62 lines
2.4 KiB
C
62 lines
2.4 KiB
C
#ifndef _ASM_GENERIC_LOCAL_H
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#define _ASM_GENERIC_LOCAL_H
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#include <linux/percpu.h>
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#include <linux/hardirq.h>
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#include <asm/atomic.h>
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#include <asm/types.h>
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/*
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* A signed long type for operations which are atomic for a single CPU.
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* Usually used in combination with per-cpu variables.
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*
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* This is the default implementation, which uses atomic_long_t. Which is
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* rather pointless. The whole point behind local_t is that some processors
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* can perform atomic adds and subtracts in a manner which is atomic wrt IRQs
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* running on this CPU. local_t allows exploitation of such capabilities.
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*/
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/* Implement in terms of atomics. */
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/* Don't use typedef: don't want them to be mixed with atomic_t's. */
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typedef struct
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{
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atomic_long_t a;
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} local_t;
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#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
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#define local_read(l) atomic_long_read(&(l)->a)
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#define local_set(l,i) atomic_long_set((&(l)->a),(i))
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#define local_inc(l) atomic_long_inc(&(l)->a)
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#define local_dec(l) atomic_long_dec(&(l)->a)
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#define local_add(i,l) atomic_long_add((i),(&(l)->a))
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#define local_sub(i,l) atomic_long_sub((i),(&(l)->a))
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/* Non-atomic variants, ie. preemption disabled and won't be touched
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* in interrupt, etc. Some archs can optimize this case well. */
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#define __local_inc(l) local_set((l), local_read(l) + 1)
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#define __local_dec(l) local_set((l), local_read(l) - 1)
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#define __local_add(i,l) local_set((l), local_read(l) + (i))
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#define __local_sub(i,l) local_set((l), local_read(l) - (i))
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/* Use these for per-cpu local_t variables: on some archs they are
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* much more efficient than these naive implementations. Note they take
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* a variable (eg. mystruct.foo), not an address.
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*/
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#define cpu_local_read(v) local_read(&__get_cpu_var(v))
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#define cpu_local_set(v, i) local_set(&__get_cpu_var(v), (i))
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#define cpu_local_inc(v) local_inc(&__get_cpu_var(v))
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#define cpu_local_dec(v) local_dec(&__get_cpu_var(v))
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#define cpu_local_add(i, v) local_add((i), &__get_cpu_var(v))
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#define cpu_local_sub(i, v) local_sub((i), &__get_cpu_var(v))
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/* Non-atomic increments, ie. preemption disabled and won't be touched
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* in interrupt, etc. Some archs can optimize this case well.
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*/
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#define __cpu_local_inc(v) __local_inc(&__get_cpu_var(v))
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#define __cpu_local_dec(v) __local_dec(&__get_cpu_var(v))
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#define __cpu_local_add(i, v) __local_add((i), &__get_cpu_var(v))
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#define __cpu_local_sub(i, v) __local_sub((i), &__get_cpu_var(v))
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#endif /* _ASM_GENERIC_LOCAL_H */
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