1 files changed, 18 insertions, 14 deletions

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 9faafcd10e17..4a42ea2972ad 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1511,7 +1511,7 @@ int blkcg_activate_policy(struct gendisk *disk, const struct blkcg_policy *pol)
 retry:
 	spin_lock_irq(&q->queue_lock);
 
-	/* blkg_list is pushed at the head, reverse walk to allocate parents first */
+	/* blkg_list is pushed at the head, reverse walk to initialize parents first */
 	list_for_each_entry_reverse(blkg, &q->blkg_list, q_node) {
 		struct blkg_policy_data *pd;
 
@@ -1549,21 +1549,20 @@ retry:
 				goto enomem;
 		}
 
-		blkg->pd[pol->plid] = pd;
+		spin_lock(&blkg->blkcg->lock);
+
 		pd->blkg = blkg;
 		pd->plid = pol->plid;
-		pd->online = false;
-	}
+		blkg->pd[pol->plid] = pd;
 
-	/* all allocated, init in the same order */
-	if (pol->pd_init_fn)
-		list_for_each_entry_reverse(blkg, &q->blkg_list, q_node)
-			pol->pd_init_fn(blkg->pd[pol->plid]);
+		if (pol->pd_init_fn)
+			pol->pd_init_fn(pd);
 
-	list_for_each_entry_reverse(blkg, &q->blkg_list, q_node) {
 		if (pol->pd_online_fn)
-			pol->pd_online_fn(blkg->pd[pol->plid]);
-		blkg->pd[pol->plid]->online = true;
+			pol->pd_online_fn(pd);
+		pd->online = true;
+
+		spin_unlock(&blkg->blkcg->lock);
 	}
 
 	__set_bit(pol->plid, q->blkcg_pols);
@@ -1580,14 +1579,19 @@ out:
 	return ret;
 
 enomem:
-	/* alloc failed, nothing's initialized yet, free everything */
+	/* alloc failed, take down everything */
 	spin_lock_irq(&q->queue_lock);
 	list_for_each_entry(blkg, &q->blkg_list, q_node) {
 		struct blkcg *blkcg = blkg->blkcg;
+		struct blkg_policy_data *pd;
 
 		spin_lock(&blkcg->lock);
-		if (blkg->pd[pol->plid]) {
-			pol->pd_free_fn(blkg->pd[pol->plid]);
+		pd = blkg->pd[pol->plid];
+		if (pd) {
+			if (pd->online && pol->pd_offline_fn)
+				pol->pd_offline_fn(pd);
+			pd->online = false;
+			pol->pd_free_fn(pd);
 			blkg->pd[pol->plid] = NULL;
 		}
 		spin_unlock(&blkcg->lock);