diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 2ebe47b..81e7ccb 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -2230,8 +2230,7 @@
 
 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
 {
-	int ret, i;
-	int base = gsm->num << 6; /* Base for this MUX */
+	int ret, i, base;
 
 	gsm->tty = tty_kref_get(tty);
 	gsm->output = gsmld_output;
@@ -2241,6 +2240,7 @@
 	else {
 		/* Don't register device 0 - this is the control channel and not
 		   a usable tty interface */
+		base = gsm->num << 6; /* Base for this MUX */
 		for (i = 1; i < NUM_DLCI; i++)
 			tty_register_device(gsm_tty_driver, base + i, NULL);
 	}