[PATCH V2 6/6] null_blk: free global tag_set on init error path

[Zizhi Wo]

From: Zizhi Wo <wozizhi@xxxxxxxxxx>

If shared_tags is enabled, null_setup_tagset() allocates the global tag_set
via null_init_global_tag_set(). If device creation later fails, err_dev
destroys the default devices and calls unregister_blkdev(), but never frees
the global tag_set. Since module init failed, null_exit() is never invoked,
so the global tag_set's tags and maps are permanently leaked.

Free the global tag_set in err_dev, matching null_exit() which does
if (tag_set.ops) blk_mq_free_tag_set(&tag_set).

Fixes: 82f402fefa50 ("null_blk: add support for shared tags")
Signed-off-by: Zizhi Wo <wozizhi@xxxxxxxxxx>
---
 drivers/block/null_blk/main.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index e7555c47b671..1e24c7e23524 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -2187,6 +2187,8 @@ static int __init null_init(void)
 		null_destroy_dev(nullb);
 	}
 	unregister_blkdev(null_major, "nullb");
+	if (tag_set.ops)
+		blk_mq_free_tag_set(&tag_set);
 	return ret;
 }
 
-- 
2.52.0