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 #include "blk-cgroup.h"
  13
  14 struct queue_sysfs_entry {
  15         struct attribute attr;
  16         ssize_t (*show)(struct request_queue *, char *);
  17         ssize_t (*store)(struct request_queue *, const char *, size_t);
  18 };
  19
  20 static ssize_t
  21 queue_var_show(unsigned long var, char *page)
  22 {
  23         return sprintf(page, "%lu\n", var);
  24 }
  25
  26 static ssize_t
  27 queue_var_store(unsigned long *var, const char *page, size_t count)
  28 {
  29         int err;
  30         unsigned long v;
  31
  32         err = strict_strtoul(page, 10, &v);
  33         if (err || v > UINT_MAX)
  34                 return -EINVAL;
  35
  36         *var = v;
  37
  38         return count;
  39 }
  40
  41 static ssize_t queue_requests_show(struct request_queue *q, char *page)
  42 {
  43         return queue_var_show(q->nr_requests, (page));
  44 }
  45
  46 static ssize_t
  47 queue_requests_store(struct request_queue *q, const char *page, size_t count)
  48 {
  49         struct request_list *rl;
  50         unsigned long nr;
  51         int ret;
  52
  53         if (!q->request_fn)
  54                 return -EINVAL;
  55
  56         ret = queue_var_store(&nr, page, count);
  57         if (ret < 0)
  58                 return ret;
  59
  60         if (nr < BLKDEV_MIN_RQ)
  61                 nr = BLKDEV_MIN_RQ;
  62
  63         spin_lock_irq(q->queue_lock);
  64         q->nr_requests = nr;
  65         blk_queue_congestion_threshold(q);
  66
  67         /* congestion isn't cgroup aware and follows root blkcg for now */
  68         rl = &q->root_rl;
  69
  70         if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
  71                 blk_set_queue_congested(q, BLK_RW_SYNC);
  72         else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
  73                 blk_clear_queue_congested(q, BLK_RW_SYNC);
  74
  75         if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
  76                 blk_set_queue_congested(q, BLK_RW_ASYNC);
  77         else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
  78                 blk_clear_queue_congested(q, BLK_RW_ASYNC);
  79
  80         blk_queue_for_each_rl(rl, q) {
  81                 if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
  82                         blk_set_rl_full(rl, BLK_RW_SYNC);
  83                 } else {
  84                         blk_clear_rl_full(rl, BLK_RW_SYNC);
  85                         wake_up(&rl->wait[BLK_RW_SYNC]);
  86                 }
  87
  88                 if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
  89                         blk_set_rl_full(rl, BLK_RW_ASYNC);
  90                 } else {
  91                         blk_clear_rl_full(rl, BLK_RW_ASYNC);
  92                         wake_up(&rl->wait[BLK_RW_ASYNC]);
  93                 }
  94         }
  95
  96         spin_unlock_irq(q->queue_lock);
  97         return ret;
  98 }
  99
 100 static ssize_t queue_ra_show(struct request_queue *q, char *page)
 101 {
 102         unsigned long ra_kb = q->backing_dev_info.ra_pages <<
 103                                         (PAGE_CACHE_SHIFT - 10);
 104
 105         return queue_var_show(ra_kb, (page));
 106 }
 107
 108 static ssize_t
 109 queue_ra_store(struct request_queue *q, const char *page, size_t count)
 110 {
 111         unsigned long ra_kb;
 112         ssize_t ret = queue_var_store(&ra_kb, page, count);
 113
 114         if (ret < 0)
 115                 return ret;
 116
 117         q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
 118
 119         return ret;
 120 }
 121
 122 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
 123 {
 124         int max_sectors_kb = queue_max_sectors(q) >> 1;
 125
 126         return queue_var_show(max_sectors_kb, (page));
 127 }
 128
 129 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
 130 {
 131         return queue_var_show(queue_max_segments(q), (page));
 132 }
 133
 134 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
 135 {
 136         return queue_var_show(q->limits.max_integrity_segments, (page));
 137 }
 138
 139 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 140 {
 141         if (blk_queue_cluster(q))
 142                 return queue_var_show(queue_max_segment_size(q), (page));
 143
 144         return queue_var_show(PAGE_CACHE_SIZE, (page));
 145 }
 146
 147 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 148 {
 149         return queue_var_show(queue_logical_block_size(q), page);
 150 }
 151
 152 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 153 {
 154         return queue_var_show(queue_physical_block_size(q), page);
 155 }
 156
 157 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 158 {
 159         return queue_var_show(queue_io_min(q), page);
 160 }
 161
 162 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 163 {
 164         return queue_var_show(queue_io_opt(q), page);
 165 }
 166
 167 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 168 {
 169         return queue_var_show(q->limits.discard_granularity, page);
 170 }
 171
 172 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 173 {
 174         return sprintf(page, "%llu\n",
 175                        (unsigned long long)q->limits.max_discard_sectors << 9);
 176 }
 177
 178 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 179 {
 180         return queue_var_show(queue_discard_zeroes_data(q), page);
 181 }
 182
 183 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
 184 {
 185         return sprintf(page, "%llu\n",
 186                 (unsigned long long)q->limits.max_write_same_sectors << 9);
 187 }
 188
 189
 190 static ssize_t
 191 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 192 {
 193         unsigned long max_sectors_kb,
 194                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 195                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
 196         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 197
 198         if (ret < 0)
 199                 return ret;
 200
 201         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 202                 return -EINVAL;
 203
 204         spin_lock_irq(q->queue_lock);
 205         q->limits.max_sectors = max_sectors_kb << 1;
 206         spin_unlock_irq(q->queue_lock);
 207
 208         return ret;
 209 }
 210
 211 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 212 {
 213         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 214
 215         return queue_var_show(max_hw_sectors_kb, (page));
 216 }
 217
 218 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 219 static ssize_t                                                          \
 220 queue_show_##name(struct request_queue *q, char *page)                  \
 221 {                                                                       \
 222         int bit;                                                        \
 223         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 224         return queue_var_show(neg ? !bit : bit, page);                  \
 225 }                                                                       \
 226 static ssize_t                                                          \
 227 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
 228 {                                                                       \
 229         unsigned long val;                                              \
 230         ssize_t ret;                                                    \
 231         ret = queue_var_store(&val, page, count);                       \
 232         if (ret < 0)                                                    \
 233                  return ret;                                            \
 234         if (neg)                                                        \
 235                 val = !val;                                             \
 236                                                                         \
 237         spin_lock_irq(q->queue_lock);                                   \
 238         if (val)                                                        \
 239                 queue_flag_set(QUEUE_FLAG_##flag, q);                   \
 240         else                                                            \
 241                 queue_flag_clear(QUEUE_FLAG_##flag, q);                 \
 242         spin_unlock_irq(q->queue_lock);                                 \
 243         return ret;                                                     \
 244 }
 245
 246 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 247 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 248 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 249 #undef QUEUE_SYSFS_BIT_FNS
 250
 251 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 252 {
 253         return queue_var_show((blk_queue_nomerges(q) << 1) |
 254                                blk_queue_noxmerges(q), page);
 255 }
 256
 257 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 258                                     size_t count)
 259 {
 260         unsigned long nm;
 261         ssize_t ret = queue_var_store(&nm, page, count);
 262
 263         if (ret < 0)
 264                 return ret;
 265
 266         spin_lock_irq(q->queue_lock);
 267         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 268         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 269         if (nm == 2)
 270                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 271         else if (nm)
 272                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 273         spin_unlock_irq(q->queue_lock);
 274
 275         return ret;
 276 }
 277
 278 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 279 {
 280         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 281         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 282
 283         return queue_var_show(set << force, page);
 284 }
 285
 286 static ssize_t
 287 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 288 {
 289         ssize_t ret = -EINVAL;
 290 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
 291         unsigned long val;
 292
 293         ret = queue_var_store(&val, page, count);
 294         if (ret < 0)
 295                 return ret;
 296
 297         spin_lock_irq(q->queue_lock);
 298         if (val == 2) {
 299                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 300                 queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 301         } else if (val == 1) {
 302                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 303                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 304         } else if (val == 0) {
 305                 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 306                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 307         }
 308         spin_unlock_irq(q->queue_lock);
 309 #endif
 310         return ret;
 311 }
 312
 313 static struct queue_sysfs_entry queue_requests_entry = {
 314         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 315         .show = queue_requests_show,
 316         .store = queue_requests_store,
 317 };
 318
 319 static struct queue_sysfs_entry queue_ra_entry = {
 320         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 321         .show = queue_ra_show,
 322         .store = queue_ra_store,
 323 };
 324
 325 static struct queue_sysfs_entry queue_max_sectors_entry = {
 326         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 327         .show = queue_max_sectors_show,
 328         .store = queue_max_sectors_store,
 329 };
 330
 331 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 332         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 333         .show = queue_max_hw_sectors_show,
 334 };
 335
 336 static struct queue_sysfs_entry queue_max_segments_entry = {
 337         .attr = {.name = "max_segments", .mode = S_IRUGO },
 338         .show = queue_max_segments_show,
 339 };
 340
 341 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
 342         .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
 343         .show = queue_max_integrity_segments_show,
 344 };
 345
 346 static struct queue_sysfs_entry queue_max_segment_size_entry = {
 347         .attr = {.name = "max_segment_size", .mode = S_IRUGO },
 348         .show = queue_max_segment_size_show,
 349 };
 350
 351 static struct queue_sysfs_entry queue_iosched_entry = {
 352         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 353         .show = elv_iosched_show,
 354         .store = elv_iosched_store,
 355 };
 356
 357 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 358         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 359         .show = queue_logical_block_size_show,
 360 };
 361
 362 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 363         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 364         .show = queue_logical_block_size_show,
 365 };
 366
 367 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 368         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 369         .show = queue_physical_block_size_show,
 370 };
 371
 372 static struct queue_sysfs_entry queue_io_min_entry = {
 373         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 374         .show = queue_io_min_show,
 375 };
 376
 377 static struct queue_sysfs_entry queue_io_opt_entry = {
 378         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 379         .show = queue_io_opt_show,
 380 };
 381
 382 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 383         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
 384         .show = queue_discard_granularity_show,
 385 };
 386
 387 static struct queue_sysfs_entry queue_discard_max_entry = {
 388         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
 389         .show = queue_discard_max_show,
 390 };
 391
 392 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 393         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
 394         .show = queue_discard_zeroes_data_show,
 395 };
 396
 397 static struct queue_sysfs_entry queue_write_same_max_entry = {
 398         .attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
 399         .show = queue_write_same_max_show,
 400 };
 401
 402 static struct queue_sysfs_entry queue_nonrot_entry = {
 403         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 404         .show = queue_show_nonrot,
 405         .store = queue_store_nonrot,
 406 };
 407
 408 static struct queue_sysfs_entry queue_nomerges_entry = {
 409         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 410         .show = queue_nomerges_show,
 411         .store = queue_nomerges_store,
 412 };
 413
 414 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 415         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 416         .show = queue_rq_affinity_show,
 417         .store = queue_rq_affinity_store,
 418 };
 419
 420 static struct queue_sysfs_entry queue_iostats_entry = {
 421         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 422         .show = queue_show_iostats,
 423         .store = queue_store_iostats,
 424 };
 425
 426 static struct queue_sysfs_entry queue_random_entry = {
 427         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
 428         .show = queue_show_random,
 429         .store = queue_store_random,
 430 };
 431
 432 static struct attribute *default_attrs[] = {
 433         &queue_requests_entry.attr,
 434         &queue_ra_entry.attr,
 435         &queue_max_hw_sectors_entry.attr,
 436         &queue_max_sectors_entry.attr,
 437         &queue_max_segments_entry.attr,
 438         &queue_max_integrity_segments_entry.attr,
 439         &queue_max_segment_size_entry.attr,
 440         &queue_iosched_entry.attr,
 441         &queue_hw_sector_size_entry.attr,
 442         &queue_logical_block_size_entry.attr,
 443         &queue_physical_block_size_entry.attr,
 444         &queue_io_min_entry.attr,
 445         &queue_io_opt_entry.attr,
 446         &queue_discard_granularity_entry.attr,
 447         &queue_discard_max_entry.attr,
 448         &queue_discard_zeroes_data_entry.attr,
 449         &queue_write_same_max_entry.attr,
 450         &queue_nonrot_entry.attr,
 451         &queue_nomerges_entry.attr,
 452         &queue_rq_affinity_entry.attr,
 453         &queue_iostats_entry.attr,
 454         &queue_random_entry.attr,
 455         NULL,
 456 };
 457
 458 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 459
 460 static ssize_t
 461 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 462 {
 463         struct queue_sysfs_entry *entry = to_queue(attr);
 464         struct request_queue *q =
 465                 container_of(kobj, struct request_queue, kobj);
 466         ssize_t res;
 467
 468         if (!entry->show)
 469                 return -EIO;
 470         mutex_lock(&q->sysfs_lock);
 471         if (blk_queue_dying(q)) {
 472                 mutex_unlock(&q->sysfs_lock);
 473                 return -ENOENT;
 474         }
 475         res = entry->show(q, page);
 476         mutex_unlock(&q->sysfs_lock);
 477         return res;
 478 }
 479
 480 static ssize_t
 481 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 482                     const char *page, size_t length)
 483 {
 484         struct queue_sysfs_entry *entry = to_queue(attr);
 485         struct request_queue *q;
 486         ssize_t res;
 487
 488         if (!entry->store)
 489                 return -EIO;
 490
 491         q = container_of(kobj, struct request_queue, kobj);
 492         mutex_lock(&q->sysfs_lock);
 493         if (blk_queue_dying(q)) {
 494                 mutex_unlock(&q->sysfs_lock);
 495                 return -ENOENT;
 496         }
 497         res = entry->store(q, page, length);
 498         mutex_unlock(&q->sysfs_lock);
 499         return res;
 500 }
 501
 502 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 503 {
 504         struct request_queue *q = container_of(rcu_head, struct request_queue,
 505                                                rcu_head);
 506         kmem_cache_free(blk_requestq_cachep, q);
 507 }
 508
 509 /**
 510  * blk_release_queue: - release a &struct request_queue when it is no longer needed
 511  * @kobj:    the kobj belonging to the request queue to be released
 512  *
 513  * Description:
 514  *     blk_release_queue is the pair to blk_init_queue() or
 515  *     blk_queue_make_request().  It should be called when a request queue is
 516  *     being released; typically when a block device is being de-registered.
 517  *     Currently, its primary task it to free all the &struct request
 518  *     structures that were allocated to the queue and the queue itself.
 519  *
 520  * Caveat:
 521  *     Hopefully the low level driver will have finished any
 522  *     outstanding requests first...
 523  **/
 524 static void blk_release_queue(struct kobject *kobj)
 525 {
 526         struct request_queue *q =
 527                 container_of(kobj, struct request_queue, kobj);
 528
 529         blk_sync_queue(q);
 530
 531         blkcg_exit_queue(q);
 532
 533         if (q->elevator) {
 534                 spin_lock_irq(q->queue_lock);
 535                 ioc_clear_queue(q);
 536                 spin_unlock_irq(q->queue_lock);
 537                 elevator_exit(q->elevator);
 538         }
 539
 540         blk_exit_rl(&q->root_rl);
 541
 542         if (q->queue_tags)
 543                 __blk_queue_free_tags(q);
 544
 545         blk_trace_shutdown(q);
 546
 547         bdi_destroy(&q->backing_dev_info);
 548
 549         ida_simple_remove(&blk_queue_ida, q->id);
 550         call_rcu(&q->rcu_head, blk_free_queue_rcu);
 551 }
 552
 553 static const struct sysfs_ops queue_sysfs_ops = {
 554         .show   = queue_attr_show,
 555         .store  = queue_attr_store,
 556 };
 557
 558 struct kobj_type blk_queue_ktype = {
 559         .sysfs_ops      = &queue_sysfs_ops,
 560         .default_attrs  = default_attrs,
 561         .release        = blk_release_queue,
 562 };
 563
 564 int blk_register_queue(struct gendisk *disk)
 565 {
 566         int ret;
 567         struct device *dev = disk_to_dev(disk);
 568         struct request_queue *q = disk->queue;
 569
 570         if (WARN_ON(!q))
 571                 return -ENXIO;
 572
 573         /*
 574          * Initialization must be complete by now.  Finish the initial
 575          * bypass from queue allocation.
 576          */
 577         blk_queue_bypass_end(q);
 578
 579         ret = blk_trace_init_sysfs(dev);
 580         if (ret)
 581                 return ret;
 582
 583         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 584         if (ret < 0) {
 585                 blk_trace_remove_sysfs(dev);
 586                 return ret;
 587         }
 588
 589         kobject_uevent(&q->kobj, KOBJ_ADD);
 590
 591         if (!q->request_fn)
 592                 return 0;
 593
 594         ret = elv_register_queue(q);
 595         if (ret) {
 596                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 597                 kobject_del(&q->kobj);
 598                 blk_trace_remove_sysfs(dev);
 599                 kobject_put(&dev->kobj);
 600                 return ret;
 601         }
 602
 603         return 0;
 604 }
 605
 606 void blk_unregister_queue(struct gendisk *disk)
 607 {
 608         struct request_queue *q = disk->queue;
 609
 610         if (WARN_ON(!q))
 611                 return;
 612
 613         if (q->request_fn)
 614                 elv_unregister_queue(q);
 615
 616         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 617         kobject_del(&q->kobj);
 618         blk_trace_remove_sysfs(disk_to_dev(disk));
 619         kobject_put(&disk_to_dev(disk)->kobj);
 620 }