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Date:   Thu, 7 Mar 2019 09:46:54 -0800
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Dan Williams <dan.j.williams@intel.com>
Cc:     Jerome Glisse <jglisse@redhat.com>, Linux MM <linux-mm@kvack.org>,
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Subject: Re: [PATCH 09/10] mm/hmm: allow to mirror vma of a file on a DAX
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On Tue, 5 Mar 2019 20:20:10 -0800 Dan Williams <dan.j.williams@intel.com> wrote:

> My hesitation would be drastically reduced if there was a plan to
> avoid dangling unconsumed symbols and functionality. Specifically one
> or more of the following suggestions:
> 
> * EXPORT_SYMBOL_GPL on all exports to avoid a growing liability
> surface for out-of-tree consumers to come grumble at us when we
> continue to refactor the kernel as we are wont to do.

The existing patches use EXPORT_SYMBOL() so that's a sticking point. 
Jerome, what would happen is we made these EXPORT_SYMBOL_GPL()?

> * A commitment to consume newly exported symbols in the same merge
> window, or the following merge window. When that goal is missed revert
> the functionality until such time that it can be consumed, or
> otherwise abandoned.

It sounds like we can tick this box.

> * No new symbol exports and functionality while existing symbols go unconsumed.

Unsure about this one?