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