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_nomerges_show(struct request_queue *q, char *page)
 134 {
 135         return queue_var_show(blk_queue_nomerges(q), page);
 136 }
 137
 138 static ssize_t queue_nomerges_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_set(QUEUE_FLAG_NOMERGES, q);
 147         else
 148                 queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 149
 150         spin_unlock_irq(q->queue_lock);
 151         return ret;
 152 }
 153
 154 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 155 {
 156         unsigned int set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 157
 158         return queue_var_show(set != 0, page);
 159 }
 160
 161 static ssize_t
 162 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 163 {
 164         ssize_t ret = -EINVAL;
 165 #if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
 166         unsigned long val;
 167
 168         ret = queue_var_store(&val, page, count);
 169         spin_lock_irq(q->queue_lock);
 170         if (val)
 171                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 172         else
 173                 queue_flag_clear(QUEUE_FLAG_SAME_COMP,  q);
 174         spin_unlock_irq(q->queue_lock);
 175 #endif
 176         return ret;
 177 }
 178
 179 static struct queue_sysfs_entry queue_requests_entry = {
 180         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 181         .show = queue_requests_show,
 182         .store = queue_requests_store,
 183 };
 184
 185 static struct queue_sysfs_entry queue_ra_entry = {
 186         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 187         .show = queue_ra_show,
 188         .store = queue_ra_store,
 189 };
 190
 191 static struct queue_sysfs_entry queue_max_sectors_entry = {
 192         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 193         .show = queue_max_sectors_show,
 194         .store = queue_max_sectors_store,
 195 };
 196
 197 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 198         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 199         .show = queue_max_hw_sectors_show,
 200 };
 201
 202 static struct queue_sysfs_entry queue_iosched_entry = {
 203         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 204         .show = elv_iosched_show,
 205         .store = elv_iosched_store,
 206 };
 207
 208 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 209         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 210         .show = queue_hw_sector_size_show,
 211 };
 212
 213 static struct queue_sysfs_entry queue_nomerges_entry = {
 214         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 215         .show = queue_nomerges_show,
 216         .store = queue_nomerges_store,
 217 };
 218
 219 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 220         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 221         .show = queue_rq_affinity_show,
 222         .store = queue_rq_affinity_store,
 223 };
 224
 225 static struct attribute *default_attrs[] = {
 226         &queue_requests_entry.attr,
 227         &queue_ra_entry.attr,
 228         &queue_max_hw_sectors_entry.attr,
 229         &queue_max_sectors_entry.attr,
 230         &queue_iosched_entry.attr,
 231         &queue_hw_sector_size_entry.attr,
 232         &queue_nomerges_entry.attr,
 233         &queue_rq_affinity_entry.attr,
 234         NULL,
 235 };
 236
 237 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 238
 239 static ssize_t
 240 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 241 {
 242         struct queue_sysfs_entry *entry = to_queue(attr);
 243         struct request_queue *q =
 244                 container_of(kobj, struct request_queue, kobj);
 245         ssize_t res;
 246
 247         if (!entry->show)
 248                 return -EIO;
 249         mutex_lock(&q->sysfs_lock);
 250         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 251                 mutex_unlock(&q->sysfs_lock);
 252                 return -ENOENT;
 253         }
 254         res = entry->show(q, page);
 255         mutex_unlock(&q->sysfs_lock);
 256         return res;
 257 }
 258
 259 static ssize_t
 260 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 261                     const char *page, size_t length)
 262 {
 263         struct queue_sysfs_entry *entry = to_queue(attr);
 264         struct request_queue *q;
 265         ssize_t res;
 266
 267         if (!entry->store)
 268                 return -EIO;
 269
 270         q = container_of(kobj, struct request_queue, kobj);
 271         mutex_lock(&q->sysfs_lock);
 272         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 273                 mutex_unlock(&q->sysfs_lock);
 274                 return -ENOENT;
 275         }
 276         res = entry->store(q, page, length);
 277         mutex_unlock(&q->sysfs_lock);
 278         return res;
 279 }
 280
 281 /**
 282  * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
 283  * @kobj:    the kobj belonging of the request queue to be released
 284  *
 285  * Description:
 286  *     blk_cleanup_queue is the pair to blk_init_queue() or
 287  *     blk_queue_make_request().  It should be called when a request queue is
 288  *     being released; typically when a block device is being de-registered.
 289  *     Currently, its primary task it to free all the &struct request
 290  *     structures that were allocated to the queue and the queue itself.
 291  *
 292  * Caveat:
 293  *     Hopefully the low level driver will have finished any
 294  *     outstanding requests first...
 295  **/
 296 static void blk_release_queue(struct kobject *kobj)
 297 {
 298         struct request_queue *q =
 299                 container_of(kobj, struct request_queue, kobj);
 300         struct request_list *rl = &q->rq;
 301
 302         blk_sync_queue(q);
 303
 304         if (rl->rq_pool)
 305                 mempool_destroy(rl->rq_pool);
 306
 307         if (q->queue_tags)
 308                 __blk_queue_free_tags(q);
 309
 310         blk_trace_shutdown(q);
 311
 312         bdi_destroy(&q->backing_dev_info);
 313         kmem_cache_free(blk_requestq_cachep, q);
 314 }
 315
 316 static struct sysfs_ops queue_sysfs_ops = {
 317         .show   = queue_attr_show,
 318         .store  = queue_attr_store,
 319 };
 320
 321 struct kobj_type blk_queue_ktype = {
 322         .sysfs_ops      = &queue_sysfs_ops,
 323         .default_attrs  = default_attrs,
 324         .release        = blk_release_queue,
 325 };
 326
 327 int blk_register_queue(struct gendisk *disk)
 328 {
 329         int ret;
 330
 331         struct request_queue *q = disk->queue;
 332
 333         if (WARN_ON(!q))
 334                 return -ENXIO;
 335
 336         if (!q->request_fn)
 337                 return 0;
 338
 339         ret = kobject_add(&q->kobj, kobject_get(&disk_to_dev(disk)->kobj),
 340                           "%s", "queue");
 341         if (ret < 0)
 342                 return ret;
 343
 344         kobject_uevent(&q->kobj, KOBJ_ADD);
 345
 346         ret = elv_register_queue(q);
 347         if (ret) {
 348                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 349                 kobject_del(&q->kobj);
 350                 return ret;
 351         }
 352
 353         return 0;
 354 }
 355
 356 void blk_unregister_queue(struct gendisk *disk)
 357 {
 358         struct request_queue *q = disk->queue;
 359
 360         if (WARN_ON(!q))
 361                 return;
 362
 363         if (q->request_fn) {
 364                 elv_unregister_queue(q);
 365
 366                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 367                 kobject_del(&q->kobj);
 368                 kobject_put(&disk_to_dev(disk)->kobj);
 369         }
 370 }