Re: [PATCH 1/5] mm: return valid info from hmm_range_unregister

From: Christoph Hellwig
Date: Wed Jul 03 2019 - 16:29:01 EST


On Wed, Jul 03, 2019 at 07:00:50PM +0000, Jason Gunthorpe wrote:
> I don't think the API should be encouraging some shortcut here..
>
> We can't do the above pattern because the old hmm_vma API didn't allow
> it, which is presumably a reason why it is obsolete.
>
> I'd rather see drivers move to a consistent pattern so we can then
> easily hoist the seqcount lock scheme into some common mmu notifier
> code, as discussed.

So you don't like the version in amdgpu_ttm_tt_get_user_pages_done in
linux-next either?

I can remove this and just move hmm_vma_range_done to nouveau instead.
Let me know if you have other comments before I resend. Note that
I'll probably be offline Thu-Sun this week.