[PATCH] skge: irq lock race

The driver needs to access the IRQ status inside of lock to avoid
races with other places changing IRQ mask etc. This may be related
to some of the SMP bugs reported against skge in kernel bugzilla.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/net/skge.c b/drivers/net/skge.c
index e86a88a..8a321be 100644 (file)
--- a/drivers/net/skge.c
+++ b/drivers/net/skge.c
@@ -2891,13 +2891,15 @@ static irqreturn_t skge_intr(int irq, void *dev_id, struct pt_regs *regs)
 {
        struct skge_hw *hw = dev_id;
        u32 status;
+       int handled = 0;
 
+       spin_lock(&hw->hw_lock);
        /* Reading this register masks IRQ */
        status = skge_read32(hw, B0_SP_ISRC);
        if (status == 0)
-               return IRQ_NONE;
+               goto out;
 
-       spin_lock(&hw->hw_lock);
+       handled = 1;
        status &= hw->intr_mask;
        if (status & IS_EXT_REG) {
                hw->intr_mask &= ~IS_EXT_REG;
@@ -2959,9 +2961,10 @@ static irqreturn_t skge_intr(int irq, void *dev_id, struct pt_regs *regs)
 
        skge_write32(hw, B0_IMSK, hw->intr_mask);
        skge_read32(hw, B0_IMSK);
+out:
        spin_unlock(&hw->hw_lock);
 
-       return IRQ_HANDLED;
+       return IRQ_RETVAL(handled);
 }
 
 #ifdef CONFIG_NET_POLL_CONTROLLER