From: Logan Gunthorpe <logang@deltatee.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org,
Bjorn Helgaas <bhelgaas@google.com>,
Christian Koenig <Christian.Koenig@amd.com>,
Jason Gunthorpe <jgg@mellanox.com>,
Sagi Grimberg <sagi@grimberg.me>, Keith Busch <kbusch@kernel.org>,
Jens Axboe <axboe@fb.com>,
Dan Williams <dan.j.williams@intel.com>,
Eric Pilmore <epilmore@gigaio.com>,
Stephen Bates <sbates@raithlin.com>
Subject: Re: [PATCH 14/14] PCI/P2PDMA: Introduce pci_p2pdma_[un]map_resource()
Date: Thu, 25 Jul 2019 10:00:54 -0600 [thread overview]
Message-ID: <3d5400df-f109-9ffa-3e79-8f6bb8d7de34@deltatee.com> (raw)
In-Reply-To: <20190725115038.GC31065@lst.de>
On 2019-07-25 5:50 a.m., Christoph Hellwig wrote:
> On Wed, Jul 24, 2019 at 10:06:22AM -0600, Logan Gunthorpe wrote:
>> Yes. This is the downside of dealing only with a phys_addr_t: we have to
>> look up against it. Unfortunately, I believe it's possible for different
>> BARs on a device to be in different windows, so something like this is
>> necessary unless we already know the BAR the phys_addr_t belongs to. It
>> might probably be sped up a bit by storing the offsets of each bar
>> instead of looping through all the bridge windows, but I don't think it
>> will get you *that* much.
>>
>> As this is an example with no users, the answer here will really depend
>> on what the use-case is doing. If they can lookup, ahead of time, the
>> mapping type and offset then they don't have to do this work on the hot
>> path and it means that pci_p2pdma_map_resource() is simply not a
>> suitable API.
>
> Ok. So lets just keep this out as an RFC and don't merge it until an
> actual concrete user shows up.
Yup, that was my intention and I mentioned that in the commit message.
Logan
next prev parent reply other threads:[~2019-07-25 16:01 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-22 23:08 [PATCH 00/14] PCI/P2PDMA: Support transactions that hit the host bridge Logan Gunthorpe
2019-07-22 23:08 ` [PATCH 01/14] PCI/P2PDMA: Add constants for not-supported result upstream_bridge_distance() Logan Gunthorpe
2019-07-23 16:20 ` Koenig, Christian
2019-07-22 23:08 ` [PATCH 02/14] PCI/P2PDMA: Factor out __upstream_bridge_distance() Logan Gunthorpe
2019-07-22 23:08 ` [PATCH 03/14] PCI/P2PDMA: Apply host bridge white list for ACS Logan Gunthorpe
2019-07-23 16:23 ` Koenig, Christian
2019-07-22 23:08 ` [PATCH 04/14] PCI/P2PDMA: Cache the result of upstream_bridge_distance() Logan Gunthorpe
2019-07-22 23:08 ` [PATCH 05/14] PCI/P2PDMA: Factor out host_bridge_whitelist() Logan Gunthorpe
2019-07-22 23:08 ` [PATCH 06/14] PCI/P2PDMA: Add whitelist support for Intel Host Bridges Logan Gunthorpe
2019-07-25 18:52 ` Jason Gunthorpe
2019-07-25 19:14 ` Logan Gunthorpe
2019-07-22 23:08 ` [PATCH 07/14] PCI/P2PDMA: Add the provider's pci_dev to the dev_pgmap struct Logan Gunthorpe
2019-07-24 6:32 ` Christoph Hellwig
2019-07-24 15:50 ` Logan Gunthorpe
2019-07-25 6:02 ` Christoph Hellwig
2019-07-22 23:08 ` [PATCH 08/14] PCI/P2PDMA: Add attrs argument to pci_p2pdma_map_sg() Logan Gunthorpe
2019-07-22 23:08 ` [PATCH 09/14] PCI/P2PDMA: Introduce pci_p2pdma_unmap_sg() Logan Gunthorpe
2019-07-22 23:08 ` [PATCH 10/14] PCI/P2PDMA: Factor out __pci_p2pdma_map_sg() Logan Gunthorpe
2019-07-22 23:08 ` [PATCH 11/14] PCI/P2PDMA: dma_map P2PDMA map requests that traverse the host bridge Logan Gunthorpe
2019-07-24 6:32 ` Christoph Hellwig
2019-07-24 15:58 ` Logan Gunthorpe
2019-07-25 6:10 ` Christoph Hellwig
2019-07-25 16:00 ` Logan Gunthorpe
2019-07-25 16:34 ` Jason Gunthorpe
2019-07-25 17:22 ` Logan Gunthorpe
2019-07-25 18:58 ` Jason Gunthorpe
2019-07-25 19:17 ` Logan Gunthorpe
2019-07-25 19:29 ` Jason Gunthorpe
2019-07-25 19:36 ` Logan Gunthorpe
2019-07-22 23:08 ` [PATCH 12/14] PCI/P2PDMA: No longer require no-mmu for host bridge whitelist Logan Gunthorpe
2019-07-22 23:08 ` [PATCH 13/14] PCI/P2PDMA: Update documentation for pci_p2pdma_distance_many() Logan Gunthorpe
2019-07-22 23:08 ` [PATCH 14/14] PCI/P2PDMA: Introduce pci_p2pdma_[un]map_resource() Logan Gunthorpe
2019-07-23 16:28 ` Koenig, Christian
2019-07-23 16:58 ` Logan Gunthorpe
2019-07-24 6:32 ` Christoph Hellwig
2019-07-24 16:06 ` Logan Gunthorpe
2019-07-25 11:50 ` Christoph Hellwig
2019-07-25 16:00 ` Logan Gunthorpe [this message]
2019-07-23 16:30 ` [PATCH 00/14] PCI/P2PDMA: Support transactions that hit the host bridge Koenig, Christian
2019-07-23 16:58 ` Logan Gunthorpe
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