From: Jason Gunthorpe <jgg@ziepe.ca>
To: Oded Gabbay <oded.gabbay@gmail.com>
Cc: "Oded Gabbay" <ogabbay@kernel.org>,
"Linux-Kernel@Vger. Kernel. Org" <linux-kernel@vger.kernel.org>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
"Christian König" <christian.koenig@amd.com>,
"Daniel Vetter" <daniel.vetter@ffwll.ch>,
"Gal Pressman" <galpress@amazon.com>,
sleybo@amazon.com,
"Maling list - DRI developers" <dri-devel@lists.freedesktop.org>,
linux-rdma <linux-rdma@vger.kernel.org>,
"Linux Media Mailing List" <linux-media@vger.kernel.org>,
"Doug Ledford" <dledford@redhat.com>,
"Dave Airlie" <airlied@gmail.com>,
"Alex Deucher" <alexander.deucher@amd.com>,
"Leon Romanovsky" <leonro@nvidia.com>,
"Christoph Hellwig" <hch@lst.de>,
"amd-gfx list" <amd-gfx@lists.freedesktop.org>,
"moderated list:DMA BUFFER SHARING FRAMEWORK"
<linaro-mm-sig@lists.linaro.org>,
"Tomer Tayar" <ttayar@habana.ai>
Subject: Re: [PATCH v4 2/2] habanalabs: add support for dma-buf exporter
Date: Tue, 6 Jul 2021 10:54:51 -0300 [thread overview]
Message-ID: <20210706135451.GM4604@ziepe.ca> (raw)
In-Reply-To: <CAFCwf100mkROMw9+2LgW7d3jKnaeZ4nmfWm7HtXuUE7NF4B8pg@mail.gmail.com>
On Tue, Jul 06, 2021 at 12:44:49PM +0300, Oded Gabbay wrote:
> > > + /* In case we got a large memory area to export, we need to divide it
> > > + * to smaller areas because each entry in the dmabuf sgt can only
> > > + * describe unsigned int.
> > > + */
> >
> > Huh? This is forming a SGL, it should follow the SGL rules which means
> > you have to fragment based on the dma_get_max_seg_size() of the
> > importer device.
> >
> hmm
> I don't see anyone in drm checking this value (and using it) when
> creating the SGL when exporting dmabuf. (e.g.
> amdgpu_vram_mgr_alloc_sgt)
For dmabuf the only importer is RDMA and it doesn't care, but you
certainly should not introduce a hardwired constant instead of using
the correct function.
Jason
next prev parent reply other threads:[~2021-07-06 15:12 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-05 13:03 [PATCH v4 0/2] Add p2p via dmabuf to habanalabs Oded Gabbay
2021-07-05 13:03 ` [PATCH v4 1/2] habanalabs: define uAPI to export FD for DMA-BUF Oded Gabbay
2021-07-05 13:03 ` [PATCH v4 2/2] habanalabs: add support for dma-buf exporter Oded Gabbay
2021-07-05 16:52 ` Jason Gunthorpe
2021-07-06 9:44 ` Oded Gabbay
2021-07-06 13:54 ` Jason Gunthorpe [this message]
2021-07-06 8:40 ` [PATCH v4 0/2] Add p2p via dmabuf to habanalabs Daniel Vetter
2021-07-06 10:03 ` Oded Gabbay
2021-07-06 10:36 ` Daniel Vetter
2021-07-06 10:47 ` Daniel Vetter
2021-07-06 12:07 ` Daniel Vetter
2021-07-06 13:44 ` Jason Gunthorpe
2021-07-06 14:09 ` Daniel Vetter
2021-07-06 14:56 ` Jason Gunthorpe
2021-07-06 15:52 ` Daniel Vetter
2021-07-06 12:23 ` Christoph Hellwig
2021-07-06 14:23 ` Jason Gunthorpe
2021-07-06 14:39 ` Daniel Vetter
2021-07-06 15:25 ` Jason Gunthorpe
2021-07-06 15:49 ` Daniel Vetter
2021-07-06 16:07 ` Daniel Vetter
2021-07-06 17:28 ` Jason Gunthorpe
2021-07-06 17:31 ` Christoph Hellwig
2021-07-06 17:59 ` Jason Gunthorpe
2021-07-09 14:47 ` Dennis Dalessandro
2021-07-06 16:29 ` Jason Gunthorpe
2021-07-06 17:35 ` Daniel Vetter
2021-07-06 18:03 ` Daniel Vetter
2021-07-06 18:31 ` Jason Gunthorpe
2021-07-06 19:06 ` Daniel Vetter
2021-07-06 19:09 ` Alex Deucher
2021-07-06 12:21 ` Christoph Hellwig
2021-07-06 12:23 ` [Linaro-mm-sig] " Daniel Vetter
2021-07-06 12:45 ` Oded Gabbay
2021-07-06 13:17 ` Daniel Vetter
2021-07-06 13:45 ` Oded Gabbay
2021-07-07 12:17 ` Christian König
2021-07-07 12:54 ` Daniel Vetter
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