Re: [PATCH 2/3] block: unexport blk_rq_append_bio

[Boaz Harrosh <bharrosh@panasas.com>]

FUJITA Tomonori wrote:
> On Wed, 11 Feb 2009 17:07:16 +0200
> Boaz Harrosh <bharrosh@panasas.com> wrote:
> 
>>>
>>>
>> Sure it can pass pages to ULD but then how ULD maks a request out of
>> pages?
> 
> If you extend blk_rq_map_kern as James did, your ULD make a request
> out of passed pages, that is, the block layer properly builds a
> request with bio(s).

What? I don't understand?
blk_rq_map_kern takes a kernel-pointer and length, how to pass array
of page* ?

> 
> I think that another possible option is adding a new mapping function
> that can handle multiple bios for kernel buffers (as Mike extended
> blk_rq_map_user).
> 

Yes adding a new mapping function can help. Please note I need to
add (append) pages same as bio_add_pc_page() but on request level.

And yet we had an entry that did exactly that, blk_rq_append_bio(), no?

> 
>> And it gets more complicated then that (above multiple times)
> 
> I don't think so. If you don't have time to work on it, please let me
> know. I'll fix OSD ULD.

I have all the time in the world, And yes what James did with blk_rq_map_kern
will help with appending other osd segments on top of data.

If you propose the appropriate new API for block request level I can implement
that in block, and also in OSD. What other entry you want to add/change that solve
my need?

Thanks
Boaz