Btrfs: Make btrfs_dev_extent_chunk_tree_uuid() return unsigned long

Internally, btrfs_dev_extent_chunk_tree_uuid() calculates an unsigned long,
but casts it to a pointer, while all callers cast it to unsigned long
again.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

fs/btrfs/ctree.h

@@ -2330,10 +2330,10 @@ BTRFS_SETGET_FUNCS(dev_extent_chunk_offset, struct btrfs_dev_extent,
 		   chunk_offset, 64);
 BTRFS_SETGET_FUNCS(dev_extent_length, struct btrfs_dev_extent, length, 64);
 
-static inline u8 *btrfs_dev_extent_chunk_tree_uuid(struct btrfs_dev_extent *dev)
+static inline unsigned long btrfs_dev_extent_chunk_tree_uuid(struct btrfs_dev_extent *dev)
 {
 	unsigned long ptr = offsetof(struct btrfs_dev_extent, chunk_tree_uuid);
-	return (u8 *)((unsigned long)dev + ptr);
+	return (unsigned long)dev + ptr;
 }
 
 BTRFS_SETGET_FUNCS(extent_refs, struct btrfs_extent_item, refs, 64);

fs/btrfs/volumes.c

@@ -1311,8 +1311,7 @@ static int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
 	btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
 
 	write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
-		    (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
-		    BTRFS_UUID_SIZE);
+		    btrfs_dev_extent_chunk_tree_uuid(extent), BTRFS_UUID_SIZE);
 
 	btrfs_set_dev_extent_length(leaf, extent, num_bytes);
 	btrfs_mark_buffer_dirty(leaf);