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
 184 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 185 {
 186         unsigned long max_sectors_kb,
 187                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 188                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
 189         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 190
 191         if (ret < 0)
 192                 return ret;
 193
 194         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 195                 return -EINVAL;
 196
 197         spin_lock_irq(q->queue_lock);
 198         q->limits.max_sectors = max_sectors_kb << 1;
 199         spin_unlock_irq(q->queue_lock);
 200
 201         return ret;
 202 }
 203
 204 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 205 {
 206         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 207
 208         return queue_var_show(max_hw_sectors_kb, (page));
 209 }
 210
 211 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 212 static ssize_t                                                          \
 213 queue_show_##name(struct request_queue *q, char *page)                  \
 214 {                                                                       \
 215         int bit;                                                        \
 216         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 217         return queue_var_show(neg ? !bit : bit, page);                  \
 218 }                                                                       \
 219 static ssize_t                                                          \
 220 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
 221 {                                                                       \
 222         unsigned long val;                                              \
 223         ssize_t ret;                                                    \
 224         ret = queue_var_store(&val, page, count);                       \
 225         if (neg)                                                        \
 226                 val = !val;                                             \
 227                                                                         \
 228         spin_lock_irq(q->queue_lock);                                   \
 229         if (val)                                                        \
 230                 queue_flag_set(QUEUE_FLAG_##flag, q);                   \
 231         else                                                            \
 232                 queue_flag_clear(QUEUE_FLAG_##flag, q);                 \
 233         spin_unlock_irq(q->queue_lock);                                 \
 234         return ret;                                                     \
 235 }
 236
 237 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 238 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 239 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 240 #undef QUEUE_SYSFS_BIT_FNS
 241
 242 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 243 {
 244         return queue_var_show((blk_queue_nomerges(q) << 1) |
 245                                blk_queue_noxmerges(q), page);
 246 }
 247
 248 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 249                                     size_t count)
 250 {
 251         unsigned long nm;
 252         ssize_t ret = queue_var_store(&nm, page, count);
 253
 254         if (ret < 0)
 255                 return ret;
 256
 257         spin_lock_irq(q->queue_lock);
 258         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 259         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 260         if (nm == 2)
 261                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 262         else if (nm)
 263                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 264         spin_unlock_irq(q->queue_lock);
 265
 266         return ret;
 267 }
 268
 269 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 270 {
 271         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 272         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 273
 274         return queue_var_show(set << force, page);
 275 }
 276
 277 static ssize_t
 278 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 279 {
 280         ssize_t ret = -EINVAL;
 281 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
 282         unsigned long val;
 283
 284         ret = queue_var_store(&val, page, count);
 285         if (ret < 0)
 286                 return ret;
 287
 288         spin_lock_irq(q->queue_lock);
 289         if (val == 2) {
 290                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 291                 queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 292         } else if (val == 1) {
 293                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 294                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 295         } else if (val == 0) {
 296                 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 297                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 298         }
 299         spin_unlock_irq(q->queue_lock);
 300 #endif
 301         return ret;
 302 }
 303
 304 static struct queue_sysfs_entry queue_requests_entry = {
 305         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 306         .show = queue_requests_show,
 307         .store = queue_requests_store,
 308 };
 309
 310 static struct queue_sysfs_entry queue_ra_entry = {
 311         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 312         .show = queue_ra_show,
 313         .store = queue_ra_store,
 314 };
 315
 316 static struct queue_sysfs_entry queue_max_sectors_entry = {
 317         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 318         .show = queue_max_sectors_show,
 319         .store = queue_max_sectors_store,
 320 };
 321
 322 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 323         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 324         .show = queue_max_hw_sectors_show,
 325 };
 326
 327 static struct queue_sysfs_entry queue_max_segments_entry = {
 328         .attr = {.name = "max_segments", .mode = S_IRUGO },
 329         .show = queue_max_segments_show,
 330 };
 331
 332 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
 333         .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
 334         .show = queue_max_integrity_segments_show,
 335 };
 336
 337 static struct queue_sysfs_entry queue_max_segment_size_entry = {
 338         .attr = {.name = "max_segment_size", .mode = S_IRUGO },
 339         .show = queue_max_segment_size_show,
 340 };
 341
 342 static struct queue_sysfs_entry queue_iosched_entry = {
 343         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 344         .show = elv_iosched_show,
 345         .store = elv_iosched_store,
 346 };
 347
 348 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 349         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 350         .show = queue_logical_block_size_show,
 351 };
 352
 353 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 354         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 355         .show = queue_logical_block_size_show,
 356 };
 357
 358 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 359         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 360         .show = queue_physical_block_size_show,
 361 };
 362
 363 static struct queue_sysfs_entry queue_io_min_entry = {
 364         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 365         .show = queue_io_min_show,
 366 };
 367
 368 static struct queue_sysfs_entry queue_io_opt_entry = {
 369         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 370         .show = queue_io_opt_show,
 371 };
 372
 373 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 374         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
 375         .show = queue_discard_granularity_show,
 376 };
 377
 378 static struct queue_sysfs_entry queue_discard_max_entry = {
 379         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
 380         .show = queue_discard_max_show,
 381 };
 382
 383 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 384         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
 385         .show = queue_discard_zeroes_data_show,
 386 };
 387
 388 static struct queue_sysfs_entry queue_nonrot_entry = {
 389         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 390         .show = queue_show_nonrot,
 391         .store = queue_store_nonrot,
 392 };
 393
 394 static struct queue_sysfs_entry queue_nomerges_entry = {
 395         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 396         .show = queue_nomerges_show,
 397         .store = queue_nomerges_store,
 398 };
 399
 400 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 401         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 402         .show = queue_rq_affinity_show,
 403         .store = queue_rq_affinity_store,
 404 };
 405
 406 static struct queue_sysfs_entry queue_iostats_entry = {
 407         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 408         .show = queue_show_iostats,
 409         .store = queue_store_iostats,
 410 };
 411
 412 static struct queue_sysfs_entry queue_random_entry = {
 413         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
 414         .show = queue_show_random,
 415         .store = queue_store_random,
 416 };
 417
 418 static struct attribute *default_attrs[] = {
 419         &queue_requests_entry.attr,
 420         &queue_ra_entry.attr,
 421         &queue_max_hw_sectors_entry.attr,
 422         &queue_max_sectors_entry.attr,
 423         &queue_max_segments_entry.attr,
 424         &queue_max_integrity_segments_entry.attr,
 425         &queue_max_segment_size_entry.attr,
 426         &queue_iosched_entry.attr,
 427         &queue_hw_sector_size_entry.attr,
 428         &queue_logical_block_size_entry.attr,
 429         &queue_physical_block_size_entry.attr,
 430         &queue_io_min_entry.attr,
 431         &queue_io_opt_entry.attr,
 432         &queue_discard_granularity_entry.attr,
 433         &queue_discard_max_entry.attr,
 434         &queue_discard_zeroes_data_entry.attr,
 435         &queue_nonrot_entry.attr,
 436         &queue_nomerges_entry.attr,
 437         &queue_rq_affinity_entry.attr,
 438         &queue_iostats_entry.attr,
 439         &queue_random_entry.attr,
 440         NULL,
 441 };
 442
 443 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 444
 445 static ssize_t
 446 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 447 {
 448         struct queue_sysfs_entry *entry = to_queue(attr);
 449         struct request_queue *q =
 450                 container_of(kobj, struct request_queue, kobj);
 451         ssize_t res;
 452
 453         if (!entry->show)
 454                 return -EIO;
 455         mutex_lock(&q->sysfs_lock);
 456         if (blk_queue_dead(q)) {
 457                 mutex_unlock(&q->sysfs_lock);
 458                 return -ENOENT;
 459         }
 460         res = entry->show(q, page);
 461         mutex_unlock(&q->sysfs_lock);
 462         return res;
 463 }
 464
 465 static ssize_t
 466 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 467                     const char *page, size_t length)
 468 {
 469         struct queue_sysfs_entry *entry = to_queue(attr);
 470         struct request_queue *q;
 471         ssize_t res;
 472
 473         if (!entry->store)
 474                 return -EIO;
 475
 476         q = container_of(kobj, struct request_queue, kobj);
 477         mutex_lock(&q->sysfs_lock);
 478         if (blk_queue_dead(q)) {
 479                 mutex_unlock(&q->sysfs_lock);
 480                 return -ENOENT;
 481         }
 482         res = entry->store(q, page, length);
 483         mutex_unlock(&q->sysfs_lock);
 484         return res;
 485 }
 486
 487 /**
 488  * blk_release_queue: - release a &struct request_queue when it is no longer needed
 489  * @kobj:    the kobj belonging to the request queue to be released
 490  *
 491  * Description:
 492  *     blk_release_queue is the pair to blk_init_queue() or
 493  *     blk_queue_make_request().  It should be called when a request queue is
 494  *     being released; typically when a block device is being de-registered.
 495  *     Currently, its primary task it to free all the &struct request
 496  *     structures that were allocated to the queue and the queue itself.
 497  *
 498  * Caveat:
 499  *     Hopefully the low level driver will have finished any
 500  *     outstanding requests first...
 501  **/
 502 static void blk_release_queue(struct kobject *kobj)
 503 {
 504         struct request_queue *q =
 505                 container_of(kobj, struct request_queue, kobj);
 506
 507         blk_sync_queue(q);
 508
 509         blkcg_exit_queue(q);
 510
 511         if (q->elevator) {
 512                 spin_lock_irq(q->queue_lock);
 513                 ioc_clear_queue(q);
 514                 spin_unlock_irq(q->queue_lock);
 515                 elevator_exit(q->elevator);
 516         }
 517
 518         blk_exit_rl(&q->root_rl);
 519
 520         if (q->queue_tags)
 521                 __blk_queue_free_tags(q);
 522
 523         blk_trace_shutdown(q);
 524
 525         bdi_destroy(&q->backing_dev_info);
 526
 527         ida_simple_remove(&blk_queue_ida, q->id);
 528         kmem_cache_free(blk_requestq_cachep, q);
 529 }
 530
 531 static const struct sysfs_ops queue_sysfs_ops = {
 532         .show   = queue_attr_show,
 533         .store  = queue_attr_store,
 534 };
 535
 536 struct kobj_type blk_queue_ktype = {
 537         .sysfs_ops      = &queue_sysfs_ops,
 538         .default_attrs  = default_attrs,
 539         .release        = blk_release_queue,
 540 };
 541
 542 int blk_register_queue(struct gendisk *disk)
 543 {
 544         int ret;
 545         struct device *dev = disk_to_dev(disk);
 546         struct request_queue *q = disk->queue;
 547
 548         if (WARN_ON(!q))
 549                 return -ENXIO;
 550
 551         ret = blk_trace_init_sysfs(dev);
 552         if (ret)
 553                 return ret;
 554
 555         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 556         if (ret < 0) {
 557                 blk_trace_remove_sysfs(dev);
 558                 return ret;
 559         }
 560
 561         kobject_uevent(&q->kobj, KOBJ_ADD);
 562
 563         if (!q->request_fn)
 564                 return 0;
 565
 566         ret = elv_register_queue(q);
 567         if (ret) {
 568                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 569                 kobject_del(&q->kobj);
 570                 blk_trace_remove_sysfs(dev);
 571                 kobject_put(&dev->kobj);
 572                 return ret;
 573         }
 574
 575         return 0;
 576 }
 577
 578 void blk_unregister_queue(struct gendisk *disk)
 579 {
 580         struct request_queue *q = disk->queue;
 581
 582         if (WARN_ON(!q))
 583                 return;
 584
 585         if (q->request_fn)
 586                 elv_unregister_queue(q);
 587
 588         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 589         kobject_del(&q->kobj);
 590         blk_trace_remove_sysfs(disk_to_dev(disk));
 591         kobject_put(&disk_to_dev(disk)->kobj);
 592 }