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Date:   Thu, 21 May 2020 18:16:00 -0700
From:   Matthew Wilcox <willy@infradead.org>
To:     John Hubbard <jhubbard@nvidia.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>, jgg@ziepe.ca,
        Liam.Howlett@oracle.com, daniel.m.jordan@oracle.com,
        dave@stgolabs.net, hughd@google.com, jglisse@redhat.com,
        ldufour@linux.ibm.com, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, peterz@infradead.org, rientjes@google.com,
        vbabka@suse.cz, walken@google.com, yinghan@google.com
Subject: Re: [PATCH] mm/gup: might_lock_read(mmap_sem) in
 get_user_pages_fast()
Message-ID: <20200522011600.GJ28818@bombadil.infradead.org>
References: <20200522010443.1290485-1-jhubbard@nvidia.com>
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On Thu, May 21, 2020 at 06:04:43PM -0700, John Hubbard wrote:
> Instead of scattering these assertions across the drivers,
> do this assertion inside the core of get_user_pages_fast*()
> functions. That also includes pin_user_pages_fast*()
> routines.
> 
> Add a might_lock_read(mmap_sem) call to internal_get_user_pages_fast().
> 
> Suggested-by: Matthew Wilcox <willy@infradead.org>

Yup, this is exactly what I meant.  Feel free to transform this into
an Acked-by: or Reviewed-by: if that's the appropriate tag.

Thanks, John!