[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>

2 files changed, 31 insertions, 30 deletions

diff --git a/drivers/net/fec_8xx/fec_8xx.h b/drivers/net/fec_8xx/fec_8xx.h
index 5af60b0f9208..f3b1c6fbba8b 100644
--- a/drivers/net/fec_8xx/fec_8xx.h
+++ b/drivers/net/fec_8xx/fec_8xx.h
@@ -105,6 +105,8 @@ struct fec;
 struct fec_enet_private {
         spinlock_t lock;        /* during all ops except TX pckt processing */
         spinlock_t tx_lock;     /* during fec_start_xmit and fec_tx         */
+        struct net_device *dev;
+        struct napi_struct napi;
         int fecno;
         struct fec *fecp;
         const struct fec_platform_info *fpi;
diff --git a/drivers/net/fec_8xx/fec_main.c b/drivers/net/fec_8xx/fec_main.c
index e5502af5b8e2..6348fb93ca9c 100644
--- a/drivers/net/fec_8xx/fec_main.c
+++ b/drivers/net/fec_8xx/fec_main.c
@@ -465,9 +465,9 @@ void fec_stop(struct net_device *dev)
 }
 
 /* common receive function */
-static int fec_enet_rx_common(struct net_device *dev, int *budget)
+static int fec_enet_rx_common(struct fec_enet_private *ep,
+                              struct net_device *dev, int budget)
 {
-        struct fec_enet_private *fep = netdev_priv(dev);
         fec_t *fecp = fep->fecp;
         const struct fec_platform_info *fpi = fep->fpi;
         cbd_t *bdp;
@@ -475,11 +475,8 @@ static int fec_enet_rx_common(struct net_device *dev, int *budget)
         int received = 0;
         __u16 pkt_len, sc;
         int curidx;
-        int rx_work_limit;
 
         if (fpi->use_napi) {
-                rx_work_limit = min(dev->quota, *budget);
-
                 if (!netif_running(dev))
                         return 0;
         }
@@ -530,11 +527,6 @@ static int fec_enet_rx_common(struct net_device *dev, int *budget)
                         BUG_ON(skbn == NULL);
 
                 } else {
-
-                        /* napi, got packet but no quota */
-                        if (fpi->use_napi && --rx_work_limit < 0)
-                                break;
-
                         skb = fep->rx_skbuff[curidx];
                         BUG_ON(skb == NULL);
 
@@ -599,25 +591,24 @@ static int fec_enet_rx_common(struct net_device *dev, int *budget)
                  * able to keep up at the expense of system resources.
                  */
                 FW(fecp, r_des_active, 0x01000000);
+
+                if (received >= budget)
+                        break;
+
         }
 
         fep->cur_rx = bdp;
 
         if (fpi->use_napi) {
-                dev->quota -= received;
-                *budget -= received;
-
-                if (rx_work_limit < 0)
-                        return 1;       /* not done */
+                if (received < budget) {
+                        netif_rx_complete(dev, &fep->napi);
 
-                /* done */
-                netif_rx_complete(dev);
-
-                /* enable RX interrupt bits */
-                FS(fecp, imask, FEC_ENET_RXF | FEC_ENET_RXB);
+                        /* enable RX interrupt bits */
+                        FS(fecp, imask, FEC_ENET_RXF | FEC_ENET_RXB);
+                }
         }
 
-        return 0;
+        return received;
 }
 
 static void fec_enet_tx(struct net_device *dev)
@@ -743,12 +734,12 @@ fec_enet_interrupt(int irq, void *dev_id)
 
                 if ((int_events & FEC_ENET_RXF) != 0) {
                         if (!fpi->use_napi)
-                                fec_enet_rx_common(dev, NULL);
+                                fec_enet_rx_common(fep, dev, ~0);
                         else {
-                                if (netif_rx_schedule_prep(dev)) {
+                                if (netif_rx_schedule_prep(dev, &fep->napi)) {
                                         /* disable rx interrupts */
                                         FC(fecp, imask, FEC_ENET_RXF | FEC_ENET_RXB);
-                                        __netif_rx_schedule(dev);
+                                        __netif_rx_schedule(dev, &fep->napi);
                                 } else {
                                         printk(KERN_ERR DRV_MODULE_NAME
                                                ": %s driver bug! interrupt while in poll!\n",
@@ -893,10 +884,13 @@ static int fec_enet_open(struct net_device *dev)
         const struct fec_platform_info *fpi = fep->fpi;
         unsigned long flags;
 
+        napi_enable(&fep->napi);
+
         /* Install our interrupt handler. */
         if (request_irq(fpi->fec_irq, fec_enet_interrupt, 0, "fec", dev) != 0) {
                 printk(KERN_ERR DRV_MODULE_NAME
                        ": %s Could not allocate FEC IRQ!", dev->name);
+                napi_disable(&fep->napi);
                 return -EINVAL;
         }
 
@@ -907,6 +901,7 @@ static int fec_enet_open(struct net_device *dev)
                 printk(KERN_ERR DRV_MODULE_NAME
                        ": %s Could not allocate PHY IRQ!", dev->name);
                 free_irq(fpi->fec_irq, dev);
+                napi_disable(&fep->napi);
                 return -EINVAL;
         }
 
@@ -932,6 +927,7 @@ static int fec_enet_close(struct net_device *dev)
         unsigned long flags;
 
         netif_stop_queue(dev);
+        napi_disable(&fep->napi);
         netif_carrier_off(dev);
 
         if (fpi->use_mdio)
@@ -955,9 +951,12 @@ static struct net_device_stats *fec_enet_get_stats(struct net_device *dev)
         return &fep->stats;
 }
 
-static int fec_enet_poll(struct net_device *dev, int *budget)
+static int fec_enet_poll(struct napi_struct *napi, int budget)
 {
-        return fec_enet_rx_common(dev, budget);
+        struct fec_enet_private *fep = container_of(napi, struct fec_enet_private, napi);
+        struct net_device *dev = fep->dev;
+
+        return fec_enet_rx_common(fep, dev, budget);
 }
 
 /*************************************************************************/
@@ -1107,6 +1106,7 @@ int fec_8xx_init_one(const struct fec_platform_info *fpi,
         SET_MODULE_OWNER(dev);
 
         fep = netdev_priv(dev);
+        fep->dev = dev;
 
         /* partial reset of FEC */
         fec_whack_reset(fecp);
@@ -1172,10 +1172,9 @@ int fec_8xx_init_one(const struct fec_platform_info *fpi,
         dev->get_stats = fec_enet_get_stats;
         dev->set_multicast_list = fec_set_multicast_list;
         dev->set_mac_address = fec_set_mac_address;
-        if (fpi->use_napi) {
-                dev->poll = fec_enet_poll;
-                dev->weight = fpi->napi_weight;
-        }
+        netif_napi_add(dev, &fec->napi,
+                       fec_enet_poll, fpi->napi_weight);
+
         dev->ethtool_ops = &fec_ethtool_ops;
         dev->do_ioctl = fec_ioctl;