e1000: Avoid unhandled IRQ

If hardware asserted an interrupt and driver is down,
then there is nothing to do so return IRQ_HANDLED
instead of IRQ_NONE. Returning IRQ_NONE in above
situation causes screaming IRQ on virtual machines.

CC: Andy Gospodarek <gospo@redhat.com>
Signed-off-by: Tushar Dave <tushar.n.dave@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
index 4ff88a6..e332aee 100644 (file)
--- a/drivers/net/e1000/e1000_main.c
+++ b/drivers/net/e1000/e1000_main.c
@@ -3478,9 +3478,17 @@ static irqreturn_t e1000_intr(int irq, void *data)
        struct e1000_hw *hw = &adapter->hw;
        u32 icr = er32(ICR);
 
-       if (unlikely((!icr) || test_bit(__E1000_DOWN, &adapter->flags)))
+       if (unlikely((!icr)))
                return IRQ_NONE;  /* Not our interrupt */
 
+       /*
+        * we might have caused the interrupt, but the above
+        * read cleared it, and just in case the driver is
+        * down there is nothing to do so return handled
+        */
+       if (unlikely(test_bit(__E1000_DOWN, &adapter->flags)))
+               return IRQ_HANDLED;
+
        if (unlikely(icr & (E1000_ICR_RXSEQ | E1000_ICR_LSC))) {
                hw->get_link_status = 1;
                /* guard against interrupt when we're going down */