[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, 21 insertions, 20 deletions

diff --git a/drivers/net/8139cp.c b/drivers/net/8139cp.c
index a79f28c..7f18ca2 100644
--- a/drivers/net/8139cp.c
+++ b/drivers/net/8139cp.c
@@ -334,6 +334,8 @@ struct cp_private {
 	spinlock_t		lock;
 	u32			msg_enable;
 
+	struct napi_struct	napi;
+
 	struct pci_dev		*pdev;
 	u32			rx_config;
 	u16			cpcmd;
@@ -501,12 +503,12 @@ static inline unsigned int cp_rx_csum_ok (u32 status)
 	return 0;
 }
 
-static int cp_rx_poll (struct net_device *dev, int *budget)
+static int cp_rx_poll(struct napi_struct *napi, int budget)
 {
-	struct cp_private *cp = netdev_priv(dev);
-	unsigned rx_tail = cp->rx_tail;
-	unsigned rx_work = dev->quota;
-	unsigned rx;
+	struct cp_private *cp = container_of(napi, struct cp_private, napi);
+	struct net_device *dev = cp->dev;
+	unsigned int rx_tail = cp->rx_tail;
+	int rx;
 
 rx_status_loop:
 	rx = 0;
@@ -588,33 +590,28 @@ rx_next:
 			desc->opts1 = cpu_to_le32(DescOwn | cp->rx_buf_sz);
 		rx_tail = NEXT_RX(rx_tail);
 
-		if (!rx_work--)
+		if (rx >= budget)
 			break;
 	}
 
 	cp->rx_tail = rx_tail;
 
-	dev->quota -= rx;
-	*budget -= rx;
-
 	/* if we did not reach work limit, then we're done with
 	 * this round of polling
 	 */
-	if (rx_work) {
+	if (rx < budget) {
 		unsigned long flags;
 
 		if (cpr16(IntrStatus) & cp_rx_intr_mask)
 			goto rx_status_loop;
 
-		local_irq_save(flags);
+		spin_lock_irqsave(&cp->lock, flags);
 		cpw16_f(IntrMask, cp_intr_mask);
-		__netif_rx_complete(dev);
-		local_irq_restore(flags);
-
-		return 0;	/* done */
+		__netif_rx_complete(dev, napi);
+		spin_unlock_irqrestore(&cp->lock, flags);
 	}
 
-	return 1;		/* not done */
+	return rx;
 }
 
 static irqreturn_t cp_interrupt (int irq, void *dev_instance)
@@ -647,9 +644,9 @@ static irqreturn_t cp_interrupt (int irq, void *dev_instance)
 	}
 
 	if (status & (RxOK | RxErr | RxEmpty | RxFIFOOvr))
-		if (netif_rx_schedule_prep(dev)) {
+		if (netif_rx_schedule_prep(dev, &cp->napi)) {
 			cpw16_f(IntrMask, cp_norx_intr_mask);
-			__netif_rx_schedule(dev);
+			__netif_rx_schedule(dev, &cp->napi);
 		}
 
 	if (status & (TxOK | TxErr | TxEmpty | SWInt))
@@ -1175,6 +1172,8 @@ static int cp_open (struct net_device *dev)
 	if (rc)
 		return rc;
 
+	napi_enable(&cp->napi);
+
 	cp_init_hw(cp);
 
 	rc = request_irq(dev->irq, cp_interrupt, IRQF_SHARED, dev->name, dev);
@@ -1188,6 +1187,7 @@ static int cp_open (struct net_device *dev)
 	return 0;
 
 err_out_hw:
+	napi_disable(&cp->napi);
 	cp_stop_hw(cp);
 	cp_free_rings(cp);
 	return rc;
@@ -1198,6 +1198,8 @@ static int cp_close (struct net_device *dev)
 	struct cp_private *cp = netdev_priv(dev);
 	unsigned long flags;
 
+	napi_disable(&cp->napi);
+
 	if (netif_msg_ifdown(cp))
 		printk(KERN_DEBUG "%s: disabling interface\n", dev->name);
 
@@ -1933,11 +1935,10 @@ static int cp_init_one (struct pci_dev *pdev, const struct pci_device_id *ent)
 	dev->hard_start_xmit = cp_start_xmit;
 	dev->get_stats = cp_get_stats;
 	dev->do_ioctl = cp_ioctl;
-	dev->poll = cp_rx_poll;
 #ifdef CONFIG_NET_POLL_CONTROLLER
 	dev->poll_controller = cp_poll_controller;
 #endif
-	dev->weight = 16;	/* arbitrary? from NAPI_HOWTO.txt. */
+	netif_napi_add(dev, &cp->napi, cp_rx_poll, 16);
 #ifdef BROKEN
 	dev->change_mtu = cp_change_mtu;
 #endif