On Mon, Mar 18, 2013 at 4:21 PM, Davidlohr Bueso <davidlohr.bu...@hp.com> wrote:
> When checking the rbtree, account for more properties:
>
> - Both children of a red node are black.
> - The tree has at least 2**bh(v)-1 internal nodes.
> - WARN_ON_ONCE(is_red(rb) &&
> - (!rb_parent(rb) || is_red(rb_parent(rb))));
> +
> + if (is_red(rb)) {
> + /*
> + * root must be black and no path contains two
> + * consecutive red nodes.
> + */
> + WARN_ON_ONCE(!rb_parent(rb) || is_red(rb_parent(rb)));
> +
> + /* both children of a red node are black */
> + WARN_ON_ONCE(is_red(rb->rb_left) ||
> is_red(rb->rb_right));
> + }
This seems quite redundant with the previous test - if we're going to
visit each children, then at that point we're going to check that they
can't be black if their parent (the current node) is black. So I don't
see that the tests adds any coverage.
> WARN_ON_ONCE(count != nr_nodes);
> + WARN_ON_ONCE(count < (1 << black_path_count(rb_last(&root))) - 1);
I like this last check - it can also be seen as a consequence of the
others, but it it's only one line and it nicely sums up what the other
properties are for :)
--
Michel "Walken" Lespinasse
A program is never fully debugged until the last user dies.
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