block/blk-sysfs.c

   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
  13 struct queue_sysfs_entry {
  14         struct attribute attr;
  15         ssize_t (*show)(struct request_queue *, char *);
  16         ssize_t (*store)(struct request_queue *, const char *, size_t);
  17 };
  18
  19 static ssize_t
  20 queue_var_show(unsigned long var, char *page)
  21 {
  22         return sprintf(page, "%lu\n", var);
  23 }
  24
  25 static ssize_t
  26 queue_var_store(unsigned long *var, const char *page, size_t count)
  27 {
  28         char *p = (char *) page;
  29
  30         *var = simple_strtoul(p, &p, 10);
  31         return count;
  32 }
  33
  34 static ssize_t queue_requests_show(struct request_queue *q, char *page)
  35 {
  36         return queue_var_show(q->nr_requests, (page));
  37 }
  38
  39 static ssize_t
  40 queue_requests_store(struct request_queue *q, const char *page, size_t count)
  41 {
  42         struct request_list *rl = &q->rq;
  43         unsigned long nr;
  44         int ret;
  45
  46         if (!q->request_fn)
  47                 return -EINVAL;
  48
  49         ret = queue_var_store(&nr, page, count);
  50         if (nr < BLKDEV_MIN_RQ)
  51                 nr = BLKDEV_MIN_RQ;
  52
  53         spin_lock_irq(q->queue_lock);
  54         q->nr_requests = nr;
  55         blk_queue_congestion_threshold(q);
  56
  57         if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
  58                 blk_set_queue_congested(q, BLK_RW_SYNC);
  59         else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
  60                 blk_clear_queue_congested(q, BLK_RW_SYNC);
  61
  62         if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
  63                 blk_set_queue_congested(q, BLK_RW_ASYNC);
  64         else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
  65                 blk_clear_queue_congested(q, BLK_RW_ASYNC);
  66
  67         if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
  68                 blk_set_queue_full(q, BLK_RW_SYNC);
  69         } else if (rl->count[BLK_RW_SYNC]+1 <= q->nr_requests) {
  70                 blk_clear_queue_full(q, BLK_RW_SYNC);
  71                 wake_up(&rl->wait[BLK_RW_SYNC]);
  72         }
  73
  74         if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
  75                 blk_set_queue_full(q, BLK_RW_ASYNC);
  76         } else if (rl->count[BLK_RW_ASYNC]+1 <= q->nr_requests) {
  77                 blk_clear_queue_full(q, BLK_RW_ASYNC);
  78                 wake_up(&rl->wait[BLK_RW_ASYNC]);
  79         }
  80         spin_unlock_irq(q->queue_lock);
  81         return ret;
  82 }
  83
  84 static ssize_t queue_ra_show(struct request_queue *q, char *page)
  85 {
  86         unsigned long ra_kb = q->backing_dev_info.ra_pages <<
  87                                         (PAGE_CACHE_SHIFT - 10);
  88
  89         return queue_var_show(ra_kb, (page));
  90 }
  91
  92 static ssize_t
  93 queue_ra_store(struct request_queue *q, const char *page, size_t count)
  94 {
  95         unsigned long ra_kb;
  96         ssize_t ret = queue_var_store(&ra_kb, page, count);
  97
  98         q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
  99
 100         return ret;
 101 }
 102
 103 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
 104 {
 105         int max_sectors_kb = queue_max_sectors(q) >> 1;
 106
 107         return queue_var_show(max_sectors_kb, (page));
 108 }
 109
 110 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
 111 {
 112         return queue_var_show(queue_max_segments(q), (page));
 113 }
 114
 115 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 116 {
 117         if (test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags))
 118                 return queue_var_show(queue_max_segment_size(q), (page));
 119
 120         return queue_var_show(PAGE_CACHE_SIZE, (page));
 121 }
 122
 123 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 124 {
 125         return queue_var_show(queue_logical_block_size(q), page);
 126 }
 127
 128 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 129 {
 130         return queue_var_show(queue_physical_block_size(q), page);
 131 }
 132
 133 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 134 {
 135         return queue_var_show(queue_io_min(q), page);
 136 }
 137
 138 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 139 {
 140         return queue_var_show(queue_io_opt(q), page);
 141 }
 142
 143 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 144 {
 145         return queue_var_show(q->limits.discard_granularity, page);
 146 }
 147
 148 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 149 {
 150         return queue_var_show(q->limits.max_discard_sectors << 9, page);
 151 }
 152
 153 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 154 {
 155         return queue_var_show(queue_discard_zeroes_data(q), page);
 156 }
 157
 158 static ssize_t
 159 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 160 {
 161         unsigned long max_sectors_kb,
 162                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 163                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
 164         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 165
 166         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 167                 return -EINVAL;
 168
 169         spin_lock_irq(q->queue_lock);
 170         q->limits.max_sectors = max_sectors_kb << 1;
 171         spin_unlock_irq(q->queue_lock);
 172
 173         return ret;
 174 }
 175
 176 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 177 {
 178         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 179
 180         return queue_var_show(max_hw_sectors_kb, (page));
 181 }
 182
 183 static ssize_t queue_nonrot_show(struct request_queue *q, char *page)
 184 {
 185         return queue_var_show(!blk_queue_nonrot(q), page);
 186 }
 187
 188 static ssize_t queue_nonrot_store(struct request_queue *q, const char *page,
 189                                   size_t count)
 190 {
 191         unsigned long nm;
 192         ssize_t ret = queue_var_store(&nm, page, count);
 193
 194         spin_lock_irq(q->queue_lock);
 195         if (nm)
 196                 queue_flag_clear(QUEUE_FLAG_NONROT, q);
 197         else
 198                 queue_flag_set(QUEUE_FLAG_NONROT, q);
 199         spin_unlock_irq(q->queue_lock);
 200
 201         return ret;
 202 }
 203
 204 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 205 {
 206         return queue_var_show((blk_queue_nomerges(q) << 1) |
 207                                blk_queue_noxmerges(q), page);
 208 }
 209
 210 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 211                                     size_t count)
 212 {
 213         unsigned long nm;
 214         ssize_t ret = queue_var_store(&nm, page, count);
 215
 216         spin_lock_irq(q->queue_lock);
 217         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 218         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 219         if (nm == 2)
 220                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 221         else if (nm)
 222                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 223         spin_unlock_irq(q->queue_lock);
 224
 225         return ret;
 226 }
 227
 228 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 229 {
 230         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 231
 232         return queue_var_show(set, page);
 233 }
 234
 235 static ssize_t
 236 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 237 {
 238         ssize_t ret = -EINVAL;
 239 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
 240         unsigned long val;
 241
 242         ret = queue_var_store(&val, page, count);
 243         spin_lock_irq(q->queue_lock);
 244         if (val)
 245                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 246         else
 247                 queue_flag_clear(QUEUE_FLAG_SAME_COMP,  q);
 248         spin_unlock_irq(q->queue_lock);
 249 #endif
 250         return ret;
 251 }
 252
 253 static ssize_t queue_random_show(struct request_queue *q, char *page)
 254 {
 255         return queue_var_show(blk_queue_add_random(q), page);
 256 }
 257
 258 static ssize_t queue_random_store(struct request_queue *q, const char *page,
 259                                   size_t count)
 260 {
 261         unsigned long val;
 262         ssize_t ret = queue_var_store(&val, page, count);
 263
 264         spin_lock_irq(q->queue_lock);
 265         if (val)
 266                 queue_flag_set(QUEUE_FLAG_ADD_RANDOM, q);
 267         else
 268                 queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, q);
 269         spin_unlock_irq(q->queue_lock);
 270
 271         return ret;
 272 }
 273
 274 static ssize_t queue_iostats_show(struct request_queue *q, char *page)
 275 {
 276         return queue_var_show(blk_queue_io_stat(q), page);
 277 }
 278
 279 static ssize_t queue_iostats_store(struct request_queue *q, const char *page,
 280                                    size_t count)
 281 {
 282         unsigned long stats;
 283         ssize_t ret = queue_var_store(&stats, page, count);
 284
 285         spin_lock_irq(q->queue_lock);
 286         if (stats)
 287                 queue_flag_set(QUEUE_FLAG_IO_STAT, q);
 288         else
 289                 queue_flag_clear(QUEUE_FLAG_IO_STAT, q);
 290         spin_unlock_irq(q->queue_lock);
 291
 292         return ret;
 293 }
 294
 295 static struct queue_sysfs_entry queue_requests_entry = {
 296         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 297         .show = queue_requests_show,
 298         .store = queue_requests_store,
 299 };
 300
 301 static struct queue_sysfs_entry queue_ra_entry = {
 302         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 303         .show = queue_ra_show,
 304         .store = queue_ra_store,
 305 };
 306
 307 static struct queue_sysfs_entry queue_max_sectors_entry = {
 308         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 309         .show = queue_max_sectors_show,
 310         .store = queue_max_sectors_store,
 311 };
 312
 313 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 314         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 315         .show = queue_max_hw_sectors_show,
 316 };
 317
 318 static struct queue_sysfs_entry queue_max_segments_entry = {
 319         .attr = {.name = "max_segments", .mode = S_IRUGO },
 320         .show = queue_max_segments_show,
 321 };
 322
 323 static struct queue_sysfs_entry queue_max_segment_size_entry = {
 324         .attr = {.name = "max_segment_size", .mode = S_IRUGO },
 325         .show = queue_max_segment_size_show,
 326 };
 327
 328 static struct queue_sysfs_entry queue_iosched_entry = {
 329         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 330         .show = elv_iosched_show,
 331         .store = elv_iosched_store,
 332 };
 333
 334 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 335         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 336         .show = queue_logical_block_size_show,
 337 };
 338
 339 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 340         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 341         .show = queue_logical_block_size_show,
 342 };
 343
 344 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 345         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 346         .show = queue_physical_block_size_show,
 347 };
 348
 349 static struct queue_sysfs_entry queue_io_min_entry = {
 350         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 351         .show = queue_io_min_show,
 352 };
 353
 354 static struct queue_sysfs_entry queue_io_opt_entry = {
 355         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 356         .show = queue_io_opt_show,
 357 };
 358
 359 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 360         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
 361         .show = queue_discard_granularity_show,
 362 };
 363
 364 static struct queue_sysfs_entry queue_discard_max_entry = {
 365         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
 366         .show = queue_discard_max_show,
 367 };
 368
 369 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 370         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
 371         .show = queue_discard_zeroes_data_show,
 372 };
 373
 374 static struct queue_sysfs_entry queue_nonrot_entry = {
 375         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 376         .show = queue_nonrot_show,
 377         .store = queue_nonrot_store,
 378 };
 379
 380 static struct queue_sysfs_entry queue_nomerges_entry = {
 381         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 382         .show = queue_nomerges_show,
 383         .store = queue_nomerges_store,
 384 };
 385
 386 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 387         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 388         .show = queue_rq_affinity_show,
 389         .store = queue_rq_affinity_store,
 390 };
 391
 392 static struct queue_sysfs_entry queue_iostats_entry = {
 393         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 394         .show = queue_iostats_show,
 395         .store = queue_iostats_store,
 396 };
 397
 398 static struct queue_sysfs_entry queue_random_entry = {
 399         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
 400         .show = queue_random_show,
 401         .store = queue_random_store,
 402 };
 403
 404 static struct attribute *default_attrs[] = {
 405         &queue_requests_entry.attr,
 406         &queue_ra_entry.attr,
 407         &queue_max_hw_sectors_entry.attr,
 408         &queue_max_sectors_entry.attr,
 409         &queue_max_segments_entry.attr,
 410         &queue_max_segment_size_entry.attr,
 411         &queue_iosched_entry.attr,
 412         &queue_hw_sector_size_entry.attr,
 413         &queue_logical_block_size_entry.attr,
 414         &queue_physical_block_size_entry.attr,
 415         &queue_io_min_entry.attr,
 416         &queue_io_opt_entry.attr,
 417         &queue_discard_granularity_entry.attr,
 418         &queue_discard_max_entry.attr,
 419         &queue_discard_zeroes_data_entry.attr,
 420         &queue_nonrot_entry.attr,
 421         &queue_nomerges_entry.attr,
 422         &queue_rq_affinity_entry.attr,
 423         &queue_iostats_entry.attr,
 424         &queue_random_entry.attr,
 425         NULL,
 426 };
 427
 428 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 429
 430 static ssize_t
 431 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 432 {
 433         struct queue_sysfs_entry *entry = to_queue(attr);
 434         struct request_queue *q =
 435                 container_of(kobj, struct request_queue, kobj);
 436         ssize_t res;
 437
 438         if (!entry->show)
 439                 return -EIO;
 440         mutex_lock(&q->sysfs_lock);
 441         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 442                 mutex_unlock(&q->sysfs_lock);
 443                 return -ENOENT;
 444         }
 445         res = entry->show(q, page);
 446         mutex_unlock(&q->sysfs_lock);
 447         return res;
 448 }
 449
 450 static ssize_t
 451 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 452                     const char *page, size_t length)
 453 {
 454         struct queue_sysfs_entry *entry = to_queue(attr);
 455         struct request_queue *q;
 456         ssize_t res;
 457
 458         if (!entry->store)
 459                 return -EIO;
 460
 461         q = container_of(kobj, struct request_queue, kobj);
 462         mutex_lock(&q->sysfs_lock);
 463         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 464                 mutex_unlock(&q->sysfs_lock);
 465                 return -ENOENT;
 466         }
 467         res = entry->store(q, page, length);
 468         mutex_unlock(&q->sysfs_lock);
 469         return res;
 470 }
 471
 472 /**
 473  * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
 474  * @kobj:    the kobj belonging of the request queue to be released
 475  *
 476  * Description:
 477  *     blk_cleanup_queue is the pair to blk_init_queue() or
 478  *     blk_queue_make_request().  It should be called when a request queue is
 479  *     being released; typically when a block device is being de-registered.
 480  *     Currently, its primary task it to free all the &struct request
 481  *     structures that were allocated to the queue and the queue itself.
 482  *
 483  * Caveat:
 484  *     Hopefully the low level driver will have finished any
 485  *     outstanding requests first...
 486  **/
 487 static void blk_release_queue(struct kobject *kobj)
 488 {
 489         struct request_queue *q =
 490                 container_of(kobj, struct request_queue, kobj);
 491         struct request_list *rl = &q->rq;
 492
 493         blk_sync_queue(q);
 494
 495         if (rl->rq_pool)
 496                 mempool_destroy(rl->rq_pool);
 497
 498         if (q->queue_tags)
 499                 __blk_queue_free_tags(q);
 500
 501         blk_trace_shutdown(q);
 502
 503         bdi_destroy(&q->backing_dev_info);
 504         kmem_cache_free(blk_requestq_cachep, q);
 505 }
 506
 507 static const struct sysfs_ops queue_sysfs_ops = {
 508         .show   = queue_attr_show,
 509         .store  = queue_attr_store,
 510 };
 511
 512 struct kobj_type blk_queue_ktype = {
 513         .sysfs_ops      = &queue_sysfs_ops,
 514         .default_attrs  = default_attrs,
 515         .release        = blk_release_queue,
 516 };
 517
 518 int blk_register_queue(struct gendisk *disk)
 519 {
 520         int ret;
 521         struct device *dev = disk_to_dev(disk);
 522
 523         struct request_queue *q = disk->queue;
 524
 525         if (WARN_ON(!q))
 526                 return -ENXIO;
 527
 528         ret = blk_trace_init_sysfs(dev);
 529         if (ret)
 530                 return ret;
 531
 532         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 533         if (ret < 0)
 534                 return ret;
 535
 536         kobject_uevent(&q->kobj, KOBJ_ADD);
 537
 538         if (!q->request_fn)
 539                 return 0;
 540
 541         ret = elv_register_queue(q);
 542         if (ret) {
 543                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 544                 kobject_del(&q->kobj);
 545                 blk_trace_remove_sysfs(disk_to_dev(disk));
 546                 return ret;
 547         }
 548
 549         return 0;
 550 }
 551
 552 void blk_unregister_queue(struct gendisk *disk)
 553 {
 554         struct request_queue *q = disk->queue;
 555
 556         if (WARN_ON(!q))
 557                 return;
 558
 559         if (q->request_fn)
 560                 elv_unregister_queue(q);
 561
 562         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 563         kobject_del(&q->kobj);
 564         blk_trace_remove_sysfs(disk_to_dev(disk));
 565         kobject_put(&disk_to_dev(disk)->kobj);
 566 }