e1000: do not modify tx_queue_len on link speed change

Previously the driver tweaked txqueuelen to avoid false Tx hang reports
seen at half duplex.  This had the effect of overriding user set values
on link change/reset. Testing shows that adjusting only the timeout
factor is sufficient to prevent Tx hang reports at half duplex.

This patch removes all instances of tx_queue_len in the driver.

Based on e1000e patch by Franco Fichtner <franco@lastsummer.de>

CC: Franco Fichtner <franco@lastsummer.de>
Signed-off-by: NEmil Tantilov <emil.s.tantilov@intel.com>
Acked-by: NJesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/e1000/e1000.h

@@ -261,7 +261,6 @@ struct e1000_adapter {
 	/* TX */
 	struct e1000_tx_ring *tx_ring;      /* One per active queue */
 	unsigned int restart_queue;
-	unsigned long tx_queue_len;
 	u32 txd_cmd;
 	u32 tx_int_delay;
 	u32 tx_abs_int_delay;

drivers/net/e1000/e1000_main.c

@@ -383,8 +383,6 @@ static void e1000_configure(struct e1000_adapter *adapter)
 		adapter->alloc_rx_buf(adapter, ring,
 		                      E1000_DESC_UNUSED(ring));
 	}
-
-	adapter->tx_queue_len = netdev->tx_queue_len;
 }
 
 int e1000_up(struct e1000_adapter *adapter)
@@ -503,7 +501,6 @@ void e1000_down(struct e1000_adapter *adapter)
 	del_timer_sync(&adapter->watchdog_timer);
 	del_timer_sync(&adapter->phy_info_timer);
 
-	netdev->tx_queue_len = adapter->tx_queue_len;
 	adapter->link_speed = 0;
 	adapter->link_duplex = 0;
 	netif_carrier_off(netdev);
@@ -2316,19 +2313,15 @@ static void e1000_watchdog(unsigned long data)
 			        E1000_CTRL_RFCE) ? "RX" : ((ctrl &
 			        E1000_CTRL_TFCE) ? "TX" : "None" )));
 
-			/* tweak tx_queue_len according to speed/duplex
-			 * and adjust the timeout factor */
-			netdev->tx_queue_len = adapter->tx_queue_len;
+			/* adjust timeout factor according to speed/duplex */
 			adapter->tx_timeout_factor = 1;
 			switch (adapter->link_speed) {
 			case SPEED_10:
 				txb2b = false;
-				netdev->tx_queue_len = 10;
 				adapter->tx_timeout_factor = 16;
 				break;
 			case SPEED_100:
 				txb2b = false;
-				netdev->tx_queue_len = 100;
 				/* maybe add some timeout factor ? */
 				break;
 			}