e1000e: fix close interrupt race

As noticed by Alan Cox, it is possible for e1000e to exit its interrupt
handler or NAPI with interrupts enabled even when the driver is unloading or
being configured administratively down.

fix related to fix for: http://bugzilla.kernel.org/show_bug.cgi?id=12876

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
CC: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/e1000e/netdev.c

@@ -1261,7 +1261,8 @@ static irqreturn_t e1000_msix_other(int irq, void *data)
 	u32 icr = er32(ICR);
 
 	if (!(icr & E1000_ICR_INT_ASSERTED)) {
-		ew32(IMS, E1000_IMS_OTHER);
+		if (!test_bit(__E1000_DOWN, &adapter->state))
+			ew32(IMS, E1000_IMS_OTHER);
 		return IRQ_NONE;
 	}
 
@@ -1278,7 +1279,8 @@ static irqreturn_t e1000_msix_other(int irq, void *data)
 	}
 
 no_link_interrupt:
-	ew32(IMS, E1000_IMS_LSC | E1000_IMS_OTHER);
+	if (!test_bit(__E1000_DOWN, &adapter->state))
+		ew32(IMS, E1000_IMS_LSC | E1000_IMS_OTHER);
 
 	return IRQ_HANDLED;
 }
@@ -2015,10 +2017,12 @@ static int e1000_clean(struct napi_struct *napi, int budget)
 		if (adapter->itr_setting & 3)
 			e1000_set_itr(adapter);
 		napi_complete(napi);
-		if (adapter->msix_entries)
-			ew32(IMS, adapter->rx_ring->ims_val);
-		else
-			e1000_irq_enable(adapter);
+		if (!test_bit(__E1000_DOWN, &adapter->state)) {
+			if (adapter->msix_entries)
+				ew32(IMS, adapter->rx_ring->ims_val);
+			else
+				e1000_irq_enable(adapter);
+		}
 	}
 
 	return work_done;