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From:   Dan Williams <dan.j.williams@intel.com>
Date:   Tue, 27 Apr 2021 13:48:58 -0700
Message-ID: <CAPcyv4h-YVLHTCnXhTy5DVbhXndWZnhcKerDdS=+wDjWzZc4Fg@mail.gmail.com>
Subject: Re: [PATCH 00/16] Add new DMA mapping operation for P2PDMA
To:     John Hubbard <jhubbard@nvidia.com>
Cc:     Jason Gunthorpe <jgg@ziepe.ca>,
        Logan Gunthorpe <logang@deltatee.com>,
        linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
        linux-block@vger.kernel.org, linux-pci@vger.kernel.org,
        linux-mm@kvack.org, iommu@lists.linux-foundation.org,
        Stephen Bates <sbates@raithlin.com>,
        Christoph Hellwig <hch@lst.de>,
        =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>,
        Don Dutile <ddutile@redhat.com>,
        Matthew Wilcox <willy@infradead.org>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        Jakowski Andrzej <andrzej.jakowski@intel.com>,
        Minturn Dave B <dave.b.minturn@intel.com>,
        Jason Ekstrand <jason@jlekstrand.net>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Xiong Jianxin <jianxin.xiong@intel.com>,
        Bjorn Helgaas <helgaas@kernel.org>,
        Ira Weiny <ira.weiny@intel.com>,
        Robin Murphy <robin.murphy@arm.com>
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On Tue, Apr 27, 2021 at 1:22 PM John Hubbard <jhubbard@nvidia.com> wrote:
>
> On 4/27/21 12:28 PM, Jason Gunthorpe wrote:
> > On Thu, Apr 08, 2021 at 11:01:07AM -0600, Logan Gunthorpe wrote:
> >> Hi,
> >>
> >> This patchset continues my work to to add P2PDMA support to the common
> >> dma map operations. This allows for creating SGLs that have both P2PDMA
> >> and regular pages which is a necessary step to allowing P2PDMA pages in
> >> userspace.
> >>
> >> The earlier RFC[1] generated a lot of great feedback and I heard no show
> >> stopping objections. Thus, I've incorporated all the feedback and have
> >> decided to post this as a proper patch series with hopes of eventually
> >> getting it in mainline.
> >>
> >> I'm happy to do a few more passes if anyone has any further feedback
> >> or better ideas.
> >
> > For the user of the DMA API the idea seems reasonable enough, the next
> > steps to integrate with pin_user_pages() seem fairly straightfoward
> > too
> >
> > Was there no feedback on this at all?
> >
>
> oops, I meant to review this a lot sooner, because this whole p2pdma thing is
> actually very interesting and important...somehow it slipped but I'll take
> a look now.

Still in my queue as well behind Joao's memmap consolidation series,
and a recent copy_mc_to_iter() fix series from Al.