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 int var, char *page)
  20 {
  21         return sprintf(page, "%d\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[READ] >= queue_congestion_on_threshold(q))
  52                 blk_set_queue_congested(q, READ);
  53         else if (rl->count[READ] < queue_congestion_off_threshold(q))
  54                 blk_clear_queue_congested(q, READ);
  55
  56         if (rl->count[WRITE] >= queue_congestion_on_threshold(q))
  57                 blk_set_queue_congested(q, WRITE);
  58         else if (rl->count[WRITE] < queue_congestion_off_threshold(q))
  59                 blk_clear_queue_congested(q, WRITE);
  60
  61         if (rl->count[READ] >= q->nr_requests) {
  62                 blk_set_queue_full(q, READ);
  63         } else if (rl->count[READ]+1 <= q->nr_requests) {
  64                 blk_clear_queue_full(q, READ);
  65                 wake_up(&rl->wait[READ]);
  66         }
  67
  68         if (rl->count[WRITE] >= q->nr_requests) {
  69                 blk_set_queue_full(q, WRITE);
  70         } else if (rl->count[WRITE]+1 <= q->nr_requests) {
  71                 blk_clear_queue_full(q, WRITE);
  72                 wake_up(&rl->wait[WRITE]);
  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         int ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10);
  81
  82         return queue_var_show(ra_kb, (page));
  83 }
  84
  85 static ssize_t
  86 queue_ra_store(struct request_queue *q, const char *page, size_t count)
  87 {
  88         unsigned long ra_kb;
  89         ssize_t ret = queue_var_store(&ra_kb, page, count);
  90
  91         q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
  92
  93         return ret;
  94 }
  95
  96 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
  97 {
  98         int max_sectors_kb = q->max_sectors >> 1;
  99
 100         return queue_var_show(max_sectors_kb, (page));
 101 }
 102
 103 static ssize_t queue_hw_sector_size_show(struct request_queue *q, char *page)
 104 {
 105         return queue_var_show(q->hardsect_size, page);
 106 }
 107
 108 static ssize_t
 109 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 110 {
 111         unsigned long max_sectors_kb,
 112                         max_hw_sectors_kb = q->max_hw_sectors >> 1,
 113                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
 114         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 115
 116         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 117                 return -EINVAL;
 118
 119         spin_lock_irq(q->queue_lock);
 120         q->max_sectors = max_sectors_kb << 1;
 121         spin_unlock_irq(q->queue_lock);
 122
 123         return ret;
 124 }
 125
 126 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 127 {
 128         int max_hw_sectors_kb = q->max_hw_sectors >> 1;
 129
 130         return queue_var_show(max_hw_sectors_kb, (page));
 131 }
 132
 133 static ssize_t queue_nonrot_show(struct request_queue *q, char *page)
 134 {
 135         return queue_var_show(!blk_queue_nonrot(q), page);
 136 }
 137
 138 static ssize_t queue_nonrot_store(struct request_queue *q, const char *page,
 139                                   size_t count)
 140 {
 141         unsigned long nm;
 142         ssize_t ret = queue_var_store(&nm, page, count);
 143
 144         spin_lock_irq(q->queue_lock);
 145         if (nm)
 146                 queue_flag_clear(QUEUE_FLAG_NONROT, q);
 147         else
 148                 queue_flag_set(QUEUE_FLAG_NONROT, q);
 149         spin_unlock_irq(q->queue_lock);
 150
 151         return ret;
 152 }
 153
 154 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 155 {
 156         return queue_var_show(blk_queue_nomerges(q), page);
 157 }
 158
 159 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 160                                     size_t count)
 161 {
 162         unsigned long nm;
 163         ssize_t ret = queue_var_store(&nm, page, count);
 164
 165         spin_lock_irq(q->queue_lock);
 166         if (nm)
 167                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 168         else
 169                 queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 170         spin_unlock_irq(q->queue_lock);
 171
 172         return ret;
 173 }
 174
 175 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 176 {
 177         unsigned int set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 178
 179         return queue_var_show(set != 0, page);
 180 }
 181
 182 static ssize_t
 183 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 184 {
 185         ssize_t ret = -EINVAL;
 186 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
 187         unsigned long val;
 188
 189         ret = queue_var_store(&val, page, count);
 190         spin_lock_irq(q->queue_lock);
 191         if (val)
 192                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 193         else
 194                 queue_flag_clear(QUEUE_FLAG_SAME_COMP,  q);
 195         spin_unlock_irq(q->queue_lock);
 196 #endif
 197         return ret;
 198 }
 199
 200 static ssize_t queue_iostats_show(struct request_queue *q, char *page)
 201 {
 202         return queue_var_show(blk_queue_io_stat(q), page);
 203 }
 204
 205 static ssize_t queue_iostats_store(struct request_queue *q, const char *page,
 206                                    size_t count)
 207 {
 208         unsigned long stats;
 209         ssize_t ret = queue_var_store(&stats, page, count);
 210
 211         spin_lock_irq(q->queue_lock);
 212         if (stats)
 213                 queue_flag_set(QUEUE_FLAG_IO_STAT, q);
 214         else
 215                 queue_flag_clear(QUEUE_FLAG_IO_STAT, q);
 216         spin_unlock_irq(q->queue_lock);
 217
 218         return ret;
 219 }
 220
 221 static struct queue_sysfs_entry queue_requests_entry = {
 222         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 223         .show = queue_requests_show,
 224         .store = queue_requests_store,
 225 };
 226
 227 static struct queue_sysfs_entry queue_ra_entry = {
 228         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 229         .show = queue_ra_show,
 230         .store = queue_ra_store,
 231 };
 232
 233 static struct queue_sysfs_entry queue_max_sectors_entry = {
 234         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 235         .show = queue_max_sectors_show,
 236         .store = queue_max_sectors_store,
 237 };
 238
 239 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 240         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 241         .show = queue_max_hw_sectors_show,
 242 };
 243
 244 static struct queue_sysfs_entry queue_iosched_entry = {
 245         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 246         .show = elv_iosched_show,
 247         .store = elv_iosched_store,
 248 };
 249
 250 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 251         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 252         .show = queue_hw_sector_size_show,
 253 };
 254
 255 static struct queue_sysfs_entry queue_nonrot_entry = {
 256         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 257         .show = queue_nonrot_show,
 258         .store = queue_nonrot_store,
 259 };
 260
 261 static struct queue_sysfs_entry queue_nomerges_entry = {
 262         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 263         .show = queue_nomerges_show,
 264         .store = queue_nomerges_store,
 265 };
 266
 267 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 268         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 269         .show = queue_rq_affinity_show,
 270         .store = queue_rq_affinity_store,
 271 };
 272
 273 static struct queue_sysfs_entry queue_iostats_entry = {
 274         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 275         .show = queue_iostats_show,
 276         .store = queue_iostats_store,
 277 };
 278
 279 static struct attribute *default_attrs[] = {
 280         &queue_requests_entry.attr,
 281         &queue_ra_entry.attr,
 282         &queue_max_hw_sectors_entry.attr,
 283         &queue_max_sectors_entry.attr,
 284         &queue_iosched_entry.attr,
 285         &queue_hw_sector_size_entry.attr,
 286         &queue_nonrot_entry.attr,
 287         &queue_nomerges_entry.attr,
 288         &queue_rq_affinity_entry.attr,
 289         &queue_iostats_entry.attr,
 290         NULL,
 291 };
 292
 293 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 294
 295 static ssize_t
 296 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 297 {
 298         struct queue_sysfs_entry *entry = to_queue(attr);
 299         struct request_queue *q =
 300                 container_of(kobj, struct request_queue, kobj);
 301         ssize_t res;
 302
 303         if (!entry->show)
 304                 return -EIO;
 305         mutex_lock(&q->sysfs_lock);
 306         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 307                 mutex_unlock(&q->sysfs_lock);
 308                 return -ENOENT;
 309         }
 310         res = entry->show(q, page);
 311         mutex_unlock(&q->sysfs_lock);
 312         return res;
 313 }
 314
 315 static ssize_t
 316 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 317                     const char *page, size_t length)
 318 {
 319         struct queue_sysfs_entry *entry = to_queue(attr);
 320         struct request_queue *q;
 321         ssize_t res;
 322
 323         if (!entry->store)
 324                 return -EIO;
 325
 326         q = container_of(kobj, struct request_queue, kobj);
 327         mutex_lock(&q->sysfs_lock);
 328         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 329                 mutex_unlock(&q->sysfs_lock);
 330                 return -ENOENT;
 331         }
 332         res = entry->store(q, page, length);
 333         mutex_unlock(&q->sysfs_lock);
 334         return res;
 335 }
 336
 337 /**
 338  * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
 339  * @kobj:    the kobj belonging of the request queue to be released
 340  *
 341  * Description:
 342  *     blk_cleanup_queue is the pair to blk_init_queue() or
 343  *     blk_queue_make_request().  It should be called when a request queue is
 344  *     being released; typically when a block device is being de-registered.
 345  *     Currently, its primary task it to free all the &struct request
 346  *     structures that were allocated to the queue and the queue itself.
 347  *
 348  * Caveat:
 349  *     Hopefully the low level driver will have finished any
 350  *     outstanding requests first...
 351  **/
 352 static void blk_release_queue(struct kobject *kobj)
 353 {
 354         struct request_queue *q =
 355                 container_of(kobj, struct request_queue, kobj);
 356         struct request_list *rl = &q->rq;
 357
 358         blk_sync_queue(q);
 359
 360         if (rl->rq_pool)
 361                 mempool_destroy(rl->rq_pool);
 362
 363         if (q->queue_tags)
 364                 __blk_queue_free_tags(q);
 365
 366         blk_trace_shutdown(q);
 367
 368         bdi_destroy(&q->backing_dev_info);
 369         kmem_cache_free(blk_requestq_cachep, q);
 370 }
 371
 372 static struct sysfs_ops queue_sysfs_ops = {
 373         .show   = queue_attr_show,
 374         .store  = queue_attr_store,
 375 };
 376
 377 struct kobj_type blk_queue_ktype = {
 378         .sysfs_ops      = &queue_sysfs_ops,
 379         .default_attrs  = default_attrs,
 380         .release        = blk_release_queue,
 381 };
 382
 383 int blk_register_queue(struct gendisk *disk)
 384 {
 385         int ret;
 386
 387         struct request_queue *q = disk->queue;
 388
 389         if (WARN_ON(!q))
 390                 return -ENXIO;
 391
 392         if (!q->request_fn)
 393                 return 0;
 394
 395         ret = kobject_add(&q->kobj, kobject_get(&disk_to_dev(disk)->kobj),
 396                           "%s", "queue");
 397         if (ret < 0)
 398                 return ret;
 399
 400         kobject_uevent(&q->kobj, KOBJ_ADD);
 401
 402         ret = elv_register_queue(q);
 403         if (ret) {
 404                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 405                 kobject_del(&q->kobj);
 406                 return ret;
 407         }
 408
 409         return 0;
 410 }
 411
 412 void blk_unregister_queue(struct gendisk *disk)
 413 {
 414         struct request_queue *q = disk->queue;
 415
 416         if (WARN_ON(!q))
 417                 return;
 418
 419         if (q->request_fn) {
 420                 elv_unregister_queue(q);
 421
 422                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 423                 kobject_del(&q->kobj);
 424                 kobject_put(&disk_to_dev(disk)->kobj);
 425         }
 426 }