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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_logical_block_size_show(struct request_queue *q, char *page)
 110 {
 111         return queue_var_show(queue_logical_block_size(q), page);
 112 }
 113
 114 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 115 {
 116         return queue_var_show(queue_physical_block_size(q), page);
 117 }
 118
 119 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 120 {
 121         return queue_var_show(queue_io_min(q), page);
 122 }
 123
 124 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 125 {
 126         return queue_var_show(queue_io_opt(q), page);
 127 }
 128
 129 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 130 {
 131         return queue_var_show(q->limits.discard_granularity, page);
 132 }
 133
 134 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 135 {
 136         return queue_var_show(q->limits.max_discard_sectors << 9, page);
 137 }
 138
 139 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 140 {
 141         return queue_var_show(queue_discard_zeroes_data(q), page);
 142 }
 143
 144 static ssize_t
 145 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 146 {
 147         unsigned long max_sectors_kb,
 148                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 149                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
 150         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 151
 152         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 153                 return -EINVAL;
 154
 155         spin_lock_irq(q->queue_lock);
 156         q->limits.max_sectors = max_sectors_kb << 1;
 157         spin_unlock_irq(q->queue_lock);
 158
 159         return ret;
 160 }
 161
 162 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 163 {
 164         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 165
 166         return queue_var_show(max_hw_sectors_kb, (page));
 167 }
 168
 169 static ssize_t queue_nonrot_show(struct request_queue *q, char *page)
 170 {
 171         return queue_var_show(!blk_queue_nonrot(q), page);
 172 }
 173
 174 static ssize_t queue_nonrot_store(struct request_queue *q, const char *page,
 175                                   size_t count)
 176 {
 177         unsigned long nm;
 178         ssize_t ret = queue_var_store(&nm, page, count);
 179
 180         spin_lock_irq(q->queue_lock);
 181         if (nm)
 182                 queue_flag_clear(QUEUE_FLAG_NONROT, q);
 183         else
 184                 queue_flag_set(QUEUE_FLAG_NONROT, q);
 185         spin_unlock_irq(q->queue_lock);
 186
 187         return ret;
 188 }
 189
 190 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 191 {
 192         return queue_var_show(blk_queue_nomerges(q), page);
 193 }
 194
 195 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 196                                     size_t count)
 197 {
 198         unsigned long nm;
 199         ssize_t ret = queue_var_store(&nm, page, count);
 200
 201         spin_lock_irq(q->queue_lock);
 202         if (nm)
 203                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 204         else
 205                 queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 206         spin_unlock_irq(q->queue_lock);
 207
 208         return ret;
 209 }
 210
 211 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 212 {
 213         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 214
 215         return queue_var_show(set, page);
 216 }
 217
 218 static ssize_t
 219 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 220 {
 221         ssize_t ret = -EINVAL;
 222 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
 223         unsigned long val;
 224
 225         ret = queue_var_store(&val, page, count);
 226         spin_lock_irq(q->queue_lock);
 227         if (val)
 228                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 229         else
 230                 queue_flag_clear(QUEUE_FLAG_SAME_COMP,  q);
 231         spin_unlock_irq(q->queue_lock);
 232 #endif
 233         return ret;
 234 }
 235
 236 static ssize_t queue_iostats_show(struct request_queue *q, char *page)
 237 {
 238         return queue_var_show(blk_queue_io_stat(q), page);
 239 }
 240
 241 static ssize_t queue_iostats_store(struct request_queue *q, const char *page,
 242                                    size_t count)
 243 {
 244         unsigned long stats;
 245         ssize_t ret = queue_var_store(&stats, page, count);
 246
 247         spin_lock_irq(q->queue_lock);
 248         if (stats)
 249                 queue_flag_set(QUEUE_FLAG_IO_STAT, q);
 250         else
 251                 queue_flag_clear(QUEUE_FLAG_IO_STAT, q);
 252         spin_unlock_irq(q->queue_lock);
 253
 254         return ret;
 255 }
 256
 257 static struct queue_sysfs_entry queue_requests_entry = {
 258         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 259         .show = queue_requests_show,
 260         .store = queue_requests_store,
 261 };
 262
 263 static struct queue_sysfs_entry queue_ra_entry = {
 264         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 265         .show = queue_ra_show,
 266         .store = queue_ra_store,
 267 };
 268
 269 static struct queue_sysfs_entry queue_max_sectors_entry = {
 270         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 271         .show = queue_max_sectors_show,
 272         .store = queue_max_sectors_store,
 273 };
 274
 275 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 276         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 277         .show = queue_max_hw_sectors_show,
 278 };
 279
 280 static struct queue_sysfs_entry queue_iosched_entry = {
 281         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 282         .show = elv_iosched_show,
 283         .store = elv_iosched_store,
 284 };
 285
 286 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 287         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 288         .show = queue_logical_block_size_show,
 289 };
 290
 291 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 292         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 293         .show = queue_logical_block_size_show,
 294 };
 295
 296 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 297         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 298         .show = queue_physical_block_size_show,
 299 };
 300
 301 static struct queue_sysfs_entry queue_io_min_entry = {
 302         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 303         .show = queue_io_min_show,
 304 };
 305
 306 static struct queue_sysfs_entry queue_io_opt_entry = {
 307         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 308         .show = queue_io_opt_show,
 309 };
 310
 311 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 312         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
 313         .show = queue_discard_granularity_show,
 314 };
 315
 316 static struct queue_sysfs_entry queue_discard_max_entry = {
 317         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
 318         .show = queue_discard_max_show,
 319 };
 320
 321 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 322         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
 323         .show = queue_discard_zeroes_data_show,
 324 };
 325
 326 static struct queue_sysfs_entry queue_nonrot_entry = {
 327         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 328         .show = queue_nonrot_show,
 329         .store = queue_nonrot_store,
 330 };
 331
 332 static struct queue_sysfs_entry queue_nomerges_entry = {
 333         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 334         .show = queue_nomerges_show,
 335         .store = queue_nomerges_store,
 336 };
 337
 338 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 339         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 340         .show = queue_rq_affinity_show,
 341         .store = queue_rq_affinity_store,
 342 };
 343
 344 static struct queue_sysfs_entry queue_iostats_entry = {
 345         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 346         .show = queue_iostats_show,
 347         .store = queue_iostats_store,
 348 };
 349
 350 static struct attribute *default_attrs[] = {
 351         &queue_requests_entry.attr,
 352         &queue_ra_entry.attr,
 353         &queue_max_hw_sectors_entry.attr,
 354         &queue_max_sectors_entry.attr,
 355         &queue_iosched_entry.attr,
 356         &queue_hw_sector_size_entry.attr,
 357         &queue_logical_block_size_entry.attr,
 358         &queue_physical_block_size_entry.attr,
 359         &queue_io_min_entry.attr,
 360         &queue_io_opt_entry.attr,
 361         &queue_discard_granularity_entry.attr,
 362         &queue_discard_max_entry.attr,
 363         &queue_discard_zeroes_data_entry.attr,
 364         &queue_nonrot_entry.attr,
 365         &queue_nomerges_entry.attr,
 366         &queue_rq_affinity_entry.attr,
 367         &queue_iostats_entry.attr,
 368         NULL,
 369 };
 370
 371 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 372
 373 static ssize_t
 374 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 375 {
 376         struct queue_sysfs_entry *entry = to_queue(attr);
 377         struct request_queue *q =
 378                 container_of(kobj, struct request_queue, kobj);
 379         ssize_t res;
 380
 381         if (!entry->show)
 382                 return -EIO;
 383         mutex_lock(&q->sysfs_lock);
 384         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 385                 mutex_unlock(&q->sysfs_lock);
 386                 return -ENOENT;
 387         }
 388         res = entry->show(q, page);
 389         mutex_unlock(&q->sysfs_lock);
 390         return res;
 391 }
 392
 393 static ssize_t
 394 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 395                     const char *page, size_t length)
 396 {
 397         struct queue_sysfs_entry *entry = to_queue(attr);
 398         struct request_queue *q;
 399         ssize_t res;
 400
 401         if (!entry->store)
 402                 return -EIO;
 403
 404         q = container_of(kobj, struct request_queue, kobj);
 405         mutex_lock(&q->sysfs_lock);
 406         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 407                 mutex_unlock(&q->sysfs_lock);
 408                 return -ENOENT;
 409         }
 410         res = entry->store(q, page, length);
 411         mutex_unlock(&q->sysfs_lock);
 412         return res;
 413 }
 414
 415 /**
 416  * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
 417  * @kobj:    the kobj belonging of the request queue to be released
 418  *
 419  * Description:
 420  *     blk_cleanup_queue is the pair to blk_init_queue() or
 421  *     blk_queue_make_request().  It should be called when a request queue is
 422  *     being released; typically when a block device is being de-registered.
 423  *     Currently, its primary task it to free all the &struct request
 424  *     structures that were allocated to the queue and the queue itself.
 425  *
 426  * Caveat:
 427  *     Hopefully the low level driver will have finished any
 428  *     outstanding requests first...
 429  **/
 430 static void blk_release_queue(struct kobject *kobj)
 431 {
 432         struct request_queue *q =
 433                 container_of(kobj, struct request_queue, kobj);
 434         struct request_list *rl = &q->rq;
 435
 436         blk_sync_queue(q);
 437
 438         if (rl->rq_pool)
 439                 mempool_destroy(rl->rq_pool);
 440
 441         if (q->queue_tags)
 442                 __blk_queue_free_tags(q);
 443
 444         blk_trace_shutdown(q);
 445
 446         bdi_destroy(&q->backing_dev_info);
 447         kmem_cache_free(blk_requestq_cachep, q);
 448 }
 449
 450 static struct sysfs_ops queue_sysfs_ops = {
 451         .show   = queue_attr_show,
 452         .store  = queue_attr_store,
 453 };
 454
 455 struct kobj_type blk_queue_ktype = {
 456         .sysfs_ops      = &queue_sysfs_ops,
 457         .default_attrs  = default_attrs,
 458         .release        = blk_release_queue,
 459 };
 460
 461 int blk_register_queue(struct gendisk *disk)
 462 {
 463         int ret;
 464         struct device *dev = disk_to_dev(disk);
 465
 466         struct request_queue *q = disk->queue;
 467
 468         if (WARN_ON(!q))
 469                 return -ENXIO;
 470
 471         ret = blk_trace_init_sysfs(dev);
 472         if (ret)
 473                 return ret;
 474
 475         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 476         if (ret < 0)
 477                 return ret;
 478
 479         kobject_uevent(&q->kobj, KOBJ_ADD);
 480
 481         if (!q->request_fn)
 482                 return 0;
 483
 484         ret = elv_register_queue(q);
 485         if (ret) {
 486                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 487                 kobject_del(&q->kobj);
 488                 blk_trace_remove_sysfs(disk_to_dev(disk));
 489                 return ret;
 490         }
 491
 492         return 0;
 493 }
 494
 495 void blk_unregister_queue(struct gendisk *disk)
 496 {
 497         struct request_queue *q = disk->queue;
 498
 499         if (WARN_ON(!q))
 500                 return;
 501
 502         if (q->request_fn)
 503                 elv_unregister_queue(q);
 504
 505         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 506         kobject_del(&q->kobj);
 507         blk_trace_remove_sysfs(disk_to_dev(disk));
 508         kobject_put(&disk_to_dev(disk)->kobj);
 509 }