i40e: Re-enable interrupt on ICR0

The hardware can occasionally give an interrupt on the misc
queue for which there is no driver work to do.  In that case
the driver was not re-enabling interrupts even though they
were auto masked by hardware.  This left interrupts disabled
on this queue.

Re-enable the interrupt whenever leaving this function.
Signed-off-by: Anjali Singhai Jain <anjali.singhai@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Kavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e_main.c

@@ -2758,16 +2758,16 @@ static irqreturn_t i40e_intr(int irq, void *data)
 {
 	struct i40e_pf *pf = (struct i40e_pf *)data;
 	struct i40e_hw *hw = &pf->hw;
+	irqreturn_t ret = IRQ_NONE;
 	u32 icr0, icr0_remaining;
 	u32 val, ena_mask;
 
 	icr0 = rd32(hw, I40E_PFINT_ICR0);
+	ena_mask = rd32(hw, I40E_PFINT_ICR0_ENA);
 
 	/* if sharing a legacy IRQ, we might get called w/o an intr pending */
 	if ((icr0 & I40E_PFINT_ICR0_INTEVENT_MASK) == 0)
-		return IRQ_NONE;
-
-	ena_mask = rd32(hw, I40E_PFINT_ICR0_ENA);
+		goto enable_intr;
 
 	/* if interrupt but no bits showing, must be SWINT */
 	if (((icr0 & ~I40E_PFINT_ICR0_INTEVENT_MASK) == 0) ||
@@ -2843,7 +2843,9 @@ static irqreturn_t i40e_intr(int irq, void *data)
 		}
 		ena_mask &= ~icr0_remaining;
 	}
+	ret = IRQ_HANDLED;
 
+enable_intr:
 	/* re-enable interrupt causes */
 	wr32(hw, I40E_PFINT_ICR0_ENA, ena_mask);
 	if (!test_bit(__I40E_DOWN, &pf->state)) {
@@ -2851,7 +2853,7 @@ static irqreturn_t i40e_intr(int irq, void *data)
 		i40e_irq_dynamic_enable_icr0(pf);
 	}
 
-	return IRQ_HANDLED;
+	return ret;
 }
 
 /**