percpu.h revision c559cd81139f97cecad1ad91a0b2e25a5936d53
1c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#ifndef __LINUX_PERCPU_H 2c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#define __LINUX_PERCPU_H 3c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#include <linux/spinlock.h> /* For preempt_disable() */ 4c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#include <linux/slab.h> /* For kmalloc() */ 5c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#include <linux/smp.h> 6c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#include <linux/string.h> /* For memset() */ 7c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#include <asm/percpu.h> 8c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 9c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru/* Enough to cover all DEFINE_PER_CPUs in kernel, including modules. */ 10c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#ifndef PERCPU_ENOUGH_ROOM 11c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#define PERCPU_ENOUGH_ROOM 32768 12c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#endif 13c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 14c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru/* Must be an lvalue. */ 15c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#define get_cpu_var(var) (*({ preempt_disable(); &__get_cpu_var(var); })) 16c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#define put_cpu_var(var) preempt_enable() 17c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 18c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#ifdef CONFIG_SMP 19c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 20c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Querustruct percpu_data { 21c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru void *ptrs[NR_CPUS]; 22c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru}; 23c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 24c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru/* 25c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Use this to get to a cpu's version of the per-cpu object allocated using 26c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * alloc_percpu. Non-atomic access to the current CPU's version should 27c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * probably be combined with get_cpu()/put_cpu(). 28c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru */ 29c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#define per_cpu_ptr(ptr, cpu) \ 30c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru({ \ 31c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru struct percpu_data *__p = (struct percpu_data *)~(unsigned long)(ptr); \ 32c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru (__typeof__(ptr))__p->ptrs[(cpu)]; \ 33c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru}) 34c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 35c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queruextern void *__alloc_percpu(size_t size); 36c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queruextern void free_percpu(const void *); 37c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 38c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#else /* CONFIG_SMP */ 39c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 40c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); }) 41c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 42c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Querustatic inline void *__alloc_percpu(size_t size) 43c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru{ 44c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru void *ret = kmalloc(size, GFP_KERNEL); 45c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru if (ret) 46c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru memset(ret, 0, size); 47c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru return ret; 48c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru} 49c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Querustatic inline void free_percpu(const void *ptr) 50c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru{ 51c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru kfree(ptr); 52c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru} 53c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 54c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#endif /* CONFIG_SMP */ 55c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 56c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru/* Simple wrapper for the common case: zeros memory. */ 57c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#define alloc_percpu(type) ((type *)(__alloc_percpu(sizeof(type)))) 58c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 59c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#endif /* __LINUX_PERCPU_H */ 60