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   1 /*
   2  * Functions related to sysfs handling
   3  */
   4 #include <linux/kernel.h>
   5 #include <linux/module.h>
   6 #include <linux/bio.h>
   7 #include <linux/blkdev.h>
   8 #include <linux/blktrace_api.h>
   9
  10 #include "blk.h"
  11
  12 struct queue_sysfs_entry {
  13         struct attribute attr;
  14         ssize_t (*show)(struct request_queue *, char *);
  15         ssize_t (*store)(struct request_queue *, const char *, size_t);
  16 };
  17
  18 static ssize_t
  19 queue_var_show(unsigned long var, char *page)
  20 {
  21         return sprintf(page, "%lu\n", var);
  22 }
  23
  24 static ssize_t
  25 queue_var_store(unsigned long *var, const char *page, size_t count)
  26 {
  27         char *p = (char *) page;
  28
  29         *var = simple_strtoul(p, &p, 10);
  30         return count;
  31 }
  32
  33 static ssize_t queue_requests_show(struct request_queue *q, char *page)
  34 {
  35         return queue_var_show(q->nr_requests, (page));
  36 }
  37
  38 static ssize_t
  39 queue_requests_store(struct request_queue *q, const char *page, size_t count)
  40 {
  41         struct request_list *rl = &q->rq;
  42         unsigned long nr;
  43         int ret;
  44
  45         if (!q->request_fn)
  46                 return -EINVAL;
  47
  48         ret = queue_var_store(&nr, page, count);
  49         if (nr < BLKDEV_MIN_RQ)
  50                 nr = BLKDEV_MIN_RQ;
  51
  52         spin_lock_irq(q->queue_lock);
  53         q->nr_requests = nr;
  54         blk_queue_congestion_threshold(q);
  55
  56         if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
  57                 blk_set_queue_congested(q, BLK_RW_SYNC);
  58         else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
  59                 blk_clear_queue_congested(q, BLK_RW_SYNC);
  60
  61         if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
  62                 blk_set_queue_congested(q, BLK_RW_ASYNC);
  63         else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
  64                 blk_clear_queue_congested(q, BLK_RW_ASYNC);
  65
  66         if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
  67                 blk_set_queue_full(q, BLK_RW_SYNC);
  68         } else if (rl->count[BLK_RW_SYNC]+1 <= q->nr_requests) {
  69                 blk_clear_queue_full(q, BLK_RW_SYNC);
  70                 wake_up(&rl->wait[BLK_RW_SYNC]);
  71         }
  72
  73         if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
  74                 blk_set_queue_full(q, BLK_RW_ASYNC);
  75         } else if (rl->count[BLK_RW_ASYNC]+1 <= q->nr_requests) {
  76                 blk_clear_queue_full(q, BLK_RW_ASYNC);
  77                 wake_up(&rl->wait[BLK_RW_ASYNC]);
  78         }
  79         spin_unlock_irq(q->queue_lock);
  80         return ret;
  81 }
  82
  83 static ssize_t queue_ra_show(struct request_queue *q, char *page)
  84 {
  85         unsigned long ra_kb = q->backing_dev_info.ra_pages <<
  86                                         (PAGE_CACHE_SHIFT - 10);
  87
  88         return queue_var_show(ra_kb, (page));
  89 }
  90
  91 static ssize_t
  92 queue_ra_store(struct request_queue *q, const char *page, size_t count)
  93 {
  94         unsigned long ra_kb;
  95         ssize_t ret = queue_var_store(&ra_kb, page, count);
  96
  97         q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
  98
  99         return ret;
 100 }
 101
 102 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
 103 {
 104         int max_sectors_kb = queue_max_sectors(q) >> 1;
 105
 106         return queue_var_show(max_sectors_kb, (page));
 107 }
 108
 109 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
 110 {
 111         return queue_var_show(queue_max_segments(q), (page));
 112 }
 113
 114 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 115 {
 116         if (test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags))
 117                 return queue_var_show(queue_max_segment_size(q), (page));
 118
 119         return queue_var_show(PAGE_CACHE_SIZE, (page));
 120 }
 121
 122 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 123 {
 124         return queue_var_show(queue_logical_block_size(q), page);
 125 }
 126
 127 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 128 {
 129         return queue_var_show(queue_physical_block_size(q), page);
 130 }
 131
 132 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 133 {
 134         return queue_var_show(queue_io_min(q), page);
 135 }
 136
 137 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 138 {
 139         return queue_var_show(queue_io_opt(q), page);
 140 }
 141
 142 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 143 {
 144         return queue_var_show(q->limits.discard_granularity, page);
 145 }
 146
 147 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 148 {
 149         return queue_var_show(q->limits.max_discard_sectors << 9, page);
 150 }
 151
 152 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 153 {
 154         return queue_var_show(queue_discard_zeroes_data(q), page);
 155 }
 156
 157 static ssize_t
 158 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 159 {
 160         unsigned long max_sectors_kb,
 161                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 162                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
 163         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 164
 165         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 166                 return -EINVAL;
 167
 168         spin_lock_irq(q->queue_lock);
 169         q->limits.max_sectors = max_sectors_kb << 1;
 170         spin_unlock_irq(q->queue_lock);
 171
 172         return ret;
 173 }
 174
 175 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 176 {
 177         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 178
 179         return queue_var_show(max_hw_sectors_kb, (page));
 180 }
 181
 182 static ssize_t queue_nonrot_show(struct request_queue *q, char *page)
 183 {
 184         return queue_var_show(!blk_queue_nonrot(q), page);
 185 }
 186
 187 static ssize_t queue_nonrot_store(struct request_queue *q, const char *page,
 188                                   size_t count)
 189 {
 190         unsigned long nm;
 191         ssize_t ret = queue_var_store(&nm, page, count);
 192
 193         spin_lock_irq(q->queue_lock);
 194         if (nm)
 195                 queue_flag_clear(QUEUE_FLAG_NONROT, q);
 196         else
 197                 queue_flag_set(QUEUE_FLAG_NONROT, q);
 198         spin_unlock_irq(q->queue_lock);
 199
 200         return ret;
 201 }
 202
 203 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 204 {
 205         return queue_var_show((blk_queue_nomerges(q) << 1) |
 206                                blk_queue_noxmerges(q), page);
 207 }
 208
 209 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 210                                     size_t count)
 211 {
 212         unsigned long nm;
 213         ssize_t ret = queue_var_store(&nm, page, count);
 214
 215         spin_lock_irq(q->queue_lock);
 216         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 217         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 218         if (nm == 2)
 219                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 220         else if (nm)
 221                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 222         spin_unlock_irq(q->queue_lock);
 223
 224         return ret;
 225 }
 226
 227 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 228 {
 229         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 230
 231         return queue_var_show(set, page);
 232 }
 233
 234 static ssize_t
 235 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 236 {
 237         ssize_t ret = -EINVAL;
 238 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
 239         unsigned long val;
 240
 241         ret = queue_var_store(&val, page, count);
 242         spin_lock_irq(q->queue_lock);
 243         if (val)
 244                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 245         else
 246                 queue_flag_clear(QUEUE_FLAG_SAME_COMP,  q);
 247         spin_unlock_irq(q->queue_lock);
 248 #endif
 249         return ret;
 250 }
 251
 252 static ssize_t queue_iostats_show(struct request_queue *q, char *page)
 253 {
 254         return queue_var_show(blk_queue_io_stat(q), page);
 255 }
 256
 257 static ssize_t queue_iostats_store(struct request_queue *q, const char *page,
 258                                    size_t count)
 259 {
 260         unsigned long stats;
 261         ssize_t ret = queue_var_store(&stats, page, count);
 262
 263         spin_lock_irq(q->queue_lock);
 264         if (stats)
 265                 queue_flag_set(QUEUE_FLAG_IO_STAT, q);
 266         else
 267                 queue_flag_clear(QUEUE_FLAG_IO_STAT, q);
 268         spin_unlock_irq(q->queue_lock);
 269
 270         return ret;
 271 }
 272
 273 static struct queue_sysfs_entry queue_requests_entry = {
 274         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 275         .show = queue_requests_show,
 276         .store = queue_requests_store,
 277 };
 278
 279 static struct queue_sysfs_entry queue_ra_entry = {
 280         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 281         .show = queue_ra_show,
 282         .store = queue_ra_store,
 283 };
 284
 285 static struct queue_sysfs_entry queue_max_sectors_entry = {
 286         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 287         .show = queue_max_sectors_show,
 288         .store = queue_max_sectors_store,
 289 };
 290
 291 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 292         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 293         .show = queue_max_hw_sectors_show,
 294 };
 295
 296 static struct queue_sysfs_entry queue_max_segments_entry = {
 297         .attr = {.name = "max_segments", .mode = S_IRUGO },
 298         .show = queue_max_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_nonrot_show,
 355         .store = queue_nonrot_store,
 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_iostats_show,
 373         .store = queue_iostats_store,
 374 };
 375
 376 static struct attribute *default_attrs[] = {
 377         &queue_requests_entry.attr,
 378         &queue_ra_entry.attr,
 379         &queue_max_hw_sectors_entry.attr,
 380         &queue_max_sectors_entry.attr,
 381         &queue_max_segments_entry.attr,
 382         &queue_max_segment_size_entry.attr,
 383         &queue_iosched_entry.attr,
 384         &queue_hw_sector_size_entry.attr,
 385         &queue_logical_block_size_entry.attr,
 386         &queue_physical_block_size_entry.attr,
 387         &queue_io_min_entry.attr,
 388         &queue_io_opt_entry.attr,
 389         &queue_discard_granularity_entry.attr,
 390         &queue_discard_max_entry.attr,
 391         &queue_discard_zeroes_data_entry.attr,
 392         &queue_nonrot_entry.attr,
 393         &queue_nomerges_entry.attr,
 394         &queue_rq_affinity_entry.attr,
 395         &queue_iostats_entry.attr,
 396         NULL,
 397 };
 398
 399 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 400
 401 static ssize_t
 402 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 403 {
 404         struct queue_sysfs_entry *entry = to_queue(attr);
 405         struct request_queue *q =
 406                 container_of(kobj, struct request_queue, kobj);
 407         ssize_t res;
 408
 409         if (!entry->show)
 410                 return -EIO;
 411         mutex_lock(&q->sysfs_lock);
 412         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 413                 mutex_unlock(&q->sysfs_lock);
 414                 return -ENOENT;
 415         }
 416         res = entry->show(q, page);
 417         mutex_unlock(&q->sysfs_lock);
 418         return res;
 419 }
 420
 421 static ssize_t
 422 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 423                     const char *page, size_t length)
 424 {
 425         struct queue_sysfs_entry *entry = to_queue(attr);
 426         struct request_queue *q;
 427         ssize_t res;
 428
 429         if (!entry->store)
 430                 return -EIO;
 431
 432         q = container_of(kobj, struct request_queue, kobj);
 433         mutex_lock(&q->sysfs_lock);
 434         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 435                 mutex_unlock(&q->sysfs_lock);
 436                 return -ENOENT;
 437         }
 438         res = entry->store(q, page, length);
 439         mutex_unlock(&q->sysfs_lock);
 440         return res;
 441 }
 442
 443 /**
 444  * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
 445  * @kobj:    the kobj belonging of the request queue to be released
 446  *
 447  * Description:
 448  *     blk_cleanup_queue is the pair to blk_init_queue() or
 449  *     blk_queue_make_request().  It should be called when a request queue is
 450  *     being released; typically when a block device is being de-registered.
 451  *     Currently, its primary task it to free all the &struct request
 452  *     structures that were allocated to the queue and the queue itself.
 453  *
 454  * Caveat:
 455  *     Hopefully the low level driver will have finished any
 456  *     outstanding requests first...
 457  **/
 458 static void blk_release_queue(struct kobject *kobj)
 459 {
 460         struct request_queue *q =
 461                 container_of(kobj, struct request_queue, kobj);
 462         struct request_list *rl = &q->rq;
 463
 464         blk_sync_queue(q);
 465
 466         if (rl->rq_pool)
 467                 mempool_destroy(rl->rq_pool);
 468
 469         if (q->queue_tags)
 470                 __blk_queue_free_tags(q);
 471
 472         blk_trace_shutdown(q);
 473
 474         bdi_destroy(&q->backing_dev_info);
 475         kmem_cache_free(blk_requestq_cachep, q);
 476 }
 477
 478 static const struct sysfs_ops queue_sysfs_ops = {
 479         .show   = queue_attr_show,
 480         .store  = queue_attr_store,
 481 };
 482
 483 struct kobj_type blk_queue_ktype = {
 484         .sysfs_ops      = &queue_sysfs_ops,
 485         .default_attrs  = default_attrs,
 486         .release        = blk_release_queue,
 487 };
 488
 489 int blk_register_queue(struct gendisk *disk)
 490 {
 491         int ret;
 492         struct device *dev = disk_to_dev(disk);
 493
 494         struct request_queue *q = disk->queue;
 495
 496         if (WARN_ON(!q))
 497                 return -ENXIO;
 498
 499         ret = blk_trace_init_sysfs(dev);
 500         if (ret)
 501                 return ret;
 502
 503         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 504         if (ret < 0)
 505                 return ret;
 506
 507         kobject_uevent(&q->kobj, KOBJ_ADD);
 508
 509         if (!q->request_fn)
 510                 return 0;
 511
 512         ret = elv_register_queue(q);
 513         if (ret) {
 514                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 515                 kobject_del(&q->kobj);
 516                 blk_trace_remove_sysfs(disk_to_dev(disk));
 517                 return ret;
 518         }
 519
 520         return 0;
 521 }
 522
 523 void blk_unregister_queue(struct gendisk *disk)
 524 {
 525         struct request_queue *q = disk->queue;
 526
 527         if (WARN_ON(!q))
 528                 return;
 529
 530         if (q->request_fn)
 531                 elv_unregister_queue(q);
 532
 533         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 534         kobject_del(&q->kobj);
 535         blk_trace_remove_sysfs(disk_to_dev(disk));
 536         kobject_put(&disk_to_dev(disk)->kobj);
 537 }