From: Logan Gunthorpe <logang@deltatee.com>
To: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>
Cc: "Alex Williamson" <alex.williamson@redhat.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,
"Jérôme Glisse" <jglisse@redhat.com>,
"Jason Gunthorpe" <jgg@mellanox.com>,
"Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Max Gurtovoy" <maxg@mellanox.com>,
"Christian König" <christian.koenig@amd.com>
Subject: Re: [PATCH v5 07/13] block: Add PCI P2P flag for request queue and check support for requests
Date: Wed, 5 Sep 2018 14:09:55 -0600 [thread overview]
Message-ID: <eb42fb94-9da6-955b-8524-0a0f5ac4bd19@deltatee.com> (raw)
In-Reply-To: <20180905201152.GA1893@lst.de>
On 05/09/18 02:11 PM, Christoph Hellwig wrote:
> On Wed, Sep 05, 2018 at 01:54:31PM -0600, Jens Axboe wrote:
>> On 9/5/18 1:56 PM, Christoph Hellwig wrote:
>>> On Wed, Sep 05, 2018 at 01:45:04PM -0600, Jens Axboe wrote:
>>>> The point is that the caller doesn't necessarily know where the bio
>>>> will end up, hence the caller can't fully check if the whole stack
>>>> supports P2P.
>>>
>>> The caller must necessarily know where the bio will end up, as for P2P
>>> support we need to query if the bio target is P2P capable vs the
>>> source of the P2P memory.
>>
>> Then what's the point of having the check at all?
>
> Just an additional little safe guard. If you think it isn't worth
> it I guess we can just drop it for now.
Yes, the point is to prevent driver writers from doing the wrong thing
by not doing the necessary checks before submitting to the queue.
Logan
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next prev parent reply other threads:[~2018-09-05 20:10 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-30 18:53 [PATCH v5 00/13] Copy Offload in NVMe Fabrics with P2P PCI Memory Logan Gunthorpe
2018-08-30 18:53 ` [PATCH v5 01/13] PCI/P2PDMA: Support peer-to-peer memory Logan Gunthorpe
2018-08-31 8:04 ` Christian König
2018-08-31 15:48 ` Logan Gunthorpe
2018-09-01 8:27 ` Christoph Hellwig
2018-08-31 16:19 ` Jonathan Cameron
2018-08-31 16:26 ` Logan Gunthorpe
2018-08-30 18:53 ` [PATCH v5 02/13] PCI/P2PDMA: Add sysfs group to display p2pmem stats Logan Gunthorpe
2018-08-30 18:53 ` [PATCH v5 03/13] PCI/P2PDMA: Add PCI p2pmem DMA mappings to adjust the bus offset Logan Gunthorpe
2018-08-30 18:53 ` [PATCH v5 04/13] PCI/P2PDMA: Introduce configfs/sysfs enable attribute helpers Logan Gunthorpe
2018-08-30 18:53 ` [PATCH v5 05/13] docs-rst: Add a new directory for PCI documentation Logan Gunthorpe
2018-08-30 18:53 ` [PATCH v5 06/13] PCI/P2PDMA: Add P2P DMA driver writer's documentation Logan Gunthorpe
2018-08-31 0:34 ` Randy Dunlap
2018-08-31 15:44 ` Logan Gunthorpe
2018-08-31 8:08 ` Christian König
2018-08-31 15:51 ` Logan Gunthorpe
2018-08-31 17:38 ` Christian König
2018-08-31 19:11 ` Logan Gunthorpe
2018-08-30 18:53 ` [PATCH v5 07/13] block: Add PCI P2P flag for request queue and check support for requests Logan Gunthorpe
2018-08-30 19:11 ` Jens Axboe
2018-08-30 19:17 ` Logan Gunthorpe
2018-08-30 19:19 ` Jens Axboe
2018-09-01 8:28 ` Christoph Hellwig
2018-09-03 22:26 ` Logan Gunthorpe
2018-09-05 19:26 ` Jens Axboe
2018-09-05 19:33 ` Logan Gunthorpe
2018-09-05 19:45 ` Jens Axboe
2018-09-05 19:53 ` Logan Gunthorpe
2018-09-05 19:56 ` Christoph Hellwig
2018-09-05 19:54 ` Jens Axboe
2018-09-05 20:11 ` Christoph Hellwig
2018-09-05 20:09 ` Logan Gunthorpe [this message]
2018-09-05 20:14 ` Jens Axboe
2018-09-05 20:18 ` Logan Gunthorpe
2018-09-05 20:19 ` Jens Axboe
2018-09-05 20:32 ` Logan Gunthorpe
2018-09-05 20:36 ` Jens Axboe
2018-09-05 21:03 ` Logan Gunthorpe
2018-09-05 21:13 ` Christoph Hellwig
2018-09-05 21:18 ` Jens Axboe
2018-09-10 16:41 ` Christoph Hellwig
2018-09-10 18:11 ` Logan Gunthorpe
2018-09-11 7:10 ` Christoph Hellwig
2018-08-30 18:53 ` [PATCH v5 08/13] IB/core: Ensure we map P2P memory correctly in rdma_rw_ctx_[init|destroy]() Logan Gunthorpe
2018-08-31 0:18 ` Sagi Grimberg
2018-08-30 18:53 ` [PATCH v5 09/13] nvme-pci: Use PCI p2pmem subsystem to manage the CMB Logan Gunthorpe
2018-08-30 18:53 ` [PATCH v5 10/13] nvme-pci: Add support for P2P memory in requests Logan Gunthorpe
2018-09-04 15:16 ` Jason Gunthorpe
2018-09-04 15:47 ` Logan Gunthorpe
2018-09-05 19:22 ` Christoph Hellwig
2018-08-30 18:53 ` [PATCH v5 11/13] nvme-pci: Add a quirk for a pseudo CMB Logan Gunthorpe
2018-08-30 18:53 ` [PATCH v5 12/13] nvmet: Introduce helper functions to allocate and free request SGLs Logan Gunthorpe
2018-08-31 0:14 ` Sagi Grimberg
2018-08-30 18:53 ` [PATCH v5 13/13] nvmet: Optionally use PCI P2P memory Logan Gunthorpe
2018-08-31 0:25 ` Sagi Grimberg
2018-08-31 15:41 ` Logan Gunthorpe
2018-08-30 19:20 ` [PATCH v5 00/13] Copy Offload in NVMe Fabrics with P2P PCI Memory Jerome Glisse
2018-08-30 19:30 ` Logan Gunthorpe
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