Re: [PATCH 18/23] AMD IOMMU: simplify dma_mask_to_pages

[Joerg Roedel <joerg.roedel@amd.com>]

On Thu, Sep 18, 2008 at 04:20:20AM +0900, FUJITA Tomonori wrote:
> On Wed, 17 Sep 2008 18:52:52 +0200
> Joerg Roedel <joerg.roedel@amd.com> wrote:
> 
> > The current calculation is very complicated. This patch replaces it with
> > a much simpler version.
> > 
> > Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
> > ---
> >  arch/x86/kernel/amd_iommu.c |    3 +--
> >  1 files changed, 1 insertions(+), 2 deletions(-)
> 
> I think that you can use iommu_device_max_index() for what
> dma_mask_to_pages does.

Hmm, in theory yes. But iommu_device_max_index() returns a size in bytes
and not in pages. So I still need to do the page shift somewhere. This
eliminates somewhat the benefit in this particular case.

Joerg

-- 
           |           AMD Saxony Limited Liability Company & Co. KG
 Operating |         Wilschdorfer Landstr. 101, 01109 Dresden, Germany
 System    |                  Register Court Dresden: HRA 4896
 Research  |              General Partner authorized to represent:
 Center    |             AMD Saxony LLC (Wilmington, Delaware, US)
           | General Manager of AMD Saxony LLC: Dr. Hans-R. Deppe, Thomas McCoy