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 long var, char *page)
  20 {
  21         return sprintf(page, "%lu\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;
  44
  45         if (!q->request_fn)
  46                 return -EINVAL;
  47
  48         ret = queue_var_store(&nr, page, count);
  49         if (nr < BLKDEV_MIN_RQ)
  50                 nr = BLKDEV_MIN_RQ;
  51
  52         spin_lock_irq(q->queue_lock);
  53         q->nr_requests = nr;
  54         blk_queue_congestion_threshold(q);
  55
  56         if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
  57                 blk_set_queue_congested(q, BLK_RW_SYNC);
  58         else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
  59                 blk_clear_queue_congested(q, BLK_RW_SYNC);
  60
  61         if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
  62                 blk_set_queue_congested(q, BLK_RW_ASYNC);
  63         else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
  64                 blk_clear_queue_congested(q, BLK_RW_ASYNC);
  65
  66         if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
  67                 blk_set_queue_full(q, BLK_RW_SYNC);
  68         } else if (rl->count[BLK_RW_SYNC]+1 <= q->nr_requests) {
  69                 blk_clear_queue_full(q, BLK_RW_SYNC);
  70                 wake_up(&rl->wait[BLK_RW_SYNC]);
  71         }
  72
  73         if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
  74                 blk_set_queue_full(q, BLK_RW_ASYNC);
  75         } else if (rl->count[BLK_RW_ASYNC]+1 <= q->nr_requests) {
  76                 blk_clear_queue_full(q, BLK_RW_ASYNC);
  77                 wake_up(&rl->wait[BLK_RW_ASYNC]);
  78         }
  79         spin_unlock_irq(q->queue_lock);
  80         return ret;
  81 }
  82
  83 static ssize_t queue_ra_show(struct request_queue *q, char *page)
  84 {
  85         unsigned long ra_kb = q->backing_dev_info.ra_pages <<
  86                                         (PAGE_CACHE_SHIFT - 10);
  87
  88         return queue_var_show(ra_kb, (page));
  89 }
  90
  91 static ssize_t
  92 queue_ra_store(struct request_queue *q, const char *page, size_t count)
  93 {
  94         unsigned long ra_kb;
  95         ssize_t ret = queue_var_store(&ra_kb, page, count);
  96
  97         q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
  98
  99         return ret;
 100 }
 101
 102 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
 103 {
 104         int max_sectors_kb = queue_max_sectors(q) >> 1;
 105
 106         return queue_var_show(max_sectors_kb, (page));
 107 }
 108
 109 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 110 {
 111         return queue_var_show(queue_logical_block_size(q), page);
 112 }
 113
 114 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 115 {
 116         return queue_var_show(queue_physical_block_size(q), page);
 117 }
 118
 119 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 120 {
 121         return queue_var_show(queue_io_min(q), page);
 122 }
 123
 124 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 125 {
 126         return queue_var_show(queue_io_opt(q), page);
 127 }
 128
 129 static ssize_t
 130 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 131 {
 132         unsigned long max_sectors_kb,
 133                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 134                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
 135         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 136
 137         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 138                 return -EINVAL;
 139
 140         spin_lock_irq(q->queue_lock);
 141         q->limits.max_sectors = max_sectors_kb << 1;
 142         spin_unlock_irq(q->queue_lock);
 143
 144         return ret;
 145 }
 146
 147 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 148 {
 149         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 150
 151         return queue_var_show(max_hw_sectors_kb, (page));
 152 }
 153
 154 static ssize_t queue_nonrot_show(struct request_queue *q, char *page)
 155 {
 156         return queue_var_show(!blk_queue_nonrot(q), page);
 157 }
 158
 159 static ssize_t queue_nonrot_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_clear(QUEUE_FLAG_NONROT, q);
 168         else
 169                 queue_flag_set(QUEUE_FLAG_NONROT, q);
 170         spin_unlock_irq(q->queue_lock);
 171
 172         return ret;
 173 }
 174
 175 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 176 {
 177         return queue_var_show(blk_queue_nomerges(q), page);
 178 }
 179
 180 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 181                                     size_t count)
 182 {
 183         unsigned long nm;
 184         ssize_t ret = queue_var_store(&nm, page, count);
 185
 186         spin_lock_irq(q->queue_lock);
 187         if (nm)
 188                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 189         else
 190                 queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 191         spin_unlock_irq(q->queue_lock);
 192
 193         return ret;
 194 }
 195
 196 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 197 {
 198         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 199
 200         return queue_var_show(set, page);
 201 }
 202
 203 static ssize_t
 204 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 205 {
 206         ssize_t ret = -EINVAL;
 207 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
 208         unsigned long val;
 209
 210         ret = queue_var_store(&val, page, count);
 211         spin_lock_irq(q->queue_lock);
 212         if (val)
 213                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 214         else
 215                 queue_flag_clear(QUEUE_FLAG_SAME_COMP,  q);
 216         spin_unlock_irq(q->queue_lock);
 217 #endif
 218         return ret;
 219 }
 220
 221 static ssize_t queue_iostats_show(struct request_queue *q, char *page)
 222 {
 223         return queue_var_show(blk_queue_io_stat(q), page);
 224 }
 225
 226 static ssize_t queue_iostats_store(struct request_queue *q, const char *page,
 227                                    size_t count)
 228 {
 229         unsigned long stats;
 230         ssize_t ret = queue_var_store(&stats, page, count);
 231
 232         spin_lock_irq(q->queue_lock);
 233         if (stats)
 234                 queue_flag_set(QUEUE_FLAG_IO_STAT, q);
 235         else
 236                 queue_flag_clear(QUEUE_FLAG_IO_STAT, q);
 237         spin_unlock_irq(q->queue_lock);
 238
 239         return ret;
 240 }
 241
 242 static struct queue_sysfs_entry queue_requests_entry = {
 243         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 244         .show = queue_requests_show,
 245         .store = queue_requests_store,
 246 };
 247
 248 static struct queue_sysfs_entry queue_ra_entry = {
 249         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 250         .show = queue_ra_show,
 251         .store = queue_ra_store,
 252 };
 253
 254 static struct queue_sysfs_entry queue_max_sectors_entry = {
 255         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 256         .show = queue_max_sectors_show,
 257         .store = queue_max_sectors_store,
 258 };
 259
 260 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 261         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 262         .show = queue_max_hw_sectors_show,
 263 };
 264
 265 static struct queue_sysfs_entry queue_iosched_entry = {
 266         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 267         .show = elv_iosched_show,
 268         .store = elv_iosched_store,
 269 };
 270
 271 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 272         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 273         .show = queue_logical_block_size_show,
 274 };
 275
 276 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 277         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 278         .show = queue_logical_block_size_show,
 279 };
 280
 281 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 282         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 283         .show = queue_physical_block_size_show,
 284 };
 285
 286 static struct queue_sysfs_entry queue_io_min_entry = {
 287         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 288         .show = queue_io_min_show,
 289 };
 290
 291 static struct queue_sysfs_entry queue_io_opt_entry = {
 292         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 293         .show = queue_io_opt_show,
 294 };
 295
 296 static struct queue_sysfs_entry queue_nonrot_entry = {
 297         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 298         .show = queue_nonrot_show,
 299         .store = queue_nonrot_store,
 300 };
 301
 302 static struct queue_sysfs_entry queue_nomerges_entry = {
 303         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 304         .show = queue_nomerges_show,
 305         .store = queue_nomerges_store,
 306 };
 307
 308 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 309         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 310         .show = queue_rq_affinity_show,
 311         .store = queue_rq_affinity_store,
 312 };
 313
 314 static struct queue_sysfs_entry queue_iostats_entry = {
 315         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 316         .show = queue_iostats_show,
 317         .store = queue_iostats_store,
 318 };
 319
 320 static struct attribute *default_attrs[] = {
 321         &queue_requests_entry.attr,
 322         &queue_ra_entry.attr,
 323         &queue_max_hw_sectors_entry.attr,
 324         &queue_max_sectors_entry.attr,
 325         &queue_iosched_entry.attr,
 326         &queue_hw_sector_size_entry.attr,
 327         &queue_logical_block_size_entry.attr,
 328         &queue_physical_block_size_entry.attr,
 329         &queue_io_min_entry.attr,
 330         &queue_io_opt_entry.attr,
 331         &queue_nonrot_entry.attr,
 332         &queue_nomerges_entry.attr,
 333         &queue_rq_affinity_entry.attr,
 334         &queue_iostats_entry.attr,
 335         NULL,
 336 };
 337
 338 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 339
 340 static ssize_t
 341 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 342 {
 343         struct queue_sysfs_entry *entry = to_queue(attr);
 344         struct request_queue *q =
 345                 container_of(kobj, struct request_queue, kobj);
 346         ssize_t res;
 347
 348         if (!entry->show)
 349                 return -EIO;
 350         mutex_lock(&q->sysfs_lock);
 351         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 352                 mutex_unlock(&q->sysfs_lock);
 353                 return -ENOENT;
 354         }
 355         res = entry->show(q, page);
 356         mutex_unlock(&q->sysfs_lock);
 357         return res;
 358 }
 359
 360 static ssize_t
 361 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 362                     const char *page, size_t length)
 363 {
 364         struct queue_sysfs_entry *entry = to_queue(attr);
 365         struct request_queue *q;
 366         ssize_t res;
 367
 368         if (!entry->store)
 369                 return -EIO;
 370
 371         q = container_of(kobj, struct request_queue, kobj);
 372         mutex_lock(&q->sysfs_lock);
 373         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 374                 mutex_unlock(&q->sysfs_lock);
 375                 return -ENOENT;
 376         }
 377         res = entry->store(q, page, length);
 378         mutex_unlock(&q->sysfs_lock);
 379         return res;
 380 }
 381
 382 /**
 383  * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
 384  * @kobj:    the kobj belonging of the request queue to be released
 385  *
 386  * Description:
 387  *     blk_cleanup_queue is the pair to blk_init_queue() or
 388  *     blk_queue_make_request().  It should be called when a request queue is
 389  *     being released; typically when a block device is being de-registered.
 390  *     Currently, its primary task it to free all the &struct request
 391  *     structures that were allocated to the queue and the queue itself.
 392  *
 393  * Caveat:
 394  *     Hopefully the low level driver will have finished any
 395  *     outstanding requests first...
 396  **/
 397 static void blk_release_queue(struct kobject *kobj)
 398 {
 399         struct request_queue *q =
 400                 container_of(kobj, struct request_queue, kobj);
 401         struct request_list *rl = &q->rq;
 402
 403         blk_sync_queue(q);
 404
 405         if (rl->rq_pool)
 406                 mempool_destroy(rl->rq_pool);
 407
 408         if (q->queue_tags)
 409                 __blk_queue_free_tags(q);
 410
 411         blk_trace_shutdown(q);
 412
 413         bdi_destroy(&q->backing_dev_info);
 414         kmem_cache_free(blk_requestq_cachep, q);
 415 }
 416
 417 static struct sysfs_ops queue_sysfs_ops = {
 418         .show   = queue_attr_show,
 419         .store  = queue_attr_store,
 420 };
 421
 422 struct kobj_type blk_queue_ktype = {
 423         .sysfs_ops      = &queue_sysfs_ops,
 424         .default_attrs  = default_attrs,
 425         .release        = blk_release_queue,
 426 };
 427
 428 int blk_register_queue(struct gendisk *disk)
 429 {
 430         int ret;
 431         struct device *dev = disk_to_dev(disk);
 432
 433         struct request_queue *q = disk->queue;
 434
 435         if (WARN_ON(!q))
 436                 return -ENXIO;
 437
 438         ret = blk_trace_init_sysfs(dev);
 439         if (ret)
 440                 return ret;
 441
 442         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 443         if (ret < 0) {
 444                 blk_trace_remove_sysfs(dev);
 445                 return ret;
 446         }
 447
 448         kobject_uevent(&q->kobj, KOBJ_ADD);
 449
 450         if (!q->request_fn)
 451                 return 0;
 452
 453         ret = elv_register_queue(q);
 454         if (ret) {
 455                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 456                 kobject_del(&q->kobj);
 457                 blk_trace_remove_sysfs(disk_to_dev(disk));
 458                 return ret;
 459         }
 460
 461         return 0;
 462 }
 463
 464 void blk_unregister_queue(struct gendisk *disk)
 465 {
 466         struct request_queue *q = disk->queue;
 467
 468         if (WARN_ON(!q))
 469                 return;
 470
 471         if (q->request_fn)
 472                 elv_unregister_queue(q);
 473
 474         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 475         kobject_del(&q->kobj);
 476         blk_trace_remove_sysfs(disk_to_dev(disk));
 477         kobject_put(&disk_to_dev(disk)->kobj);
 478 }