+extern struct file *shmem_file_setup(const char *name,
+ loff_t size, unsigned long flags);
+extern int shmem_zero_setup(struct vm_area_struct *);
+extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
+extern int shmem_unuse(swp_entry_t entry, struct page *page);
+extern void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff,
+ struct page **pagep, swp_entry_t *ent);