I took at stab at the series this morning, and fixed the fabrics crash (blk_mq_alloc_request_hctx passed the cpumask of a NULL hctx), and pre-loaded a bunch of cļeanups to let your changes fit in better. Let me know what you think, the git branch is here: git://git.infradead.org/users/hch/block.git blk-mq-hotplug Gitweb: http://git.infradead.org/users/hch/block.git/shortlog/refs/heads/blk-mq-hotplug