--- a/drivers/net/ar2313/ar2313.c
+++ b/drivers/net/ar2313/ar2313.c
@@ -291,7 +291,7 @@
 	sp->mii_bus.write = mdiobus_write;
 	sp->mii_bus.reset = mdiobus_reset;
 	sp->mii_bus.name = "ar2313_eth_mii";
-	sp->mii_bus.id = 0;
+	snprintf(sp->mii_bus.id, MII_BUS_ID_SIZE, "0");
 	sp->mii_bus.irq = kmalloc(sizeof(int), GFP_KERNEL);
 	*sp->mii_bus.irq = PHY_POLL;
 
