ixgb: don't allow too small MTU

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/net/ixgb/ixgb_main.c b/drivers/net/ixgb/ixgb_main.c
index 60cad65dbc2e..0e72dadf8b70 100644
--- a/drivers/net/ixgb/ixgb_main.c
+++ b/drivers/net/ixgb/ixgb_main.c
@@ -1566,9 +1566,9 @@ ixgb_change_mtu(struct net_device *netdev, int new_mtu)
         int max_frame = new_mtu + ENET_HEADER_SIZE + ENET_FCS_LENGTH;
         int old_max_frame = netdev->mtu + ENET_HEADER_SIZE + ENET_FCS_LENGTH;
 
-
-        if((max_frame < IXGB_MIN_ENET_FRAME_SIZE_WITHOUT_FCS + ENET_FCS_LENGTH)
-           || (max_frame > IXGB_MAX_JUMBO_FRAME_SIZE + ENET_FCS_LENGTH)) {
+        /* MTU < 68 is an error for IPv4 traffic, just don't allow it */
+        if ((new_mtu < 68) ||
+            (max_frame > IXGB_MAX_JUMBO_FRAME_SIZE + ENET_FCS_LENGTH)) {
                 DPRINTK(PROBE, ERR, "Invalid MTU setting %d\n", new_mtu);
                 return -EINVAL;
         }