mlxsw: switchx2: Fix memory leak at skb reallocation

[ Upstream commit 400fc010 ]

During transmission the skb is checked for headroom in order to
add vendor specific header. In case the skb needs to be re-allocated,
skb_realloc_headroom() is called to make a private copy of the original,
but doesn't release it. Current code assumes that the original skb is
released during reallocation and only releases it at the error path
which causes a memory leak.

Fix this by adding the original skb release to the main path.

Fixes: d003462a ("mlxsw: Simplify mlxsw_sx_port_xmit function")
Signed-off-by: Arkadi Sharshevsky <arkadis@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/ethernet/mellanox/mlxsw/switchx2.c

@@ -313,6 +313,7 @@ static netdev_tx_t mlxsw_sx_port_xmit(struct sk_buff *skb,
 			dev_kfree_skb_any(skb_orig);
 			return NETDEV_TX_OK;
 		}
+		dev_consume_skb_any(skb_orig);
 	}
 	mlxsw_sx_txhdr_construct(skb, &tx_info);
 	len = skb->len;