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

[Christoph Hellwig]

On Thu, Mar 01, 2007 at 09:00:44PM -0800, Andrew Morton wrote:
> 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()?

That would give you silent memory corruption in case the networking code
hold a reference after the memory gets returned to slab and reused.

We need to either stop allowing to pass slab memory to the block layer,
or document that drivers need to handle it specially and give them a
way to find out about them. (Or do the horrible slab refcounting hack
I wrote up above)

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