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From:   John Stultz <john.stultz@linaro.org>
Date:   Mon, 28 Oct 2019 15:23:57 -0700
Message-ID: <CALAqxLVW8KQVKwu=AY5Hkv7m9_L6djDy8h0se46MA+t_9_CCgg@mail.gmail.com>
Subject: Re: [RFC][PATCH 1/2] mm: cma: Export cma symbols for cma heap as a module
To:     Christoph Hellwig <hch@infradead.org>
Cc:     lkml <linux-kernel@vger.kernel.org>,
        Sandeep Patil <sspatil@google.com>,
        Laura Abbott <labbott@redhat.com>,
        Benjamin Gaignard <benjamin.gaignard@linaro.org>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        Liam Mark <lmark@codeaurora.org>,
        Pratik Patel <pratikp@codeaurora.org>,
        Brian Starkey <Brian.Starkey@arm.com>,
        "Andrew F . Davis" <afd@ti.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Yue Hu <huyue2@yulong.com>, Mike Rapoport <rppt@linux.ibm.com>,
        Chenbo Feng <fengc@google.com>,
        Alistair Strachan <astrachan@google.com>,
        Hridya Valsaraju <hridya@google.com>,
        dri-devel <dri-devel@lists.freedesktop.org>
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On Mon, Oct 28, 2019 at 11:39 AM John Stultz <john.stultz@linaro.org> wrote:
> On Mon, Oct 28, 2019 at 12:46 AM Christoph Hellwig <hch@infradead.org> wrote:
> >
> > On Fri, Oct 25, 2019 at 11:48:33PM +0000, John Stultz wrote:
> > >  struct cma *dma_contiguous_default_area;
> > > +EXPORT_SYMBOL(dma_contiguous_default_area);
> >
> > Please CC the dma maintainer.  And no, you have no business using this.
>
> Sure thing. And I'll look again to see why I was needing to pull that
> one in to get it to build.

Ah. So looking a bit closer, I'm needing this due to my using
dev_get_cma_area()  to get the default cma area for the dmabuf
cma_heap.

Do you have a suggestion for how to get a reference to the default CMA
area without exporting dma_contiguous_default_area? Would it be
preferred to move dev_get_cma_area() into the .c file and
EXPORT_SYMBOL_GPL that function?

thanks
-john