Re: [11/36] Use page_cache_xxx in fs/buffer.c

Jens Axboe
2007-08-31T07:11:57Z

On Fri, Aug 31 2007, Christoph Lameter wrote:
> On Fri, 31 Aug 2007, Jens Axboe wrote:
>
> > > So if we try to push a too large buffer down with submit_bh() we get a
> > > failure.
> >
> > Only partly, you may be violating a number of other restrictions (size
> > is many things, not just length of the data).
>
> Could you be more specific?

Size of a single segment, for instance. Or if the bio crosses a dma
boundary. If your block is 64kb and the maximum segment size is 32kb,
then you would need to clone the bio and split it into two.

Things like that. This isn't a problem with single page requests, as we
based the lower possible boundaries on that.

--
Jens Axboe