PCI/P2PDMA: dma_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().

Link: https://lore.kernel.org/r/20190730163545.4915-13-logang@deltatee.com
Link: https://lore.kernel.org/r/20190812173048.9186-13-logang@deltatee.com
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index db8224f..bca1ffc 100644 (file)
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -807,6 +807,16 @@ 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)
 {
@@ -852,8 +862,22 @@ 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_HOST_BRIDGE:
+               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);
 
@@ -869,6 +893,20 @@ 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_HOST_BRIDGE)
+               dma_unmap_sg_attrs(dev, sg, nents, dir, attrs);
 }
 EXPORT_SYMBOL_GPL(pci_p2pdma_unmap_sg_attrs);