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From:   John Stultz <john.stultz@linaro.org>
Date:   Mon, 4 Nov 2019 11:00:08 -0800
Message-ID: <CALAqxLXq=4dw=WfJZhXh=Ft3SHK1QUJZRt+rwy4ZuKTbjZUEpQ@mail.gmail.com>
Subject: Re: [RFC][PATCH 2/2] dma-buf: heaps: Allow system & cma heaps to be
 configured as a modules
To:     Daniel Vetter <daniel@ffwll.ch>
Cc:     lkml <linux-kernel@vger.kernel.org>,
        Sandeep Patil <sspatil@google.com>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Chenbo Feng <fengc@google.com>,
        Alistair Strachan <astrachan@google.com>,
        Liam Mark <lmark@codeaurora.org>, Yue Hu <huyue2@yulong.com>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        "Andrew F . Davis" <afd@ti.com>,
        Hridya Valsaraju <hridya@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Pratik Patel <pratikp@codeaurora.org>
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On Mon, Nov 4, 2019 at 2:24 AM Daniel Vetter <daniel@ffwll.ch> wrote:
> On Fri, Oct 25, 2019 at 11:48:34PM +0000, John Stultz wrote:
> > Allow loading system and cma heap as a module instead of just as
> > a statically built in heap.
> >
> > Since there isn't a good mechanism for dmabuf lifetime tracking
> > it isn't safe to allow the heap drivers to be unloaded, so these
> > drivers do not implement any module unloading functionality and
> > will show up in lsmod as "[permanent]".
>
> dma-buf itself has all the try_module_get we'll need ... why is this not
> possible?

Let me look into that.  Thanks for the pointer.

thanks
-john