On 11/5/19 1:49 AM, Daniel Vetter wrote:

On Mon, Nov 04, 2019 at 11:20:38AM -0800, John Hubbard wrote:

quoted

On 11/4/19 10:10 AM, Daniel Vetter wrote:

quoted

On Thu, Oct 31, 2019 at 04:36:28PM -0700, Ira Weiny wrote:

quoted

On Wed, Oct 30, 2019 at 03:49:20PM -0700, John Hubbard wrote:

quoted

Convert drm/via to use the new pin_user_pages_fast() call, which sets
FOLL_PIN. Setting FOLL_PIN is now required for code that requires
tracking of pinned pages, and therefore for any code that calls
put_user_page().

Reviewed-by: Ira Weiny <ira.weiny@intel.com>

No one's touching the via driver anymore, so feel free to merge this
through whatever tree suits best (aka I'll drop this on the floor and
forget about it now).

Acked-by: Daniel Vetter <redacted>

OK, great. Yes, in fact, I'm hoping Andrew can just push the whole series
in through the mm tree, because that would allow it to be done in one 
shot, in 5.5

btw is there more? We should have a bunch more userptr stuff in various
drivers, so was really surprised that drm/via is the only thing in your
series.

There is more, but:

1) Fortunately, the opt-in nature of FOLL_PIN allows converting a few call
sites at a time. And so this patchset limits itself to converting the bare
minimum required to get started, which is: 

    a) calls sites that have already been converted to put_user_page(), 
       and

    b) call sites that set FOLL_LONGTERM.

So yes, follow-up patches will be required. This is not everything.
In fact, if I can fix this series up quickly enough that it makes it into
mmotm soon-ish, then there may be time to get some follow-patches on top
of it, in time for 5.5.


2) If I recall correctly, Jerome and maybe others are working to remove
as many get_user_pages() callers from drm as possible, and instead use
a non-pinned page approach, with mmu notifiers instead.  I'm not sure of
the exact status of that work, but I see that etnaviv, amdgpu, i915, and
radeon still call gup() in linux-next.

Anyway, some of those call sites will disappear. Although I'd expect a 
few to remain, because I doubt the simpler GPUs can support page faulting.



thanks,

John Hubbard
NVIDIA