drivers/char/mxser.c: check return value of

@@ -3127,8 +3139,17 @@ static int mxser_get_ISA_conf(int cap, s
 		hwconf->ports = 8;
 	else
 		hwconf->ports = 4;
-	request_region(hwconf->ioaddr[0], 8 * hwconf->ports, "mxser(IO)");
-	request_region(hwconf->vector, 1, "mxser(vector)");
+	if (!(request_region(hwconf->ioaddr[0], 8 * hwconf->ports, "mxser(IO)"))) {
+		printk(KERN_ERR "mxser: I/O ports already in use\n");
+		return -EIO;
+	}
+	
+	if (!(request_region(hwconf->vector, 1, "mxser(vector)"))) {
+		printk(KERN_ERR "mxser: I/O ports already in use\n");
+		release_region(hwconf->ioaddr[0], 8 * hwconf->ports);
+		return -EIO;
+	}
+				
 	return hwconf->ports;
 }