On Thu, Nov 03, 2022 at 05:31:17AM +0000, Tian, Kevin wrote:
> > From: Jason Gunthorpe <jgg@xxxxxxxxxx>
> > Sent: Wednesday, October 26, 2022 2:12 AM
> > +/*
> > + * This iterator travels over spans in an interval tree. It does not return
> > + * nodes but classifies each span as either a hole, where no nodes intersect,
> > or
> > + * a used, which is fully covered by nodes. Each iteration step toggles
> > between
> > + * hole and used until the entire range is covered. The returned spans
> > always
> > + * fully cover the requested range.
> > + *
> > + * The iterator is greedy, it always returns the largest hole or used possible,
> > + * consolidating all consecutive nodes.
> > + *
> > + * Only is_hole, start_hole/used and last_hole/used are part of the external
> > + * interface.
>
> slightly better readability if moving this sentence into the structure as
> the break line
Do you mean like this?
@@ -37,13 +37,16 @@ interval_tree_iter_next(struct interval_tree_node *node,
* The iterator is greedy, it always returns the largest hole or used possible,
* consolidating all consecutive nodes.
- *
- * Only is_hole, start_hole/used and last_hole/used are part of the external
- * interface.
*/
struct interval_tree_span_iter {
struct interval_tree_node *nodes[2];
unsigned long first_index;
unsigned long last_index;
+
+ /*
+ * Only is_hole, start_hole/used and last_hole/used are part of the
+ * external interface.
+ */
union {
unsigned long start_hole;
unsigned long start_used;
> > +void interval_tree_span_iter_advance(struct interval_tree_span_iter *iter,
> > + struct rb_root_cached *itree,
> > + unsigned long new_index)
> > +{
> > + if (iter->is_hole == -1)
> > + return;
> > +
> > + iter->first_index = new_index;
> > + if (new_index == iter->last_index) {
> > + iter->is_hole = -1;
> > + return;
> > + }
> > +
> > + /* Rely on the union aliasing hole/used */
> > + if (iter->start_hole <= new_index && new_index <= iter->last_hole) {
>
> "<=" to "<"
>
> > + iter->start_hole = new_index;
> > + return;
> > + }
Hrm, I don't think so.. This is testing if new_index is valid for the
current span. new_index == start_XXX is a valid index of the span and
new_index == last_XX is also a valid index, so either of them should
just update start_XX and do nothing else.
Thanks,
Jason
