Re: [PATCH V5 5/8] block: add check on elevator for supporting bio merge via hashtable from blk-mq sw queue

[Christoph Hellwig]

On Sat, Sep 30, 2017 at 07:26:52PM +0800, Ming Lei wrote:
> blk_mq_sched_try_merge() will be reused in following patches
> to support bio merge to blk-mq sw queue, so add checkes to
> related functions which are called from blk_mq_sched_try_merge().

The changes themselves look ok, but don't make sense on their own,
I think this needs to be merged with the code tor actually introduce
the bio merge.