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