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Linux kernel mirror (for testing)
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kernel
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linux
1#ifndef _ASM_GENERIC_LOCAL_H
2#define _ASM_GENERIC_LOCAL_H
3
4#include <linux/config.h>
5#include <linux/percpu.h>
6#include <linux/hardirq.h>
7#include <asm/types.h>
8
9/* An unsigned long type for operations which are atomic for a single
10 * CPU. Usually used in combination with per-cpu variables. */
11
12#if BITS_PER_LONG == 32
13/* Implement in terms of atomics. */
14
15/* Don't use typedef: don't want them to be mixed with atomic_t's. */
16typedef struct
17{
18 atomic_t a;
19} local_t;
20
21#define LOCAL_INIT(i) { ATOMIC_INIT(i) }
22
23#define local_read(l) ((unsigned long)atomic_read(&(l)->a))
24#define local_set(l,i) atomic_set((&(l)->a),(i))
25#define local_inc(l) atomic_inc(&(l)->a)
26#define local_dec(l) atomic_dec(&(l)->a)
27#define local_add(i,l) atomic_add((i),(&(l)->a))
28#define local_sub(i,l) atomic_sub((i),(&(l)->a))
29
30/* Non-atomic variants, ie. preemption disabled and won't be touched
31 * in interrupt, etc. Some archs can optimize this case well. */
32#define __local_inc(l) local_set((l), local_read(l) + 1)
33#define __local_dec(l) local_set((l), local_read(l) - 1)
34#define __local_add(i,l) local_set((l), local_read(l) + (i))
35#define __local_sub(i,l) local_set((l), local_read(l) - (i))
36
37#else /* ... can't use atomics. */
38/* Implement in terms of three variables.
39 Another option would be to use local_irq_save/restore. */
40
41typedef struct
42{
43 /* 0 = in hardirq, 1 = in softirq, 2 = usermode. */
44 unsigned long v[3];
45} local_t;
46
47#define _LOCAL_VAR(l) ((l)->v[!in_interrupt() + !in_irq()])
48
49#define LOCAL_INIT(i) { { (i), 0, 0 } }
50
51static inline unsigned long local_read(local_t *l)
52{
53 return l->v[0] + l->v[1] + l->v[2];
54}
55
56static inline void local_set(local_t *l, unsigned long v)
57{
58 l->v[0] = v;
59 l->v[1] = l->v[2] = 0;
60}
61
62static inline void local_inc(local_t *l)
63{
64 preempt_disable();
65 _LOCAL_VAR(l)++;
66 preempt_enable();
67}
68
69static inline void local_dec(local_t *l)
70{
71 preempt_disable();
72 _LOCAL_VAR(l)--;
73 preempt_enable();
74}
75
76static inline void local_add(unsigned long v, local_t *l)
77{
78 preempt_disable();
79 _LOCAL_VAR(l) += v;
80 preempt_enable();
81}
82
83static inline void local_sub(unsigned long v, local_t *l)
84{
85 preempt_disable();
86 _LOCAL_VAR(l) -= v;
87 preempt_enable();
88}
89
90/* Non-atomic variants, ie. preemption disabled and won't be touched
91 * in interrupt, etc. Some archs can optimize this case well. */
92#define __local_inc(l) ((l)->v[0]++)
93#define __local_dec(l) ((l)->v[0]--)
94#define __local_add(i,l) ((l)->v[0] += (i))
95#define __local_sub(i,l) ((l)->v[0] -= (i))
96
97#endif /* Non-atomic implementation */
98
99/* Use these for per-cpu local_t variables: on some archs they are
100 * much more efficient than these naive implementations. Note they take
101 * a variable (eg. mystruct.foo), not an address.
102 */
103#define cpu_local_read(v) local_read(&__get_cpu_var(v))
104#define cpu_local_set(v, i) local_set(&__get_cpu_var(v), (i))
105#define cpu_local_inc(v) local_inc(&__get_cpu_var(v))
106#define cpu_local_dec(v) local_dec(&__get_cpu_var(v))
107#define cpu_local_add(i, v) local_add((i), &__get_cpu_var(v))
108#define cpu_local_sub(i, v) local_sub((i), &__get_cpu_var(v))
109
110/* Non-atomic increments, ie. preemption disabled and won't be touched
111 * in interrupt, etc. Some archs can optimize this case well.
112 */
113#define __cpu_local_inc(v) __local_inc(&__get_cpu_var(v))
114#define __cpu_local_dec(v) __local_dec(&__get_cpu_var(v))
115#define __cpu_local_add(i, v) __local_add((i), &__get_cpu_var(v))
116#define __cpu_local_sub(i, v) __local_sub((i), &__get_cpu_var(v))
117
118#endif /* _ASM_GENERIC_LOCAL_H */