[PATCH v2 12/14] PCI/P2PDMA: dma_map P2PDMA map requests that traverse the host bridge

Logan Gunthorpe
2019-07-30T16:37:02Z

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 | 40 +++++++++++++++++++++++++++++++++++++++-
1 file changed, 39 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 010aa8742bec..b86a1c0c11a0 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -812,6 +812,16 @@ void pci_p2pmem_publish(struct pci_dev *pdev, bool publish)
}
EXPORT_SYMBOL_GPL(pci_p2pmem_publish);

+static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct pci_dev *provider,
+ struct pci_dev *client)
+{
+ if (!provider->p2pdma)
+ return PCI_P2PDMA_MAP_NOT_SUPPORTED;
+
+ return xa_to_value(xa_load(&provider->p2pdma->map_types,
+ map_types_idx(client)));
+}
+
static int __pci_p2pdma_map_sg(struct pci_p2pdma_pagemap *p2p_pgmap,
struct device *dev, struct scatterlist *sg, int nents)
{
@@ -857,8 +867,22 @@ int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
{
struct pci_p2pdma_pagemap *p2p_pgmap =
to_p2p_pgmap(sg_page(sg)->pgmap);
+ struct pci_dev *client;

- return __pci_p2pdma_map_sg(p2p_pgmap, dev, sg, nents);
+ if (WARN_ON_ONCE(!dev_is_pci(dev)))
+ return 0;
+
+ client = to_pci_dev(dev);
+
+ switch (pci_p2pdma_map_type(p2p_pgmap->provider, client)) {
+ case PCI_P2PDMA_MAP_THRU_IOMMU:
+ return dma_map_sg_attrs(dev, sg, nents, dir, attrs);
+ case PCI_P2PDMA_MAP_BUS_ADDR:
+ return __pci_p2pdma_map_sg(p2p_pgmap, dev, sg, nents);
+ default:
+ WARN_ON_ONCE(1);
+ return 0;
+ }
}
EXPORT_SYMBOL_GPL(pci_p2pdma_map_sg_attrs);

@@ -874,6 +898,20 @@ 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 pci_p2pdma_pagemap *p2p_pgmap =
+ to_p2p_pgmap(sg_page(sg)->pgmap);
+ enum pci_p2pdma_map_type map_type;
+ struct pci_dev *client;
+
+ if (WARN_ON_ONCE(!dev_is_pci(dev)))
+ return;
+
+ client = to_pci_dev(dev);
+
+ map_type = pci_p2pdma_map_type(p2p_pgmap->provider, client);
+
+ if (map_type == PCI_P2PDMA_MAP_THRU_IOMMU)
+ dma_unmap_sg_attrs(dev, sg, nents, dir, attrs);
}
EXPORT_SYMBOL_GPL(pci_p2pdma_unmap_sg_attrs);

--
2.20.1