Re: [patch 2/2] mspec driver

[Nick Piggin]

Jes Sorensen wrote:
> > > > > > "Nick" == Nick Piggin <nickpiggin@xxxxxxxxxxxx> writes:
>
>
> Nick> Jes Sorensen wrote:
>
> > > + vma->vm_flags |= (VM_IO | VM_LOCKED | VM_RESERVED | VM_PFNMAP);
>
>
> Nick> VM_PFNMAP actually has a fairly specific meaning [unlike the
> Nick> rest of them :)] so you should be careful with it. Actually if
> Nick> you set vm_pgoff in the right way, then that should enable you
> Nick> to do COWs on these areas if that is what you want.
>
> Yup, I went through that when I started using it. I think you guided
> me through it :-)
>
> We don't want COW here as the access is backed by special behavior in
> the memory controller. We only allow shared mappings for that reason.

No problem, I think you should just stop using the VM_PFNMAP flag then.
[Linus should jump in here if I'm wrong ;)]

--
SUSE Labs, Novell Inc.
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