Handle Mysql error in Stored Procedure

-- http://stackoverflow.com/questions/26760414/mysql-stored-procedure-return-value
-- handle errors in MySql Stored Proceeduer

CREATE DEFINER=`root`@`localhost` PROCEDURE `validar_egreso`(
IN codigo_producto VARCHAR(100),
IN cantidad INT,
OUT valido INT(11)
)
BEGIN
DECLARE EXIT HANDLER FOR SQLEXCEPTION
BEGIN
    GET DIAGNOSTICS CONDITION 1
    @p1 = RETURNED_SQLSTATE, @p2 = MESSAGE_TEXT;
    SELECT @p1, @p2;
END
DECLARE resta INT(11);
SET resta = 0;

SELECT (s.stock - cantidad) INTO resta
FROM stock AS s
WHERE codigo_producto = s.codigo;

IF (resta > s.stock_minimo) THEN
    SET valido = 1;
ELSE
    SET valido = -1;
END IF;
SELECT valido;
END