[PATCH 1/2] 8139too: Allow setting MTU larger than 1500

From: Alban Bedel
Date: Sat Nov 08 2014 - 06:49:10 EST


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

Signed-off-by: Alban Bedel <albeu@xxxxxxx>
---
drivers/net/ethernet/realtek/8139too.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/realtek/8139too.c b/drivers/net/ethernet/realtek/8139too.c
index 007b38c..8387de9 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,
--
2.0.0

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