be2net: bug fix in be_change_mtu

Current code allows the new mtu to cross the supported value.
This patch fixes the boundary checks.

From: Suresh R <sureshr@serverengines.com>
Signed-off-by: Ajit Khaparde <ajitk@serverengines.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/net/benet/be_main.c b/drivers/net/benet/be_main.c
index 99061488eeb3..c65c63427d41 100644
--- a/drivers/net/benet/be_main.c
+++ b/drivers/net/benet/be_main.c
@@ -473,10 +473,12 @@ static int be_change_mtu(struct net_device *netdev, int new_mtu)
 {
         struct be_adapter *adapter = netdev_priv(netdev);
         if (new_mtu < BE_MIN_MTU ||
-                        new_mtu > BE_MAX_JUMBO_FRAME_SIZE) {
+                        new_mtu > (BE_MAX_JUMBO_FRAME_SIZE -
+                                        (ETH_HLEN + ETH_FCS_LEN))) {
                 dev_info(&adapter->pdev->dev,
                         "MTU must be between %d and %d bytes\n",
-                        BE_MIN_MTU, BE_MAX_JUMBO_FRAME_SIZE);
+                        BE_MIN_MTU,
+                        (BE_MAX_JUMBO_FRAME_SIZE - (ETH_HLEN + ETH_FCS_LEN)));
                 return -EINVAL;
         }
         dev_info(&adapter->pdev->dev, "MTU changed from %d to %d bytes\n",