This supports passing NULL ops to blk_set_dev_ops()
so that we can remove stale ops in some cases.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
 block/block-backend.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/block-backend.c b/block/block-backend.c
index e0e1aff4b1..35457a6a1d 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -1062,7 +1062,7 @@ void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops,
     blk->dev_opaque = opaque;
 
     /* Are we currently quiesced? Should we enforce this right now? */
-    if (blk->quiesce_counter && ops->drained_begin) {
+    if (blk->quiesce_counter && ops && ops->drained_begin) {
         ops->drained_begin(opaque);
     }
 }
-- 
2.20.1