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Commit | Line | Data |
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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> |
b296a6d5 | 19 | #include <linux/minmax.h> |
1da177e4 | 20 | |
b78c5713 YN |
21 | #if !defined(find_next_bit) || !defined(find_next_zero_bit) || \ |
22 | !defined(find_next_bit_le) || !defined(find_next_zero_bit_le) || \ | |
23 | !defined(find_next_and_bit) | |
64970b68 | 24 | /* |
0ade34c3 CC |
25 | * This is a common helper function for find_next_bit, find_next_zero_bit, and |
26 | * find_next_and_bit. The differences are: | |
27 | * - The "invert" argument, which is XORed with each fetched word before | |
28 | * searching it for one bits. | |
29 | * - The optional "addr2", which is anded with "addr1" if present. | |
c7f612cd | 30 | */ |
7dfaa98f | 31 | static unsigned long _find_next_bit(const unsigned long *addr1, |
0ade34c3 | 32 | const unsigned long *addr2, unsigned long nbits, |
b78c5713 | 33 | unsigned long start, unsigned long invert, unsigned long le) |
1da177e4 | 34 | { |
b78c5713 | 35 | unsigned long tmp, mask; |
1da177e4 | 36 | |
e4afd2e5 | 37 | if (unlikely(start >= nbits)) |
2c57a0e2 YN |
38 | return nbits; |
39 | ||
0ade34c3 CC |
40 | tmp = addr1[start / BITS_PER_LONG]; |
41 | if (addr2) | |
42 | tmp &= addr2[start / BITS_PER_LONG]; | |
43 | tmp ^= invert; | |
2c57a0e2 YN |
44 | |
45 | /* Handle 1st word. */ | |
b78c5713 YN |
46 | mask = BITMAP_FIRST_WORD_MASK(start); |
47 | if (le) | |
48 | mask = swab(mask); | |
49 | ||
50 | tmp &= mask; | |
51 | ||
2c57a0e2 YN |
52 | start = round_down(start, BITS_PER_LONG); |
53 | ||
54 | while (!tmp) { | |
55 | start += BITS_PER_LONG; | |
56 | if (start >= nbits) | |
57 | return nbits; | |
58 | ||
0ade34c3 CC |
59 | tmp = addr1[start / BITS_PER_LONG]; |
60 | if (addr2) | |
61 | tmp &= addr2[start / BITS_PER_LONG]; | |
62 | tmp ^= invert; | |
1da177e4 LT |
63 | } |
64 | ||
b78c5713 YN |
65 | if (le) |
66 | tmp = swab(tmp); | |
67 | ||
2c57a0e2 | 68 | return min(start + __ffs(tmp), nbits); |
c7f612cd | 69 | } |
19de85ef | 70 | #endif |
1da177e4 | 71 | |
2c57a0e2 | 72 | #ifndef find_next_bit |
c7f612cd | 73 | /* |
2c57a0e2 | 74 | * Find the next set bit in a memory region. |
c7f612cd | 75 | */ |
2c57a0e2 YN |
76 | unsigned long find_next_bit(const unsigned long *addr, unsigned long size, |
77 | unsigned long offset) | |
78 | { | |
b78c5713 | 79 | return _find_next_bit(addr, NULL, size, offset, 0UL, 0); |
2c57a0e2 YN |
80 | } |
81 | EXPORT_SYMBOL(find_next_bit); | |
82 | #endif | |
83 | ||
84 | #ifndef find_next_zero_bit | |
fee4b19f TG |
85 | unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size, |
86 | unsigned long offset) | |
c7f612cd | 87 | { |
b78c5713 | 88 | return _find_next_bit(addr, NULL, size, offset, ~0UL, 0); |
1da177e4 | 89 | } |
fee4b19f | 90 | EXPORT_SYMBOL(find_next_zero_bit); |
19de85ef | 91 | #endif |
77b9bd9c | 92 | |
0ade34c3 CC |
93 | #if !defined(find_next_and_bit) |
94 | unsigned long find_next_and_bit(const unsigned long *addr1, | |
95 | const unsigned long *addr2, unsigned long size, | |
96 | unsigned long offset) | |
97 | { | |
b78c5713 | 98 | return _find_next_bit(addr1, addr2, size, offset, 0UL, 0); |
0ade34c3 CC |
99 | } |
100 | EXPORT_SYMBOL(find_next_and_bit); | |
101 | #endif | |
102 | ||
19de85ef | 103 | #ifndef find_first_bit |
77b9bd9c AH |
104 | /* |
105 | * Find the first set bit in a memory region. | |
106 | */ | |
fee4b19f | 107 | unsigned long find_first_bit(const unsigned long *addr, unsigned long size) |
77b9bd9c | 108 | { |
2c57a0e2 | 109 | unsigned long idx; |
77b9bd9c | 110 | |
2c57a0e2 YN |
111 | for (idx = 0; idx * BITS_PER_LONG < size; idx++) { |
112 | if (addr[idx]) | |
113 | return min(idx * BITS_PER_LONG + __ffs(addr[idx]), size); | |
77b9bd9c | 114 | } |
77b9bd9c | 115 | |
2c57a0e2 | 116 | return size; |
77b9bd9c | 117 | } |
fee4b19f | 118 | EXPORT_SYMBOL(find_first_bit); |
19de85ef | 119 | #endif |
77b9bd9c | 120 | |
19de85ef | 121 | #ifndef find_first_zero_bit |
77b9bd9c AH |
122 | /* |
123 | * Find the first cleared bit in a memory region. | |
124 | */ | |
fee4b19f | 125 | unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size) |
77b9bd9c | 126 | { |
2c57a0e2 | 127 | unsigned long idx; |
77b9bd9c | 128 | |
2c57a0e2 YN |
129 | for (idx = 0; idx * BITS_PER_LONG < size; idx++) { |
130 | if (addr[idx] != ~0UL) | |
131 | return min(idx * BITS_PER_LONG + ffz(addr[idx]), size); | |
77b9bd9c | 132 | } |
77b9bd9c | 133 | |
2c57a0e2 | 134 | return size; |
77b9bd9c | 135 | } |
fee4b19f | 136 | EXPORT_SYMBOL(find_first_zero_bit); |
19de85ef | 137 | #endif |
930ae745 | 138 | |
8f6f19dd YN |
139 | #ifndef find_last_bit |
140 | unsigned long find_last_bit(const unsigned long *addr, unsigned long size) | |
141 | { | |
142 | if (size) { | |
143 | unsigned long val = BITMAP_LAST_WORD_MASK(size); | |
144 | unsigned long idx = (size-1) / BITS_PER_LONG; | |
145 | ||
146 | do { | |
147 | val &= addr[idx]; | |
148 | if (val) | |
149 | return idx * BITS_PER_LONG + __fls(val); | |
150 | ||
151 | val = ~0ul; | |
152 | } while (idx--); | |
153 | } | |
154 | return size; | |
155 | } | |
156 | EXPORT_SYMBOL(find_last_bit); | |
157 | #endif | |
158 | ||
930ae745 AM |
159 | #ifdef __BIG_ENDIAN |
160 | ||
2c57a0e2 YN |
161 | #ifndef find_next_zero_bit_le |
162 | unsigned long find_next_zero_bit_le(const void *addr, unsigned | |
163 | long size, unsigned long offset) | |
164 | { | |
b78c5713 | 165 | return _find_next_bit(addr, NULL, size, offset, ~0UL, 1); |
930ae745 | 166 | } |
c4945b9e | 167 | EXPORT_SYMBOL(find_next_zero_bit_le); |
19de85ef | 168 | #endif |
930ae745 | 169 | |
19de85ef | 170 | #ifndef find_next_bit_le |
a56560b3 | 171 | unsigned long find_next_bit_le(const void *addr, unsigned |
aa02ad67 AK |
172 | long size, unsigned long offset) |
173 | { | |
b78c5713 | 174 | return _find_next_bit(addr, NULL, size, offset, 0UL, 1); |
aa02ad67 | 175 | } |
c4945b9e | 176 | EXPORT_SYMBOL(find_next_bit_le); |
19de85ef | 177 | #endif |
0664996b | 178 | |
930ae745 | 179 | #endif /* __BIG_ENDIAN */ |
169c474f WBG |
180 | |
181 | unsigned long find_next_clump8(unsigned long *clump, const unsigned long *addr, | |
182 | unsigned long size, unsigned long offset) | |
183 | { | |
184 | offset = find_next_bit(addr, size, offset); | |
185 | if (offset == size) | |
186 | return size; | |
187 | ||
188 | offset = round_down(offset, 8); | |
189 | *clump = bitmap_get_value8(addr, offset); | |
190 | ||
191 | return offset; | |
192 | } | |
193 | EXPORT_SYMBOL(find_next_clump8); |