SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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
 106 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 107 {
 108         unsigned long max_sectors_kb,
 109                         max_hw_sectors_kb = q->max_hw_sectors >> 1,
 110                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
 111         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 112
 113         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 114                 return -EINVAL;
 115         /*
 116          * Take the queue lock to update the readahead and max_sectors
 117          * values synchronously:
 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
 134 static struct queue_sysfs_entry queue_requests_entry = {
 135         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 136         .show = queue_requests_show,
 137         .store = queue_requests_store,
 138 };
 139
 140 static struct queue_sysfs_entry queue_ra_entry = {
 141         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 142         .show = queue_ra_show,
 143         .store = queue_ra_store,
 144 };
 145
 146 static struct queue_sysfs_entry queue_max_sectors_entry = {
 147         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 148         .show = queue_max_sectors_show,
 149         .store = queue_max_sectors_store,
 150 };
 151
 152 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 153         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 154         .show = queue_max_hw_sectors_show,
 155 };
 156
 157 static struct queue_sysfs_entry queue_iosched_entry = {
 158         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 159         .show = elv_iosched_show,
 160         .store = elv_iosched_store,
 161 };
 162
 163 static struct attribute *default_attrs[] = {
 164         &queue_requests_entry.attr,
 165         &queue_ra_entry.attr,
 166         &queue_max_hw_sectors_entry.attr,
 167         &queue_max_sectors_entry.attr,
 168         &queue_iosched_entry.attr,
 169         NULL,
 170 };
 171
 172 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 173
 174 static ssize_t
 175 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 176 {
 177         struct queue_sysfs_entry *entry = to_queue(attr);
 178         struct request_queue *q =
 179                 container_of(kobj, struct request_queue, kobj);
 180         ssize_t res;
 181
 182         if (!entry->show)
 183                 return -EIO;
 184         mutex_lock(&q->sysfs_lock);
 185         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 186                 mutex_unlock(&q->sysfs_lock);
 187                 return -ENOENT;
 188         }
 189         res = entry->show(q, page);
 190         mutex_unlock(&q->sysfs_lock);
 191         return res;
 192 }
 193
 194 static ssize_t
 195 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 196                     const char *page, size_t length)
 197 {
 198         struct queue_sysfs_entry *entry = to_queue(attr);
 199         struct request_queue *q = container_of(kobj, struct request_queue, kobj);
 200
 201         ssize_t res;
 202
 203         if (!entry->store)
 204                 return -EIO;
 205         mutex_lock(&q->sysfs_lock);
 206         if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 207                 mutex_unlock(&q->sysfs_lock);
 208                 return -ENOENT;
 209         }
 210         res = entry->store(q, page, length);
 211         mutex_unlock(&q->sysfs_lock);
 212         return res;
 213 }
 214
 215 /**
 216  * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
 217  * @kobj:    the kobj belonging of the request queue to be released
 218  *
 219  * Description:
 220  *     blk_cleanup_queue is the pair to blk_init_queue() or
 221  *     blk_queue_make_request().  It should be called when a request queue is
 222  *     being released; typically when a block device is being de-registered.
 223  *     Currently, its primary task it to free all the &struct request
 224  *     structures that were allocated to the queue and the queue itself.
 225  *
 226  * Caveat:
 227  *     Hopefully the low level driver will have finished any
 228  *     outstanding requests first...
 229  **/
 230 static void blk_release_queue(struct kobject *kobj)
 231 {
 232         struct request_queue *q =
 233                 container_of(kobj, struct request_queue, kobj);
 234         struct request_list *rl = &q->rq;
 235
 236         blk_sync_queue(q);
 237
 238         if (rl->rq_pool)
 239                 mempool_destroy(rl->rq_pool);
 240
 241         if (q->queue_tags)
 242                 __blk_queue_free_tags(q);
 243
 244         blk_trace_shutdown(q);
 245
 246         bdi_destroy(&q->backing_dev_info);
 247         kmem_cache_free(blk_requestq_cachep, q);
 248 }
 249
 250 static struct sysfs_ops queue_sysfs_ops = {
 251         .show   = queue_attr_show,
 252         .store  = queue_attr_store,
 253 };
 254
 255 struct kobj_type blk_queue_ktype = {
 256         .sysfs_ops      = &queue_sysfs_ops,
 257         .default_attrs  = default_attrs,
 258         .release        = blk_release_queue,
 259 };
 260
 261 int blk_register_queue(struct gendisk *disk)
 262 {
 263         int ret;
 264
 265         struct request_queue *q = disk->queue;
 266
 267         if (!q || !q->request_fn)
 268                 return -ENXIO;
 269
 270         ret = kobject_add(&q->kobj, kobject_get(&disk->dev.kobj),
 271                           "%s", "queue");
 272         if (ret < 0)
 273                 return ret;
 274
 275         kobject_uevent(&q->kobj, KOBJ_ADD);
 276
 277         ret = elv_register_queue(q);
 278         if (ret) {
 279                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 280                 kobject_del(&q->kobj);
 281                 return ret;
 282         }
 283
 284         return 0;
 285 }
 286
 287 void blk_unregister_queue(struct gendisk *disk)
 288 {
 289         struct request_queue *q = disk->queue;
 290
 291         if (q && q->request_fn) {
 292                 elv_unregister_queue(q);
 293
 294                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 295                 kobject_del(&q->kobj);
 296                 kobject_put(&disk->dev.kobj);
 297         }
 298 }