natsemi: netpoll fixes

Fix two issues in this driver's netpoll path: one usual, with spin_unlock_irq()
enabling interrupts which nobody asks it to do (that has been fixed recently in
a number of drivers) and one unusual, with poll_controller() method possibly
causing loss of interrupts due to the interrupt status register being cleared
by a simple read and the interrpupt handler simply storing it, not accumulating.

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 19 insertions, 5 deletions

diff --git a/drivers/net/natsemi.c b/drivers/net/natsemi.c
index 5c57433cb306..c6172a77a6d7 100644
--- a/drivers/net/natsemi.c
+++ b/drivers/net/natsemi.c
@@ -2024,6 +2024,7 @@ static int start_tx(struct sk_buff *skb, struct net_device *dev)
         struct netdev_private *np = netdev_priv(dev);
         void __iomem * ioaddr = ns_ioaddr(dev);
         unsigned entry;
+        unsigned long flags;
 
         /* Note: Ordering is important here, set the field with the
            "ownership" bit last, and only then increment cur_tx. */
@@ -2037,7 +2038,7 @@ static int start_tx(struct sk_buff *skb, struct net_device *dev)
 
         np->tx_ring[entry].addr = cpu_to_le32(np->tx_dma[entry]);
 
-        spin_lock_irq(&np->lock);
+        spin_lock_irqsave(&np->lock, flags);
 
         if (!np->hands_off) {
                 np->tx_ring[entry].cmd_status = cpu_to_le32(DescOwn | skb->len);
@@ -2056,7 +2057,7 @@ static int start_tx(struct sk_buff *skb, struct net_device *dev)
                 dev_kfree_skb_irq(skb);
                 np->stats.tx_dropped++;
         }
-        spin_unlock_irq(&np->lock);
+        spin_unlock_irqrestore(&np->lock, flags);
 
         dev->trans_start = jiffies;
 
@@ -2222,6 +2223,8 @@ static void netdev_rx(struct net_device *dev, int *work_done, int work_to_do)
                 pkt_len = (desc_status & DescSizeMask) - 4;
                 if ((desc_status&(DescMore|DescPktOK|DescRxLong)) != DescPktOK){
                         if (desc_status & DescMore) {
+                                unsigned long flags;
+
                                 if (netif_msg_rx_err(np))
                                         printk(KERN_WARNING
                                                 "%s: Oversized(?) Ethernet "
@@ -2236,12 +2239,12 @@ static void netdev_rx(struct net_device *dev, int *work_done, int work_to_do)
                                  * reset procedure documented in
                                  * AN-1287. */
 
-                                spin_lock_irq(&np->lock);
+                                spin_lock_irqsave(&np->lock, flags);
                                 reset_rx(dev);
                                 reinit_rx(dev);
                                 writel(np->ring_dma, ioaddr + RxRingPtr);
                                 check_link(dev);
-                                spin_unlock_irq(&np->lock);
+                                spin_unlock_irqrestore(&np->lock, flags);
 
                                 /* We'll enable RX on exit from this
                                  * function. */
@@ -2396,8 +2399,19 @@ static struct net_device_stats *get_stats(struct net_device *dev)
 #ifdef CONFIG_NET_POLL_CONTROLLER
 static void natsemi_poll_controller(struct net_device *dev)
 {
+        struct netdev_private *np = netdev_priv(dev);
+
         disable_irq(dev->irq);
-        intr_handler(dev->irq, dev);
+
+        /*
+         * A real interrupt might have already reached us at this point
+         * but NAPI might still haven't called us back.  As the interrupt
+         * status register is cleared by reading, we should prevent an
+         * interrupt loss in this case...
+         */
+        if (!np->intr_status)
+                intr_handler(dev->irq, dev);
+
         enable_irq(dev->irq);
 }
 #endif