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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]; | |
22 | void *blkp; | |
23 | }; | |
24 | ||
25 | /* | |
26 | * Use this to get to a cpu's version of the per-cpu object allocated using | |
27 | * alloc_percpu. Non-atomic access to the current CPU's version should | |
28 | * probably be combined with get_cpu()/put_cpu(). | |
29 | */ | |
30 | #define per_cpu_ptr(ptr, cpu) \ | |
31 | ({ \ | |
32 | struct percpu_data *__p = (struct percpu_data *)~(unsigned long)(ptr); \ | |
33 | (__typeof__(ptr))__p->ptrs[(cpu)]; \ | |
34 | }) | |
35 | ||
36 | extern void *__alloc_percpu(size_t size, size_t align); | |
37 | extern void free_percpu(const void *); | |
38 | ||
39 | #else /* CONFIG_SMP */ | |
40 | ||
41 | #define per_cpu_ptr(ptr, cpu) (ptr) | |
42 | ||
43 | static inline void *__alloc_percpu(size_t size, size_t align) | |
44 | { | |
45 | void *ret = kmalloc(size, GFP_KERNEL); | |
46 | if (ret) | |
47 | memset(ret, 0, size); | |
48 | return ret; | |
49 | } | |
50 | static inline void free_percpu(const void *ptr) | |
51 | { | |
52 | kfree(ptr); | |
53 | } | |
54 | ||
55 | #endif /* CONFIG_SMP */ | |
56 | ||
57 | /* Simple wrapper for the common case: zeros memory. */ | |
58 | #define alloc_percpu(type) \ | |
59 | ((type *)(__alloc_percpu(sizeof(type), __alignof__(type)))) | |
60 | ||
61 | #endif /* __LINUX_PERCPU_H */ |