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From:   Tony Luck <tony.luck@gmail.com>
Date:   Wed, 2 Jan 2019 13:53:33 -0800
Message-ID: <CA+8MBb+9prWYSmp25K-LMUv1_0eekvFqXhoj87CV9zcaXfMDGg@mail.gmail.com>
Subject: Re: [PATCH 02/15] swiotlb: remove dma_mark_clean
To:     Christoph Hellwig <hch@lst.de>
Cc:     iommu@lists.linux-foundation.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Jesper Dangaard Brouer <brouer@redhat.com>,
        Tariq Toukan <tariqt@mellanox.com>,
        Ilias Apalodimas <ilias.apalodimas@linaro.org>,
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        Robin Murphy <robin.murphy@arm.com>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Fenghua Yu <fenghua.yu@intel.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Keith Busch <keith.busch@intel.com>,
        Jonathan Derrick <jonathan.derrick@intel.com>,
        linux-pci@vger.kernel.org,
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On Fri, Dec 7, 2018 at 11:08 AM Christoph Hellwig <hch@lst.de> wrote:
>
> Instead of providing a special dma_mark_clean hook just for ia64, switch
> ia64 to use the normal arch_sync_dma_for_cpu hooks instead.
>
> This means that we now also set the PG_arch_1 bit for pages in the
> swiotlb buffer, which isn't stricly needed as we will never execute code
> out of the swiotlb buffer, but otherwise harmless.

ia64 build based on arch/ia64/configs/zx1_defconfig now fails with undefined
symbols arch_dma_alloc and arch_dma_free (used by kernel/dma/direct.c).

This config doesn't define CONFIG_SWIOTLB, so we don't get the
benefit of the routines in arch/ia64/kernel/dma-mapping.c

-Tony