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Date:   Mon, 16 Nov 2020 16:27:44 +0000
From:   Christoph Hellwig <hch@infradead.org>
To:     "Michael S. Tsirkin" <mst@redhat.com>
Cc:     Christoph Hellwig <hch@infradead.org>,
        Alexander Lobakin <alobakin@pm.me>,
        Amit Shah <amit@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Arnaud Pouliquen <arnaud.pouliquen@st.com>,
        Suman Anna <s-anna@ti.com>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Ohad Ben-Cohen <ohad@wizery.com>,
        Jason Wang <jasowang@redhat.com>,
        virtualization@lists.linux-foundation.org,
        linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org
Subject: Re: [PATCH virtio] virtio: virtio_console: fix DMA memory allocation
 for rproc serial
Message-ID: <20201116162744.GA16619@infradead.org>
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 <20201116091950.GA30524@infradead.org>
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On Mon, Nov 16, 2020 at 04:51:49AM -0500, Michael S. Tsirkin wrote:
> On Mon, Nov 16, 2020 at 09:19:50AM +0000, Christoph Hellwig wrote:
> > I just noticed this showing up in Linus' tree and I'm not happy.
> > 
> > This whole model of the DMA subdevices in remoteproc is simply broken.
> > 
> > We really need to change the virtio code pass an expicit DMA device (
> > similar to what e.g. the USB and RDMA code does),
> 
> Could you point me at an example or two please?

Take a look at the ib_dma_* helper in include/rdma/ib_verbs.h and
dma_device member in struct ib_device for the best example.