[PATCH 4.14 004/105] net: ethernet: octeon_mgmt: Account for second possible VLAN header

[Greg Kroah-Hartman]

From: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx>

[ Upstream commit e4dd5608033efe7b6030cde359bfdbaeb73bc22d ]

Octeon's input ring-buffer entry has 14 bits-wide size field, so to account
for second possible VLAN header max_mtu must be further reduced.

Fixes: 109cc16526c6d ("ethernet/cavium: use core min/max MTU checking")
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/cavium/octeon/octeon_mgmt.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/ethernet/cavium/octeon/octeon_mgmt.c
+++ b/drivers/net/ethernet/cavium/octeon/octeon_mgmt.c
@@ -1497,7 +1497,7 @@ static int octeon_mgmt_probe(struct plat
 	netdev->ethtool_ops = &octeon_mgmt_ethtool_ops;
 
 	netdev->min_mtu = 64 - OCTEON_MGMT_RX_HEADROOM;
-	netdev->max_mtu = 16383 - OCTEON_MGMT_RX_HEADROOM;
+	netdev->max_mtu = 16383 - OCTEON_MGMT_RX_HEADROOM - VLAN_HLEN;
 
 	mac = of_get_mac_address(pdev->dev.of_node);