From: Paolo Valente <paolo.valente@linaro.org>
Date: Tue, 9 Jan 2018 10:27:59 +0100
Subject: [PATCH] block, bfq: release oom-queue ref to root group on exit
Git-commit: 0d52af590552473666da5b6111e7182d6cd23f92
Patch-mainline: v4.16-rc1
References: bsc#1104967,FATE#325924
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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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@gmail.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 block/bfq-iosched.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 7bd789da7a29..7c0b7f60811c 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -4893,6 +4893,9 @@ 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
-- 
2.16.4