radix-tree.h revision 219820 
1/*-
2 * Copyright (c) 2010 Isilon Systems, Inc.
3 * Copyright (c) 2010 iX Systems, Inc.
4 * Copyright (c) 2010 Panasas, Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice unmodified, this list of conditions, and the following
12 *    disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#ifndef	_LINUX_RADIX_TREE_H_
30#define	_LINUX_RADIX_TREE_H_
31
32#define	RADIX_TREE_MAP_SHIFT	6
33#define	RADIX_TREE_MAP_SIZE	(1 << RADIX_TREE_MAP_SHIFT)
34#define	RADIX_TREE_MAP_MASK	(RADIX_TREE_MAP_SIZE - 1)
35#define	RADIX_TREE_MAX_HEIGHT						\
36	    DIV_ROUND_UP((sizeof(long) * NBBY), RADIX_TREE_MAP_SHIFT)
37
38struct radix_tree_node {
39	void		*slots[RADIX_TREE_MAP_SIZE];
40	int		count;
41};
42
43struct radix_tree_root {
44	struct radix_tree_node	*rnode;
45	gfp_t			gfp_mask;
46	int			height;
47};
48
49#define	RADIX_TREE_INIT(mask)						\
50	    { .rnode = NULL, .gfp_mask = mask, .height = 0 };
51#define	INIT_RADIX_TREE(root, mask)					\
52	    { (root)->rnode = NULL; (root)->gfp_mask = mask; (root)->height = 0; }
53#define	RADIX_TREE(name, mask)						\
54	    struct radix_tree_root name = RADIX_TREE_INIT(mask)
55
56void	*radix_tree_lookup(struct radix_tree_root *, unsigned long);
57void	*radix_tree_delete(struct radix_tree_root *, unsigned long);
58int	radix_tree_insert(struct radix_tree_root *, unsigned long, void *);
59
60#endif	/* _LINUX_RADIX_TREE_H_ */
61