From: Christoph Hellwig <hch@infradead.org>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Christoph Hellwig <hch@infradead.org>,
Daniel Vetter <daniel@ffwll.ch>,
Jianxin Xiong <jianxin.xiong@intel.com>,
linux-rdma@vger.kernel.org, dri-devel@lists.freedesktop.org,
Leon Romanovsky <leon@kernel.org>,
Doug Ledford <dledford@redhat.com>,
Daniel Vetter <daniel.vetter@intel.com>,
Christian Koenig <christian.koenig@amd.com>
Subject: Re: [PATCH v6 1/4] RDMA/umem: Support importing dma-buf as user memory region
Date: Tue, 27 Oct 2020 08:08:16 +0000 [thread overview]
Message-ID: <20201027080816.GA2692@infradead.org> (raw)
In-Reply-To: <20201026122637.GQ36674@ziepe.ca>
On Mon, Oct 26, 2020 at 09:26:37AM -0300, Jason Gunthorpe wrote:
> On Sat, Oct 24, 2020 at 08:48:07AM +0100, Christoph Hellwig wrote:
> > On Fri, Oct 23, 2020 at 03:20:05PM -0300, Jason Gunthorpe wrote:
> > > The problem is we have RDMA drivers that assume SGL's have a valid
> > > struct page, and these hacky/wrong P2P sgls that DMABUF creates cannot
> > > be passed into those drivers.
> >
> > RDMA drivers do not assume scatterlist have a valid struct page,
> > scatterlists are defined to have a valid struct page. Any scatterlist
> > without a struct page is completely buggy.
>
> It is not just having the struct page, it needs to be a CPU accessible
> one for memcpy/etc. They aren't correct with the
> MEMORY_DEVICE_PCI_P2PDMA SGLs either.
Exactly.
next prev parent reply other threads:[~2020-10-27 8:08 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-23 16:39 [PATCH v6 0/4] RDMA: Add dma-buf support Jianxin Xiong
2020-10-23 16:39 ` [PATCH v6 1/4] RDMA/umem: Support importing dma-buf as user memory region Jianxin Xiong
2020-10-23 16:49 ` Daniel Vetter
2020-10-23 18:09 ` Xiong, Jianxin
2020-10-23 18:13 ` Daniel Vetter
2020-10-23 18:20 ` Jason Gunthorpe
2020-10-24 1:45 ` Daniel Vetter
2020-11-03 17:36 ` Xiong, Jianxin
2020-11-03 20:43 ` Daniel Vetter
2020-11-04 0:01 ` Xiong, Jianxin
2020-11-05 15:02 ` Jason Gunthorpe
2020-10-24 7:48 ` Christoph Hellwig
2020-10-26 12:26 ` Jason Gunthorpe
2020-10-27 8:08 ` Christoph Hellwig [this message]
2020-10-27 17:32 ` Xiong, Jianxin
2020-10-27 19:51 ` Jason Gunthorpe
2020-10-27 20:00 ` Jason Gunthorpe
2020-10-27 20:11 ` Xiong, Jianxin
2020-10-23 16:39 ` [PATCH v6 2/4] RDMA/core: Add device method for registering dma-buf base " Jianxin Xiong
2020-10-23 16:40 ` [PATCH v6 3/4] RDMA/uverbs: Add uverbs command for dma-buf based MR registration Jianxin Xiong
2020-10-23 16:40 ` [PATCH v6 4/4] RDMA/mlx5: Support dma-buf based userspace memory region Jianxin Xiong
2020-10-27 20:08 ` Jason Gunthorpe
2020-10-27 20:33 ` Xiong, Jianxin
2020-10-28 16:35 ` Jason Gunthorpe
2020-10-28 17:29 ` Xiong, Jianxin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201027080816.GA2692@infradead.org \
--to=hch@infradead.org \
--cc=christian.koenig@amd.com \
--cc=daniel.vetter@intel.com \
--cc=daniel@ffwll.ch \
--cc=dledford@redhat.com \
--cc=dri-devel@lists.freedesktop.org \
--cc=jgg@ziepe.ca \
--cc=jianxin.xiong@intel.com \
--cc=leon@kernel.org \
--cc=linux-rdma@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).