extern unsigned long __do_user_copy(void *to, const void *from, int n,
void **fault_addr, void **fault_catcher,
void (*op)(void *to, const void *from,
extern unsigned long __do_user_copy(void *to, const void *from, int n,
void **fault_addr, void **fault_catcher,
void (*op)(void *to, const void *from,