To review this properly I had to actually squatch patches 2-4 and 6-9 into a single patch to read nicely over it, the result is attached below. That one has one minor issue in __blk_drain_queue where a newly added indent uses 4 spaces instead of tabs, but otherwise everything in this series looks fine to me and passes sanity testing with scsi-mq. Reviewed-by: Christoph Hellwig