openvswitch: Print error when ovs_execute_actions() fails

Currently in function ovs_dp_process_packet(), return values of
ovs_execute_actions() are silently discarded. This patch prints out
an debug message when error happens so as to provide helpful hints
for debugging.
Acked-by: Pravin B Shelar <[e-mail]>

Signed-off-by: David S. Miller <[e-mail]>

net/openvswitch/datapath.c

···
 	struct dp_stats_percpu *stats;
 	u64 *stats_counter;
 	u32 n_mask_hit;
+	int error;
 
 	stats = this_cpu_ptr(dp->stats_percpu);
 
···
 	flow = ovs_flow_tbl_lookup_stats(&dp->table, key, &n_mask_hit);
 	if (unlikely(!flow)) {
 		struct dp_upcall_info upcall;
-		int error;
 
 		memset(&upcall, 0, sizeof(upcall));
 		upcall.cmd = OVS_PACKET_CMD_MISS;
···
 
 	ovs_flow_stats_update(flow, key->tp.flags, skb);
 	sf_acts = rcu_dereference(flow->sf_acts);
-	ovs_execute_actions(dp, skb, sf_acts, key);
+	error = ovs_execute_actions(dp, skb, sf_acts, key);
+	if (unlikely(error))
+		net_dbg_ratelimited("ovs: action execution error on datapath %s: %d\n",
+							ovs_dp_name(dp), error);
 
 	stats_counter = &stats->n_hit;