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Date:   Tue, 2 May 2023 10:10:51 -0300
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     Christian Borntraeger <borntraeger@linux.ibm.com>
Cc:     Lorenzo Stoakes <lstoakes@gmail.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
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        Oleg Nesterov <oleg@redhat.com>,
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        Theodore Ts'o <tytso@mit.edu>, Peter Xu <peterx@redhat.com>,
        Matthew Rosato <mjrosato@linux.ibm.com>
Subject: Re: [PATCH v6 3/3] mm/gup: disallow FOLL_LONGTERM GUP-fast writing
 to file-backed mappings
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On Tue, May 02, 2023 at 03:04:27PM +0200, Christian Borntraeger wrote:
\> > We can reintroduce a flag to permit exceptions if this is really broken, are you
> > able to test? I don't have an s390 sat around :)
> 
> Matt (Rosato on cc) probably can. In the end, it would mean having
>   <memoryBacking>
>     <source type="file"/>
>   </memoryBacking>

This s390 code is the least of the problems, after this series VFIO
won't startup at all with this configuration.

Jason