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