net/sched: mqprio: refactor nlattr parsing to a separate function

mqprio_init() is quite large and unwieldy to add more code to.
Split the netlink attribute parsing to a dedicated function.
Signed-off-by: NVladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: NJacob Keller <jacob.e.keller@intel.com>
Reviewed-by: NSimon Horman <simon.horman@corigine.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sched/sch_mqprio.c

@@ -130,42 +130,14 @@ static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla,
 	return 0;
 }
 
-static int mqprio_init(struct Qdisc *sch, struct nlattr *opt,
-		       struct netlink_ext_ack *extack)
+static int mqprio_parse_nlattr(struct Qdisc *sch, struct tc_mqprio_qopt *qopt,
+			       struct nlattr *opt)
 {
-	struct net_device *dev = qdisc_dev(sch);
 	struct mqprio_sched *priv = qdisc_priv(sch);
-	struct netdev_queue *dev_queue;
-	struct Qdisc *qdisc;
-	int i, err = -EOPNOTSUPP;
-	struct tc_mqprio_qopt *qopt = NULL;
 	struct nlattr *tb[TCA_MQPRIO_MAX + 1];
 	struct nlattr *attr;
-	int rem;
-	int len;
-
-	BUILD_BUG_ON(TC_MAX_QUEUE != TC_QOPT_MAX_QUEUE);
-	BUILD_BUG_ON(TC_BITMASK != TC_QOPT_BITMASK);
-
-	if (sch->parent != TC_H_ROOT)
-		return -EOPNOTSUPP;
+	int i, rem, err;
 
-	if (!netif_is_multiqueue(dev))
-		return -EOPNOTSUPP;
-
-	/* make certain can allocate enough classids to handle queues */
-	if (dev->num_tx_queues >= TC_H_MIN_PRIORITY)
-		return -ENOMEM;
-
-	if (!opt || nla_len(opt) < sizeof(*qopt))
-		return -EINVAL;
-
-	qopt = nla_data(opt);
-	if (mqprio_parse_opt(dev, qopt))
-		return -EINVAL;
-
-	len = nla_len(opt) - NLA_ALIGN(sizeof(*qopt));
-	if (len > 0) {
 	err = parse_attr(tb, TCA_MQPRIO_MAX, opt, mqprio_policy,
 			 sizeof(*qopt));
 	if (err < 0)
@@ -215,6 +187,46 @@ static int mqprio_init(struct Qdisc *sch, struct nlattr *opt,
 		}
 		priv->flags |= TC_MQPRIO_F_MAX_RATE;
 	}
+
+	return 0;
+}
+
+static int mqprio_init(struct Qdisc *sch, struct nlattr *opt,
+		       struct netlink_ext_ack *extack)
+{
+	struct net_device *dev = qdisc_dev(sch);
+	struct mqprio_sched *priv = qdisc_priv(sch);
+	struct netdev_queue *dev_queue;
+	struct Qdisc *qdisc;
+	int i, err = -EOPNOTSUPP;
+	struct tc_mqprio_qopt *qopt = NULL;
+	int len;
+
+	BUILD_BUG_ON(TC_MAX_QUEUE != TC_QOPT_MAX_QUEUE);
+	BUILD_BUG_ON(TC_BITMASK != TC_QOPT_BITMASK);
+
+	if (sch->parent != TC_H_ROOT)
+		return -EOPNOTSUPP;
+
+	if (!netif_is_multiqueue(dev))
+		return -EOPNOTSUPP;
+
+	/* make certain can allocate enough classids to handle queues */
+	if (dev->num_tx_queues >= TC_H_MIN_PRIORITY)
+		return -ENOMEM;
+
+	if (!opt || nla_len(opt) < sizeof(*qopt))
+		return -EINVAL;
+
+	qopt = nla_data(opt);
+	if (mqprio_parse_opt(dev, qopt))
+		return -EINVAL;
+
+	len = nla_len(opt) - NLA_ALIGN(sizeof(*qopt));
+	if (len > 0) {
+		err = mqprio_parse_nlattr(sch, qopt, opt);
+		if (err)
+			return err;
 	}
 
 	/* pre-allocate qdisc, attachment can't fail */