Partial revert "e1000e: Avoid receiver overrun interrupt bursts"

This partially reverts commit 4aea7a5c5e940c1723add439f4088844cd26196d.

We keep the fix for the first part of the problem (1) described in the log
of that commit, that is to read ICR in the other interrupt handler. We
remove the fix for the second part of the problem (2), Other interrupt
throttling.

Bursts of "Other" interrupts may once again occur during rxo (receive
overflow) traffic conditions. This is deemed acceptable in the interest of
avoiding unforeseen fallout from changes that are not strictly necessary.
As discussed, the e1000e driver should be in "maintenance mode".

Link: https://www.spinics.net/lists/netdev/msg480675.html
Signed-off-by: Benjamin Poirier <bpoirier@suse.com>
Acked-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/e1000e/netdev.c

@@ -1915,21 +1915,10 @@ static irqreturn_t e1000_msix_other(int __always_unused irq, void *data)
 	struct e1000_adapter *adapter = netdev_priv(netdev);
 	struct e1000_hw *hw = &adapter->hw;
 	u32 icr;
-	bool enable = true;
 
 	icr = er32(ICR);
 	ew32(ICR, E1000_ICR_OTHER);
 
-	if (icr & E1000_ICR_RXO) {
-		ew32(ICR, E1000_ICR_RXO);
-		enable = false;
-		/* napi poll will re-enable Other, make sure it runs */
-		if (napi_schedule_prep(&adapter->napi)) {
-			adapter->total_rx_bytes = 0;
-			adapter->total_rx_packets = 0;
-			__napi_schedule(&adapter->napi);
-		}
-	}
 	if (icr & E1000_ICR_LSC) {
 		ew32(ICR, E1000_ICR_LSC);
 		hw->mac.get_link_status = true;
@@ -1938,7 +1927,7 @@ static irqreturn_t e1000_msix_other(int __always_unused irq, void *data)
 			mod_timer(&adapter->watchdog_timer, jiffies + 1);
 	}
 
-	if (enable && !test_bit(__E1000_DOWN, &adapter->state))
+	if (!test_bit(__E1000_DOWN, &adapter->state))
 		ew32(IMS, E1000_IMS_OTHER);
 
 	return IRQ_HANDLED;
@@ -2708,8 +2697,7 @@ static int e1000e_poll(struct napi_struct *napi, int weight)
 		napi_complete_done(napi, work_done);
 		if (!test_bit(__E1000_DOWN, &adapter->state)) {
 			if (adapter->msix_entries)
-				ew32(IMS, adapter->rx_ring->ims_val |
-				     E1000_IMS_OTHER);
+				ew32(IMS, adapter->rx_ring->ims_val);
 			else
 				e1000_irq_enable(adapter);
 		}