1/*-
  2 * SPDX-License-Identifier: BSD-3-Clause
  3 *
  4 * Copyright (c) 1998 Matthew Dillon.  All Rights Reserved.
  5 * Redistribution and use in source and binary forms, with or without
  6 * modification, are permitted provided that the following conditions
  7 * are met:
  8 * 1. Redistributions of source code must retain the above copyright
  9 *    notice, this list of conditions and the following disclaimer.
 10 * 2. Redistributions in binary form must reproduce the above copyright
 11 *    notice, this list of conditions and the following disclaimer in the
 12 *    documentation and/or other materials provided with the distribution.
 13 * 3. Neither the name of the University nor the names of its contributors
 14 *    may be used to endorse or promote products derived from this software
 15 *    without specific prior written permission.
 16 *
 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
 18 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 23 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 25 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 26 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 27 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 28 */
 29
 30/*
 31 * Implements bitmap resource lists.
 32 *
 33 *	Usage:
 34 *		blist = blist_create(blocks, flags)
 35 *		(void)  blist_destroy(blist)
 36 *		blkno = blist_alloc(blist, &count, maxcount)
 37 *		(void)  blist_free(blist, blkno, count)
 38 *		nblks = blist_fill(blist, blkno, count)
 39 *		(void)  blist_resize(&blist, count, freeextra, flags)
 40 *		
 41 *
 42 *	Notes:
 43 *		on creation, the entire list is marked reserved.  You should
 44 *		first blist_free() the sections you want to make available
 45 *		for allocation before doing general blist_alloc()/free()
 46 *		ops.
 47 *
 48 *		SWAPBLK_NONE is returned on failure.  This module is typically
 49 *		capable of managing up to (2^63) blocks per blist, though
 50 *		the memory utilization would be insane if you actually did
 51 *		that.  Managing something like 512MB worth of 4K blocks 
 52 *		eats around 32 KBytes of memory. 
 53
 54 */
 55
 56#ifndef _SYS_BLIST_H_
 57#define _SYS_BLIST_H_
 58
 59typedef	uint64_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 * Both blmeta and bm_bitmap MUST be a power of 2 in size.
 71 */
 72
 73typedef struct blmeta {
 74	u_daddr_t	bm_bitmap;	/* marking unfilled block sets	*/
 75	daddr_t		bm_bighint;	/* biggest contiguous block hint*/
 76} blmeta_t;
 77
 78typedef struct blist {
 79	daddr_t		bl_blocks;	/* area of coverage		*/
 80	daddr_t		bl_avail;	/* # available blocks		*/
 81	u_daddr_t	bl_radix;	/* coverage radix		*/
 82	daddr_t		bl_cursor;	/* next-fit search starts at	*/
 83	blmeta_t	bl_root[1];	/* root of radix tree		*/
 84} *blist_t;
 85
 86#define BLIST_RADIX		(sizeof(u_daddr_t) * 8)
 87
 88#define BLIST_MAX_ALLOC		BLIST_RADIX
 89
 90struct sbuf;
 91
 92daddr_t	blist_alloc(blist_t blist, int *count, int maxcount);
 93daddr_t	blist_avail(blist_t blist);
 94blist_t	blist_create(daddr_t blocks, int flags);
 95void	blist_destroy(blist_t blist);
 96daddr_t	blist_fill(blist_t bl, daddr_t blkno, daddr_t count);
 97void	blist_free(blist_t blist, daddr_t blkno, daddr_t count);
 98void	blist_print(blist_t blist);
 99void	blist_resize(blist_t *pblist, daddr_t count, int freenew, int flags);
100void	blist_stats(blist_t blist, struct sbuf *s);
101
102#endif	/* _SYS_BLIST_H_ */