Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_GENERIC_BITOPS_FIND_H_
3#define _ASM_GENERIC_BITOPS_FIND_H_
4
5extern unsigned long _find_next_bit(const unsigned long *addr1,
6 const unsigned long *addr2, unsigned long nbits,
7 unsigned long start, unsigned long invert, unsigned long le);
8extern unsigned long _find_first_bit(const unsigned long *addr, unsigned long size);
9extern unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long size);
10extern unsigned long _find_last_bit(const unsigned long *addr, unsigned long size);
11
12#ifndef find_next_bit
13/**
14 * find_next_bit - find the next set bit in a memory region
15 * @addr: The address to base the search on
16 * @offset: The bitnumber to start searching at
17 * @size: The bitmap size in bits
18 *
19 * Returns the bit number for the next set bit
20 * If no bits are set, returns @size.
21 */
22static inline
23unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
24 unsigned long offset)
25{
26 if (small_const_nbits(size)) {
27 unsigned long val;
28
29 if (unlikely(offset >= size))
30 return size;
31
32 val = *addr & GENMASK(size - 1, offset);
33 return val ? __ffs(val) : size;
34 }
35
36 return _find_next_bit(addr, NULL, size, offset, 0UL, 0);
37}
38#endif
39
40#ifndef find_next_and_bit
41/**
42 * find_next_and_bit - find the next set bit in both memory regions
43 * @addr1: The first address to base the search on
44 * @addr2: The second address to base the search on
45 * @offset: The bitnumber to start searching at
46 * @size: The bitmap size in bits
47 *
48 * Returns the bit number for the next set bit
49 * If no bits are set, returns @size.
50 */
51static inline
52unsigned long find_next_and_bit(const unsigned long *addr1,
53 const unsigned long *addr2, unsigned long size,
54 unsigned long offset)
55{
56 if (small_const_nbits(size)) {
57 unsigned long val;
58
59 if (unlikely(offset >= size))
60 return size;
61
62 val = *addr1 & *addr2 & GENMASK(size - 1, offset);
63 return val ? __ffs(val) : size;
64 }
65
66 return _find_next_bit(addr1, addr2, size, offset, 0UL, 0);
67}
68#endif
69
70#ifndef find_next_zero_bit
71/**
72 * find_next_zero_bit - find the next cleared bit in a memory region
73 * @addr: The address to base the search on
74 * @offset: The bitnumber to start searching at
75 * @size: The bitmap size in bits
76 *
77 * Returns the bit number of the next zero bit
78 * If no bits are zero, returns @size.
79 */
80static inline
81unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
82 unsigned long offset)
83{
84 if (small_const_nbits(size)) {
85 unsigned long val;
86
87 if (unlikely(offset >= size))
88 return size;
89
90 val = *addr | ~GENMASK(size - 1, offset);
91 return val == ~0UL ? size : ffz(val);
92 }
93
94 return _find_next_bit(addr, NULL, size, offset, ~0UL, 0);
95}
96#endif
97
98#ifdef CONFIG_GENERIC_FIND_FIRST_BIT
99
100/**
101 * find_first_bit - find the first set bit in a memory region
102 * @addr: The address to start the search at
103 * @size: The maximum number of bits to search
104 *
105 * Returns the bit number of the first set bit.
106 * If no bits are set, returns @size.
107 */
108static inline
109unsigned long find_first_bit(const unsigned long *addr, unsigned long size)
110{
111 if (small_const_nbits(size)) {
112 unsigned long val = *addr & GENMASK(size - 1, 0);
113
114 return val ? __ffs(val) : size;
115 }
116
117 return _find_first_bit(addr, size);
118}
119
120/**
121 * find_first_zero_bit - find the first cleared bit in a memory region
122 * @addr: The address to start the search at
123 * @size: The maximum number of bits to search
124 *
125 * Returns the bit number of the first cleared bit.
126 * If no bits are zero, returns @size.
127 */
128static inline
129unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size)
130{
131 if (small_const_nbits(size)) {
132 unsigned long val = *addr | ~GENMASK(size - 1, 0);
133
134 return val == ~0UL ? size : ffz(val);
135 }
136
137 return _find_first_zero_bit(addr, size);
138}
139#else /* CONFIG_GENERIC_FIND_FIRST_BIT */
140
141#ifndef find_first_bit
142#define find_first_bit(addr, size) find_next_bit((addr), (size), 0)
143#endif
144#ifndef find_first_zero_bit
145#define find_first_zero_bit(addr, size) find_next_zero_bit((addr), (size), 0)
146#endif
147
148#endif /* CONFIG_GENERIC_FIND_FIRST_BIT */
149
150#ifndef find_last_bit
151/**
152 * find_last_bit - find the last set bit in a memory region
153 * @addr: The address to start the search at
154 * @size: The number of bits to search
155 *
156 * Returns the bit number of the last set bit, or size.
157 */
158static inline
159unsigned long find_last_bit(const unsigned long *addr, unsigned long size)
160{
161 if (small_const_nbits(size)) {
162 unsigned long val = *addr & GENMASK(size - 1, 0);
163
164 return val ? __fls(val) : size;
165 }
166
167 return _find_last_bit(addr, size);
168}
169#endif
170
171/**
172 * find_next_clump8 - find next 8-bit clump with set bits in a memory region
173 * @clump: location to store copy of found clump
174 * @addr: address to base the search on
175 * @size: bitmap size in number of bits
176 * @offset: bit offset at which to start searching
177 *
178 * Returns the bit offset for the next set clump; the found clump value is
179 * copied to the location pointed by @clump. If no bits are set, returns @size.
180 */
181extern unsigned long find_next_clump8(unsigned long *clump,
182 const unsigned long *addr,
183 unsigned long size, unsigned long offset);
184
185#define find_first_clump8(clump, bits, size) \
186 find_next_clump8((clump), (bits), (size), 0)
187
188#endif /*_ASM_GENERIC_BITOPS_FIND_H_ */