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Subject[PATCH 11/14] PCI/P2PDMA: dma_map P2PDMA map requests that traverse the host bridge
Any requests that traverse the host bridge will need to be mapped into
the IOMMU, so call dma_map_sg() inside pci_p2pdma_map_sg() when
appropriate.

Similarly, call dma_unmap_sg() inside pci_p2pdma_unmap_sg().

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
---
drivers/pci/p2pdma.c | 31 ++++++++++++++++++++++++++++++-
1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 5f43f92f9336..76f51678342c 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -830,8 +830,22 @@ int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
int nents, enum dma_data_direction dir, unsigned long attrs)
{
struct dev_pagemap *pgmap = sg_page(sg)->pgmap;
+ struct pci_dev *client;
+ int dist;
+
+ client = find_parent_pci_dev(dev);
+ if (WARN_ON_ONCE(!client))
+ return 0;

- return __pci_p2pdma_map_sg(pgmap, dev, sg, nents);
+ dist = upstream_bridge_distance(pgmap->pci_p2pdma_provider,
+ client, NULL);
+ if (WARN_ON_ONCE(dist & P2PDMA_NOT_SUPPORTED))
+ return 0;
+
+ if (dist & P2PDMA_THRU_HOST_BRIDGE)
+ return dma_map_sg_attrs(dev, sg, nents, dir, attrs);
+ else
+ return __pci_p2pdma_map_sg(pgmap, dev, sg, nents);
}
EXPORT_SYMBOL_GPL(pci_p2pdma_map_sg_attrs);

@@ -847,6 +861,21 @@ EXPORT_SYMBOL_GPL(pci_p2pdma_map_sg_attrs);
void pci_p2pdma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg,
int nents, enum dma_data_direction dir, unsigned long attrs)
{
+ struct dev_pagemap *pgmap = sg_page(sg)->pgmap;
+ struct pci_dev *client;
+ int dist;
+
+ client = find_parent_pci_dev(dev);
+ if (!client)
+ return;
+
+ dist = upstream_bridge_distance(pgmap->pci_p2pdma_provider,
+ client, NULL);
+ if (dist & P2PDMA_NOT_SUPPORTED)
+ return;
+
+ if (dist & P2PDMA_THRU_HOST_BRIDGE)
+ dma_unmap_sg_attrs(dev, sg, nents, dir, attrs);
}
EXPORT_SYMBOL_GPL(pci_p2pdma_unmap_sg_attrs);

--
2.20.1
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