Re: [PATCH] SPARC64: fix iommu sg chaining

[Jens Axboe <jens.axboe@oracle.com>]

On Wed, Oct 17 2007, David Miller wrote:
> From: Jens Axboe <jens.axboe@oracle.com>
> Date: Wed, 17 Oct 2007 12:58:40 +0200
> 
> > The problem is that you cannot zero the entire sg entry, because then
> > you'd potentially overwrite the chain pointer.
> > 
> > I'd propose just adding a
> > 
> >         sg_dma_address(sg) = 0;
> >         sg_dma_len(sg) = 0;
> > 
> > there for now, or provide an arch_clear_sg_entry() helper if we need
> > more killed.
> 
> The "chain pointer" is indicated by an sg->page with the low
> bit set, but we're explicitly initializing it here to a
> non-chain page pointer value.
> 
> What's the problem?

See next mail :-)

-- 
Jens Axboe