dev: packet: make packet_direct_xmit a common function

The new dev_direct_xmit will be used by AF_XDP in later commits.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

include/linux/netdevice.h

@@ -2486,6 +2486,7 @@ void dev_disable_lro(struct net_device *dev);
 int dev_loopback_xmit(struct net *net, struct sock *sk, struct sk_buff *newskb);
 int dev_queue_xmit(struct sk_buff *skb);
 int dev_queue_xmit_accel(struct sk_buff *skb, void *accel_priv);
+int dev_direct_xmit(struct sk_buff *skb, u16 queue_id);
 int register_netdevice(struct net_device *dev);
 void unregister_netdevice_queue(struct net_device *dev, struct list_head *head);
 void unregister_netdevice_many(struct list_head *head);

net/core/dev.c

@@ -3625,6 +3625,44 @@ int dev_queue_xmit_accel(struct sk_buff *skb, void *accel_priv)
 }
 EXPORT_SYMBOL(dev_queue_xmit_accel);
 
+int dev_direct_xmit(struct sk_buff *skb, u16 queue_id)
+{
+	struct net_device *dev = skb->dev;
+	struct sk_buff *orig_skb = skb;
+	struct netdev_queue *txq;
+	int ret = NETDEV_TX_BUSY;
+	bool again = false;
+
+	if (unlikely(!netif_running(dev) ||
+		     !netif_carrier_ok(dev)))
+		goto drop;
+
+	skb = validate_xmit_skb_list(skb, dev, &again);
+	if (skb != orig_skb)
+		goto drop;
+
+	skb_set_queue_mapping(skb, queue_id);
+	txq = skb_get_tx_queue(dev, skb);
+
+	local_bh_disable();
+
+	HARD_TX_LOCK(dev, txq, smp_processor_id());
+	if (!netif_xmit_frozen_or_drv_stopped(txq))
+		ret = netdev_start_xmit(skb, dev, txq, false);
+	HARD_TX_UNLOCK(dev, txq);
+
+	local_bh_enable();
+
+	if (!dev_xmit_complete(ret))
+		kfree_skb(skb);
+
+	return ret;
+drop:
+	atomic_long_inc(&dev->tx_dropped);
+	kfree_skb_list(skb);
+	return NET_XMIT_DROP;
+}
+EXPORT_SYMBOL(dev_direct_xmit);
 
 /*************************************************************************
  *			Receiver routines

net/packet/af_packet.c

@@ -209,7 +209,7 @@ static void prb_clear_rxhash(struct tpacket_kbdq_core *,
 static void prb_fill_vlan_info(struct tpacket_kbdq_core *,
 		struct tpacket3_hdr *);
 static void packet_flush_mclist(struct sock *sk);
-static void packet_pick_tx_queue(struct net_device *dev, struct sk_buff *skb);
+static u16 packet_pick_tx_queue(struct sk_buff *skb);
 
 struct packet_skb_cb {
 	union {
@@ -243,40 +243,7 @@ static void __fanout_link(struct sock *sk, struct packet_sock *po);
 
 static int packet_direct_xmit(struct sk_buff *skb)
 {
-	struct net_device *dev = skb->dev;
-	struct sk_buff *orig_skb = skb;
-	struct netdev_queue *txq;
-	int ret = NETDEV_TX_BUSY;
-	bool again = false;
-
-	if (unlikely(!netif_running(dev) ||
-		     !netif_carrier_ok(dev)))
-		goto drop;
-
-	skb = validate_xmit_skb_list(skb, dev, &again);
-	if (skb != orig_skb)
-		goto drop;
-
-	packet_pick_tx_queue(dev, skb);
-	txq = skb_get_tx_queue(dev, skb);
-
-	local_bh_disable();
-
-	HARD_TX_LOCK(dev, txq, smp_processor_id());
-	if (!netif_xmit_frozen_or_drv_stopped(txq))
-		ret = netdev_start_xmit(skb, dev, txq, false);
-	HARD_TX_UNLOCK(dev, txq);
-
-	local_bh_enable();
-
-	if (!dev_xmit_complete(ret))
-		kfree_skb(skb);
-
-	return ret;
-drop:
-	atomic_long_inc(&dev->tx_dropped);
-	kfree_skb_list(skb);
-	return NET_XMIT_DROP;
+	return dev_direct_xmit(skb, packet_pick_tx_queue(skb));
 }
 
 static struct net_device *packet_cached_dev_get(struct packet_sock *po)
@@ -313,8 +280,9 @@ static u16 __packet_pick_tx_queue(struct net_device *dev, struct sk_buff *skb)
 	return (u16) raw_smp_processor_id() % dev->real_num_tx_queues;
 }
 
-static void packet_pick_tx_queue(struct net_device *dev, struct sk_buff *skb)
+static u16 packet_pick_tx_queue(struct sk_buff *skb)
 {
+	struct net_device *dev = skb->dev;
 	const struct net_device_ops *ops = dev->netdev_ops;
 	u16 queue_index;
 
@@ -326,7 +294,7 @@ static void packet_pick_tx_queue(struct net_device *dev, struct sk_buff *skb)
 		queue_index = __packet_pick_tx_queue(dev, skb);
 	}
 
-	skb_set_queue_mapping(skb, queue_index);
+	return queue_index;
 }
 
 /* __register_prot_hook must be invoked through register_prot_hook