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