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1#ifndef _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
2#define _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
3
4#include <linux/types.h>
5
6#define BITOP_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
7#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG)
8
9/**
10 * __set_bit - Set a bit in memory
11 * @nr: the bit to set
12 * @addr: the address to start counting from
13 *
14 * Unlike set_bit(), this function is non-atomic and may be reordered.
15 * If it's called on the same region of memory simultaneously, the effect
16 * may be that only one operation succeeds.
17 */
18static inline void __set_bit(int nr, volatile unsigned long *addr)
19{
20 unsigned long mask = BITOP_MASK(nr);
21 unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
22
23 *p |= mask;
24}
25
26static inline void __clear_bit(int nr, volatile unsigned long *addr)
27{
28 unsigned long mask = BITOP_MASK(nr);
29 unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
30
31 *p &= ~mask;
32}
33
34/**
35 * __change_bit - Toggle a bit in memory
36 * @nr: the bit to change
37 * @addr: the address to start counting from
38 *
39 * Unlike change_bit(), this function is non-atomic and may be reordered.
40 * If it's called on the same region of memory simultaneously, the effect
41 * may be that only one operation succeeds.
42 */
43static inline void __change_bit(int nr, volatile unsigned long *addr)
44{
45 unsigned long mask = BITOP_MASK(nr);
46 unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
47
48 *p ^= mask;
49}
50
51/**
52 * __test_and_set_bit - Set a bit and return its old value
53 * @nr: Bit to set
54 * @addr: Address to count from
55 *
56 * This operation is non-atomic and can be reordered.
57 * If two examples of this operation race, one can appear to succeed
58 * but actually fail. You must protect multiple accesses with a lock.
59 */
60static inline int __test_and_set_bit(int nr, volatile unsigned long *addr)
61{
62 unsigned long mask = BITOP_MASK(nr);
63 unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
64 unsigned long old = *p;
65
66 *p = old | mask;
67 return (old & mask) != 0;
68}
69
70/**
71 * __test_and_clear_bit - Clear a bit and return its old value
72 * @nr: Bit to clear
73 * @addr: Address to count from
74 *
75 * This operation is non-atomic and can be reordered.
76 * If two examples of this operation race, one can appear to succeed
77 * but actually fail. You must protect multiple accesses with a lock.
78 */
79static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr)
80{
81 unsigned long mask = BITOP_MASK(nr);
82 unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
83 unsigned long old = *p;
84
85 *p = old & ~mask;
86 return (old & mask) != 0;
87}
88
89/* WARNING: non atomic and it can be reordered! */
90static inline int __test_and_change_bit(int nr,
91 volatile unsigned long *addr)
92{
93 unsigned long mask = BITOP_MASK(nr);
94 unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
95 unsigned long old = *p;
96
97 *p = old ^ mask;
98 return (old & mask) != 0;
99}
100
101/**
102 * test_bit - Determine whether a bit is set
103 * @nr: bit number to test
104 * @addr: Address to start counting from
105 */
106static inline int test_bit(int nr, const volatile unsigned long *addr)
107{
108 return 1UL & (addr[BITOP_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
109}
110
111/**
112 * __ffs - find first bit in word.
113 * @word: The word to search
114 *
115 * Undefined if no bit exists, so code should check against 0 first.
116 */
117static inline unsigned long __ffs(unsigned long word)
118{
119 int num = 0;
120
121 if ((word & 0xffffffff) == 0) {
122 num += 32;
123 word >>= 32;
124 }
125 if ((word & 0xffff) == 0) {
126 num += 16;
127 word >>= 16;
128 }
129 if ((word & 0xff) == 0) {
130 num += 8;
131 word >>= 8;
132 }
133 if ((word & 0xf) == 0) {
134 num += 4;
135 word >>= 4;
136 }
137 if ((word & 0x3) == 0) {
138 num += 2;
139 word >>= 2;
140 }
141 if ((word & 0x1) == 0)
142 num += 1;
143 return num;
144}
145
146unsigned long find_next_bit(const unsigned long *addr,
147 unsigned long size,
148 unsigned long offset);
149
150#endif /* _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ */