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