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 <20211207171447.GA6467@ziepe.ca>
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From:   Shunsuke Mie <mie@igel.co.jp>
Date:   Fri, 10 Dec 2021 20:29:24 +0900
Message-ID: <CANXvt5rCayOcengPr7Z_aFmJaXwWj9VcWZbaHnuHj6=2CkPndA@mail.gmail.com>
Subject: Re: [RFC PATCH v4 0/2] RDMA/rxe: Add dma-buf support
To:     Jason Gunthorpe <jgg@ziepe.ca>
Cc:     Zhu Yanjun <zyjzyj2000@gmail.com>,
        =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        Doug Ledford <dledford@redhat.com>,
        Jianxin Xiong <jianxin.xiong@intel.com>,
        Leon Romanovsky <leon@kernel.org>,
        Maor Gottlieb <maorg@nvidia.com>,
        Sean Hefty <sean.hefty@intel.com>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org,
        linux-media@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-rdma <linux-rdma@vger.kernel.org>,
        Damian Hobson-Garcia <dhobsong@igel.co.jp>,
        Takanari Hayama <taki@igel.co.jp>,
        Tomohito Esaki <etom@igel.co.jp>
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Hi Jason,
Thank you for replying.

2021=E5=B9=B412=E6=9C=888=E6=97=A5(=E6=B0=B4) 2:14 Jason Gunthorpe <jgg@zie=
pe.ca>:
>
> On Fri, Dec 03, 2021 at 12:51:44PM +0900, Shunsuke Mie wrote:
> > Hi maintainers,
> >
> > Could you please review this patch series?
>
> Why is it RFC?
>
> I'm confused why this is useful?
>
> This can't do copy from MMIO memory, so it shouldn't be compatible
> with things like Gaudi - does something prevent this?
I think if an export of the dma-buf supports vmap, CPU is able to access th=
e
mmio memory.

Is it wrong? If this is wrong, there is no advantages this changes..
>
> Jason

Regards,
Shunsuke