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Subject: Re: [PATCH v2 08/10] nvme-pci: Add support for P2P memory in requests
To:     Logan Gunthorpe <logang@deltatee.com>,
        linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
        linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org,
        linux-nvdimm@lists.01.org, linux-block@vger.kernel.org
Cc:     Stephen Bates <sbates@raithlin.com>,
        Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
        Keith Busch <keith.busch@intel.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Jason Gunthorpe <jgg@mellanox.com>,
        Max Gurtovoy <maxg@mellanox.com>,
        Dan Williams <dan.j.williams@intel.com>,
        =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= <jglisse@redhat.com>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Alex Williamson <alex.williamson@redhat.com>
References: <20180228234006.21093-1-logang@deltatee.com>
 <20180228234006.21093-9-logang@deltatee.com>
From:   Sagi Grimberg <sagi@grimberg.me>
Message-ID: <c6639530-48ba-4655-c772-7d88a030e37e@grimberg.me>
Date:   Thu, 1 Mar 2018 13:07:41 +0200
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> For P2P requests we must use the pci_p2pmem_[un]map_sg() functions
> instead of the dma_map_sg functions.
> 
> With that, we can then indicate PCI_P2P support in the request queue.
> For this, we create an NVME_F_PCI_P2P flag which tells the core to
> set QUEUE_FLAG_PCI_P2P in the request queue.

This looks fine to me,

Reviewed-by: Sagi Grimberg <sagi@grimberg.me>

Any plans adding the capability to nvme-rdma? Should be
straight-forward... In theory, the use-case would be rdma backend
fabric behind. Shouldn't be hard to test either...