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1da177e4 LT |
1 | #ifndef __LINUX_PERCPU_H |
2 | #define __LINUX_PERCPU_H | |
3 | #include <linux/spinlock.h> /* For preempt_disable() */ | |
4 | #include <linux/slab.h> /* For kmalloc() */ | |
5 | #include <linux/smp.h> | |
6 | #include <linux/string.h> /* For memset() */ | |
7 | #include <asm/percpu.h> | |
8 | ||
9 | /* Enough to cover all DEFINE_PER_CPUs in kernel, including modules. */ | |
10 | #ifndef PERCPU_ENOUGH_ROOM | |
11 | #define PERCPU_ENOUGH_ROOM 32768 | |
12 | #endif | |
13 | ||
14 | /* Must be an lvalue. */ | |
15 | #define get_cpu_var(var) (*({ preempt_disable(); &__get_cpu_var(var); })) | |
16 | #define put_cpu_var(var) preempt_enable() | |
17 | ||
18 | #ifdef CONFIG_SMP | |
19 | ||
20 | struct percpu_data { | |
21 | void *ptrs[NR_CPUS]; | |
1da177e4 LT |
22 | }; |
23 | ||
24 | /* | |
25 | * Use this to get to a cpu's version of the per-cpu object allocated using | |
26 | * alloc_percpu. Non-atomic access to the current CPU's version should | |
27 | * probably be combined with get_cpu()/put_cpu(). | |
28 | */ | |
29 | #define per_cpu_ptr(ptr, cpu) \ | |
30 | ({ \ | |
31 | struct percpu_data *__p = (struct percpu_data *)~(unsigned long)(ptr); \ | |
32 | (__typeof__(ptr))__p->ptrs[(cpu)]; \ | |
33 | }) | |
34 | ||
f9f75005 | 35 | extern void *__alloc_percpu(size_t size); |
1da177e4 LT |
36 | extern void free_percpu(const void *); |
37 | ||
38 | #else /* CONFIG_SMP */ | |
39 | ||
66341a90 | 40 | #define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); }) |
1da177e4 | 41 | |
f9f75005 | 42 | static inline void *__alloc_percpu(size_t size) |
1da177e4 LT |
43 | { |
44 | void *ret = kmalloc(size, GFP_KERNEL); | |
45 | if (ret) | |
46 | memset(ret, 0, size); | |
47 | return ret; | |
48 | } | |
49 | static inline void free_percpu(const void *ptr) | |
50 | { | |
51 | kfree(ptr); | |
52 | } | |
53 | ||
54 | #endif /* CONFIG_SMP */ | |
55 | ||
56 | /* Simple wrapper for the common case: zeros memory. */ | |
f9f75005 | 57 | #define alloc_percpu(type) ((type *)(__alloc_percpu(sizeof(type)))) |
1da177e4 LT |
58 | |
59 | #endif /* __LINUX_PERCPU_H */ |