1 files changed, 120 insertions, 0 deletions
diff --git a/include/linux/prio_tree.h b/include/linux/prio_tree.h
new file mode 100644
index 00000000000..db04abb557e
--- /dev/null
+++ b/include/linux/prio_tree.h
@@ -0,0 +1,120 @@
+#ifndef _LINUX_PRIO_TREE_H
+#define _LINUX_PRIO_TREE_H
+
+/*
+ * K&R 2nd ed. A8.3 somewhat obliquely hints that initial sequences of struct
+ * fields with identical types should end up at the same location. We'll use
+ * this until we can scrap struct raw_prio_tree_node.
+ *
+ * Note: all this could be done more elegantly by using unnamed union/struct
+ * fields. However, gcc 2.95.3 and apparently also gcc 3.0.4 don't support this
+ * language extension.
+ */
+
+struct raw_prio_tree_node {
+	struct prio_tree_node	*left;
+	struct prio_tree_node	*right;
+	struct prio_tree_node	*parent;
+};
+
+struct prio_tree_node {
+	struct prio_tree_node	*left;
+	struct prio_tree_node	*right;
+	struct prio_tree_node	*parent;
+	unsigned long		start;
+	unsigned long		last;	/* last location _in_ interval */
+};
+
+struct prio_tree_root {
+	struct prio_tree_node	*prio_tree_node;
+	unsigned short 		index_bits;
+	unsigned short		raw;
+		/*
+		 * 0: nodes are of type struct prio_tree_node
+		 * 1: nodes are of type raw_prio_tree_node
+		 */
+};
+
+struct prio_tree_iter {
+	struct prio_tree_node	*cur;
+	unsigned long		mask;
+	unsigned long		value;
+	int			size_level;
+
+	struct prio_tree_root	*root;
+	pgoff_t			r_index;
+	pgoff_t			h_index;
+};
+
+static inline void prio_tree_iter_init(struct prio_tree_iter *iter,
+		struct prio_tree_root *root, pgoff_t r_index, pgoff_t h_index)
+{
+	iter->root = root;
+	iter->r_index = r_index;
+	iter->h_index = h_index;
+	iter->cur = NULL;
+}
+
+#define __INIT_PRIO_TREE_ROOT(ptr, _raw)	\
+do {					\
+	(ptr)->prio_tree_node = NULL;	\
+	(ptr)->index_bits = 1;		\
+	(ptr)->raw = (_raw);		\
+} while (0)
+
+#define INIT_PRIO_TREE_ROOT(ptr)	__INIT_PRIO_TREE_ROOT(ptr, 0)
+#define INIT_RAW_PRIO_TREE_ROOT(ptr)	__INIT_PRIO_TREE_ROOT(ptr, 1)
+
+#define INIT_PRIO_TREE_NODE(ptr)				\
+do {								\
+	(ptr)->left = (ptr)->right = (ptr)->parent = (ptr);	\
+} while (0)
+
+#define INIT_PRIO_TREE_ITER(ptr)	\
+do {					\
+	(ptr)->cur = NULL;		\
+	(ptr)->mask = 0UL;		\
+	(ptr)->value = 0UL;		\
+	(ptr)->size_level = 0;		\
+} while (0)
+
+#define prio_tree_entry(ptr, type, member) \
+       ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
+
+static inline int prio_tree_empty(const struct prio_tree_root *root)
+{
+	return root->prio_tree_node == NULL;
+}
+
+static inline int prio_tree_root(const struct prio_tree_node *node)
+{
+	return node->parent == node;
+}
+
+static inline int prio_tree_left_empty(const struct prio_tree_node *node)
+{
+	return node->left == node;
+}
+
+static inline int prio_tree_right_empty(const struct prio_tree_node *node)
+{
+	return node->right == node;
+}
+
+
+struct prio_tree_node *prio_tree_replace(struct prio_tree_root *root,
+                struct prio_tree_node *old, struct prio_tree_node *node);
+struct prio_tree_node *prio_tree_insert(struct prio_tree_root *root,
+                struct prio_tree_node *node);
+void prio_tree_remove(struct prio_tree_root *root, struct prio_tree_node *node);
+struct prio_tree_node *prio_tree_next(struct prio_tree_iter *iter);
+
+#define raw_prio_tree_replace(root, old, node) \
+	prio_tree_replace(root, (struct prio_tree_node *) (old), \
+	    (struct prio_tree_node *) (node))
+#define raw_prio_tree_insert(root, node) \
+	prio_tree_insert(root, (struct prio_tree_node *) (node))
+#define raw_prio_tree_remove(root, node) \
+	prio_tree_remove(root, (struct prio_tree_node *) (node))
+
+#endif /* _LINUX_PRIO_TREE_H */