[PATCH] NVMe: Remove remnants of cpu hotplug

[Sam Bradshaw (sbradshaw)]

> I'm curious with the num_possible -> num_online change. This should be
> handled by blk-mq, so no worries there. But how did it trigger the
> unset CPU in the run mask? Ran into the same issue here on a different
> test case, just curious if you looked into this.

After looking into it, the issue has been fixed on your for-3.19/core 
branch due to:

[PATCH] blk-mq: prevent unmapped hw queue from being scheduled

It's straightforward enough to test that the fix works by setting 
possible_cpus on the kernel command line to something larger than 
online cpus.