net: hns3: Fixes the static check warning due to missing unsupp L3 proto check

This patch fixes the static check warning due to missing handling leg of
unsupported L3 protocol type in the hns3_get_l4_protocol() function.

Fixes: 76ad4f0e ("net: hns3: Add support of HNS3 Ethernet Driver for
hip08 SoC")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/hisilicon/hns3/hns3pf/hns3_enet.c

@@ -436,8 +436,8 @@ static int hns3_set_tso(struct sk_buff *skb, u32 *paylen,
 	return 0;
 }
 
-static void hns3_get_l4_protocol(struct sk_buff *skb, u8 *ol4_proto,
-				 u8 *il4_proto)
+static int hns3_get_l4_protocol(struct sk_buff *skb, u8 *ol4_proto,
+				u8 *il4_proto)
 {
 	union {
 		struct iphdr *v4;
@@ -461,6 +461,8 @@ static void hns3_get_l4_protocol(struct sk_buff *skb, u8 *ol4_proto,
 					 &l4_proto_tmp, &frag_off);
 	} else if (skb->protocol == htons(ETH_P_IP)) {
 		l4_proto_tmp = l3.v4->protocol;
+	} else {
+		return -EINVAL;
 	}
 
 	*ol4_proto = l4_proto_tmp;
@@ -468,7 +470,7 @@ static void hns3_get_l4_protocol(struct sk_buff *skb, u8 *ol4_proto,
 	/* tunnel packet */
 	if (!skb->encapsulation) {
 		*il4_proto = 0;
-		return;
+		return 0;
 	}
 
 	/* find inner header point */
@@ -486,6 +488,8 @@ static void hns3_get_l4_protocol(struct sk_buff *skb, u8 *ol4_proto,
 	}
 
 	*il4_proto = l4_proto_tmp;
+
+	return 0;
 }
 
 static void hns3_set_l2l3l4_len(struct sk_buff *skb, u8 ol4_proto,
@@ -757,7 +761,9 @@ static int hns3_fill_desc(struct hns3_enet_ring *ring, void *priv,
 				protocol = vlan_get_protocol(skb);
 				skb->protocol = protocol;
 			}
-			hns3_get_l4_protocol(skb, &ol4_proto, &il4_proto);
+			ret = hns3_get_l4_protocol(skb, &ol4_proto, &il4_proto);
+			if (ret)
+				return ret;
 			hns3_set_l2l3l4_len(skb, ol4_proto, il4_proto,
 					    &type_cs_vlan_tso,
 					    &ol_type_vlan_len_msec);