tty_io: Use kzalloc

Also remove needless casts.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/char/tty_io.c

@@ -2033,11 +2033,9 @@ static int init_dev(struct tty_driver *driver, int idx,
 	}
 
 	if (!*ltp_loc) {
-		ltp = (struct ktermios *) kmalloc(sizeof(struct ktermios),
-						 GFP_KERNEL);
+		ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
 		if (!ltp)
 			goto free_mem_out;
-		memset(ltp, 0, sizeof(struct ktermios));
 	}
 
 	if (driver->type == TTY_DRIVER_TYPE_PTY) {
@@ -2066,11 +2064,9 @@ static int init_dev(struct tty_driver *driver, int idx,
 		}
 
 		if (!*o_ltp_loc) {
-			o_ltp = (struct ktermios *)
-				kmalloc(sizeof(struct ktermios), GFP_KERNEL);
+			o_ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
 			if (!o_ltp)
 				goto free_mem_out;
-			memset(o_ltp, 0, sizeof(struct ktermios));
 		}
 
 		/*
@@ -3755,9 +3751,8 @@ struct tty_driver *alloc_tty_driver(int lines)
 {
 	struct tty_driver *driver;
 
-	driver = kmalloc(sizeof(struct tty_driver), GFP_KERNEL);
+	driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
 	if (driver) {
-		memset(driver, 0, sizeof(struct tty_driver));
 		driver->magic = TTY_DRIVER_MAGIC;
 		driver->num = lines;
 		/* later we'll move allocation of tables here */