[NET]: Fix TX timeout regression in Intel drivers.

This fixes a regression added by changeset
53e52c72 ("[NET]: Make ->poll()
breakout consistent in Intel ethernet drivers.")

As pointed out by Jesse Brandeburg, for three of the drivers edited
above there is breakout logic in the *_clean_tx_irq() code to prevent
running TX reclaim forever.  If this occurs, we have to elide NAPI
poll completion or else those TX events will never be serviced.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NJesse Brandeburg <jesse.brandeburg@intel.com>

drivers/net/e1000/e1000_main.c

@@ -3919,7 +3919,7 @@ e1000_clean(struct napi_struct *napi, int budget)
 {
 	struct e1000_adapter *adapter = container_of(napi, struct e1000_adapter, napi);
 	struct net_device *poll_dev = adapter->netdev;
-	int work_done = 0;
+	int tx_cleaned = 0, work_done = 0;
 
 	/* Must NOT use netdev_priv macro here. */
 	adapter = poll_dev->priv;
@@ -3929,14 +3929,17 @@ e1000_clean(struct napi_struct *napi, int budget)
 	 * simultaneously.  A failure obtaining the lock means
 	 * tx_ring[0] is currently being cleaned anyway. */
 	if (spin_trylock(&adapter->tx_queue_lock)) {
-		e1000_clean_tx_irq(adapter,
-				   &adapter->tx_ring[0]);
+		tx_cleaned = e1000_clean_tx_irq(adapter,
+						&adapter->tx_ring[0]);
 		spin_unlock(&adapter->tx_queue_lock);
 	}
 
 	adapter->clean_rx(adapter, &adapter->rx_ring[0],
 	                  &work_done, budget);
 
+	if (tx_cleaned)
+		work_done = budget;
+
 	/* If budget not fully consumed, exit the polling mode */
 	if (work_done < budget) {
 		if (likely(adapter->itr_setting & 3))

drivers/net/e1000e/netdev.c

@@ -1384,7 +1384,7 @@ static int e1000_clean(struct napi_struct *napi, int budget)
 {
 	struct e1000_adapter *adapter = container_of(napi, struct e1000_adapter, napi);
 	struct net_device *poll_dev = adapter->netdev;
-	int work_done = 0;
+	int tx_cleaned = 0, work_done = 0;
 
 	/* Must NOT use netdev_priv macro here. */
 	adapter = poll_dev->priv;
@@ -1394,12 +1394,15 @@ static int e1000_clean(struct napi_struct *napi, int budget)
 	 * simultaneously.  A failure obtaining the lock means
 	 * tx_ring is currently being cleaned anyway. */
 	if (spin_trylock(&adapter->tx_queue_lock)) {
-		e1000_clean_tx_irq(adapter);
+		tx_cleaned = e1000_clean_tx_irq(adapter);
 		spin_unlock(&adapter->tx_queue_lock);
 	}
 
 	adapter->clean_rx(adapter, &work_done, budget);
 
+	if (tx_cleaned)
+		work_done = budget;
+
 	/* If budget not fully consumed, exit the polling mode */
 	if (work_done < budget) {
 		if (adapter->itr_setting & 3)

drivers/net/ixgbe/ixgbe_main.c

@@ -1468,13 +1468,16 @@ static int ixgbe_clean(struct napi_struct *napi, int budget)
 	struct ixgbe_adapter *adapter = container_of(napi,
 					struct ixgbe_adapter, napi);
 	struct net_device *netdev = adapter->netdev;
-	int work_done = 0;
+	int tx_cleaned = 0, work_done = 0;
 
 	/* In non-MSIX case, there is no multi-Tx/Rx queue */
-	ixgbe_clean_tx_irq(adapter, adapter->tx_ring);
+	tx_cleaned = ixgbe_clean_tx_irq(adapter, adapter->tx_ring);
 	ixgbe_clean_rx_irq(adapter, &adapter->rx_ring[0], &work_done,
 			   budget);
 
+	if (tx_cleaned)
+		work_done = budget;
+
 	/* If budget not fully consumed, exit the polling mode */
 	if (work_done < budget) {
 		netif_rx_complete(netdev, napi);