1#ifndef _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ 2#define _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ 3 4#include <asm/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#endif /* _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ */ 112