Commit | Line | Data |
---|---|---|
2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
8f6f19dd | 2 | /* bit search implementation |
1da177e4 LT |
3 | * |
4 | * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. | |
5 | * Written by David Howells (dhowells@redhat.com) | |
6 | * | |
8f6f19dd YN |
7 | * Copyright (C) 2008 IBM Corporation |
8 | * 'find_last_bit' is written by Rusty Russell <rusty@rustcorp.com.au> | |
9 | * (Inspired by David Howell's find_next_bit implementation) | |
10 | * | |
2c57a0e2 YN |
11 | * Rewritten by Yury Norov <yury.norov@gmail.com> to decrease |
12 | * size and improve performance, 2015. | |
1da177e4 LT |
13 | */ |
14 | ||
15 | #include <linux/bitops.h> | |
8f6f19dd | 16 | #include <linux/bitmap.h> |
8bc3bcc9 | 17 | #include <linux/export.h> |
2c57a0e2 | 18 | #include <linux/kernel.h> |
1da177e4 | 19 | |
b78c5713 YN |
20 | #if !defined(find_next_bit) || !defined(find_next_zero_bit) || \ |
21 | !defined(find_next_bit_le) || !defined(find_next_zero_bit_le) || \ | |
22 | !defined(find_next_and_bit) | |
64970b68 | 23 | /* |
0ade34c3 CC |
24 | * This is a common helper function for find_next_bit, find_next_zero_bit, and |
25 | * find_next_and_bit. The differences are: | |
26 | * - The "invert" argument, which is XORed with each fetched word before | |
27 | * searching it for one bits. | |
28 | * - The optional "addr2", which is anded with "addr1" if present. | |
c7f612cd | 29 | */ |
7dfaa98f | 30 | static unsigned long _find_next_bit(const unsigned long *addr1, |
0ade34c3 | 31 | const unsigned long *addr2, unsigned long nbits, |
b78c5713 | 32 | unsigned long start, unsigned long invert, unsigned long le) |
1da177e4 | 33 | { |
b78c5713 | 34 | unsigned long tmp, mask; |
1da177e4 | 35 | |
e4afd2e5 | 36 | if (unlikely(start >= nbits)) |
2c57a0e2 YN |
37 | return nbits; |
38 | ||
0ade34c3 CC |
39 | tmp = addr1[start / BITS_PER_LONG]; |
40 | if (addr2) | |
41 | tmp &= addr2[start / BITS_PER_LONG]; | |
42 | tmp ^= invert; | |
2c57a0e2 YN |
43 | |
44 | /* Handle 1st word. */ | |
b78c5713 YN |
45 | mask = BITMAP_FIRST_WORD_MASK(start); |
46 | if (le) | |
47 | mask = swab(mask); | |
48 | ||
49 | tmp &= mask; | |
50 | ||
2c57a0e2 YN |
51 | start = round_down(start, BITS_PER_LONG); |
52 | ||
53 | while (!tmp) { | |
54 | start += BITS_PER_LONG; | |
55 | if (start >= nbits) | |
56 | return nbits; | |
57 | ||
0ade34c3 CC |
58 | tmp = addr1[start / BITS_PER_LONG]; |
59 | if (addr2) | |
60 | tmp &= addr2[start / BITS_PER_LONG]; | |
61 | tmp ^= invert; | |
1da177e4 LT |
62 | } |
63 | ||
b78c5713 YN |
64 | if (le) |
65 | tmp = swab(tmp); | |
66 | ||
2c57a0e2 | 67 | return min(start + __ffs(tmp), nbits); |
c7f612cd | 68 | } |
19de85ef | 69 | #endif |
1da177e4 | 70 | |
2c57a0e2 | 71 | #ifndef find_next_bit |
c7f612cd | 72 | /* |
2c57a0e2 | 73 | * Find the next set bit in a memory region. |
c7f612cd | 74 | */ |
2c57a0e2 YN |
75 | unsigned long find_next_bit(const unsigned long *addr, unsigned long size, |
76 | unsigned long offset) | |
77 | { | |
b78c5713 | 78 | return _find_next_bit(addr, NULL, size, offset, 0UL, 0); |
2c57a0e2 YN |
79 | } |
80 | EXPORT_SYMBOL(find_next_bit); | |
81 | #endif | |
82 | ||
83 | #ifndef find_next_zero_bit | |
fee4b19f TG |
84 | unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size, |
85 | unsigned long offset) | |
c7f612cd | 86 | { |
b78c5713 | 87 | return _find_next_bit(addr, NULL, size, offset, ~0UL, 0); |
1da177e4 | 88 | } |
fee4b19f | 89 | EXPORT_SYMBOL(find_next_zero_bit); |
19de85ef | 90 | #endif |
77b9bd9c | 91 | |
0ade34c3 CC |
92 | #if !defined(find_next_and_bit) |
93 | unsigned long find_next_and_bit(const unsigned long *addr1, | |
94 | const unsigned long *addr2, unsigned long size, | |
95 | unsigned long offset) | |
96 | { | |
b78c5713 | 97 | return _find_next_bit(addr1, addr2, size, offset, 0UL, 0); |
0ade34c3 CC |
98 | } |
99 | EXPORT_SYMBOL(find_next_and_bit); | |
100 | #endif | |
101 | ||
19de85ef | 102 | #ifndef find_first_bit |
77b9bd9c AH |
103 | /* |
104 | * Find the first set bit in a memory region. | |
105 | */ | |
fee4b19f | 106 | unsigned long find_first_bit(const unsigned long *addr, unsigned long size) |
77b9bd9c | 107 | { |
2c57a0e2 | 108 | unsigned long idx; |
77b9bd9c | 109 | |
2c57a0e2 YN |
110 | for (idx = 0; idx * BITS_PER_LONG < size; idx++) { |
111 | if (addr[idx]) | |
112 | return min(idx * BITS_PER_LONG + __ffs(addr[idx]), size); | |
77b9bd9c | 113 | } |
77b9bd9c | 114 | |
2c57a0e2 | 115 | return size; |
77b9bd9c | 116 | } |
fee4b19f | 117 | EXPORT_SYMBOL(find_first_bit); |
19de85ef | 118 | #endif |
77b9bd9c | 119 | |
19de85ef | 120 | #ifndef find_first_zero_bit |
77b9bd9c AH |
121 | /* |
122 | * Find the first cleared bit in a memory region. | |
123 | */ | |
fee4b19f | 124 | unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size) |
77b9bd9c | 125 | { |
2c57a0e2 | 126 | unsigned long idx; |
77b9bd9c | 127 | |
2c57a0e2 YN |
128 | for (idx = 0; idx * BITS_PER_LONG < size; idx++) { |
129 | if (addr[idx] != ~0UL) | |
130 | return min(idx * BITS_PER_LONG + ffz(addr[idx]), size); | |
77b9bd9c | 131 | } |
77b9bd9c | 132 | |
2c57a0e2 | 133 | return size; |
77b9bd9c | 134 | } |
fee4b19f | 135 | EXPORT_SYMBOL(find_first_zero_bit); |
19de85ef | 136 | #endif |
930ae745 | 137 | |
8f6f19dd YN |
138 | #ifndef find_last_bit |
139 | unsigned long find_last_bit(const unsigned long *addr, unsigned long size) | |
140 | { | |
141 | if (size) { | |
142 | unsigned long val = BITMAP_LAST_WORD_MASK(size); | |
143 | unsigned long idx = (size-1) / BITS_PER_LONG; | |
144 | ||
145 | do { | |
146 | val &= addr[idx]; | |
147 | if (val) | |
148 | return idx * BITS_PER_LONG + __fls(val); | |
149 | ||
150 | val = ~0ul; | |
151 | } while (idx--); | |
152 | } | |
153 | return size; | |
154 | } | |
155 | EXPORT_SYMBOL(find_last_bit); | |
156 | #endif | |
157 | ||
930ae745 AM |
158 | #ifdef __BIG_ENDIAN |
159 | ||
2c57a0e2 YN |
160 | #ifndef find_next_zero_bit_le |
161 | unsigned long find_next_zero_bit_le(const void *addr, unsigned | |
162 | long size, unsigned long offset) | |
163 | { | |
b78c5713 | 164 | return _find_next_bit(addr, NULL, size, offset, ~0UL, 1); |
930ae745 | 165 | } |
c4945b9e | 166 | EXPORT_SYMBOL(find_next_zero_bit_le); |
19de85ef | 167 | #endif |
930ae745 | 168 | |
19de85ef | 169 | #ifndef find_next_bit_le |
a56560b3 | 170 | unsigned long find_next_bit_le(const void *addr, unsigned |
aa02ad67 AK |
171 | long size, unsigned long offset) |
172 | { | |
b78c5713 | 173 | return _find_next_bit(addr, NULL, size, offset, 0UL, 1); |
aa02ad67 | 174 | } |
c4945b9e | 175 | EXPORT_SYMBOL(find_next_bit_le); |
19de85ef | 176 | #endif |
0664996b | 177 | |
930ae745 | 178 | #endif /* __BIG_ENDIAN */ |
169c474f WBG |
179 | |
180 | unsigned long find_next_clump8(unsigned long *clump, const unsigned long *addr, | |
181 | unsigned long size, unsigned long offset) | |
182 | { | |
183 | offset = find_next_bit(addr, size, offset); | |
184 | if (offset == size) | |
185 | return size; | |
186 | ||
187 | offset = round_down(offset, 8); | |
188 | *clump = bitmap_get_value8(addr, offset); | |
189 | ||
190 | return offset; | |
191 | } | |
192 | EXPORT_SYMBOL(find_next_clump8); |