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From:   John Stultz <john.stultz@linaro.org>
Date:   Mon, 28 Oct 2019 15:26:28 -0700
Message-ID: <CALAqxLWp3F-_uKrtW06CApyqajL-DK0Rujku8YjHe8QEUcXU6w@mail.gmail.com>
Subject: Re: [RFC][PATCH 1/2] mm: cma: Export cma symbols for cma heap as a module
To:     Sandeep Patil <sspatil@google.com>
Cc:     lkml <linux-kernel@vger.kernel.org>,
        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 Morton <akpm@linux-foundation.org>,
        Chenbo Feng <fengc@google.com>,
        Hridya Valsaraju <hridya@google.com>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        "Andrew F . Davis" <afd@ti.com>, Yue Hu <huyue2@yulong.com>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Alistair Strachan <astrachan@google.com>
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On Mon, Oct 28, 2019 at 1:03 PM John Stultz <john.stultz@linaro.org> wrote:
>
> On Mon, Oct 28, 2019 at 12:12 PM <sspatil@google.com> wrote:
> > On Fri, Oct 25, 2019 at 11:48:33PM +0000, John Stultz wrote:
> > > --- a/kernel/dma/contiguous.c
> > > +++ b/kernel/dma/contiguous.c
> > > @@ -31,6 +31,7 @@
> > >  #endif
> > >
> > >  struct cma *dma_contiguous_default_area;
> > > +EXPORT_SYMBOL(dma_contiguous_default_area);
> >
> > I didn't need to do this for the (out-of-tree) ion cma heap [1].
> > Any reason why you had to?
>
> Its likely due to the changes I made in the separate
> non-default-CMA-region patch set. Earlier I had gotten away with just
> your change, but in testing before I sent this series, I hit the build
> error and quickly added the export before sending.

And just to clarify this point, I was mistaken and it wasn't the
non-default-CMA-region patch set, but the fact that I'm using
dev_get_cma_area(NULL) to get the default CMA area to register, rather
then trying to register every CMA area via cma_for_each_area() as is
done in ION.  I actually could probably drop the cma_for_each_area
export for the dmabuf heaps usage.

thanks
-john