net/mlx4_en: Do not count LLC/SNAP in MTU calculation

LLC/SNAP 8 bytes should not be added as part of header calculation.
If used, payload will be decreased accordingly. For MTU of 1500
we'll set 1522 instead of 1523.
Signed-off-by: NYishai Hadas <yishaih@mellanox.com>
Reviewed-by: NLiran Liss <liranl@mellanox.com>
Signed-off-by: NEugenia Emantayev <eugenia@mellanox.com>
Signed-off-by: NAmir Vadai <amirv@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/en_rx.c

@@ -922,7 +922,7 @@ static const int frag_sizes[] = {
 void mlx4_en_calc_rx_buf(struct net_device *dev)
 {
 	struct mlx4_en_priv *priv = netdev_priv(dev);
-	int eff_mtu = dev->mtu + ETH_HLEN + VLAN_HLEN + ETH_LLC_SNAP_SIZE;
+	int eff_mtu = dev->mtu + ETH_HLEN + VLAN_HLEN;
 	int buf_size = 0;
 	int i = 0;
 

drivers/net/ethernet/mellanox/mlx4/mlx4_en.h

@@ -152,8 +152,6 @@ enum {
 #define MLX4_EN_TX_POLL_MODER	16
 #define MLX4_EN_TX_POLL_TIMEOUT	(HZ / 4)
 
-#define ETH_LLC_SNAP_SIZE	8
-
 #define SMALL_PACKET_SIZE      (256 - NET_IP_ALIGN)
 #define HEADER_COPY_SIZE       (128 - NET_IP_ALIGN)
 #define MLX4_LOOPBACK_TEST_PAYLOAD (HEADER_COPY_SIZE - ETH_HLEN)