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