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