[PATCH V2 4/6] null_blk: move unregister_blkdev() after destroying dev in null_exit()

[Zizhi Wo]

In null_exit(), unregister_blkdev() was called before the null_blk
instances were destroyed, which is inconsistent with the cleanup order in
null_init(). Move it after null_destroy_dev() so that teardown happens in
the reverse order of initialization.

No functional change intended.

Suggested-by: Bart Van Assche <bvanassche@xxxxxxx>
Signed-off-by: Zizhi Wo <wozizhi@xxxxxxxxxxxxxxx>
---
 drivers/block/null_blk/main.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 024c89b36ddc..cab51301560e 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -2194,8 +2194,6 @@ static void __exit null_exit(void)
 
 	configfs_unregister_subsystem(&nullb_subsys);
 
-	unregister_blkdev(null_major, "nullb");
-
 	mutex_lock(&nullb_global_lock);
 	while (!list_empty(&nullb_list)) {
 		nullb = list_entry(nullb_list.next, struct nullb, list);
@@ -2203,6 +2201,8 @@ static void __exit null_exit(void)
 	}
 	mutex_unlock(&nullb_global_lock);
 
+	unregister_blkdev(null_major, "nullb");
+
 	if (tag_set.ops)
 		blk_mq_free_tag_set(&tag_set);
 
-- 
2.52.0