Re: [PATCH] x86: always define DECLARE_PCI_UNMAP* macros

[Jesse Barnes <jbarnes@virtuousgeek.org>]

On Thursday, November 27, 2008 3:45 am Ingo Molnar wrote:
> * Joerg Roedel <joerg.roedel@amd.com> wrote:
> > Currently these macros evaluate to a no-op except the kernel is
> > compiled with GART or Calgary support. But we also need these macros
> > when we have SWIOTLB, VT-d or AMD IOMMU in the kernel. Since we
> > always compile at least with SWIOTLB we can define these macros
> > always. This patch is also for stable backport for the same reason
> > the SWIOTLB default selection patch is.
> >
> > Cc: stable@kernel.org
> > Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
> > ---
> >  arch/x86/include/asm/pci_64.h |   14 --------------
> >  1 files changed, 0 insertions(+), 14 deletions(-)
>
> applied to tip/x86/urgent (for v2.6.28), as this is a DMA mapping
> bugfix for IOMMUs. If the AMD IOMMU is turned on in the .config but
> CONFIG_GART_IOMMU is off (a rare but possible combo), we'd leak on
> unmap and crash the box quickly.
>
> Jesse, is that path of upstream merge fine with you?

Yeah, that's fine with me.  OTOH removing config options generally seems like 
a good idea too, so maybe this combination should just be disallowed.  Or is 
there a good reason for this type of config?

-- 
Jesse Barnes, Intel Open Source Technology Center