On Sat, Sep 30, 2017 at 02:12:11PM +0800, Ming Lei wrote:

We need to pass PREEMPT flags to blk_queue_enter()
for allocating request with RQF_PREEMPT in the
following patch.

I don't like having another name space for flags.  It seems like
we should simply pass ops on, and then map the nowait allocations
to RQF_PREEMPT to REQ_PREEMPT as done in the series from Bart.