net: Move napi polling code out of net_rx_action

This patch creates a new function napi_poll and moves the napi
polling code from net_rx_action into it.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -4557,32 +4557,11 @@ void netif_napi_del(struct napi_struct *napi)
 }
 EXPORT_SYMBOL(netif_napi_del);
 
-static void net_rx_action(struct softirq_action *h)
+static int napi_poll(struct napi_struct *n, struct list_head *repoll)
 {
-	struct softnet_data *sd = this_cpu_ptr(&softnet_data);
-	unsigned long time_limit = jiffies + 2;
-	int budget = netdev_budget;
-	LIST_HEAD(list);
-	LIST_HEAD(repoll);
 	void *have;
-
-	local_irq_disable();
-	list_splice_init(&sd->poll_list, &list);
-	local_irq_enable();
-
-	while (!list_empty(&list)) {
-		struct napi_struct *n;
 	int work, weight;
 
-		/* If softirq window is exhausted then punt.
-		 * Allow this to run for 2 jiffies since which will allow
-		 * an average latency of 1.5/HZ.
-		 */
-		if (unlikely(budget <= 0 || time_after_eq(jiffies, time_limit)))
-			goto softnet_break;
-
-
-		n = list_first_entry(&list, struct napi_struct, poll_list);
 	list_del_init(&n->poll_list);
 
 	have = netpoll_poll_lock(n);
@@ -4603,28 +4582,59 @@ static void net_rx_action(struct softirq_action *h)
 
 	WARN_ON_ONCE(work > weight);
 
-		budget -= work;
+	if (likely(work < weight))
+		goto out_unlock;
 
 	/* Drivers must not modify the NAPI state if they
 	 * consume the entire weight.  In such cases this code
 	 * still "owns" the NAPI instance and therefore can
 	 * move the instance around on the list at-will.
 	 */
-		if (unlikely(work == weight)) {
 	if (unlikely(napi_disable_pending(n))) {
 		napi_complete(n);
-			} else {
+		goto out_unlock;
+	}
+
 	if (n->gro_list) {
 		/* flush too old packets
 		 * If HZ < 1000, flush all packets.
 		 */
 		napi_gro_flush(n, HZ >= 1000);
 	}
-				list_add_tail(&n->poll_list, &repoll);
-			}
-		}
 
+	list_add_tail(&n->poll_list, repoll);
+
+out_unlock:
 	netpoll_poll_unlock(have);
+
+	return work;
+}
+
+static void net_rx_action(struct softirq_action *h)
+{
+	struct softnet_data *sd = this_cpu_ptr(&softnet_data);
+	unsigned long time_limit = jiffies + 2;
+	int budget = netdev_budget;
+	LIST_HEAD(list);
+	LIST_HEAD(repoll);
+
+	local_irq_disable();
+	list_splice_init(&sd->poll_list, &list);
+	local_irq_enable();
+
+	while (!list_empty(&list)) {
+		struct napi_struct *n;
+
+		/* If softirq window is exhausted then punt.
+		 * Allow this to run for 2 jiffies since which will allow
+		 * an average latency of 1.5/HZ.
+		 */
+		if (unlikely(budget <= 0 || time_after_eq(jiffies, time_limit)))
+			goto softnet_break;
+
+
+		n = list_first_entry(&list, struct napi_struct, poll_list);
+		budget -= napi_poll(n, &repoll);
 	}
 
 	if (!sd_has_rps_ipi_waiting(sd) &&