net: fix network driver ndo_start_xmit() return values (part 1)

Fix up drivers that return an errno value to qdisc_restart(), causing
qdisc_restart() to print a warning and requeue/retransmit the skb.

- xpnet: memory allocation error, intention is to drop
- ethoc: oversized packet, packet must be dropped
- ibmlana: skb freed: use after free
- rrunner: skb freed: use after free
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/misc/sgi-xp/xpnet.c

@@ -450,7 +450,8 @@ xpnet_dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
 			 "packet\n", sizeof(struct xpnet_pending_msg));
 
 		dev->stats.tx_errors++;
-		return -ENOMEM;
+		dev_kfree_skb(skb);
+		return NETDEV_TX_OK;
 	}
 
 	/* get the beginning of the first cacheline and end of last */

drivers/net/ethoc.c

@@ -811,7 +811,7 @@ static int ethoc_start_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	if (unlikely(skb->len > ETHOC_BUFSIZ)) {
 		priv->stats.tx_errors++;
-		return -EMSGSIZE;
+		goto out;
 	}
 
 	entry = priv->cur_tx % priv->num_tx;
@@ -840,9 +840,9 @@ static int ethoc_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	}
 
 	dev->trans_start = jiffies;
-	dev_kfree_skb(skb);
-
 	spin_unlock_irq(&priv->lock);
+out:
+	dev_kfree_skb(skb);
 	return NETDEV_TX_OK;
 }
 

drivers/net/ibmlana.c

@@ -815,7 +815,7 @@ static int ibmlana_close(struct net_device *dev)
 static int ibmlana_tx(struct sk_buff *skb, struct net_device *dev)
 {
 	ibmlana_priv *priv = netdev_priv(dev);
-	int retval = 0, tmplen, addr;
+	int tmplen, addr;
 	unsigned long flags;
 	tda_t tda;
 	int baddr;
@@ -824,7 +824,6 @@ static int ibmlana_tx(struct sk_buff *skb, struct net_device *dev)
 	   the upper layer is in deep desperation and we simply ignore the frame. */
 
 	if (priv->txusedcnt >= TXBUFCNT) {
-		retval = -EIO;
 		dev->stats.tx_dropped++;
 		goto tx_done;
 	}
@@ -874,7 +873,7 @@ static int ibmlana_tx(struct sk_buff *skb, struct net_device *dev)
 	spin_unlock_irqrestore(&priv->lock, flags);
 tx_done:
 	dev_kfree_skb(skb);
-	return retval;
+	return NETDEV_TX_OK;
 }
 
 /* switch receiver mode. */

drivers/net/rrunner.c

@@ -1425,7 +1425,7 @@ static int rr_start_xmit(struct sk_buff *skb, struct net_device *dev)
 		if (!(new_skb = dev_alloc_skb(len + 8))) {
 			dev_kfree_skb(skb);
 			netif_wake_queue(dev);
-			return -EBUSY;
+			return NETDEV_TX_OK;
 		}
 		skb_reserve(new_skb, 8);
 		skb_put(new_skb, len);