>>It would appear that the behaviour of m_copy()/m_copym() is changed,
>>depending on whether or not M_EXT is set.  If M_EXT is set, then the
>	I believe the above is the normal behavior, and this has been there
>	for a very long time.  See TCP/IP Illustrated volume 2, section 2.9.
>	To handle, for example, IPsec ESP header (which requires total
>	modification of the packet), we reimplement mbuf chain copying,
>	without cluster sharing, in few places.

	In fact, there are only very few places we would need a deep copy.
	IPsec ESP handler processing is the only one item I can imagine.
	(do any of drivers need a deep copy?  I believe not)

itojun