[PATCH/RFCv4 1/6] lib: rbtree: rb_root_init() function added

Michal Nazarewicz
2010-08-20T09:50:41Z

Added a rb_root_init() function which initialises a rb_root
structure as a red-black tree with at most one element. The
rationale is that using rb_root_init(root, node) is more
straightforward and cleaner then first initialising and
empty tree followed by an insert operation.

Signed-off-by: Michal Nazarewicz <m.nazarewicz@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
include/linux/rbtree.h | 11 +++++++++++
1 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h
index 7066acb..5b6dc66 100644
--- a/include/linux/rbtree.h
+++ b/include/linux/rbtree.h
@@ -130,6 +130,17 @@ static inline void rb_set_color(struct rb_node *rb, int color)
}

#define RB_ROOT (struct rb_root) { NULL, }
+
+static inline void rb_root_init(struct rb_root *root, struct rb_node *node)
+{
+ root->rb_node = node;
+ if (node) {
+ node->rb_parent_color = RB_BLACK; /* black, no parent */
+ node->rb_left = NULL;
+ node->rb_right = NULL;
+ }
+}
+
#define rb_entry(ptr, type, member) container_of(ptr, type, member)

#define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL)
--
1.7.1