105 lines
3.8 KiB
C
105 lines
3.8 KiB
C
/*-
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* Copyright (c) 1998 Matthew Dillon. All Rights Reserved.
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Implements bitmap resource lists.
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*
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* Usage:
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* blist = blist_create(blocks, flags)
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* (void) blist_destroy(blist)
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* blkno = blist_alloc(blist, count)
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* (void) blist_free(blist, blkno, count)
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* nblks = blist_fill(blist, blkno, count)
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* (void) blist_resize(&blist, count, freeextra, flags)
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*
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*
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* Notes:
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* on creation, the entire list is marked reserved. You should
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* first blist_free() the sections you want to make available
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* for allocation before doing general blist_alloc()/free()
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* ops.
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*
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* SWAPBLK_NONE is returned on failure. This module is typically
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* capable of managing up to (2^31) blocks per blist, though
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* the memory utilization would be insane if you actually did
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* that. Managing something like 512MB worth of 4K blocks
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* eats around 32 KBytes of memory.
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*
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* $FreeBSD$
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*/
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#ifndef _SYS_BLIST_H_
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#define _SYS_BLIST_H_
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typedef u_int32_t u_daddr_t; /* unsigned disk address */
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/*
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* note: currently use SWAPBLK_NONE as an absolute value rather then
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* a flag bit.
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*/
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#define SWAPBLK_MASK ((daddr_t)((u_daddr_t)-1 >> 1)) /* mask */
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#define SWAPBLK_NONE ((daddr_t)((u_daddr_t)SWAPBLK_MASK + 1))/* flag */
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/*
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* blmeta and bl_bitmap_t MUST be a power of 2 in size.
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*/
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typedef struct blmeta {
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union {
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daddr_t bmu_avail; /* space available under us */
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u_daddr_t bmu_bitmap; /* bitmap if we are a leaf */
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} u;
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daddr_t bm_bighint; /* biggest contiguous block hint*/
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} blmeta_t;
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typedef struct blist {
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daddr_t bl_blocks; /* area of coverage */
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daddr_t bl_radix; /* coverage radix */
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daddr_t bl_skip; /* starting skip */
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daddr_t bl_free; /* number of free blocks */
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blmeta_t *bl_root; /* root of radix tree */
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daddr_t bl_rootblks; /* daddr_t blks allocated for tree */
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} *blist_t;
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#define BLIST_META_RADIX 16
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#define BLIST_BMAP_RADIX (sizeof(u_daddr_t)*8)
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#define BLIST_MAX_ALLOC BLIST_BMAP_RADIX
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extern blist_t blist_create(daddr_t blocks, int flags);
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extern void blist_destroy(blist_t blist);
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extern daddr_t blist_alloc(blist_t blist, daddr_t count);
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extern void blist_free(blist_t blist, daddr_t blkno, daddr_t count);
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extern int blist_fill(blist_t bl, daddr_t blkno, daddr_t count);
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extern void blist_print(blist_t blist);
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extern void blist_resize(blist_t *pblist, daddr_t count, int freenew, int flags);
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#endif /* _SYS_BLIST_H_ */
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