[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, 19 insertions, 20 deletions

diff --git a/drivers/net/netxen/netxen_nic_main.c b/drivers/net/netxen/netxen_nic_main.c
index 3122d0101638..a10bbefbdadd 100644
--- a/drivers/net/netxen/netxen_nic_main.c
+++ b/drivers/net/netxen/netxen_nic_main.c
@@ -68,7 +68,7 @@ static void netxen_tx_timeout(struct net_device *netdev);
 static void netxen_tx_timeout_task(struct work_struct *work);
 static void netxen_watchdog(unsigned long);
 static int netxen_handle_int(struct netxen_adapter *, struct net_device *);
-static int netxen_nic_poll(struct net_device *dev, int *budget);
+static int netxen_nic_poll(struct napi_struct *napi, int budget);
 #ifdef CONFIG_NET_POLL_CONTROLLER
 static void netxen_nic_poll_controller(struct net_device *netdev);
 #endif
@@ -402,6 +402,9 @@ netxen_nic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
         adapter->netdev  = netdev;
         adapter->pdev    = pdev;
 
+        netif_napi_add(netdev, &adapter->napi,
+                       netxen_nic_poll, NETXEN_NETDEV_WEIGHT);
+
         /* this will be read from FW later */
         adapter->intr_scheme = -1;
 
@@ -422,8 +425,6 @@ netxen_nic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
         netxen_nic_change_mtu(netdev, netdev->mtu);
 
         SET_ETHTOOL_OPS(netdev, &netxen_nic_ethtool_ops);
-        netdev->poll = netxen_nic_poll;
-        netdev->weight = NETXEN_NETDEV_WEIGHT;
 #ifdef CONFIG_NET_POLL_CONTROLLER
         netdev->poll_controller = netxen_nic_poll_controller;
 #endif
@@ -885,6 +886,8 @@ static int netxen_nic_open(struct net_device *netdev)
         if (!adapter->driver_mismatch)
                 mod_timer(&adapter->watchdog_timer, jiffies);
 
+        napi_enable(&adapter->napi);
+
         netxen_nic_enable_int(adapter);
 
         /* Done here again so that even if phantom sw overwrote it,
@@ -894,6 +897,7 @@ static int netxen_nic_open(struct net_device *netdev)
             del_timer_sync(&adapter->watchdog_timer);
                 printk(KERN_ERR "%s: Failed to initialize port %d\n",
                                 netxen_nic_driver_name, adapter->portnum);
+                napi_disable(&adapter->napi);
                 return -EIO;
         }
         if (adapter->macaddr_set)
@@ -923,6 +927,7 @@ static int netxen_nic_close(struct net_device *netdev)
 
         netif_carrier_off(netdev);
         netif_stop_queue(netdev);
+        napi_disable(&adapter->napi);
 
         netxen_nic_disable_int(adapter);
 
@@ -1243,11 +1248,11 @@ netxen_handle_int(struct netxen_adapter *adapter, struct net_device *netdev)
         netxen_nic_disable_int(adapter);
 
         if (netxen_nic_rx_has_work(adapter) || netxen_nic_tx_has_work(adapter)) {
-                if (netif_rx_schedule_prep(netdev)) {
+                if (netif_rx_schedule_prep(netdev, &adapter->napi)) {
                         /*
                          * Interrupts are already disabled.
                          */
-                        __netif_rx_schedule(netdev);
+                        __netif_rx_schedule(netdev, &adapter->napi);
                 } else {
                         static unsigned int intcount = 0;
                         if ((++intcount & 0xfff) == 0xfff)
@@ -1305,14 +1310,13 @@ irqreturn_t netxen_intr(int irq, void *data)
         return IRQ_HANDLED;
 }
 
-static int netxen_nic_poll(struct net_device *netdev, int *budget)
+static int netxen_nic_poll(struct napi_struct *napi, int budget)
 {
-        struct netxen_adapter *adapter = netdev_priv(netdev);
-        int work_to_do = min(*budget, netdev->quota);
+        struct netxen_adapter *adapter = container_of(napi, struct netxen_adapter, napi);
+        struct net_device *netdev = adapter->netdev;
         int done = 1;
         int ctx;
-        int this_work_done;
-        int work_done = 0;
+        int work_done;
 
         DPRINTK(INFO, "polling for %d descriptors\n", *budget);
 
@@ -1330,16 +1334,11 @@ static int netxen_nic_poll(struct net_device *netdev, int *budget)
                  * packets are on one context, it gets only half of the quota,
                  * and ends up not processing it.
                  */
-                this_work_done = netxen_process_rcv_ring(adapter, ctx,
-                                                         work_to_do /
-                                                         MAX_RCV_CTX);
-                work_done += this_work_done;
+                work_done += netxen_process_rcv_ring(adapter, ctx,
+                                                     budget / MAX_RCV_CTX);
         }
 
-        netdev->quota -= work_done;
-        *budget -= work_done;
-
-        if (work_done >= work_to_do && netxen_nic_rx_has_work(adapter) != 0)
+        if (work_done >= budget && netxen_nic_rx_has_work(adapter) != 0)
                 done = 0;
 
         if (netxen_process_cmd_ring((unsigned long)adapter) == 0)
@@ -1348,11 +1347,11 @@ static int netxen_nic_poll(struct net_device *netdev, int *budget)
         DPRINTK(INFO, "new work_done: %d work_to_do: %d\n",
                 work_done, work_to_do);
         if (done) {
-                netif_rx_complete(netdev);
+                netif_rx_complete(netdev, napi);
                 netxen_nic_enable_int(adapter);
         }
 
-        return !done;
+        return work_done;
 }
 
 #ifdef CONFIG_NET_POLL_CONTROLLER