linux/block/blk-sysfs.c
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   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/blktrace_api.h>
  10
  11#include "blk.h"
  12#include "blk-cgroup.h"
  13
  14struct queue_sysfs_entry {
  15        struct attribute attr;
  16        ssize_t (*show)(struct request_queue *, char *);
  17        ssize_t (*store)(struct request_queue *, const char *, size_t);
  18};
  19
  20static ssize_t
  21queue_var_show(unsigned long var, char *page)
  22{
  23        return sprintf(page, "%lu\n", var);
  24}
  25
  26static ssize_t
  27queue_var_store(unsigned long *var, const char *page, size_t count)
  28{
  29        int err;
  30        unsigned long v;
  31
  32        err = strict_strtoul(page, 10, &v);
  33        if (err || v > UINT_MAX)
  34                return -EINVAL;
  35
  36        *var = v;
  37
  38        return count;
  39}
  40
  41static ssize_t queue_requests_show(struct request_queue *q, char *page)
  42{
  43        return queue_var_show(q->nr_requests, (page));
  44}
  45
  46static ssize_t
  47queue_requests_store(struct request_queue *q, const char *page, size_t count)
  48{
  49        struct request_list *rl;
  50        unsigned long nr;
  51        int ret;
  52
  53        if (!q->request_fn)
  54                return -EINVAL;
  55
  56        ret = queue_var_store(&nr, page, count);
  57        if (ret < 0)
  58                return ret;
  59
  60        if (nr < BLKDEV_MIN_RQ)
  61                nr = BLKDEV_MIN_RQ;
  62
  63        spin_lock_irq(q->queue_lock);
  64        q->nr_requests = nr;
  65        blk_queue_congestion_threshold(q);
  66
  67        /* congestion isn't cgroup aware and follows root blkcg for now */
  68        rl = &q->root_rl;
  69
  70        if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
  71                blk_set_queue_congested(q, BLK_RW_SYNC);
  72        else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
  73                blk_clear_queue_congested(q, BLK_RW_SYNC);
  74
  75        if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
  76                blk_set_queue_congested(q, BLK_RW_ASYNC);
  77        else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
  78                blk_clear_queue_congested(q, BLK_RW_ASYNC);
  79
  80        blk_queue_for_each_rl(rl, q) {
  81                if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
  82                        blk_set_rl_full(rl, BLK_RW_SYNC);
  83                } else {
  84                        blk_clear_rl_full(rl, BLK_RW_SYNC);
  85                        wake_up(&rl->wait[BLK_RW_SYNC]);
  86                }
  87
  88                if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
  89                        blk_set_rl_full(rl, BLK_RW_ASYNC);
  90                } else {
  91                        blk_clear_rl_full(rl, BLK_RW_ASYNC);
  92                        wake_up(&rl->wait[BLK_RW_ASYNC]);
  93                }
  94        }
  95
  96        spin_unlock_irq(q->queue_lock);
  97        return ret;
  98}
  99
 100static ssize_t queue_ra_show(struct request_queue *q, char *page)
 101{
 102        unsigned long ra_kb = q->backing_dev_info.ra_pages <<
 103                                        (PAGE_CACHE_SHIFT - 10);
 104
 105        return queue_var_show(ra_kb, (page));
 106}
 107
 108static ssize_t
 109queue_ra_store(struct request_queue *q, const char *page, size_t count)
 110{
 111        unsigned long ra_kb;
 112        ssize_t ret = queue_var_store(&ra_kb, page, count);
 113
 114        if (ret < 0)
 115                return ret;
 116
 117        q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
 118
 119        return ret;
 120}
 121
 122static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
 123{
 124        int max_sectors_kb = queue_max_sectors(q) >> 1;
 125
 126        return queue_var_show(max_sectors_kb, (page));
 127}
 128
 129static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
 130{
 131        return queue_var_show(queue_max_segments(q), (page));
 132}
 133
 134static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
 135{
 136        return queue_var_show(q->limits.max_integrity_segments, (page));
 137}
 138
 139static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 140{
 141        if (blk_queue_cluster(q))
 142                return queue_var_show(queue_max_segment_size(q), (page));
 143
 144        return queue_var_show(PAGE_CACHE_SIZE, (page));
 145}
 146
 147static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 148{
 149        return queue_var_show(queue_logical_block_size(q), page);
 150}
 151
 152static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 153{
 154        return queue_var_show(queue_physical_block_size(q), page);
 155}
 156
 157static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 158{
 159        return queue_var_show(queue_io_min(q), page);
 160}
 161
 162static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 163{
 164        return queue_var_show(queue_io_opt(q), page);
 165}
 166
 167static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 168{
 169        return queue_var_show(q->limits.discard_granularity, page);
 170}
 171
 172static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 173{
 174        return sprintf(page, "%llu\n",
 175                       (unsigned long long)q->limits.max_discard_sectors << 9);
 176}
 177
 178static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 179{
 180        return queue_var_show(queue_discard_zeroes_data(q), page);
 181}
 182
 183static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
 184{
 185        return sprintf(page, "%llu\n",
 186                (unsigned long long)q->limits.max_write_same_sectors << 9);
 187}
 188
 189
 190static ssize_t
 191queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 192{
 193        unsigned long max_sectors_kb,
 194                max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 195                        page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
 196        ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 197
 198        if (ret < 0)
 199                return ret;
 200
 201        if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 202                return -EINVAL;
 203
 204        spin_lock_irq(q->queue_lock);
 205        q->limits.max_sectors = max_sectors_kb << 1;
 206        spin_unlock_irq(q->queue_lock);
 207
 208        return ret;
 209}
 210
 211static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 212{
 213        int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 214
 215        return queue_var_show(max_hw_sectors_kb, (page));
 216}
 217
 218#define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 219static ssize_t                                                          \
 220queue_show_##name(struct request_queue *q, char *page)                  \
 221{                                                                       \
 222        int bit;                                                        \
 223        bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 224        return queue_var_show(neg ? !bit : bit, page);                  \
 225}                                                                       \
 226static ssize_t                                                          \
 227queue_store_##name(struct request_queue *q, const char *page, size_t count) \
 228{                                                                       \
 229        unsigned long val;                                              \
 230        ssize_t ret;                                                    \
 231        ret = queue_var_store(&val, page, count);                       \
 232        if (ret < 0)                                                    \
 233                 return ret;                                            \
 234        if (neg)                                                        \
 235                val = !val;                                             \
 236                                                                        \
 237        spin_lock_irq(q->queue_lock);                                   \
 238        if (val)                                                        \
 239                queue_flag_set(QUEUE_FLAG_##flag, q);                   \
 240        else                                                            \
 241                queue_flag_clear(QUEUE_FLAG_##flag, q);                 \
 242        spin_unlock_irq(q->queue_lock);                                 \
 243        return ret;                                                     \
 244}
 245
 246QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 247QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 248QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 249#undef QUEUE_SYSFS_BIT_FNS
 250
 251static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 252{
 253        return queue_var_show((blk_queue_nomerges(q) << 1) |
 254                               blk_queue_noxmerges(q), page);
 255}
 256
 257static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 258                                    size_t count)
 259{
 260        unsigned long nm;
 261        ssize_t ret = queue_var_store(&nm, page, count);
 262
 263        if (ret < 0)
 264                return ret;
 265
 266        spin_lock_irq(q->queue_lock);
 267        queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 268        queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 269        if (nm == 2)
 270                queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 271        else if (nm)
 272                queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 273        spin_unlock_irq(q->queue_lock);
 274
 275        return ret;
 276}
 277
 278static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 279{
 280        bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 281        bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 282
 283        return queue_var_show(set << force, page);
 284}
 285
 286static ssize_t
 287queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 288{
 289        ssize_t ret = -EINVAL;
 290#if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
 291        unsigned long val;
 292
 293        ret = queue_var_store(&val, page, count);
 294        if (ret < 0)
 295                return ret;
 296
 297        spin_lock_irq(q->queue_lock);
 298        if (val == 2) {
 299                queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 300                queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 301        } else if (val == 1) {
 302                queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 303                queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 304        } else if (val == 0) {
 305                queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 306                queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 307        }
 308        spin_unlock_irq(q->queue_lock);
 309#endif
 310        return ret;
 311}
 312
 313static struct queue_sysfs_entry queue_requests_entry = {
 314        .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 315        .show = queue_requests_show,
 316        .store = queue_requests_store,
 317};
 318
 319static struct queue_sysfs_entry queue_ra_entry = {
 320        .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 321        .show = queue_ra_show,
 322        .store = queue_ra_store,
 323};
 324
 325static struct queue_sysfs_entry queue_max_sectors_entry = {
 326        .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 327        .show = queue_max_sectors_show,
 328        .store = queue_max_sectors_store,
 329};
 330
 331static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 332        .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 333        .show = queue_max_hw_sectors_show,
 334};
 335
 336static struct queue_sysfs_entry queue_max_segments_entry = {
 337        .attr = {.name = "max_segments", .mode = S_IRUGO },
 338        .show = queue_max_segments_show,
 339};
 340
 341static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
 342        .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
 343        .show = queue_max_integrity_segments_show,
 344};
 345
 346static struct queue_sysfs_entry queue_max_segment_size_entry = {
 347        .attr = {.name = "max_segment_size", .mode = S_IRUGO },
 348        .show = queue_max_segment_size_show,
 349};
 350
 351static struct queue_sysfs_entry queue_iosched_entry = {
 352        .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 353        .show = elv_iosched_show,
 354        .store = elv_iosched_store,
 355};
 356
 357static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 358        .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 359        .show = queue_logical_block_size_show,
 360};
 361
 362static struct queue_sysfs_entry queue_logical_block_size_entry = {
 363        .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 364        .show = queue_logical_block_size_show,
 365};
 366
 367static struct queue_sysfs_entry queue_physical_block_size_entry = {
 368        .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 369        .show = queue_physical_block_size_show,
 370};
 371
 372static struct queue_sysfs_entry queue_io_min_entry = {
 373        .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 374        .show = queue_io_min_show,
 375};
 376
 377static struct queue_sysfs_entry queue_io_opt_entry = {
 378        .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 379        .show = queue_io_opt_show,
 380};
 381
 382static struct queue_sysfs_entry queue_discard_granularity_entry = {
 383        .attr = {.name = "discard_granularity", .mode = S_IRUGO },
 384        .show = queue_discard_granularity_show,
 385};
 386
 387static struct queue_sysfs_entry queue_discard_max_entry = {
 388        .attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
 389        .show = queue_discard_max_show,
 390};
 391
 392static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 393        .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
 394        .show = queue_discard_zeroes_data_show,
 395};
 396
 397static struct queue_sysfs_entry queue_write_same_max_entry = {
 398        .attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
 399        .show = queue_write_same_max_show,
 400};
 401
 402static struct queue_sysfs_entry queue_nonrot_entry = {
 403        .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 404        .show = queue_show_nonrot,
 405        .store = queue_store_nonrot,
 406};
 407
 408static struct queue_sysfs_entry queue_nomerges_entry = {
 409        .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 410        .show = queue_nomerges_show,
 411        .store = queue_nomerges_store,
 412};
 413
 414static struct queue_sysfs_entry queue_rq_affinity_entry = {
 415        .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 416        .show = queue_rq_affinity_show,
 417        .store = queue_rq_affinity_store,
 418};
 419
 420static struct queue_sysfs_entry queue_iostats_entry = {
 421        .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 422        .show = queue_show_iostats,
 423        .store = queue_store_iostats,
 424};
 425
 426static struct queue_sysfs_entry queue_random_entry = {
 427        .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
 428        .show = queue_show_random,
 429        .store = queue_store_random,
 430};
 431
 432static struct attribute *default_attrs[] = {
 433        &queue_requests_entry.attr,
 434        &queue_ra_entry.attr,
 435        &queue_max_hw_sectors_entry.attr,
 436        &queue_max_sectors_entry.attr,
 437        &queue_max_segments_entry.attr,
 438        &queue_max_integrity_segments_entry.attr,
 439        &queue_max_segment_size_entry.attr,
 440        &queue_iosched_entry.attr,
 441        &queue_hw_sector_size_entry.attr,
 442        &queue_logical_block_size_entry.attr,
 443        &queue_physical_block_size_entry.attr,
 444        &queue_io_min_entry.attr,
 445        &queue_io_opt_entry.attr,
 446        &queue_discard_granularity_entry.attr,
 447        &queue_discard_max_entry.attr,
 448        &queue_discard_zeroes_data_entry.attr,
 449        &queue_write_same_max_entry.attr,
 450        &queue_nonrot_entry.attr,
 451        &queue_nomerges_entry.attr,
 452        &queue_rq_affinity_entry.attr,
 453        &queue_iostats_entry.attr,
 454        &queue_random_entry.attr,
 455        NULL,
 456};
 457
 458#define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 459
 460static ssize_t
 461queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 462{
 463        struct queue_sysfs_entry *entry = to_queue(attr);
 464        struct request_queue *q =
 465                container_of(kobj, struct request_queue, kobj);
 466        ssize_t res;
 467
 468        if (!entry->show)
 469                return -EIO;
 470        mutex_lock(&q->sysfs_lock);
 471        if (blk_queue_dying(q)) {
 472                mutex_unlock(&q->sysfs_lock);
 473                return -ENOENT;
 474        }
 475        res = entry->show(q, page);
 476        mutex_unlock(&q->sysfs_lock);
 477        return res;
 478}
 479
 480static ssize_t
 481queue_attr_store(struct kobject *kobj, struct attribute *attr,
 482                    const char *page, size_t length)
 483{
 484        struct queue_sysfs_entry *entry = to_queue(attr);
 485        struct request_queue *q;
 486        ssize_t res;
 487
 488        if (!entry->store)
 489                return -EIO;
 490
 491        q = container_of(kobj, struct request_queue, kobj);
 492        mutex_lock(&q->sysfs_lock);
 493        if (blk_queue_dying(q)) {
 494                mutex_unlock(&q->sysfs_lock);
 495                return -ENOENT;
 496        }
 497        res = entry->store(q, page, length);
 498        mutex_unlock(&q->sysfs_lock);
 499        return res;
 500}
 501
 502static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 503{
 504        struct request_queue *q = container_of(rcu_head, struct request_queue,
 505                                               rcu_head);
 506        kmem_cache_free(blk_requestq_cachep, q);
 507}
 508
 509/**
 510 * blk_release_queue: - release a &struct request_queue when it is no longer needed
 511 * @kobj:    the kobj belonging to the request queue to be released
 512 *
 513 * Description:
 514 *     blk_release_queue is the pair to blk_init_queue() or
 515 *     blk_queue_make_request().  It should be called when a request queue is
 516 *     being released; typically when a block device is being de-registered.
 517 *     Currently, its primary task it to free all the &struct request
 518 *     structures that were allocated to the queue and the queue itself.
 519 *
 520 * Caveat:
 521 *     Hopefully the low level driver will have finished any
 522 *     outstanding requests first...
 523 **/
 524static void blk_release_queue(struct kobject *kobj)
 525{
 526        struct request_queue *q =
 527                container_of(kobj, struct request_queue, kobj);
 528
 529        blk_sync_queue(q);
 530
 531        blkcg_exit_queue(q);
 532
 533        if (q->elevator) {
 534                spin_lock_irq(q->queue_lock);
 535                ioc_clear_queue(q);
 536                spin_unlock_irq(q->queue_lock);
 537                elevator_exit(q->elevator);
 538        }
 539
 540        blk_exit_rl(&q->root_rl);
 541
 542        if (q->queue_tags)
 543                __blk_queue_free_tags(q);
 544
 545        blk_trace_shutdown(q);
 546
 547        bdi_destroy(&q->backing_dev_info);
 548
 549        ida_simple_remove(&blk_queue_ida, q->id);
 550        call_rcu(&q->rcu_head, blk_free_queue_rcu);
 551}
 552
 553static const struct sysfs_ops queue_sysfs_ops = {
 554        .show   = queue_attr_show,
 555        .store  = queue_attr_store,
 556};
 557
 558struct kobj_type blk_queue_ktype = {
 559        .sysfs_ops      = &queue_sysfs_ops,
 560        .default_attrs  = default_attrs,
 561        .release        = blk_release_queue,
 562};
 563
 564int blk_register_queue(struct gendisk *disk)
 565{
 566        int ret;
 567        struct device *dev = disk_to_dev(disk);
 568        struct request_queue *q = disk->queue;
 569
 570        if (WARN_ON(!q))
 571                return -ENXIO;
 572
 573        /*
 574         * Initialization must be complete by now.  Finish the initial
 575         * bypass from queue allocation.
 576         */
 577        blk_queue_bypass_end(q);
 578
 579        ret = blk_trace_init_sysfs(dev);
 580        if (ret)
 581                return ret;
 582
 583        ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 584        if (ret < 0) {
 585                blk_trace_remove_sysfs(dev);
 586                return ret;
 587        }
 588
 589        kobject_uevent(&q->kobj, KOBJ_ADD);
 590
 591        if (!q->request_fn)
 592                return 0;
 593
 594        ret = elv_register_queue(q);
 595        if (ret) {
 596                kobject_uevent(&q->kobj, KOBJ_REMOVE);
 597                kobject_del(&q->kobj);
 598                blk_trace_remove_sysfs(dev);
 599                kobject_put(&dev->kobj);
 600                return ret;
 601        }
 602
 603        return 0;
 604}
 605
 606void blk_unregister_queue(struct gendisk *disk)
 607{
 608        struct request_queue *q = disk->queue;
 609
 610        if (WARN_ON(!q))
 611                return;
 612
 613        if (q->request_fn)
 614                elv_unregister_queue(q);
 615
 616        kobject_uevent(&q->kobj, KOBJ_REMOVE);
 617        kobject_del(&q->kobj);
 618        blk_trace_remove_sysfs(disk_to_dev(disk));
 619        kobject_put(&disk_to_dev(disk)->kobj);
 620}
 621
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