ext4: use swap macro in mext_page_double_lock

Make use of the swap macro and remove unnecessary variable *tmp*. This makes the code easier to read and maintain.

This code was detected with the help of Coccinelle.

---
Changes in v2:
- Update changelog. Remove the line claiming that this patch reduces stack usage.

 fs/ext4/move_extent.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

index 8e17efd..a409ff7 100644
@@ -134,9 +134,7 @@ mext_page_double_lock(struct inode *inode1, struct inode *inode2,
 		mapping[0] = inode1->i_mapping;
 		mapping[1] = inode2->i_mapping;
 	} else {
-		pgoff_t tmp = index1;
-		index1 = index2;
-		index2 = tmp;
+		swap(index1, index2);
 		mapping[0] = inode2->i_mapping;
 		mapping[1] = inode1->i_mapping;
 	}

2.7.4

Thanks, applied.

- Ted