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From: Ira Weiny <ira.weiny@intel.com>
To: Logan Gunthorpe <logang@deltatee.com>
Cc: linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
	linux-block@vger.kernel.org, linux-pci@vger.kernel.org,
	linux-mm@kvack.org, iommu@lists.linux-foundation.org,
	"Stephen Bates" <sbates@raithlin.com>,
	"Christoph Hellwig" <hch@lst.de>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Jason Gunthorpe" <jgg@ziepe.ca>,
	"Christian König" <christian.koenig@amd.com>,
	"Ira Weiny" <iweiny@intel.com>,
	"John Hubbard" <jhubbard@nvidia.com>,
	"Don Dutile" <ddutile@redhat.com>,
	"Matthew Wilcox" <willy@infradead.org>,
	"Daniel Vetter" <daniel.vetter@ffwll.ch>,
	"Jakowski Andrzej" <andrzej.jakowski@intel.com>,
	"Minturn Dave B" <dave.b.minturn@intel.com>,
	"Jason Ekstrand" <jason@jlekstrand.net>,
	"Dave Hansen" <dave.hansen@linux.intel.com>,
	"Xiong Jianxin" <jianxin.xiong@intel.com>
Subject: Re: [RFC PATCH v2 04/11] PCI/P2PDMA: Introduce pci_p2pdma_should_map_bus() and pci_p2pdma_bus_offset()
Date: Fri, 12 Mar 2021 18:32:20 -0800	[thread overview]
Message-ID: <20210313023220.GB3402637@iweiny-DESK2.sc.intel.com> (raw)
In-Reply-To: <20210311233142.7900-5-logang@deltatee.com>

On Thu, Mar 11, 2021 at 04:31:34PM -0700, Logan Gunthorpe wrote:
> Introduce pci_p2pdma_should_map_bus() which is meant to be called by
            ^^^^^^^^^^^^^^^^^^^^^^^^^
	    pci_p2pdma_dma_map_type() ???

FWIW I find this name confusing with pci_p2pdma_map_type() and looking at the
implementation I'm not clear why pci_p2pdma_dma_map_type() needs to exist?

Ira

[snip]

> +
> +/**
> + * pci_p2pdma_dma_map_type - determine if a DMA mapping should use the
> + *	bus address, be mapped normally or fail
> + * @dev: device doing the DMA request
> + * @pgmap: dev_pagemap structure for the mapping
> + *
> + * Returns:
> + *    1 - if the page should be mapped with a bus address,
> + *    0 - if the page should be mapped normally through an IOMMU mapping or
> + *        physical address; or
> + *   -1 - if the device should not map the pages and an error should be
> + *        returned
> + */
> +int pci_p2pdma_dma_map_type(struct device *dev, struct dev_pagemap *pgmap)
> +{
> +	struct pci_p2pdma_pagemap *p2p_pgmap = to_p2p_pgmap(pgmap);
> +	struct pci_dev *client;
> +
> +	if (!dev_is_pci(dev))
> +		return -1;
> +
> +	client = to_pci_dev(dev);
> +
> +	switch (pci_p2pdma_map_type(p2p_pgmap->provider, client)) {
> +	case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE:
> +		return 0;
> +	case PCI_P2PDMA_MAP_BUS_ADDR:
> +		return 1;
> +	default:
> +		return -1;
> +	}
> +}
> +EXPORT_SYMBOL_GPL(pci_p2pdma_dma_map_type);

I guess the main point here is to export this to the DMA layer?

Ira

  parent reply	other threads:[~2021-03-13  2:33 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-11 23:31 [RFC PATCH v2 00/11] Add support to dma_map_sg for P2PDMA Logan Gunthorpe
2021-03-11 23:31 ` [RFC PATCH v2 01/11] PCI/P2PDMA: Pass gfp_mask flags to upstream_bridge_distance_warn() Logan Gunthorpe
2021-03-12 20:39   ` Bjorn Helgaas
2021-03-12 20:53     ` Logan Gunthorpe
2021-03-11 23:31 ` [RFC PATCH v2 02/11] PCI/P2PDMA: Avoid pci_get_slot() which sleeps Logan Gunthorpe
2021-03-12 20:57   ` Bjorn Helgaas
2021-03-12 21:37     ` Logan Gunthorpe
2021-03-11 23:31 ` [RFC PATCH v2 03/11] PCI/P2PDMA: Attempt to set map_type if it has not been set Logan Gunthorpe
2021-03-11 23:31 ` [RFC PATCH v2 04/11] PCI/P2PDMA: Introduce pci_p2pdma_should_map_bus() and pci_p2pdma_bus_offset() Logan Gunthorpe
2021-03-13  1:38   ` Ira Weiny
2021-03-15 16:27     ` Logan Gunthorpe
2021-03-24 17:21       ` Jason Gunthorpe
2021-03-24 18:34         ` Christian König
2021-03-13  2:32   ` Ira Weiny [this message]
2021-03-15 16:30     ` Logan Gunthorpe
2021-03-16  8:14   ` Christoph Hellwig
2021-03-11 23:31 ` [RFC PATCH v2 05/11] lib/scatterlist: Add flag for indicating P2PDMA segments in an SGL Logan Gunthorpe
2021-03-11 23:31 ` [RFC PATCH v2 06/11] dma-direct: Support PCI P2PDMA pages in dma-direct map_sg Logan Gunthorpe
2021-03-12 15:52   ` Robin Murphy
2021-03-12 16:24     ` Logan Gunthorpe
2021-03-12 18:11       ` Robin Murphy
2021-03-12 18:27         ` Logan Gunthorpe
2021-03-16  7:58           ` Christoph Hellwig
2021-03-16 15:54             ` Logan Gunthorpe
2021-03-16  7:56         ` Christoph Hellwig
2021-03-16  8:11   ` Christoph Hellwig
2021-03-11 23:31 ` [RFC PATCH v2 07/11] dma-mapping: Add flags to dma_map_ops to indicate PCI P2PDMA support Logan Gunthorpe
2021-03-13  2:36   ` Ira Weiny
2021-03-15 16:33     ` Logan Gunthorpe
2021-03-16  8:00       ` Christoph Hellwig
2021-03-16  8:15   ` Christoph Hellwig
2021-03-11 23:31 ` [RFC PATCH v2 08/11] iommu/dma: Support PCI P2PDMA pages in dma-iommu map_sg Logan Gunthorpe
2021-03-12 15:52   ` Robin Murphy
2021-03-12 17:03     ` Logan Gunthorpe
2021-03-12 19:47       ` Robin Murphy
2021-03-12 20:06         ` Logan Gunthorpe
2021-03-11 23:31 ` [RFC PATCH v2 09/11] block: Add BLK_STS_P2PDMA Logan Gunthorpe
2021-03-16  8:00   ` Christoph Hellwig
2021-03-16 16:02     ` Logan Gunthorpe
2021-03-11 23:31 ` [RFC PATCH v2 10/11] nvme-pci: Check DMA ops when indicating support for PCI P2PDMA Logan Gunthorpe
2021-03-11 23:31 ` [RFC PATCH v2 11/11] nvme-pci: Convert to using dma_map_sg for p2pdma pages Logan Gunthorpe
2021-03-11 23:59   ` Jason Gunthorpe
2021-03-12  1:37     ` Logan Gunthorpe
2021-03-12 15:51 ` [RFC PATCH v2 00/11] Add support to dma_map_sg for P2PDMA Robin Murphy
2021-03-12 16:18   ` Logan Gunthorpe
2021-03-12 17:46     ` Robin Murphy
2021-03-12 18:24       ` Logan Gunthorpe

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