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 #include <linux/blk-mq.h>
  11
  12 #include "blk.h"
  13 #include "blk-cgroup.h"
  14
  15 struct queue_sysfs_entry {
  16         struct attribute attr;
  17         ssize_t (*show)(struct request_queue *, char *);
  18         ssize_t (*store)(struct request_queue *, const char *, size_t);
  19 };
  20
  21 static ssize_t
  22 queue_var_show(unsigned long var, char *page)
  23 {
  24         return sprintf(page, "%lu\n", var);
  25 }
  26
  27 static ssize_t
  28 queue_var_store(unsigned long *var, const char *page, size_t count)
  29 {
  30         int err;
  31         unsigned long v;
  32
  33         err = kstrtoul(page, 10, &v);
  34         if (err || v > UINT_MAX)
  35                 return -EINVAL;
  36
  37         *var = v;
  38
  39         return count;
  40 }
  41
  42 static ssize_t queue_requests_show(struct request_queue *q, char *page)
  43 {
  44         return queue_var_show(q->nr_requests, (page));
  45 }
  46
  47 static ssize_t
  48 queue_requests_store(struct request_queue *q, const char *page, size_t count)
  49 {
  50         struct request_list *rl;
  51         unsigned long nr;
  52         int ret;
  53
  54         if (!q->request_fn)
  55                 return -EINVAL;
  56
  57         ret = queue_var_store(&nr, page, count);
  58         if (ret < 0)
  59                 return ret;
  60
  61         if (nr < BLKDEV_MIN_RQ)
  62                 nr = BLKDEV_MIN_RQ;
  63
  64         spin_lock_irq(q->queue_lock);
  65         q->nr_requests = nr;
  66         blk_queue_congestion_threshold(q);
  67
  68         /* congestion isn't cgroup aware and follows root blkcg for now */
  69         rl = &q->root_rl;
  70
  71         if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
  72                 blk_set_queue_congested(q, BLK_RW_SYNC);
  73         else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
  74                 blk_clear_queue_congested(q, BLK_RW_SYNC);
  75
  76         if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
  77                 blk_set_queue_congested(q, BLK_RW_ASYNC);
  78         else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
  79                 blk_clear_queue_congested(q, BLK_RW_ASYNC);
  80
  81         blk_queue_for_each_rl(rl, q) {
  82                 if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
  83                         blk_set_rl_full(rl, BLK_RW_SYNC);
  84                 } else {
  85                         blk_clear_rl_full(rl, BLK_RW_SYNC);
  86                         wake_up(&rl->wait[BLK_RW_SYNC]);
  87                 }
  88
  89                 if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
  90                         blk_set_rl_full(rl, BLK_RW_ASYNC);
  91                 } else {
  92                         blk_clear_rl_full(rl, BLK_RW_ASYNC);
  93                         wake_up(&rl->wait[BLK_RW_ASYNC]);
  94                 }
  95         }
  96
  97         spin_unlock_irq(q->queue_lock);
  98         return ret;
  99 }
 100
 101 static ssize_t queue_ra_show(struct request_queue *q, char *page)
 102 {
 103         unsigned long ra_kb = q->backing_dev_info.ra_pages <<
 104                                         (PAGE_CACHE_SHIFT - 10);
 105
 106         return queue_var_show(ra_kb, (page));
 107 }
 108
 109 static ssize_t
 110 queue_ra_store(struct request_queue *q, const char *page, size_t count)
 111 {
 112         unsigned long ra_kb;
 113         ssize_t ret = queue_var_store(&ra_kb, page, count);
 114
 115         if (ret < 0)
 116                 return ret;
 117
 118         q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
 119
 120         return ret;
 121 }
 122
 123 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
 124 {
 125         int max_sectors_kb = queue_max_sectors(q) >> 1;
 126
 127         return queue_var_show(max_sectors_kb, (page));
 128 }
 129
 130 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
 131 {
 132         return queue_var_show(queue_max_segments(q), (page));
 133 }
 134
 135 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
 136 {
 137         return queue_var_show(q->limits.max_integrity_segments, (page));
 138 }
 139
 140 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 141 {
 142         if (blk_queue_cluster(q))
 143                 return queue_var_show(queue_max_segment_size(q), (page));
 144
 145         return queue_var_show(PAGE_CACHE_SIZE, (page));
 146 }
 147
 148 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 149 {
 150         return queue_var_show(queue_logical_block_size(q), page);
 151 }
 152
 153 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 154 {
 155         return queue_var_show(queue_physical_block_size(q), page);
 156 }
 157
 158 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 159 {
 160         return queue_var_show(queue_io_min(q), page);
 161 }
 162
 163 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 164 {
 165         return queue_var_show(queue_io_opt(q), page);
 166 }
 167
 168 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 169 {
 170         return queue_var_show(q->limits.discard_granularity, page);
 171 }
 172
 173 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 174 {
 175         return sprintf(page, "%llu\n",
 176                        (unsigned long long)q->limits.max_discard_sectors << 9);
 177 }
 178
 179 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 180 {
 181         return queue_var_show(queue_discard_zeroes_data(q), page);
 182 }
 183
 184 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
 185 {
 186         return sprintf(page, "%llu\n",
 187                 (unsigned long long)q->limits.max_write_same_sectors << 9);
 188 }
 189
 190
 191 static ssize_t
 192 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 193 {
 194         unsigned long max_sectors_kb,
 195                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 196                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
 197         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 198
 199         if (ret < 0)
 200                 return ret;
 201
 202         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 203                 return -EINVAL;
 204
 205         spin_lock_irq(q->queue_lock);
 206         q->limits.max_sectors = max_sectors_kb << 1;
 207         spin_unlock_irq(q->queue_lock);
 208
 209         return ret;
 210 }
 211
 212 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 213 {
 214         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 215
 216         return queue_var_show(max_hw_sectors_kb, (page));
 217 }
 218
 219 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 220 static ssize_t                                                          \
 221 queue_show_##name(struct request_queue *q, char *page)                  \
 222 {                                                                       \
 223         int bit;                                                        \
 224         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 225         return queue_var_show(neg ? !bit : bit, page);                  \
 226 }                                                                       \
 227 static ssize_t                                                          \
 228 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
 229 {                                                                       \
 230         unsigned long val;                                              \
 231         ssize_t ret;                                                    \
 232         ret = queue_var_store(&val, page, count);                       \
 233         if (ret < 0)                                                    \
 234                  return ret;                                            \
 235         if (neg)                                                        \
 236                 val = !val;                                             \
 237                                                                         \
 238         spin_lock_irq(q->queue_lock);                                   \
 239         if (val)                                                        \
 240                 queue_flag_set(QUEUE_FLAG_##flag, q);                   \
 241         else                                                            \
 242                 queue_flag_clear(QUEUE_FLAG_##flag, q);                 \
 243         spin_unlock_irq(q->queue_lock);                                 \
 244         return ret;                                                     \
 245 }
 246
 247 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 248 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 249 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 250 #undef QUEUE_SYSFS_BIT_FNS
 251
 252 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 253 {
 254         return queue_var_show((blk_queue_nomerges(q) << 1) |
 255                                blk_queue_noxmerges(q), page);
 256 }
 257
 258 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 259                                     size_t count)
 260 {
 261         unsigned long nm;
 262         ssize_t ret = queue_var_store(&nm, page, count);
 263
 264         if (ret < 0)
 265                 return ret;
 266
 267         spin_lock_irq(q->queue_lock);
 268         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 269         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 270         if (nm == 2)
 271                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 272         else if (nm)
 273                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 274         spin_unlock_irq(q->queue_lock);
 275
 276         return ret;
 277 }
 278
 279 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 280 {
 281         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 282         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 283
 284         return queue_var_show(set << force, page);
 285 }
 286
 287 static ssize_t
 288 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 289 {
 290         ssize_t ret = -EINVAL;
 291 #ifdef CONFIG_SMP
 292         unsigned long val;
 293
 294         ret = queue_var_store(&val, page, count);
 295         if (ret < 0)
 296                 return ret;
 297
 298         spin_lock_irq(q->queue_lock);
 299         if (val == 2) {
 300                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 301                 queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 302         } else if (val == 1) {
 303                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 304                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 305         } else if (val == 0) {
 306                 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 307                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 308         }
 309         spin_unlock_irq(q->queue_lock);
 310 #endif
 311         return ret;
 312 }
 313
 314 static struct queue_sysfs_entry queue_requests_entry = {
 315         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 316         .show = queue_requests_show,
 317         .store = queue_requests_store,
 318 };
 319
 320 static struct queue_sysfs_entry queue_ra_entry = {
 321         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 322         .show = queue_ra_show,
 323         .store = queue_ra_store,
 324 };
 325
 326 static struct queue_sysfs_entry queue_max_sectors_entry = {
 327         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 328         .show = queue_max_sectors_show,
 329         .store = queue_max_sectors_store,
 330 };
 331
 332 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 333         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 334         .show = queue_max_hw_sectors_show,
 335 };
 336
 337 static struct queue_sysfs_entry queue_max_segments_entry = {
 338         .attr = {.name = "max_segments", .mode = S_IRUGO },
 339         .show = queue_max_segments_show,
 340 };
 341
 342 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
 343         .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
 344         .show = queue_max_integrity_segments_show,
 345 };
 346
 347 static struct queue_sysfs_entry queue_max_segment_size_entry = {
 348         .attr = {.name = "max_segment_size", .mode = S_IRUGO },
 349         .show = queue_max_segment_size_show,
 350 };
 351
 352 static struct queue_sysfs_entry queue_iosched_entry = {
 353         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 354         .show = elv_iosched_show,
 355         .store = elv_iosched_store,
 356 };
 357
 358 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 359         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 360         .show = queue_logical_block_size_show,
 361 };
 362
 363 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 364         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 365         .show = queue_logical_block_size_show,
 366 };
 367
 368 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 369         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 370         .show = queue_physical_block_size_show,
 371 };
 372
 373 static struct queue_sysfs_entry queue_io_min_entry = {
 374         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 375         .show = queue_io_min_show,
 376 };
 377
 378 static struct queue_sysfs_entry queue_io_opt_entry = {
 379         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 380         .show = queue_io_opt_show,
 381 };
 382
 383 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 384         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
 385         .show = queue_discard_granularity_show,
 386 };
 387
 388 static struct queue_sysfs_entry queue_discard_max_entry = {
 389         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
 390         .show = queue_discard_max_show,
 391 };
 392
 393 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 394         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
 395         .show = queue_discard_zeroes_data_show,
 396 };
 397
 398 static struct queue_sysfs_entry queue_write_same_max_entry = {
 399         .attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
 400         .show = queue_write_same_max_show,
 401 };
 402
 403 static struct queue_sysfs_entry queue_nonrot_entry = {
 404         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 405         .show = queue_show_nonrot,
 406         .store = queue_store_nonrot,
 407 };
 408
 409 static struct queue_sysfs_entry queue_nomerges_entry = {
 410         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 411         .show = queue_nomerges_show,
 412         .store = queue_nomerges_store,
 413 };
 414
 415 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 416         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 417         .show = queue_rq_affinity_show,
 418         .store = queue_rq_affinity_store,
 419 };
 420
 421 static struct queue_sysfs_entry queue_iostats_entry = {
 422         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 423         .show = queue_show_iostats,
 424         .store = queue_store_iostats,
 425 };
 426
 427 static struct queue_sysfs_entry queue_random_entry = {
 428         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
 429         .show = queue_show_random,
 430         .store = queue_store_random,
 431 };
 432
 433 static struct attribute *default_attrs[] = {
 434         &queue_requests_entry.attr,
 435         &queue_ra_entry.attr,
 436         &queue_max_hw_sectors_entry.attr,
 437         &queue_max_sectors_entry.attr,
 438         &queue_max_segments_entry.attr,
 439         &queue_max_integrity_segments_entry.attr,
 440         &queue_max_segment_size_entry.attr,
 441         &queue_iosched_entry.attr,
 442         &queue_hw_sector_size_entry.attr,
 443         &queue_logical_block_size_entry.attr,
 444         &queue_physical_block_size_entry.attr,
 445         &queue_io_min_entry.attr,
 446         &queue_io_opt_entry.attr,
 447         &queue_discard_granularity_entry.attr,
 448         &queue_discard_max_entry.attr,
 449         &queue_discard_zeroes_data_entry.attr,
 450         &queue_write_same_max_entry.attr,
 451         &queue_nonrot_entry.attr,
 452         &queue_nomerges_entry.attr,
 453         &queue_rq_affinity_entry.attr,
 454         &queue_iostats_entry.attr,
 455         &queue_random_entry.attr,
 456         NULL,
 457 };
 458
 459 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 460
 461 static ssize_t
 462 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 463 {
 464         struct queue_sysfs_entry *entry = to_queue(attr);
 465         struct request_queue *q =
 466                 container_of(kobj, struct request_queue, kobj);
 467         ssize_t res;
 468
 469         if (!entry->show)
 470                 return -EIO;
 471         mutex_lock(&q->sysfs_lock);
 472         if (blk_queue_dying(q)) {
 473                 mutex_unlock(&q->sysfs_lock);
 474                 return -ENOENT;
 475         }
 476         res = entry->show(q, page);
 477         mutex_unlock(&q->sysfs_lock);
 478         return res;
 479 }
 480
 481 static ssize_t
 482 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 483                     const char *page, size_t length)
 484 {
 485         struct queue_sysfs_entry *entry = to_queue(attr);
 486         struct request_queue *q;
 487         ssize_t res;
 488
 489         if (!entry->store)
 490                 return -EIO;
 491
 492         q = container_of(kobj, struct request_queue, kobj);
 493         mutex_lock(&q->sysfs_lock);
 494         if (blk_queue_dying(q)) {
 495                 mutex_unlock(&q->sysfs_lock);
 496                 return -ENOENT;
 497         }
 498         res = entry->store(q, page, length);
 499         mutex_unlock(&q->sysfs_lock);
 500         return res;
 501 }
 502
 503 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 504 {
 505         struct request_queue *q = container_of(rcu_head, struct request_queue,
 506                                                rcu_head);
 507         kmem_cache_free(blk_requestq_cachep, q);
 508 }
 509
 510 /**
 511  * blk_release_queue: - release a &struct request_queue when it is no longer needed
 512  * @kobj:    the kobj belonging to the request queue to be released
 513  *
 514  * Description:
 515  *     blk_release_queue is the pair to blk_init_queue() or
 516  *     blk_queue_make_request().  It should be called when a request queue is
 517  *     being released; typically when a block device is being de-registered.
 518  *     Currently, its primary task it to free all the &struct request
 519  *     structures that were allocated to the queue and the queue itself.
 520  *
 521  * Caveat:
 522  *     Hopefully the low level driver will have finished any
 523  *     outstanding requests first...
 524  **/
 525 static void blk_release_queue(struct kobject *kobj)
 526 {
 527         struct request_queue *q =
 528                 container_of(kobj, struct request_queue, kobj);
 529
 530         blk_sync_queue(q);
 531
 532         blkcg_exit_queue(q);
 533
 534         if (q->elevator) {
 535                 spin_lock_irq(q->queue_lock);
 536                 ioc_clear_queue(q);
 537                 spin_unlock_irq(q->queue_lock);
 538                 elevator_exit(q->elevator);
 539         }
 540
 541         blk_exit_rl(&q->root_rl);
 542
 543         if (q->queue_tags)
 544                 __blk_queue_free_tags(q);
 545
 546         percpu_counter_destroy(&q->mq_usage_counter);
 547
 548         if (q->mq_ops)
 549                 blk_mq_free_queue(q);
 550
 551         blk_trace_shutdown(q);
 552
 553         bdi_destroy(&q->backing_dev_info);
 554
 555         ida_simple_remove(&blk_queue_ida, q->id);
 556         call_rcu(&q->rcu_head, blk_free_queue_rcu);
 557 }
 558
 559 static const struct sysfs_ops queue_sysfs_ops = {
 560         .show   = queue_attr_show,
 561         .store  = queue_attr_store,
 562 };
 563
 564 struct kobj_type blk_queue_ktype = {
 565         .sysfs_ops      = &queue_sysfs_ops,
 566         .default_attrs  = default_attrs,
 567         .release        = blk_release_queue,
 568 };
 569
 570 int blk_register_queue(struct gendisk *disk)
 571 {
 572         int ret;
 573         struct device *dev = disk_to_dev(disk);
 574         struct request_queue *q = disk->queue;
 575
 576         if (WARN_ON(!q))
 577                 return -ENXIO;
 578
 579         /*
 580          * Initialization must be complete by now.  Finish the initial
 581          * bypass from queue allocation.
 582          */
 583         blk_queue_bypass_end(q);
 584         queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
 585
 586         ret = blk_trace_init_sysfs(dev);
 587         if (ret)
 588                 return ret;
 589
 590         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 591         if (ret < 0) {
 592                 blk_trace_remove_sysfs(dev);
 593                 return ret;
 594         }
 595
 596         kobject_uevent(&q->kobj, KOBJ_ADD);
 597
 598         if (q->mq_ops)
 599                 blk_mq_register_disk(disk);
 600
 601         if (!q->request_fn)
 602                 return 0;
 603
 604         ret = elv_register_queue(q);
 605         if (ret) {
 606                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 607                 kobject_del(&q->kobj);
 608                 blk_trace_remove_sysfs(dev);
 609                 kobject_put(&dev->kobj);
 610                 return ret;
 611         }
 612
 613         return 0;
 614 }
 615
 616 void blk_unregister_queue(struct gendisk *disk)
 617 {
 618         struct request_queue *q = disk->queue;
 619
 620         if (WARN_ON(!q))
 621                 return;
 622
 623         if (q->mq_ops)
 624                 blk_mq_unregister_disk(disk);
 625
 626         if (q->request_fn)
 627                 elv_unregister_queue(q);
 628
 629         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 630         kobject_del(&q->kobj);
 631         blk_trace_remove_sysfs(disk_to_dev(disk));
 632         kobject_put(&disk_to_dev(disk)->kobj);
 633 }