[PATCH] block: put the reference of the io scheduler module after switching back

From: Jinlong Chen
Date: Tue Oct 11 2022 - 06:22:16 EST


We got a reference of the io scheduler module in
blk_mq_elv_switch_none to prevent the module from
being removed. We need to put that reference back
once we are done.

Signed-off-by: Jinlong Chen <chenjinlong2016@xxxxxxxxxxx>
---
block/blk-mq.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 8070b6c10e8d..8dfe3bf3e599 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -4595,6 +4595,13 @@ static void blk_mq_elv_switch_back(struct list_head *head,

mutex_lock(&q->sysfs_lock);
elevator_switch(q, t);
+ /**
+ * We got a reference of the io scheduler module in
+ * blk_mq_elv_switch_none to prevent the module from
+ * being removed. We need to put that reference back
+ * once we are done.
+ */
+ module_put(t->elevator_owner);
mutex_unlock(&q->sysfs_lock);
}

--
2.34.1