| Chris Mason | 8ef9762 | 2007-03-26 10:15:30 -0400 | [diff] [blame] | 1 | #include <linux/module.h> |
| 2 | #include "bit-radix.h" |
| 3 | |
| 4 | #define BIT_ARRAY_BYTES 256 |
| 5 | #define BIT_RADIX_BITS_PER_ARRAY ((BIT_ARRAY_BYTES - sizeof(unsigned long)) * 8) |
| 6 | |
| 7 | int set_radix_bit(struct radix_tree_root *radix, unsigned long bit) |
| 8 | { |
| 9 | unsigned long *bits; |
| 10 | unsigned long slot; |
| 11 | int bit_slot; |
| 12 | int ret; |
| 13 | |
| 14 | slot = bit / BIT_RADIX_BITS_PER_ARRAY; |
| 15 | bit_slot = bit % BIT_RADIX_BITS_PER_ARRAY; |
| 16 | |
| 17 | bits = radix_tree_lookup(radix, slot); |
| 18 | if (!bits) { |
| 19 | bits = kmalloc(BIT_ARRAY_BYTES, GFP_NOIO); |
| 20 | if (!bits) |
| 21 | return -ENOMEM; |
| 22 | memset(bits + 1, 0, BIT_ARRAY_BYTES - sizeof(unsigned long)); |
| 23 | bits[0] = slot; |
| 24 | ret = radix_tree_insert(radix, slot, bits); |
| 25 | if (ret) |
| 26 | return ret; |
| 27 | } |
| 28 | set_bit(bit_slot, bits + 1); |
| 29 | return 0; |
| 30 | } |
| 31 | |
| 32 | int test_radix_bit(struct radix_tree_root *radix, unsigned long bit) |
| 33 | { |
| 34 | unsigned long *bits; |
| 35 | unsigned long slot; |
| 36 | int bit_slot; |
| 37 | |
| 38 | slot = bit / BIT_RADIX_BITS_PER_ARRAY; |
| 39 | bit_slot = bit % BIT_RADIX_BITS_PER_ARRAY; |
| 40 | |
| 41 | bits = radix_tree_lookup(radix, slot); |
| 42 | if (!bits) |
| 43 | return 0; |
| 44 | return test_bit(bit_slot, bits + 1); |
| 45 | } |
| 46 | |
| 47 | int clear_radix_bit(struct radix_tree_root *radix, unsigned long bit) |
| 48 | { |
| 49 | unsigned long *bits; |
| 50 | unsigned long slot; |
| 51 | int bit_slot; |
| 52 | int i; |
| 53 | int empty = 1; |
| 54 | |
| 55 | slot = bit / BIT_RADIX_BITS_PER_ARRAY; |
| 56 | bit_slot = bit % BIT_RADIX_BITS_PER_ARRAY; |
| 57 | |
| 58 | bits = radix_tree_lookup(radix, slot); |
| 59 | if (!bits) |
| 60 | return 0; |
| 61 | clear_bit(bit_slot, bits + 1); |
| 62 | |
| 63 | for (i = 1; i < BIT_ARRAY_BYTES / sizeof(unsigned long); i++) { |
| 64 | if (bits[i]) { |
| 65 | empty = 0; |
| 66 | break; |
| 67 | } |
| 68 | } |
| 69 | |
| 70 | if (empty) { |
| 71 | bits = radix_tree_delete(radix, slot); |
| 72 | BUG_ON(!bits); |
| 73 | } |
| 74 | return 0; |
| 75 | } |
| 76 | |
| 77 | int find_first_radix_bit(struct radix_tree_root *radix, unsigned long *retbits, |
| 78 | int nr) |
| 79 | { |
| 80 | unsigned long *bits; |
| 81 | unsigned long *gang[4]; |
| 82 | int found; |
| 83 | int ret; |
| 84 | int i; |
| 85 | int total_found = 0; |
| 86 | |
| 87 | ret = radix_tree_gang_lookup(radix, (void *)&gang, 0, ARRAY_SIZE(gang)); |
| 88 | for (i = 0; i < ret && nr > 0; i++) { |
| 89 | found = 0; |
| 90 | bits = gang[i]; |
| 91 | while(nr > 0) { |
| 92 | found = find_next_bit(bits + 1, |
| 93 | BIT_RADIX_BITS_PER_ARRAY, |
| 94 | found); |
| 95 | if (found < BIT_RADIX_BITS_PER_ARRAY) { |
| 96 | *retbits = bits[0] * |
| 97 | BIT_RADIX_BITS_PER_ARRAY + found; |
| 98 | retbits++; |
| 99 | nr--; |
| 100 | total_found++; |
| 101 | found++; |
| 102 | } else |
| 103 | break; |
| 104 | } |
| 105 | } |
| 106 | return total_found; |
| 107 | } |