net: hns3: refactor function hns3_fill_skb_desc to simplify code

The function hns3_fill_skb_desc is hard to read, this patch
extract 2 functions and add new a struct data to simplify the
code and Improve readability.
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -1544,16 +1544,29 @@ static bool hns3_check_hw_tx_csum(struct sk_buff *skb)
 	return true;
 }
 
-static int hns3_fill_skb_desc(struct hns3_enet_ring *ring,
-			      struct sk_buff *skb, struct hns3_desc *desc,
-			      struct hns3_desc_cb *desc_cb)
+struct hns3_desc_param {
+	u32 paylen_ol4cs;
+	u32 ol_type_vlan_len_msec;
+	u32 type_cs_vlan_tso;
+	u16 mss_hw_csum;
+	u16 inner_vtag;
+	u16 out_vtag;
+};
+
+static void hns3_init_desc_data(struct sk_buff *skb, struct hns3_desc_param *pa)
+{
+	pa->paylen_ol4cs = skb->len;
+	pa->ol_type_vlan_len_msec = 0;
+	pa->type_cs_vlan_tso = 0;
+	pa->mss_hw_csum = 0;
+	pa->inner_vtag = 0;
+	pa->out_vtag = 0;
+}
+
+static int hns3_handle_vlan_info(struct hns3_enet_ring *ring,
+				 struct sk_buff *skb,
+				 struct hns3_desc_param *param)
 {
-	u32 ol_type_vlan_len_msec = 0;
-	u32 paylen_ol4cs = skb->len;
-	u32 type_cs_vlan_tso = 0;
-	u16 mss_hw_csum = 0;
-	u16 inner_vtag = 0;
-	u16 out_vtag = 0;
 	int ret;
 
 	ret = hns3_handle_vtags(ring, skb);
@@ -1561,67 +1574,93 @@ static int hns3_fill_skb_desc(struct hns3_enet_ring *ring,
 		hns3_ring_stats_update(ring, tx_vlan_err);
 		return ret;
 	} else if (ret == HNS3_INNER_VLAN_TAG) {
-		inner_vtag = skb_vlan_tag_get(skb);
-		inner_vtag |= (skb->priority << VLAN_PRIO_SHIFT) &
+		param->inner_vtag = skb_vlan_tag_get(skb);
+		param->inner_vtag |= (skb->priority << VLAN_PRIO_SHIFT) &
 				VLAN_PRIO_MASK;
-		hns3_set_field(type_cs_vlan_tso, HNS3_TXD_VLAN_B, 1);
+		hns3_set_field(param->type_cs_vlan_tso, HNS3_TXD_VLAN_B, 1);
 	} else if (ret == HNS3_OUTER_VLAN_TAG) {
-		out_vtag = skb_vlan_tag_get(skb);
-		out_vtag |= (skb->priority << VLAN_PRIO_SHIFT) &
+		param->out_vtag = skb_vlan_tag_get(skb);
+		param->out_vtag |= (skb->priority << VLAN_PRIO_SHIFT) &
 				VLAN_PRIO_MASK;
-		hns3_set_field(ol_type_vlan_len_msec, HNS3_TXD_OVLAN_B,
+		hns3_set_field(param->ol_type_vlan_len_msec, HNS3_TXD_OVLAN_B,
 			       1);
 	}
+	return 0;
+}
 
-	desc_cb->send_bytes = skb->len;
+static int hns3_handle_csum_partial(struct hns3_enet_ring *ring,
+				    struct sk_buff *skb,
+				    struct hns3_desc_cb *desc_cb,
+				    struct hns3_desc_param *param)
+{
+	u8 ol4_proto, il4_proto;
+	int ret;
 
-	if (skb->ip_summed == CHECKSUM_PARTIAL) {
-		u8 ol4_proto, il4_proto;
-
-		if (hns3_check_hw_tx_csum(skb)) {
-			/* set checksum start and offset, defined in 2 Bytes */
-			hns3_set_field(type_cs_vlan_tso, HNS3_TXD_CSUM_START_S,
-				       skb_checksum_start_offset(skb) >> 1);
-			hns3_set_field(ol_type_vlan_len_msec,
-				       HNS3_TXD_CSUM_OFFSET_S,
-				       skb->csum_offset >> 1);
-			mss_hw_csum |= BIT(HNS3_TXD_HW_CS_B);
-			goto out_hw_tx_csum;
-		}
+	if (hns3_check_hw_tx_csum(skb)) {
+		/* set checksum start and offset, defined in 2 Bytes */
+		hns3_set_field(param->type_cs_vlan_tso, HNS3_TXD_CSUM_START_S,
+			       skb_checksum_start_offset(skb) >> 1);
+		hns3_set_field(param->ol_type_vlan_len_msec,
+			       HNS3_TXD_CSUM_OFFSET_S,
+			       skb->csum_offset >> 1);
+		param->mss_hw_csum |= BIT(HNS3_TXD_HW_CS_B);
+		return 0;
+	}
 
-		skb_reset_mac_len(skb);
+	skb_reset_mac_len(skb);
 
-		ret = hns3_get_l4_protocol(skb, &ol4_proto, &il4_proto);
-		if (unlikely(ret < 0)) {
-			hns3_ring_stats_update(ring, tx_l4_proto_err);
-			return ret;
-		}
+	ret = hns3_get_l4_protocol(skb, &ol4_proto, &il4_proto);
+	if (unlikely(ret < 0)) {
+		hns3_ring_stats_update(ring, tx_l4_proto_err);
+		return ret;
+	}
 
-		ret = hns3_set_l2l3l4(skb, ol4_proto, il4_proto,
-				      &type_cs_vlan_tso,
-				      &ol_type_vlan_len_msec);
-		if (unlikely(ret < 0)) {
-			hns3_ring_stats_update(ring, tx_l2l3l4_err);
-			return ret;
-		}
+	ret = hns3_set_l2l3l4(skb, ol4_proto, il4_proto,
+			      &param->type_cs_vlan_tso,
+			      &param->ol_type_vlan_len_msec);
+	if (unlikely(ret < 0)) {
+		hns3_ring_stats_update(ring, tx_l2l3l4_err);
+		return ret;
+	}
+
+	ret = hns3_set_tso(skb, &param->paylen_ol4cs, &param->mss_hw_csum,
+			   &param->type_cs_vlan_tso, &desc_cb->send_bytes);
+	if (unlikely(ret < 0)) {
+		hns3_ring_stats_update(ring, tx_tso_err);
+		return ret;
+	}
+	return 0;
+}
 
-		ret = hns3_set_tso(skb, &paylen_ol4cs, &mss_hw_csum,
-				   &type_cs_vlan_tso, &desc_cb->send_bytes);
-		if (unlikely(ret < 0)) {
-			hns3_ring_stats_update(ring, tx_tso_err);
+static int hns3_fill_skb_desc(struct hns3_enet_ring *ring,
+			      struct sk_buff *skb, struct hns3_desc *desc,
+			      struct hns3_desc_cb *desc_cb)
+{
+	struct hns3_desc_param param;
+	u8 fd_op;
+	int ret;
+
+	hns3_init_desc_data(skb, &param);
+	ret = hns3_handle_vlan_info(ring, skb, &param);
+	if (unlikely(ret < 0))
+		return ret;
+
+	desc_cb->send_bytes = skb->len;
+
+	if (skb->ip_summed == CHECKSUM_PARTIAL) {
+		ret = hns3_handle_csum_partial(ring, skb, desc_cb, &param);
+		if (ret)
 			return ret;
-		}
 	}
 
-out_hw_tx_csum:
 	/* Set txbd */
 	desc->tx.ol_type_vlan_len_msec =
-		cpu_to_le32(ol_type_vlan_len_msec);
-	desc->tx.type_cs_vlan_tso_len = cpu_to_le32(type_cs_vlan_tso);
-	desc->tx.paylen_ol4cs = cpu_to_le32(paylen_ol4cs);
-	desc->tx.mss_hw_csum = cpu_to_le16(mss_hw_csum);
-	desc->tx.vlan_tag = cpu_to_le16(inner_vtag);
-	desc->tx.outer_vlan_tag = cpu_to_le16(out_vtag);
+		cpu_to_le32(param.ol_type_vlan_len_msec);
+	desc->tx.type_cs_vlan_tso_len = cpu_to_le32(param.type_cs_vlan_tso);
+	desc->tx.paylen_ol4cs = cpu_to_le32(param.paylen_ol4cs);
+	desc->tx.mss_hw_csum = cpu_to_le16(param.mss_hw_csum);
+	desc->tx.vlan_tag = cpu_to_le16(param.inner_vtag);
+	desc->tx.outer_vlan_tag = cpu_to_le16(param.out_vtag);
 
 	return 0;
 }