Subject: [PATCH net 2/3] i40e: add double of VLAN header when computing the max MTU

From: Jason Xing <[email-masked]>
Date: Sat, 4 Feb 2023 21:35:34 +0800

From: Jason Xing <[email-masked]>

Include the second VLAN HLEN into account when computing the maximum
MTU size as other drivers do.

Fixes: 0c8493d90b6b ("i40e: add XDP support for pass and drop actions")
Signed-off-by: Jason Xing <[email-masked]>
---
 drivers/net/ethernet/intel/i40e/i40e.h      | 2 ++
 drivers/net/ethernet/intel/i40e/i40e_main.c | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e.h b/drivers/net/ethernet/intel/i40e/i40e.h
index 60e351665c70..e03853d3c706 100644
--- a/drivers/net/ethernet/intel/i40e/i40e.h
+++ b/drivers/net/ethernet/intel/i40e/i40e.h
@@ -107,6 +107,8 @@
 #define I40E_BW_MBPS_DIVISOR		125000 /* rate / (1000000 / 8) Mbps */
 #define I40E_MAX_BW_INACTIVE_ACCUM	4 /* accumulate 4 credits max */
 
+#define I40E_PACKET_HDR_PAD (ETH_HLEN + ETH_FCS_LEN + (VLAN_HLEN * 2))
+
 /* driver state flags */
 enum i40e_state_t {
 	__I40E_TESTING,
diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index 53d0083e35da..d039928f3646 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -2921,7 +2921,7 @@ static int i40e_change_mtu(struct net_device *netdev, int new_mtu)
 	struct i40e_pf *pf = vsi->back;
 
 	if (i40e_enabled_xdp_vsi(vsi)) {
-		int frame_size = new_mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN;
+		int frame_size = new_mtu + I40E_PACKET_HDR_PAD;
 
 		if (frame_size > i40e_max_xdp_frame_size(vsi))
 			return -EINVAL;
-- 
2.37.3