Sorry for the late reply,

On Thu, 01 Sep 2011 15:35:11 +1000
Benjamin Herrenschmidt [off-list ref] wrote:

On Wed, 2011-06-29 at 17:19 +0900, FUJITA Tomonori wrote:

quoted

On Fri, 24 Jun 2011 12:05:23 -0700
Nishanth Aravamudan [off-list ref] wrote:

quoted

From: Milton Miller <redacted>

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.

 .../...

quoted

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,