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Date:   Tue, 30 Oct 2018 14:24:02 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc:     Christoph Hellwig <hch@lst.de>,
        Alistair Popple <alistair@popple.id.au>,
        linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        mpe@ellerman.id.au
Subject: Re: [PATCH] powerpc/npu-dma: Remove NPU DMA ops
Message-ID: <20181030132401.GC30783@lst.de>
References: <20181030110203.27257-1-alistair@popple.id.au> <20181030125841.GB30158@lst.de> <30359cc433e97739d93e13717b2897e462895097.camel@kernel.crashing.org>
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On Wed, Oct 31, 2018 at 12:09:29AM +1100, Benjamin Herrenschmidt wrote:
> On Tue, 2018-10-30 at 13:58 +0100, Christoph Hellwig wrote:
> > 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).

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.