[PATCH 2/4] dma-mapping: add get_required_mask if arch overrides default

[FUJITA Tomonori]

Sorry for the late reply,

On Thu, 01 Sep 2011 15:35:11 +1000
Benjamin Herrenschmidt <benh at kernel.crashing.org> wrote:

> On Wed, 2011-06-29 at 17:19 +0900, FUJITA Tomonori wrote:
> > On Fri, 24 Jun 2011 12:05:23 -0700
> > Nishanth Aravamudan <nacc at us.ibm.com> wrote:
> > 
> > > From: Milton Miller <miltonm at bga.com>
> > > 
> > > If an architecture sets ARCH_HAS_DMA_GET_REQUIRED_MASK and has settable
> > > dma_map_ops, the required mask may change by the ops implementation.
> > > For example, a system that always has an mmu inline may only require 32
> > > bits while a swiotlb would desire bits to cover all of memory.
> > > 
> > > Therefore add the field if the architecture does not use the generic
> > > definition of dma_get_required_mask. The first use will by by powerpc.
> > > Note that this does add some dependency on the order in which files are
> > > visible here.
> 
>  .../...
> 
> > If you add get_required_mask to dma_map_ops, we should clean up ia64
> > too and implement the generic proper version in
> > dma-mapping-common.h. Then we kill ARCH_HAS_DMA_GET_REQUIRED_MASK
> > ifdef hack. Otherwise, I don't think it makes sense to add this to
> > dma_map_ops.
> 
> In the meantime, can I have an ack so I can include this along with the
> rest of Milton's patches ? It's been around for a while now :-)

Sure, we can clean up this later.

Thanks,