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 #include "blk-mq.h"
  15
  16 struct queue_sysfs_entry {
  17         struct attribute attr;
  18         ssize_t (*show)(struct request_queue *, char *);
  19         ssize_t (*store)(struct request_queue *, const char *, size_t);
  20 };
  21
  22 static ssize_t
  23 queue_var_show(unsigned long var, char *page)
  24 {
  25         return sprintf(page, "%lu\n", var);
  26 }
  27
  28 static ssize_t
  29 queue_var_store(unsigned long *var, const char *page, size_t count)
  30 {
  31         int err;
  32         unsigned long v;
  33
  34         err = kstrtoul(page, 10, &v);
  35         if (err || v > UINT_MAX)
  36                 return -EINVAL;
  37
  38         *var = v;
  39
  40         return count;
  41 }
  42
  43 static ssize_t queue_requests_show(struct request_queue *q, char *page)
  44 {
  45         return queue_var_show(q->nr_requests, (page));
  46 }
  47
  48 static ssize_t
  49 queue_requests_store(struct request_queue *q, const char *page, size_t count)
  50 {
  51         struct request_list *rl;
  52         unsigned long nr;
  53         int ret;
  54
  55         if (!q->request_fn)
  56                 return -EINVAL;
  57
  58         ret = queue_var_store(&nr, page, count);
  59         if (ret < 0)
  60                 return ret;
  61
  62         if (nr < BLKDEV_MIN_RQ)
  63                 nr = BLKDEV_MIN_RQ;
  64
  65         spin_lock_irq(q->queue_lock);
  66         q->nr_requests = nr;
  67         blk_queue_congestion_threshold(q);
  68
  69         /* congestion isn't cgroup aware and follows root blkcg for now */
  70         rl = &q->root_rl;
  71
  72         if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
  73                 blk_set_queue_congested(q, BLK_RW_SYNC);
  74         else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
  75                 blk_clear_queue_congested(q, BLK_RW_SYNC);
  76
  77         if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
  78                 blk_set_queue_congested(q, BLK_RW_ASYNC);
  79         else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
  80                 blk_clear_queue_congested(q, BLK_RW_ASYNC);
  81
  82         blk_queue_for_each_rl(rl, q) {
  83                 if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
  84                         blk_set_rl_full(rl, BLK_RW_SYNC);
  85                 } else {
  86                         blk_clear_rl_full(rl, BLK_RW_SYNC);
  87                         wake_up(&rl->wait[BLK_RW_SYNC]);
  88                 }
  89
  90                 if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
  91                         blk_set_rl_full(rl, BLK_RW_ASYNC);
  92                 } else {
  93                         blk_clear_rl_full(rl, BLK_RW_ASYNC);
  94                         wake_up(&rl->wait[BLK_RW_ASYNC]);
  95                 }
  96         }
  97
  98         spin_unlock_irq(q->queue_lock);
  99         return ret;
 100 }
 101
 102 static ssize_t queue_ra_show(struct request_queue *q, char *page)
 103 {
 104         unsigned long ra_kb = q->backing_dev_info.ra_pages <<
 105                                         (PAGE_CACHE_SHIFT - 10);
 106
 107         return queue_var_show(ra_kb, (page));
 108 }
 109
 110 static ssize_t
 111 queue_ra_store(struct request_queue *q, const char *page, size_t count)
 112 {
 113         unsigned long ra_kb;
 114         ssize_t ret = queue_var_store(&ra_kb, page, count);
 115
 116         if (ret < 0)
 117                 return ret;
 118
 119         q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
 120
 121         return ret;
 122 }
 123
 124 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
 125 {
 126         int max_sectors_kb = queue_max_sectors(q) >> 1;
 127
 128         return queue_var_show(max_sectors_kb, (page));
 129 }
 130
 131 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
 132 {
 133         return queue_var_show(queue_max_segments(q), (page));
 134 }
 135
 136 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
 137 {
 138         return queue_var_show(q->limits.max_integrity_segments, (page));
 139 }
 140
 141 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 142 {
 143         if (blk_queue_cluster(q))
 144                 return queue_var_show(queue_max_segment_size(q), (page));
 145
 146         return queue_var_show(PAGE_CACHE_SIZE, (page));
 147 }
 148
 149 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 150 {
 151         return queue_var_show(queue_logical_block_size(q), page);
 152 }
 153
 154 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 155 {
 156         return queue_var_show(queue_physical_block_size(q), page);
 157 }
 158
 159 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 160 {
 161         return queue_var_show(queue_io_min(q), page);
 162 }
 163
 164 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 165 {
 166         return queue_var_show(queue_io_opt(q), page);
 167 }
 168
 169 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 170 {
 171         return queue_var_show(q->limits.discard_granularity, page);
 172 }
 173
 174 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 175 {
 176         return sprintf(page, "%llu\n",
 177                        (unsigned long long)q->limits.max_discard_sectors << 9);
 178 }
 179
 180 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 181 {
 182         return queue_var_show(queue_discard_zeroes_data(q), page);
 183 }
 184
 185 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
 186 {
 187         return sprintf(page, "%llu\n",
 188                 (unsigned long long)q->limits.max_write_same_sectors << 9);
 189 }
 190
 191
 192 static ssize_t
 193 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 194 {
 195         unsigned long max_sectors_kb,
 196                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 197                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
 198         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 199
 200         if (ret < 0)
 201                 return ret;
 202
 203         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 204                 return -EINVAL;
 205
 206         spin_lock_irq(q->queue_lock);
 207         q->limits.max_sectors = max_sectors_kb << 1;
 208         spin_unlock_irq(q->queue_lock);
 209
 210         return ret;
 211 }
 212
 213 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 214 {
 215         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 216
 217         return queue_var_show(max_hw_sectors_kb, (page));
 218 }
 219
 220 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 221 static ssize_t                                                          \
 222 queue_show_##name(struct request_queue *q, char *page)                  \
 223 {                                                                       \
 224         int bit;                                                        \
 225         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 226         return queue_var_show(neg ? !bit : bit, page);                  \
 227 }                                                                       \
 228 static ssize_t                                                          \
 229 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
 230 {                                                                       \
 231         unsigned long val;                                              \
 232         ssize_t ret;                                                    \
 233         ret = queue_var_store(&val, page, count);                       \
 234         if (ret < 0)                                                    \
 235                  return ret;                                            \
 236         if (neg)                                                        \
 237                 val = !val;                                             \
 238                                                                         \
 239         spin_lock_irq(q->queue_lock);                                   \
 240         if (val)                                                        \
 241                 queue_flag_set(QUEUE_FLAG_##flag, q);                   \
 242         else                                                            \
 243                 queue_flag_clear(QUEUE_FLAG_##flag, q);                 \
 244         spin_unlock_irq(q->queue_lock);                                 \
 245         return ret;                                                     \
 246 }
 247
 248 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 249 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 250 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 251 #undef QUEUE_SYSFS_BIT_FNS
 252
 253 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 254 {
 255         return queue_var_show((blk_queue_nomerges(q) << 1) |
 256                                blk_queue_noxmerges(q), page);
 257 }
 258
 259 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 260                                     size_t count)
 261 {
 262         unsigned long nm;
 263         ssize_t ret = queue_var_store(&nm, page, count);
 264
 265         if (ret < 0)
 266                 return ret;
 267
 268         spin_lock_irq(q->queue_lock);
 269         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 270         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 271         if (nm == 2)
 272                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 273         else if (nm)
 274                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 275         spin_unlock_irq(q->queue_lock);
 276
 277         return ret;
 278 }
 279
 280 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 281 {
 282         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 283         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 284
 285         return queue_var_show(set << force, page);
 286 }
 287
 288 static ssize_t
 289 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 290 {
 291         ssize_t ret = -EINVAL;
 292 #ifdef CONFIG_SMP
 293         unsigned long val;
 294
 295         ret = queue_var_store(&val, page, count);
 296         if (ret < 0)
 297                 return ret;
 298
 299         spin_lock_irq(q->queue_lock);
 300         if (val == 2) {
 301                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 302                 queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 303         } else if (val == 1) {
 304                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 305                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 306         } else if (val == 0) {
 307                 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 308                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 309         }
 310         spin_unlock_irq(q->queue_lock);
 311 #endif
 312         return ret;
 313 }
 314
 315 static struct queue_sysfs_entry queue_requests_entry = {
 316         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 317         .show = queue_requests_show,
 318         .store = queue_requests_store,
 319 };
 320
 321 static struct queue_sysfs_entry queue_ra_entry = {
 322         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 323         .show = queue_ra_show,
 324         .store = queue_ra_store,
 325 };
 326
 327 static struct queue_sysfs_entry queue_max_sectors_entry = {
 328         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 329         .show = queue_max_sectors_show,
 330         .store = queue_max_sectors_store,
 331 };
 332
 333 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 334         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 335         .show = queue_max_hw_sectors_show,
 336 };
 337
 338 static struct queue_sysfs_entry queue_max_segments_entry = {
 339         .attr = {.name = "max_segments", .mode = S_IRUGO },
 340         .show = queue_max_segments_show,
 341 };
 342
 343 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
 344         .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
 345         .show = queue_max_integrity_segments_show,
 346 };
 347
 348 static struct queue_sysfs_entry queue_max_segment_size_entry = {
 349         .attr = {.name = "max_segment_size", .mode = S_IRUGO },
 350         .show = queue_max_segment_size_show,
 351 };
 352
 353 static struct queue_sysfs_entry queue_iosched_entry = {
 354         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 355         .show = elv_iosched_show,
 356         .store = elv_iosched_store,
 357 };
 358
 359 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 360         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 361         .show = queue_logical_block_size_show,
 362 };
 363
 364 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 365         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 366         .show = queue_logical_block_size_show,
 367 };
 368
 369 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 370         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 371         .show = queue_physical_block_size_show,
 372 };
 373
 374 static struct queue_sysfs_entry queue_io_min_entry = {
 375         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 376         .show = queue_io_min_show,
 377 };
 378
 379 static struct queue_sysfs_entry queue_io_opt_entry = {
 380         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 381         .show = queue_io_opt_show,
 382 };
 383
 384 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 385         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
 386         .show = queue_discard_granularity_show,
 387 };
 388
 389 static struct queue_sysfs_entry queue_discard_max_entry = {
 390         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
 391         .show = queue_discard_max_show,
 392 };
 393
 394 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 395         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
 396         .show = queue_discard_zeroes_data_show,
 397 };
 398
 399 static struct queue_sysfs_entry queue_write_same_max_entry = {
 400         .attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
 401         .show = queue_write_same_max_show,
 402 };
 403
 404 static struct queue_sysfs_entry queue_nonrot_entry = {
 405         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 406         .show = queue_show_nonrot,
 407         .store = queue_store_nonrot,
 408 };
 409
 410 static struct queue_sysfs_entry queue_nomerges_entry = {
 411         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 412         .show = queue_nomerges_show,
 413         .store = queue_nomerges_store,
 414 };
 415
 416 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 417         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 418         .show = queue_rq_affinity_show,
 419         .store = queue_rq_affinity_store,
 420 };
 421
 422 static struct queue_sysfs_entry queue_iostats_entry = {
 423         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 424         .show = queue_show_iostats,
 425         .store = queue_store_iostats,
 426 };
 427
 428 static struct queue_sysfs_entry queue_random_entry = {
 429         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
 430         .show = queue_show_random,
 431         .store = queue_store_random,
 432 };
 433
 434 static struct attribute *default_attrs[] = {
 435         &queue_requests_entry.attr,
 436         &queue_ra_entry.attr,
 437         &queue_max_hw_sectors_entry.attr,
 438         &queue_max_sectors_entry.attr,
 439         &queue_max_segments_entry.attr,
 440         &queue_max_integrity_segments_entry.attr,
 441         &queue_max_segment_size_entry.attr,
 442         &queue_iosched_entry.attr,
 443         &queue_hw_sector_size_entry.attr,
 444         &queue_logical_block_size_entry.attr,
 445         &queue_physical_block_size_entry.attr,
 446         &queue_io_min_entry.attr,
 447         &queue_io_opt_entry.attr,
 448         &queue_discard_granularity_entry.attr,
 449         &queue_discard_max_entry.attr,
 450         &queue_discard_zeroes_data_entry.attr,
 451         &queue_write_same_max_entry.attr,
 452         &queue_nonrot_entry.attr,
 453         &queue_nomerges_entry.attr,
 454         &queue_rq_affinity_entry.attr,
 455         &queue_iostats_entry.attr,
 456         &queue_random_entry.attr,
 457         NULL,
 458 };
 459
 460 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 461
 462 static ssize_t
 463 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 464 {
 465         struct queue_sysfs_entry *entry = to_queue(attr);
 466         struct request_queue *q =
 467                 container_of(kobj, struct request_queue, kobj);
 468         ssize_t res;
 469
 470         if (!entry->show)
 471                 return -EIO;
 472         mutex_lock(&q->sysfs_lock);
 473         if (blk_queue_dying(q)) {
 474                 mutex_unlock(&q->sysfs_lock);
 475                 return -ENOENT;
 476         }
 477         res = entry->show(q, page);
 478         mutex_unlock(&q->sysfs_lock);
 479         return res;
 480 }
 481
 482 static ssize_t
 483 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 484                     const char *page, size_t length)
 485 {
 486         struct queue_sysfs_entry *entry = to_queue(attr);
 487         struct request_queue *q;
 488         ssize_t res;
 489
 490         if (!entry->store)
 491                 return -EIO;
 492
 493         q = container_of(kobj, struct request_queue, kobj);
 494         mutex_lock(&q->sysfs_lock);
 495         if (blk_queue_dying(q)) {
 496                 mutex_unlock(&q->sysfs_lock);
 497                 return -ENOENT;
 498         }
 499         res = entry->store(q, page, length);
 500         mutex_unlock(&q->sysfs_lock);
 501         return res;
 502 }
 503
 504 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 505 {
 506         struct request_queue *q = container_of(rcu_head, struct request_queue,
 507                                                rcu_head);
 508         kmem_cache_free(blk_requestq_cachep, q);
 509 }
 510
 511 /**
 512  * blk_release_queue: - release a &struct request_queue when it is no longer needed
 513  * @kobj:    the kobj belonging to the request queue to be released
 514  *
 515  * Description:
 516  *     blk_release_queue is the pair to blk_init_queue() or
 517  *     blk_queue_make_request().  It should be called when a request queue is
 518  *     being released; typically when a block device is being de-registered.
 519  *     Currently, its primary task it to free all the &struct request
 520  *     structures that were allocated to the queue and the queue itself.
 521  *
 522  * Caveat:
 523  *     Hopefully the low level driver will have finished any
 524  *     outstanding requests first...
 525  **/
 526 static void blk_release_queue(struct kobject *kobj)
 527 {
 528         struct request_queue *q =
 529                 container_of(kobj, struct request_queue, kobj);
 530
 531         blk_sync_queue(q);
 532
 533         blkcg_exit_queue(q);
 534
 535         if (q->elevator) {
 536                 spin_lock_irq(q->queue_lock);
 537                 ioc_clear_queue(q);
 538                 spin_unlock_irq(q->queue_lock);
 539                 elevator_exit(q->elevator);
 540         }
 541
 542         blk_exit_rl(&q->root_rl);
 543
 544         if (q->queue_tags)
 545                 __blk_queue_free_tags(q);
 546
 547         percpu_counter_destroy(&q->mq_usage_counter);
 548
 549         if (q->mq_ops)
 550                 blk_mq_free_queue(q);
 551
 552         kfree(q->flush_rq);
 553
 554         blk_trace_shutdown(q);
 555
 556         bdi_destroy(&q->backing_dev_info);
 557
 558         ida_simple_remove(&blk_queue_ida, q->id);
 559         call_rcu(&q->rcu_head, blk_free_queue_rcu);
 560 }
 561
 562 static const struct sysfs_ops queue_sysfs_ops = {
 563         .show   = queue_attr_show,
 564         .store  = queue_attr_store,
 565 };
 566
 567 struct kobj_type blk_queue_ktype = {
 568         .sysfs_ops      = &queue_sysfs_ops,
 569         .default_attrs  = default_attrs,
 570         .release        = blk_release_queue,
 571 };
 572
 573 int blk_register_queue(struct gendisk *disk)
 574 {
 575         int ret;
 576         struct device *dev = disk_to_dev(disk);
 577         struct request_queue *q = disk->queue;
 578
 579         if (WARN_ON(!q))
 580                 return -ENXIO;
 581
 582         /*
 583          * Initialization must be complete by now.  Finish the initial
 584          * bypass from queue allocation.
 585          */
 586         blk_queue_bypass_end(q);
 587         queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
 588
 589         ret = blk_trace_init_sysfs(dev);
 590         if (ret)
 591                 return ret;
 592
 593         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 594         if (ret < 0) {
 595                 blk_trace_remove_sysfs(dev);
 596                 return ret;
 597         }
 598
 599         kobject_uevent(&q->kobj, KOBJ_ADD);
 600
 601         if (q->mq_ops)
 602                 blk_mq_register_disk(disk);
 603
 604         if (!q->request_fn)
 605                 return 0;
 606
 607         ret = elv_register_queue(q);
 608         if (ret) {
 609                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 610                 kobject_del(&q->kobj);
 611                 blk_trace_remove_sysfs(dev);
 612                 kobject_put(&dev->kobj);
 613                 return ret;
 614         }
 615
 616         return 0;
 617 }
 618
 619 void blk_unregister_queue(struct gendisk *disk)
 620 {
 621         struct request_queue *q = disk->queue;
 622
 623         if (WARN_ON(!q))
 624                 return;
 625
 626         if (q->mq_ops)
 627                 blk_mq_unregister_disk(disk);
 628
 629         if (q->request_fn)
 630                 elv_unregister_queue(q);
 631
 632         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 633         kobject_del(&q->kobj);
 634         blk_trace_remove_sysfs(disk_to_dev(disk));
 635         kobject_put(&disk_to_dev(disk)->kobj);
 636 }