Re: [PATCH v6 04/12] arm64/mm: Export set_direct_map_*_noflush() APIs

[Thierry Reding]

On Wed, Sep 09, 2026 at 10:51:43PM -0700, Christoph Hellwig wrote:
> On Fri, Sep 04, 2026 at 12:44:55PM +0200, Thierry Reding wrote:
> > From: Thierry Reding <treding@xxxxxxxxxx>
> > 
> > Drivers that use this may want to be built as a module, so export them.
> 
> That's one of the worst commit log ever.  No, we don't just export
> core symbols dealing with the kernel direct map because
> "Drivers that use this may want to be built as a module".
> 
> For one exporting this at all needs a very good justification and
> not just hand waiving.  But more importantly if we can't avoid
> exporting it, it needs to be exported at the tightest sensible
> scope.  E.g. for a given module if it is so special, or a namespace
> if it's not that special.  But in doubt we should have a proper
> core abstraction instead of opening up direct map manipulation to
> random modules.

Fair points. In an earlier set of patches this was abstracted behind a
set of set_memory_*() functions, modelled after set_memory_encrypted()
and set_memory_decrypted(), which I think I'd still prefer, too.

Is that more along the lines of what you had in mind?

Thanks,
Thierry

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