rbtree, timerqueue: Use rb_add_cached()

Reduce rbtree boiler plate by using the new helpers.

Signed-off-by: Peter Zijlstra (Intel) <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>
Acked-by: Davidlohr Bueso <[e-mail]>

lib/timerqueue.c

···
 #include <linux/rbtree.h>
 #include <linux/export.h>
 
+#define __node_2_tq(_n) \
+	rb_entry((_n), struct timerqueue_node, node)
+
+static inline bool __timerqueue_less(struct rb_node *a, const struct rb_node *b)
+{
+	return __node_2_tq(a)->expires < __node_2_tq(b)->expires;
+}
+
 /**
  * timerqueue_add - Adds timer to timerqueue.
  *
···
  */
 bool timerqueue_add(struct timerqueue_head *head, struct timerqueue_node *node)
 {
-	struct rb_node **p = &head->rb_root.rb_root.rb_node;
-	struct rb_node *parent = NULL;
-	struct timerqueue_node *ptr;
-	bool leftmost = true;
-
 	/* Make sure we don't add nodes that are already added */
 	WARN_ON_ONCE(!RB_EMPTY_NODE(&node->node));
 
-	while (*p) {
-		parent = *p;
-		ptr = rb_entry(parent, struct timerqueue_node, node);
-		if (node->expires < ptr->expires) {
-			p = &(*p)->rb_left;
-		} else {
-			p = &(*p)->rb_right;
-			leftmost = false;
-		}
-	}
-	rb_link_node(&node->node, parent, p);
-	rb_insert_color_cached(&node->node, &head->rb_root, leftmost);
-
-	return leftmost;
+	return rb_add_cached(&node->node, &head->rb_root, __timerqueue_less);
 }
 EXPORT_SYMBOL_GPL(timerqueue_add);