fs: move bdev code out of buffer.c

Move some block device related code out from buffer.c and put it in
block_dev.c. I'm trying to move non-buffer_head code out of buffer.c

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index bd7ac79..f19fd90 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -165,15 +165,8 @@
 void unmap_underlying_metadata(struct block_device *bdev, sector_t block);
 
 void mark_buffer_async_write(struct buffer_head *bh);
-void invalidate_bdev(struct block_device *);
-int sync_blockdev(struct block_device *bdev);
 void __wait_on_buffer(struct buffer_head *);
 wait_queue_head_t *bh_waitq_head(struct buffer_head *bh);
-int fsync_bdev(struct block_device *);
-struct super_block *freeze_bdev(struct block_device *);
-int thaw_bdev(struct block_device *, struct super_block *);
-int fsync_super(struct super_block *);
-int fsync_no_super(struct block_device *);
 struct buffer_head *__find_get_block(struct block_device *bdev, sector_t block,
 			unsigned size);
 struct buffer_head *__getblk(struct block_device *bdev, sector_t block,
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 5f74d61..c2c4454 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1874,6 +1874,13 @@
 extern void bd_forget(struct inode *inode);
 extern void bdput(struct block_device *);
 extern struct block_device *open_by_devnum(dev_t, fmode_t);
+extern void invalidate_bdev(struct block_device *);
+extern int sync_blockdev(struct block_device *bdev);
+extern struct super_block *freeze_bdev(struct block_device *);
+extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
+extern int fsync_bdev(struct block_device *);
+extern int fsync_super(struct super_block *);
+extern int fsync_no_super(struct block_device *);
 #else
 static inline void bd_forget(struct inode *inode) {}
 #endif