From: Stephen Hemminger <shemminger@osdl.org>
Date: Wed, 22 Feb 2006 18:28:33 +0000 (-0800)
Subject: skge: NAPI/irq race fix
X-Git-Tag: v2.6.16-rc5~53^2~1^2~2
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a9cdab869ec343ccc601484fb535813e16c25f70;p=linux-2.6

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 67fb19b8fd..869c7cfb99 100644
--- 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)