net: Allow skb_recycle_check to be done in stages

skb_recycle_check resets the skb if it's eligible for recycling.
However, there are times when a driver might want to optionally
manipulate the skb data with the skb before resetting the skb,
but after it has determined eligibility.  We do this by splitting the
eligibility check from the skb reset, creating two inline functions to
accomplish that task.

Change-Id: Ide33bfee796cd08db40b46ab7c0ed3a4a14bf2f8
Signed-off-by: Andy Fleming <afleming@freescale.com>
Acked-by: David Daney <david.daney@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net: constify skbuff and Qdisc elements

Preliminary patch before tcp constification

Change-Id: I02ff6ca5ce08bc0c2fce1c63cbc7dbd837b2e719
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>