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   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_logical_block_size_show(struct request_queue *q, char *page)
 111 {
 112         return queue_var_show(queue_logical_block_size(q), page);
 113 }
 114
 115 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 116 {
 117         return queue_var_show(queue_physical_block_size(q), page);
 118 }
 119
 120 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 121 {
 122         return queue_var_show(queue_io_min(q), page);
 123 }
 124
 125 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 126 {
 127         return queue_var_show(queue_io_opt(q), page);
 128 }
 129
 130 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 131 {
 132         return queue_var_show(q->limits.discard_granularity, page);
 133 }
 134
 135 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 136 {
 137         return queue_var_show(q->limits.max_discard_sectors << 9, page);
 138 }
 139
 140 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 141 {
 142         return queue_var_show(queue_discard_zeroes_data(q), page);
 143 }
 144
 145 static ssize_t
 146 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 147 {
 148         unsigned long max_sectors_kb,
 149                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 150                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
 151         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 152
 153         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 154                 return -EINVAL;
 155
 156         spin_lock_irq(q->queue_lock);
 157         q->limits.max_sectors = max_sectors_kb << 1;
 158         spin_unlock_irq(q->queue_lock);
 159
 160         return ret;
 161 }
 162
 163 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 164 {
 165         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 166
 167         return queue_var_show(max_hw_sectors_kb, (page));
 168 }
 169
 170 static ssize_t queue_nonrot_show(struct request_queue *q, char *page)
 171 {
 172         return queue_var_show(!blk_queue_nonrot(q), page);
 173 }
 174
 175 static ssize_t queue_nonrot_store(struct request_queue *q, const char *page,
 176                                   size_t count)
 177 {
 178         unsigned long nm;
 179         ssize_t ret = queue_var_store(&nm, page, count);
 180
 181         spin_lock_irq(q->queue_lock);
 182         if (nm)
 183                 queue_flag_clear(QUEUE_FLAG_NONROT, q);
 184         else
 185                 queue_flag_set(QUEUE_FLAG_NONROT, q);
 186         spin_unlock_irq(q->queue_lock);
 187
 188         return ret;
 189 }
 190
 191 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 192 {
 193         return queue_var_show((blk_queue_nomerges(q) << 1) |
 194                                blk_queue_noxmerges(q), page);
 195 }
 196
 197 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 198                                     size_t count)
 199 {
 200         unsigned long nm;
 201         ssize_t ret = queue_var_store(&nm, page, count);
 202
 203         spin_lock_irq(q->queue_lock);
 204         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 205         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 206         if (nm == 2)
 207                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 208         else if (nm)
 209                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 210         spin_unlock_irq(q->queue_lock);
 211
 212         return ret;
 213 }
 214
 215 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 216 {
 217         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 218
 219         return queue_var_show(set, page);
 220 }
 221
 222 static ssize_t
 223 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 224 {
 225         ssize_t ret = -EINVAL;
 226 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
 227         unsigned long val;
 228
 229         ret = queue_var_store(&val, page, count);
 230         spin_lock_irq(q->queue_lock);
 231         if (val)
 232                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 233         else
 234                 queue_flag_clear(QUEUE_FLAG_SAME_COMP,  q);
 235         spin_unlock_irq(q->queue_lock);
 236 #endif
 237         return ret;
 238 }
 239
 240 static ssize_t queue_iostats_show(struct request_queue *q, char *page)
 241 {
 242         return queue_var_show(blk_queue_io_stat(q), page);
 243 }
 244
 245 static ssize_t queue_iostats_store(struct request_queue *q, const char *page,
 246                                    size_t count)
 247 {
 248         unsigned long stats;
 249         ssize_t ret = queue_var_store(&stats, page, count);
 250
 251         spin_lock_irq(q->queue_lock);
 252         if (stats)
 253                 queue_flag_set(QUEUE_FLAG_IO_STAT, q);
 254         else
 255                 queue_flag_clear(QUEUE_FLAG_IO_STAT, q);
 256         spin_unlock_irq(q->queue_lock);
 257
 258         return ret;
 259 }
 260
 261 static struct queue_sysfs_entry queue_requests_entry = {
 262         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 263         .show = queue_requests_show,
 264         .store = queue_requests_store,
 265 };
 266
 267 static struct queue_sysfs_entry queue_ra_entry = {
 268         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 269         .show = queue_ra_show,
 270         .store = queue_ra_store,
 271 };
 272
 273 static struct queue_sysfs_entry queue_max_sectors_entry = {
 274         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 275         .show = queue_max_sectors_show,
 276         .store = queue_max_sectors_store,
 277 };
 278
 279 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 280         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 281         .show = queue_max_hw_sectors_show,
 282 };
 283
 284 static struct queue_sysfs_entry queue_iosched_entry = {
 285         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 286         .show = elv_iosched_show,
 287         .store = elv_iosched_store,
 288 };
 289
 290 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 291         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 292         .show = queue_logical_block_size_show,
 293 };
 294
 295 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 296         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 297         .show = queue_logical_block_size_show,
 298 };
 299
 300 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 301         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 302         .show = queue_physical_block_size_show,
 303 };
 304
 305 static struct queue_sysfs_entry queue_io_min_entry = {
 306         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 307         .show = queue_io_min_show,
 308 };
 309
 310 static struct queue_sysfs_entry queue_io_opt_entry = {
 311         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 312         .show = queue_io_opt_show,
 313 };
 314
 315 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 316         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
 317         .show = queue_discard_granularity_show,
 318 };
 319
 320 static struct queue_sysfs_entry queue_discard_max_entry = {
 321         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
 322         .show = queue_discard_max_show,
 323 };
 324
 325 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 326         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
 327         .show = queue_discard_zeroes_data_show,
 328 };
 329
 330 static struct queue_sysfs_entry queue_nonrot_entry = {
 331         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 332         .show = queue_nonrot_show,
 333         .store = queue_nonrot_store,
 334 };
 335
 336 static struct queue_sysfs_entry queue_nomerges_entry = {
 337         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 338         .show = queue_nomerges_show,
 339         .store = queue_nomerges_store,
 340 };
 341
 342 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 343         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 344         .show = queue_rq_affinity_show,
 345         .store = queue_rq_affinity_store,
 346 };
 347
 348 static struct queue_sysfs_entry queue_iostats_entry = {
 349         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 350         .show = queue_iostats_show,
 351         .store = queue_iostats_store,
 352 };
 353
 354 static struct attribute *default_attrs[] = {
 355         &queue_requests_entry.attr,
 356         &queue_ra_entry.attr,
 357         &queue_max_hw_sectors_entry.attr,
 358         &queue_max_sectors_entry.attr,
 359         &queue_iosched_entry.attr,
 360         &queue_hw_sector_size_entry.attr,
 361         &queue_logical_block_size_entry.attr,
 362         &queue_physical_block_size_entry.attr,
 363         &queue_io_min_entry.attr,
 364         &queue_io_opt_entry.attr,
 365         &queue_discard_granularity_entry.attr,
 366         &queue_discard_max_entry.attr,
 367         &queue_discard_zeroes_data_entry.attr,
 368         &queue_nonrot_entry.attr,
 369         &queue_nomerges_entry.attr,
 370         &queue_rq_affinity_entry.attr,
 371         &queue_iostats_entry.attr,
 372         NULL,
 373 };
 374
 375 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 376
 377 static ssize_t
 378 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 379 {
 380         struct queue_sysfs_entry *entry = to_queue(attr);
 381         struct request_queue *q =
 382                 container_of(kobj, struct request_queue, kobj);
 383         ssize_t res;
 384
 385         if (!entry->show)
 386                 return -EIO;
 387         mutex_lock(&q->sysfs_lock);
 388         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 389                 mutex_unlock(&q->sysfs_lock);
 390                 return -ENOENT;
 391         }
 392         res = entry->show(q, page);
 393         mutex_unlock(&q->sysfs_lock);
 394         return res;
 395 }
 396
 397 static ssize_t
 398 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 399                     const char *page, size_t length)
 400 {
 401         struct queue_sysfs_entry *entry = to_queue(attr);
 402         struct request_queue *q;
 403         ssize_t res;
 404
 405         if (!entry->store)
 406                 return -EIO;
 407
 408         q = container_of(kobj, struct request_queue, kobj);
 409         mutex_lock(&q->sysfs_lock);
 410         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 411                 mutex_unlock(&q->sysfs_lock);
 412                 return -ENOENT;
 413         }
 414         res = entry->store(q, page, length);
 415         mutex_unlock(&q->sysfs_lock);
 416         return res;
 417 }
 418
 419 /**
 420  * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
 421  * @kobj:    the kobj belonging of the request queue to be released
 422  *
 423  * Description:
 424  *     blk_cleanup_queue is the pair to blk_init_queue() or
 425  *     blk_queue_make_request().  It should be called when a request queue is
 426  *     being released; typically when a block device is being de-registered.
 427  *     Currently, its primary task it to free all the &struct request
 428  *     structures that were allocated to the queue and the queue itself.
 429  *
 430  * Caveat:
 431  *     Hopefully the low level driver will have finished any
 432  *     outstanding requests first...
 433  **/
 434 static void blk_release_queue(struct kobject *kobj)
 435 {
 436         struct request_queue *q =
 437                 container_of(kobj, struct request_queue, kobj);
 438         struct request_list *rl = &q->rq;
 439
 440         blk_sync_queue(q);
 441
 442         if (rl->rq_pool)
 443                 mempool_destroy(rl->rq_pool);
 444
 445         if (q->queue_tags)
 446                 __blk_queue_free_tags(q);
 447
 448         blk_trace_shutdown(q);
 449
 450         bdi_destroy(&q->backing_dev_info);
 451         kmem_cache_free(blk_requestq_cachep, q);
 452 }
 453
 454 static const struct sysfs_ops queue_sysfs_ops = {
 455         .show   = queue_attr_show,
 456         .store  = queue_attr_store,
 457 };
 458
 459 struct kobj_type blk_queue_ktype = {
 460         .sysfs_ops      = &queue_sysfs_ops,
 461         .default_attrs  = default_attrs,
 462         .release        = blk_release_queue,
 463 };
 464
 465 int blk_register_queue(struct gendisk *disk)
 466 {
 467         int ret;
 468         struct device *dev = disk_to_dev(disk);
 469
 470         struct request_queue *q = disk->queue;
 471
 472         if (WARN_ON(!q))
 473                 return -ENXIO;
 474
 475         ret = blk_trace_init_sysfs(dev);
 476         if (ret)
 477                 return ret;
 478
 479         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 480         if (ret < 0)
 481                 return ret;
 482
 483         kobject_uevent(&q->kobj, KOBJ_ADD);
 484
 485         if (!q->request_fn)
 486                 return 0;
 487
 488         ret = elv_register_queue(q);
 489         if (ret) {
 490                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 491                 kobject_del(&q->kobj);
 492                 blk_trace_remove_sysfs(disk_to_dev(disk));
 493                 return ret;
 494         }
 495
 496         return 0;
 497 }
 498
 499 void blk_unregister_queue(struct gendisk *disk)
 500 {
 501         struct request_queue *q = disk->queue;
 502
 503         if (WARN_ON(!q))
 504                 return;
 505
 506         if (q->request_fn)
 507                 elv_unregister_queue(q);
 508
 509         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 510         kobject_del(&q->kobj);
 511         blk_trace_remove_sysfs(disk_to_dev(disk));
 512         kobject_put(&disk_to_dev(disk)->kobj);
 513 }