kernel: clist code question

[utzoo!decvax!cca!Dave-Yost at RAND-UNIX]

Sender: day at RAND-UNIX
For kernel hackers:

Is there any good reason why the
clist code needs to be so cautious
when it checks to see if a clist is
empty?  I.e. why it checks for c_cl == NULL
and for c_cc < 0 both?  Is this just something
that should be cleaned up, or is there a magic
trick that I need to watch out for?

--dave