net/octeontx2: fix jumbo frame flag condition for MTU

[ upstream commit 3a921cd ]

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: 0e2efd0 ("net/octeontx2: add MTU set operation")

Signed-off-by: Steve Yang <stevex.yang@intel.com>
Acked-by: Nithin Dabilpuram <ndabilpuram@marvell.com>

drivers/net/octeontx2/otx2_ethdev.h

@@ -50,6 +50,8 @@
 /* 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

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;