netdevice: add queue selection fallback handler for ndo_select_queue

Add a new argument for ndo_select_queue() callback that passes a
fallback handler. This gets invoked through netdev_pick_tx();
fallback handler is currently __netdev_pick_tx() as most drivers
invoke this function within their customized implementation in
case for skbs that don't need any special handling. This fallback
handler can then be replaced on other call-sites with different
queue selection methods (e.g. in packet sockets, pktgen etc).

This also has the nice side-effect that __netdev_pick_tx() is
then only invoked from netdev_pick_tx() and export of that
function to modules can be undone.

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

drivers/net/bonding/bond_main.c

···
 
 
 static u16 bond_select_queue(struct net_device *dev, struct sk_buff *skb,
-			     void *accel_priv)
+			     void *accel_priv, select_queue_fallback_t fallback)
 {
 	/*
 	 * This helper function exists to help dev_pick_tx get the correct

drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c

···
 }
 
 u16 bnx2x_select_queue(struct net_device *dev, struct sk_buff *skb,
-		       void *accel_priv)
+		       void *accel_priv, select_queue_fallback_t fallback)
 {
 	struct bnx2x *bp = netdev_priv(dev);
 
···
 	}
 
 	/* select a non-FCoE queue */
-	return __netdev_pick_tx(dev, skb) % BNX2X_NUM_ETH_QUEUES(bp);
+	return fallback(dev, skb) % BNX2X_NUM_ETH_QUEUES(bp);
 }
 
 void bnx2x_set_num_queues(struct bnx2x *bp)

drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.h

···
 
 /* select_queue callback */
 u16 bnx2x_select_queue(struct net_device *dev, struct sk_buff *skb,
-		       void *accel_priv);
+		       void *accel_priv, select_queue_fallback_t fallback);
 
 static inline void bnx2x_update_rx_prod(struct bnx2x *bp,
 					struct bnx2x_fastpath *fp,

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

···
 }
 
 static u16 ixgbe_select_queue(struct net_device *dev, struct sk_buff *skb,
-			      void *accel_priv)
+			      void *accel_priv, select_queue_fallback_t fallback)
 {
 	struct ixgbe_fwd_adapter *fwd_adapter = accel_priv;
 #ifdef IXGBE_FCOE
···
 		if (adapter->flags & IXGBE_FLAG_FCOE_ENABLED)
 			break;
 	default:
-		return __netdev_pick_tx(dev, skb);
+		return fallback(dev, skb);
 	}
 
 	f = &adapter->ring_feature[RING_F_FCOE];
···
 
 	return txq + f->offset;
 #else
-	return __netdev_pick_tx(dev, skb);
+	return fallback(dev, skb);
 #endif
 }
 

drivers/net/ethernet/lantiq_etop.c

···
 
 static u16
 ltq_etop_select_queue(struct net_device *dev, struct sk_buff *skb,
-		      void *accel_priv)
+		      void *accel_priv, select_queue_fallback_t fallback)
 {
 	/* we are currently only using the first queue */
 	return 0;

drivers/net/ethernet/mellanox/mlx4/en_tx.c

···
 }
 
 u16 mlx4_en_select_queue(struct net_device *dev, struct sk_buff *skb,
-			 void *accel_priv)
+			 void *accel_priv, select_queue_fallback_t fallback)
 {
 	struct mlx4_en_priv *priv = netdev_priv(dev);
 	u16 rings_p_up = priv->num_tx_rings_p_up;
···
 	if (vlan_tx_tag_present(skb))
 		up = vlan_tx_tag_get(skb) >> VLAN_PRIO_SHIFT;
 
-	return __netdev_pick_tx(dev, skb) % rings_p_up + up * rings_p_up;
+	return fallback(dev, skb) % rings_p_up + up * rings_p_up;
 }
 
 static void mlx4_bf_copy(void __iomem *dst, unsigned long *src, unsigned bytecnt)

drivers/net/ethernet/mellanox/mlx4/mlx4_en.h

···
 
 void mlx4_en_tx_irq(struct mlx4_cq *mcq);
 u16 mlx4_en_select_queue(struct net_device *dev, struct sk_buff *skb,
-			 void *accel_priv);
+			 void *accel_priv, select_queue_fallback_t fallback);
 netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev);
 
 int mlx4_en_create_tx_ring(struct mlx4_en_priv *priv,

drivers/net/ethernet/tile/tilegx.c

···
 
 /* Return subqueue id on this core (one per core). */
 static u16 tile_net_select_queue(struct net_device *dev, struct sk_buff *skb,
-				 void *accel_priv)
+				 void *accel_priv, select_queue_fallback_t fallback)
 {
 	return smp_processor_id();
 }

drivers/net/team/team.c

···
 }
 
 static u16 team_select_queue(struct net_device *dev, struct sk_buff *skb,
-			     void *accel_priv)
+			     void *accel_priv, select_queue_fallback_t fallback)
 {
 	/*
 	 * This helper function exists to help dev_pick_tx get the correct

drivers/net/tun.c

···
  * hope the rxq no. may help here.
  */
 static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
-			    void *accel_priv)
+			    void *accel_priv, select_queue_fallback_t fallback)
 {
 	struct tun_struct *tun = netdev_priv(dev);
 	struct tun_flow_entry *e;

drivers/net/wireless/mwifiex/main.c

···
 
 static u16
 mwifiex_netdev_select_wmm_queue(struct net_device *dev, struct sk_buff *skb,
-				void *accel_priv)
+				void *accel_priv, select_queue_fallback_t fallback)
 {
 	skb->priority = cfg80211_classify8021d(skb, NULL);
 	return mwifiex_1d_to_wmm_queue[skb->priority];

drivers/staging/bcm/Bcmnet.c

···
 }
 
 static u16 bcm_select_queue(struct net_device *dev, struct sk_buff *skb,
-			    void *accel_priv)
+			    void *accel_priv, select_queue_fallback_t fallback)
 {
 	return ClassifyPacket(netdev_priv(dev), skb);
 }

drivers/staging/netlogic/xlr_net.c

···
 }
 
 static u16 xlr_net_select_queue(struct net_device *ndev, struct sk_buff *skb,
-				void *accel_priv)
+				void *accel_priv, select_queue_fallback_t fallback)
 {
 	return (u16)smp_processor_id();
 }

drivers/staging/rtl8188eu/os_dep/os_intfs.c

···
 }
 
 static u16 rtw_select_queue(struct net_device *dev, struct sk_buff *skb,
-			    void *accel_priv)
+			    void *accel_priv, select_queue_fallback_t fallback)
 {
 	struct adapter	*padapter = rtw_netdev_priv(dev);
 	struct mlme_priv *pmlmepriv = &padapter->mlmepriv;

include/linux/netdevice.h

···
 	unsigned char id_len;
 };
 
+typedef u16 (*select_queue_fallback_t)(struct net_device *dev,
+				       struct sk_buff *skb);
+
 /*
  * This structure defines the management hooks for network devices.
  * The following hooks can be defined; unless noted otherwise, they are
···
  *	Required can not be NULL.
  *
  * u16 (*ndo_select_queue)(struct net_device *dev, struct sk_buff *skb,
- *                         void *accel_priv);
+ *                         void *accel_priv, select_queue_fallback_t fallback);
  *	Called to decide which queue to when device supports multiple
  *	transmit queues.
  *
···
 						   struct net_device *dev);
 	u16			(*ndo_select_queue)(struct net_device *dev,
 						    struct sk_buff *skb,
-						    void *accel_priv);
+						    void *accel_priv,
+						    select_queue_fallback_t fallback);
 	void			(*ndo_change_rx_flags)(struct net_device *dev,
 						       int flags);
 	void			(*ndo_set_rx_mode)(struct net_device *dev);
···
 struct netdev_queue *netdev_pick_tx(struct net_device *dev,
 				    struct sk_buff *skb,
 				    void *accel_priv);
-u16 __netdev_pick_tx(struct net_device *dev, struct sk_buff *skb);
 
 /*
  * Net namespace inlines

net/core/flow_dissector.c

···
 #endif
 }
 
-u16 __netdev_pick_tx(struct net_device *dev, struct sk_buff *skb)
+static u16 __netdev_pick_tx(struct net_device *dev, struct sk_buff *skb)
 {
 	struct sock *sk = skb->sk;
 	int queue_index = sk_tx_queue_get(sk);
···
 
 	return queue_index;
 }
-EXPORT_SYMBOL(__netdev_pick_tx);
 
 struct netdev_queue *netdev_pick_tx(struct net_device *dev,
 				    struct sk_buff *skb,
···
 	if (dev->real_num_tx_queues != 1) {
 		const struct net_device_ops *ops = dev->netdev_ops;
 		if (ops->ndo_select_queue)
-			queue_index = ops->ndo_select_queue(dev, skb,
-							    accel_priv);
+			queue_index = ops->ndo_select_queue(dev, skb, accel_priv,
+							    __netdev_pick_tx);
 		else
 			queue_index = __netdev_pick_tx(dev, skb);
 

net/mac80211/iface.c

···
 
 static u16 ieee80211_netdev_select_queue(struct net_device *dev,
 					 struct sk_buff *skb,
-					 void *accel_priv)
+					 void *accel_priv,
+					 select_queue_fallback_t fallback)
 {
 	return ieee80211_select_queue(IEEE80211_DEV_TO_SUB_IF(dev), skb);
 }
···
 
 static u16 ieee80211_monitor_select_queue(struct net_device *dev,
 					  struct sk_buff *skb,
-					  void *accel_priv)
+					  void *accel_priv,
+					  select_queue_fallback_t fallback)
 {
 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 	struct ieee80211_local *local = sdata->local;