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

[Linus Torvalds]

On Mon, 22 Mar 2004, Andrea Arcangeli wrote:
>
> On Sun, Mar 21, 2004 at 11:58:54PM +0000, Russell King wrote:
> > On Sun, Mar 21, 2004 at 03:51:31PM -0800, Linus Torvalds wrote:
> > > That might be the minimal fix, since it would basically involve:
> > >  - change whatever offensive "virt_to_page()" calls into 
> > >    "dma_map_to_page()".
> > >  - implement "dma_map_to_page()" for all architectures.
> > > 
> > > Would that make people happy?
> > 
> > Unfortunately this doesn't make dwmw2 happy - he claims to have machines
> > which implement dma_alloc_coherent using RAM which doesn't have any
> > struct page associated with it.
> 
> I would suggest to add a ->nopage_dma (or whatever other name for an
> additional callback in the vm_ops) that will return a non pageable "pfn"

No.

Fix the broken architecture instead.

		Linus
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