diff --git a/include/linux/tty.h b/include/linux/tty.h
index f45cd74..f13f49a 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -24,6 +24,7 @@
 #include <linux/tty_driver.h>
 #include <linux/tty_ldisc.h>
 #include <linux/screen_info.h>
+#include <linux/mutex.h>
 
 #include <asm/system.h>
 
@@ -231,8 +232,8 @@
 	int canon_data;
 	unsigned long canon_head;
 	unsigned int canon_column;
-	struct semaphore atomic_read;
-	struct semaphore atomic_write;
+	struct mutex atomic_read_lock;
+	struct mutex atomic_write_lock;
 	unsigned char *write_buf;
 	int write_cnt;
 	spinlock_t read_lock;
@@ -319,8 +320,7 @@
 extern void tty_wakeup(struct tty_struct *tty);
 extern void tty_ldisc_flush(struct tty_struct *tty);
 
-struct semaphore;
-extern struct semaphore tty_sem;
+extern struct mutex tty_mutex;
 
 /* n_tty.c */
 extern struct tty_ldisc tty_ldisc_N_TTY;