Comment 11 for bug 1572630

At first glance, theses 2 commits are needed to fix the issue, 897bb0c7 is the fix but won't build if e0e827b9, since it removes the function "queue_for_each_ctx" that will no longer be defined in the header file after "897bb0c7".

e0e827b9 blk-mq: Reuse hardware context cpumask for tags
897bb0c7 blk-mq: Use proper cpumask iterator