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/*
* Copyright (C) 2007 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* 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., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include "bit-radix.h"
#define BIT_ARRAY_BYTES 256
#define BIT_RADIX_BITS_PER_ARRAY ((BIT_ARRAY_BYTES - sizeof(unsigned long)) * 8)
extern struct kmem_cache *btrfs_bit_radix_cachep;
int set_radix_bit(struct radix_tree_root *radix, unsigned long bit)
{
unsigned long *bits;
unsigned long slot;
int bit_slot;
int ret;
slot = bit / BIT_RADIX_BITS_PER_ARRAY;
bit_slot = bit % BIT_RADIX_BITS_PER_ARRAY;
bits = radix_tree_lookup(radix, slot);
if (!bits) {
bits = kmem_cache_alloc(btrfs_bit_radix_cachep, GFP_NOFS);
if (!bits)
return -ENOMEM;
memset(bits + 1, 0, BIT_ARRAY_BYTES - sizeof(unsigned long));
bits[0] = slot;
ret = radix_tree_insert(radix, slot, bits);
if (ret)
return ret;
}
ret = test_and_set_bit(bit_slot, bits + 1);
if (ret < 0)
ret = 1;
return ret;
}
int test_radix_bit(struct radix_tree_root *radix, unsigned long bit)
{
unsigned long *bits;
unsigned long slot;
int bit_slot;
slot = bit / BIT_RADIX_BITS_PER_ARRAY;
bit_slot = bit % BIT_RADIX_BITS_PER_ARRAY;
bits = radix_tree_lookup(radix, slot);
if (!bits)
return 0;
return test_bit(bit_slot, bits + 1);
}
int clear_radix_bit(struct radix_tree_root *radix, unsigned long bit)
{
unsigned long *bits;
unsigned long slot;
int bit_slot;
int i;
int empty = 1;
slot = bit / BIT_RADIX_BITS_PER_ARRAY;
bit_slot = bit % BIT_RADIX_BITS_PER_ARRAY;
bits = radix_tree_lookup(radix, slot);
if (!bits)
return 0;
clear_bit(bit_slot, bits + 1);
for (i = 1; i < BIT_ARRAY_BYTES / sizeof(unsigned long); i++) {
if (bits[i]) {
empty = 0;
break;
}
}
if (empty) {
bits = radix_tree_delete(radix, slot);
BUG_ON(!bits);
kmem_cache_free(btrfs_bit_radix_cachep, bits);
}
return 0;
}
int find_first_radix_bit(struct radix_tree_root *radix, unsigned long *retbits,
unsigned long start, int nr)
{
unsigned long *bits;
unsigned long *gang[4];
int found;
int ret;
int i;
int total_found = 0;
unsigned long slot;
slot = start / BIT_RADIX_BITS_PER_ARRAY;
ret = radix_tree_gang_lookup(radix, (void **)gang, slot,
ARRAY_SIZE(gang));
found = start % BIT_RADIX_BITS_PER_ARRAY;
for (i = 0; i < ret && nr > 0; i++) {
bits = gang[i];
while(nr > 0) {
found = find_next_bit(bits + 1,
BIT_RADIX_BITS_PER_ARRAY,
found);
if (found < BIT_RADIX_BITS_PER_ARRAY) {
*retbits = bits[0] *
BIT_RADIX_BITS_PER_ARRAY + found;
retbits++;
nr--;
total_found++;
found++;
} else
break;
}
found = 0;
}
return total_found;
}
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