* pseudo-fs
*/
-static struct super_block *bd_get_sb(struct file_system_type *fs_type,
- int flags, const char *dev_name, void *data)
-{
- return get_sb_pseudo(fs_type, "bdev:", NULL, 0x62646576);
-}
+static spinlock_t bdev_lock __cacheline_aligned_in_smp = SPIN_LOCK_UNLOCKED;
+static kmem_cache_t * bdev_cachep;
-static struct file_system_type bd_type = {
- .name = "bdev",
- .get_sb = bd_get_sb,
- .kill_sb = kill_anon_super,
+struct bdev_inode {
+ struct block_device bdev;
+ struct inode vfs_inode;
};
-static struct vfsmount *bd_mnt;
-struct super_block *blockdev_superblock;
-
-/*
- * bdev cache handling - shamelessly stolen from inode.c
- * We use smaller hashtable, though.
- */
+static inline struct bdev_inode *BDEV_I(struct inode *inode)
+{
+ return container_of(inode, struct bdev_inode, vfs_inode);
+}
-#define HASH_BITS 6
-#define HASH_SIZE (1UL << HASH_BITS)
-#define HASH_MASK (HASH_SIZE-1)
-static struct list_head bdev_hashtable[HASH_SIZE];
-static spinlock_t bdev_lock __cacheline_aligned_in_smp = SPIN_LOCK_UNLOCKED;
-static kmem_cache_t * bdev_cachep;
+static struct inode *bdev_alloc_inode(struct super_block *sb)
+{
+ struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, SLAB_KERNEL);
+ if (!ei)
+ return NULL;
+ return &ei->vfs_inode;
+}
-#define alloc_bdev() \
- ((struct block_device *) kmem_cache_alloc(bdev_cachep, SLAB_KERNEL))
-#define destroy_bdev(bdev) kmem_cache_free(bdev_cachep, (bdev))
+static void bdev_destroy_inode(struct inode *inode)
+{
+ kmem_cache_free(bdev_cachep, BDEV_I(inode));
+}
static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
{
- struct block_device * bdev = (struct block_device *) foo;
+ struct bdev_inode *ei = (struct bdev_inode *) foo;
+ struct block_device *bdev = &ei->bdev;
if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
SLAB_CTOR_CONSTRUCTOR)
memset(bdev, 0, sizeof(*bdev));
sema_init(&bdev->bd_sem, 1);
INIT_LIST_HEAD(&bdev->bd_inodes);
+ INIT_LIST_HEAD(&bdev->bd_list);
+ inode_init_once(&ei->vfs_inode);
}
}
-void __init bdev_cache_init(void)
+static inline void __bd_forget(struct inode *inode)
+{
+ list_del_init(&inode->i_devices);
+ inode->i_bdev = NULL;
+ inode->i_mapping = &inode->i_data;
+}
+
+static void bdev_clear_inode(struct inode *inode)
+{
+ struct block_device *bdev = &BDEV_I(inode)->bdev;
+ struct list_head *p;
+ spin_lock(&bdev_lock);
+ while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) {
+ __bd_forget(list_entry(p, struct inode, i_devices));
+ }
+ list_del_init(&bdev->bd_list);
+ spin_unlock(&bdev_lock);
+}
+
+static struct super_operations bdev_sops = {
+ .statfs = simple_statfs,
+ .alloc_inode = bdev_alloc_inode,
+ .destroy_inode = bdev_destroy_inode,
+ .drop_inode = generic_delete_inode,
+ .clear_inode = bdev_clear_inode,
+};
+
+static struct super_block *bd_get_sb(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *data)
{
- int i, err;
- struct list_head *head = bdev_hashtable;
+ return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576);
+}
- i = HASH_SIZE;
- do {
- INIT_LIST_HEAD(head);
- head++;
- i--;
- } while (i);
+static struct file_system_type bd_type = {
+ .name = "bdev",
+ .get_sb = bd_get_sb,
+ .kill_sb = kill_anon_super,
+};
+static struct vfsmount *bd_mnt;
+struct super_block *blockdev_superblock;
+
+void __init bdev_cache_init(void)
+{
+ int err;
bdev_cachep = kmem_cache_create("bdev_cache",
- sizeof(struct block_device),
- 0, SLAB_HWCACHE_ALIGN, init_once,
- NULL);
+ sizeof(struct bdev_inode),
+ 0,
+ SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT,
+ init_once,
+ NULL);
if (!bdev_cachep)
panic("Cannot create bdev_cache SLAB cache");
err = register_filesystem(&bd_type);
/*
* Most likely _very_ bad one - but then it's hardly critical for small
* /dev and can be fixed when somebody will need really large one.
+ * Keep in mind that it will be fed through icache hash function too.
*/
static inline unsigned long hash(dev_t dev)
{
- unsigned long tmp = dev;
- tmp = tmp + (tmp >> HASH_BITS) + (tmp >> HASH_BITS*2);
- return tmp & HASH_MASK;
+ return MAJOR(dev)+MINOR(dev);
}
-static struct block_device *bdfind(dev_t dev, struct list_head *head)
+static int bdev_test(struct inode *inode, void *data)
{
- struct list_head *p;
- struct block_device *bdev;
- list_for_each(p, head) {
- bdev = list_entry(p, struct block_device, bd_hash);
- if (bdev->bd_dev != dev)
- continue;
- atomic_inc(&bdev->bd_count);
- return bdev;
- }
- return NULL;
+ return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data;
+}
+
+static int bdev_set(struct inode *inode, void *data)
+{
+ BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data;
+ return 0;
}
+static LIST_HEAD(all_bdevs);
+
struct block_device *bdget(dev_t dev)
{
- struct list_head * head = bdev_hashtable + hash(dev);
- struct block_device *bdev, *new_bdev;
- spin_lock(&bdev_lock);
- bdev = bdfind(dev, head);
- spin_unlock(&bdev_lock);
- if (bdev)
- return bdev;
- new_bdev = alloc_bdev();
- if (new_bdev) {
- struct inode *inode = new_inode(bd_mnt->mnt_sb);
- if (inode) {
- kdev_t kdev = to_kdev_t(dev);
-
- atomic_set(&new_bdev->bd_count,1);
- new_bdev->bd_dev = dev;
- new_bdev->bd_contains = NULL;
- new_bdev->bd_inode = inode;
- new_bdev->bd_block_size = (1 << inode->i_blkbits);
- new_bdev->bd_part_count = 0;
- new_bdev->bd_invalidated = 0;
- inode->i_mode = S_IFBLK;
- inode->i_rdev = kdev;
- inode->i_bdev = new_bdev;
- inode->i_data.a_ops = &def_blk_aops;
- mapping_set_gfp_mask(&inode->i_data, GFP_USER);
- inode->i_data.backing_dev_info = &default_backing_dev_info;
- spin_lock(&bdev_lock);
- bdev = bdfind(dev, head);
- if (!bdev) {
- list_add(&new_bdev->bd_hash, head);
- spin_unlock(&bdev_lock);
- return new_bdev;
- }
- spin_unlock(&bdev_lock);
- iput(new_bdev->bd_inode);
- }
- destroy_bdev(new_bdev);
+ struct block_device *bdev;
+ struct inode *inode;
+
+ inode = iget5_locked(bd_mnt->mnt_sb, hash(dev),
+ bdev_test, bdev_set, &dev);
+
+ if (!inode)
+ return NULL;
+
+ bdev = &BDEV_I(inode)->bdev;
+
+ if (inode->i_state & I_NEW) {
+ bdev->bd_contains = NULL;
+ bdev->bd_inode = inode;
+ bdev->bd_block_size = (1 << inode->i_blkbits);
+ bdev->bd_part_count = 0;
+ bdev->bd_invalidated = 0;
+ inode->i_mode = S_IFBLK;
+ inode->i_rdev = to_kdev_t(dev);
+ inode->i_bdev = bdev;
+ inode->i_data.a_ops = &def_blk_aops;
+ mapping_set_gfp_mask(&inode->i_data, GFP_USER);
+ inode->i_data.backing_dev_info = &default_backing_dev_info;
+ spin_lock(&bdev_lock);
+ list_add(&bdev->bd_list, &all_bdevs);
+ spin_unlock(&bdev_lock);
+ unlock_new_inode(inode);
}
return bdev;
}
long nr_blockdev_pages(void)
{
+ struct list_head *p;
long ret = 0;
- int i;
-
spin_lock(&bdev_lock);
- for (i = 0; i < ARRAY_SIZE(bdev_hashtable); i++) {
- struct list_head *head = &bdev_hashtable[i];
- struct list_head *lh;
-
- if (head == NULL)
- continue;
- list_for_each(lh, head) {
- struct block_device *bdev;
-
- bdev = list_entry(lh, struct block_device, bd_hash);
- ret += bdev->bd_inode->i_mapping->nrpages;
- }
+ list_for_each(p, &all_bdevs) {
+ struct block_device *bdev;
+ bdev = list_entry(p, struct block_device, bd_list);
+ ret += bdev->bd_inode->i_mapping->nrpages;
}
spin_unlock(&bdev_lock);
return ret;
}
-static inline void __bd_forget(struct inode *inode)
-{
- list_del_init(&inode->i_devices);
- inode->i_bdev = NULL;
- inode->i_mapping = &inode->i_data;
-}
-
void bdput(struct block_device *bdev)
{
- if (atomic_dec_and_lock(&bdev->bd_count, &bdev_lock)) {
- struct list_head *p;
- if (bdev->bd_openers)
- BUG();
- list_del(&bdev->bd_hash);
- while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) {
- __bd_forget(list_entry(p, struct inode, i_devices));
- }
- spin_unlock(&bdev_lock);
- iput(bdev->bd_inode);
- destroy_bdev(bdev);
- }
+ iput(bdev->bd_inode);
}
int bd_acquire(struct inode *inode)
{
struct block_device *bdev;
spin_lock(&bdev_lock);
- if (inode->i_bdev) {
- atomic_inc(&inode->i_bdev->bd_count);
+ if (inode->i_bdev && igrab(inode->i_bdev->bd_inode)) {
spin_unlock(&bdev_lock);
return 0;
}
if (!bdev)
return -ENOMEM;
spin_lock(&bdev_lock);
- if (!inode->i_bdev) {
- inode->i_bdev = bdev;
- inode->i_mapping = bdev->bd_inode->i_mapping;
- list_add(&inode->i_devices, &bdev->bd_inodes);
- } else if (inode->i_bdev != bdev)
- BUG();
+ if (inode->i_bdev)
+ __bd_forget(inode);
+ inode->i_bdev = bdev;
+ inode->i_mapping = bdev->bd_inode->i_mapping;
+ list_add(&inode->i_devices, &bdev->bd_inodes);
spin_unlock(&bdev_lock);
return 0;
}
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