[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, 34 insertions, 38 deletions

diff --git a/drivers/net/arm/ep93xx_eth.c b/drivers/net/arm/ep93xx_eth.c
index f6ece1d43f6e..7f016f3d5bf0 100644
--- a/drivers/net/arm/ep93xx_eth.c
+++ b/drivers/net/arm/ep93xx_eth.c
@@ -169,6 +169,9 @@ struct ep93xx_priv
         spinlock_t              tx_pending_lock;
         unsigned int            tx_pending;
 
+        struct net_device       *dev;
+        struct napi_struct      napi;
+
         struct net_device_stats stats;
 
         struct mii_if_info      mii;
@@ -190,15 +193,11 @@ static struct net_device_stats *ep93xx_get_stats(struct net_device *dev)
         return &(ep->stats);
 }
 
-static int ep93xx_rx(struct net_device *dev, int *budget)
+static int ep93xx_rx(struct net_device *dev, int processed, int budget)
 {
         struct ep93xx_priv *ep = netdev_priv(dev);
-        int rx_done;
-        int processed;
 
-        rx_done = 0;
-        processed = 0;
-        while (*budget > 0) {
+        while (processed < budget) {
                 int entry;
                 struct ep93xx_rstat *rstat;
                 u32 rstat0;
@@ -211,10 +210,8 @@ static int ep93xx_rx(struct net_device *dev, int *budget)
 
                 rstat0 = rstat->rstat0;
                 rstat1 = rstat->rstat1;
-                if (!(rstat0 & RSTAT0_RFP) || !(rstat1 & RSTAT1_RFP)) {
-                        rx_done = 1;
+                if (!(rstat0 & RSTAT0_RFP) || !(rstat1 & RSTAT1_RFP))
                         break;
-                }
 
                 rstat->rstat0 = 0;
                 rstat->rstat1 = 0;
@@ -275,8 +272,6 @@ static int ep93xx_rx(struct net_device *dev, int *budget)
 err:
                 ep->rx_pointer = (entry + 1) & (RX_QUEUE_ENTRIES - 1);
                 processed++;
-                dev->quota--;
-                (*budget)--;
         }
 
         if (processed) {
@@ -284,7 +279,7 @@ err:
                 wrw(ep, REG_RXSTSENQ, processed);
         }
 
-        return !rx_done;
+        return processed;
 }
 
 static int ep93xx_have_more_rx(struct ep93xx_priv *ep)
@@ -293,36 +288,32 @@ static int ep93xx_have_more_rx(struct ep93xx_priv *ep)
         return !!((rstat->rstat0 & RSTAT0_RFP) && (rstat->rstat1 & RSTAT1_RFP));
 }
 
-static int ep93xx_poll(struct net_device *dev, int *budget)
+static int ep93xx_poll(struct napi_struct *napi, int budget)
 {
-        struct ep93xx_priv *ep = netdev_priv(dev);
-
-        /*
-         * @@@ Have to stop polling if device is downed while we
-         * are polling.
-         */
+        struct ep93xx_priv *ep = container_of(napi, struct ep93xx_priv, napi);
+        struct net_device *dev = ep->dev;
+        int rx = 0;
 
 poll_some_more:
-        if (ep93xx_rx(dev, budget))
-                return 1;
-
-        netif_rx_complete(dev);
-
-        spin_lock_irq(&ep->rx_lock);
-        wrl(ep, REG_INTEN, REG_INTEN_TX | REG_INTEN_RX);
-        if (ep93xx_have_more_rx(ep)) {
-                wrl(ep, REG_INTEN, REG_INTEN_TX);
-                wrl(ep, REG_INTSTSP, REG_INTSTS_RX);
+        rx = ep93xx_rx(dev, rx, budget);
+        if (rx < budget) {
+                int more = 0;
+
+                spin_lock_irq(&ep->rx_lock);
+                __netif_rx_complete(dev, napi);
+                wrl(ep, REG_INTEN, REG_INTEN_TX | REG_INTEN_RX);
+                if (ep93xx_have_more_rx(ep)) {
+                        wrl(ep, REG_INTEN, REG_INTEN_TX);
+                        wrl(ep, REG_INTSTSP, REG_INTSTS_RX);
+                        more = 1;
+                }
                 spin_unlock_irq(&ep->rx_lock);
 
-                if (netif_rx_reschedule(dev, 0))
+                if (more && netif_rx_reschedule(dev, napi))
                         goto poll_some_more;
-
-                return 0;
         }
-        spin_unlock_irq(&ep->rx_lock);
 
-        return 0;
+        return rx;
 }
 
 static int ep93xx_xmit(struct sk_buff *skb, struct net_device *dev)
@@ -426,9 +417,9 @@ static irqreturn_t ep93xx_irq(int irq, void *dev_id)
 
         if (status & REG_INTSTS_RX) {
                 spin_lock(&ep->rx_lock);
-                if (likely(__netif_rx_schedule_prep(dev))) {
+                if (likely(__netif_rx_schedule_prep(dev, &ep->napi))) {
                         wrl(ep, REG_INTEN, REG_INTEN_TX);
-                        __netif_rx_schedule(dev);
+                        __netif_rx_schedule(dev, &ep->napi);
                 }
                 spin_unlock(&ep->rx_lock);
         }
@@ -648,7 +639,10 @@ static int ep93xx_open(struct net_device *dev)
                         dev->dev_addr[4], dev->dev_addr[5]);
         }
 
+        napi_enable(&ep->napi);
+
         if (ep93xx_start_hw(dev)) {
+                napi_disable(&ep->napi);
                 ep93xx_free_buffers(ep);
                 return -EIO;
         }
@@ -662,6 +656,7 @@ static int ep93xx_open(struct net_device *dev)
 
         err = request_irq(ep->irq, ep93xx_irq, IRQF_SHARED, dev->name, dev);
         if (err) {
+                napi_disable(&ep->napi);
                 ep93xx_stop_hw(dev);
                 ep93xx_free_buffers(ep);
                 return err;
@@ -678,6 +673,7 @@ static int ep93xx_close(struct net_device *dev)
 {
         struct ep93xx_priv *ep = netdev_priv(dev);
 
+        napi_disable(&ep->napi);
         netif_stop_queue(dev);
 
         wrl(ep, REG_GIINTMSK, 0);
@@ -788,14 +784,12 @@ struct net_device *ep93xx_dev_alloc(struct ep93xx_eth_data *data)
 
         dev->get_stats = ep93xx_get_stats;
         dev->ethtool_ops = &ep93xx_ethtool_ops;
-        dev->poll = ep93xx_poll;
         dev->hard_start_xmit = ep93xx_xmit;
         dev->open = ep93xx_open;
         dev->stop = ep93xx_close;
         dev->do_ioctl = ep93xx_ioctl;
 
         dev->features |= NETIF_F_SG | NETIF_F_HW_CSUM;
-        dev->weight = 64;
 
         return dev;
 }
@@ -847,6 +841,8 @@ static int ep93xx_eth_probe(struct platform_device *pdev)
                 goto err_out;
         }
         ep = netdev_priv(dev);
+        ep->dev = dev;
+        netif_napi_add(dev, &ep->napi, ep93xx_poll, 64);
 
         platform_set_drvdata(pdev, dev);