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

Benjamin Herrenschmidt benh at kernel.crashing.org
Thu Sep 1 15:35:11 EST 2011

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 :-)

I'm a bit late for producing a powerpc-next (due to travelling).


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