diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
new file mode 100644
index 0000000..8081a28
--- /dev/null
+++ b/include/linux/radix-tree.h
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2001 Momchil Velikov
+ * Portions Copyright (C) 2001 Christoph Hellwig
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2, or (at
+ * your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#ifndef _LINUX_RADIX_TREE_H
+#define _LINUX_RADIX_TREE_H
+
+#include <linux/preempt.h>
+#include <linux/types.h>
+
+struct radix_tree_root {
+	unsigned int		height;
+	int			gfp_mask;
+	struct radix_tree_node	*rnode;
+};
+
+#define RADIX_TREE_INIT(mask)	{					\
+	.height = 0,							\
+	.gfp_mask = (mask),						\
+	.rnode = NULL,							\
+}
+
+#define RADIX_TREE(name, mask) \
+	struct radix_tree_root name = RADIX_TREE_INIT(mask)
+
+#define INIT_RADIX_TREE(root, mask)					\
+do {									\
+	(root)->height = 0;						\
+	(root)->gfp_mask = (mask);					\
+	(root)->rnode = NULL;						\
+} while (0)
+
+int radix_tree_insert(struct radix_tree_root *, unsigned long, void *);
+void *radix_tree_lookup(struct radix_tree_root *, unsigned long);
+void *radix_tree_delete(struct radix_tree_root *, unsigned long);
+unsigned int
+radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
+			unsigned long first_index, unsigned int max_items);
+int radix_tree_preload(int gfp_mask);
+void radix_tree_init(void);
+void *radix_tree_tag_set(struct radix_tree_root *root,
+			unsigned long index, int tag);
+void *radix_tree_tag_clear(struct radix_tree_root *root,
+			unsigned long index, int tag);
+int radix_tree_tag_get(struct radix_tree_root *root,
+			unsigned long index, int tag);
+unsigned int
+radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,
+		unsigned long first_index, unsigned int max_items, int tag);
+int radix_tree_tagged(struct radix_tree_root *root, int tag);
+
+static inline void radix_tree_preload_end(void)
+{
+	preempt_enable();
+}
+
+#endif /* _LINUX_RADIX_TREE_H */