119 lines
3.4 KiB
C
119 lines
3.4 KiB
C
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#ifndef _ASM_GENERIC_LOCAL_H
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#define _ASM_GENERIC_LOCAL_H
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#include <linux/config.h>
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#include <linux/percpu.h>
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#include <linux/hardirq.h>
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#include <asm/types.h>
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/* An unsigned long type for operations which are atomic for a single
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* CPU. Usually used in combination with per-cpu variables. */
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#if BITS_PER_LONG == 32
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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_t a;
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} local_t;
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#define LOCAL_INIT(i) { ATOMIC_INIT(i) }
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#define local_read(l) ((unsigned long)atomic_read(&(l)->a))
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#define local_set(l,i) atomic_set((&(l)->a),(i))
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#define local_inc(l) atomic_inc(&(l)->a)
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#define local_dec(l) atomic_dec(&(l)->a)
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#define local_add(i,l) atomic_add((i),(&(l)->a))
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#define local_sub(i,l) atomic_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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#else /* ... can't use atomics. */
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/* Implement in terms of three variables.
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Another option would be to use local_irq_save/restore. */
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typedef struct
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{
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/* 0 = in hardirq, 1 = in softirq, 2 = usermode. */
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unsigned long v[3];
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} local_t;
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#define _LOCAL_VAR(l) ((l)->v[!in_interrupt() + !in_irq()])
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#define LOCAL_INIT(i) { { (i), 0, 0 } }
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static inline unsigned long local_read(local_t *l)
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{
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return l->v[0] + l->v[1] + l->v[2];
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}
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static inline void local_set(local_t *l, unsigned long v)
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{
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l->v[0] = v;
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l->v[1] = l->v[2] = 0;
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}
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static inline void local_inc(local_t *l)
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{
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preempt_disable();
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_LOCAL_VAR(l)++;
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preempt_enable();
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}
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static inline void local_dec(local_t *l)
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{
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preempt_disable();
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_LOCAL_VAR(l)--;
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preempt_enable();
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}
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static inline void local_add(unsigned long v, local_t *l)
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{
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preempt_disable();
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_LOCAL_VAR(l) += v;
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preempt_enable();
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}
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static inline void local_sub(unsigned long v, local_t *l)
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{
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preempt_disable();
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_LOCAL_VAR(l) -= v;
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preempt_enable();
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}
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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) ((l)->v[0]++)
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#define __local_dec(l) ((l)->v[0]--)
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#define __local_add(i,l) ((l)->v[0] += (i))
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#define __local_sub(i,l) ((l)->v[0] -= (i))
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#endif /* Non-atomic implementation */
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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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