On Thu, Sep 12, 2019 at 08:57:29AM +0800, Ming Lei wrote: > Could you explain a bit why we can't do that? > > The segment size limit is basically removed since the following commit > 200a9aff7b02 ("block: remove the segment size check in bio_will_gap"). > > Before that commit, the max segment size limit worked. No, it didn't as explained in the commit log. It worked for some cases but not others.