net: Optimize hard_start_xmit() return checking

Recent changes in the TX error propagation require additional checking
and masking of values returned from hard_start_xmit(), mainly to
separate cases where skb was consumed. This aim can be simplified by
changing the order of NETDEV_TX and NET_XMIT codes, because the latter
are treated similarly to negative (ERRNO) values.

After this change much simpler dev_xmit_complete() is also used in
sch_direct_xmit(), so it is moved to netdevice.h.

Additionally NET_RX definitions in netdevice.h are moved up from
between TX codes to avoid confusion while reading the TX comment.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -1924,23 +1924,6 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
 	return rc;
 }
 
-static inline bool dev_xmit_complete(int rc)
-{
-	/* successful transmission */
-	if (rc == NETDEV_TX_OK)
-		return true;
-
-	/* error while transmitting, driver consumed skb */
-	if (rc < 0)
-		return true;
-
-	/* error while queueing to a different device, driver consumed skb */
-	if (rc & NET_XMIT_MASK)
-		return true;
-
-	return false;
-}
-
 /**
  *	dev_queue_xmit - transmit a buffer
  *	@skb: buffer to transmit