root/include/asm-generic/bitops/atomic.h

INCLUDED FROM

DEFINITIONS

1. set_bit
2. clear_bit
3. change_bit
4. test_and_set_bit
5. test_and_clear_bit
6. test_and_change_bit

   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 
  14 static 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 
  20 static 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 
  26 static 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 
  32 static 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 
  45 static 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 
  58 static 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 */