Re: PATCH 2.6.21-rc1 aoe: handle zero _count pages in bios

From: Andrew Morton
Date: Fri Mar 02 2007 - 00:01:12 EST


On Fri, 2 Mar 2007 04:49:10 +0000 Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:

> On Thu, Mar 01, 2007 at 08:48:06PM -0800, Andrew Morton wrote:
> > On Fri, 2 Mar 2007 04:30:39 +0000 Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> >
> > > But in this case we'd really need to enforce this, and add a
> > > BUG_ON(PageSlab(page)) in bio_add_page to trip everyone submit
> > > this kind of pages.
> >
> > That would be
> >
> > BUG_ON(PageSlab(page) && page_count(page) == 0)?
>
> No, all slab pages. Currently they all have a reference count of
> zero, but we generally don't want people to pass in pages that
> come from a non-refcounted allocator.

I that case we're talking about different things.

I thought the proposal was to continue to use slab pages, but to take a ref
on them as they're added to the bio, drop that ref in bi_end_io()?

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