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author | Rich Felker <dalias@libc.org> | 2016-03-30 00:53:03 +0300 |
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committer | Rich Felker <dalias@libc.org> | 2016-03-30 00:53:03 +0300 |
commit | 16b02d711f4059b8338ef967064195b47cae65ea (patch) | |
tree | 6d3e0b7629210b56f8d6cfa39184c878d8a15367 /tools/testing/radix-tree/linux/bitops/non-atomic.h | |
parent | b15d53d009558d14c4f394a6d1fa2039c7f45c43 (diff) | |
parent | f55532a0c0b8bb6148f4e07853b876ef73bc69ca (diff) | |
download | linux-16b02d711f4059b8338ef967064195b47cae65ea.tar.xz |
Merge tag 'v4.6-rc1'
Linux 4.6-rc1
Diffstat (limited to 'tools/testing/radix-tree/linux/bitops/non-atomic.h')
-rw-r--r-- | tools/testing/radix-tree/linux/bitops/non-atomic.h | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/tools/testing/radix-tree/linux/bitops/non-atomic.h b/tools/testing/radix-tree/linux/bitops/non-atomic.h new file mode 100644 index 000000000000..46a825cf2ae1 --- /dev/null +++ b/tools/testing/radix-tree/linux/bitops/non-atomic.h @@ -0,0 +1,111 @@ +#ifndef _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ +#define _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ + +#include <asm/types.h> + +#define BITOP_MASK(nr) (1UL << ((nr) % BITS_PER_LONG)) +#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG) + +/** + * __set_bit - Set a bit in memory + * @nr: the bit to set + * @addr: the address to start counting from + * + * Unlike set_bit(), this function is non-atomic and may be reordered. + * If it's called on the same region of memory simultaneously, the effect + * may be that only one operation succeeds. + */ +static inline void __set_bit(int nr, volatile unsigned long *addr) +{ + unsigned long mask = BITOP_MASK(nr); + unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr); + + *p |= mask; +} + +static inline void __clear_bit(int nr, volatile unsigned long *addr) +{ + unsigned long mask = BITOP_MASK(nr); + unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr); + + *p &= ~mask; +} + +/** + * __change_bit - Toggle a bit in memory + * @nr: the bit to change + * @addr: the address to start counting from + * + * Unlike change_bit(), this function is non-atomic and may be reordered. + * If it's called on the same region of memory simultaneously, the effect + * may be that only one operation succeeds. + */ +static inline void __change_bit(int nr, volatile unsigned long *addr) +{ + unsigned long mask = BITOP_MASK(nr); + unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr); + + *p ^= mask; +} + +/** + * __test_and_set_bit - Set a bit and return its old value + * @nr: Bit to set + * @addr: Address to count from + * + * This operation is non-atomic and can be reordered. + * If two examples of this operation race, one can appear to succeed + * but actually fail. You must protect multiple accesses with a lock. + */ +static inline int __test_and_set_bit(int nr, volatile unsigned long *addr) +{ + unsigned long mask = BITOP_MASK(nr); + unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr); + unsigned long old = *p; + + *p = old | mask; + return (old & mask) != 0; +} + +/** + * __test_and_clear_bit - Clear a bit and return its old value + * @nr: Bit to clear + * @addr: Address to count from + * + * This operation is non-atomic and can be reordered. + * If two examples of this operation race, one can appear to succeed + * but actually fail. You must protect multiple accesses with a lock. + */ +static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr) +{ + unsigned long mask = BITOP_MASK(nr); + unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr); + unsigned long old = *p; + + *p = old & ~mask; + return (old & mask) != 0; +} + +/* WARNING: non atomic and it can be reordered! */ +static inline int __test_and_change_bit(int nr, + volatile unsigned long *addr) +{ + unsigned long mask = BITOP_MASK(nr); + unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr); + unsigned long old = *p; + + *p = old ^ mask; + return (old & mask) != 0; +} + +/** + * test_bit - Determine whether a bit is set + * @nr: bit number to test + * @addr: Address to start counting from + */ +static inline int test_bit(int nr, const volatile unsigned long *addr) +{ + return 1UL & (addr[BITOP_WORD(nr)] >> (nr & (BITS_PER_LONG-1))); +} + +#endif /* _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ */ |