unsigned int radix_tree_gang_lookup(const struct radix_tree_root *root, void **results, unsigned long first_index, unsigned int max_items);
unsigned int radix_tree_gang_lookup_tag(const struct radix_tree_root *root, void **results, unsigned long first_index, unsigned int max_items, unsigned int tag);
+/*
+ * On Linux, <linux/radix-tress.h> includes <linux/xarray.h>.
+ *
+ * However on FreeBSD, this is the opposite because an xarray is implemented on
+ * top of a radix-tree. Unfortunately, some code relies on the namespace
+ * pollution.
+ *
+ * Therefore we include <linux/xarray.h> here at the end because it depends on