net: hns: fix for unmapping problem when SMMU is on

If SMMU is on, there is more likely that skb_shinfo(skb)->frags[i]
can not send by a single BD. when this happen, the
hns_nic_net_xmit_hw function map the whole data in a frags using
skb_frag_dma_map, but unmap each BD' data individually when tx is
done, which causes problem when SMMU is on.

This patch fixes this problem by ummapping the whole data in a
frags when tx is done.
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Reviewed-by: Yisen Zhuang <yisen.zhuang@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/hisilicon/hns/hnae.c

@@ -84,7 +84,7 @@ static void hnae_unmap_buffer(struct hnae_ring *ring, struct hnae_desc_cb *cb)
 	if (cb->type == DESC_TYPE_SKB)
 		dma_unmap_single(ring_to_dev(ring), cb->dma, cb->length,
 				 ring_to_dma_dir(ring));
-	else
+	else if (cb->length)
 		dma_unmap_page(ring_to_dev(ring), cb->dma, cb->length,
 			       ring_to_dma_dir(ring));
 }

drivers/net/ethernet/hisilicon/hns/hns_enet.c

@@ -40,8 +40,8 @@
 #define SKB_TMP_LEN(SKB) \
 	(((SKB)->transport_header - (SKB)->mac_header) + tcp_hdrlen(SKB))
 
-static void fill_v2_desc(struct hnae_ring *ring, void *priv,
-			 int size, dma_addr_t dma, int frag_end,
+static void fill_v2_desc_hw(struct hnae_ring *ring, void *priv, int size,
+			    int send_sz, dma_addr_t dma, int frag_end,
 			    int buf_num, enum hns_desc_type type, int mtu)
 {
 	struct hnae_desc *desc = &ring->desc[ring->next_to_use];
@@ -64,7 +64,7 @@ static void fill_v2_desc(struct hnae_ring *ring, void *priv,
 	desc_cb->type = type;
 
 	desc->addr = cpu_to_le64(dma);
-	desc->tx.send_size = cpu_to_le16((u16)size);
+	desc->tx.send_size = cpu_to_le16((u16)send_sz);
 
 	/* config bd buffer end */
 	hnae_set_bit(rrcfv, HNSV2_TXD_VLD_B, 1);
@@ -133,6 +133,14 @@ static void fill_v2_desc(struct hnae_ring *ring, void *priv,
 	ring_ptr_move_fw(ring, next_to_use);
 }
 
+static void fill_v2_desc(struct hnae_ring *ring, void *priv,
+			 int size, dma_addr_t dma, int frag_end,
+			 int buf_num, enum hns_desc_type type, int mtu)
+{
+	fill_v2_desc_hw(ring, priv, size, size, dma, frag_end,
+			buf_num, type, mtu);
+}
+
 static const struct acpi_device_id hns_enet_acpi_match[] = {
 	{ "HISI00C1", 0 },
 	{ "HISI00C2", 0 },
@@ -289,7 +297,7 @@ static void fill_tso_desc(struct hnae_ring *ring, void *priv,
 
 	/* when the frag size is bigger than hardware, split this frag */
 	for (k = 0; k < frag_buf_num; k++)
-		fill_v2_desc(ring, priv,
+		fill_v2_desc_hw(ring, priv, k == 0 ? size : 0,
 				(k == frag_buf_num - 1) ?
 					sizeoflast : BD_MAX_SEND_SIZE,
 				dma + BD_MAX_SEND_SIZE * k,