int shmem_lock(struct file *file, int lock, struct user_struct *user);
struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags);
-void shmem_set_file(struct vm_area_struct *vma, struct file *file);
int shmem_zero_setup(struct vm_area_struct *);
#ifndef CONFIG_MMU