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Subject: Re: [PATCH for-next 2/4] RDMA/hns: Add IOMMU enable support in hip08
To: Christoph Hellwig <hch@infradead.org>, Jason Gunthorpe <jgg@ziepe.ca>
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From: "Wei Hu (Xavier)" <xavier.huwei@huawei.com>
Message-ID: <5A03AEC3.10109@huawei.com>
Date: Thu, 9 Nov 2017 09:26:27 +0800
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On 2017/11/7 23:58, Christoph Hellwig wrote:
> On Tue, Nov 07, 2017 at 08:48:38AM -0700, Jason Gunthorpe wrote:
>> Can't you just use vmalloc and dma_map that? Other drivers follow that
>> approach..
> You can't easily due to the flushing requirements.  We used to do that
> in XFS and it led to problems.  You need the page allocator + vmap +
> invalidate_kernel_vmap_range + flush_kernel_vmap_range to get the
> cache flushing right.
>
> .
Hi, Christoph Hellwig
    Thanks for your suggestion.
    Regards
Wei Hu