[NET]: Make NAPI polling independent of struct net_device objects.

Several devices have multiple independant RX queues per net
device, and some have a single interrupt doorbell for several
queues.

In either case, it's easier to support layouts like that if the
structure representing the poll is independant from the net
device itself.

The signature of the ->poll() call back goes from:

	int foo_poll(struct net_device *dev, int *budget)

to

	int foo_poll(struct napi_struct *napi, int budget)

The caller is returned the number of RX packets processed (or
the number of "NAPI credits" consumed if you want to get
abstract).  The callee no longer messes around bumping
dev->quota, *budget, etc. because that is all handled in the
caller upon return.

The napi_struct is to be embedded in the device driver private data
structures.

Furthermore, it is the driver's responsibility to disable all NAPI
instances in it's ->stop() device close handler.  Since the
napi_struct is privatized into the driver's private data structures,
only the driver knows how to get at all of the napi_struct instances
it may have per-device.

With lots of help and suggestions from Rusty Russell, Roland Dreier,
Michael Chan, Jeff Garzik, and Jamal Hadi Salim.

Bug fixes from Thomas Graf, Roland Dreier, Peter Zijlstra,
Joseph Fannin, Scott Wood, Hans J. Koch, and Michael Chan.

[ Ported to current tree and all drivers converted.  Integrated
  Stephen's follow-on kerneldoc additions, and restored poll_list
  handling to the old style to fix mutual exclusion issues.  -DaveM ]

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 47 insertions, 35 deletions

diff --git a/drivers/net/pcnet32.c b/drivers/net/pcnet32.c
index e6a67531de9..a9973490dba 100644
--- a/drivers/net/pcnet32.c
+++ b/drivers/net/pcnet32.c
@@ -280,6 +280,8 @@ struct pcnet32_private {
 	unsigned int		dirty_rx,	/* ring entries to be freed. */
 				dirty_tx;
 
+	struct net_device	*dev;
+	struct napi_struct	napi;
 	struct net_device_stats	stats;
 	char			tx_full;
 	char			phycount;	/* number of phys found */
@@ -440,15 +442,21 @@ static struct pcnet32_access pcnet32_dwio = {
 
 static void pcnet32_netif_stop(struct net_device *dev)
 {
+	struct pcnet32_private *lp = netdev_priv(dev);
 	dev->trans_start = jiffies;
-	netif_poll_disable(dev);
+#ifdef CONFIG_PCNET32_NAPI
+	napi_disable(&lp->napi);
+#endif
 	netif_tx_disable(dev);
 }
 
 static void pcnet32_netif_start(struct net_device *dev)
 {
+	struct pcnet32_private *lp = netdev_priv(dev);
 	netif_wake_queue(dev);
-	netif_poll_enable(dev);
+#ifdef CONFIG_PCNET32_NAPI
+	napi_enable(&lp->napi);
+#endif
 }
 
 /*
@@ -816,7 +824,7 @@ static int pcnet32_set_ringparam(struct net_device *dev,
 	if ((1 << i) != lp->rx_ring_size)
 		pcnet32_realloc_rx_ring(dev, lp, i);
 
-	dev->weight = lp->rx_ring_size / 2;
+	lp->napi.weight = lp->rx_ring_size / 2;
 
 	if (netif_running(dev)) {
 		pcnet32_netif_start(dev);
@@ -1255,7 +1263,7 @@ static void pcnet32_rx_entry(struct net_device *dev,
 	return;
 }
 
-static int pcnet32_rx(struct net_device *dev, int quota)
+static int pcnet32_rx(struct net_device *dev, int budget)
 {
 	struct pcnet32_private *lp = netdev_priv(dev);
 	int entry = lp->cur_rx & lp->rx_mod_mask;
@@ -1263,7 +1271,7 @@ static int pcnet32_rx(struct net_device *dev, int quota)
 	int npackets = 0;
 
 	/* If we own the next entry, it's a new packet. Send it up. */
-	while (quota > npackets && (short)le16_to_cpu(rxp->status) >= 0) {
+	while (npackets < budget && (short)le16_to_cpu(rxp->status) >= 0) {
 		pcnet32_rx_entry(dev, lp, rxp, entry);
 		npackets += 1;
 		/*
@@ -1379,15 +1387,16 @@ static int pcnet32_tx(struct net_device *dev)
 }
 
 #ifdef CONFIG_PCNET32_NAPI
-static int pcnet32_poll(struct net_device *dev, int *budget)
+static int pcnet32_poll(struct napi_struct *napi, int budget)
 {
-	struct pcnet32_private *lp = netdev_priv(dev);
-	int quota = min(dev->quota, *budget);
+	struct pcnet32_private *lp = container_of(napi, struct pcnet32_private, napi);
+	struct net_device *dev = lp->dev;
 	unsigned long ioaddr = dev->base_addr;
 	unsigned long flags;
+	int work_done;
 	u16 val;
 
-	quota = pcnet32_rx(dev, quota);
+	work_done = pcnet32_rx(dev, budget);
 
 	spin_lock_irqsave(&lp->lock, flags);
 	if (pcnet32_tx(dev)) {
@@ -1399,28 +1408,22 @@ static int pcnet32_poll(struct net_device *dev, int *budget)
 	}
 	spin_unlock_irqrestore(&lp->lock, flags);
 
-	*budget -= quota;
-	dev->quota -= quota;
-
-	if (dev->quota == 0) {
-		return 1;
-	}
-
-	netif_rx_complete(dev);
-
-	spin_lock_irqsave(&lp->lock, flags);
+	if (work_done < budget) {
+		spin_lock_irqsave(&lp->lock, flags);
 
-	/* clear interrupt masks */
-	val = lp->a.read_csr(ioaddr, CSR3);
-	val &= 0x00ff;
-	lp->a.write_csr(ioaddr, CSR3, val);
+		__netif_rx_complete(dev, napi);
 
-	/* Set interrupt enable. */
-	lp->a.write_csr(ioaddr, CSR0, CSR0_INTEN);
-	mmiowb();
-	spin_unlock_irqrestore(&lp->lock, flags);
+		/* clear interrupt masks */
+		val = lp->a.read_csr(ioaddr, CSR3);
+		val &= 0x00ff;
+		lp->a.write_csr(ioaddr, CSR3, val);
 
-	return 0;
+		/* Set interrupt enable. */
+		lp->a.write_csr(ioaddr, CSR0, CSR0_INTEN);
+		mmiowb();
+		spin_unlock_irqrestore(&lp->lock, flags);
+	}
+	return work_done;
 }
 #endif
 
@@ -1815,6 +1818,8 @@ pcnet32_probe1(unsigned long ioaddr, int shared, struct pci_dev *pdev)
 	}
 	lp->pci_dev = pdev;
 
+	lp->dev = dev;
+
 	spin_lock_init(&lp->lock);
 
 	SET_MODULE_OWNER(dev);
@@ -1843,6 +1848,10 @@ pcnet32_probe1(unsigned long ioaddr, int shared, struct pci_dev *pdev)
 	lp->mii_if.mdio_read = mdio_read;
 	lp->mii_if.mdio_write = mdio_write;
 
+#ifdef CONFIG_PCNET32_NAPI
+	netif_napi_add(dev, &lp->napi, pcnet32_poll, lp->rx_ring_size / 2);
+#endif
+
 	if (fdx && !(lp->options & PCNET32_PORT_ASEL) &&
 	    ((cards_found >= MAX_UNITS) || full_duplex[cards_found]))
 		lp->options |= PCNET32_PORT_FD;
@@ -1953,10 +1962,6 @@ pcnet32_probe1(unsigned long ioaddr, int shared, struct pci_dev *pdev)
 	dev->ethtool_ops = &pcnet32_ethtool_ops;
 	dev->tx_timeout = pcnet32_tx_timeout;
 	dev->watchdog_timeo = (5 * HZ);
-	dev->weight = lp->rx_ring_size / 2;
-#ifdef CONFIG_PCNET32_NAPI
-	dev->poll = pcnet32_poll;
-#endif
 
 #ifdef CONFIG_NET_POLL_CONTROLLER
 	dev->poll_controller = pcnet32_poll_controller;
@@ -2276,6 +2281,10 @@ static int pcnet32_open(struct net_device *dev)
 		goto err_free_ring;
 	}
 
+#ifdef CONFIG_PCNET32_NAPI
+	napi_enable(&lp->napi);
+#endif
+
 	/* Re-initialize the PCNET32, and start it when done. */
 	lp->a.write_csr(ioaddr, 1, (lp->init_dma_addr & 0xffff));
 	lp->a.write_csr(ioaddr, 2, (lp->init_dma_addr >> 16));
@@ -2599,18 +2608,18 @@ pcnet32_interrupt(int irq, void *dev_id)
 			/* unlike for the lance, there is no restart needed */
 		}
 #ifdef CONFIG_PCNET32_NAPI
-		if (netif_rx_schedule_prep(dev)) {
+		if (netif_rx_schedule_prep(dev, &lp->napi)) {
 			u16 val;
 			/* set interrupt masks */
 			val = lp->a.read_csr(ioaddr, CSR3);
 			val |= 0x5f00;
 			lp->a.write_csr(ioaddr, CSR3, val);
 			mmiowb();
-			__netif_rx_schedule(dev);
+			__netif_rx_schedule(dev, &lp->napi);
 			break;
 		}
 #else
-		pcnet32_rx(dev, dev->weight);
+		pcnet32_rx(dev, lp->napi.weight);
 		if (pcnet32_tx(dev)) {
 			/* reset the chip to clear the error condition, then restart */
 			lp->a.reset(ioaddr);
@@ -2645,6 +2654,9 @@ static int pcnet32_close(struct net_device *dev)
 	del_timer_sync(&lp->watchdog_timer);
 
 	netif_stop_queue(dev);
+#ifdef CONFIG_PCNET32_NAPI
+	napi_disable(&lp->napi);
+#endif
 
 	spin_lock_irqsave(&lp->lock, flags);