r8169: revert "add byte queue limit support".

This reverts commit 036dafa28da1e2565a8529de2ae663c37b7a0060.

First it appears in bisection, then reverting it solves the usual
netdev watchdog problem for different people. I don't have a proper
fix yet so get rid of it.

Bisected-and-reported-by: Alex Villacís Lasso <a_villacis@palosanto.com>
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/r8169.c

@@ -5656,7 +5656,6 @@ static void rtl8169_tx_clear(struct rtl8169_private *tp)
 {
 	rtl8169_tx_clear_range(tp, tp->dirty_tx, NUM_TX_DESC);
 	tp->cur_tx = tp->dirty_tx = 0;
-	netdev_reset_queue(tp->dev);
 }
 
 static void rtl_reset_work(struct rtl8169_private *tp)
@@ -5811,8 +5810,6 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb,
 
 	txd->opts2 = cpu_to_le32(opts[1]);
 
-	netdev_sent_queue(dev, skb->len);
-
 	skb_tx_timestamp(skb);
 
 	wmb();
@@ -5909,16 +5906,9 @@ static void rtl8169_pcierr_interrupt(struct net_device *dev)
 	rtl_schedule_task(tp, RTL_FLAG_TASK_RESET_PENDING);
 }
 
-struct rtl_txc {
-	int packets;
-	int bytes;
-};
-
 static void rtl_tx(struct net_device *dev, struct rtl8169_private *tp)
 {
-	struct rtl8169_stats *tx_stats = &tp->tx_stats;
 	unsigned int dirty_tx, tx_left;
-	struct rtl_txc txc = { 0, 0 };
 
 	dirty_tx = tp->dirty_tx;
 	smp_rmb();
@@ -5937,24 +5927,17 @@ static void rtl_tx(struct net_device *dev, struct rtl8169_private *tp)
 		rtl8169_unmap_tx_skb(&tp->pci_dev->dev, tx_skb,
 				     tp->TxDescArray + entry);
 		if (status & LastFrag) {
-			struct sk_buff *skb = tx_skb->skb;
-
-			txc.packets++;
-			txc.bytes += skb->len;
-			dev_kfree_skb(skb);
+			u64_stats_update_begin(&tp->tx_stats.syncp);
+			tp->tx_stats.packets++;
+			tp->tx_stats.bytes += tx_skb->skb->len;
+			u64_stats_update_end(&tp->tx_stats.syncp);
+			dev_kfree_skb(tx_skb->skb);
 			tx_skb->skb = NULL;
 		}
 		dirty_tx++;
 		tx_left--;
 	}
 
-	u64_stats_update_begin(&tx_stats->syncp);
-	tx_stats->packets += txc.packets;
-	tx_stats->bytes += txc.bytes;
-	u64_stats_update_end(&tx_stats->syncp);
-
-	netdev_completed_queue(dev, txc.packets, txc.bytes);
-
 	if (tp->dirty_tx != dirty_tx) {
 		tp->dirty_tx = dirty_tx;
 		/* Sync with rtl8169_start_xmit: