On Sun, 21 Nov 2010, Bruce Blinn wrote:
> > that also suggests that a passage on p. 91 of LKD3 is
> > inaccurate, where it claims that "because the lists are
> > circular, you can generally pass any element for head." but
> > that can't be right, since you must *always* keep track of
> > the head node for any list, to avoid processing it normally.
> > if you simply drop someone into the middle of a circular,
> > doubly-linked kernel list, there is no way that i can see to
> > know which node in that list is the head node when you run
> > across it during iteration.
> >
> > does this make sense?
>
> I think you are assuming that all lists have a separate list_head
> structure to locate the head of the list. I am not sure that is
> correct. For example, the task structures are linked toghether in a
> curcular list with no separate list_head structure. The
> init_task->tasks.next field is usually the starting point, but
> current->tasks.next should work just as well.
that may be true, but if it is, it's a *very* special case in that
it represents a list that *starts* with an initial entry (init_task),
so it can be processed differently. can you point out where a new
entry is added to that particular list?
rday
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Robert P. J. Day Waterloo, Ontario, CANADA
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