linux/block/blk-sysfs.c
<<
>>
Prefs
   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;
  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        /* congestion isn't cgroup aware and follows root blkcg for now */
  59        rl = &q->root_rl;
  60
  61        if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
  62                blk_set_queue_congested(q, BLK_RW_SYNC);
  63        else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
  64                blk_clear_queue_congested(q, BLK_RW_SYNC);
  65
  66        if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
  67                blk_set_queue_congested(q, BLK_RW_ASYNC);
  68        else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
  69                blk_clear_queue_congested(q, BLK_RW_ASYNC);
  70
  71        blk_queue_for_each_rl(rl, q) {
  72                if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
  73                        blk_set_rl_full(rl, BLK_RW_SYNC);
  74                } else {
  75                        blk_clear_rl_full(rl, BLK_RW_SYNC);
  76                        wake_up(&rl->wait[BLK_RW_SYNC]);
  77                }
  78
  79                if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
  80                        blk_set_rl_full(rl, BLK_RW_ASYNC);
  81                } else {
  82                        blk_clear_rl_full(rl, BLK_RW_ASYNC);
  83                        wake_up(&rl->wait[BLK_RW_ASYNC]);
  84                }
  85        }
  86
  87        spin_unlock_irq(q->queue_lock);
  88        return ret;
  89}
  90
  91static ssize_t queue_ra_show(struct request_queue *q, char *page)
  92{
  93        unsigned long ra_kb = q->backing_dev_info.ra_pages <<
  94                                        (PAGE_CACHE_SHIFT - 10);
  95
  96        return queue_var_show(ra_kb, (page));
  97}
  98
  99static ssize_t
 100queue_ra_store(struct request_queue *q, const char *page, size_t count)
 101{
 102        unsigned long ra_kb;
 103        ssize_t ret = queue_var_store(&ra_kb, page, count);
 104
 105        q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
 106
 107        return ret;
 108}
 109
 110static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
 111{
 112        int max_sectors_kb = queue_max_sectors(q) >> 1;
 113
 114        return queue_var_show(max_sectors_kb, (page));
 115}
 116
 117static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
 118{
 119        return queue_var_show(queue_max_segments(q), (page));
 120}
 121
 122static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
 123{
 124        return queue_var_show(q->limits.max_integrity_segments, (page));
 125}
 126
 127static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 128{
 129        if (blk_queue_cluster(q))
 130                return queue_var_show(queue_max_segment_size(q), (page));
 131
 132        return queue_var_show(PAGE_CACHE_SIZE, (page));
 133}
 134
 135static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 136{
 137        return queue_var_show(queue_logical_block_size(q), page);
 138}
 139
 140static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 141{
 142        return queue_var_show(queue_physical_block_size(q), page);
 143}
 144
 145static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 146{
 147        return queue_var_show(queue_io_min(q), page);
 148}
 149
 150static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 151{
 152        return queue_var_show(queue_io_opt(q), page);
 153}
 154
 155static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 156{
 157        return queue_var_show(q->limits.discard_granularity, page);
 158}
 159
 160static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 161{
 162        return sprintf(page, "%llu\n",
 163                       (unsigned long long)q->limits.max_discard_sectors << 9);
 164}
 165
 166static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 167{
 168        return queue_var_show(queue_discard_zeroes_data(q), page);
 169}
 170
 171static ssize_t
 172queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 173{
 174        unsigned long max_sectors_kb,
 175                max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 176                        page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
 177        ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 178
 179        if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 180                return -EINVAL;
 181
 182        spin_lock_irq(q->queue_lock);
 183        q->limits.max_sectors = max_sectors_kb << 1;
 184        spin_unlock_irq(q->queue_lock);
 185
 186        return ret;
 187}
 188
 189static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 190{
 191        int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 192
 193        return queue_var_show(max_hw_sectors_kb, (page));
 194}
 195
 196#define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 197static ssize_t                                                          \
 198queue_show_##name(struct request_queue *q, char *page)                  \
 199{                                                                       \
 200        int bit;                                                        \
 201        bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 202        return queue_var_show(neg ? !bit : bit, page);                  \
 203}                                                                       \
 204static ssize_t                                                          \
 205queue_store_##name(struct request_queue *q, const char *page, size_t count) \
 206{                                                                       \
 207        unsigned long val;                                              \
 208        ssize_t ret;                                                    \
 209        ret = queue_var_store(&val, page, count);                       \
 210        if (neg)                                                        \
 211                val = !val;                                             \
 212                                                                        \
 213        spin_lock_irq(q->queue_lock);                                   \
 214        if (val)                                                        \
 215                queue_flag_set(QUEUE_FLAG_##flag, q);                   \
 216        else                                                            \
 217                queue_flag_clear(QUEUE_FLAG_##flag, q);                 \
 218        spin_unlock_irq(q->queue_lock);                                 \
 219        return ret;                                                     \
 220}
 221
 222QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 223QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 224QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 225#undef QUEUE_SYSFS_BIT_FNS
 226
 227static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 228{
 229        return queue_var_show((blk_queue_nomerges(q) << 1) |
 230                               blk_queue_noxmerges(q), page);
 231}
 232
 233static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 234                                    size_t count)
 235{
 236        unsigned long nm;
 237        ssize_t ret = queue_var_store(&nm, page, count);
 238
 239        spin_lock_irq(q->queue_lock);
 240        queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 241        queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 242        if (nm == 2)
 243                queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 244        else if (nm)
 245                queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 246        spin_unlock_irq(q->queue_lock);
 247
 248        return ret;
 249}
 250
 251static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 252{
 253        bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 254        bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 255
 256        return queue_var_show(set << force, page);
 257}
 258
 259static ssize_t
 260queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 261{
 262        ssize_t ret = -EINVAL;
 263#if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
 264        unsigned long val;
 265
 266        ret = queue_var_store(&val, page, count);
 267        spin_lock_irq(q->queue_lock);
 268        if (val == 2) {
 269                queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 270                queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 271        } else if (val == 1) {
 272                queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 273                queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 274        } else if (val == 0) {
 275                queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 276                queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 277        }
 278        spin_unlock_irq(q->queue_lock);
 279#endif
 280        return ret;
 281}
 282
 283static struct queue_sysfs_entry queue_requests_entry = {
 284        .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 285        .show = queue_requests_show,
 286        .store = queue_requests_store,
 287};
 288
 289static struct queue_sysfs_entry queue_ra_entry = {
 290        .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 291        .show = queue_ra_show,
 292        .store = queue_ra_store,
 293};
 294
 295static struct queue_sysfs_entry queue_max_sectors_entry = {
 296        .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 297        .show = queue_max_sectors_show,
 298        .store = queue_max_sectors_store,
 299};
 300
 301static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 302        .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 303        .show = queue_max_hw_sectors_show,
 304};
 305
 306static struct queue_sysfs_entry queue_max_segments_entry = {
 307        .attr = {.name = "max_segments", .mode = S_IRUGO },
 308        .show = queue_max_segments_show,
 309};
 310
 311static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
 312        .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
 313        .show = queue_max_integrity_segments_show,
 314};
 315
 316static struct queue_sysfs_entry queue_max_segment_size_entry = {
 317        .attr = {.name = "max_segment_size", .mode = S_IRUGO },
 318        .show = queue_max_segment_size_show,
 319};
 320
 321static struct queue_sysfs_entry queue_iosched_entry = {
 322        .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 323        .show = elv_iosched_show,
 324        .store = elv_iosched_store,
 325};
 326
 327static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 328        .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 329        .show = queue_logical_block_size_show,
 330};
 331
 332static struct queue_sysfs_entry queue_logical_block_size_entry = {
 333        .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 334        .show = queue_logical_block_size_show,
 335};
 336
 337static struct queue_sysfs_entry queue_physical_block_size_entry = {
 338        .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 339        .show = queue_physical_block_size_show,
 340};
 341
 342static struct queue_sysfs_entry queue_io_min_entry = {
 343        .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 344        .show = queue_io_min_show,
 345};
 346
 347static struct queue_sysfs_entry queue_io_opt_entry = {
 348        .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 349        .show = queue_io_opt_show,
 350};
 351
 352static struct queue_sysfs_entry queue_discard_granularity_entry = {
 353        .attr = {.name = "discard_granularity", .mode = S_IRUGO },
 354        .show = queue_discard_granularity_show,
 355};
 356
 357static struct queue_sysfs_entry queue_discard_max_entry = {
 358        .attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
 359        .show = queue_discard_max_show,
 360};
 361
 362static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 363        .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
 364        .show = queue_discard_zeroes_data_show,
 365};
 366
 367static struct queue_sysfs_entry queue_nonrot_entry = {
 368        .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 369        .show = queue_show_nonrot,
 370        .store = queue_store_nonrot,
 371};
 372
 373static struct queue_sysfs_entry queue_nomerges_entry = {
 374        .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 375        .show = queue_nomerges_show,
 376        .store = queue_nomerges_store,
 377};
 378
 379static struct queue_sysfs_entry queue_rq_affinity_entry = {
 380        .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 381        .show = queue_rq_affinity_show,
 382        .store = queue_rq_affinity_store,
 383};
 384
 385static struct queue_sysfs_entry queue_iostats_entry = {
 386        .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 387        .show = queue_show_iostats,
 388        .store = queue_store_iostats,
 389};
 390
 391static struct queue_sysfs_entry queue_random_entry = {
 392        .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
 393        .show = queue_show_random,
 394        .store = queue_store_random,
 395};
 396
 397static struct attribute *default_attrs[] = {
 398        &queue_requests_entry.attr,
 399        &queue_ra_entry.attr,
 400        &queue_max_hw_sectors_entry.attr,
 401        &queue_max_sectors_entry.attr,
 402        &queue_max_segments_entry.attr,
 403        &queue_max_integrity_segments_entry.attr,
 404        &queue_max_segment_size_entry.attr,
 405        &queue_iosched_entry.attr,
 406        &queue_hw_sector_size_entry.attr,
 407        &queue_logical_block_size_entry.attr,
 408        &queue_physical_block_size_entry.attr,
 409        &queue_io_min_entry.attr,
 410        &queue_io_opt_entry.attr,
 411        &queue_discard_granularity_entry.attr,
 412        &queue_discard_max_entry.attr,
 413        &queue_discard_zeroes_data_entry.attr,
 414        &queue_nonrot_entry.attr,
 415        &queue_nomerges_entry.attr,
 416        &queue_rq_affinity_entry.attr,
 417        &queue_iostats_entry.attr,
 418        &queue_random_entry.attr,
 419        NULL,
 420};
 421
 422#define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 423
 424static ssize_t
 425queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 426{
 427        struct queue_sysfs_entry *entry = to_queue(attr);
 428        struct request_queue *q =
 429                container_of(kobj, struct request_queue, kobj);
 430        ssize_t res;
 431
 432        if (!entry->show)
 433                return -EIO;
 434        mutex_lock(&q->sysfs_lock);
 435        if (blk_queue_dead(q)) {
 436                mutex_unlock(&q->sysfs_lock);
 437                return -ENOENT;
 438        }
 439        res = entry->show(q, page);
 440        mutex_unlock(&q->sysfs_lock);
 441        return res;
 442}
 443
 444static ssize_t
 445queue_attr_store(struct kobject *kobj, struct attribute *attr,
 446                    const char *page, size_t length)
 447{
 448        struct queue_sysfs_entry *entry = to_queue(attr);
 449        struct request_queue *q;
 450        ssize_t res;
 451
 452        if (!entry->store)
 453                return -EIO;
 454
 455        q = container_of(kobj, struct request_queue, kobj);
 456        mutex_lock(&q->sysfs_lock);
 457        if (blk_queue_dead(q)) {
 458                mutex_unlock(&q->sysfs_lock);
 459                return -ENOENT;
 460        }
 461        res = entry->store(q, page, length);
 462        mutex_unlock(&q->sysfs_lock);
 463        return res;
 464}
 465
 466/**
 467 * blk_release_queue: - release a &struct request_queue when it is no longer needed
 468 * @kobj:    the kobj belonging to the request queue to be released
 469 *
 470 * Description:
 471 *     blk_release_queue is the pair to blk_init_queue() or
 472 *     blk_queue_make_request().  It should be called when a request queue is
 473 *     being released; typically when a block device is being de-registered.
 474 *     Currently, its primary task it to free all the &struct request
 475 *     structures that were allocated to the queue and the queue itself.
 476 *
 477 * Caveat:
 478 *     Hopefully the low level driver will have finished any
 479 *     outstanding requests first...
 480 **/
 481static void blk_release_queue(struct kobject *kobj)
 482{
 483        struct request_queue *q =
 484                container_of(kobj, struct request_queue, kobj);
 485
 486        blk_sync_queue(q);
 487
 488        blkcg_exit_queue(q);
 489
 490        if (q->elevator) {
 491                spin_lock_irq(q->queue_lock);
 492                ioc_clear_queue(q);
 493                spin_unlock_irq(q->queue_lock);
 494                elevator_exit(q->elevator);
 495        }
 496
 497        blk_exit_rl(&q->root_rl);
 498
 499        if (q->queue_tags)
 500                __blk_queue_free_tags(q);
 501
 502        blk_trace_shutdown(q);
 503
 504        bdi_destroy(&q->backing_dev_info);
 505
 506        ida_simple_remove(&blk_queue_ida, q->id);
 507        kmem_cache_free(blk_requestq_cachep, q);
 508}
 509
 510static const struct sysfs_ops queue_sysfs_ops = {
 511        .show   = queue_attr_show,
 512        .store  = queue_attr_store,
 513};
 514
 515struct kobj_type blk_queue_ktype = {
 516        .sysfs_ops      = &queue_sysfs_ops,
 517        .default_attrs  = default_attrs,
 518        .release        = blk_release_queue,
 519};
 520
 521int blk_register_queue(struct gendisk *disk)
 522{
 523        int ret;
 524        struct device *dev = disk_to_dev(disk);
 525        struct request_queue *q = disk->queue;
 526
 527        if (WARN_ON(!q))
 528                return -ENXIO;
 529
 530        ret = blk_trace_init_sysfs(dev);
 531        if (ret)
 532                return ret;
 533
 534        ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 535        if (ret < 0) {
 536                blk_trace_remove_sysfs(dev);
 537                return ret;
 538        }
 539
 540        kobject_uevent(&q->kobj, KOBJ_ADD);
 541
 542        if (!q->request_fn)
 543                return 0;
 544
 545        ret = elv_register_queue(q);
 546        if (ret) {
 547                kobject_uevent(&q->kobj, KOBJ_REMOVE);
 548                kobject_del(&q->kobj);
 549                blk_trace_remove_sysfs(dev);
 550                kobject_put(&dev->kobj);
 551                return ret;
 552        }
 553
 554        return 0;
 555}
 556
 557void blk_unregister_queue(struct gendisk *disk)
 558{
 559        struct request_queue *q = disk->queue;
 560
 561        if (WARN_ON(!q))
 562                return;
 563
 564        if (q->request_fn)
 565                elv_unregister_queue(q);
 566
 567        kobject_uevent(&q->kobj, KOBJ_REMOVE);
 568        kobject_del(&q->kobj);
 569        blk_trace_remove_sysfs(disk_to_dev(disk));
 570        kobject_put(&disk_to_dev(disk)->kobj);
 571}
 572
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.