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[v2,2/3] block, bfq: avoid moving bfqq to it's parent bfqg

Message ID 20211231032354.793092-3-yukuai3@huawei.com (mailing list archive)
State New, archived
Headers show
Series block, bfq: minor cleanup and fix | expand

Commit Message

Yu Kuai Dec. 31, 2021, 3:23 a.m. UTC 
Moving bfqq to it's parent bfqg is pointless.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 block/bfq-cgroup.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)
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Patch

diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c
index 09ff0bb1042c..5e65b0407e85 100644
--- a/block/bfq-cgroup.c
+++ b/block/bfq-cgroup.c
@@ -645,6 +645,14 @@  void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq,
 		   struct bfq_group *bfqg)
 {
 	struct bfq_entity *entity = &bfqq->entity;
+	struct bfq_group *old_parent = bfq_group(bfqq);
+
+	/*
+	 * No point to move bfqq to the same group, which can happen when
+	 * root group is offlined
+	 */
+	if (old_parent == bfqg)
+		return;
 
 	/*
 	 * Get extra reference to prevent bfqq from being freed in
@@ -666,7 +674,7 @@  void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq,
 		bfq_deactivate_bfqq(bfqd, bfqq, false, false);
 	else if (entity->on_st_or_in_serv)
 		bfq_put_idle_entity(bfq_entity_service_tree(entity), entity);
-	bfqg_and_blkg_put(bfqq_group(bfqq));
+	bfqg_and_blkg_put(old_parent);
 
 	if (entity->parent &&
 	    entity->parent->last_bfqq_created == bfqq)