net: hns3: fix for fraglist SKB headlen not handling correctly

When the fraglist SKB headlen is larger than zero, current code
still handle the fraglist SKB linear data as frag data, which may
cause TX error.

This patch adds a new DESC_TYPE_FRAGLIST_SKB type to handle the
mapping and unmapping of the fraglist SKB linear data buffer.

Fixes: 8ae10cfb ("net: hns3: support tx-scatter-gather-fraglist feature")
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/hisilicon/hns3/hnae3.h

@@ -78,6 +78,7 @@
 
 enum hns_desc_type {
 	DESC_TYPE_SKB,
+	DESC_TYPE_FRAGLIST_SKB,
 	DESC_TYPE_PAGE,
 };
 

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

@@ -1106,6 +1106,10 @@ static int hns3_fill_desc(struct hns3_enet_ring *ring, void *priv,
 		if (unlikely(ret < 0))
 			return ret;
 
+		dma = dma_map_single(dev, skb->data, size, DMA_TO_DEVICE);
+	} else if (type == DESC_TYPE_FRAGLIST_SKB) {
+		struct sk_buff *skb = (struct sk_buff *)priv;
+
 		dma = dma_map_single(dev, skb->data, size, DMA_TO_DEVICE);
 	} else {
 		frag = (skb_frag_t *)priv;
@@ -1144,8 +1148,9 @@ static int hns3_fill_desc(struct hns3_enet_ring *ring, void *priv,
 		/* The txbd's baseinfo of DESC_TYPE_PAGE & DESC_TYPE_SKB */
 		desc_cb->priv = priv;
 		desc_cb->dma = dma + HNS3_MAX_BD_SIZE * k;
-		desc_cb->type = (type == DESC_TYPE_SKB && !k) ?
-				DESC_TYPE_SKB : DESC_TYPE_PAGE;
+		desc_cb->type = ((type == DESC_TYPE_FRAGLIST_SKB ||
+				  type == DESC_TYPE_SKB) && !k) ?
+				type : DESC_TYPE_PAGE;
 
 		/* now, fill the descriptor */
 		desc->addr = cpu_to_le64(dma + HNS3_MAX_BD_SIZE * k);
@@ -1354,7 +1359,9 @@ static void hns3_clear_desc(struct hns3_enet_ring *ring, int next_to_use_orig)
 		ring_ptr_move_bw(ring, next_to_use);
 
 		/* unmap the descriptor dma address */
-		if (ring->desc_cb[ring->next_to_use].type == DESC_TYPE_SKB)
+		if (ring->desc_cb[ring->next_to_use].type == DESC_TYPE_SKB ||
+		    ring->desc_cb[ring->next_to_use].type ==
+		    DESC_TYPE_FRAGLIST_SKB)
 			dma_unmap_single(dev,
 					 ring->desc_cb[ring->next_to_use].dma,
 					ring->desc_cb[ring->next_to_use].length,
@@ -1447,7 +1454,8 @@ netdev_tx_t hns3_nic_net_xmit(struct sk_buff *skb, struct net_device *netdev)
 		goto out;
 
 	skb_walk_frags(skb, frag_skb) {
-		ret = hns3_fill_skb_to_desc(ring, frag_skb, DESC_TYPE_PAGE);
+		ret = hns3_fill_skb_to_desc(ring, frag_skb,
+					    DESC_TYPE_FRAGLIST_SKB);
 		if (unlikely(ret < 0))
 			goto fill_err;
 
@@ -2356,7 +2364,7 @@ static int hns3_map_buffer(struct hns3_enet_ring *ring, struct hns3_desc_cb *cb)
 static void hns3_unmap_buffer(struct hns3_enet_ring *ring,
 			      struct hns3_desc_cb *cb)
 {
-	if (cb->type == DESC_TYPE_SKB)
+	if (cb->type == DESC_TYPE_SKB || cb->type == DESC_TYPE_FRAGLIST_SKB)
 		dma_unmap_single(ring_to_dev(ring), cb->dma, cb->length,
 				 ring_to_dma_dir(ring));
 	else if (cb->length)