[PATCH RFC net-next 15/19] net: dsa: tag_mtk: add GRO callbacks

[Alexander Lobakin]

Make GRO available for frames with MTK tag by adding the corresponding
callbacks to MTK tagger.

Signed-off-by: Alexander Lobakin <alobakin@xxxxxxxx>
---
 net/dsa/tag_mtk.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)

diff --git a/net/dsa/tag_mtk.c b/net/dsa/tag_mtk.c
index b926ffdf5fb5..13d929160283 100644
--- a/net/dsa/tag_mtk.c
+++ b/net/dsa/tag_mtk.c
@@ -102,12 +102,85 @@ static void mtk_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto,
 	*proto = mtk_tag_encap_proto(skb->data);
 }
 
+static struct sk_buff *mtk_tag_gro_receive(struct list_head *head,
+					   struct sk_buff *skb)
+{
+	const struct packet_offload *ptype;
+	struct sk_buff *p, *pp = NULL;
+	u32 data_off, data_end;
+	const u8 *data;
+	int flush = 1;
+
+	data_off = skb_gro_offset(skb);
+	data_end = data_off + MTK_HDR_LEN;
+
+	data = skb_gro_header_fast(skb, data_off);
+	if (skb_gro_header_hard(skb, data_end)) {
+		data = skb_gro_header_slow(skb, data_end, data_off);
+		if (unlikely(!data))
+			goto out;
+	}
+
+	rcu_read_lock();
+
+	ptype = gro_find_receive_by_type(mtk_tag_encap_proto(data));
+	if (!ptype)
+		goto out_unlock;
+
+	flush = 0;
+
+	list_for_each_entry(p, head, list) {
+		if (!NAPI_GRO_CB(p)->same_flow)
+			continue;
+
+		/* Data that is to the left to the current position is already
+		 * pulled to the head
+		 */
+		if (mtk_tag_source_port(skb->data + data_off) ^
+		    mtk_tag_source_port(p->data + data_off))
+			NAPI_GRO_CB(p)->same_flow = 0;
+	}
+
+	skb_gro_pull(skb, MTK_HDR_LEN);
+	skb_gro_postpull_rcsum(skb, data, MTK_HDR_LEN);
+
+	pp = call_gro_receive(ptype->callbacks.gro_receive, head, skb);
+
+out_unlock:
+	rcu_read_unlock();
+out:
+	skb_gro_flush_final(skb, pp, flush);
+
+	return pp;
+}
+
+static int mtk_tag_gro_complete(struct sk_buff *skb, int nhoff)
+{
+	const struct packet_offload *ptype;
+	int err = -ENOENT;
+	__be16 proto;
+
+	proto = mtk_tag_encap_proto(skb->data + nhoff);
+
+	rcu_read_lock();
+
+	ptype = gro_find_complete_by_type(proto);
+	if (ptype)
+		err = ptype->callbacks.gro_complete(skb, nhoff + MTK_HDR_LEN);
+
+	rcu_read_unlock();
+
+	return err;
+}
+
 static const struct dsa_device_ops mtk_netdev_ops = {
 	.name		= "mtk",
 	.proto		= DSA_TAG_PROTO_MTK,
 	.xmit		= mtk_tag_xmit,
 	.rcv		= mtk_tag_rcv,
 	.flow_dissect	= mtk_tag_flow_dissect,
+	.gro_receive	= mtk_tag_gro_receive,
+	.gro_complete	= mtk_tag_gro_complete,
 	.overhead	= MTK_HDR_LEN,
 };
 
-- 
2.24.1