[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, 15 insertions, 20 deletions

diff --git a/drivers/net/s2io.c b/drivers/net/s2io.c
index 24feb00600ee..dd012322cdbe 100644
--- a/drivers/net/s2io.c
+++ b/drivers/net/s2io.c
@@ -2568,7 +2568,7 @@ static void free_rx_buffers(struct s2io_nic *sp)
 
 /**
  * s2io_poll - Rx interrupt handler for NAPI support
- * @dev : pointer to the device structure.
+ * @napi : pointer to the napi structure.
  * @budget : The number of packets that were budgeted to be processed
  * during  one pass through the 'Poll" function.
  * Description:
@@ -2579,9 +2579,10 @@ static void free_rx_buffers(struct s2io_nic *sp)
  * 0 on success and 1 if there are No Rx packets to be processed.
  */
 
-static int s2io_poll(struct net_device *dev, int *budget)
+static int s2io_poll(struct napi_struct *napi, int budget)
 {
-        struct s2io_nic *nic = dev->priv;
+        struct s2io_nic *nic = container_of(napi, struct s2io_nic, napi);
+        struct net_device *dev = nic->dev;
         int pkt_cnt = 0, org_pkts_to_process;
         struct mac_info *mac_control;
         struct config_param *config;
@@ -2592,9 +2593,7 @@ static int s2io_poll(struct net_device *dev, int *budget)
         mac_control = &nic->mac_control;
         config = &nic->config;
 
-        nic->pkts_to_process = *budget;
-        if (nic->pkts_to_process > dev->quota)
-                nic->pkts_to_process = dev->quota;
+        nic->pkts_to_process = budget;
         org_pkts_to_process = nic->pkts_to_process;
 
         writeq(S2IO_MINUS_ONE, &bar0->rx_traffic_int);
@@ -2608,12 +2607,8 @@ static int s2io_poll(struct net_device *dev, int *budget)
                         goto no_rx;
                 }
         }
-        if (!pkt_cnt)
-                pkt_cnt = 1;
 
-        dev->quota -= pkt_cnt;
-        *budget -= pkt_cnt;
-        netif_rx_complete(dev);
+        netif_rx_complete(dev, napi);
 
         for (i = 0; i < config->rx_ring_num; i++) {
                 if (fill_rx_buffers(nic, i) == -ENOMEM) {
@@ -2626,12 +2621,9 @@ static int s2io_poll(struct net_device *dev, int *budget)
         writeq(0x0, &bar0->rx_traffic_mask);
         readl(&bar0->rx_traffic_mask);
         atomic_dec(&nic->isr_cnt);
-        return 0;
+        return pkt_cnt;
 
 no_rx:
-        dev->quota -= pkt_cnt;
-        *budget -= pkt_cnt;
-
         for (i = 0; i < config->rx_ring_num; i++) {
                 if (fill_rx_buffers(nic, i) == -ENOMEM) {
                         DBG_PRINT(INFO_DBG, "%s:Out of memory", dev->name);
@@ -2640,7 +2632,7 @@ no_rx:
                 }
         }
         atomic_dec(&nic->isr_cnt);
-        return 1;
+        return pkt_cnt;
 }
 
 #ifdef CONFIG_NET_POLL_CONTROLLER
@@ -3809,6 +3801,8 @@ static int s2io_open(struct net_device *dev)
         netif_carrier_off(dev);
         sp->last_link_state = 0;
 
+        napi_enable(&sp->napi);
+
         /* Initialize H/W and enable interrupts */
         err = s2io_card_up(sp);
         if (err) {
@@ -3828,6 +3822,7 @@ static int s2io_open(struct net_device *dev)
         return 0;
 
 hw_init_failed:
+        napi_disable(&sp->napi);
         if (sp->intr_type == MSI_X) {
                 if (sp->entries) {
                         kfree(sp->entries);
@@ -3861,6 +3856,7 @@ static int s2io_close(struct net_device *dev)
         struct s2io_nic *sp = dev->priv;
 
         netif_stop_queue(dev);
+        napi_disable(&sp->napi);
         /* Reset card, kill tasklet and free Tx and Rx buffers. */
         s2io_card_down(sp);
 
@@ -4232,8 +4228,8 @@ static irqreturn_t s2io_isr(int irq, void *dev_id)
 
         if (napi) {
                 if (reason & GEN_INTR_RXTRAFFIC) {
-                        if ( likely ( netif_rx_schedule_prep(dev)) ) {
-                                __netif_rx_schedule(dev);
+                        if (likely (netif_rx_schedule_prep(dev, &sp->napi))) {
+                                __netif_rx_schedule(dev, &sp->napi);
                                 writeq(S2IO_MINUS_ONE, &bar0->rx_traffic_mask);
                         }
                         else
@@ -7215,8 +7211,7 @@ s2io_init_nic(struct pci_dev *pdev, const struct pci_device_id *pre)
          * will use eth_mac_addr() for  dev->set_mac_address
          * mac address will be set every time dev->open() is called
          */
-        dev->poll = s2io_poll;
-        dev->weight = 32;
+        netif_napi_add(dev, &sp->napi, s2io_poll, 32);
 
 #ifdef CONFIG_NET_POLL_CONTROLLER
         dev->poll_controller = s2io_netpoll;