net/sched: taprio: split segmentation logic from qdisc_enqueue()

The majority of the taprio_enqueue()'s function is spent doing TCP
segmentation, which doesn't look right to me. Compilers shouldn't have a
problem in inlining code no matter how we write it, so move the
segmentation logic to a separate function.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/sch_taprio.c

@@ -575,28 +575,10 @@ static int taprio_enqueue_one(struct sk_buff *skb, struct Qdisc *sch,
 	return qdisc_enqueue(skb, child, to_free);
 }
 
-/* Will not be called in the full offload case, since the TX queues are
- * attached to the Qdisc created using qdisc_create_dflt()
- */
-static int taprio_enqueue(struct sk_buff *skb, struct Qdisc *sch,
+static int taprio_enqueue_segmented(struct sk_buff *skb, struct Qdisc *sch,
+				    struct Qdisc *child,
 				    struct sk_buff **to_free)
 {
-	struct taprio_sched *q = qdisc_priv(sch);
-	struct Qdisc *child;
-	int queue;
-
-	queue = skb_get_queue_mapping(skb);
-
-	child = q->qdiscs[queue];
-	if (unlikely(!child))
-		return qdisc_drop(skb, sch, to_free);
-
-	/* Large packets might not be transmitted when the transmission duration
-	 * exceeds any configured interval. Therefore, segment the skb into
-	 * smaller chunks. Drivers with full offload are expected to handle
-	 * this in hardware.
-	 */
-	if (skb_is_gso(skb)) {
 	unsigned int slen = 0, numsegs = 0, len = qdisc_pkt_len(skb);
 	netdev_features_t features = netif_skb_features(skb);
 	struct sk_buff *segs, *nskb;
@@ -625,7 +607,31 @@ static int taprio_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 	consume_skb(skb);
 
 	return numsegs > 0 ? NET_XMIT_SUCCESS : NET_XMIT_DROP;
-	}
+}
+
+/* Will not be called in the full offload case, since the TX queues are
+ * attached to the Qdisc created using qdisc_create_dflt()
+ */
+static int taprio_enqueue(struct sk_buff *skb, struct Qdisc *sch,
+			  struct sk_buff **to_free)
+{
+	struct taprio_sched *q = qdisc_priv(sch);
+	struct Qdisc *child;
+	int queue;
+
+	queue = skb_get_queue_mapping(skb);
+
+	child = q->qdiscs[queue];
+	if (unlikely(!child))
+		return qdisc_drop(skb, sch, to_free);
+
+	/* Large packets might not be transmitted when the transmission duration
+	 * exceeds any configured interval. Therefore, segment the skb into
+	 * smaller chunks. Drivers with full offload are expected to handle
+	 * this in hardware.
+	 */
+	if (skb_is_gso(skb))
+		return taprio_enqueue_segmented(skb, sch, child, to_free);
 
 	return taprio_enqueue_one(skb, sch, child, to_free);
 }