Re: [PATCH v4 3/7] block: Convert RQF_PREEMPT into REQ_PREEMPT

[Christoph Hellwig]

This looks ok to me, or at least better than the version from Ming to
archive the same.  I kinda hate to add more REQ_* flags than
really nessecary though.  Maybe instead of the mapping to REQ_* as
suggested to ming blk_queue_enter should instead take the BLK_MQ_REQ_*
flags and we'll add BLK_MQ_REQ_PREEMPT, and pass those to
blk_get_request.  If it wasn't for Linus beeing angry due to block
churn I'd be very tempted to suggest that.