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Date:   Wed, 8 Sep 2021 07:26:03 +0100
From:   Christoph Hellwig <hch@infradead.org>
To:     Shunsuke Mie <mie@igel.co.jp>
Cc:     Zhu Yanjun <zyjzyj2000@gmail.com>,
        Christian K??nig <christian.koenig@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
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        Doug Ledford <dledford@redhat.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Jianxin Xiong <jianxin.xiong@intel.com>,
        Leon Romanovsky <leon@kernel.org>,
        linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org,
        dhobsong@igel.co.jp, taki@igel.co.jp, etom@igel.co.jp
Subject: Re: [RFC PATCH 1/3] RDMA/umem: Change for rdma devices has not dma
 device
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On Wed, Sep 08, 2021 at 03:16:09PM +0900, Shunsuke Mie wrote:
> To share memory space using dma-buf, a API of the dma-buf requires dma
> device, but devices such as rxe do not have a dma device. For those case,
> change to specify a device of struct ib instead of the dma device.

So if dma-buf doesn't actually need a device to dma map why do we ever
pass the dma_device here?  Something does not add up.