[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, 17 insertions, 20 deletions

diff --git a/drivers/net/e100.c b/drivers/net/e100.c
index 280313b9b069..e25f5ec2b279 100644
--- a/drivers/net/e100.c
+++ b/drivers/net/e100.c
@@ -539,6 +539,7 @@ struct nic {
         struct csr __iomem *csr;
         enum scb_cmd_lo cuc_cmd;
         unsigned int cbs_avail;
+        struct napi_struct napi;
         struct cb *cbs;
         struct cb *cb_to_use;
         struct cb *cb_to_send;
@@ -1974,35 +1975,31 @@ static irqreturn_t e100_intr(int irq, void *dev_id)
         if(stat_ack & stat_ack_rnr)
                 nic->ru_running = RU_SUSPENDED;
 
-        if(likely(netif_rx_schedule_prep(netdev))) {
+        if(likely(netif_rx_schedule_prep(netdev, &nic->napi))) {
                 e100_disable_irq(nic);
-                __netif_rx_schedule(netdev);
+                __netif_rx_schedule(netdev, &nic->napi);
         }
 
         return IRQ_HANDLED;
 }
 
-static int e100_poll(struct net_device *netdev, int *budget)
+static int e100_poll(struct napi_struct *napi, int budget)
 {
-        struct nic *nic = netdev_priv(netdev);
-        unsigned int work_to_do = min(netdev->quota, *budget);
-        unsigned int work_done = 0;
+        struct nic *nic = container_of(napi, struct nic, napi);
+        struct net_device *netdev = nic->netdev;
+        int work_done = 0;
         int tx_cleaned;
 
-        e100_rx_clean(nic, &work_done, work_to_do);
+        e100_rx_clean(nic, &work_done, budget);
         tx_cleaned = e100_tx_clean(nic);
 
         /* If no Rx and Tx cleanup work was done, exit polling mode. */
         if((!tx_cleaned && (work_done == 0)) || !netif_running(netdev)) {
-                netif_rx_complete(netdev);
+                netif_rx_complete(netdev, napi);
                 e100_enable_irq(nic);
-                return 0;
         }
 
-        *budget -= work_done;
-        netdev->quota -= work_done;
-
-        return 1;
+        return work_done;
 }
 
 #ifdef CONFIG_NET_POLL_CONTROLLER
@@ -2071,7 +2068,7 @@ static int e100_up(struct nic *nic)
                 nic->netdev->name, nic->netdev)))
                 goto err_no_irq;
         netif_wake_queue(nic->netdev);
-        netif_poll_enable(nic->netdev);
+        napi_enable(&nic->napi);
         /* enable ints _after_ enabling poll, preventing a race between
          * disable ints+schedule */
         e100_enable_irq(nic);
@@ -2089,7 +2086,7 @@ err_rx_clean_list:
 static void e100_down(struct nic *nic)
 {
         /* wait here for poll to complete */
-        netif_poll_disable(nic->netdev);
+        napi_disable(&nic->napi);
         netif_stop_queue(nic->netdev);
         e100_hw_reset(nic);
         free_irq(nic->pdev->irq, nic->netdev);
@@ -2572,14 +2569,13 @@ static int __devinit e100_probe(struct pci_dev *pdev,
         SET_ETHTOOL_OPS(netdev, &e100_ethtool_ops);
         netdev->tx_timeout = e100_tx_timeout;
         netdev->watchdog_timeo = E100_WATCHDOG_PERIOD;
-        netdev->poll = e100_poll;
-        netdev->weight = E100_NAPI_WEIGHT;
 #ifdef CONFIG_NET_POLL_CONTROLLER
         netdev->poll_controller = e100_netpoll;
 #endif
         strncpy(netdev->name, pci_name(pdev), sizeof(netdev->name) - 1);
 
         nic = netdev_priv(netdev);
+        netif_napi_add(netdev, &nic->napi, e100_poll, E100_NAPI_WEIGHT);
         nic->netdev = netdev;
         nic->pdev = pdev;
         nic->msg_enable = (1 << debug) - 1;
@@ -2733,7 +2729,7 @@ static int e100_suspend(struct pci_dev *pdev, pm_message_t state)
         struct nic *nic = netdev_priv(netdev);
 
         if (netif_running(netdev))
-                netif_poll_disable(nic->netdev);
+                napi_disable(&nic->napi);
         del_timer_sync(&nic->watchdog);
         netif_carrier_off(nic->netdev);
         netif_device_detach(netdev);
@@ -2779,7 +2775,7 @@ static void e100_shutdown(struct pci_dev *pdev)
         struct nic *nic = netdev_priv(netdev);
 
         if (netif_running(netdev))
-                netif_poll_disable(nic->netdev);
+                napi_disable(&nic->napi);
         del_timer_sync(&nic->watchdog);
         netif_carrier_off(nic->netdev);
 
@@ -2804,12 +2800,13 @@ static void e100_shutdown(struct pci_dev *pdev)
 static pci_ers_result_t e100_io_error_detected(struct pci_dev *pdev, pci_channel_state_t state)
 {
         struct net_device *netdev = pci_get_drvdata(pdev);
+        struct nic *nic = netdev_priv(netdev);
 
         /* Similar to calling e100_down(), but avoids adpater I/O. */
         netdev->stop(netdev);
 
         /* Detach; put netif into state similar to hotplug unplug. */
-        netif_poll_enable(netdev);
+        napi_enable(&nic->napi);
         netif_device_detach(netdev);
         pci_disable_device(pdev);