Christoph Hellwig [off-list ref] writes:

On Wed, Oct 31, 2018 at 12:09:29AM +1100, Benjamin Herrenschmidt wrote:

quoted

On Tue, 2018-10-30 at 13:58 +0100, Christoph Hellwig wrote:

quoted

Please take my patch instead.  We have a kernel polcity to not keep
dead code around, and everyone including Linus and the attending IBMers
confirmed this.

Let's call a cat a cat ... ;-)

It's not *dead* code. It's code that is used by an out of tree driver
(which also happen not to be open source).

(Actually that part of the driver is MIT licensed, but yes other parts
 are not open source.)

Which clearly makes it a derived work of the kernel if it uses an
interface just create for it, and thus even more important to remove
it to not get anyone into legal trouble.

We don't want driver code calling into firmware, that's the job of
platform code, so we would need the same API (or something similar) for
a GPL driver.

cheers