Re: [PATCH v1 1/5] block: introduce bio_clone_bioset_partial()

[Christoph Hellwig]

On Tue, Feb 14, 2017 at 09:04:26AM +0800, Ming Lei wrote:
> On Mon, Feb 13, 2017 at 9:46 PM, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> > On Fri, Feb 10, 2017 at 06:56:13PM +0800, Ming Lei wrote:
> >> md still need bio clone(not the fast version) for behind write,
> >> and it is more efficient to use bio_clone_bioset_partial().
> >>
> >> The idea is simple and just copy the bvecs range specified from
> >> parameters.
> >
> > Given how few users bio_clone_bioset has I wonder if we shouldn't
> > simply add the two new arguments to it instead of adding another
> > indirection.
> 
> For md write-behind, looks we have to provide the two arguments,
> could you explain a bit how we can do that by adding another indirection?

I meant to just pass the additional arguments that 
bio_clone_bioset_partial has to bio_clone_bioset.