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From:   Gavin Li <gavinli@thegavinli.com>
Date:   Mon, 5 Aug 2019 19:55:44 -0700
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Subject: Re: [PATCH 1/2] dma-mapping: fix page attributes for dma_mmap_*
To:     Christoph Hellwig <hch@lst.de>
Cc:     Shawn Anastasio <shawn@anastas.io>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Russell King <linux@armlinux.org.uk>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Paul Burton <paul.burton@mips.com>,
        James Hogan <jhogan@kernel.org>, linuxppc-dev@lists.ozlabs.org,
        linux-mips@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, Gavin Li <git@thegavinli.com>
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>         /* create a coherent mapping */
>         ret = dma_common_contiguous_remap(page, size, VM_USERMAP,
> -                       arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs),
> +                       dma_pgprot(dev, PAGE_KERNEL, attrs),
>                         __builtin_return_address(0));
>         if (!ret) {
>                 __dma_direct_free_pages(dev, size, page);

Is dma_common_contiguous_remap() still necessary in the
DMA_ATTR_NON_CONSISTENT case? I would presume it would be fine to just
return a linearly mapped address in that case.