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