net: add netif_tx_napi_add()

netif_tx_napi_add() is a variant of netif_napi_add()

It should be used by drivers that use a napi structure
to exclusively poll TX.

We do not want to add this kind of napi in napi_hash[] in following
patches, adding generic busy polling to all NAPI drivers.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bcmsysport.c

@@ -1216,7 +1216,7 @@ static int bcm_sysport_init_tx_ring(struct bcm_sysport_priv *priv,
 	/* Initialize SW view of the ring */
 	spin_lock_init(&ring->lock);
 	ring->priv = priv;
-	netif_napi_add(priv->netdev, &ring->napi, bcm_sysport_tx_poll, 64);
+	netif_tx_napi_add(priv->netdev, &ring->napi, bcm_sysport_tx_poll, 64);
 	ring->index = index;
 	ring->size = size;
 	ring->alloc_size = ring->size;

drivers/net/ethernet/broadcom/genet/bcmgenet.c

@@ -2041,11 +2041,11 @@ static void bcmgenet_init_tx_napi(struct bcmgenet_priv *priv)
 
 	for (i = 0; i < priv->hw_params->tx_queues; ++i) {
 		ring = &priv->tx_rings[i];
-		netif_napi_add(priv->dev, &ring->napi, bcmgenet_tx_poll, 64);
+		netif_tx_napi_add(priv->dev, &ring->napi, bcmgenet_tx_poll, 64);
 	}
 
 	ring = &priv->tx_rings[DESC_INDEX];
-	netif_napi_add(priv->dev, &ring->napi, bcmgenet_tx_poll, 64);
+	netif_tx_napi_add(priv->dev, &ring->napi, bcmgenet_tx_poll, 64);
 }
 
 static void bcmgenet_enable_tx_napi(struct bcmgenet_priv *priv)

drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c

@@ -1050,7 +1050,7 @@ static int fs_enet_probe(struct platform_device *ofdev)
 	ndev->netdev_ops = &fs_enet_netdev_ops;
 	ndev->watchdog_timeo = 2 * HZ;
 	netif_napi_add(ndev, &fep->napi, fs_enet_rx_napi, fpi->napi_weight);
-	netif_napi_add(ndev, &fep->napi_tx, fs_enet_tx_napi, 2);
+	netif_tx_napi_add(ndev, &fep->napi_tx, fs_enet_tx_napi, 2);
 
 	ndev->ethtool_ops = &fs_ethtool_ops;
 

drivers/net/ethernet/freescale/gianfar.c

@@ -1347,12 +1347,12 @@ static int gfar_probe(struct platform_device *ofdev)
 		if (priv->poll_mode == GFAR_SQ_POLLING) {
 			netif_napi_add(dev, &priv->gfargrp[i].napi_rx,
 				       gfar_poll_rx_sq, GFAR_DEV_WEIGHT);
-			netif_napi_add(dev, &priv->gfargrp[i].napi_tx,
+			netif_tx_napi_add(dev, &priv->gfargrp[i].napi_tx,
 				       gfar_poll_tx_sq, 2);
 		} else {
 			netif_napi_add(dev, &priv->gfargrp[i].napi_rx,
 				       gfar_poll_rx, GFAR_DEV_WEIGHT);
-			netif_napi_add(dev, &priv->gfargrp[i].napi_tx,
+			netif_tx_napi_add(dev, &priv->gfargrp[i].napi_tx,
 				       gfar_poll_tx, 2);
 		}
 	}

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

@@ -156,7 +156,7 @@ int mlx4_en_activate_cq(struct mlx4_en_priv *priv, struct mlx4_en_cq *cq,
 	cq->mcq.event = mlx4_en_cq_event;
 
 	if (cq->is_tx) {
-		netif_napi_add(cq->dev, &cq->napi, mlx4_en_poll_tx_cq,
+		netif_tx_napi_add(cq->dev, &cq->napi, mlx4_en_poll_tx_cq,
 				  NAPI_POLL_WEIGHT);
 	} else {
 		netif_napi_add(cq->dev, &cq->napi, mlx4_en_poll_rx_cq, 64);

drivers/net/ethernet/qlogic/qlcnic/qlcnic_io.c

@@ -1604,7 +1604,7 @@ int qlcnic_82xx_napi_add(struct qlcnic_adapter *adapter,
 	if (qlcnic_check_multi_tx(adapter) && !adapter->ahw->diag_test) {
 		for (ring = 0; ring < adapter->drv_tx_rings; ring++) {
 			tx_ring = &adapter->tx_ring[ring];
-			netif_napi_add(netdev, &tx_ring->napi, qlcnic_tx_poll,
+			netif_tx_napi_add(netdev, &tx_ring->napi, qlcnic_tx_poll,
 				       NAPI_POLL_WEIGHT);
 		}
 	}
@@ -2135,7 +2135,7 @@ int qlcnic_83xx_napi_add(struct qlcnic_adapter *adapter,
 	    !(adapter->flags & QLCNIC_TX_INTR_SHARED)) {
 		for (ring = 0; ring < adapter->drv_tx_rings; ring++) {
 			tx_ring = &adapter->tx_ring[ring];
-			netif_napi_add(netdev, &tx_ring->napi,
+			netif_tx_napi_add(netdev, &tx_ring->napi,
 				       qlcnic_83xx_msix_tx_poll,
 				       NAPI_POLL_WEIGHT);
 		}

drivers/net/ethernet/rocker/rocker.c

@@ -4998,7 +4998,7 @@ static int rocker_probe_port(struct rocker *rocker, unsigned int port_number)
 	dev->netdev_ops = &rocker_port_netdev_ops;
 	dev->ethtool_ops = &rocker_port_ethtool_ops;
 	dev->switchdev_ops = &rocker_port_switchdev_ops;
-	netif_napi_add(dev, &rocker_port->napi_tx, rocker_port_poll_tx,
+	netif_tx_napi_add(dev, &rocker_port->napi_tx, rocker_port_poll_tx,
 		       NAPI_POLL_WEIGHT);
 	netif_napi_add(dev, &rocker_port->napi_rx, rocker_port_poll_rx,
 		       NAPI_POLL_WEIGHT);

drivers/net/ethernet/ti/cpsw.c

@@ -2469,7 +2469,7 @@ static int cpsw_probe(struct platform_device *pdev)
 	ndev->netdev_ops = &cpsw_netdev_ops;
 	ndev->ethtool_ops = &cpsw_ethtool_ops;
 	netif_napi_add(ndev, &priv->napi_rx, cpsw_rx_poll, CPSW_POLL_WEIGHT);
-	netif_napi_add(ndev, &priv->napi_tx, cpsw_tx_poll, CPSW_POLL_WEIGHT);
+	netif_tx_napi_add(ndev, &priv->napi_tx, cpsw_tx_poll, CPSW_POLL_WEIGHT);
 
 	/* register the network device */
 	SET_NETDEV_DEV(ndev, &pdev->dev);

drivers/net/ethernet/ti/netcp_core.c

@@ -1990,7 +1990,7 @@ static int netcp_create_interface(struct netcp_device *netcp_device,
 
 	/* NAPI register */
 	netif_napi_add(ndev, &netcp->rx_napi, netcp_rx_poll, NETCP_NAPI_WEIGHT);
-	netif_napi_add(ndev, &netcp->tx_napi, netcp_tx_poll, NETCP_NAPI_WEIGHT);
+	netif_tx_napi_add(ndev, &netcp->tx_napi, netcp_tx_poll, NETCP_NAPI_WEIGHT);
 
 	/* Register the network device */
 	ndev->dev_id		= 0;

drivers/net/wireless/ath/wil6210/netdev.c

@@ -183,7 +183,7 @@ void *wil_if_alloc(struct device *dev)
 
 	netif_napi_add(ndev, &wil->napi_rx, wil6210_netdev_poll_rx,
 		       WIL6210_NAPI_BUDGET);
-	netif_napi_add(ndev, &wil->napi_tx, wil6210_netdev_poll_tx,
+	netif_tx_napi_add(ndev, &wil->napi_tx, wil6210_netdev_poll_tx,
 		       WIL6210_NAPI_BUDGET);
 
 	netif_tx_stop_all_queues(ndev);

include/linux/netdevice.h

@@ -326,7 +326,8 @@ enum {
 	NAPI_STATE_SCHED,	/* Poll is scheduled */
 	NAPI_STATE_DISABLE,	/* Disable pending */
 	NAPI_STATE_NPSVC,	/* Netpoll - don't dequeue from poll_list */
-	NAPI_STATE_HASHED,	/* In NAPI hash */
+	NAPI_STATE_HASHED,	/* In NAPI hash (busy polling possible) */
+	NAPI_STATE_NO_BUSY_POLL,/* Do not add in napi_hash, no busy polling */
 };
 
 enum gro_result {
@@ -1938,6 +1939,26 @@ static inline void *netdev_priv(const struct net_device *dev)
 void netif_napi_add(struct net_device *dev, struct napi_struct *napi,
 		    int (*poll)(struct napi_struct *, int), int weight);
 
+/**
+ *	netif_tx_napi_add - initialize a napi context
+ *	@dev:  network device
+ *	@napi: napi context
+ *	@poll: polling function
+ *	@weight: default weight
+ *
+ * This variant of netif_napi_add() should be used from drivers using NAPI
+ * to exclusively poll a TX queue.
+ * This will avoid we add it into napi_hash[], thus polluting this hash table.
+ */
+static inline void netif_tx_napi_add(struct net_device *dev,
+				     struct napi_struct *napi,
+				     int (*poll)(struct napi_struct *, int),
+				     int weight)
+{
+	set_bit(NAPI_STATE_NO_BUSY_POLL, &napi->state);
+	netif_napi_add(dev, napi, poll, weight);
+}
+
 /**
  *  netif_napi_del - remove a napi context
  *  @napi: napi context

net/core/dev.c

@@ -4737,7 +4737,8 @@ EXPORT_SYMBOL(sk_busy_loop);
 
 void napi_hash_add(struct napi_struct *napi)
 {
-	if (test_and_set_bit(NAPI_STATE_HASHED, &napi->state))
+	if (test_bit(NAPI_STATE_NO_BUSY_POLL, &napi->state) ||
+	    test_and_set_bit(NAPI_STATE_HASHED, &napi->state))
 		return;
 
 	spin_lock(&napi_hash_lock);