And this way is correct because quiesce is enough for driver to handle
error recovery. The only difference is where to wait during error recovery.
With this way, IO is just queued in block layer queue instead of
__bio_queue_enter(), finally waiting for completion is done in upper
layer. Either way, IO can't move on during error recovery.
The point was to contain the fallout from modifying the hctx mappings.
If you allow IO to queue in the blk-mq layer while a reset is in
progress, they may be entering a context that won't be as expected on
the other side of the reset.
That still happens to *some* commands though right?
