ethtool: Ethtool parameter to dynamically change tx_copybreak

Use new ethtool [sg]et_tunable() to set tx_copybread (inline threshold)
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NAmir Vadai <amirv@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/uapi/linux/ethtool.h

@@ -212,6 +212,7 @@ struct ethtool_value {
 enum tunable_id {
 	ETHTOOL_ID_UNSPEC,
 	ETHTOOL_RX_COPYBREAK,
+	ETHTOOL_TX_COPYBREAK,
 };
 
 enum tunable_type_id {

net/core/ethtool.c

@@ -1625,6 +1625,7 @@ static int ethtool_tunable_valid(const struct ethtool_tunable *tuna)
 {
 	switch (tuna->id) {
 	case ETHTOOL_RX_COPYBREAK:
+	case ETHTOOL_TX_COPYBREAK:
 		if (tuna->len != sizeof(u32) ||
 		    tuna->type_id != ETHTOOL_TUNABLE_U32)
 			return -EINVAL;