8139too: Allow setting MTU larger than 1500

Replace the default ndo_change_mtu callback with one that allow
setting MTU that the driver can handle.

Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 1 deletions

diff --git a/drivers/net/ethernet/realtek/8139too.c b/drivers/net/ethernet/realtek/8139too.c
index 007b38cce69a..8387de985c06 100644
--- a/drivers/net/ethernet/realtek/8139too.c
+++ b/drivers/net/ethernet/realtek/8139too.c
@@ -185,6 +185,9 @@ static int debug = -1;
 /* max supported ethernet frame size -- must be at least (dev->mtu+14+4).*/
 #define MAX_ETH_FRAME_SIZE      1536
 
+/* max supported payload size */
+#define MAX_ETH_DATA_SIZE       (MAX_ETH_FRAME_SIZE - ETH_HLEN - ETH_FCS_LEN)
+
 /* Size of the Tx bounce buffers -- must be at least (dev->mtu+14+4). */
 #define TX_BUF_SIZE     MAX_ETH_FRAME_SIZE
 #define TX_BUF_TOT_LEN  (TX_BUF_SIZE * NUM_TX_DESC)
@@ -920,11 +923,19 @@ static int rtl8139_set_features(struct net_device *dev, netdev_features_t featur
         return 0;
 }
 
+static int rtl8139_change_mtu(struct net_device *dev, int new_mtu)
+{
+        if (new_mtu < 68 || new_mtu > MAX_ETH_DATA_SIZE)
+                return -EINVAL;
+        dev->mtu = new_mtu;
+        return 0;
+}
+
 static const struct net_device_ops rtl8139_netdev_ops = {
         .ndo_open               = rtl8139_open,
         .ndo_stop               = rtl8139_close,
         .ndo_get_stats64        = rtl8139_get_stats64,
-        .ndo_change_mtu         = eth_change_mtu,
+        .ndo_change_mtu         = rtl8139_change_mtu,
         .ndo_validate_addr      = eth_validate_addr,
         .ndo_set_mac_address    = rtl8139_set_mac_address,
         .ndo_start_xmit         = rtl8139_start_xmit,