-/**
- * blkg_stat_recursive_sum - collect hierarchical blkg_stat
- * @blkg: blkg of interest
- * @pol: blkcg_policy which contains the blkg_stat
- * @off: offset to the blkg_stat in blkg_policy_data or @blkg
- *
- * Collect the blkg_stat specified by @blkg, @pol and @off and all its
- * online descendants and their aux counts. The caller must be holding the
- * queue lock for online tests.
- *
- * If @pol is NULL, blkg_stat is at @off bytes into @blkg; otherwise, it is
- * at @off bytes into @blkg's blkg_policy_data of the policy.
- */
-u64 blkg_stat_recursive_sum(struct blkcg_gq *blkg,
- struct blkcg_policy *pol, int off)
-{
- struct blkcg_gq *pos_blkg;
- struct cgroup_subsys_state *pos_css;
- u64 sum = 0;
-
- lockdep_assert_held(&blkg->q->queue_lock);
-
- rcu_read_lock();
- blkg_for_each_descendant_pre(pos_blkg, pos_css, blkg) {
- struct blkg_stat *stat;
-
- if (!pos_blkg->online)
- continue;
-
- if (pol)
- stat = (void *)blkg_to_pd(pos_blkg, pol) + off;
- else
- stat = (void *)blkg + off;
-
- sum += blkg_stat_read(stat) + atomic64_read(&stat->aux_cnt);
- }
- rcu_read_unlock();
-
- return sum;
-}
-EXPORT_SYMBOL_GPL(blkg_stat_recursive_sum);
-