[dpdk-dev] [PATCH v2] net/i40e: consider QinQ when setting MTU

[Wenzhuo Lu]

When counting max packet length from MTU, count
VLAN tag length twice for QinQ packets.

Signed-off-by: Wenzhuo Lu <wenzhuo.lu at intel.com>
Acked-by: Jingjing Wu <jingjing.wu at intel.com>
---
 drivers/net/i40e/i40e_ethdev.c    | 3 +--
 drivers/net/i40e/i40e_ethdev.h    | 7 +++++++
 drivers/net/i40e/i40e_ethdev_vf.c | 3 +--
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/net/i40e/i40e_ethdev.c b/drivers/net/i40e/i40e_ethdev.c
index 3fa25dc..e713c11 100644
--- a/drivers/net/i40e/i40e_ethdev.c
+++ b/drivers/net/i40e/i40e_ethdev.c
@@ -10592,8 +10592,7 @@ static void i40e_set_default_mac_addr(struct rte_eth_dev *dev,
 {
 	struct i40e_pf *pf = I40E_DEV_PRIVATE_TO_PF(dev->data->dev_private);
 	struct rte_eth_dev_data *dev_data = pf->dev_data;
-	uint32_t frame_size = mtu + ETHER_HDR_LEN
-			      + ETHER_CRC_LEN + I40E_VLAN_TAG_SIZE;
+	uint32_t frame_size = mtu + I40E_ETH_OVERHEAD;
 	int ret = 0;
 
 	/* check if mtu is within the allowed range */
diff --git a/drivers/net/i40e/i40e_ethdev.h b/drivers/net/i40e/i40e_ethdev.h
index 71b0874..2ff8282 100644
--- a/drivers/net/i40e/i40e_ethdev.h
+++ b/drivers/net/i40e/i40e_ethdev.h
@@ -251,6 +251,13 @@ enum i40e_flxpld_layer_idx {
 	I40E_INSET_FLEX_PAYLOAD_W5 | I40E_INSET_FLEX_PAYLOAD_W6 | \
 	I40E_INSET_FLEX_PAYLOAD_W7 | I40E_INSET_FLEX_PAYLOAD_W8)
 
+/**
+ * The overhead from MTU to max frame size.
+ * Considering QinQ packet, the VLAN tag needs to be counted twice.
+ */
+#define I40E_ETH_OVERHEAD \
+	(ETHER_HDR_LEN + ETHER_CRC_LEN + I40E_VLAN_TAG_SIZE * 2)
+
 struct i40e_adapter;
 
 /**
diff --git a/drivers/net/i40e/i40e_ethdev_vf.c b/drivers/net/i40e/i40e_ethdev_vf.c
index cb34023..d27f09d 100644
--- a/drivers/net/i40e/i40e_ethdev_vf.c
+++ b/drivers/net/i40e/i40e_ethdev_vf.c
@@ -2687,8 +2687,7 @@ static int eth_i40evf_pci_remove(struct rte_pci_device *pci_dev)
 {
 	struct i40e_vf *vf = I40EVF_DEV_PRIVATE_TO_VF(dev->data->dev_private);
 	struct rte_eth_dev_data *dev_data = vf->dev_data;
-	uint32_t frame_size = mtu + ETHER_HDR_LEN
-			      + ETHER_CRC_LEN + I40E_VLAN_TAG_SIZE;
+	uint32_t frame_size = mtu + I40E_ETH_OVERHEAD;
 	int ret = 0;
 
 	/* check if mtu is within the allowed range */
-- 
1.9.3