drbd: use RB_DECLARE_CALLBACKS() to define augment callbacks

The original code are the same as RB_DECLARE_CALLBACKS().

CC: Michel Lespinasse <walken@google.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

drivers/block/drbd/drbd_interval.c

@@ -37,40 +37,8 @@ compute_subtree_last(struct drbd_interval *node)
 	return max;
 }
 
-static void augment_propagate(struct rb_node *rb, struct rb_node *stop)
-{
-	while (rb != stop) {
-		struct drbd_interval *node = rb_entry(rb, struct drbd_interval, rb);
-		sector_t subtree_last = compute_subtree_last(node);
-		if (node->end == subtree_last)
-			break;
-		node->end = subtree_last;
-		rb = rb_parent(&node->rb);
-	}
-}
-
-static void augment_copy(struct rb_node *rb_old, struct rb_node *rb_new)
-{
-	struct drbd_interval *old = rb_entry(rb_old, struct drbd_interval, rb);
-	struct drbd_interval *new = rb_entry(rb_new, struct drbd_interval, rb);
-
-	new->end = old->end;
-}
-
-static void augment_rotate(struct rb_node *rb_old, struct rb_node *rb_new)
-{
-	struct drbd_interval *old = rb_entry(rb_old, struct drbd_interval, rb);
-	struct drbd_interval *new = rb_entry(rb_new, struct drbd_interval, rb);
-
-	new->end = old->end;
-	old->end = compute_subtree_last(old);
-}
-
-static const struct rb_augment_callbacks augment_callbacks = {
-	augment_propagate,
-	augment_copy,
-	augment_rotate,
-};
+RB_DECLARE_CALLBACKS(static, augment_callbacks, struct drbd_interval, rb,
+		     sector_t, end, compute_subtree_last);
 
 /**
  * drbd_insert_interval  -  insert a new interval into a tree