Messages in this thread | | | Date | Thu, 1 Mar 2007 21:09:42 -0800 | From | Andrew Morton <> | Subject | Re: PATCH 2.6.21-rc1 aoe: handle zero _count pages in bios |
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On Fri, 2 Mar 2007 05:03:51 +0000 Christoph Hellwig <hch@infradead.org> wrote:
> 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.
Well, given that bi_end_io() is called after the "io" has completed, I'm assuming that networking has completely finished with the memory by the time bi_end_io() gets called.
I guess one can envisage situations where that might not happen, but they'd be terribly buggy ones, surely.
> 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)
OK. So you're proposing that XFS and ext3 simply stop sing slab for this memory?
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