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