block/blk-sysfs.c

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