| | 1 | #ifndef _ASM_GENERIC_LOCAL_H |
| | 2 | #define _ASM_GENERIC_LOCAL_H |
| | 3 | |
| | 4 | #include <linux/percpu.h> |
| | 5 | #include <asm/atomic.h> |
| | 6 | #include <asm/types.h> |
| | 7 | |
| | 8 | /* |
| | 9 | * A signed long type for operations which are atomic for a single CPU. |
| | 10 | * Usually used in combination with per-cpu variables. |
| | 11 | * |
| | 12 | * This is the default implementation, which uses atomic_long_t. Which is |
| | 13 | * rather pointless. The whole point behind local_t is that some processors |
| | 14 | * can perform atomic adds and subtracts in a manner which is atomic wrt IRQs |
| | 15 | * running on this CPU. local_t allows exploitation of such capabilities. |
| | 16 | */ |
| | 17 | |
| | 18 | /* Implement in terms of atomics. */ |
| | 19 | |
| | 20 | /* Don't use typedef: don't want them to be mixed with atomic_t's. */ |
| | 21 | typedef struct |
| | 22 | { |
| | 23 | atomic_long_t a; |
| | 24 | } local_t; |
| | 25 | |
| | 26 | #define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) } |
| | 27 | |
| | 28 | #define local_read(l) atomic_long_read(&(l)->a) |
| | 29 | #define local_set(l,i) atomic_long_set((&(l)->a),(i)) |
| | 30 | #define local_inc(l) atomic_long_inc(&(l)->a) |
| | 31 | #define local_dec(l) atomic_long_dec(&(l)->a) |
| | 32 | #define local_add(i,l) atomic_long_add((i),(&(l)->a)) |
| | 33 | #define local_sub(i,l) atomic_long_sub((i),(&(l)->a)) |
| | 34 | |
| | 35 | #define local_sub_and_test(i, l) atomic_long_sub_and_test((i), (&(l)->a)) |
| | 36 | #define local_dec_and_test(l) atomic_long_dec_and_test(&(l)->a) |
| | 37 | #define local_inc_and_test(l) atomic_long_inc_and_test(&(l)->a) |
| | 38 | #define local_add_negative(i, l) atomic_long_add_negative((i), (&(l)->a)) |
| | 39 | #define local_add_return(i, l) atomic_long_add_return((i), (&(l)->a)) |
| | 40 | #define local_sub_return(i, l) atomic_long_sub_return((i), (&(l)->a)) |
| | 41 | #define local_inc_return(l) atomic_long_inc_return(&(l)->a) |
| | 42 | |
| | 43 | #define local_cmpxchg(l, o, n) atomic_long_cmpxchg((&(l)->a), (o), (n)) |
| | 44 | #define local_xchg(l, n) atomic_long_xchg((&(l)->a), (n)) |
| | 45 | #define local_add_unless(l, _a, u) atomic_long_add_unless((&(l)->a), (_a), (u)) |
| | 46 | #define local_inc_not_zero(l) atomic_long_inc_not_zero(&(l)->a) |
| | 47 | |
| | 48 | /* Non-atomic variants, ie. preemption disabled and won't be touched |
| | 49 | * in interrupt, etc. Some archs can optimize this case well. */ |
| | 50 | #define __local_inc(l) local_set((l), local_read(l) + 1) |
| | 51 | #define __local_dec(l) local_set((l), local_read(l) - 1) |
| | 52 | #define __local_add(i,l) local_set((l), local_read(l) + (i)) |
| | 53 | #define __local_sub(i,l) local_set((l), local_read(l) - (i)) |
| | 54 | |
| | 55 | #endif /* _ASM_GENERIC_LOCAL_H */ |
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