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 */ 62