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Subject: Re: [PATCH 00/34] put_user_pages(): miscellaneous call sites
To:     Ira Weiny <ira.weiny@intel.com>, Michal Hocko <mhocko@kernel.org>
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From:   John Hubbard <jhubbard@nvidia.com>
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On 8/7/19 7:36 PM, Ira Weiny wrote:
> On Wed, Aug 07, 2019 at 10:46:49AM +0200, Michal Hocko wrote:
>> On Wed 07-08-19 10:37:26, Jan Kara wrote:
>>> On Fri 02-08-19 12:14:09, John Hubbard wrote:
>>>> On 8/2/19 7:52 AM, Jan Kara wrote:
>>>>> On Fri 02-08-19 07:24:43, Matthew Wilcox wrote:
>>>>>> On Fri, Aug 02, 2019 at 02:41:46PM +0200, Jan Kara wrote:
>>>>>>> On Fri 02-08-19 11:12:44, Michal Hocko wrote:
>>>>>>>> On Thu 01-08-19 19:19:31, john.hubbard@gmail.com wrote:
  [...]
> Before I go on, I would like to say that the "imbalance" of get_user_pages()
> and put_page() bothers me from a purist standpoint...  However, since this
> discussion cropped up I went ahead and ported my work to Linus' current master
> (5.3-rc3+) and in doing so I only had to steal a bit of Johns code...  Sorry
> John...  :-(
> 
> I don't have the commit messages all cleaned up and I know there may be some
> discussion on these new interfaces but I wanted to throw this series out there
> because I think it may be what Jan and Michal are driving at (or at least in
> that direction.
> 
> Right now only RDMA and DAX FS's are supported.  Other users of GUP will still
> fail on a DAX file and regular files will still be at risk.[2]
> 
> I've pushed this work (based 5.3-rc3+ (33920f1ec5bf)) here[3]:
> 
> https://github.com/weiny2/linux-kernel/tree/linus-rdmafsdax-b0-v3
> 
> I think the most relevant patch to this conversation is:
> 
> https://github.com/weiny2/linux-kernel/commit/5d377653ba5cf11c3b716f904b057bee6641aaf6
> 

ohhh...can you please avoid using the old __put_user_pages_dirty()
function? I thought I'd caught things early enough to get away with
the rename and deletion of that. You could either:

a) open code an implementation of vaddr_put_pages_dirty_lock() that
doesn't call any of the *put_user_pages_dirty*() variants, or

b) include my first patch ("") are part of your series, or

c) base this on Andrews's tree, which already has merged in my first patch.


thanks,
-- 
John Hubbard
NVIDIA