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 = queue_max_sectors(q) >> 1;
  99
 100         return queue_var_show(max_sectors_kb, (page));
 101 }
 102
 103 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 104 {
 105         return queue_var_show(queue_logical_block_size(q), page);
 106 }
 107
 108 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 109 {
 110         return queue_var_show(queue_physical_block_size(q), page);
 111 }
 112
 113 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 114 {
 115         return queue_var_show(queue_io_min(q), page);
 116 }
 117
 118 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 119 {
 120         return queue_var_show(queue_io_opt(q), page);
 121 }
 122
 123 static ssize_t
 124 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 125 {
 126         unsigned long max_sectors_kb,
 127                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 128                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
 129         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 130
 131         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 132                 return -EINVAL;
 133
 134         spin_lock_irq(q->queue_lock);
 135         blk_queue_max_sectors(q, max_sectors_kb << 1);
 136         spin_unlock_irq(q->queue_lock);
 137
 138         return ret;
 139 }
 140
 141 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 142 {
 143         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 144
 145         return queue_var_show(max_hw_sectors_kb, (page));
 146 }
 147
 148 static ssize_t queue_nonrot_show(struct request_queue *q, char *page)
 149 {
 150         return queue_var_show(!blk_queue_nonrot(q), page);
 151 }
 152
 153 static ssize_t queue_nonrot_store(struct request_queue *q, const char *page,
 154                                   size_t count)
 155 {
 156         unsigned long nm;
 157         ssize_t ret = queue_var_store(&nm, page, count);
 158
 159         spin_lock_irq(q->queue_lock);
 160         if (nm)
 161                 queue_flag_clear(QUEUE_FLAG_NONROT, q);
 162         else
 163                 queue_flag_set(QUEUE_FLAG_NONROT, q);
 164         spin_unlock_irq(q->queue_lock);
 165
 166         return ret;
 167 }
 168
 169 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 170 {
 171         return queue_var_show(blk_queue_nomerges(q), page);
 172 }
 173
 174 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 175                                     size_t count)
 176 {
 177         unsigned long nm;
 178         ssize_t ret = queue_var_store(&nm, page, count);
 179
 180         spin_lock_irq(q->queue_lock);
 181         if (nm)
 182                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 183         else
 184                 queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 185         spin_unlock_irq(q->queue_lock);
 186
 187         return ret;
 188 }
 189
 190 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 191 {
 192         unsigned int set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 193
 194         return queue_var_show(set != 0, page);
 195 }
 196
 197 static ssize_t
 198 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 199 {
 200         ssize_t ret = -EINVAL;
 201 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
 202         unsigned long val;
 203
 204         ret = queue_var_store(&val, page, count);
 205         spin_lock_irq(q->queue_lock);
 206         if (val)
 207                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 208         else
 209                 queue_flag_clear(QUEUE_FLAG_SAME_COMP,  q);
 210         spin_unlock_irq(q->queue_lock);
 211 #endif
 212         return ret;
 213 }
 214
 215 static ssize_t queue_iostats_show(struct request_queue *q, char *page)
 216 {
 217         return queue_var_show(blk_queue_io_stat(q), page);
 218 }
 219
 220 static ssize_t queue_iostats_store(struct request_queue *q, const char *page,
 221                                    size_t count)
 222 {
 223         unsigned long stats;
 224         ssize_t ret = queue_var_store(&stats, page, count);
 225
 226         spin_lock_irq(q->queue_lock);
 227         if (stats)
 228                 queue_flag_set(QUEUE_FLAG_IO_STAT, q);
 229         else
 230                 queue_flag_clear(QUEUE_FLAG_IO_STAT, q);
 231         spin_unlock_irq(q->queue_lock);
 232
 233         return ret;
 234 }
 235
 236 static struct queue_sysfs_entry queue_requests_entry = {
 237         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 238         .show = queue_requests_show,
 239         .store = queue_requests_store,
 240 };
 241
 242 static struct queue_sysfs_entry queue_ra_entry = {
 243         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 244         .show = queue_ra_show,
 245         .store = queue_ra_store,
 246 };
 247
 248 static struct queue_sysfs_entry queue_max_sectors_entry = {
 249         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 250         .show = queue_max_sectors_show,
 251         .store = queue_max_sectors_store,
 252 };
 253
 254 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 255         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 256         .show = queue_max_hw_sectors_show,
 257 };
 258
 259 static struct queue_sysfs_entry queue_iosched_entry = {
 260         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 261         .show = elv_iosched_show,
 262         .store = elv_iosched_store,
 263 };
 264
 265 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 266         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 267         .show = queue_logical_block_size_show,
 268 };
 269
 270 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 271         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 272         .show = queue_logical_block_size_show,
 273 };
 274
 275 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 276         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 277         .show = queue_physical_block_size_show,
 278 };
 279
 280 static struct queue_sysfs_entry queue_io_min_entry = {
 281         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 282         .show = queue_io_min_show,
 283 };
 284
 285 static struct queue_sysfs_entry queue_io_opt_entry = {
 286         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 287         .show = queue_io_opt_show,
 288 };
 289
 290 static struct queue_sysfs_entry queue_nonrot_entry = {
 291         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 292         .show = queue_nonrot_show,
 293         .store = queue_nonrot_store,
 294 };
 295
 296 static struct queue_sysfs_entry queue_nomerges_entry = {
 297         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 298         .show = queue_nomerges_show,
 299         .store = queue_nomerges_store,
 300 };
 301
 302 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 303         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 304         .show = queue_rq_affinity_show,
 305         .store = queue_rq_affinity_store,
 306 };
 307
 308 static struct queue_sysfs_entry queue_iostats_entry = {
 309         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 310         .show = queue_iostats_show,
 311         .store = queue_iostats_store,
 312 };
 313
 314 static struct attribute *default_attrs[] = {
 315         &queue_requests_entry.attr,
 316         &queue_ra_entry.attr,
 317         &queue_max_hw_sectors_entry.attr,
 318         &queue_max_sectors_entry.attr,
 319         &queue_iosched_entry.attr,
 320         &queue_hw_sector_size_entry.attr,
 321         &queue_logical_block_size_entry.attr,
 322         &queue_physical_block_size_entry.attr,
 323         &queue_io_min_entry.attr,
 324         &queue_io_opt_entry.attr,
 325         &queue_nonrot_entry.attr,
 326         &queue_nomerges_entry.attr,
 327         &queue_rq_affinity_entry.attr,
 328         &queue_iostats_entry.attr,
 329         NULL,
 330 };
 331
 332 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 333
 334 static ssize_t
 335 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 336 {
 337         struct queue_sysfs_entry *entry = to_queue(attr);
 338         struct request_queue *q =
 339                 container_of(kobj, struct request_queue, kobj);
 340         ssize_t res;
 341
 342         if (!entry->show)
 343                 return -EIO;
 344         mutex_lock(&q->sysfs_lock);
 345         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 346                 mutex_unlock(&q->sysfs_lock);
 347                 return -ENOENT;
 348         }
 349         res = entry->show(q, page);
 350         mutex_unlock(&q->sysfs_lock);
 351         return res;
 352 }
 353
 354 static ssize_t
 355 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 356                     const char *page, size_t length)
 357 {
 358         struct queue_sysfs_entry *entry = to_queue(attr);
 359         struct request_queue *q;
 360         ssize_t res;
 361
 362         if (!entry->store)
 363                 return -EIO;
 364
 365         q = container_of(kobj, struct request_queue, kobj);
 366         mutex_lock(&q->sysfs_lock);
 367         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 368                 mutex_unlock(&q->sysfs_lock);
 369                 return -ENOENT;
 370         }
 371         res = entry->store(q, page, length);
 372         mutex_unlock(&q->sysfs_lock);
 373         return res;
 374 }
 375
 376 /**
 377  * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
 378  * @kobj:    the kobj belonging of the request queue to be released
 379  *
 380  * Description:
 381  *     blk_cleanup_queue is the pair to blk_init_queue() or
 382  *     blk_queue_make_request().  It should be called when a request queue is
 383  *     being released; typically when a block device is being de-registered.
 384  *     Currently, its primary task it to free all the &struct request
 385  *     structures that were allocated to the queue and the queue itself.
 386  *
 387  * Caveat:
 388  *     Hopefully the low level driver will have finished any
 389  *     outstanding requests first...
 390  **/
 391 static void blk_release_queue(struct kobject *kobj)
 392 {
 393         struct request_queue *q =
 394                 container_of(kobj, struct request_queue, kobj);
 395         struct request_list *rl = &q->rq;
 396
 397         blk_sync_queue(q);
 398
 399         if (rl->rq_pool)
 400                 mempool_destroy(rl->rq_pool);
 401
 402         if (q->queue_tags)
 403                 __blk_queue_free_tags(q);
 404
 405         blk_trace_shutdown(q);
 406
 407         bdi_destroy(&q->backing_dev_info);
 408         kmem_cache_free(blk_requestq_cachep, q);
 409 }
 410
 411 static struct sysfs_ops queue_sysfs_ops = {
 412         .show   = queue_attr_show,
 413         .store  = queue_attr_store,
 414 };
 415
 416 struct kobj_type blk_queue_ktype = {
 417         .sysfs_ops      = &queue_sysfs_ops,
 418         .default_attrs  = default_attrs,
 419         .release        = blk_release_queue,
 420 };
 421
 422 int blk_register_queue(struct gendisk *disk)
 423 {
 424         int ret;
 425         struct device *dev = disk_to_dev(disk);
 426
 427         struct request_queue *q = disk->queue;
 428
 429         if (WARN_ON(!q))
 430                 return -ENXIO;
 431
 432         ret = blk_trace_init_sysfs(dev);
 433         if (ret)
 434                 return ret;
 435
 436         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 437         if (ret < 0)
 438                 return ret;
 439
 440         kobject_uevent(&q->kobj, KOBJ_ADD);
 441
 442         if (!q->request_fn)
 443                 return 0;
 444
 445         ret = elv_register_queue(q);
 446         if (ret) {
 447                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 448                 kobject_del(&q->kobj);
 449                 return ret;
 450         }
 451
 452         return 0;
 453 }
 454
 455 void blk_unregister_queue(struct gendisk *disk)
 456 {
 457         struct request_queue *q = disk->queue;
 458
 459         if (WARN_ON(!q))
 460                 return;
 461
 462         if (q->request_fn) {
 463                 elv_unregister_queue(q);
 464
 465                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 466                 kobject_del(&q->kobj);
 467                 kobject_put(&disk_to_dev(disk)->kobj);
 468         }
 469 }