Re: [PATCHSET pata-2.6] ide: rq->buffer, data, special and misc cleanups

[Jeff Garzik]

FUJITA Tomonori wrote:
> On Tue, 31 Mar 2009 16:04:39 +0300
> Boaz Harrosh <bharrosh@xxxxxxxxxxx> wrote:
>
> > > I
> > > just don't think bvec should be used outside of block/fs interface.
> > > As I wrote before, non-FS users have no reason to worry about bio.
> > > All it should think about is the requst it needs to issue and the
> > > memory area it's gonna use as in/out buffers.  bio just doesn't have a
> > > place there.
> > I don't understand what happens to all the people that start to work on the block
> > layer, they start getting defensive about bio being private to the request
> > level. But the Genie is out of the bag already (I know cats and bottles).
> > bio is already heavily used above the block layer from directly inside filesystems
> > to all kind of raid engines, DM MD managers, multi paths, integrity information ...
> >
> > Because bio is exactly that Ideal page carrier you are talking about.
>
> Wrong. multi path doesn't use bio. md accesses to the bio internal
> (it's not nice) and has the own way to carry pages. dm has the own
> mechanism on the top of bio. And bio doesn't work nicely for file
> systems such as btrfs, which handle multiple devices.
>
> Please stop your wrong argument 'bio is the ideal page carrier'.

What is the multi-device problem with bio?

The idea behind bio is to be the ideal page carrier :)  It sounds like 
bio needs revision, not abandonment.

	Jeff



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