flow_offload: reject to offload tc actions in offload drivers

A follow-up patch will allow users to offload tc actions independent of
classifier in the software datapath.

In preparation for this, teach all drivers that support offload of the flow
tables to reject such configuration as currently none of them support it.

Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt_tc.c

@@ -1962,7 +1962,7 @@ static int bnxt_tc_setup_indr_cb(struct net_device *netdev, struct Qdisc *sch, v
 				 void *data,
 				 void (*cleanup)(struct flow_block_cb *block_cb))
 {
-	if (!bnxt_is_netdev_indr_offload(netdev))
+	if (!netdev || !bnxt_is_netdev_indr_offload(netdev))
 		return -EOPNOTSUPP;
 
 	switch (type) {

drivers/net/ethernet/mellanox/mlx5/core/en/rep/tc.c

@@ -517,6 +517,9 @@ int mlx5e_rep_indr_setup_cb(struct net_device *netdev, struct Qdisc *sch, void *
 			    void *data,
 			    void (*cleanup)(struct flow_block_cb *block_cb))
 {
+	if (!netdev)
+		return -EOPNOTSUPP;
+
 	switch (type) {
 	case TC_SETUP_BLOCK:
 		return mlx5e_rep_indr_setup_block(netdev, sch, cb_priv, type_data,

drivers/net/ethernet/netronome/nfp/flower/offload.c

@@ -1867,6 +1867,9 @@ nfp_flower_indr_setup_tc_cb(struct net_device *netdev, struct Qdisc *sch, void *
 			    void *data,
 			    void (*cleanup)(struct flow_block_cb *block_cb))
 {
+	if (!netdev)
+		return -EOPNOTSUPP;
+
 	if (!nfp_fl_is_netdev_to_offload(netdev))
 		return -EOPNOTSUPP;