1/*-
2 * Copyright (c) 1998 Matthew Dillon.  All Rights Reserved.
3 * Redistribution and use in source and binary forms, with or without
4 * modification, are permitted provided that the following conditions
5 * are met:
6 * 1. Redistributions of source code must retain the above copyright
7 *    notice, this list of conditions and the following disclaimer.
8 * 2. Redistributions in binary form must reproduce the above copyright
9 *    notice, this list of conditions and the following disclaimer in the
10 *    documentation and/or other materials provided with the distribution.
11 * 4. Neither the name of the University nor the names of its contributors
12 *    may be used to endorse or promote products derived from this software
13 *    without specific prior written permission.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
19 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
21 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
22 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
24 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
25 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28/*
29 * Implements bitmap resource lists.
30 *
31 *	Usage:
32 *		blist = blist_create(blocks, flags)
33 *		(void)  blist_destroy(blist)
34 *		blkno = blist_alloc(blist, count)
35 *		(void)  blist_free(blist, blkno, count)
36 *		nblks = blist_fill(blist, blkno, count)
37 *		(void)  blist_resize(&blist, count, freeextra, flags)
38 *
39 *
40 *	Notes:
41 *		on creation, the entire list is marked reserved.  You should
42 *		first blist_free() the sections you want to make available
43 *		for allocation before doing general blist_alloc()/free()
44 *		ops.
45 *
46 *		SWAPBLK_NONE is returned on failure.  This module is typically
47 *		capable of managing up to (2^31) blocks per blist, though
48 *		the memory utilization would be insane if you actually did
49 *		that.  Managing something like 512MB worth of 4K blocks
50 *		eats around 32 KBytes of memory.
51 *
52 * $FreeBSD$
53
54 */
55
56#ifndef _SYS_BLIST_H_
57#define _SYS_BLIST_H_
58
59typedef	u_int32_t	u_daddr_t;	/* unsigned disk address */
60
61/*
62 * note: currently use SWAPBLK_NONE as an absolute value rather then
63 * a flag bit.
64 */
65
66#define SWAPBLK_MASK	((daddr_t)((u_daddr_t)-1 >> 1))		/* mask */
67#define SWAPBLK_NONE	((daddr_t)((u_daddr_t)SWAPBLK_MASK + 1))/* flag */
68
69/*
70 * blmeta and bl_bitmap_t MUST be a power of 2 in size.
71 */
72
73typedef struct blmeta {
74	union {
75	    daddr_t	bmu_avail;	/* space available under us	*/
76	    u_daddr_t	bmu_bitmap;	/* bitmap if we are a leaf	*/
77	} u;
78	daddr_t		bm_bighint;	/* biggest contiguous block hint*/
79} blmeta_t;
80
81typedef struct blist {
82	daddr_t		bl_blocks;	/* area of coverage		*/
83	daddr_t		bl_radix;	/* coverage radix		*/
84	daddr_t		bl_skip;	/* starting skip		*/
85	daddr_t		bl_free;	/* number of free blocks	*/
86	blmeta_t	*bl_root;	/* root of radix tree		*/
87	daddr_t		bl_rootblks;	/* daddr_t blks allocated for tree */
88} *blist_t;
89
90#define BLIST_META_RADIX	16
91#define BLIST_BMAP_RADIX	(sizeof(u_daddr_t)*8)
92
93#define BLIST_MAX_ALLOC		BLIST_BMAP_RADIX
94
95extern blist_t blist_create(daddr_t blocks, int flags);
96extern void blist_destroy(blist_t blist);
97extern daddr_t blist_alloc(blist_t blist, daddr_t count);
98extern void blist_free(blist_t blist, daddr_t blkno, daddr_t count);
99extern int blist_fill(blist_t bl, daddr_t blkno, daddr_t count);
100extern void blist_print(blist_t blist);
101extern void blist_resize(blist_t *pblist, daddr_t count, int freenew, int flags);
102
103#endif	/* _SYS_BLIST_H_ */
104
105