Re: [PULL] topic/iomem-mmap-vs-gup

From: Stephen Rothwell
Date: Mon May 17 2021 - 18:05:00 EST


Hi Daniel,

On Mon, 17 May 2021 17:29:35 +0200 Daniel Vetter <daniel.vetter@xxxxxxxx> wrote:
>
> On Mon, May 10, 2021 at 9:30 AM Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> >
> > On Mon, May 10, 2021 at 09:16:58AM +0200, Daniel Vetter wrote:
> > > > End result: not pulling it, unless somebody can explain to me in small
> > > > words why I'm wrong and have the mental capacity of a damaged rodent.
> > >
> > > No rodents I think, just more backstory of how this all fits. tldr;
> > > pin_user_pages is the only safe use of this vb2 userptr thing.
> >
> > Yes, which is why I advocate for just ripping the follow_pfn path
> > out entirely. It could have been used for crazy ad dangerous peer to
> > peer transfers outside of any infrastructure making it safe, or for
> > pre-CMA kernel memory carveouts for lage contiguous memory allocations
> > (which are pretty broken by design as well). So IMHO the only sensible
> > thing is to remove this cruft entirely, and if it breaks a currently
> > working setup (which I think is unlikely) we'll have to make sure it
> > can work the proper way.
>
> Since I'm not getting any cozy consenus vibes here on any option I
> think I'll just drop this.
>
> Stephen, can you pls drop
>
> git://anongit.freedesktop.org/drm/drm topic/iomem-mmap-vs-gup
>
> from linux-next? It's not going anywhere. I'll also go ahead and
> delete the branch, to make sure you catch this update :-)

I have dropped this now. Thanks for letting me know.

--
Cheers,
Stephen Rothwell

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