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 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 184 static ssize_t                                                          \
 185 queue_show_##name(struct request_queue *q, char *page)                  \
 186 {                                                                       \
 187         int bit;                                                        \
 188         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 189         return queue_var_show(neg ? !bit : bit, page);                  \
 190 }                                                                       \
 191 static ssize_t                                                          \
 192 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
 193 {                                                                       \
 194         unsigned long val;                                              \
 195         ssize_t ret;                                                    \
 196         ret = queue_var_store(&val, page, count);                       \
 197         if (neg)                                                        \
 198                 val = !val;                                             \
 199                                                                         \
 200         spin_lock_irq(q->queue_lock);                                   \
 201         if (val)                                                        \
 202                 queue_flag_set(QUEUE_FLAG_##flag, q);                   \
 203         else                                                            \
 204                 queue_flag_clear(QUEUE_FLAG_##flag, q);                 \
 205         spin_unlock_irq(q->queue_lock);                                 \
 206         return ret;                                                     \
 207 }
 208
 209 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 210 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 211 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 212 #undef QUEUE_SYSFS_BIT_FNS
 213
 214 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 215 {
 216         return queue_var_show((blk_queue_nomerges(q) << 1) |
 217                                blk_queue_noxmerges(q), page);
 218 }
 219
 220 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 221                                     size_t count)
 222 {
 223         unsigned long nm;
 224         ssize_t ret = queue_var_store(&nm, page, count);
 225
 226         spin_lock_irq(q->queue_lock);
 227         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 228         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 229         if (nm == 2)
 230                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 231         else if (nm)
 232                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 233         spin_unlock_irq(q->queue_lock);
 234
 235         return ret;
 236 }
 237
 238 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 239 {
 240         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 241
 242         return queue_var_show(set, page);
 243 }
 244
 245 static ssize_t
 246 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 247 {
 248         ssize_t ret = -EINVAL;
 249 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
 250         unsigned long val;
 251
 252         ret = queue_var_store(&val, page, count);
 253         spin_lock_irq(q->queue_lock);
 254         if (val)
 255                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 256         else
 257                 queue_flag_clear(QUEUE_FLAG_SAME_COMP,  q);
 258         spin_unlock_irq(q->queue_lock);
 259 #endif
 260         return ret;
 261 }
 262
 263 static struct queue_sysfs_entry queue_requests_entry = {
 264         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 265         .show = queue_requests_show,
 266         .store = queue_requests_store,
 267 };
 268
 269 static struct queue_sysfs_entry queue_ra_entry = {
 270         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 271         .show = queue_ra_show,
 272         .store = queue_ra_store,
 273 };
 274
 275 static struct queue_sysfs_entry queue_max_sectors_entry = {
 276         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 277         .show = queue_max_sectors_show,
 278         .store = queue_max_sectors_store,
 279 };
 280
 281 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 282         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 283         .show = queue_max_hw_sectors_show,
 284 };
 285
 286 static struct queue_sysfs_entry queue_max_segments_entry = {
 287         .attr = {.name = "max_segments", .mode = S_IRUGO },
 288         .show = queue_max_segments_show,
 289 };
 290
 291 static struct queue_sysfs_entry queue_max_segment_size_entry = {
 292         .attr = {.name = "max_segment_size", .mode = S_IRUGO },
 293         .show = queue_max_segment_size_show,
 294 };
 295
 296 static struct queue_sysfs_entry queue_iosched_entry = {
 297         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 298         .show = elv_iosched_show,
 299         .store = elv_iosched_store,
 300 };
 301
 302 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 303         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 304         .show = queue_logical_block_size_show,
 305 };
 306
 307 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 308         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 309         .show = queue_logical_block_size_show,
 310 };
 311
 312 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 313         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 314         .show = queue_physical_block_size_show,
 315 };
 316
 317 static struct queue_sysfs_entry queue_io_min_entry = {
 318         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 319         .show = queue_io_min_show,
 320 };
 321
 322 static struct queue_sysfs_entry queue_io_opt_entry = {
 323         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 324         .show = queue_io_opt_show,
 325 };
 326
 327 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 328         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
 329         .show = queue_discard_granularity_show,
 330 };
 331
 332 static struct queue_sysfs_entry queue_discard_max_entry = {
 333         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
 334         .show = queue_discard_max_show,
 335 };
 336
 337 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 338         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
 339         .show = queue_discard_zeroes_data_show,
 340 };
 341
 342 static struct queue_sysfs_entry queue_nonrot_entry = {
 343         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 344         .show = queue_show_nonrot,
 345         .store = queue_store_nonrot,
 346 };
 347
 348 static struct queue_sysfs_entry queue_nomerges_entry = {
 349         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 350         .show = queue_nomerges_show,
 351         .store = queue_nomerges_store,
 352 };
 353
 354 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 355         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 356         .show = queue_rq_affinity_show,
 357         .store = queue_rq_affinity_store,
 358 };
 359
 360 static struct queue_sysfs_entry queue_iostats_entry = {
 361         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 362         .show = queue_show_iostats,
 363         .store = queue_store_iostats,
 364 };
 365
 366 static struct queue_sysfs_entry queue_random_entry = {
 367         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
 368         .show = queue_show_random,
 369         .store = queue_store_random,
 370 };
 371
 372 static struct attribute *default_attrs[] = {
 373         &queue_requests_entry.attr,
 374         &queue_ra_entry.attr,
 375         &queue_max_hw_sectors_entry.attr,
 376         &queue_max_sectors_entry.attr,
 377         &queue_max_segments_entry.attr,
 378         &queue_max_segment_size_entry.attr,
 379         &queue_iosched_entry.attr,
 380         &queue_hw_sector_size_entry.attr,
 381         &queue_logical_block_size_entry.attr,
 382         &queue_physical_block_size_entry.attr,
 383         &queue_io_min_entry.attr,
 384         &queue_io_opt_entry.attr,
 385         &queue_discard_granularity_entry.attr,
 386         &queue_discard_max_entry.attr,
 387         &queue_discard_zeroes_data_entry.attr,
 388         &queue_nonrot_entry.attr,
 389         &queue_nomerges_entry.attr,
 390         &queue_rq_affinity_entry.attr,
 391         &queue_iostats_entry.attr,
 392         &queue_random_entry.attr,
 393         NULL,
 394 };
 395
 396 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 397
 398 static ssize_t
 399 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 400 {
 401         struct queue_sysfs_entry *entry = to_queue(attr);
 402         struct request_queue *q =
 403                 container_of(kobj, struct request_queue, kobj);
 404         ssize_t res;
 405
 406         if (!entry->show)
 407                 return -EIO;
 408         mutex_lock(&q->sysfs_lock);
 409         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 410                 mutex_unlock(&q->sysfs_lock);
 411                 return -ENOENT;
 412         }
 413         res = entry->show(q, page);
 414         mutex_unlock(&q->sysfs_lock);
 415         return res;
 416 }
 417
 418 static ssize_t
 419 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 420                     const char *page, size_t length)
 421 {
 422         struct queue_sysfs_entry *entry = to_queue(attr);
 423         struct request_queue *q;
 424         ssize_t res;
 425
 426         if (!entry->store)
 427                 return -EIO;
 428
 429         q = container_of(kobj, struct request_queue, kobj);
 430         mutex_lock(&q->sysfs_lock);
 431         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 432                 mutex_unlock(&q->sysfs_lock);
 433                 return -ENOENT;
 434         }
 435         res = entry->store(q, page, length);
 436         mutex_unlock(&q->sysfs_lock);
 437         return res;
 438 }
 439
 440 /**
 441  * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
 442  * @kobj:    the kobj belonging of the request queue to be released
 443  *
 444  * Description:
 445  *     blk_cleanup_queue is the pair to blk_init_queue() or
 446  *     blk_queue_make_request().  It should be called when a request queue is
 447  *     being released; typically when a block device is being de-registered.
 448  *     Currently, its primary task it to free all the &struct request
 449  *     structures that were allocated to the queue and the queue itself.
 450  *
 451  * Caveat:
 452  *     Hopefully the low level driver will have finished any
 453  *     outstanding requests first...
 454  **/
 455 static void blk_release_queue(struct kobject *kobj)
 456 {
 457         struct request_queue *q =
 458                 container_of(kobj, struct request_queue, kobj);
 459         struct request_list *rl = &q->rq;
 460
 461         blk_sync_queue(q);
 462
 463         if (rl->rq_pool)
 464                 mempool_destroy(rl->rq_pool);
 465
 466         if (q->queue_tags)
 467                 __blk_queue_free_tags(q);
 468
 469         blk_trace_shutdown(q);
 470
 471         bdi_destroy(&q->backing_dev_info);
 472         kmem_cache_free(blk_requestq_cachep, q);
 473 }
 474
 475 static const struct sysfs_ops queue_sysfs_ops = {
 476         .show   = queue_attr_show,
 477         .store  = queue_attr_store,
 478 };
 479
 480 struct kobj_type blk_queue_ktype = {
 481         .sysfs_ops      = &queue_sysfs_ops,
 482         .default_attrs  = default_attrs,
 483         .release        = blk_release_queue,
 484 };
 485
 486 int blk_register_queue(struct gendisk *disk)
 487 {
 488         int ret;
 489         struct device *dev = disk_to_dev(disk);
 490
 491         struct request_queue *q = disk->queue;
 492
 493         if (WARN_ON(!q))
 494                 return -ENXIO;
 495
 496         ret = blk_trace_init_sysfs(dev);
 497         if (ret)
 498                 return ret;
 499
 500         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 501         if (ret < 0)
 502                 return ret;
 503
 504         kobject_uevent(&q->kobj, KOBJ_ADD);
 505
 506         if (!q->request_fn)
 507                 return 0;
 508
 509         ret = elv_register_queue(q);
 510         if (ret) {
 511                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 512                 kobject_del(&q->kobj);
 513                 blk_trace_remove_sysfs(disk_to_dev(disk));
 514                 kobject_put(&dev->kobj);
 515                 return ret;
 516         }
 517
 518         return 0;
 519 }
 520
 521 void blk_unregister_queue(struct gendisk *disk)
 522 {
 523         struct request_queue *q = disk->queue;
 524
 525         if (WARN_ON(!q))
 526                 return;
 527
 528         if (q->request_fn)
 529                 elv_unregister_queue(q);
 530
 531         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 532         kobject_del(&q->kobj);
 533         blk_trace_remove_sysfs(disk_to_dev(disk));
 534         kobject_put(&disk_to_dev(disk)->kobj);
 535 }