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 (neg)                                                        \
 233                 val = !val;                                             \
 234                                                                         \
 235         spin_lock_irq(q->queue_lock);                                   \
 236         if (val)                                                        \
 237                 queue_flag_set(QUEUE_FLAG_##flag, q);                   \
 238         else                                                            \
 239                 queue_flag_clear(QUEUE_FLAG_##flag, q);                 \
 240         spin_unlock_irq(q->queue_lock);                                 \
 241         return ret;                                                     \
 242 }
 243
 244 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 245 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 246 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 247 #undef QUEUE_SYSFS_BIT_FNS
 248
 249 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 250 {
 251         return queue_var_show((blk_queue_nomerges(q) << 1) |
 252                                blk_queue_noxmerges(q), page);
 253 }
 254
 255 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 256                                     size_t count)
 257 {
 258         unsigned long nm;
 259         ssize_t ret = queue_var_store(&nm, page, count);
 260
 261         if (ret < 0)
 262                 return ret;
 263
 264         spin_lock_irq(q->queue_lock);
 265         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 266         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 267         if (nm == 2)
 268                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 269         else if (nm)
 270                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 271         spin_unlock_irq(q->queue_lock);
 272
 273         return ret;
 274 }
 275
 276 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 277 {
 278         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 279         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 280
 281         return queue_var_show(set << force, page);
 282 }
 283
 284 static ssize_t
 285 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 286 {
 287         ssize_t ret = -EINVAL;
 288 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
 289         unsigned long val;
 290
 291         ret = queue_var_store(&val, page, count);
 292         if (ret < 0)
 293                 return ret;
 294
 295         spin_lock_irq(q->queue_lock);
 296         if (val == 2) {
 297                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 298                 queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 299         } else if (val == 1) {
 300                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 301                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 302         } else if (val == 0) {
 303                 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 304                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 305         }
 306         spin_unlock_irq(q->queue_lock);
 307 #endif
 308         return ret;
 309 }
 310
 311 static struct queue_sysfs_entry queue_requests_entry = {
 312         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 313         .show = queue_requests_show,
 314         .store = queue_requests_store,
 315 };
 316
 317 static struct queue_sysfs_entry queue_ra_entry = {
 318         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 319         .show = queue_ra_show,
 320         .store = queue_ra_store,
 321 };
 322
 323 static struct queue_sysfs_entry queue_max_sectors_entry = {
 324         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 325         .show = queue_max_sectors_show,
 326         .store = queue_max_sectors_store,
 327 };
 328
 329 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 330         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 331         .show = queue_max_hw_sectors_show,
 332 };
 333
 334 static struct queue_sysfs_entry queue_max_segments_entry = {
 335         .attr = {.name = "max_segments", .mode = S_IRUGO },
 336         .show = queue_max_segments_show,
 337 };
 338
 339 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
 340         .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
 341         .show = queue_max_integrity_segments_show,
 342 };
 343
 344 static struct queue_sysfs_entry queue_max_segment_size_entry = {
 345         .attr = {.name = "max_segment_size", .mode = S_IRUGO },
 346         .show = queue_max_segment_size_show,
 347 };
 348
 349 static struct queue_sysfs_entry queue_iosched_entry = {
 350         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 351         .show = elv_iosched_show,
 352         .store = elv_iosched_store,
 353 };
 354
 355 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 356         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 357         .show = queue_logical_block_size_show,
 358 };
 359
 360 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 361         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 362         .show = queue_logical_block_size_show,
 363 };
 364
 365 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 366         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 367         .show = queue_physical_block_size_show,
 368 };
 369
 370 static struct queue_sysfs_entry queue_io_min_entry = {
 371         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 372         .show = queue_io_min_show,
 373 };
 374
 375 static struct queue_sysfs_entry queue_io_opt_entry = {
 376         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 377         .show = queue_io_opt_show,
 378 };
 379
 380 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 381         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
 382         .show = queue_discard_granularity_show,
 383 };
 384
 385 static struct queue_sysfs_entry queue_discard_max_entry = {
 386         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
 387         .show = queue_discard_max_show,
 388 };
 389
 390 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 391         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
 392         .show = queue_discard_zeroes_data_show,
 393 };
 394
 395 static struct queue_sysfs_entry queue_write_same_max_entry = {
 396         .attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
 397         .show = queue_write_same_max_show,
 398 };
 399
 400 static struct queue_sysfs_entry queue_nonrot_entry = {
 401         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 402         .show = queue_show_nonrot,
 403         .store = queue_store_nonrot,
 404 };
 405
 406 static struct queue_sysfs_entry queue_nomerges_entry = {
 407         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 408         .show = queue_nomerges_show,
 409         .store = queue_nomerges_store,
 410 };
 411
 412 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 413         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 414         .show = queue_rq_affinity_show,
 415         .store = queue_rq_affinity_store,
 416 };
 417
 418 static struct queue_sysfs_entry queue_iostats_entry = {
 419         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 420         .show = queue_show_iostats,
 421         .store = queue_store_iostats,
 422 };
 423
 424 static struct queue_sysfs_entry queue_random_entry = {
 425         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
 426         .show = queue_show_random,
 427         .store = queue_store_random,
 428 };
 429
 430 static struct attribute *default_attrs[] = {
 431         &queue_requests_entry.attr,
 432         &queue_ra_entry.attr,
 433         &queue_max_hw_sectors_entry.attr,
 434         &queue_max_sectors_entry.attr,
 435         &queue_max_segments_entry.attr,
 436         &queue_max_integrity_segments_entry.attr,
 437         &queue_max_segment_size_entry.attr,
 438         &queue_iosched_entry.attr,
 439         &queue_hw_sector_size_entry.attr,
 440         &queue_logical_block_size_entry.attr,
 441         &queue_physical_block_size_entry.attr,
 442         &queue_io_min_entry.attr,
 443         &queue_io_opt_entry.attr,
 444         &queue_discard_granularity_entry.attr,
 445         &queue_discard_max_entry.attr,
 446         &queue_discard_zeroes_data_entry.attr,
 447         &queue_write_same_max_entry.attr,
 448         &queue_nonrot_entry.attr,
 449         &queue_nomerges_entry.attr,
 450         &queue_rq_affinity_entry.attr,
 451         &queue_iostats_entry.attr,
 452         &queue_random_entry.attr,
 453         NULL,
 454 };
 455
 456 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 457
 458 static ssize_t
 459 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 460 {
 461         struct queue_sysfs_entry *entry = to_queue(attr);
 462         struct request_queue *q =
 463                 container_of(kobj, struct request_queue, kobj);
 464         ssize_t res;
 465
 466         if (!entry->show)
 467                 return -EIO;
 468         mutex_lock(&q->sysfs_lock);
 469         if (blk_queue_dying(q)) {
 470                 mutex_unlock(&q->sysfs_lock);
 471                 return -ENOENT;
 472         }
 473         res = entry->show(q, page);
 474         mutex_unlock(&q->sysfs_lock);
 475         return res;
 476 }
 477
 478 static ssize_t
 479 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 480                     const char *page, size_t length)
 481 {
 482         struct queue_sysfs_entry *entry = to_queue(attr);
 483         struct request_queue *q;
 484         ssize_t res;
 485
 486         if (!entry->store)
 487                 return -EIO;
 488
 489         q = container_of(kobj, struct request_queue, kobj);
 490         mutex_lock(&q->sysfs_lock);
 491         if (blk_queue_dying(q)) {
 492                 mutex_unlock(&q->sysfs_lock);
 493                 return -ENOENT;
 494         }
 495         res = entry->store(q, page, length);
 496         mutex_unlock(&q->sysfs_lock);
 497         return res;
 498 }
 499
 500 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 501 {
 502         struct request_queue *q = container_of(rcu_head, struct request_queue,
 503                                                rcu_head);
 504         kmem_cache_free(blk_requestq_cachep, q);
 505 }
 506
 507 /**
 508  * blk_release_queue: - release a &struct request_queue when it is no longer needed
 509  * @kobj:    the kobj belonging to the request queue to be released
 510  *
 511  * Description:
 512  *     blk_release_queue is the pair to blk_init_queue() or
 513  *     blk_queue_make_request().  It should be called when a request queue is
 514  *     being released; typically when a block device is being de-registered.
 515  *     Currently, its primary task it to free all the &struct request
 516  *     structures that were allocated to the queue and the queue itself.
 517  *
 518  * Caveat:
 519  *     Hopefully the low level driver will have finished any
 520  *     outstanding requests first...
 521  **/
 522 static void blk_release_queue(struct kobject *kobj)
 523 {
 524         struct request_queue *q =
 525                 container_of(kobj, struct request_queue, kobj);
 526
 527         blk_sync_queue(q);
 528
 529         blkcg_exit_queue(q);
 530
 531         if (q->elevator) {
 532                 spin_lock_irq(q->queue_lock);
 533                 ioc_clear_queue(q);
 534                 spin_unlock_irq(q->queue_lock);
 535                 elevator_exit(q->elevator);
 536         }
 537
 538         blk_exit_rl(&q->root_rl);
 539
 540         if (q->queue_tags)
 541                 __blk_queue_free_tags(q);
 542
 543         blk_trace_shutdown(q);
 544
 545         bdi_destroy(&q->backing_dev_info);
 546
 547         ida_simple_remove(&blk_queue_ida, q->id);
 548         call_rcu(&q->rcu_head, blk_free_queue_rcu);
 549 }
 550
 551 static const struct sysfs_ops queue_sysfs_ops = {
 552         .show   = queue_attr_show,
 553         .store  = queue_attr_store,
 554 };
 555
 556 struct kobj_type blk_queue_ktype = {
 557         .sysfs_ops      = &queue_sysfs_ops,
 558         .default_attrs  = default_attrs,
 559         .release        = blk_release_queue,
 560 };
 561
 562 int blk_register_queue(struct gendisk *disk)
 563 {
 564         int ret;
 565         struct device *dev = disk_to_dev(disk);
 566         struct request_queue *q = disk->queue;
 567
 568         if (WARN_ON(!q))
 569                 return -ENXIO;
 570
 571         /*
 572          * Initialization must be complete by now.  Finish the initial
 573          * bypass from queue allocation.
 574          */
 575         blk_queue_bypass_end(q);
 576
 577         ret = blk_trace_init_sysfs(dev);
 578         if (ret)
 579                 return ret;
 580
 581         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 582         if (ret < 0) {
 583                 blk_trace_remove_sysfs(dev);
 584                 return ret;
 585         }
 586
 587         kobject_uevent(&q->kobj, KOBJ_ADD);
 588
 589         if (!q->request_fn)
 590                 return 0;
 591
 592         ret = elv_register_queue(q);
 593         if (ret) {
 594                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 595                 kobject_del(&q->kobj);
 596                 blk_trace_remove_sysfs(dev);
 597                 kobject_put(&dev->kobj);
 598                 return ret;
 599         }
 600
 601         return 0;
 602 }
 603
 604 void blk_unregister_queue(struct gendisk *disk)
 605 {
 606         struct request_queue *q = disk->queue;
 607
 608         if (WARN_ON(!q))
 609                 return;
 610
 611         if (q->request_fn)
 612                 elv_unregister_queue(q);
 613
 614         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 615         kobject_del(&q->kobj);
 616         blk_trace_remove_sysfs(disk_to_dev(disk));
 617         kobject_put(&disk_to_dev(disk)->kobj);
 618 }