mm: bdi init hooks

provide BDI constructor/destructor hooks

[akpm@linux-foundation.org: compile fix]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index c4ef945..d9262f7 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -37,6 +37,11 @@
 	.setattr	= sysfs_setattr,
 };
 
+int __init sysfs_inode_init(void)
+{
+	return bdi_init(&sysfs_backing_dev_info);
+}
+
 int sysfs_setattr(struct dentry * dentry, struct iattr * iattr)
 {
 	struct inode * inode = dentry->d_inode;