[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, 25 insertions, 31 deletions

diff --git a/drivers/net/fs_enet/fs_enet-main.c b/drivers/net/fs_enet/fs_enet-main.c
index a4a2a0ea43d3..c509cb13222d 100644
--- a/drivers/net/fs_enet/fs_enet-main.c
+++ b/drivers/net/fs_enet/fs_enet-main.c
@@ -70,18 +70,16 @@ static void fs_set_multicast_list(struct net_device *dev)
 }
 
 /* NAPI receive function */
-static int fs_enet_rx_napi(struct net_device *dev, int *budget)
+static int fs_enet_rx_napi(struct napi_struct *napi, int budget)
 {
-        struct fs_enet_private *fep = netdev_priv(dev);
+        struct fs_enet_private *fep = container_of(napi, struct fs_enet_private, napi);
+        struct net_device *dev = to_net_dev(fep->dev);
         const struct fs_platform_info *fpi = fep->fpi;
         cbd_t *bdp;
         struct sk_buff *skb, *skbn, *skbt;
         int received = 0;
         u16 pkt_len, sc;
         int curidx;
-        int rx_work_limit = 0;  /* pacify gcc */
-
-        rx_work_limit = min(dev->quota, *budget);
 
         if (!netif_running(dev))
                 return 0;
@@ -96,7 +94,6 @@ static int fs_enet_rx_napi(struct net_device *dev, int *budget)
         (*fep->ops->napi_clear_rx_event)(dev);
 
         while (((sc = CBDR_SC(bdp)) & BD_ENET_RX_EMPTY) == 0) {
-
                 curidx = bdp - fep->rx_bd_base;
 
                 /*
@@ -136,11 +133,6 @@ static int fs_enet_rx_napi(struct net_device *dev, int *budget)
                         skbn = skb;
 
                 } else {
-
-                        /* napi, got packet but no quota */
-                        if (--rx_work_limit < 0)
-                                break;
-
                         skb = fep->rx_skbuff[curidx];
 
                         dma_unmap_single(fep->dev, CBDR_BUFADDR(bdp),
@@ -199,22 +191,19 @@ static int fs_enet_rx_napi(struct net_device *dev, int *budget)
                         bdp = fep->rx_bd_base;
 
                 (*fep->ops->rx_bd_done)(dev);
+
+                if (received >= budget)
+                        break;
         }
 
         fep->cur_rx = bdp;
 
-        dev->quota -= received;
-        *budget -= received;
-
-        if (rx_work_limit < 0)
-                return 1;       /* not done */
-
-        /* done */
-        netif_rx_complete(dev);
-
-        (*fep->ops->napi_enable_rx)(dev);
-
-        return 0;
+        if (received >= budget) {
+                /* done */
+                netif_rx_complete(dev, napi);
+                (*fep->ops->napi_enable_rx)(dev);
+        }
+        return received;
 }
 
 /* non NAPI receive function */
@@ -470,7 +459,7 @@ fs_enet_interrupt(int irq, void *dev_id)
                         if (!fpi->use_napi)
                                 fs_enet_rx_non_napi(dev);
                         else {
-                                napi_ok = netif_rx_schedule_prep(dev);
+                                napi_ok = napi_schedule_prep(&fep->napi);
 
                                 (*fep->ops->napi_disable_rx)(dev);
                                 (*fep->ops->clear_int_events)(dev, fep->ev_napi_rx);
@@ -478,7 +467,7 @@ fs_enet_interrupt(int irq, void *dev_id)
                                 /* NOTE: it is possible for FCCs in NAPI mode    */
                                 /* to submit a spurious interrupt while in poll  */
                                 if (napi_ok)
-                                        __netif_rx_schedule(dev);
+                                        __netif_rx_schedule(dev, &fep->napi);
                         }
                 }
 
@@ -799,18 +788,22 @@ static int fs_enet_open(struct net_device *dev)
         int r;
         int err;
 
+        napi_enable(&fep->napi);
+
         /* Install our interrupt handler. */
         r = fs_request_irq(dev, fep->interrupt, "fs_enet-mac", fs_enet_interrupt);
         if (r != 0) {
                 printk(KERN_ERR DRV_MODULE_NAME
                        ": %s Could not allocate FS_ENET IRQ!", dev->name);
+                napi_disable(&fep->napi);
                 return -EINVAL;
         }
 
         err = fs_init_phy(dev);
-        if(err)
+        if(err) {
+                napi_disable(&fep->napi);
                 return err;
-
+        }
         phy_start(fep->phydev);
 
         return 0;
@@ -823,6 +816,7 @@ static int fs_enet_close(struct net_device *dev)
 
         netif_stop_queue(dev);
         netif_carrier_off(dev);
+        napi_disable(&fep->napi);
         phy_stop(fep->phydev);
 
         spin_lock_irqsave(&fep->lock, flags);
@@ -1047,10 +1041,9 @@ static struct net_device *fs_init_instance(struct device *dev,
         ndev->stop = fs_enet_close;
         ndev->get_stats = fs_enet_get_stats;
         ndev->set_multicast_list = fs_set_multicast_list;
-        if (fpi->use_napi) {
-                ndev->poll = fs_enet_rx_napi;
-                ndev->weight = fpi->napi_weight;
-        }
+        netif_napi_add(ndev, &fep->napi,
+                       fs_enet_rx_napi, fpi->napi_weight);
+
         ndev->ethtool_ops = &fs_ethtool_ops;
         ndev->do_ioctl = fs_ioctl;
 
diff --git a/drivers/net/fs_enet/fs_enet.h b/drivers/net/fs_enet/fs_enet.h
index 569be225cd05..46d0606b1439 100644
--- a/drivers/net/fs_enet/fs_enet.h
+++ b/drivers/net/fs_enet/fs_enet.h
@@ -121,6 +121,7 @@ struct fs_enet_mii_bus {
 };
 
 struct fs_enet_private {
+        struct napi_struct napi;
         struct device *dev;     /* pointer back to the device (must be initialized first) */
         spinlock_t lock;        /* during all ops except TX pckt processing */
         spinlock_t tx_lock;     /* during fs_start_xmit and fs_tx         */