block/blk-sysfs.c

   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
  12 struct 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
  18 static ssize_t
  19 queue_var_show(unsigned int var, char *page)
  20 {
  21         return sprintf(page, "%d\n", var);
  22 }
  23
  24 static ssize_t
  25 queue_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
  33 static ssize_t queue_requests_show(struct request_queue *q, char *page)
  34 {
  35         return queue_var_show(q->nr_requests, (page));
  36 }
  37
  38 static ssize_t
  39 queue_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[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
  52                 blk_set_queue_congested(q, BLK_RW_SYNC);
  53         else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
  54                 blk_clear_queue_congested(q, BLK_RW_SYNC);
  55
  56         if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
  57                 blk_set_queue_congested(q, BLK_RW_ASYNC);
  58         else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
  59                 blk_clear_queue_congested(q, BLK_RW_ASYNC);
  60
  61         if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
  62                 blk_set_queue_full(q, BLK_RW_SYNC);
  63         } else if (rl->count[BLK_RW_SYNC]+1 <= q->nr_requests) {
  64                 blk_clear_queue_full(q, BLK_RW_SYNC);
  65                 wake_up(&rl->wait[BLK_RW_SYNC]);
  66         }
  67
  68         if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
  69                 blk_set_queue_full(q, BLK_RW_ASYNC);
  70         } else if (rl->count[BLK_RW_ASYNC]+1 <= q->nr_requests) {
  71                 blk_clear_queue_full(q, BLK_RW_ASYNC);
  72                 wake_up(&rl->wait[BLK_RW_ASYNC]);
  73         }
  74         spin_unlock_irq(q->queue_lock);
  75         return ret;
  76 }
  77
  78 static 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
  85 static ssize_t
  86 queue_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
  96 static 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
 103 static 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
 108 static ssize_t
 109 queue_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
 126 static 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
 133 static ssize_t queue_nonrot_show(struct request_queue *q, char *page)
 134 {
 135         return queue_var_show(!blk_queue_nonrot(q), page);
 136 }
 137
 138 static 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
 154 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 155 {
 156         return queue_var_show(blk_queue_nomerges(q), page);
 157 }
 158
 159 static 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
 175 static 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
 182 static ssize_t
 183 queue_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
 200 static 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
 205 static 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         elv_quisce_start(q);
 213
 214         if (stats)
 215                 queue_flag_set(QUEUE_FLAG_IO_STAT, q);
 216         else
 217                 queue_flag_clear(QUEUE_FLAG_IO_STAT, q);
 218
 219         elv_quisce_end(q);
 220         spin_unlock_irq(q->queue_lock);
 221
 222         return ret;
 223 }
 224
 225 static struct queue_sysfs_entry queue_requests_entry = {
 226         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 227         .show = queue_requests_show,
 228         .store = queue_requests_store,
 229 };
 230
 231 static struct queue_sysfs_entry queue_ra_entry = {
 232         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 233         .show = queue_ra_show,
 234         .store = queue_ra_store,
 235 };
 236
 237 static struct queue_sysfs_entry queue_max_sectors_entry = {
 238         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 239         .show = queue_max_sectors_show,
 240         .store = queue_max_sectors_store,
 241 };
 242
 243 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 244         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 245         .show = queue_max_hw_sectors_show,
 246 };
 247
 248 static struct queue_sysfs_entry queue_iosched_entry = {
 249         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 250         .show = elv_iosched_show,
 251         .store = elv_iosched_store,
 252 };
 253
 254 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 255         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 256         .show = queue_hw_sector_size_show,
 257 };
 258
 259 static struct queue_sysfs_entry queue_nonrot_entry = {
 260         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 261         .show = queue_nonrot_show,
 262         .store = queue_nonrot_store,
 263 };
 264
 265 static struct queue_sysfs_entry queue_nomerges_entry = {
 266         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 267         .show = queue_nomerges_show,
 268         .store = queue_nomerges_store,
 269 };
 270
 271 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 272         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 273         .show = queue_rq_affinity_show,
 274         .store = queue_rq_affinity_store,
 275 };
 276
 277 static struct queue_sysfs_entry queue_iostats_entry = {
 278         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 279         .show = queue_iostats_show,
 280         .store = queue_iostats_store,
 281 };
 282
 283 static struct attribute *default_attrs[] = {
 284         &queue_requests_entry.attr,
 285         &queue_ra_entry.attr,
 286         &queue_max_hw_sectors_entry.attr,
 287         &queue_max_sectors_entry.attr,
 288         &queue_iosched_entry.attr,
 289         &queue_hw_sector_size_entry.attr,
 290         &queue_nonrot_entry.attr,
 291         &queue_nomerges_entry.attr,
 292         &queue_rq_affinity_entry.attr,
 293         &queue_iostats_entry.attr,
 294         NULL,
 295 };
 296
 297 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 298
 299 static ssize_t
 300 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 301 {
 302         struct queue_sysfs_entry *entry = to_queue(attr);
 303         struct request_queue *q =
 304                 container_of(kobj, struct request_queue, kobj);
 305         ssize_t res;
 306
 307         if (!entry->show)
 308                 return -EIO;
 309         mutex_lock(&q->sysfs_lock);
 310         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 311                 mutex_unlock(&q->sysfs_lock);
 312                 return -ENOENT;
 313         }
 314         res = entry->show(q, page);
 315         mutex_unlock(&q->sysfs_lock);
 316         return res;
 317 }
 318
 319 static ssize_t
 320 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 321                     const char *page, size_t length)
 322 {
 323         struct queue_sysfs_entry *entry = to_queue(attr);
 324         struct request_queue *q;
 325         ssize_t res;
 326
 327         if (!entry->store)
 328                 return -EIO;
 329
 330         q = container_of(kobj, struct request_queue, kobj);
 331         mutex_lock(&q->sysfs_lock);
 332         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 333                 mutex_unlock(&q->sysfs_lock);
 334                 return -ENOENT;
 335         }
 336         res = entry->store(q, page, length);
 337         mutex_unlock(&q->sysfs_lock);
 338         return res;
 339 }
 340
 341 /**
 342  * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
 343  * @kobj:    the kobj belonging of the request queue to be released
 344  *
 345  * Description:
 346  *     blk_cleanup_queue is the pair to blk_init_queue() or
 347  *     blk_queue_make_request().  It should be called when a request queue is
 348  *     being released; typically when a block device is being de-registered.
 349  *     Currently, its primary task it to free all the &struct request
 350  *     structures that were allocated to the queue and the queue itself.
 351  *
 352  * Caveat:
 353  *     Hopefully the low level driver will have finished any
 354  *     outstanding requests first...
 355  **/
 356 static void blk_release_queue(struct kobject *kobj)
 357 {
 358         struct request_queue *q =
 359                 container_of(kobj, struct request_queue, kobj);
 360         struct request_list *rl = &q->rq;
 361
 362         blk_sync_queue(q);
 363
 364         if (rl->rq_pool)
 365                 mempool_destroy(rl->rq_pool);
 366
 367         if (q->queue_tags)
 368                 __blk_queue_free_tags(q);
 369
 370         blk_trace_shutdown(q);
 371
 372         bdi_destroy(&q->backing_dev_info);
 373         kmem_cache_free(blk_requestq_cachep, q);
 374 }
 375
 376 static struct sysfs_ops queue_sysfs_ops = {
 377         .show   = queue_attr_show,
 378         .store  = queue_attr_store,
 379 };
 380
 381 struct kobj_type blk_queue_ktype = {
 382         .sysfs_ops      = &queue_sysfs_ops,
 383         .default_attrs  = default_attrs,
 384         .release        = blk_release_queue,
 385 };
 386
 387 int blk_register_queue(struct gendisk *disk)
 388 {
 389         int ret;
 390
 391         struct request_queue *q = disk->queue;
 392
 393         if (WARN_ON(!q))
 394                 return -ENXIO;
 395
 396         if (!q->request_fn)
 397                 return 0;
 398
 399         ret = kobject_add(&q->kobj, kobject_get(&disk_to_dev(disk)->kobj),
 400                           "%s", "queue");
 401         if (ret < 0)
 402                 return ret;
 403
 404         kobject_uevent(&q->kobj, KOBJ_ADD);
 405
 406         ret = elv_register_queue(q);
 407         if (ret) {
 408                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 409                 kobject_del(&q->kobj);
 410                 return ret;
 411         }
 412
 413         return 0;
 414 }
 415
 416 void blk_unregister_queue(struct gendisk *disk)
 417 {
 418         struct request_queue *q = disk->queue;
 419
 420         if (WARN_ON(!q))
 421                 return;
 422
 423         if (q->request_fn) {
 424                 elv_unregister_queue(q);
 425
 426                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 427                 kobject_del(&q->kobj);
 428                 kobject_put(&disk_to_dev(disk)->kobj);
 429         }
 430 }