netfilter: flowtable: add function to invoke garbage collection immediately

Expose nf_flow_table_gc_run() to force a garbage collector run from the
offload infrastructure.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/net/netfilter/nf_flow_table.h

@@ -270,6 +270,7 @@ void flow_offload_refresh(struct nf_flowtable *flow_table,
 
 struct flow_offload_tuple_rhash *flow_offload_lookup(struct nf_flowtable *flow_table,
 						     struct flow_offload_tuple *tuple);
+void nf_flow_table_gc_run(struct nf_flowtable *flow_table);
 void nf_flow_table_gc_cleanup(struct nf_flowtable *flowtable,
 			      struct net_device *dev);
 void nf_flow_table_cleanup(struct net_device *dev);

net/netfilter/nf_flow_table_core.c

@@ -437,12 +437,17 @@ static void nf_flow_offload_gc_step(struct nf_flowtable *flow_table,
 	}
 }
 
+void nf_flow_table_gc_run(struct nf_flowtable *flow_table)
+{
+	nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, NULL);
+}
+
 static void nf_flow_offload_work_gc(struct work_struct *work)
 {
 	struct nf_flowtable *flow_table;
 
 	flow_table = container_of(work, struct nf_flowtable, gc_work.work);
-	nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, NULL);
+	nf_flow_table_gc_run(flow_table);
 	queue_delayed_work(system_power_efficient_wq, &flow_table->gc_work, HZ);
 }
 
@@ -601,10 +606,11 @@ void nf_flow_table_free(struct nf_flowtable *flow_table)
 
 	cancel_delayed_work_sync(&flow_table->gc_work);
 	nf_flow_table_iterate(flow_table, nf_flow_table_do_cleanup, NULL);
-	nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, NULL);
+	nf_flow_table_gc_run(flow_table);
 	nf_flow_table_offload_flush(flow_table);
 	if (nf_flowtable_hw_offload(flow_table))
-		nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, NULL);
+		nf_flow_table_gc_run(flow_table);
+
 	rhashtable_destroy(&flow_table->rhashtable);
 }
 EXPORT_SYMBOL_GPL(nf_flow_table_free);