ibmveth: Fix max MTU limit

[ Upstream commit 5948378b26d89f8aa5eac37629dbd0616ce8d7a7 ]

The max MTU limit defined for ibmveth is not accounting for
virtual ethernet buffer overhead, which is twenty-two additional
bytes set aside for the ethernet header and eight additional bytes
of an opaque handle reserved for use by the hypervisor. Update the
max MTU to reflect this overhead.

Fixes: d894be57ca92 ("ethernet: use net core MTU range checking in more drivers")
Fixes: 110447f8269a ("ethernet: fix min/max MTU typos")
Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/ibm/ibmveth.c b/drivers/net/ethernet/ibm/ibmveth.c
index c5be4ebd84373ec9ff8ade34b4bae3031e937652..aa32a5b04112907f3f6d809ba9ba26a55cfdef38 100644 (file)
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c
@@ -1682,7 +1682,7 @@ static int ibmveth_probe(struct vio_dev *dev, const struct vio_device_id *id)
        }
 
        netdev->min_mtu = IBMVETH_MIN_MTU;
-       netdev->max_mtu = ETH_MAX_MTU;
+       netdev->max_mtu = ETH_MAX_MTU - IBMVETH_BUFF_OH;
 
        memcpy(netdev->dev_addr, mac_addr_p, ETH_ALEN);