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 struct queue_sysfs_entry queue_requests_entry = {
 201         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 202         .show = queue_requests_show,
 203         .store = queue_requests_store,
 204 };
 205
 206 static struct queue_sysfs_entry queue_ra_entry = {
 207         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 208         .show = queue_ra_show,
 209         .store = queue_ra_store,
 210 };
 211
 212 static struct queue_sysfs_entry queue_max_sectors_entry = {
 213         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 214         .show = queue_max_sectors_show,
 215         .store = queue_max_sectors_store,
 216 };
 217
 218 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 219         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 220         .show = queue_max_hw_sectors_show,
 221 };
 222
 223 static struct queue_sysfs_entry queue_iosched_entry = {
 224         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 225         .show = elv_iosched_show,
 226         .store = elv_iosched_store,
 227 };
 228
 229 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 230         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 231         .show = queue_hw_sector_size_show,
 232 };
 233
 234 static struct queue_sysfs_entry queue_nonrot_entry = {
 235         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 236         .show = queue_nonrot_show,
 237         .store = queue_nonrot_store,
 238 };
 239
 240 static struct queue_sysfs_entry queue_nomerges_entry = {
 241         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 242         .show = queue_nomerges_show,
 243         .store = queue_nomerges_store,
 244 };
 245
 246 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 247         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 248         .show = queue_rq_affinity_show,
 249         .store = queue_rq_affinity_store,
 250 };
 251
 252 static struct attribute *default_attrs[] = {
 253         &queue_requests_entry.attr,
 254         &queue_ra_entry.attr,
 255         &queue_max_hw_sectors_entry.attr,
 256         &queue_max_sectors_entry.attr,
 257         &queue_iosched_entry.attr,
 258         &queue_hw_sector_size_entry.attr,
 259         &queue_nonrot_entry.attr,
 260         &queue_nomerges_entry.attr,
 261         &queue_rq_affinity_entry.attr,
 262         NULL,
 263 };
 264
 265 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 266
 267 static ssize_t
 268 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 269 {
 270         struct queue_sysfs_entry *entry = to_queue(attr);
 271         struct request_queue *q =
 272                 container_of(kobj, struct request_queue, kobj);
 273         ssize_t res;
 274
 275         if (!entry->show)
 276                 return -EIO;
 277         mutex_lock(&q->sysfs_lock);
 278         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 279                 mutex_unlock(&q->sysfs_lock);
 280                 return -ENOENT;
 281         }
 282         res = entry->show(q, page);
 283         mutex_unlock(&q->sysfs_lock);
 284         return res;
 285 }
 286
 287 static ssize_t
 288 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 289                     const char *page, size_t length)
 290 {
 291         struct queue_sysfs_entry *entry = to_queue(attr);
 292         struct request_queue *q;
 293         ssize_t res;
 294
 295         if (!entry->store)
 296                 return -EIO;
 297
 298         q = container_of(kobj, struct request_queue, kobj);
 299         mutex_lock(&q->sysfs_lock);
 300         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 301                 mutex_unlock(&q->sysfs_lock);
 302                 return -ENOENT;
 303         }
 304         res = entry->store(q, page, length);
 305         mutex_unlock(&q->sysfs_lock);
 306         return res;
 307 }
 308
 309 /**
 310  * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
 311  * @kobj:    the kobj belonging of the request queue to be released
 312  *
 313  * Description:
 314  *     blk_cleanup_queue is the pair to blk_init_queue() or
 315  *     blk_queue_make_request().  It should be called when a request queue is
 316  *     being released; typically when a block device is being de-registered.
 317  *     Currently, its primary task it to free all the &struct request
 318  *     structures that were allocated to the queue and the queue itself.
 319  *
 320  * Caveat:
 321  *     Hopefully the low level driver will have finished any
 322  *     outstanding requests first...
 323  **/
 324 static void blk_release_queue(struct kobject *kobj)
 325 {
 326         struct request_queue *q =
 327                 container_of(kobj, struct request_queue, kobj);
 328         struct request_list *rl = &q->rq;
 329
 330         blk_sync_queue(q);
 331
 332         if (rl->rq_pool)
 333                 mempool_destroy(rl->rq_pool);
 334
 335         if (q->queue_tags)
 336                 __blk_queue_free_tags(q);
 337
 338         blk_trace_shutdown(q);
 339
 340         bdi_destroy(&q->backing_dev_info);
 341         kmem_cache_free(blk_requestq_cachep, q);
 342 }
 343
 344 static struct sysfs_ops queue_sysfs_ops = {
 345         .show   = queue_attr_show,
 346         .store  = queue_attr_store,
 347 };
 348
 349 struct kobj_type blk_queue_ktype = {
 350         .sysfs_ops      = &queue_sysfs_ops,
 351         .default_attrs  = default_attrs,
 352         .release        = blk_release_queue,
 353 };
 354
 355 int blk_register_queue(struct gendisk *disk)
 356 {
 357         int ret;
 358
 359         struct request_queue *q = disk->queue;
 360
 361         if (WARN_ON(!q))
 362                 return -ENXIO;
 363
 364         if (!q->request_fn)
 365                 return 0;
 366
 367         ret = kobject_add(&q->kobj, kobject_get(&disk_to_dev(disk)->kobj),
 368                           "%s", "queue");
 369         if (ret < 0)
 370                 return ret;
 371
 372         kobject_uevent(&q->kobj, KOBJ_ADD);
 373
 374         ret = elv_register_queue(q);
 375         if (ret) {
 376                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 377                 kobject_del(&q->kobj);
 378                 return ret;
 379         }
 380
 381         return 0;
 382 }
 383
 384 void blk_unregister_queue(struct gendisk *disk)
 385 {
 386         struct request_queue *q = disk->queue;
 387
 388         if (WARN_ON(!q))
 389                 return;
 390
 391         if (q->request_fn) {
 392                 elv_unregister_queue(q);
 393
 394                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 395                 kobject_del(&q->kobj);
 396                 kobject_put(&disk_to_dev(disk)->kobj);
 397         }
 398 }