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 #include <linux/debugfs.h>
  15
  16 #include "blk.h"
  17 #include "blk-mq.h"
  18 #include "blk-mq-debugfs.h"
  19 #include "blk-wbt.h"
  20
  21 struct queue_sysfs_entry {
  22         struct attribute attr;
  23         ssize_t (*show)(struct request_queue *, char *);
  24         ssize_t (*store)(struct request_queue *, const char *, size_t);
  25 };
  26
  27 static ssize_t
  28 queue_var_show(unsigned long var, char *page)
  29 {
  30         return sprintf(page, "%lu\n", var);
  31 }
  32
  33 static ssize_t
  34 queue_var_store(unsigned long *var, const char *page, size_t count)
  35 {
  36         int err;
  37         unsigned long v;
  38
  39         err = kstrtoul(page, 10, &v);
  40         if (err || v > UINT_MAX)
  41                 return -EINVAL;
  42
  43         *var = v;
  44
  45         return count;
  46 }
  47
  48 static ssize_t queue_var_store64(s64 *var, const char *page)
  49 {
  50         int err;
  51         s64 v;
  52
  53         err = kstrtos64(page, 10, &v);
  54         if (err < 0)
  55                 return err;
  56
  57         *var = v;
  58         return 0;
  59 }
  60
  61 static ssize_t queue_requests_show(struct request_queue *q, char *page)
  62 {
  63         return queue_var_show(q->nr_requests, (page));
  64 }
  65
  66 static ssize_t
  67 queue_requests_store(struct request_queue *q, const char *page, size_t count)
  68 {
  69         unsigned long nr;
  70         int ret, err;
  71
  72         if (!queue_is_mq(q))
  73                 return -EINVAL;
  74
  75         ret = queue_var_store(&nr, page, count);
  76         if (ret < 0)
  77                 return ret;
  78
  79         if (nr < BLKDEV_MIN_RQ)
  80                 nr = BLKDEV_MIN_RQ;
  81
  82         err = blk_mq_update_nr_requests(q, nr);
  83         if (err)
  84                 return err;
  85
  86         return ret;
  87 }
  88
  89 static ssize_t queue_ra_show(struct request_queue *q, char *page)
  90 {
  91         unsigned long ra_kb = q->backing_dev_info->ra_pages <<
  92                                         (PAGE_SHIFT - 10);
  93
  94         return queue_var_show(ra_kb, (page));
  95 }
  96
  97 static ssize_t
  98 queue_ra_store(struct request_queue *q, const char *page, size_t count)
  99 {
 100         unsigned long ra_kb;
 101         ssize_t ret = queue_var_store(&ra_kb, page, count);
 102
 103         if (ret < 0)
 104                 return ret;
 105
 106         q->backing_dev_info->ra_pages = ra_kb >> (PAGE_SHIFT - 10);
 107
 108         return ret;
 109 }
 110
 111 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
 112 {
 113         int max_sectors_kb = queue_max_sectors(q) >> 1;
 114
 115         return queue_var_show(max_sectors_kb, (page));
 116 }
 117
 118 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
 119 {
 120         return queue_var_show(queue_max_segments(q), (page));
 121 }
 122
 123 static ssize_t queue_max_discard_segments_show(struct request_queue *q,
 124                 char *page)
 125 {
 126         return queue_var_show(queue_max_discard_segments(q), (page));
 127 }
 128
 129 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
 130 {
 131         return queue_var_show(q->limits.max_integrity_segments, (page));
 132 }
 133
 134 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 135 {
 136         return queue_var_show(queue_max_segment_size(q), (page));
 137 }
 138
 139 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 140 {
 141         return queue_var_show(queue_logical_block_size(q), page);
 142 }
 143
 144 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 145 {
 146         return queue_var_show(queue_physical_block_size(q), page);
 147 }
 148
 149 static ssize_t queue_chunk_sectors_show(struct request_queue *q, char *page)
 150 {
 151         return queue_var_show(q->limits.chunk_sectors, page);
 152 }
 153
 154 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 155 {
 156         return queue_var_show(queue_io_min(q), page);
 157 }
 158
 159 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 160 {
 161         return queue_var_show(queue_io_opt(q), page);
 162 }
 163
 164 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 165 {
 166         return queue_var_show(q->limits.discard_granularity, page);
 167 }
 168
 169 static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
 170 {
 171
 172         return sprintf(page, "%llu\n",
 173                 (unsigned long long)q->limits.max_hw_discard_sectors << 9);
 174 }
 175
 176 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 177 {
 178         return sprintf(page, "%llu\n",
 179                        (unsigned long long)q->limits.max_discard_sectors << 9);
 180 }
 181
 182 static ssize_t queue_discard_max_store(struct request_queue *q,
 183                                        const char *page, size_t count)
 184 {
 185         unsigned long max_discard;
 186         ssize_t ret = queue_var_store(&max_discard, page, count);
 187
 188         if (ret < 0)
 189                 return ret;
 190
 191         if (max_discard & (q->limits.discard_granularity - 1))
 192                 return -EINVAL;
 193
 194         max_discard >>= 9;
 195         if (max_discard > UINT_MAX)
 196                 return -EINVAL;
 197
 198         if (max_discard > q->limits.max_hw_discard_sectors)
 199                 max_discard = q->limits.max_hw_discard_sectors;
 200
 201         q->limits.max_discard_sectors = max_discard;
 202         return ret;
 203 }
 204
 205 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 206 {
 207         return queue_var_show(0, page);
 208 }
 209
 210 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
 211 {
 212         return sprintf(page, "%llu\n",
 213                 (unsigned long long)q->limits.max_write_same_sectors << 9);
 214 }
 215
 216 static ssize_t queue_write_zeroes_max_show(struct request_queue *q, char *page)
 217 {
 218         return sprintf(page, "%llu\n",
 219                 (unsigned long long)q->limits.max_write_zeroes_sectors << 9);
 220 }
 221
 222 static ssize_t queue_zone_append_max_show(struct request_queue *q, char *page)
 223 {
 224         unsigned long long max_sectors = q->limits.max_zone_append_sectors;
 225
 226         return sprintf(page, "%llu\n", max_sectors << SECTOR_SHIFT);
 227 }
 228
 229 static ssize_t
 230 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 231 {
 232         unsigned long max_sectors_kb,
 233                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 234                         page_kb = 1 << (PAGE_SHIFT - 10);
 235         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 236
 237         if (ret < 0)
 238                 return ret;
 239
 240         max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, (unsigned long)
 241                                          q->limits.max_dev_sectors >> 1);
 242
 243         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 244                 return -EINVAL;
 245
 246         spin_lock_irq(&q->queue_lock);
 247         q->limits.max_sectors = max_sectors_kb << 1;
 248         q->backing_dev_info->io_pages = max_sectors_kb >> (PAGE_SHIFT - 10);
 249         spin_unlock_irq(&q->queue_lock);
 250
 251         return ret;
 252 }
 253
 254 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 255 {
 256         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 257
 258         return queue_var_show(max_hw_sectors_kb, (page));
 259 }
 260
 261 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 262 static ssize_t                                                          \
 263 queue_show_##name(struct request_queue *q, char *page)                  \
 264 {                                                                       \
 265         int bit;                                                        \
 266         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 267         return queue_var_show(neg ? !bit : bit, page);                  \
 268 }                                                                       \
 269 static ssize_t                                                          \
 270 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
 271 {                                                                       \
 272         unsigned long val;                                              \
 273         ssize_t ret;                                                    \
 274         ret = queue_var_store(&val, page, count);                       \
 275         if (ret < 0)                                                    \
 276                  return ret;                                            \
 277         if (neg)                                                        \
 278                 val = !val;                                             \
 279                                                                         \
 280         if (val)                                                        \
 281                 blk_queue_flag_set(QUEUE_FLAG_##flag, q);               \
 282         else                                                            \
 283                 blk_queue_flag_clear(QUEUE_FLAG_##flag, q);             \
 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_nr_zones_show(struct request_queue *q, char *page)
 305 {
 306         return queue_var_show(blk_queue_nr_zones(q), page);
 307 }
 308
 309 static ssize_t queue_max_open_zones_show(struct request_queue *q, char *page)
 310 {
 311         return queue_var_show(queue_max_open_zones(q), page);
 312 }
 313
 314 static ssize_t queue_max_active_zones_show(struct request_queue *q, char *page)
 315 {
 316         return queue_var_show(queue_max_active_zones(q), page);
 317 }
 318
 319 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 320 {
 321         return queue_var_show((blk_queue_nomerges(q) << 1) |
 322                                blk_queue_noxmerges(q), page);
 323 }
 324
 325 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 326                                     size_t count)
 327 {
 328         unsigned long nm;
 329         ssize_t ret = queue_var_store(&nm, page, count);
 330
 331         if (ret < 0)
 332                 return ret;
 333
 334         blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 335         blk_queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 336         if (nm == 2)
 337                 blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 338         else if (nm)
 339                 blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 340
 341         return ret;
 342 }
 343
 344 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 345 {
 346         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 347         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 348
 349         return queue_var_show(set << force, page);
 350 }
 351
 352 static ssize_t
 353 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 354 {
 355         ssize_t ret = -EINVAL;
 356 #ifdef CONFIG_SMP
 357         unsigned long val;
 358
 359         ret = queue_var_store(&val, page, count);
 360         if (ret < 0)
 361                 return ret;
 362
 363         if (val == 2) {
 364                 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 365                 blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 366         } else if (val == 1) {
 367                 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 368                 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 369         } else if (val == 0) {
 370                 blk_queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 371                 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 372         }
 373 #endif
 374         return ret;
 375 }
 376
 377 static ssize_t queue_poll_delay_show(struct request_queue *q, char *page)
 378 {
 379         int val;
 380
 381         if (q->poll_nsec == BLK_MQ_POLL_CLASSIC)
 382                 val = BLK_MQ_POLL_CLASSIC;
 383         else
 384                 val = q->poll_nsec / 1000;
 385
 386         return sprintf(page, "%d\n", val);
 387 }
 388
 389 static ssize_t queue_poll_delay_store(struct request_queue *q, const char *page,
 390                                 size_t count)
 391 {
 392         int err, val;
 393
 394         if (!q->mq_ops || !q->mq_ops->poll)
 395                 return -EINVAL;
 396
 397         err = kstrtoint(page, 10, &val);
 398         if (err < 0)
 399                 return err;
 400
 401         if (val == BLK_MQ_POLL_CLASSIC)
 402                 q->poll_nsec = BLK_MQ_POLL_CLASSIC;
 403         else if (val >= 0)
 404                 q->poll_nsec = val * 1000;
 405         else
 406                 return -EINVAL;
 407
 408         return count;
 409 }
 410
 411 static ssize_t queue_poll_show(struct request_queue *q, char *page)
 412 {
 413         return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
 414 }
 415
 416 static ssize_t queue_poll_store(struct request_queue *q, const char *page,
 417                                 size_t count)
 418 {
 419         unsigned long poll_on;
 420         ssize_t ret;
 421
 422         if (!q->tag_set || q->tag_set->nr_maps <= HCTX_TYPE_POLL ||
 423             !q->tag_set->map[HCTX_TYPE_POLL].nr_queues)
 424                 return -EINVAL;
 425
 426         ret = queue_var_store(&poll_on, page, count);
 427         if (ret < 0)
 428                 return ret;
 429
 430         if (poll_on)
 431                 blk_queue_flag_set(QUEUE_FLAG_POLL, q);
 432         else
 433                 blk_queue_flag_clear(QUEUE_FLAG_POLL, q);
 434
 435         return ret;
 436 }
 437
 438 static ssize_t queue_io_timeout_show(struct request_queue *q, char *page)
 439 {
 440         return sprintf(page, "%u\n", jiffies_to_msecs(q->rq_timeout));
 441 }
 442
 443 static ssize_t queue_io_timeout_store(struct request_queue *q, const char *page,
 444                                   size_t count)
 445 {
 446         unsigned int val;
 447         int err;
 448
 449         err = kstrtou32(page, 10, &val);
 450         if (err || val == 0)
 451                 return -EINVAL;
 452
 453         blk_queue_rq_timeout(q, msecs_to_jiffies(val));
 454
 455         return count;
 456 }
 457
 458 static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
 459 {
 460         if (!wbt_rq_qos(q))
 461                 return -EINVAL;
 462
 463         return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));
 464 }
 465
 466 static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
 467                                   size_t count)
 468 {
 469         struct rq_qos *rqos;
 470         ssize_t ret;
 471         s64 val;
 472
 473         ret = queue_var_store64(&val, page);
 474         if (ret < 0)
 475                 return ret;
 476         if (val < -1)
 477                 return -EINVAL;
 478
 479         rqos = wbt_rq_qos(q);
 480         if (!rqos) {
 481                 ret = wbt_init(q);
 482                 if (ret)
 483                         return ret;
 484         }
 485
 486         if (val == -1)
 487                 val = wbt_default_latency_nsec(q);
 488         else if (val >= 0)
 489                 val *= 1000ULL;
 490
 491         if (wbt_get_min_lat(q) == val)
 492                 return count;
 493
 494         /*
 495          * Ensure that the queue is idled, in case the latency update
 496          * ends up either enabling or disabling wbt completely. We can't
 497          * have IO inflight if that happens.
 498          */
 499         blk_mq_freeze_queue(q);
 500         blk_mq_quiesce_queue(q);
 501
 502         wbt_set_min_lat(q, val);
 503
 504         blk_mq_unquiesce_queue(q);
 505         blk_mq_unfreeze_queue(q);
 506
 507         return count;
 508 }
 509
 510 static ssize_t queue_wc_show(struct request_queue *q, char *page)
 511 {
 512         if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
 513                 return sprintf(page, "write back\n");
 514
 515         return sprintf(page, "write through\n");
 516 }
 517
 518 static ssize_t queue_wc_store(struct request_queue *q, const char *page,
 519                               size_t count)
 520 {
 521         int set = -1;
 522
 523         if (!strncmp(page, "write back", 10))
 524                 set = 1;
 525         else if (!strncmp(page, "write through", 13) ||
 526                  !strncmp(page, "none", 4))
 527                 set = 0;
 528
 529         if (set == -1)
 530                 return -EINVAL;
 531
 532         if (set)
 533                 blk_queue_flag_set(QUEUE_FLAG_WC, q);
 534         else
 535                 blk_queue_flag_clear(QUEUE_FLAG_WC, q);
 536
 537         return count;
 538 }
 539
 540 static ssize_t queue_fua_show(struct request_queue *q, char *page)
 541 {
 542         return sprintf(page, "%u\n", test_bit(QUEUE_FLAG_FUA, &q->queue_flags));
 543 }
 544
 545 static ssize_t queue_dax_show(struct request_queue *q, char *page)
 546 {
 547         return queue_var_show(blk_queue_dax(q), page);
 548 }
 549
 550 static struct queue_sysfs_entry queue_requests_entry = {
 551         .attr = {.name = "nr_requests", .mode = 0644 },
 552         .show = queue_requests_show,
 553         .store = queue_requests_store,
 554 };
 555
 556 static struct queue_sysfs_entry queue_ra_entry = {
 557         .attr = {.name = "read_ahead_kb", .mode = 0644 },
 558         .show = queue_ra_show,
 559         .store = queue_ra_store,
 560 };
 561
 562 static struct queue_sysfs_entry queue_max_sectors_entry = {
 563         .attr = {.name = "max_sectors_kb", .mode = 0644 },
 564         .show = queue_max_sectors_show,
 565         .store = queue_max_sectors_store,
 566 };
 567
 568 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 569         .attr = {.name = "max_hw_sectors_kb", .mode = 0444 },
 570         .show = queue_max_hw_sectors_show,
 571 };
 572
 573 static struct queue_sysfs_entry queue_max_segments_entry = {
 574         .attr = {.name = "max_segments", .mode = 0444 },
 575         .show = queue_max_segments_show,
 576 };
 577
 578 static struct queue_sysfs_entry queue_max_discard_segments_entry = {
 579         .attr = {.name = "max_discard_segments", .mode = 0444 },
 580         .show = queue_max_discard_segments_show,
 581 };
 582
 583 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
 584         .attr = {.name = "max_integrity_segments", .mode = 0444 },
 585         .show = queue_max_integrity_segments_show,
 586 };
 587
 588 static struct queue_sysfs_entry queue_max_segment_size_entry = {
 589         .attr = {.name = "max_segment_size", .mode = 0444 },
 590         .show = queue_max_segment_size_show,
 591 };
 592
 593 static struct queue_sysfs_entry queue_iosched_entry = {
 594         .attr = {.name = "scheduler", .mode = 0644 },
 595         .show = elv_iosched_show,
 596         .store = elv_iosched_store,
 597 };
 598
 599 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 600         .attr = {.name = "hw_sector_size", .mode = 0444 },
 601         .show = queue_logical_block_size_show,
 602 };
 603
 604 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 605         .attr = {.name = "logical_block_size", .mode = 0444 },
 606         .show = queue_logical_block_size_show,
 607 };
 608
 609 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 610         .attr = {.name = "physical_block_size", .mode = 0444 },
 611         .show = queue_physical_block_size_show,
 612 };
 613
 614 static struct queue_sysfs_entry queue_chunk_sectors_entry = {
 615         .attr = {.name = "chunk_sectors", .mode = 0444 },
 616         .show = queue_chunk_sectors_show,
 617 };
 618
 619 static struct queue_sysfs_entry queue_io_min_entry = {
 620         .attr = {.name = "minimum_io_size", .mode = 0444 },
 621         .show = queue_io_min_show,
 622 };
 623
 624 static struct queue_sysfs_entry queue_io_opt_entry = {
 625         .attr = {.name = "optimal_io_size", .mode = 0444 },
 626         .show = queue_io_opt_show,
 627 };
 628
 629 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 630         .attr = {.name = "discard_granularity", .mode = 0444 },
 631         .show = queue_discard_granularity_show,
 632 };
 633
 634 static struct queue_sysfs_entry queue_discard_max_hw_entry = {
 635         .attr = {.name = "discard_max_hw_bytes", .mode = 0444 },
 636         .show = queue_discard_max_hw_show,
 637 };
 638
 639 static struct queue_sysfs_entry queue_discard_max_entry = {
 640         .attr = {.name = "discard_max_bytes", .mode = 0644 },
 641         .show = queue_discard_max_show,
 642         .store = queue_discard_max_store,
 643 };
 644
 645 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 646         .attr = {.name = "discard_zeroes_data", .mode = 0444 },
 647         .show = queue_discard_zeroes_data_show,
 648 };
 649
 650 static struct queue_sysfs_entry queue_write_same_max_entry = {
 651         .attr = {.name = "write_same_max_bytes", .mode = 0444 },
 652         .show = queue_write_same_max_show,
 653 };
 654
 655 static struct queue_sysfs_entry queue_write_zeroes_max_entry = {
 656         .attr = {.name = "write_zeroes_max_bytes", .mode = 0444 },
 657         .show = queue_write_zeroes_max_show,
 658 };
 659
 660 static struct queue_sysfs_entry queue_zone_append_max_entry = {
 661         .attr = {.name = "zone_append_max_bytes", .mode = 0444 },
 662         .show = queue_zone_append_max_show,
 663 };
 664
 665 static struct queue_sysfs_entry queue_nonrot_entry = {
 666         .attr = {.name = "rotational", .mode = 0644 },
 667         .show = queue_show_nonrot,
 668         .store = queue_store_nonrot,
 669 };
 670
 671 static struct queue_sysfs_entry queue_zoned_entry = {
 672         .attr = {.name = "zoned", .mode = 0444 },
 673         .show = queue_zoned_show,
 674 };
 675
 676 static struct queue_sysfs_entry queue_nr_zones_entry = {
 677         .attr = {.name = "nr_zones", .mode = 0444 },
 678         .show = queue_nr_zones_show,
 679 };
 680
 681 static struct queue_sysfs_entry queue_max_open_zones_entry = {
 682         .attr = {.name = "max_open_zones", .mode = 0444 },
 683         .show = queue_max_open_zones_show,
 684 };
 685
 686 static struct queue_sysfs_entry queue_max_active_zones_entry = {
 687         .attr = {.name = "max_active_zones", .mode = 0444 },
 688         .show = queue_max_active_zones_show,
 689 };
 690
 691 static struct queue_sysfs_entry queue_nomerges_entry = {
 692         .attr = {.name = "nomerges", .mode = 0644 },
 693         .show = queue_nomerges_show,
 694         .store = queue_nomerges_store,
 695 };
 696
 697 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 698         .attr = {.name = "rq_affinity", .mode = 0644 },
 699         .show = queue_rq_affinity_show,
 700         .store = queue_rq_affinity_store,
 701 };
 702
 703 static struct queue_sysfs_entry queue_iostats_entry = {
 704         .attr = {.name = "iostats", .mode = 0644 },
 705         .show = queue_show_iostats,
 706         .store = queue_store_iostats,
 707 };
 708
 709 static struct queue_sysfs_entry queue_random_entry = {
 710         .attr = {.name = "add_random", .mode = 0644 },
 711         .show = queue_show_random,
 712         .store = queue_store_random,
 713 };
 714
 715 static struct queue_sysfs_entry queue_poll_entry = {
 716         .attr = {.name = "io_poll", .mode = 0644 },
 717         .show = queue_poll_show,
 718         .store = queue_poll_store,
 719 };
 720
 721 static struct queue_sysfs_entry queue_poll_delay_entry = {
 722         .attr = {.name = "io_poll_delay", .mode = 0644 },
 723         .show = queue_poll_delay_show,
 724         .store = queue_poll_delay_store,
 725 };
 726
 727 static struct queue_sysfs_entry queue_wc_entry = {
 728         .attr = {.name = "write_cache", .mode = 0644 },
 729         .show = queue_wc_show,
 730         .store = queue_wc_store,
 731 };
 732
 733 static struct queue_sysfs_entry queue_fua_entry = {
 734         .attr = {.name = "fua", .mode = 0444 },
 735         .show = queue_fua_show,
 736 };
 737
 738 static struct queue_sysfs_entry queue_dax_entry = {
 739         .attr = {.name = "dax", .mode = 0444 },
 740         .show = queue_dax_show,
 741 };
 742
 743 static struct queue_sysfs_entry queue_io_timeout_entry = {
 744         .attr = {.name = "io_timeout", .mode = 0644 },
 745         .show = queue_io_timeout_show,
 746         .store = queue_io_timeout_store,
 747 };
 748
 749 static struct queue_sysfs_entry queue_wb_lat_entry = {
 750         .attr = {.name = "wbt_lat_usec", .mode = 0644 },
 751         .show = queue_wb_lat_show,
 752         .store = queue_wb_lat_store,
 753 };
 754
 755 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 756 static struct queue_sysfs_entry throtl_sample_time_entry = {
 757         .attr = {.name = "throttle_sample_time", .mode = 0644 },
 758         .show = blk_throtl_sample_time_show,
 759         .store = blk_throtl_sample_time_store,
 760 };
 761 #endif
 762
 763 static struct attribute *queue_attrs[] = {
 764         &queue_requests_entry.attr,
 765         &queue_ra_entry.attr,
 766         &queue_max_hw_sectors_entry.attr,
 767         &queue_max_sectors_entry.attr,
 768         &queue_max_segments_entry.attr,
 769         &queue_max_discard_segments_entry.attr,
 770         &queue_max_integrity_segments_entry.attr,
 771         &queue_max_segment_size_entry.attr,
 772         &queue_iosched_entry.attr,
 773         &queue_hw_sector_size_entry.attr,
 774         &queue_logical_block_size_entry.attr,
 775         &queue_physical_block_size_entry.attr,
 776         &queue_chunk_sectors_entry.attr,
 777         &queue_io_min_entry.attr,
 778         &queue_io_opt_entry.attr,
 779         &queue_discard_granularity_entry.attr,
 780         &queue_discard_max_entry.attr,
 781         &queue_discard_max_hw_entry.attr,
 782         &queue_discard_zeroes_data_entry.attr,
 783         &queue_write_same_max_entry.attr,
 784         &queue_write_zeroes_max_entry.attr,
 785         &queue_zone_append_max_entry.attr,
 786         &queue_nonrot_entry.attr,
 787         &queue_zoned_entry.attr,
 788         &queue_nr_zones_entry.attr,
 789         &queue_max_open_zones_entry.attr,
 790         &queue_max_active_zones_entry.attr,
 791         &queue_nomerges_entry.attr,
 792         &queue_rq_affinity_entry.attr,
 793         &queue_iostats_entry.attr,
 794         &queue_random_entry.attr,
 795         &queue_poll_entry.attr,
 796         &queue_wc_entry.attr,
 797         &queue_fua_entry.attr,
 798         &queue_dax_entry.attr,
 799         &queue_wb_lat_entry.attr,
 800         &queue_poll_delay_entry.attr,
 801         &queue_io_timeout_entry.attr,
 802 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 803         &throtl_sample_time_entry.attr,
 804 #endif
 805         NULL,
 806 };
 807
 808 static umode_t queue_attr_visible(struct kobject *kobj, struct attribute *attr,
 809                                 int n)
 810 {
 811         struct request_queue *q =
 812                 container_of(kobj, struct request_queue, kobj);
 813
 814         if (attr == &queue_io_timeout_entry.attr &&
 815                 (!q->mq_ops || !q->mq_ops->timeout))
 816                         return 0;
 817
 818         if ((attr == &queue_max_open_zones_entry.attr ||
 819              attr == &queue_max_active_zones_entry.attr) &&
 820             !blk_queue_is_zoned(q))
 821                 return 0;
 822
 823         return attr->mode;
 824 }
 825
 826 static struct attribute_group queue_attr_group = {
 827         .attrs = queue_attrs,
 828         .is_visible = queue_attr_visible,
 829 };
 830
 831
 832 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 833
 834 static ssize_t
 835 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 836 {
 837         struct queue_sysfs_entry *entry = to_queue(attr);
 838         struct request_queue *q =
 839                 container_of(kobj, struct request_queue, kobj);
 840         ssize_t res;
 841
 842         if (!entry->show)
 843                 return -EIO;
 844         mutex_lock(&q->sysfs_lock);
 845         res = entry->show(q, page);
 846         mutex_unlock(&q->sysfs_lock);
 847         return res;
 848 }
 849
 850 static ssize_t
 851 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 852                     const char *page, size_t length)
 853 {
 854         struct queue_sysfs_entry *entry = to_queue(attr);
 855         struct request_queue *q;
 856         ssize_t res;
 857
 858         if (!entry->store)
 859                 return -EIO;
 860
 861         q = container_of(kobj, struct request_queue, kobj);
 862         mutex_lock(&q->sysfs_lock);
 863         res = entry->store(q, page, length);
 864         mutex_unlock(&q->sysfs_lock);
 865         return res;
 866 }
 867
 868 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 869 {
 870         struct request_queue *q = container_of(rcu_head, struct request_queue,
 871                                                rcu_head);
 872         kmem_cache_free(blk_requestq_cachep, q);
 873 }
 874
 875 /* Unconfigure the I/O scheduler and dissociate from the cgroup controller. */
 876 static void blk_exit_queue(struct request_queue *q)
 877 {
 878         /*
 879          * Since the I/O scheduler exit code may access cgroup information,
 880          * perform I/O scheduler exit before disassociating from the block
 881          * cgroup controller.
 882          */
 883         if (q->elevator) {
 884                 ioc_clear_queue(q);
 885                 __elevator_exit(q, q->elevator);
 886                 q->elevator = NULL;
 887         }
 888
 889         /*
 890          * Remove all references to @q from the block cgroup controller before
 891          * restoring @q->queue_lock to avoid that restoring this pointer causes
 892          * e.g. blkcg_print_blkgs() to crash.
 893          */
 894         blkcg_exit_queue(q);
 895
 896         /*
 897          * Since the cgroup code may dereference the @q->backing_dev_info
 898          * pointer, only decrease its reference count after having removed the
 899          * association with the block cgroup controller.
 900          */
 901         bdi_put(q->backing_dev_info);
 902 }
 903
 904 /**
 905  * blk_release_queue - releases all allocated resources of the request_queue
 906  * @kobj: pointer to a kobject, whose container is a request_queue
 907  *
 908  * This function releases all allocated resources of the request queue.
 909  *
 910  * The struct request_queue refcount is incremented with blk_get_queue() and
 911  * decremented with blk_put_queue(). Once the refcount reaches 0 this function
 912  * is called.
 913  *
 914  * For drivers that have a request_queue on a gendisk and added with
 915  * __device_add_disk() the refcount to request_queue will reach 0 with
 916  * the last put_disk() called by the driver. For drivers which don't use
 917  * __device_add_disk() this happens with blk_cleanup_queue().
 918  *
 919  * Drivers exist which depend on the release of the request_queue to be
 920  * synchronous, it should not be deferred.
 921  *
 922  * Context: can sleep
 923  */
 924 static void blk_release_queue(struct kobject *kobj)
 925 {
 926         struct request_queue *q =
 927                 container_of(kobj, struct request_queue, kobj);
 928
 929         might_sleep();
 930
 931         if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags))
 932                 blk_stat_remove_callback(q, q->poll_cb);
 933         blk_stat_free_callback(q->poll_cb);
 934
 935         blk_free_queue_stats(q->stats);
 936
 937         if (queue_is_mq(q))
 938                 cancel_delayed_work_sync(&q->requeue_work);
 939
 940         blk_exit_queue(q);
 941
 942         blk_queue_free_zone_bitmaps(q);
 943
 944         if (queue_is_mq(q))
 945                 blk_mq_release(q);
 946
 947         blk_trace_shutdown(q);
 948         mutex_lock(&q->debugfs_mutex);
 949         debugfs_remove_recursive(q->debugfs_dir);
 950         mutex_unlock(&q->debugfs_mutex);
 951
 952         if (queue_is_mq(q))
 953                 blk_mq_debugfs_unregister(q);
 954
 955         bioset_exit(&q->bio_split);
 956
 957         ida_simple_remove(&blk_queue_ida, q->id);
 958         call_rcu(&q->rcu_head, blk_free_queue_rcu);
 959 }
 960
 961 static const struct sysfs_ops queue_sysfs_ops = {
 962         .show   = queue_attr_show,
 963         .store  = queue_attr_store,
 964 };
 965
 966 struct kobj_type blk_queue_ktype = {
 967         .sysfs_ops      = &queue_sysfs_ops,
 968         .release        = blk_release_queue,
 969 };
 970
 971 /**
 972  * blk_register_queue - register a block layer queue with sysfs
 973  * @disk: Disk of which the request queue should be registered with sysfs.
 974  */
 975 int blk_register_queue(struct gendisk *disk)
 976 {
 977         int ret;
 978         struct device *dev = disk_to_dev(disk);
 979         struct request_queue *q = disk->queue;
 980         bool has_elevator = false;
 981
 982         if (WARN_ON(!q))
 983                 return -ENXIO;
 984
 985         WARN_ONCE(blk_queue_registered(q),
 986                   "%s is registering an already registered queue\n",
 987                   kobject_name(&dev->kobj));
 988
 989         /*
 990          * SCSI probing may synchronously create and destroy a lot of
 991          * request_queues for non-existent devices.  Shutting down a fully
 992          * functional queue takes measureable wallclock time as RCU grace
 993          * periods are involved.  To avoid excessive latency in these
 994          * cases, a request_queue starts out in a degraded mode which is
 995          * faster to shut down and is made fully functional here as
 996          * request_queues for non-existent devices never get registered.
 997          */
 998         if (!blk_queue_init_done(q)) {
 999                 blk_queue_flag_set(QUEUE_FLAG_INIT_DONE, q);
1000                 percpu_ref_switch_to_percpu(&q->q_usage_counter);
1001         }
1002
1003         ret = blk_trace_init_sysfs(dev);
1004         if (ret)
1005                 return ret;
1006
1007         mutex_lock(&q->sysfs_dir_lock);
1008
1009         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
1010         if (ret < 0) {
1011                 blk_trace_remove_sysfs(dev);
1012                 goto unlock;
1013         }
1014
1015         ret = sysfs_create_group(&q->kobj, &queue_attr_group);
1016         if (ret) {
1017                 blk_trace_remove_sysfs(dev);
1018                 kobject_del(&q->kobj);
1019                 kobject_put(&dev->kobj);
1020                 goto unlock;
1021         }
1022
1023         mutex_lock(&q->debugfs_mutex);
1024         q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
1025                                             blk_debugfs_root);
1026         mutex_unlock(&q->debugfs_mutex);
1027
1028         if (queue_is_mq(q)) {
1029                 __blk_mq_register_dev(dev, q);
1030                 blk_mq_debugfs_register(q);
1031         }
1032
1033         mutex_lock(&q->sysfs_lock);
1034         if (q->elevator) {
1035                 ret = elv_register_queue(q, false);
1036                 if (ret) {
1037                         mutex_unlock(&q->sysfs_lock);
1038                         mutex_unlock(&q->sysfs_dir_lock);
1039                         kobject_del(&q->kobj);
1040                         blk_trace_remove_sysfs(dev);
1041                         kobject_put(&dev->kobj);
1042                         return ret;
1043                 }
1044                 has_elevator = true;
1045         }
1046
1047         blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);
1048         wbt_enable_default(q);
1049         blk_throtl_register_queue(q);
1050
1051         /* Now everything is ready and send out KOBJ_ADD uevent */
1052         kobject_uevent(&q->kobj, KOBJ_ADD);
1053         if (has_elevator)
1054                 kobject_uevent(&q->elevator->kobj, KOBJ_ADD);
1055         mutex_unlock(&q->sysfs_lock);
1056
1057         ret = 0;
1058 unlock:
1059         mutex_unlock(&q->sysfs_dir_lock);
1060         return ret;
1061 }
1062 EXPORT_SYMBOL_GPL(blk_register_queue);
1063
1064 /**
1065  * blk_unregister_queue - counterpart of blk_register_queue()
1066  * @disk: Disk of which the request queue should be unregistered from sysfs.
1067  *
1068  * Note: the caller is responsible for guaranteeing that this function is called
1069  * after blk_register_queue() has finished.
1070  */
1071 void blk_unregister_queue(struct gendisk *disk)
1072 {
1073         struct request_queue *q = disk->queue;
1074
1075         if (WARN_ON(!q))
1076                 return;
1077
1078         /* Return early if disk->queue was never registered. */
1079         if (!blk_queue_registered(q))
1080                 return;
1081
1082         /*
1083          * Since sysfs_remove_dir() prevents adding new directory entries
1084          * before removal of existing entries starts, protect against
1085          * concurrent elv_iosched_store() calls.
1086          */
1087         mutex_lock(&q->sysfs_lock);
1088         blk_queue_flag_clear(QUEUE_FLAG_REGISTERED, q);
1089         mutex_unlock(&q->sysfs_lock);
1090
1091         mutex_lock(&q->sysfs_dir_lock);
1092         /*
1093          * Remove the sysfs attributes before unregistering the queue data
1094          * structures that can be modified through sysfs.
1095          */
1096         if (queue_is_mq(q))
1097                 blk_mq_unregister_dev(disk_to_dev(disk), q);
1098
1099         kobject_uevent(&q->kobj, KOBJ_REMOVE);
1100         kobject_del(&q->kobj);
1101         blk_trace_remove_sysfs(disk_to_dev(disk));
1102
1103         mutex_lock(&q->sysfs_lock);
1104         if (q->elevator)
1105                 elv_unregister_queue(q);
1106         mutex_unlock(&q->sysfs_lock);
1107         mutex_unlock(&q->sysfs_dir_lock);
1108
1109         kobject_put(&disk_to_dev(disk)->kobj);
1110 }