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 = queue_var_store(&nr, page, count);
  44         if (nr < BLKDEV_MIN_RQ)
  45                 nr = BLKDEV_MIN_RQ;
  46
  47         spin_lock_irq(q->queue_lock);
  48         q->nr_requests = nr;
  49         blk_queue_congestion_threshold(q);
  50
  51         if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
  52                 blk_set_queue_congested(q, BLK_RW_SYNC);
  53         else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
  54                 blk_clear_queue_congested(q, BLK_RW_SYNC);
  55
  56         if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
  57                 blk_set_queue_congested(q, BLK_RW_ASYNC);
  58         else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
  59                 blk_clear_queue_congested(q, BLK_RW_ASYNC);
  60
  61         if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
  62                 blk_set_queue_full(q, BLK_RW_SYNC);
  63         } else if (rl->count[BLK_RW_SYNC]+1 <= q->nr_requests) {
  64                 blk_clear_queue_full(q, BLK_RW_SYNC);
  65                 wake_up(&rl->wait[BLK_RW_SYNC]);
  66         }
  67
  68         if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
  69                 blk_set_queue_full(q, BLK_RW_ASYNC);
  70         } else if (rl->count[BLK_RW_ASYNC]+1 <= q->nr_requests) {
  71                 blk_clear_queue_full(q, BLK_RW_ASYNC);
  72                 wake_up(&rl->wait[BLK_RW_ASYNC]);
  73         }
  74         spin_unlock_irq(q->queue_lock);
  75         return ret;
  76 }
  77
  78 static ssize_t queue_ra_show(struct request_queue *q, char *page)
  79 {
  80         unsigned long ra_kb = q->backing_dev_info.ra_pages <<
  81                                         (PAGE_CACHE_SHIFT - 10);
  82
  83         return queue_var_show(ra_kb, (page));
  84 }
  85
  86 static ssize_t
  87 queue_ra_store(struct request_queue *q, const char *page, size_t count)
  88 {
  89         unsigned long ra_kb;
  90         ssize_t ret = queue_var_store(&ra_kb, page, count);
  91
  92         q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
  93
  94         return ret;
  95 }
  96
  97 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
  98 {
  99         int max_sectors_kb = queue_max_sectors(q) >> 1;
 100
 101         return queue_var_show(max_sectors_kb, (page));
 102 }
 103
 104 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 105 {
 106         return queue_var_show(queue_logical_block_size(q), page);
 107 }
 108
 109 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 110 {
 111         return queue_var_show(queue_physical_block_size(q), page);
 112 }
 113
 114 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 115 {
 116         return queue_var_show(queue_io_min(q), page);
 117 }
 118
 119 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 120 {
 121         return queue_var_show(queue_io_opt(q), page);
 122 }
 123
 124 static ssize_t
 125 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 126 {
 127         unsigned long max_sectors_kb,
 128                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 129                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
 130         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 131
 132         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 133                 return -EINVAL;
 134
 135         spin_lock_irq(q->queue_lock);
 136         blk_queue_max_sectors(q, max_sectors_kb << 1);
 137         spin_unlock_irq(q->queue_lock);
 138
 139         return ret;
 140 }
 141
 142 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 143 {
 144         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 145
 146         return queue_var_show(max_hw_sectors_kb, (page));
 147 }
 148
 149 static ssize_t queue_nonrot_show(struct request_queue *q, char *page)
 150 {
 151         return queue_var_show(!blk_queue_nonrot(q), page);
 152 }
 153
 154 static ssize_t queue_nonrot_store(struct request_queue *q, const char *page,
 155                                   size_t count)
 156 {
 157         unsigned long nm;
 158         ssize_t ret = queue_var_store(&nm, page, count);
 159
 160         spin_lock_irq(q->queue_lock);
 161         if (nm)
 162                 queue_flag_clear(QUEUE_FLAG_NONROT, q);
 163         else
 164                 queue_flag_set(QUEUE_FLAG_NONROT, q);
 165         spin_unlock_irq(q->queue_lock);
 166
 167         return ret;
 168 }
 169
 170 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 171 {
 172         return queue_var_show(blk_queue_nomerges(q), page);
 173 }
 174
 175 static ssize_t queue_nomerges_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_set(QUEUE_FLAG_NOMERGES, q);
 184         else
 185                 queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 186         spin_unlock_irq(q->queue_lock);
 187
 188         return ret;
 189 }
 190
 191 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 192 {
 193         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 194
 195         return queue_var_show(set, page);
 196 }
 197
 198 static ssize_t
 199 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 200 {
 201         ssize_t ret = -EINVAL;
 202 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
 203         unsigned long val;
 204
 205         ret = queue_var_store(&val, page, count);
 206         spin_lock_irq(q->queue_lock);
 207         if (val)
 208                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 209         else
 210                 queue_flag_clear(QUEUE_FLAG_SAME_COMP,  q);
 211         spin_unlock_irq(q->queue_lock);
 212 #endif
 213         return ret;
 214 }
 215
 216 static ssize_t queue_iostats_show(struct request_queue *q, char *page)
 217 {
 218         return queue_var_show(blk_queue_io_stat(q), page);
 219 }
 220
 221 static ssize_t queue_iostats_store(struct request_queue *q, const char *page,
 222                                    size_t count)
 223 {
 224         unsigned long stats;
 225         ssize_t ret = queue_var_store(&stats, page, count);
 226
 227         spin_lock_irq(q->queue_lock);
 228         if (stats)
 229                 queue_flag_set(QUEUE_FLAG_IO_STAT, q);
 230         else
 231                 queue_flag_clear(QUEUE_FLAG_IO_STAT, q);
 232         spin_unlock_irq(q->queue_lock);
 233
 234         return ret;
 235 }
 236
 237 static struct queue_sysfs_entry queue_requests_entry = {
 238         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 239         .show = queue_requests_show,
 240         .store = queue_requests_store,
 241 };
 242
 243 static struct queue_sysfs_entry queue_ra_entry = {
 244         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 245         .show = queue_ra_show,
 246         .store = queue_ra_store,
 247 };
 248
 249 static struct queue_sysfs_entry queue_max_sectors_entry = {
 250         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 251         .show = queue_max_sectors_show,
 252         .store = queue_max_sectors_store,
 253 };
 254
 255 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 256         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 257         .show = queue_max_hw_sectors_show,
 258 };
 259
 260 static struct queue_sysfs_entry queue_iosched_entry = {
 261         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 262         .show = elv_iosched_show,
 263         .store = elv_iosched_store,
 264 };
 265
 266 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 267         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 268         .show = queue_logical_block_size_show,
 269 };
 270
 271 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 272         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 273         .show = queue_logical_block_size_show,
 274 };
 275
 276 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 277         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 278         .show = queue_physical_block_size_show,
 279 };
 280
 281 static struct queue_sysfs_entry queue_io_min_entry = {
 282         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 283         .show = queue_io_min_show,
 284 };
 285
 286 static struct queue_sysfs_entry queue_io_opt_entry = {
 287         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 288         .show = queue_io_opt_show,
 289 };
 290
 291 static struct queue_sysfs_entry queue_nonrot_entry = {
 292         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 293         .show = queue_nonrot_show,
 294         .store = queue_nonrot_store,
 295 };
 296
 297 static struct queue_sysfs_entry queue_nomerges_entry = {
 298         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 299         .show = queue_nomerges_show,
 300         .store = queue_nomerges_store,
 301 };
 302
 303 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 304         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 305         .show = queue_rq_affinity_show,
 306         .store = queue_rq_affinity_store,
 307 };
 308
 309 static struct queue_sysfs_entry queue_iostats_entry = {
 310         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 311         .show = queue_iostats_show,
 312         .store = queue_iostats_store,
 313 };
 314
 315 static struct attribute *default_attrs[] = {
 316         &queue_requests_entry.attr,
 317         &queue_ra_entry.attr,
 318         &queue_max_hw_sectors_entry.attr,
 319         &queue_max_sectors_entry.attr,
 320         &queue_iosched_entry.attr,
 321         &queue_hw_sector_size_entry.attr,
 322         &queue_logical_block_size_entry.attr,
 323         &queue_physical_block_size_entry.attr,
 324         &queue_io_min_entry.attr,
 325         &queue_io_opt_entry.attr,
 326         &queue_nonrot_entry.attr,
 327         &queue_nomerges_entry.attr,
 328         &queue_rq_affinity_entry.attr,
 329         &queue_iostats_entry.attr,
 330         NULL,
 331 };
 332
 333 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 334
 335 static ssize_t
 336 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 337 {
 338         struct queue_sysfs_entry *entry = to_queue(attr);
 339         struct request_queue *q =
 340                 container_of(kobj, struct request_queue, kobj);
 341         ssize_t res;
 342
 343         if (!entry->show)
 344                 return -EIO;
 345         mutex_lock(&q->sysfs_lock);
 346         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 347                 mutex_unlock(&q->sysfs_lock);
 348                 return -ENOENT;
 349         }
 350         res = entry->show(q, page);
 351         mutex_unlock(&q->sysfs_lock);
 352         return res;
 353 }
 354
 355 static ssize_t
 356 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 357                     const char *page, size_t length)
 358 {
 359         struct queue_sysfs_entry *entry = to_queue(attr);
 360         struct request_queue *q;
 361         ssize_t res;
 362
 363         if (!entry->store)
 364                 return -EIO;
 365
 366         q = container_of(kobj, struct request_queue, kobj);
 367         mutex_lock(&q->sysfs_lock);
 368         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 369                 mutex_unlock(&q->sysfs_lock);
 370                 return -ENOENT;
 371         }
 372         res = entry->store(q, page, length);
 373         mutex_unlock(&q->sysfs_lock);
 374         return res;
 375 }
 376
 377 /**
 378  * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
 379  * @kobj:    the kobj belonging of the request queue to be released
 380  *
 381  * Description:
 382  *     blk_cleanup_queue is the pair to blk_init_queue() or
 383  *     blk_queue_make_request().  It should be called when a request queue is
 384  *     being released; typically when a block device is being de-registered.
 385  *     Currently, its primary task it to free all the &struct request
 386  *     structures that were allocated to the queue and the queue itself.
 387  *
 388  * Caveat:
 389  *     Hopefully the low level driver will have finished any
 390  *     outstanding requests first...
 391  **/
 392 static void blk_release_queue(struct kobject *kobj)
 393 {
 394         struct request_queue *q =
 395                 container_of(kobj, struct request_queue, kobj);
 396         struct request_list *rl = &q->rq;
 397
 398         blk_sync_queue(q);
 399
 400         if (rl->rq_pool)
 401                 mempool_destroy(rl->rq_pool);
 402
 403         if (q->queue_tags)
 404                 __blk_queue_free_tags(q);
 405
 406         blk_trace_shutdown(q);
 407
 408         bdi_destroy(&q->backing_dev_info);
 409         kmem_cache_free(blk_requestq_cachep, q);
 410 }
 411
 412 static struct sysfs_ops queue_sysfs_ops = {
 413         .show   = queue_attr_show,
 414         .store  = queue_attr_store,
 415 };
 416
 417 struct kobj_type blk_queue_ktype = {
 418         .sysfs_ops      = &queue_sysfs_ops,
 419         .default_attrs  = default_attrs,
 420         .release        = blk_release_queue,
 421 };
 422
 423 int blk_register_queue(struct gendisk *disk)
 424 {
 425         int ret;
 426         struct device *dev = disk_to_dev(disk);
 427
 428         struct request_queue *q = disk->queue;
 429
 430         if (WARN_ON(!q))
 431                 return -ENXIO;
 432
 433         ret = blk_trace_init_sysfs(dev);
 434         if (ret)
 435                 return ret;
 436
 437         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 438         if (ret < 0)
 439                 return ret;
 440
 441         kobject_uevent(&q->kobj, KOBJ_ADD);
 442
 443         if (!q->request_fn)
 444                 return 0;
 445
 446         ret = elv_register_queue(q);
 447         if (ret) {
 448                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 449                 kobject_del(&q->kobj);
 450                 return ret;
 451         }
 452
 453         return 0;
 454 }
 455
 456 void blk_unregister_queue(struct gendisk *disk)
 457 {
 458         struct request_queue *q = disk->queue;
 459
 460         if (WARN_ON(!q))
 461                 return;
 462
 463         if (q->request_fn) {
 464                 elv_unregister_queue(q);
 465
 466                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 467                 kobject_del(&q->kobj);
 468                 kobject_put(&disk_to_dev(disk)->kobj);
 469         }
 470 }