[PATCH 4.19 272/293] net: hns3: pad the short tunnel frame before sending to hardware

[Greg Kroah-Hartman]

From: Yufeng Mo <moyufeng@xxxxxxxxxx>

commit d18e81183b1cb9c309266cbbce9acd3e0c528d04 upstream.

The hardware cannot handle short tunnel frames below 65 bytes,
and will cause vlan tag missing problem. So pads packet size to
65 bytes for tunnel frames to fix this bug.

Fixes: 3db084d28dc0("net: hns3: Fix for vxlan tx checksum bug")
Signed-off-by: Yufeng Mo <moyufeng@xxxxxxxxxx>
Signed-off-by: Guangbin Huang <huangguangbin2@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/hisilicon/hns3/hns3_enet.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -29,6 +29,8 @@ static const char hns3_driver_string[] =
 static const char hns3_copyright[] = "Copyright (c) 2017 Huawei Corporation.";
 static struct hnae3_client client;
 
+#define HNS3_MIN_TUN_PKT_LEN	65U
+
 /* hns3_pci_tbl - PCI Device ID Table
  *
  * Last entry must be all 0s
@@ -792,8 +794,11 @@ static int hns3_set_l3l4_type_csum(struc
 				HNS3_L4T_TCP);
 		break;
 	case IPPROTO_UDP:
-		if (hns3_tunnel_csum_bug(skb))
-			return skb_checksum_help(skb);
+		if (hns3_tunnel_csum_bug(skb)) {
+			int ret = skb_put_padto(skb, HNS3_MIN_TUN_PKT_LEN);
+
+			return ret ? ret : skb_checksum_help(skb);
+		}
 
 		hnae3_set_bit(*type_cs_vlan_tso, HNS3_TXD_L4CS_B, 1);
 		hnae3_set_field(*type_cs_vlan_tso,