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