Re: can device drivers return non-ram via vm_ops->nopage?

[Jeff Garzik <jgarzik@pobox.com>]

Linus Torvalds wrote:
> In fact, on a lot of architectures (well, at least x86, and likely
> anything else that doesn't use any IOTLB and just allocates a chunk of
> physical memory), I think the "map_dma_coherent()" thing should basically
> just become a "remap_page_range()". Ie something like
> 
> 	#define map_dma_coherent(vma, vaddr, len) \
> 		remap_page_range(vma, vma->vm_start, __pa(vaddr), len, vma->vm_page_prot)
> 
> for the simple case.


That would be nice, though the reason I avoided remap_page_range() in 
via82cxxx_audio is that it discourages S/G.  Because remap_page_range() 
is easier and more portable, several drivers allocate one-big-area and 
then create an S/G list describing individual portions of that area.

I want to avoid that.  Most decent h/w is s/g these days.

	Jeff