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/module.h>
   6#include <linux/bio.h>
   7#include <linux/blkdev.h>
   8#include <linux/blktrace_api.h>
   9
  10#include "blk.h"
  11
  12struct queue_sysfs_entry {
  13        struct attribute attr;
  14        ssize_t (*show)(struct request_queue *, char *);
  15        ssize_t (*store)(struct request_queue *, const char *, size_t);
  16};
  17
  18static ssize_t
  19queue_var_show(unsigned int var, char *page)
  20{
  21        return sprintf(page, "%d\n", var);
  22}
  23
  24static ssize_t
  25queue_var_store(unsigned long *var, const char *page, size_t count)
  26{
  27        char *p = (char *) page;
  28
  29        *var = simple_strtoul(p, &p, 10);
  30        return count;
  31}
  32
  33static ssize_t queue_requests_show(struct request_queue *q, char *page)
  34{
  35        return queue_var_show(q->nr_requests, (page));
  36}
  37
  38static ssize_t
  39queue_requests_store(struct request_queue *q, const char *page, size_t count)
  40{
  41        struct request_list *rl = &q->rq;
  42        unsigned long nr;
  43        int ret = queue_var_store(&nr, page, count);
  44        if (nr < BLKDEV_MIN_RQ)
  45                nr = BLKDEV_MIN_RQ;
  46
  47        spin_lock_irq(q->queue_lock);
  48        q->nr_requests = nr;
  49        blk_queue_congestion_threshold(q);
  50
  51        if (rl->count[READ] >= queue_congestion_on_threshold(q))
  52                blk_set_queue_congested(q, READ);
  53        else if (rl->count[READ] < queue_congestion_off_threshold(q))
  54                blk_clear_queue_congested(q, READ);
  55
  56        if (rl->count[WRITE] >= queue_congestion_on_threshold(q))
  57                blk_set_queue_congested(q, WRITE);
  58        else if (rl->count[WRITE] < queue_congestion_off_threshold(q))
  59                blk_clear_queue_congested(q, WRITE);
  60
  61        if (rl->count[READ] >= q->nr_requests) {
  62                blk_set_queue_full(q, READ);
  63        } else if (rl->count[READ]+1 <= q->nr_requests) {
  64                blk_clear_queue_full(q, READ);
  65                wake_up(&rl->wait[READ]);
  66        }
  67
  68        if (rl->count[WRITE] >= q->nr_requests) {
  69                blk_set_queue_full(q, WRITE);
  70        } else if (rl->count[WRITE]+1 <= q->nr_requests) {
  71                blk_clear_queue_full(q, WRITE);
  72                wake_up(&rl->wait[WRITE]);
  73        }
  74        spin_unlock_irq(q->queue_lock);
  75        return ret;
  76}
  77
  78static ssize_t queue_ra_show(struct request_queue *q, char *page)
  79{
  80        int ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10);
  81
  82        return queue_var_show(ra_kb, (page));
  83}
  84
  85static ssize_t
  86queue_ra_store(struct request_queue *q, const char *page, size_t count)
  87{
  88        unsigned long ra_kb;
  89        ssize_t ret = queue_var_store(&ra_kb, page, count);
  90
  91        q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
  92
  93        return ret;
  94}
  95
  96static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
  97{
  98        int max_sectors_kb = q->max_sectors >> 1;
  99
 100        return queue_var_show(max_sectors_kb, (page));
 101}
 102
 103static ssize_t queue_hw_sector_size_show(struct request_queue *q, char *page)
 104{
 105        return queue_var_show(q->hardsect_size, page);
 106}
 107
 108static ssize_t
 109queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 110{
 111        unsigned long max_sectors_kb,
 112                        max_hw_sectors_kb = q->max_hw_sectors >> 1,
 113                        page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
 114        ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 115
 116        if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 117                return -EINVAL;
 118
 119        spin_lock_irq(q->queue_lock);
 120        q->max_sectors = max_sectors_kb << 1;
 121        spin_unlock_irq(q->queue_lock);
 122
 123        return ret;
 124}
 125
 126static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 127{
 128        int max_hw_sectors_kb = q->max_hw_sectors >> 1;
 129
 130        return queue_var_show(max_hw_sectors_kb, (page));
 131}
 132
 133static ssize_t queue_nonrot_show(struct request_queue *q, char *page)
 134{
 135        return queue_var_show(!blk_queue_nonrot(q), page);
 136}
 137
 138static ssize_t queue_nonrot_store(struct request_queue *q, const char *page,
 139                                  size_t count)
 140{
 141        unsigned long nm;
 142        ssize_t ret = queue_var_store(&nm, page, count);
 143
 144        spin_lock_irq(q->queue_lock);
 145        if (nm)
 146                queue_flag_clear(QUEUE_FLAG_NONROT, q);
 147        else
 148                queue_flag_set(QUEUE_FLAG_NONROT, q);
 149        spin_unlock_irq(q->queue_lock);
 150
 151        return ret;
 152}
 153
 154static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 155{
 156        return queue_var_show(blk_queue_nomerges(q), page);
 157}
 158
 159static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 160                                    size_t count)
 161{
 162        unsigned long nm;
 163        ssize_t ret = queue_var_store(&nm, page, count);
 164
 165        spin_lock_irq(q->queue_lock);
 166        if (nm)
 167                queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 168        else
 169                queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 170        spin_unlock_irq(q->queue_lock);
 171
 172        return ret;
 173}
 174
 175static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 176{
 177        unsigned int set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 178
 179        return queue_var_show(set != 0, page);
 180}
 181
 182static ssize_t
 183queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 184{
 185        ssize_t ret = -EINVAL;
 186#if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
 187        unsigned long val;
 188
 189        ret = queue_var_store(&val, page, count);
 190        spin_lock_irq(q->queue_lock);
 191        if (val)
 192                queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 193        else
 194                queue_flag_clear(QUEUE_FLAG_SAME_COMP,  q);
 195        spin_unlock_irq(q->queue_lock);
 196#endif
 197        return ret;
 198}
 199
 200static ssize_t queue_iostats_show(struct request_queue *q, char *page)
 201{
 202        return queue_var_show(blk_queue_io_stat(q), page);
 203}
 204
 205static ssize_t queue_iostats_store(struct request_queue *q, const char *page,
 206                                   size_t count)
 207{
 208        unsigned long stats;
 209        ssize_t ret = queue_var_store(&stats, page, count);
 210
 211        spin_lock_irq(q->queue_lock);
 212        if (stats)
 213                queue_flag_set(QUEUE_FLAG_IO_STAT, q);
 214        else
 215                queue_flag_clear(QUEUE_FLAG_IO_STAT, q);
 216        spin_unlock_irq(q->queue_lock);
 217
 218        return ret;
 219}
 220
 221static struct queue_sysfs_entry queue_requests_entry = {
 222        .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 223        .show = queue_requests_show,
 224        .store = queue_requests_store,
 225};
 226
 227static struct queue_sysfs_entry queue_ra_entry = {
 228        .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 229        .show = queue_ra_show,
 230        .store = queue_ra_store,
 231};
 232
 233static struct queue_sysfs_entry queue_max_sectors_entry = {
 234        .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 235        .show = queue_max_sectors_show,
 236        .store = queue_max_sectors_store,
 237};
 238
 239static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 240        .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 241        .show = queue_max_hw_sectors_show,
 242};
 243
 244static struct queue_sysfs_entry queue_iosched_entry = {
 245        .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 246        .show = elv_iosched_show,
 247        .store = elv_iosched_store,
 248};
 249
 250static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 251        .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 252        .show = queue_hw_sector_size_show,
 253};
 254
 255static struct queue_sysfs_entry queue_nonrot_entry = {
 256        .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 257        .show = queue_nonrot_show,
 258        .store = queue_nonrot_store,
 259};
 260
 261static struct queue_sysfs_entry queue_nomerges_entry = {
 262        .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 263        .show = queue_nomerges_show,
 264        .store = queue_nomerges_store,
 265};
 266
 267static struct queue_sysfs_entry queue_rq_affinity_entry = {
 268        .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 269        .show = queue_rq_affinity_show,
 270        .store = queue_rq_affinity_store,
 271};
 272
 273static struct queue_sysfs_entry queue_iostats_entry = {
 274        .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 275        .show = queue_iostats_show,
 276        .store = queue_iostats_store,
 277};
 278
 279static struct attribute *default_attrs[] = {
 280        &queue_requests_entry.attr,
 281        &queue_ra_entry.attr,
 282        &queue_max_hw_sectors_entry.attr,
 283        &queue_max_sectors_entry.attr,
 284        &queue_iosched_entry.attr,
 285        &queue_hw_sector_size_entry.attr,
 286        &queue_nonrot_entry.attr,
 287        &queue_nomerges_entry.attr,
 288        &queue_rq_affinity_entry.attr,
 289        &queue_iostats_entry.attr,
 290        NULL,
 291};
 292
 293#define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 294
 295static ssize_t
 296queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 297{
 298        struct queue_sysfs_entry *entry = to_queue(attr);
 299        struct request_queue *q =
 300                container_of(kobj, struct request_queue, kobj);
 301        ssize_t res;
 302
 303        if (!entry->show)
 304                return -EIO;
 305        mutex_lock(&q->sysfs_lock);
 306        if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 307                mutex_unlock(&q->sysfs_lock);
 308                return -ENOENT;
 309        }
 310        res = entry->show(q, page);
 311        mutex_unlock(&q->sysfs_lock);
 312        return res;
 313}
 314
 315static ssize_t
 316queue_attr_store(struct kobject *kobj, struct attribute *attr,
 317                    const char *page, size_t length)
 318{
 319        struct queue_sysfs_entry *entry = to_queue(attr);
 320        struct request_queue *q;
 321        ssize_t res;
 322
 323        if (!entry->store)
 324                return -EIO;
 325
 326        q = container_of(kobj, struct request_queue, kobj);
 327        mutex_lock(&q->sysfs_lock);
 328        if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 329                mutex_unlock(&q->sysfs_lock);
 330                return -ENOENT;
 331        }
 332        res = entry->store(q, page, length);
 333        mutex_unlock(&q->sysfs_lock);
 334        return res;
 335}
 336
 337/**
 338 * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
 339 * @kobj:    the kobj belonging of the request queue to be released
 340 *
 341 * Description:
 342 *     blk_cleanup_queue is the pair to blk_init_queue() or
 343 *     blk_queue_make_request().  It should be called when a request queue is
 344 *     being released; typically when a block device is being de-registered.
 345 *     Currently, its primary task it to free all the &struct request
 346 *     structures that were allocated to the queue and the queue itself.
 347 *
 348 * Caveat:
 349 *     Hopefully the low level driver will have finished any
 350 *     outstanding requests first...
 351 **/
 352static void blk_release_queue(struct kobject *kobj)
 353{
 354        struct request_queue *q =
 355                container_of(kobj, struct request_queue, kobj);
 356        struct request_list *rl = &q->rq;
 357
 358        blk_sync_queue(q);
 359
 360        if (rl->rq_pool)
 361                mempool_destroy(rl->rq_pool);
 362
 363        if (q->queue_tags)
 364                __blk_queue_free_tags(q);
 365
 366        blk_trace_shutdown(q);
 367
 368        bdi_destroy(&q->backing_dev_info);
 369        kmem_cache_free(blk_requestq_cachep, q);
 370}
 371
 372static struct sysfs_ops queue_sysfs_ops = {
 373        .show   = queue_attr_show,
 374        .store  = queue_attr_store,
 375};
 376
 377struct kobj_type blk_queue_ktype = {
 378        .sysfs_ops      = &queue_sysfs_ops,
 379        .default_attrs  = default_attrs,
 380        .release        = blk_release_queue,
 381};
 382
 383int blk_register_queue(struct gendisk *disk)
 384{
 385        int ret;
 386
 387        struct request_queue *q = disk->queue;
 388
 389        if (WARN_ON(!q))
 390                return -ENXIO;
 391
 392        if (!q->request_fn)
 393                return 0;
 394
 395        ret = kobject_add(&q->kobj, kobject_get(&disk_to_dev(disk)->kobj),
 396                          "%s", "queue");
 397        if (ret < 0)
 398                return ret;
 399
 400        kobject_uevent(&q->kobj, KOBJ_ADD);
 401
 402        ret = elv_register_queue(q);
 403        if (ret) {
 404                kobject_uevent(&q->kobj, KOBJ_REMOVE);
 405                kobject_del(&q->kobj);
 406                return ret;
 407        }
 408
 409        return 0;
 410}
 411
 412void blk_unregister_queue(struct gendisk *disk)
 413{
 414        struct request_queue *q = disk->queue;
 415
 416        if (WARN_ON(!q))
 417                return;
 418
 419        if (q->request_fn) {
 420                elv_unregister_queue(q);
 421
 422                kobject_uevent(&q->kobj, KOBJ_REMOVE);
 423                kobject_del(&q->kobj);
 424                kobject_put(&disk_to_dev(disk)->kobj);
 425        }
 426}
 427