+ /*
+ * Since the memtype_rbroot tree allows overlapping ranges,
+ * rbt_memtype_erase() checks with EXACT_MATCH first, i.e. free
+ * a whole node for the munmap case. If no such entry is found,
+ * it then checks with END_MATCH, i.e. shrink the size of a node
+ * from the end for the mremap case.
+ */
+ data = memtype_rb_match(&memtype_rbroot, start, end,
+ MEMTYPE_EXACT_MATCH);
+ if (!data) {
+ data = memtype_rb_match(&memtype_rbroot, start, end,
+ MEMTYPE_END_MATCH);
+ if (!data)
+ return ERR_PTR(-EINVAL);
+ }
+
+ if (data->start == start) {
+ /* munmap: erase this node */
+ rb_erase_augmented(&data->rb, &memtype_rbroot,
+ &memtype_rb_augment_cb);
+ } else {
+ /* mremap: update the end value of this node */
+ rb_erase_augmented(&data->rb, &memtype_rbroot,
+ &memtype_rb_augment_cb);
+ data->end = start;
+ data->subtree_max_end = data->end;
+ memtype_rb_insert(&memtype_rbroot, data);
+ return NULL;
+ }