1 #ifndef _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
2 #define _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
3 
4 #include <asm/types.h>
5 
6 /**
7  * __set_bit - Set a bit in memory
8  * @nr: the bit to set
9  * @addr: the address to start counting from
10  *
11  * Unlike set_bit(), this function is non-atomic and may be reordered.
12  * If it's called on the same region of memory simultaneously, the effect
13  * may be that only one operation succeeds.
14  */
15 static inline void __set_bit(int nr, volatile unsigned long *addr)
16 {
17 	unsigned long mask = BIT_MASK(nr);
18 	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
19 
20 	*p  |= mask;
21 }
22 
23 static inline void __clear_bit(int nr, volatile unsigned long *addr)
24 {
25 	unsigned long mask = BIT_MASK(nr);
26 	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
27 
28 	*p &= ~mask;
29 }
30 
31 /**
32  * __change_bit - Toggle a bit in memory
33  * @nr: the bit to change
34  * @addr: the address to start counting from
35  *
36  * Unlike change_bit(), this function is non-atomic and may be reordered.
37  * If it's called on the same region of memory simultaneously, the effect
38  * may be that only one operation succeeds.
39  */
40 static inline void __change_bit(int nr, volatile unsigned long *addr)
41 {
42 	unsigned long mask = BIT_MASK(nr);
43 	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
44 
45 	*p ^= mask;
46 }
47 
48 /**
49  * __test_and_set_bit - Set a bit and return its old value
50  * @nr: Bit to set
51  * @addr: Address to count from
52  *
53  * This operation is non-atomic and can be reordered.
54  * If two examples of this operation race, one can appear to succeed
55  * but actually fail.  You must protect multiple accesses with a lock.
56  */
57 static inline int __test_and_set_bit(int nr, volatile unsigned long *addr)
58 {
59 	unsigned long mask = BIT_MASK(nr);
60 	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
61 	unsigned long old = *p;
62 
63 	*p = old | mask;
64 	return (old & mask) != 0;
65 }
66 
67 /**
68  * __test_and_clear_bit - Clear a bit and return its old value
69  * @nr: Bit to clear
70  * @addr: Address to count from
71  *
72  * This operation is non-atomic and can be reordered.
73  * If two examples of this operation race, one can appear to succeed
74  * but actually fail.  You must protect multiple accesses with a lock.
75  */
76 static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr)
77 {
78 	unsigned long mask = BIT_MASK(nr);
79 	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
80 	unsigned long old = *p;
81 
82 	*p = old & ~mask;
83 	return (old & mask) != 0;
84 }
85 
86 /* WARNING: non atomic and it can be reordered! */
87 static inline int __test_and_change_bit(int nr,
88 					    volatile unsigned long *addr)
89 {
90 	unsigned long mask = BIT_MASK(nr);
91 	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
92 	unsigned long old = *p;
93 
94 	*p = old ^ mask;
95 	return (old & mask) != 0;
96 }
97 
98 /**
99  * test_bit - Determine whether a bit is set
100  * @nr: bit number to test
101  * @addr: Address to start counting from
102  */
103 static inline int test_bit(int nr, const volatile unsigned long *addr)
104 {
105 	return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
106 }
107 
108 #endif /* _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ */
109