[RFC 3/3] mm: iommu: The Virtual Contiguous Memory Manager

[Zach Pfeffer]

On Thu, Jul 22, 2010 at 01:47:36PM +0900, FUJITA Tomonori wrote:
> On Wed, 21 Jul 2010 20:50:26 -0700
> Zach Pfeffer <zpfeffer at codeaurora.org> wrote:
> 
> > On Wed, Jul 14, 2010 at 10:59:43AM +0900, FUJITA Tomonori wrote:
> > > On Tue, 13 Jul 2010 10:02:23 +0100
> > > 
> > > Zach Pfeffer said this new VCM infrastructure can be useful for
> > > video4linux. However, I don't think we need 3,000-lines another
> > > abstraction layer to solve video4linux's issue nicely.
> > 
> > Its only 3000 lines because I haven't converted the code to use
> > function pointers.
> 
> The main point is adding a new abstraction that don't provide the huge
> benefit.

I disagree. In its current form the API may not be appropriate for
inclusion into the kernel, but it provides a common framework for
handling a class of problems that have been solved many times in the
kernel: large buffer management, IOMMU interoperation and fine grained
mapping control.