[PATCH] spinlock consolidation

[pandora-kernel.git] / net / core / netpoll.c

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index c327c9e..5265dfd 100644 (file)
--- a/net/core/netpoll.c
+++ b/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;
@@ -248,14 +249,14 @@ static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
        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)
@@ -265,30 +266,37 @@ repeat:
                return;
        }
 
-       spin_lock(&np->dev->xmit_lock);
-       np->dev->xmit_lock_owner = smp_processor_id();
+       do {
+               npinfo->tries--;
+               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)) {
+               /*
+                * 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);
+                       udelay(50);
+                       continue;
+               }
+
+               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) {
+                       npinfo->tries = MAX_RETRIES; /* reset */
+                       return;
+               }
 
-       /* transmit busy */
-       if(status) {
+               /* transmit busy */
                netpoll_poll(np);
-               goto repeat;
-       }
+               udelay(50);
+       } while (npinfo->tries > 0);
 }
 
 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
@@ -349,15 +357,11 @@ static void arp_reply(struct sk_buff *skb)
        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;
 
-       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;
 
@@ -639,10 +643,12 @@ int netpoll_setup(struct netpoll *np)
                if (!npinfo)
                        goto release;
 
+               npinfo->rx_flags = 0;
                npinfo->rx_np = NULL;
-               npinfo->poll_lock = SPIN_LOCK_UNLOCKED;
+               spin_lock_init(&npinfo->poll_lock);
                npinfo->poll_owner = -1;
-               npinfo->rx_lock = SPIN_LOCK_UNLOCKED;
+               npinfo->tries = MAX_RETRIES;
+               spin_lock_init(&npinfo->rx_lock);
        } else
                npinfo = ndev->npinfo;
 
@@ -718,9 +724,16 @@ 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;
 
+       /* avoid racing with NAPI reading npinfo */
+       synchronize_rcu();
+
        return 0;
 
  release: