netpoll: various bugfixes

@@ -639,6 +639,7 @@ int netpoll_setup(struct netpoll *np)
 		if (!npinfo)
 			goto release;
 
+		npinfo->rx_flags = 0;
 		npinfo->rx_np = NULL;
 		npinfo->poll_lock = SPIN_LOCK_UNLOCKED;
 		npinfo->poll_owner = -1;

Index: l/net/core/netpoll.c
===================================================================
@@ -353,11 +353,8 @@ static void arp_reply(struct sk_buff *sk
 	struct sk_buff *send_skb;
 	struct netpoll *np = NULL;
 
-	spin_lock_irqsave(&npinfo->rx_lock, flags);
 	if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
 		np = npinfo->rx_np;
-	spin_unlock_irqrestore(&npinfo->rx_lock, flags);
-
 	if (!np)
 		return;
 

Index: l/drivers/net/e1000/e1000_main.c
===================================================================
@@ -3789,6 +3789,7 @@ e1000_netpoll(struct net_device *netdev)
 	struct e1000_adapter *adapter = netdev_priv(netdev);
 	disable_irq(adapter->pdev->irq);
 	e1000_intr(adapter->pdev->irq, netdev, NULL);
+	e1000_clean_tx_irq(adapter);
 	enable_irq(adapter->pdev->irq);
 }
 #endif

Index: l/net/core/netpoll.c
===================================================================
@@ -248,14 +248,14 @@ static void netpoll_send_skb(struct netp
 	int status;
 	struct netpoll_info *npinfo;
 
-repeat:
-	if(!np || !np->dev || !netif_running(np->dev)) {
+	if (!np || !np->dev || !netif_running(np->dev)) {
 		__kfree_skb(skb);
 		return;
 	}
 
-	/* avoid recursion */
 	npinfo = np->dev->npinfo;
+
+	/* avoid recursion */
 	if (npinfo->poll_owner == smp_processor_id() ||
 	    np->dev->xmit_lock_owner == smp_processor_id()) {
 		if (np->drop)

@@ -265,29 +265,31 @@ repeat:
 		return;
 	}
 
-	spin_lock(&np->dev->xmit_lock);
-	np->dev->xmit_lock_owner = smp_processor_id();
+	while (1) {
+		spin_lock(&np->dev->xmit_lock);
+		np->dev->xmit_lock_owner = smp_processor_id();
+
+		/*
+		 * network drivers do not expect to be called if the queue is
+		 * stopped.
+		 */
+		if (netif_queue_stopped(np->dev)) {
+			np->dev->xmit_lock_owner = -1;
+			spin_unlock(&np->dev->xmit_lock);
+			netpoll_poll(np);
+			continue;
+		}
 
-	/*
-	 * network drivers do not expect to be called if the queue is
-	 * stopped.
-	 */
-	if (netif_queue_stopped(np->dev)) {
+		status = np->dev->hard_start_xmit(skb, np->dev);
 		np->dev->xmit_lock_owner = -1;
 		spin_unlock(&np->dev->xmit_lock);
 
-		netpoll_poll(np);
-		goto repeat;
-	}
-
-	status = np->dev->hard_start_xmit(skb, np->dev);
-	np->dev->xmit_lock_owner = -1;
-	spin_unlock(&np->dev->xmit_lock);
+		/* success */
+		if(!status)
+			return;
 
-	/* transmit busy */
-	if(status) {
+		/* transmit busy */
 		netpoll_poll(np);
-		goto repeat;
 	}
 }
 

Index: lhg/net/core/netpoll.c
===================================================================
@@ -33,6 +33,7 @@
 #define MAX_UDP_CHUNK 1460
 #define MAX_SKBS 32
 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
+#define MAX_RETRIES 20000
 
 static DEFINE_SPINLOCK(skb_list_lock);
 static int nr_skbs;

@@ -265,7 +266,8 @@ static void netpoll_send_skb(struct netp
 		return;
 	}
 
-	while (1) {
+	do {
+		npinfo->tries--;
 		spin_lock(&np->dev->xmit_lock);
 		np->dev->xmit_lock_owner = smp_processor_id();
 

@@ -277,6 +279,7 @@ static void netpoll_send_skb(struct netp
 			np->dev->xmit_lock_owner = -1;
 			spin_unlock(&np->dev->xmit_lock);
 			netpoll_poll(np);
+			udelay(50);
 			continue;
 		}
 

@@ -285,12 +288,15 @@ static void netpoll_send_skb(struct netp
 		spin_unlock(&np->dev->xmit_lock);
 
 		/* success */
-		if(!status)
+		if(!status) {
+			npinfo->tries = MAX_RETRIES; /* reset */
 			return;
+		}
 
 		/* transmit busy */
 		netpoll_poll(np);
-	}
+		udelay(50);
+	} while (npinfo->tries > 0);
 }
 
 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)

@@ -642,6 +648,7 @@ int netpoll_setup(struct netpoll *np)
 		npinfo->rx_np = NULL;
 		npinfo->poll_lock = SPIN_LOCK_UNLOCKED;
 		npinfo->poll_owner = -1;
+		npinfo->tries = MAX_RETRIES;
 		npinfo->rx_lock = SPIN_LOCK_UNLOCKED;
 	} else
 		npinfo = ndev->npinfo;

Index: lhg/include/linux/netpoll.h
===================================================================
@@ -26,6 +26,7 @@ struct netpoll {
 struct netpoll_info {
 	spinlock_t poll_lock;
 	int poll_owner;
+	int tries;
 	int rx_flags;
 	spinlock_t rx_lock;
 	struct netpoll *rx_np; /* netpoll that registered an rx_hook */

Index: l/net/core/netpoll.c
===================================================================
@@ -724,6 +724,10 @@ int netpoll_setup(struct netpoll *np)
 		npinfo->rx_np = np;
 		spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 	}
+
+	/* fill up the skb queue */
+	refill_skbs();
+
 	/* last thing to do is link it to the net device structure */
 	ndev->npinfo = npinfo;
 

Index: l/net/core/netpoll.c
===================================================================
@@ -731,6 +731,9 @@ int netpoll_setup(struct netpoll *np)
 	/* last thing to do is link it to the net device structure */
 	ndev->npinfo = npinfo;
 
+	/* avoid racing with NAPI reading npinfo */
+	synchronize_rcu();
+
 	return 0;
 
  release:

Index: l/include/linux/netpoll.h
===================================================================
@@ -9,6 +9,7 @@
 
 #include <linux/netdevice.h>
 #include <linux/interrupt.h>
+#include <linux/rcupdate.h>
 #include <linux/list.h>
 
 struct netpoll;

@@ -61,25 +62,31 @@ static inline int netpoll_rx(struct sk_b
 	return ret;
 }
 
-static inline void netpoll_poll_lock(struct net_device *dev)
+static inline void *netpoll_poll_lock(struct net_device *dev)
 {
+	rcu_read_lock(); /* deal with race on ->npinfo */
 	if (dev->npinfo) {
 		spin_lock(&dev->npinfo->poll_lock);
 		dev->npinfo->poll_owner = smp_processor_id();
+		return dev->npinfo;
 	}
+	return NULL;
 }
 
-static inline void netpoll_poll_unlock(struct net_device *dev)
+static inline void netpoll_poll_unlock(void *have)
 {
-	if (dev->npinfo) {
-		dev->npinfo->poll_owner = -1;
-		spin_unlock(&dev->npinfo->poll_lock);
+	struct netpoll_info *npi = have;
+
+	if (npi) {
+		npi->poll_owner = -1;
+		spin_unlock(&npi->poll_lock);
 	}
+	rcu_read_unlock();
 }
 
 #else
 #define netpoll_rx(a) 0
-#define netpoll_poll_lock(a)
+#define netpoll_poll_lock(a) 0
 #define netpoll_poll_unlock(a)
 #endif
 

Index: l/net/core/dev.c
===================================================================
@@ -1696,7 +1696,8 @@ static void net_rx_action(struct softirq
 	struct softnet_data *queue = &__get_cpu_var(softnet_data);
 	unsigned long start_time = jiffies;
 	int budget = netdev_budget;
-	
+	void *have;
+
 	local_irq_disable();
 
 	while (!list_empty(&queue->poll_list)) {

@@ -1709,10 +1710,10 @@ static void net_rx_action(struct softirq
 
 		dev = list_entry(queue->poll_list.next,
 				 struct net_device, poll_list);
-		netpoll_poll_lock(dev);
+		have = netpoll_poll_lock(dev);
 
 		if (dev->quota <= 0 || dev->poll(dev, &budget)) {
-			netpoll_poll_unlock(dev);
+			netpoll_poll_unlock(have);
 			local_irq_disable();
 			list_del(&dev->poll_list);
 			list_add_tail(&dev->poll_list, &queue->poll_list);

@@ -1721,7 +1722,7 @@ static void net_rx_action(struct softirq
 			else
 				dev->quota = dev->weight;
 		} else {
-			netpoll_poll_unlock(dev);
+			netpoll_poll_unlock(have);
 			dev_put(dev);
 			local_irq_disable();
 		}

Index: l/net/core/netpoll.c
===================================================================
@@ -356,7 +356,6 @@ static void arp_reply(struct sk_buff *sk
 	unsigned char *arp_ptr;
 	int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
 	u32 sip, tip;
-	unsigned long flags;
 	struct sk_buff *send_skb;
 	struct netpoll *np = NULL;