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From: Greg Kroah-Hartman <>
To: Alexey Kardashevskiy <>
Cc: Christoph Hellwig <>,
	Benjamin Herrenschmidt <>,
	Paul Mackerras <>,
	Michael Ellerman <>,
	Oliver O'Halloran <>,
	Frederic Barrat <>,,
Subject: Re: [PATCH 3/4] powerpc/powernv: remove unused NPU DMA code
Date: Fri, 28 Jun 2019 00:51:16 +0800
Message-ID: <> (raw)
In-Reply-To: <>

On Thu, Jun 27, 2019 at 09:22:40AM +0200, Christoph Hellwig wrote:
> On Thu, Jun 27, 2019 at 10:21:55AM +1000, Alexey Kardashevskiy wrote:
> > > Which comment?  Last time I asked you complaint "it is still used in
> > > exactly the same way as before" which you later clarified that you
> > > have a hidden out of tree user somewhere, and you only objected to
> > 
> > It is not hidden, anyone can download and inspect that GPL driver.
> For one no one has ever posted a link.  And second as mentioned
> countless times it doesn't matter, it only matters if it is in mainline,
> or as a special exception actively trying to go mainline.
> > > the word "dead".  That has been fixed and there were no further
> > > comments.
> > 
> > You still have it in the cover letter so at very least 3/4 is not a part
> > of this patchset then.
> > 
> > And I still want to see a formal statement about out-of-tree drivers
> > support/tolerance. If you manage to remove this code, I'll have to post
> > a revert (again and again) but I would rather know the exact list of
> > what we do and what we do not do about such drivers and if the list 1)
> > exists 2) is reasonable then I could try to come up with a better
> > solution or point others to the policy and push them to do the right
> > thing. Right now it is just you pretending that the nVidia driver does
> > not exist, this is not helping. Thanks,
> We had that discussion at kernel summit and it was reported.  Anyway,
> adding Greg, who usually has some pretty good prewritten letters for
> this kind of thing.

I used to have one but it's been so long since anyone tried to even
think about defending the removal of functions that are not used in the
kernel tree anymore, that I can't seem to find it anymore :)

Christoph is completely correct here, if it isn't in the tree, it
doesn't matter.  We have made this "formal" statement again and again
over the years, starting with the old "stable api nonsense" document
that is in the kernel tree itself.

And he is also correct in that we talked about this specific issue, in
detail, at the maintainers summit last year, see for the details
if you somehow missed it then.


greg k-h

  reply index

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-25 14:52 remove unused powernv code v3 Christoph Hellwig
2019-06-25 14:52 ` [PATCH 1/4] powerpc/powernv: remove the unused pnv_pci_set_p2p function Christoph Hellwig
2019-07-03 14:27   ` Michael Ellerman
2019-07-03 14:33     ` Christoph Hellwig
2019-06-25 14:52 ` [PATCH 2/4] powerpc/powernv: remove the unused tunneling exports Christoph Hellwig
2019-06-25 14:52 ` [PATCH 3/4] powerpc/powernv: remove unused NPU DMA code Christoph Hellwig
2019-06-26  0:44   ` Alexey Kardashevskiy
2019-06-26  7:49     ` Christoph Hellwig
2019-06-27  0:21       ` Alexey Kardashevskiy
2019-06-27  7:22         ` Christoph Hellwig
2019-06-27 16:51           ` Greg Kroah-Hartman [this message]
2019-06-25 14:52 ` [PATCH 4/4] powerpc/powernv: remove the unused vas_win_paste_addr and vas_win_id functions Christoph Hellwig
  -- strict thread matches above, loose matches on Subject: below --
2019-06-25  8:15 remove unused powernv code v2 Christoph Hellwig
2019-06-25  8:15 ` [PATCH 3/4] powerpc/powernv: remove unused NPU DMA code Christoph Hellwig

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