1 files changed, 5 insertions, 0 deletions

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index f5981e9d6ae2..8a8bb8796c6c 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -491,6 +491,7 @@ static void cgwb_release_workfn(struct work_struct *work)
 {
         struct bdi_writeback *wb = container_of(work, struct bdi_writeback,
                                                 release_work);
+        struct blkcg *blkcg = css_to_blkcg(wb->blkcg_css);
 
         mutex_lock(&wb->bdi->cgwb_release_mutex);
         wb_shutdown(wb);
@@ -499,6 +500,9 @@ static void cgwb_release_workfn(struct work_struct *work)
         css_put(wb->blkcg_css);
         mutex_unlock(&wb->bdi->cgwb_release_mutex);
 
+        /* triggers blkg destruction if cgwb_refcnt becomes zero */
+        blkcg_cgwb_put(blkcg);
+
         fprop_local_destroy_percpu(&wb->memcg_completions);
         percpu_ref_exit(&wb->refcnt);
         wb_exit(wb);
@@ -597,6 +601,7 @@ static int cgwb_create(struct backing_dev_info *bdi,
                         list_add_tail_rcu(&wb->bdi_node, &bdi->wb_list);
                         list_add(&wb->memcg_node, memcg_cgwb_list);
                         list_add(&wb->blkcg_node, blkcg_cgwb_list);
+                        blkcg_cgwb_get(blkcg);
                         css_get(memcg_css);
                         css_get(blkcg_css);
                 }