Re: [PATCH RFC] struct list_node

From: Linus Torvalds
Date: Sun Jun 10 2007 - 13:20:46 EST

On Sun, 10 Jun 2007, Rusty Russell wrote:
> The current list.h has the same type for list elements and list heads
> even though most code and coders treat them as distinct.

I think the old list.h is technically superior to yours.

Exactly *because* nodes and heads are interchangeable.

In fact, you are incorrect that "most code" treat them as distinct. Most
code that uses list.h in fact uses it as a list of entries, often without
any head at all (and each *entry* is a point of removal), because the way
to actually *find* the structure that contains the lists is separate from
the lists themselves.

In other words, I think your patch is HORRIBLY BAD, because it totally
obscures the beauty of the current list.h implementation, and makes it be
something *average*.

The Linux kernel list.h is _better_ than most stupid list implementations
that think that a head node is different from the list node. Exactly
because it very naturally supports the notion of "this structure exists in
a 'ring of entries'" where each node is 100% equivalent to any other node,
and there _is_ no head.

And your patch totally misunderstands that, and breaks it.


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