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 20struct percpu_data { 21 void *ptrs[NR_CPUS]; 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 35extern void *__alloc_percpu(size_t size); 36extern void free_percpu(const void *); 37 38#else /* CONFIG_SMP */ 39 40#define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); }) 41 42static inline void *__alloc_percpu(size_t size) 43{ 44 void *ret = kmalloc(size, GFP_KERNEL); 45 if (ret) 46 memset(ret, 0, size); 47 return ret; 48} 49static 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. */ 57#define alloc_percpu(type) ((type *)(__alloc_percpu(sizeof(type)))) 58 59#endif /* __LINUX_PERCPU_H */ 60