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From: Logan Gunthorpe <logang@deltatee.com>
Message-ID: <7d276107-d2ae-530b-3d56-e104e22b4eea@deltatee.com>
Date: Mon, 8 Jan 2018 12:05:57 -0700
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Subject: Re: [PATCH 06/12] IB/core: Add optional PCI P2P flag to
 rdma_rw_ctx_[init|destroy]()
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To: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>, Keith Busch <keith.busch@intel.com>, linux-nvdimm@lists.01.org, linux-rdma@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, Jason Gunthorpe <jgg@ziepe.ca>, =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= <jglisse@redhat.com>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, Bjorn Helgaas <bhelgaas@google.com>, Max Gurtovoy <maxg@mellanox.com>
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On 08/01/18 11:57 AM, Christoph Hellwig wrote:
> It does, sort of - but in a different way then the normal DMA map
> ops.  And only to work around the fact that we need to map our
> P2P space into struct pages.  Without that we could just pass the
> bus address around, but the Linux stack and VM isn't anywhere near
> ready for something that advanced.

Yeah, wouldn't that be nice.

Ok, so if we shouldn't touch the dma_map infrastructure how should the 
workaround to opt-out HFI and QIB look? I'm not that familiar with the 
RDMA code.

Thanks,

Logan
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