The jumbo frame uses the 'RTE_ETHER_MAX_LEN' as boundary condition,
but the Ether overhead is larger than 18 when it supports dual VLAN tags.
That will cause the jumbo flag rx offload is wrong when MTU size is
'RTE_ETHER_MTU'.

This fix will change the boundary condition with 'RTE_ETHER_MTU' and
overhead, that perhaps impacts the cases of the jumbo frame related.

Fixes: 0e2efd02db58 ("net/octeontx2: add MTU set operation")

Acked-by: Nithin Dabilpuram <redacted>

Signed-off-by: Steve Yang <redacted>
---
 drivers/net/octeontx2/otx2_ethdev.h     | 2 ++
 drivers/net/octeontx2/otx2_ethdev_ops.c | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/octeontx2/otx2_ethdev.h b/drivers/net/octeontx2/otx2_ethdev.h
index 3b9871f4dc..99f0469d89 100644
--- a/drivers/net/octeontx2/otx2_ethdev.h
+++ b/drivers/net/octeontx2/otx2_ethdev.h

@@ -51,6 +51,8 @@
 /* ETH_HLEN+ETH_FCS+2*VLAN_HLEN */
 #define NIX_L2_OVERHEAD \
 	(RTE_ETHER_HDR_LEN + RTE_ETHER_CRC_LEN + 8)
+#define NIX_L2_MAX_LEN \
+	(RTE_ETHER_MTU + NIX_L2_OVERHEAD)
 
 /* HW config of frame size doesn't include FCS */
 #define NIX_MAX_HW_FRS			9212

diff --git a/drivers/net/octeontx2/otx2_ethdev_ops.c b/drivers/net/octeontx2/otx2_ethdev_ops.c
index b36d37b9f7..963cc285ed 100644
--- a/drivers/net/octeontx2/otx2_ethdev_ops.c
+++ b/drivers/net/octeontx2/otx2_ethdev_ops.c

@@ -58,7 +58,7 @@ otx2_nix_mtu_set(struct rte_eth_dev *eth_dev, uint16_t mtu)
 	if (rc)
 		return rc;
 
-	if (frame_size > RTE_ETHER_MAX_LEN)
+	if (frame_size > NIX_L2_MAX_LEN)
 		dev->rx_offloads |= DEV_RX_OFFLOAD_JUMBO_FRAME;
 	else
 		dev->rx_offloads &= ~DEV_RX_OFFLOAD_JUMBO_FRAME;

-- 
2.17.1