block/blk-sysfs.c

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