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Date:   Sat, 27 Feb 2021 09:44:36 +0000
From:   Christoph Hellwig <hch@infradead.org>
To:     Daniel Vetter <daniel@ffwll.ch>
Cc:     John Stultz <john.stultz@linaro.org>,
        lkml <linux-kernel@vger.kernel.org>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Christian Koenig <christian.koenig@amd.com>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        Liam Mark <lmark@codeaurora.org>,
        Chris Goldsworthy <cgoldswo@codeaurora.org>,
        Laura Abbott <labbott@kernel.org>,
        Brian Starkey <Brian.Starkey@arm.com>,
        Hridya Valsaraju <hridya@google.com>,
        Suren Baghdasaryan <surenb@google.com>,
        Sandeep Patil <sspatil@google.com>,
        Daniel Mentz <danielmentz@google.com>,
        ??rjan Eide <orjan.eide@arm.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Ezequiel Garcia <ezequiel@collabora.com>,
        Simon Ser <contact@emersion.fr>,
        James Jones <jajones@nvidia.com>,
        "open list:DMA BUFFER SHARING FRAMEWORK" 
        <linux-media@vger.kernel.org>,
        dri-devel <dri-devel@lists.freedesktop.org>
Subject: Re: [PATCH] dma-buf: heaps: Set VM_PFNMAP in mmap for system and cma
 heaps
Message-ID: <20210227094436.GA3130571@infradead.org>
References: <20210226040908.3274666-1-john.stultz@linaro.org>
 <CAKMK7uHGutJiZ879NAweTHka=gZQBw9zWQSDJn6bTLS6bJwvvg@mail.gmail.com>
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On Fri, Feb 26, 2021 at 08:36:55AM +0100, Daniel Vetter wrote:
> Also given that both deal with struct page there's a ton of divergence
> between these two that doesn't make much sense. Maybe could even share
> the code fully, aside from how you allocate the struct pages.

I've been saying that since the code was first submitted.  Once pages
are allocated from CMA they should be treated not different from normal
pages.

Please take a look at how the DMA contigous allocator manages to share
all code for handling CMA vs alloc_pages pages.