1 #ifndef _ASM_GENERIC_LOCAL_H 2 #define _ASM_GENERIC_LOCAL_H 3 4 #include <linux/percpu.h> 5 #include <linux/hardirq.h> 6 #include <asm/atomic.h> 7 #include <asm/types.h> 8 9 /* 10 * A signed long type for operations which are atomic for a single CPU. 11 * Usually used in combination with per-cpu variables. 12 * 13 * This is the default implementation, which uses atomic_long_t. Which is 14 * rather pointless. The whole point behind local_t is that some processors 15 * can perform atomic adds and subtracts in a manner which is atomic wrt IRQs 16 * running on this CPU. local_t allows exploitation of such capabilities. 17 */ 18 19 /* Implement in terms of atomics. */ 20 21 /* Don't use typedef: don't want them to be mixed with atomic_t's. */ 22 typedef struct 23 { 24 atomic_long_t a; 25 } local_t; 26 27 #define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) } 28 29 #define local_read(l) atomic_long_read(&(l)->a) 30 #define local_set(l,i) atomic_long_set((&(l)->a),(i)) 31 #define local_inc(l) atomic_long_inc(&(l)->a) 32 #define local_dec(l) atomic_long_dec(&(l)->a) 33 #define local_add(i,l) atomic_long_add((i),(&(l)->a)) 34 #define local_sub(i,l) atomic_long_sub((i),(&(l)->a)) 35 36 /* Non-atomic variants, ie. preemption disabled and won't be touched 37 * in interrupt, etc. Some archs can optimize this case well. */ 38 #define __local_inc(l) local_set((l), local_read(l) + 1) 39 #define __local_dec(l) local_set((l), local_read(l) - 1) 40 #define __local_add(i,l) local_set((l), local_read(l) + (i)) 41 #define __local_sub(i,l) local_set((l), local_read(l) - (i)) 42 43 /* Use these for per-cpu local_t variables: on some archs they are 44 * much more efficient than these naive implementations. Note they take 45 * a variable (eg. mystruct.foo), not an address. 46 */ 47 #define cpu_local_read(v) local_read(&__get_cpu_var(v)) 48 #define cpu_local_set(v, i) local_set(&__get_cpu_var(v), (i)) 49 #define cpu_local_inc(v) local_inc(&__get_cpu_var(v)) 50 #define cpu_local_dec(v) local_dec(&__get_cpu_var(v)) 51 #define cpu_local_add(i, v) local_add((i), &__get_cpu_var(v)) 52 #define cpu_local_sub(i, v) local_sub((i), &__get_cpu_var(v)) 53 54 /* Non-atomic increments, ie. preemption disabled and won't be touched 55 * in interrupt, etc. Some archs can optimize this case well. 56 */ 57 #define __cpu_local_inc(v) __local_inc(&__get_cpu_var(v)) 58 #define __cpu_local_dec(v) __local_dec(&__get_cpu_var(v)) 59 #define __cpu_local_add(i, v) __local_add((i), &__get_cpu_var(v)) 60 #define __cpu_local_sub(i, v) __local_sub((i), &__get_cpu_var(v)) 61 62 #endif /* _ASM_GENERIC_LOCAL_H */ 63
