-extern int mbcs_open(struct inode *ip, struct file *fp);
-extern ssize_t mbcs_sram_read(struct file *fp, char __user *buf, size_t len,
+static int mbcs_open(struct inode *ip, struct file *fp);
+static ssize_t mbcs_sram_read(struct file *fp, char __user *buf, size_t len,