LXR linux/include/asm-generic/bitops/atomic.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _ASM_GENERIC_BITOPS_ATOMIC_H_
   3#define _ASM_GENERIC_BITOPS_ATOMIC_H_
   4
   5#include <linux/atomic.h>
   6#include <linux/compiler.h>
   7#include <asm/barrier.h>
   8
   9/*
  10 * Implementation of atomic bitops using atomic-fetch ops.
  11 * See Documentation/atomic_bitops.txt for details.
  12 */
  13
  14static __always_inline void set_bit(unsigned int nr, volatile unsigned long *p)
  15{
  16        p += BIT_WORD(nr);
  17        atomic_long_or(BIT_MASK(nr), (atomic_long_t *)p);
  18}
  19
  20static __always_inline void clear_bit(unsigned int nr, volatile unsigned long *p)
  21{
  22        p += BIT_WORD(nr);
  23        atomic_long_andnot(BIT_MASK(nr), (atomic_long_t *)p);
  24}
  25
  26static __always_inline void change_bit(unsigned int nr, volatile unsigned long *p)
  27{
  28        p += BIT_WORD(nr);
  29        atomic_long_xor(BIT_MASK(nr), (atomic_long_t *)p);
  30}
  31
  32static inline int test_and_set_bit(unsigned int nr, volatile unsigned long *p)
  33{
  34        long old;
  35        unsigned long mask = BIT_MASK(nr);
  36
  37        p += BIT_WORD(nr);
  38        if (READ_ONCE(*p) & mask)
  39                return 1;
  40
  41        old = atomic_long_fetch_or(mask, (atomic_long_t *)p);
  42        return !!(old & mask);
  43}
  44
  45static inline int test_and_clear_bit(unsigned int nr, volatile unsigned long *p)
  46{
  47        long old;
  48        unsigned long mask = BIT_MASK(nr);
  49
  50        p += BIT_WORD(nr);
  51        if (!(READ_ONCE(*p) & mask))
  52                return 0;
  53
  54        old = atomic_long_fetch_andnot(mask, (atomic_long_t *)p);
  55        return !!(old & mask);
  56}
  57
  58static inline int test_and_change_bit(unsigned int nr, volatile unsigned long *p)
  59{
  60        long old;
  61        unsigned long mask = BIT_MASK(nr);
  62
  63        p += BIT_WORD(nr);
  64        old = atomic_long_fetch_xor(mask, (atomic_long_t *)p);
  65        return !!(old & mask);
  66}
  67
  68#endif /* _ASM_GENERIC_BITOPS_ATOMIC_H */
  69