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Subject: Re: [PATCH v9 13/13] nvmet: Optionally use PCI P2P memory
To:     Christoph Hellwig <hch@lst.de>,
        Logan Gunthorpe <logang@deltatee.com>
Cc:     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,
        Stephen Bates <sbates@raithlin.com>,
        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>,
        =?UTF-8?Q?Christian_K=c3=b6nig?= <christian.koenig@amd.com>,
        Jens Axboe <axboe@kernel.dk>,
        Steve Wise <swise@opengridcomputing.com>
References: <20181004212747.6301-1-logang@deltatee.com>
 <20181004212747.6301-14-logang@deltatee.com>
 <a3af4bda-0b73-c964-c7d6-5d59f0710768@grimberg.me>
 <2bcc0927-83ab-1bf2-d584-aebd5274cefa@deltatee.com>
 <20181005070720.GA23725@lst.de>
From:   Sagi Grimberg <sagi@grimberg.me>
Message-ID: <236ae882-34e0-50d8-ac19-ee5dab8db3f2@grimberg.me>
Date:   Fri, 5 Oct 2018 00:34:06 -0700
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>>>> +static inline struct device *nvmet_ns_dev(struct nvmet_ns *ns)
>>>> +{
>>>> +	return disk_to_dev(ns->bdev->bd_disk);
>>>> +}
>>>
>>> This needs to handle non bdev namespaces.
>>
>> As it's coded now the helper never gets called unless ns->bdev is not
>> null. But in general, yes you are right, we should probably return NULL
>> if ns->bdev is NULL.
> 
> I'd rather skip that for now.

If there is a v10 I don't see why that cannot be addressed.

>>> index ef286b72d958..3d12f5f4568d 100644
>>> --- a/drivers/nvme/target/fc.c
>>> +++ b/drivers/nvme/target/fc.c
>>> @@ -2280,6 +2280,7 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport
>>> *tgtport,
>>>           fod->req.cmd = &fod->cmdiubuf.sqe;
>>>           fod->req.rsp = &fod->rspiubuf.cqe;
>>>           fod->req.port = tgtport->pe->port;
>>> +       fod->req.p2p_client = tgtport->dev;
>>>
>>>           /* clear any response payload */
>>>           memset(&fod->rspiubuf, 0, sizeof(fod->rspiubuf));
>>> --
>>
>> Sure, I guess that makes sense. I've never tried it with fc hardware but
>> I assume there's no reason it wouldn't work.
>>
>> I'll queue these changes up for a v10.
> 
> And I'd wait until someone has actually tested this case.

Oh yes, agreed. Should work though...