skge: protect interrupt mask

There is a race between updating the irq mask and setting it
which can be triggered on SMP with a bad cable.
Similar patch from Ingo Molnar and Thomas Gleixner

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

2 files changed, 15 insertions, 7 deletions

diff --git a/drivers/net/skge.c b/drivers/net/skge.c
index af2e6782031b..25e028b7ce48 100644
--- a/drivers/net/skge.c
+++ b/drivers/net/skge.c
@@ -2185,8 +2185,10 @@ static int skge_up(struct net_device *dev)
         skge->tx_avail = skge->tx_ring.count - 1;
 
         /* Enable IRQ from port */
+        spin_lock_irq(&hw->hw_lock);
         hw->intr_mask |= portirqmask[port];
         skge_write32(hw, B0_IMSK, hw->intr_mask);
+        spin_unlock_irq(&hw->hw_lock);
 
         /* Initialize MAC */
         spin_lock_bh(&hw->phy_lock);
@@ -2244,8 +2246,10 @@ static int skge_down(struct net_device *dev)
         else
                 yukon_stop(skge);
 
+        spin_lock_irq(&hw->hw_lock);
         hw->intr_mask &= ~portirqmask[skge->port];
         skge_write32(hw, B0_IMSK, hw->intr_mask);
+        spin_unlock_irq(&hw->hw_lock);
 
         /* Stop transmitter */
         skge_write8(hw, Q_ADDR(txqaddr[port], Q_CSR), CSR_STOP);
@@ -2701,10 +2705,11 @@ static int skge_poll(struct net_device *dev, int *budget)
         if (work_done >=  to_do)
                 return 1; /* not done */
 
-        netif_rx_complete(dev);
-        hw->intr_mask |= portirqmask[skge->port];
-        skge_write32(hw, B0_IMSK, hw->intr_mask);
-        skge_read32(hw, B0_IMSK);
+        spin_lock_irq(&hw->hw_lock);
+        __netif_rx_complete(dev);
+        hw->intr_mask |= portirqmask[skge->port];
+        skge_write32(hw, B0_IMSK, hw->intr_mask);
+        spin_unlock_irq(&hw->hw_lock);
 
         return 0;
 }
@@ -2864,10 +2869,10 @@ static void skge_extirq(unsigned long data)
         }
         spin_unlock(&hw->phy_lock);
 
-        local_irq_disable();
+        spin_lock_irq(&hw->hw_lock);
         hw->intr_mask |= IS_EXT_REG;
         skge_write32(hw, B0_IMSK, hw->intr_mask);
-        local_irq_enable();
+        spin_unlock_irq(&hw->hw_lock);
 }
 
 static irqreturn_t skge_intr(int irq, void *dev_id, struct pt_regs *regs)
@@ -2878,7 +2883,7 @@ static irqreturn_t skge_intr(int irq, void *dev_id, struct pt_regs *regs)
         if (status == 0 || status == ~0) /* hotplug or shared irq */
                 return IRQ_NONE;
 
-        status &= hw->intr_mask;
+        spin_lock(&hw->hw_lock);
         if (status & IS_R1_F) {
                 skge_write8(hw, Q_ADDR(Q_R1, Q_CSR), CSR_IRQ_CL_F);
                 hw->intr_mask &= ~IS_R1_F;
@@ -2930,6 +2935,7 @@ static irqreturn_t skge_intr(int irq, void *dev_id, struct pt_regs *regs)
         }
 
         skge_write32(hw, B0_IMSK, hw->intr_mask);
+        spin_unlock(&hw->hw_lock);
 
         return IRQ_HANDLED;
 }
@@ -3298,6 +3304,7 @@ static int __devinit skge_probe(struct pci_dev *pdev,
 
         hw->pdev = pdev;
         spin_lock_init(&hw->phy_lock);
+        spin_lock_init(&hw->hw_lock);
         tasklet_init(&hw->ext_tasklet, skge_extirq, (unsigned long) hw);
 
         hw->regs = ioremap_nocache(pci_resource_start(pdev, 0), 0x4000);
diff --git a/drivers/net/skge.h b/drivers/net/skge.h
index 2efdacc290e5..941f12a333b6 100644
--- a/drivers/net/skge.h
+++ b/drivers/net/skge.h
@@ -2402,6 +2402,7 @@ struct skge_hw {
 
         struct tasklet_struct ext_tasklet;
         spinlock_t           phy_lock;
+        spinlock_t           hw_lock;
 };
 
 enum {