On Fri, Nov 16, 2018 at 06:05:21AM -0800, Greg Kroah-Hartman wrote: > On Fri, Nov 16, 2018 at 07:23:10PM +0800, Ming Lei wrote: > > @@ -456,7 +456,7 @@ struct request_queue { > > /* > > * mq queue kobject > > */ > > - struct kobject mq_kobj; > > + struct kobject *mq_kobj; > > What is this kobject even used for? It wasn't obvious at all from this > patch, why is it needed if you are not using it to reference count the > larger structure here? All attributes and kobjects under /sys/block/$DEV/mq are covered by this kobject actually, and all are for exposing blk-mq specific information, but now there is only blk-mq, and legacy io path is removed. That is why I mentioned we may remove this kobject last time and move all under /sys/block/$DEV/queue, however you thought that may break some userspace. If we want to backport them to stable, this patch may be a bit easier to go. Thanks, Ming