On Sat, 2017-09-02 at 21:08 +0800, Ming Lei wrote: > --- a/include/linux/blkdev.h > +++ b/include/linux/blkdev.h > @@ -565,6 +565,10 @@ struct request_queue { > > int bypass_depth; > atomic_t mq_freeze_depth; > + spinlock_t freeze_lock; > + unsigned normal_freezing:1; > + unsigned preempt_freezing:1; > + unsigned preempt_unfreezing:1; > > #if defined(CONFIG_BLK_DEV_BSG) > bsg_job_fn *bsg_job_fn; Requests queues already have to many states and you want to make request queues even more complicated by introducing several new state variables? Yikes! Bart.