>> 	you can't use smaller offset than before to m_pulldown() - 2nd
>> 	arg needs to increase monotonically on each calls.  see m_pulldown
>> 	paper i've submitted to freenix couple of years ago.

	i wasn't clear enough.
	the restriction applies when you have pointers that pointing into
	data region of mbuf (you need to update all the pointers).
	if you don't have any pointer that pointing into the data region
	of mbuf, you are okay to call m_pulldown().

itojun