cns3xxx: ethernet - revert: clean up tx descs only when needed

This reverts commit 0772ab938c0aedd7f4cc7127059d6ce8cf929dfa.

Trying to optimize calls to eth_complete_tx in this fasion causes a regression
where when sending only the tx queue can get disabled until a packet is
received. This original call to eth_schedule_poll() is scheduled so it
should not cause a performance issue.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>

SVN-Revision: 40592

target/linux/cns3xxx/files/drivers/net/ethernet/cavium/cns3xxx_eth.c

@@ -583,7 +583,7 @@ static void eth_check_num_used(struct _tx_ring *tx_ring)
 	}
 }
 
-static int eth_complete_tx(struct sw *sw)
+static void eth_complete_tx(struct sw *sw)
 {
 	struct _tx_ring *tx_ring = &sw->tx_ring;
 	struct tx_desc *desc;
@@ -615,8 +615,6 @@ static int eth_complete_tx(struct sw *sw)
 	tx_ring->free_index = index;
 	tx_ring->num_used -= i;
 	eth_check_num_used(tx_ring);
-
-	return TX_DESCS - tx_ring->num_used;
 }
 
 static int eth_poll(struct napi_struct *napi, int budget)
@@ -778,13 +776,11 @@ static int eth_xmit(struct sk_buff *skb, struct net_device *dev)
 	skb_walk_frags(skb, skb1)
 		nr_desc++;
 
+	eth_schedule_poll(sw);
 	spin_lock_bh(&tx_lock);
 	if ((tx_ring->num_used + nr_desc + 1) >= TX_DESCS) {
-		/* clean up tx descriptors when needed */
-		if (eth_complete_tx(sw) < nr_desc) {
-			spin_unlock_bh(&tx_lock);
-			return NETDEV_TX_BUSY;
-		}
+		spin_unlock_bh(&tx_lock);
+		return NETDEV_TX_BUSY;
 	}
 
 	index = index0 = tx_ring->cur_index;