skge: NAPI/irq race fix

Fix a race in the receive NAPI, irq handling. The interrupt clear and the
start need to be separated.  Otherwise there is a window between the last
frame received and the NAPI done level handling.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>

diff --git a/drivers/net/skge.c b/drivers/net/skge.c
index 67fb19b..869c7cf 100644 (file)
--- a/drivers/net/skge.c
+++ b/drivers/net/skge.c
@@ -2678,8 +2678,7 @@ static int skge_poll(struct net_device *dev, int *budget)
 
        /* restart receiver */
        wmb();
-       skge_write8(hw, Q_ADDR(rxqaddr[skge->port], Q_CSR),
-                   CSR_START | CSR_IRQ_CL_F);
+       skge_write8(hw, Q_ADDR(rxqaddr[skge->port], Q_CSR), CSR_START);
 
        *budget -= work_done;
        dev->quota -= work_done;
@@ -2856,14 +2855,6 @@ static void skge_extirq(unsigned long data)
        local_irq_enable();
 }
 
-static inline void skge_wakeup(struct net_device *dev)
-{
-       struct skge_port *skge = netdev_priv(dev);
-
-       prefetch(skge->rx_ring.to_clean);
-       netif_rx_schedule(dev);
-}
-
 static irqreturn_t skge_intr(int irq, void *dev_id, struct pt_regs *regs)
 {
        struct skge_hw *hw = dev_id;
@@ -2874,13 +2865,15 @@ static irqreturn_t skge_intr(int irq, void *dev_id, struct pt_regs *regs)
 
        status &= hw->intr_mask;
        if (status & IS_R1_F) {
+               skge_write8(hw, Q_ADDR(Q_R1, Q_CSR), CSR_IRQ_CL_F);
                hw->intr_mask &= ~IS_R1_F;
-               skge_wakeup(hw->dev[0]);
+               netif_rx_schedule(hw->dev[0]);
        }
 
        if (status & IS_R2_F) {
+               skge_write8(hw, Q_ADDR(Q_R2, Q_CSR), CSR_IRQ_CL_F);
                hw->intr_mask &= ~IS_R2_F;
-               skge_wakeup(hw->dev[1]);
+               netif_rx_schedule(hw->dev[1]);
        }
 
        if (status & IS_XA1_F)