#ifndef _ASM_GENERIC_LOCAL_H #define _ASM_GENERIC_LOCAL_H #include <linux/config.h> #include <linux/percpu.h> #include <linux/hardirq.h> #include <asm/types.h> /* An unsigned long type for operations which are atomic for a single * CPU. Usually used in combination with per-cpu variables. */ #if BITS_PER_LONG == 32 /* Implement in terms of atomics. */ /* Don't use typedef: don't want them to be mixed with atomic_t's. */ typedef struct { atomic_t a; } local_t; #define LOCAL_INIT(i) { ATOMIC_INIT(i) } #define local_read(l) ((unsigned long)atomic_read(&(l)->a)) #define local_set(l,i) atomic_set((&(l)->a),(i)) #define local_inc(l) atomic_inc(&(l)->a) #define local_dec(l) atomic_dec(&(l)->a) #define local_add(i,l) atomic_add((i),(&(l)->a)) #define local_sub(i,l) atomic_sub((i),(&(l)->a)) /* Non-atomic variants, ie. preemption disabled and won't be touched * in interrupt, etc. Some archs can optimize this case well. */ #define __local_inc(l) local_set((l), local_read(l) + 1) #define __local_dec(l) local_set((l), local_read(l) - 1) #define __local_add(i,l) local_set((l), local_read(l) + (i)) #define __local_sub(i,l) local_set((l), local_read(l) - (i)) #else /* ... can't use atomics. */ /* Implement in terms of three variables. Another option would be to use local_irq_save/restore. */ typedef struct { /* 0 = in hardirq, 1 = in softirq, 2 = usermode. */ unsigned long v[3]; } local_t; #define _LOCAL_VAR(l) ((l)->v[!in_interrupt() + !in_irq()]) #define LOCAL_INIT(i) { { (i), 0, 0 } } static inline unsigned long local_read(local_t *l) { return l->v[0] + l->v[1] + l->v[2]; } static inline void local_set(local_t *l, unsigned long v) { l->v[0] = v; l->v[1] = l->v[2] = 0; } static inline void local_inc(local_t *l) { preempt_disable(); _LOCAL_VAR(l)++; preempt_enable(); } static inline void local_dec(local_t *l) { preempt_disable(); _LOCAL_VAR(l)--; preempt_enable(); } static inline void local_add(unsigned long v, local_t *l) { preempt_disable(); _LOCAL_VAR(l) += v; preempt_enable(); } static inline void local_sub(unsigned long v, local_t *l) { preempt_disable(); _LOCAL_VAR(l) -= v; preempt_enable(); } /* Non-atomic variants, ie. preemption disabled and won't be touched * in interrupt, etc. Some archs can optimize this case well. */ #define __local_inc(l) ((l)->v[0]++) #define __local_dec(l) ((l)->v[0]--) #define __local_add(i,l) ((l)->v[0] += (i)) #define __local_sub(i,l) ((l)->v[0] -= (i)) #endif /* Non-atomic implementation */ /* Use these for per-cpu local_t variables: on some archs they are * much more efficient than these naive implementations. Note they take * a variable (eg. mystruct.foo), not an address. */ #define cpu_local_read(v) local_read(&__get_cpu_var(v)) #define cpu_local_set(v, i) local_set(&__get_cpu_var(v), (i)) #define cpu_local_inc(v) local_inc(&__get_cpu_var(v)) #define cpu_local_dec(v) local_dec(&__get_cpu_var(v)) #define cpu_local_add(i, v) local_add((i), &__get_cpu_var(v)) #define cpu_local_sub(i, v) local_sub((i), &__get_cpu_var(v)) /* Non-atomic increments, ie. preemption disabled and won't be touched * in interrupt, etc. Some archs can optimize this case well. */ #define __cpu_local_inc(v) __local_inc(&__get_cpu_var(v)) #define __cpu_local_dec(v) __local_dec(&__get_cpu_var(v)) #define __cpu_local_add(i, v) __local_add((i), &__get_cpu_var(v)) #define __cpu_local_sub(i, v) __local_sub((i), &__get_cpu_var(v)) #endif /* _ASM_GENERIC_LOCAL_H */