| 1 |
|
| 2 | #ifndef _LINUX_ATOMIC_H
|
| 3 | #define _LINUX_ATOMIC_H
|
| 4 | #include <asm/atomic.h>
|
| 5 |
|
| 6 | |
| 7 | * Provide __deprecated wrappers for the new interface, avoid flag day changes.
|
| 8 | * We need the ugly external functions to break header recursion hell.
|
| 9 |
|
| 10 | #ifndef smp_mb__before_atomic_inc
|
| 11 | static inline void __deprecated smp_mb__before_atomic_inc(void)
|
| 12 | {
|
| 13 | extern void __smp_mb__before_atomic(void);
|
| 14 | __smp_mb__before_atomic();
|
| 15 | }
|
| 16 | #endif
|
| 17 |
|
| 18 | #ifndef smp_mb__after_atomic_inc
|
| 19 | static inline void __deprecated smp_mb__after_atomic_inc(void)
|
| 20 | {
|
| 21 | extern void __smp_mb__after_atomic(void);
|
| 22 | __smp_mb__after_atomic();
|
| 23 | }
|
| 24 | #endif
|
| 25 |
|
| 26 | #ifndef smp_mb__before_atomic_dec
|
| 27 | static inline void __deprecated smp_mb__before_atomic_dec(void)
|
| 28 | {
|
| 29 | extern void __smp_mb__before_atomic(void);
|
| 30 | __smp_mb__before_atomic();
|
| 31 | }
|
| 32 | #endif
|
| 33 |
|
| 34 | #ifndef smp_mb__after_atomic_dec
|
| 35 | static inline void __deprecated smp_mb__after_atomic_dec(void)
|
| 36 | {
|
| 37 | extern void __smp_mb__after_atomic(void);
|
| 38 | __smp_mb__after_atomic();
|
| 39 | }
|
| 40 | #endif
|
| 41 |
|
| 42 | |
| 43 | * atomic_add_unless - add unless the number is already a given value
|
| 44 | * @v: pointer of type atomic_t
|
| 45 | * @a: the amount to add to v...
|
| 46 | * @u: ...unless v is equal to u.
|
| 47 | *
|
| 48 | * Atomically adds @a to @v, so long as @v was not already @u.
|
| 49 | * Returns non-zero if @v was not @u, and zero otherwise.
|
| 50 |
|
| 51 | static inline int atomic_add_unless(atomic_t *v, int a, int u)
|
| 52 | {
|
| 53 | return __atomic_add_unless(v, a, u) != u;
|
| 54 | }
|
| 55 |
|
| 56 | |
| 57 | * atomic_inc_not_zero - increment unless the number is zero
|
| 58 | * @v: pointer of type atomic_t
|
| 59 | *
|
| 60 | * Atomically increments @v by 1, so long as @v is non-zero.
|
| 61 | * Returns non-zero if @v was non-zero, and zero otherwise.
|
| 62 |
|
| 63 | #ifndef atomic_inc_not_zero
|
| 64 | #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
|
| 65 | #endif
|
| 66 |
|
| 67 | |
| 68 | * atomic_inc_not_zero_hint - increment if not null
|
| 69 | * @v: pointer of type atomic_t
|
| 70 | * @hint: probable value of the atomic before the increment
|
| 71 | *
|
| 72 | * This version of atomic_inc_not_zero() gives a hint of probable
|
| 73 | * value of the atomic. This helps processor to not read the memory
|
| 74 | * before doing the atomic read/modify/write cycle, lowering
|
| 75 | * number of bus transactions on some arches.
|
| 76 | *
|
| 77 | * Returns: 0 if increment was not done, 1 otherwise.
|
| 78 |
|
| 79 | #ifndef atomic_inc_not_zero_hint
|
| 80 | static inline int atomic_inc_not_zero_hint(atomic_t *v, int hint)
|
| 81 | {
|
| 82 | int val, c = hint;
|
| 83 |
|
| 84 |
|
| 85 | if (!hint)
|
| 86 | return atomic_inc_not_zero(v);
|
| 87 |
|
| 88 | do {
|
| 89 | val = atomic_cmpxchg(v, c, c + 1);
|
| 90 | if (val == c)
|
| 91 | return 1;
|
| 92 | c = val;
|
| 93 | } while (c);
|
| 94 |
|
| 95 | return 0;
|
| 96 | }
|
| 97 | #endif
|
| 98 |
|
| 99 | #ifndef atomic_inc_unless_negative
|
| 100 | static inline int atomic_inc_unless_negative(atomic_t *p)
|
| 101 | {
|
| 102 | int v, v1;
|
| 103 | for (v = 0; v >= 0; v = v1) {
|
| 104 | v1 = atomic_cmpxchg(p, v, v + 1);
|
| 105 | if (likely(v1 == v))
|
| 106 | return 1;
|
| 107 | }
|
| 108 | return 0;
|
| 109 | }
|
| 110 | #endif
|
| 111 |
|
| 112 | #ifndef atomic_dec_unless_positive
|
| 113 | static inline int atomic_dec_unless_positive(atomic_t *p)
|
| 114 | {
|
| 115 | int v, v1;
|
| 116 | for (v = 0; v <= 0; v = v1) {
|
| 117 | v1 = atomic_cmpxchg(p, v, v - 1);
|
| 118 | if (likely(v1 == v))
|
| 119 | return 1;
|
| 120 | }
|
| 121 | return 0;
|
| 122 | }
|
| 123 | #endif
|
| 124 |
|
| 125 | |
| 126 | * atomic_dec_if_positive - decrement by 1 if old value positive
|
| 127 | * @v: pointer of type atomic_t
|
| 128 | *
|
| 129 | * The function returns the old value of *v minus 1, even if
|
| 130 | * the atomic variable, v, was not decremented.
|
| 131 |
|
| 132 | #ifndef atomic_dec_if_positive
|
| 133 | static inline int atomic_dec_if_positive(atomic_t *v)
|
| 134 | {
|
| 135 | int c, old, dec;
|
| 136 | c = atomic_read(v);
|
| 137 | for (;;) {
|
| 138 | dec = c - 1;
|
| 139 | if (unlikely(dec < 0))
|
| 140 | break;
|
| 141 | old = atomic_cmpxchg((v), c, dec);
|
| 142 | if (likely(old == c))
|
| 143 | break;
|
| 144 | c = old;
|
| 145 | }
|
| 146 | return dec;
|
| 147 | }
|
| 148 | #endif
|
| 149 |
|
| 150 | #ifndef CONFIG_ARCH_HAS_ATOMIC_OR
|
| 151 | static inline void atomic_or(int i, atomic_t *v)
|
| 152 | {
|
| 153 | int old;
|
| 154 | int new;
|
| 155 |
|
| 156 | do {
|
| 157 | old = atomic_read(v);
|
| 158 | new = old | i;
|
| 159 | } while (atomic_cmpxchg(v, old, new) != old);
|
| 160 | }
|
| 161 | #endif
|
| 162 |
|
| 163 | #include <asm-generic/atomic-long.h>
|
| 164 | #ifdef CONFIG_GENERIC_ATOMIC64
|
| 165 | #include <asm-generic/atomic64.h>
|
| 166 | #endif
|
| 167 | #endif
|