When the blk-mq debugfs file creation logic was "cleaned up" it was cleaned up too much, causing the queue file to not be created in the correct location. Turns out the check for the directory being present is needed as if that has not happened yet, the files should not be created, and the function will be called later on in the initialization code so that the files can be created in the correct location.

Fixes: 6cfc0081b046 ("blk-mq: no need to check return value of debugfs_create functions") Reported-by: Stephen Rothwell sfr@canb.auug.org.au Cc: Jens Axboe axboe@kernel.dk Cc: linux-block@vger.kernel.org Cc: stable stable@vger.kernel.org # 5.2+ Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- block/blk-mq-debugfs.c | 7 +++++++ 1 file changed, 7 insertions(+)

diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c index 2489ddbb21db..3afe327f816f 100644 --- a/block/blk-mq-debugfs.c +++ b/block/blk-mq-debugfs.c @@ -934,6 +934,13 @@ void blk_mq_debugfs_register_sched(struct request_queue *q) { struct elevator_type *e = q->elevator->type;

+ /* + * If the parent directory has not been created yet, return, we will be + * called again later on and the directory/files will be created then. + */ + if (!q->debugfs_dir) + return; + if (!e->queue_debugfs_attrs) return;