Re: ZONE_DMA

Christoph Lameter
2006-09-22T18:32:50Z

On Fri, 22 Sep 2006, Jesse Barnes wrote:

> Oh, it's already there in the tree, but obviously some drivers still need
> to be converted. See Documentation/DMA-API.txt. It's not PCI specific
> like the old PCI DMA interface (Documentation/DMA-mapping.txt) and
> provides a way for drivers to specify their addressing limitations
> (dma_supported and dma_set_mask), which allows the underlying architecture
> code to report a failure if necessary.

AFAICT this is dealing with special dma issues and not with the problem of
allocating memory for a certain supported address range from the page
allocator. From the first glance at the docs it looks as if it is relying
on __GFP_DMAxx to get the allocations right. I think the code could be
changed though to call a new page allocator function to get the right
memory and that would work for all devices using that API.