINT_MAX)
  40                 return -EINVAL;
  41
  42         *var = v;
  43
  44         return count;
  45 }
  46
  47 static ssize_t queue_var_store64(s64 *var, const char *page)
  48 {
  49         int err;
  50         s64 v;
  51
  52         err = kstrtos64(page, 10, &v);
  53         if (err < 0)
  54                 return err;
  55
  56         *var = v;
  57         return 0;
  58 }
  59
  60 static ssize_t queue_requests_show(struct request_queue *q, char *page)
  61 {
  62         return queue_var_show(q->nr_requests, (page));
  63 }
  64
  65 static ssize_t
  66 queue_requests_store(struct request_queue *q, const char *page, size_t count)
  67 {
  68         unsigned long nr;
  69         int ret, err;
  70
  71         if (!queue_is_mq(q))
  72                 return -EINVAL;
  73
  74         ret = queue_var_store(&nr, page, count);
  75         if (ret < 0)
  76                 return ret;
  77
  78         if (nr < BLKDEV_MIN_RQ)
  79                 nr = BLKDEV_MIN_RQ;
  80
  81         err = blk_mq_update_nr_requests(q, nr);
  82         if (err)
  83                 return err;
  84
  85         return ret;
  86 }
  87
  88 static ssize_t queue_ra_show(struct request_queue *q, char *page)
  89 {
  90         unsigned long ra_kb = q->backing_dev_info->ra_pages <<
  91                                         (PAGE_SHIFT - 10);
  92
  93         return queue_var_show(ra_kb, (page));
  94 }
  95
  96 static ssize_t
  97 queue_ra_store(struct request_queue *q, const char *page, size_t count)
  98 {
  99         unsigned long ra_kb;
 100         ssize_t ret = queue_var_store(&ra_kb, page, count);
 101
 102         if (ret < 0)
 103                 return ret;
 104
 105         q->backing_dev_info->ra_pages = ra_kb >> (PAGE_SHIFT - 10);
 106
 107         return ret;
 108 }
 109
 110 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
 111 {
 112         int max_sectors_kb = queue_max_sectors(q) >> 1;
 113
 114         return queue_var_show(max_sectors_kb, (page));
 115 }
 116
 117 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
 118 {
 119         return queue_var_show(queue_max_segments(q), (page));
 120 }
 121
 122 static ssize_t queue_max_discard_segments_show(struct request_queue *q,
 123                 char *page)
 124 {
 125         return queue_var_show(queue_max_discard_segments(q), (page));
 126 }
 127
 128 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
 129 {
 130         return queue_var_show(q->limits.max_integrity_segments, (page));
 131 }
 132
 133 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 134 {
 135         return queue_var_show(queue_max_segment_size(q), (page));
 136 }
 137
 138 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 139 {
 140         return queue_var_show(queue_logical_block_size(q), page);
 141 }
 142
 143 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 144 {
 145         return queue_var_show(queue_physical_block_size(q), page);
 146 }
 147
 148 static ssize_t queue_chunk_sectors_show(struct request_queue *q, char *page)
 149 {
 150         return queue_var_show(q->limits.chunk_sectors, page);
 151 }
 152
 153 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 154 {
 155         return queue_var_show(queue_io_min(q), page);
 156 }
 157
 158 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 159 {
 160         return queue_var_show(queue_io_opt(q), page);
 161 }
 162
 163 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 164 {
 165         return queue_var_show(q->limits.discard_granularity, page);
 166 }
 167
 168 static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
 169 {
 170
 171         return sprintf(page, "%llu\n",
 172                 (unsigned long long)q->limits.max_hw_discard_sectors << 9);
 173 }
 174
 175 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 176 {
 177         return sprintf(page, "%llu\n",
 178                        (unsigned long long)q->limits.max_discard_sectors << 9);
 179 }
 180
 181 static ssize_t queue_discard_max_store(struct request_queue *q,
 182                                        const char *page, size_t count)
 183 {
 184         unsigned long max_discard;
 185         ssize_t ret = queue_var_store(&max_discard, page, count);
 186
 187         if (ret < 0)
 188                 return ret;
 189
 190         if (max_discard & (q->limits.discard_granularity - 1))
 191                 return -EINVAL;
 192
 193         max_discard >>= 9;
 194         if (max_discard > UINT_MAX)
 195                 return -EINVAL;
 196
 197         if (max_discard > q->limits.max_hw_discard_sectors)
 198                 max_discard = q->limits.max_hw_discard_sectors;
 199
 200         q->limits.max_discard_sectors = max_discard;
 201         return ret;
 202 }
 203
 204 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 205 {
 206         return queue_var_show(0, page);
 207 }
 208
 209 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
 210 {
 211         return sprintf(page, "%llu\n",
 212                 (unsigned long long)q->limits.max_write_same_sectors << 9);
 213 }
 214
 215 static ssize_t queue_write_zeroes_max_show(struct request_queue *q, char *page)
 216 {
 217         return sprintf(page, "%llu\n",
 218                 (unsigned long long)q->limits.max_write_zeroes_sectors << 9);
 219 }
 220
 221 static ssize_t
 222 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 223 {
 224         unsigned long max_sectors_kb,
 225                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 226                         page_kb = 1 << (PAGE_SHIFT - 10);
 227         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 228
 229         if (ret < 0)
 230                 return ret;
 231
 232         max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, (unsigned long)
 233                                          q->limits.max_dev_sectors >> 1);
 234
 235         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 236                 return -EINVAL;
 237
 238         spin_lock_irq(&q->queue_lock);
 239         q->limits.max_sectors = max_sectors_kb << 1;
 240         q->backing_dev_info->io_pages = max_sectors_kb >> (PAGE_SHIFT - 10);
 241         spin_unlock_irq(&q->queue_lock);
 242
 243         return ret;
 244 }
 245
 246 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 247 {
 248         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 249
 250         return queue_var_show(max_hw_sectors_kb, (page));
 251 }
 252
 253 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 254 static ssize_t                                                          \
 255 queue_show_##name(struct request_queue *q, char *page)                  \
 256 {                                                                       \
 257         int bit;                                                        \
 258         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 259         return queue_var_show(neg ? !bit : bit, page);                  \
 260 }                                                                       \
 261 static ssize_t                                                          \
 262 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
 263 {                                                                       \
 264         unsigned long val;                                              \
 265         ssize_t ret;                                                    \
 266         ret = queue_var_store(&val, page, count);                       \
 267         if (ret < 0)                                                    \
 268                  return ret;                                            \
 269         if (neg)                                                        \
 270                 val = !val;                                             \
 271                                                                         \
 272         if (val)                                                        \
 273                 blk_queue_flag_set(QUEUE_FLAG_##flag, q);               \
 274         else                                                            \
 275                 blk_queue_flag_clear(QUEUE_FLAG_##flag, q);             \
 276         return ret;                                                     \
 277 }
 278
 279 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 280 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 281 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 282 #undef QUEUE_SYSFS_BIT_FNS
 283
 284 static ssize_t queue_zoned_show(struct request_queue *q, char *page)
 285 {
 286         switch (blk_queue_zoned_model(q)) {
 287         case BLK_ZONED_HA:
 288                 return sprintf(page, "host-aware\n");
 289         case BLK_ZONED_HM:
 290                 return sprintf(page, "host-managed\n");
 291         default:
 292                 return sprintf(page, "none\n");
 293         }
 294 }
 295
 296 static ssize_t queue_nr_zones_show(struct request_queue *q, char *page)
 297 {
 298         return queue_var_show(blk_queue_nr_zones(q), page);
 299 }
 300
 301 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 302 {
 303         return queue_var_show((blk_queue_nomerges(q) << 1) |
 304                                blk_queue_noxmerges(q), page);
 305 }
 306
 307 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 308                                     size_t count)
 309 {
 310         unsigned long nm;
 311         ssize_t ret = queue_var_store(&nm, page, count);
 312
 313         if (ret < 0)
 314                 return ret;
 315
 316         blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 317         blk_queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 318         if (nm == 2)
 319                 blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 320         else if (nm)
 321                 blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 322
 323         return ret;
 324 }
 325
 326 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 327 {
 328         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 329         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 330
 331         return queue_var_show(set << force, page);
 332 }
 333
 334 static ssize_t
 335 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 336 {
 337         ssize_t ret = -EINVAL;
 338 #ifdef CONFIG_SMP
 339         unsigned long val;
 340
 341         ret = queue_var_store(&val, page, count);
 342         if (ret < 0)
 343                 return ret;
 344
 345         if (val == 2) {
 346                 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 347                 blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 348         } else if (val == 1) {
 349                 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 350                 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 351         } else if (val == 0) {
 352                 blk_queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 353                 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 354         }
 355 #endif
 356         return ret;
 357 }
 358
 359 static ssize_t queue_poll_delay_show(struct request_queue *q, char *page)
 360 {
 361         int val;
 362
 363         if (q->poll_nsec == -1)
 364                 val = -1;
 365         else
 366                 val = q->poll_nsec / 1000;
 367
 368         return sprintf(page, "%d\n", val);
 369 }
 370
 371 static ssize_t queue_poll_delay_store(struct request_queue *q, const char *page,
 372                                 size_t count)
 373 {
 374         int err, val;
 375
 376         if (!q->mq_ops || !q->mq_ops->poll)
 377                 return -EINVAL;
 378
 379         err = kstrtoint(page, 10, &val);
 380         if (err < 0)
 381                 return err;
 382
 383         if (val == -1)
 384                 q->poll_nsec = -1;
 385         else
 386                 q->poll_nsec = val * 1000;
 387
 388         return count;
 389 }
 390
 391 static ssize_t queue_poll_show(struct request_queue *q, char *page)
 392 {
 393         return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
 394 }
 395
 396 static ssize_t queue_poll_store(struct request_queue *q, const char *page,
 397                                 size_t count)
 398 {
 399         unsigned long poll_on;
 400         ssize_t ret;
 401
 402         if (!q->tag_set || q->tag_set->nr_maps <= HCTX_TYPE_POLL ||
 403             !q->tag_set->map[HCTX_TYPE_POLL].nr_queues)
 404                 return -EINVAL;
 405
 406         ret = queue_var_store(&poll_on, page, count);
 407         if (ret < 0)
 408                 return ret;
 409
 410         if (poll_on)
 411                 blk_queue_flag_set(QUEUE_FLAG_POLL, q);
 412         else
 413                 blk_queue_flag_clear(QUEUE_FLAG_POLL, q);
 414
 415         return ret;
 416 }
 417
 418 static ssize_t queue_io_timeout_show(struct request_queue *q, char *page)
 419 {
 420         return sprintf(page, "%u\n", jiffies_to_msecs(q->rq_timeout));
 421 }
 422
 423 static ssize_t queue_io_timeout_store(struct request_queue *q, const char *page,
 424                                   size_t count)
 425 {
 426         unsigned int val;
 427         int err;
 428
 429         err = kstrtou32(page, 10, &val);
 430         if (err || val == 0)
 431                 return -EINVAL;
 432
 433         blk_queue_rq_timeout(q, msecs_to_jiffies(val));
 434
 435         return count;
 436 }
 437
 438 static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
 439 {
 440         if (!wbt_rq_qos(q))
 441                 return -EINVAL;
 442
 443         return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));
 444 }
 445
 446 static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
 447                                   size_t count)
 448 {
 449         struct rq_qos *rqos;
 450         ssize_t ret;
 451         s64 val;
 452
 453         ret = queue_var_store64(&val, page);
 454         if (ret < 0)
 455                 return ret;
 456         if (val < -1)
 457                 return -EINVAL;
 458
 459         rqos = wbt_rq_qos(q);
 460         if (!rqos) {
 461                 ret = wbt_init(q);
 462                 if (ret)
 463                         return ret;
 464         }
 465
 466         if (val == -1)
 467                 val = wbt_default_latency_nsec(q);
 468         else if (val >= 0)
 469                 val *= 1000ULL;
 470
 471         if (wbt_get_min_lat(q) == val)
 472                 return count;
 473
 474         /*
 475          * Ensure that the queue is idled, in case the latency update
 476          * ends up either enabling or disabling wbt completely. We can't
 477          * have IO inflight if that happens.
 478          */
 479         blk_mq_freeze_queue(q);
 480         blk_mq_quiesce_queue(q);
 481
 482         wbt_set_min_lat(q, val);
 483         wbt_update_limits(q);
 484
 485         blk_mq_unquiesce_queue(q);
 486         blk_mq_unfreeze_queue(q);
 487
 488         return count;
 489 }
 490
 491 static ssize_t queue_wc_show(struct request_queue *q, char *page)
 492 {
 493         if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
 494                 return sprintf(page, "write back\n");
 495
 496         return sprintf(page, "write through\n");
 497 }
 498
 499 static ssize_t queue_wc_store(struct request_queue *q, const char *page,
 500                               size_t count)
 501 {
 502         int set = -1;
 503
 504         if (!strncmp(page, "write back", 10))
 505                 set = 1;
 506         else if (!strncmp(page, "write through", 13) ||
 507                  !strncmp(page, "none", 4))
 508                 set = 0;
 509
 510         if (set == -1)
 511                 return -EINVAL;
 512
 513         if (set)
 514                 blk_queue_flag_set(QUEUE_FLAG_WC, q);
 515         else
 516                 blk_queue_flag_clear(QUEUE_FLAG_WC, q);
 517
 518         return count;
 519 }
 520
 521 static ssize_t queue_fua_show(struct request_queue *q, char *page)
 522 {
 523         return sprintf(page, "%u\n", test_bit(QUEUE_FLAG_FUA, &q->queue_flags));
 524 }
 525
 526 static ssize_t queue_dax_show(struct request_queue *q, char *page)
 527 {
 528         return queue_var_show(blk_queue_dax(q), page);
 529 }
 530
 531 static struct queue_sysfs_entry queue_requests_entry = {
 532         .attr = {.name = "nr_requests", .mode = 0644 },
 533         .show = queue_requests_show,
 534         .store = queue_requests_store,
 535 };
 536
 537 static struct queue_sysfs_entry queue_ra_entry = {
 538         .attr = {.name = "read_ahead_kb", .mode = 0644 },
 539         .show = queue_ra_show,
 540         .store = queue_ra_store,
 541 };
 542
 543 static struct queue_sysfs_entry queue_max_sectors_entry = {
 544         .attr = {.name = "max_sectors_kb", .mode = 0644 },
 545         .show = queue_max_sectors_show,
 546         .store = queue_max_sectors_store,
 547 };
 548
 549 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 550         .attr = {.name = "max_hw_sectors_kb", .mode = 0444 },
 551         .show = queue_max_hw_sectors_show,
 552 };
 553
 554 static struct queue_sysfs_entry queue_max_segments_entry = {
 555         .attr = {.name = "max_segments", .mode = 0444 },
 556         .show = queue_max_segments_show,
 557 };
 558
 559 static struct queue_sysfs_entry queue_max_discard_segments_entry = {
 560         .attr = {.name = "max_discard_segments", .mode = 0444 },
 561         .show = queue_max_discard_segments_show,
 562 };
 563
 564 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
 565         .attr = {.name = "max_integrity_segments", .mode = 0444 },
 566         .show = queue_max_integrity_segments_show,
 567 };
 568
 569 static struct queue_sysfs_entry queue_max_segment_size_entry = {
 570         .attr = {.name = "max_segment_size", .mode = 0444 },
 571         .show = queue_max_segment_size_show,
 572 };
 573
 574 static struct queue_sysfs_entry queue_iosched_entry = {
 575         .attr = {.name = "scheduler", .mode = 0644 },
 576         .show = elv_iosched_show,
 577         .store = elv_iosched_store,
 578 };
 579
 580 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 581         .attr = {.name = "hw_sector_size", .mode = 0444 },
 582         .show = queue_logical_block_size_show,
 583 };
 584
 585 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 586         .attr = {.name = "logical_block_size", .mode = 0444 },
 587         .show = queue_logical_block_size_show,
 588 };
 589
 590 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 591         .attr = {.name = "physical_block_size", .mode = 0444 },
 592         .show = queue_physical_block_size_show,
 593 };
 594
 595 static struct queue_sysfs_entry queue_chunk_sectors_entry = {
 596         .attr = {.name = "chunk_sectors", .mode = 0444 },
 597         .show = queue_chunk_sectors_show,
 598 };
 599
 600 static struct queue_sysfs_entry queue_io_min_entry = {
 601         .attr = {.name = "minimum_io_size", .mode = 0444 },
 602         .show = queue_io_min_show,
 603 };
 604
 605 static struct queue_sysfs_entry queue_io_opt_entry = {
 606         .attr = {.name = "optimal_io_size", .mode = 0444 },
 607         .show = queue_io_opt_show,
 608 };
 609
 610 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 611         .attr = {.name = "discard_granularity", .mode = 0444 },
 612         .show = queue_discard_granularity_show,
 613 };
 614
 615 static struct queue_sysfs_entry queue_discard_max_hw_entry = {
 616         .attr = {.name = "discard_max_hw_bytes", .mode = 0444 },
 617         .show = queue_discard_max_hw_show,
 618 };
 619
 620 static struct queue_sysfs_entry queue_discard_max_entry = {
 621         .attr = {.name = "discard_max_bytes", .mode = 0644 },
 622         .show = queue_discard_max_show,
 623         .store = queue_discard_max_store,
 624 };
 625
 626 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 627         .attr = {.name = "discard_zeroes_data", .mode = 0444 },
 628         .show = queue_discard_zeroes_data_show,
 629 };
 630
 631 static struct queue_sysfs_entry queue_write_same_max_entry = {
 632         .attr = {.name = "write_same_max_bytes", .mode = 0444 },
 633         .show = queue_write_same_max_show,
 634 };
 635
 636 static struct queue_sysfs_entry queue_write_zeroes_max_entry = {
 637         .attr = {.name = "write_zeroes_max_bytes", .mode = 0444 },
 638         .show = queue_write_zeroes_max_show,
 639 };
 640
 641 static struct queue_sysfs_entry queue_nonrot_entry = {
 642         .attr = {.name = "rotational", .mode = 0644 },
 643         .show = queue_show_nonrot,
 644         .store = queue_store_nonrot,
 645 };
 646
 647 static struct queue_sysfs_entry queue_zoned_entry = {
 648         .attr = {.name = "zoned", .mode = 0444 },
 649         .show = queue_zoned_show,
 650 };
 651
 652 static struct queue_sysfs_entry queue_nr_zones_entry = {
 653         .attr = {.name = "nr_zones", .mode = 0444 },
 654         .show = queue_nr_zones_show,
 655 };
 656
 657 static struct queue_sysfs_entry queue_nomerges_entry = {
 658         .attr = {.name = "nomerges", .mode = 0644 },
 659         .show = queue_nomerges_show,
 660         .store = queue_nomerges_store,
 661 };
 662
 663 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 664         .attr = {.name = "rq_affinity", .mode = 0644 },
 665         .show = queue_rq_affinity_show,
 666         .store = queue_rq_affinity_store,
 667 };
 668
 669 static struct queue_sysfs_entry queue_iostats_entry = {
 670         .attr = {.name = "iostats", .mode = 0644 },
 671         .show = queue_show_iostats,
 672         .store = queue_store_iostats,
 673 };
 674
 675 static struct queue_sysfs_entry queue_random_entry = {
 676         .attr = {.name = "add_random", .mode = 0644 },
 677         .show = queue_show_random,
 678         .store = queue_store_random,
 679 };
 680
 681 static struct queue_sysfs_entry queue_poll_entry = {
 682         .attr = {.name = "io_poll", .mode = 0644 },
 683         .show = queue_poll_show,
 684         .store = queue_poll_store,
 685 };
 686
 687 static struct queue_sysfs_entry queue_poll_delay_entry = {
 688         .attr = {.name = "io_poll_delay", .mode = 0644 },
 689         .show = queue_poll_delay_show,
 690         .store = queue_poll_delay_store,
 691 };
 692
 693 static struct queue_sysfs_entry queue_wc_entry = {
 694         .attr = {.name = "write_cache", .mode = 0644 },
 695         .show = queue_wc_show,
 696         .store = queue_wc_store,
 697 };
 698
 699 static struct queue_sysfs_entry queue_fua_entry = {
 700         .attr = {.name = "fua", .mode = 0444 },
 701         .show = queue_fua_show,
 702 };
 703
 704 static struct queue_sysfs_entry queue_dax_entry = {
 705         .attr = {.name = "dax", .mode = 0444 },
 706         .show = queue_dax_show,
 707 };
 708
 709 static struct queue_sysfs_entry queue_io_timeout_entry = {
 710         .attr = {.name = "io_timeout", .mode = 0644 },
 711         .show = queue_io_timeout_show,
 712         .store = queue_io_timeout_store,
 713 };
 714
 715 static struct queue_sysfs_entry queue_wb_lat_entry = {
 716         .attr = {.name = "wbt_lat_usec", .mode = 0644 },
 717         .show = queue_wb_lat_show,
 718         .store = queue_wb_lat_store,
 719 };
 720
 721 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 722 static struct queue_sysfs_entry throtl_sample_time_entry = {
 723         .attr = {.name = "throttle_sample_time", .mode = 0644 },
 724         .show = blk_throtl_sample_time_show,
 725         .store = blk_throtl_sample_time_store,
 726 };
 727 #endif
 728
 729 static struct attribute *default_attrs[] = {
 730         &queue_requests_entry.attr,
 731         &queue_ra_entry.attr,
 732         &queue_max_hw_sectors_entry.attr,
 733         &queue_max_sectors_entry.attr,
 734         &queue_max_segments_entry.attr,
 735         &queue_max_discard_segments_entry.attr,
 736         &queue_max_integrity_segments_entry.attr,
 737         &queue_max_segment_size_entry.attr,
 738         &queue_iosched_entry.attr,
 739         &queue_hw_sector_size_entry.attr,
 740         &queue_logical_block_size_entry.attr,
 741         &queue_physical_block_size_entry.attr,
 742         &queue_chunk_sectors_entry.attr,
 743         &queue_io_min_entry.attr,
 744         &queue_io_opt_entry.attr,
 745         &queue_discard_granularity_entry.attr,
 746         &queue_discard_max_entry.attr,
 747         &queue_discard_max_hw_entry.attr,
 748         &queue_discard_zeroes_data_entry.attr,
 749         &queue_write_same_max_entry.attr,
 750         &queue_write_zeroes_max_entry.attr,
 751         &queue_nonrot_entry.attr,
 752         &queue_zoned_entry.attr,
 753         &queue_nr_zones_entry.attr,
 754         &queue_nomerges_entry.attr,
 755         &queue_rq_affinity_entry.attr,
 756         &queue_iostats_entry.attr,
 757         &queue_random_entry.attr,
 758         &queue_poll_entry.attr,
 759         &queue_wc_entry.attr,
 760         &queue_fua_entry.attr,
 761         &queue_dax_entry.attr,
 762         &queue_wb_lat_entry.attr,
 763         &queue_poll_delay_entry.attr,
 764         &queue_io_timeout_entry.attr,
 765 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 766         &throtl_sample_time_entry.attr,
 767 #endif
 768         NULL,
 769 };
 770
 771 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 772
 773 static ssize_t
 774 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 775 {
 776         struct queue_sysfs_entry *entry = to_queue(attr);
 777         struct request_queue *q =
 778                 container_of(kobj, struct request_queue, kobj);
 779         ssize_t res;
 780
 781         if (!entry->show)
 782                 return -EIO;
 783         mutex_lock(&q->sysfs_lock);
 784         if (blk_queue_dying(q)) {
 785                 mutex_unlock(&q->sysfs_lock);
 786                 return -ENOENT;
 787         }
 788         res = entry->show(q, page);
 789         mutex_unlock(&q->sysfs_lock);
 790         return res;
 791 }
 792
 793 static ssize_t
 794 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 795                     const char *page, size_t length)
 796 {
 797         struct queue_sysfs_entry *entry = to_queue(attr);
 798         struct request_queue *q;
 799         ssize_t res;
 800
 801         if (!entry->store)
 802                 return -EIO;
 803
 804         q = container_of(kobj, struct request_queue, kobj);
 805         mutex_lock(&q->sysfs_lock);
 806         if (blk_queue_dying(q)) {
 807                 mutex_unlock(&q->sysfs_lock);
 808                 return -ENOENT;
 809         }
 810         res = entry->store(q, page, length);
 811         mutex_unlock(&q->sysfs_lock);
 812         return res;
 813 }
 814
 815 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 816 {
 817         struct request_queue *q = container_of(rcu_head, struct request_queue,
 818                                                rcu_head);
 819         kmem_cache_free(blk_requestq_cachep, q);
 820 }
 821
 822 /**
 823  * __blk_release_queue - release a request queue
 824  * @work: pointer to the release_work member of the request queue to be released
 825  *
 826  * Description:
 827  *     This function is called when a block device is being unregistered. The
 828  *     process of releasing a request queue starts with blk_cleanup_queue, which
 829  *     set the appropriate flags and then calls blk_put_queue, that decrements
 830  *     the reference counter of the request queue. Once the reference counter
 831  *     of the request queue reaches zero, blk_release_queue is called to release
 832  *     all allocated resources of the request queue.
 833  */
 834 static void __blk_release_queue(struct work_struct *work)
 835 {
 836         struct request_queue *q = container_of(work, typeof(*q), release_work);
 837
 838         if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags))
 839                 blk_stat_remove_callback(q, q->poll_cb);
 840         blk_stat_free_callback(q->poll_cb);
 841
 842         if (!blk_queue_dead(q)) {
 843                 /*
 844                  * Last reference was dropped without having called
 845                  * blk_cleanup_queue().
 846                  */
 847                 WARN_ONCE(blk_queue_init_done(q),
 848                           "request queue %p has been registered but blk_cleanup_queue() has not been called for that queue\n",
 849                           q);
 850                 blk_exit_queue(q);
 851         }
 852
 853         WARN(blk_queue_root_blkg(q),
 854              "request queue %p is being released but it has not yet been removed from the blkcg controller\n",
 855              q);
 856
 857         blk_free_queue_stats(q->stats);
 858
 859         blk_queue_free_zone_bitmaps(q);
 860
 861         if (queue_is_mq(q))
 862                 blk_mq_release(q);
 863
 864         blk_trace_shutdown(q);
 865
 866         if (queue_is_mq(q))
 867                 blk_mq_debugfs_unregister(q);
 868
 869         bioset_exit(&q->bio_split);
 870
 871         ida_simple_remove(&blk_queue_ida, q->id);
 872         call_rcu(&q->rcu_head, blk_free_queue_rcu);
 873 }
 874
 875 static void blk_release_queue(struct kobject *kobj)
 876 {
 877         struct request_queue *q =
 878                 container_of(kobj, struct request_queue, kobj);
 879
 880         INIT_WORK(&q->release_work, __blk_release_queue);
 881         schedule_work(&q->release_work);
 882 }
 883
 884 static const struct sysfs_ops queue_sysfs_ops = {
 885         .show   = queue_attr_show,
 886         .store  = queue_attr_store,
 887 };
 888
 889 struct kobj_type blk_queue_ktype = {
 890         .sysfs_ops      = &queue_sysfs_ops,
 891         .default_attrs  = default_attrs,
 892         .release        = blk_release_queue,
 893 };
 894
 895 /**
 896  * blk_register_queue - register a block layer queue with sysfs
 897  * @disk: Disk of which the request queue should be registered with sysfs.
 898  */
 899 int blk_register_queue(struct gendisk *disk)
 900 {
 901         int ret;
 902         struct device *dev = disk_to_dev(disk);
 903         struct request_queue *q = disk->queue;
 904
 905         if (WARN_ON(!q))
 906                 return -ENXIO;
 907
 908         WARN_ONCE(test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags),
 909                   "%s is registering an already registered queue\n",
 910                   kobject_name(&dev->kobj));
 911         blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);
 912
 913         /*
 914          * SCSI probing may synchronously create and destroy a lot of
 915          * request_queues for non-existent devices.  Shutting down a fully
 916          * functional queue takes measureable wallclock time as RCU grace
 917          * periods are involved.  To avoid excessive latency in these
 918          * cases, a request_queue starts out in a degraded mode which is
 919          * faster to shut down and is made fully functional here as
 920          * request_queues for non-existent devices never get registered.
 921          */
 922         if (!blk_queue_init_done(q)) {
 923                 blk_queue_flag_set(QUEUE_FLAG_INIT_DONE, q);
 924                 percpu_ref_switch_to_percpu(&q->q_usage_counter);
 925         }
 926
 927         ret = blk_trace_init_sysfs(dev);
 928         if (ret)
 929                 return ret;
 930
 931         /* Prevent changes through sysfs until registration is completed. */
 932         mutex_lock(&q->sysfs_lock);
 933
 934         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 935         if (ret < 0) {
 936                 blk_trace_remove_sysfs(dev);
 937                 goto unlock;
 938         }
 939
 940         if (queue_is_mq(q)) {
 941                 __blk_mq_register_dev(dev, q);
 942                 blk_mq_debugfs_register(q);
 943         }
 944
 945         kobject_uevent(&q->kobj, KOBJ_ADD);
 946
 947         wbt_enable_default(q);
 948
 949         blk_throtl_register_queue(q);
 950
 951         if (q->elevator) {
 952                 ret = elv_register_queue(q);
 953                 if (ret) {
 954                         mutex_unlock(&q->sysfs_lock);
 955                         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 956                         kobject_del(&q->kobj);
 957                         blk_trace_remove_sysfs(dev);
 958                         kobject_put(&dev->kobj);
 959                         return ret;
 960                 }
 961         }
 962         ret = 0;
 963 unlock:
 964         mutex_unlock(&q->sysfs_lock);
 965         return ret;
 966 }
 967 EXPORT_SYMBOL_GPL(blk_register_queue);
 968
 969 /**
 970  * blk_unregister_queue - counterpart of blk_register_queue()
 971  * @disk: Disk of which the request queue should be unregistered from sysfs.
 972  *
 973  * Note: the caller is responsible for guaranteeing that this function is called
 974  * after blk_register_queue() has finished.
 975  */
 976 void blk_unregister_queue(struct gendisk *disk)
 977 {
 978         struct request_queue *q = disk->queue;
 979
 980         if (WARN_ON(!q))
 981                 return;
 982
 983         /* Return early if disk->queue was never registered. */
 984         if (!test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags))
 985                 return;
 986
 987         /*
 988          * Since sysfs_remove_dir() prevents adding new directory entries
 989          * before removal of existing entries starts, protect against
 990          * concurrent elv_iosched_store() calls.
 991          */
 992         mutex_lock(&q->sysfs_lock);
 993
 994         blk_queue_flag_clear(QUEUE_FLAG_REGISTERED, q);
 995
 996         /*
 997          * Remove the sysfs attributes before unregistering the queue data
 998          * structures that can be modified through sysfs.
 999          */
1000         if (queue_is_mq(q))
1001                 blk_mq_unregister_dev(disk_to_dev(disk), q);
1002         mutex_unlock(&q->sysfs_lock);
1003
1004         kobject_uevent(&q->kobj, KOBJ_REMOVE);
1005         kobject_del(&q->kobj);
1006         blk_trace_remove_sysfs(disk_to_dev(disk));
1007
1008         mutex_lock(&q->sysfs_lock);
1009         if (q->elevator)
1010                 elv_unregister_queue(q);
1011         mutex_unlock(&q->sysfs_lock);
1012
1013         kobject_put(&disk_to_dev(disk)->kobj);
1014 }