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