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

From: Ming Lei
Date: Tue Feb 14 2017 - 21:26:47 EST

On Wed, Feb 15, 2017 at 12:01 AM, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> 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.

That may cause more changes(fs, ...) into this patchset, so I suggest to
do that in another patchset, especially after we confirmed current
users of bio_clone is absolutely necessary, and I will check if other bio_clone
can be converted to fast clone.

Ming Lei