netfilter: flowtable: add nf_flow_offload_work_alloc()

Add helper function to allocate and initialize flow offload work and use
it to consolidate existing code.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nf_flow_table_offload.c

@@ -748,21 +748,35 @@ static void flow_offload_queue_work(struct flow_offload_work *offload)
 	schedule_work(&nf_flow_offload_work);
 }
 
-void nf_flow_offload_add(struct nf_flowtable *flowtable,
-			 struct flow_offload *flow)
+static struct flow_offload_work *
+nf_flow_offload_work_alloc(struct nf_flowtable *flowtable,
+			   struct flow_offload *flow, unsigned int cmd)
 {
 	struct flow_offload_work *offload;
 
 	offload = kmalloc(sizeof(struct flow_offload_work), GFP_ATOMIC);
 	if (!offload)
-		return;
+		return NULL;
 
-	offload->cmd = FLOW_CLS_REPLACE;
+	offload->cmd = cmd;
 	offload->flow = flow;
 	offload->priority = flowtable->priority;
 	offload->flowtable = flowtable;
-	flow->flags |= FLOW_OFFLOAD_HW;
 
+	return offload;
+}
+
+
+void nf_flow_offload_add(struct nf_flowtable *flowtable,
+			 struct flow_offload *flow)
+{
+	struct flow_offload_work *offload;
+
+	offload = nf_flow_offload_work_alloc(flowtable, flow, FLOW_CLS_REPLACE);
+	if (!offload)
+		return;
+
+	flow->flags |= FLOW_OFFLOAD_HW;
 	flow_offload_queue_work(offload);
 }
 
@@ -771,15 +785,11 @@ void nf_flow_offload_del(struct nf_flowtable *flowtable,
 {
 	struct flow_offload_work *offload;
 
-	offload = kzalloc(sizeof(struct flow_offload_work), GFP_ATOMIC);
+	offload = nf_flow_offload_work_alloc(flowtable, flow, FLOW_CLS_DESTROY);
 	if (!offload)
 		return;
 
-	offload->cmd = FLOW_CLS_DESTROY;
-	offload->flow = flow;
-	offload->flow->flags |= FLOW_OFFLOAD_HW_DYING;
-	offload->flowtable = flowtable;
-
+	flow->flags |= FLOW_OFFLOAD_HW_DYING;
 	flow_offload_queue_work(offload);
 }
 
@@ -793,14 +803,10 @@ void nf_flow_offload_stats(struct nf_flowtable *flowtable,
 	if ((delta >= (9 * NF_FLOW_TIMEOUT) / 10))
 		return;
 
-	offload = kzalloc(sizeof(struct flow_offload_work), GFP_ATOMIC);
+	offload = nf_flow_offload_work_alloc(flowtable, flow, FLOW_CLS_STATS);
 	if (!offload)
 		return;
 
-	offload->cmd = FLOW_CLS_STATS;
-	offload->flow = flow;
-	offload->flowtable = flowtable;
-
 	flow_offload_queue_work(offload);
 }