[PATCH BUGFIX 2/2] bfq-sq, bfq-mq: release oom-queue ref to root group on exit

[Paolo Valente]

On scheduler init, a reference to the root group, and a reference to
its corresponding blkg are taken for the oom queue. Yet these
references are not released on scheduler exit, which prevents these
objects from be freed. This commit adds the missing reference
releases.

Reported-by: Davide Ferrari <davideferrari8@xxxxxxxxx>
Signed-off-by: Paolo Valente <paolo.valente@xxxxxxxxxx>
---
 block/bfq-iosched.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index ea48b5c8f088..c56a495af2e8 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -5015,6 +5015,9 @@ static void bfq_exit_queue(struct elevator_queue *e)
 
 	hrtimer_cancel(&bfqd->idle_slice_timer);
 
+	/* release oom-queue reference to root group */
+	bfqg_and_blkg_put(bfqd->root_group);
+
 #ifdef CONFIG_BFQ_GROUP_IOSCHED
 	blkcg_deactivate_policy(bfqd->queue, &blkcg_policy_bfq);
 #else
-- 
2.15.1