PCI/P2PDMA: Factor out host_bridge_whitelist()

Push both PCI devices into the whitelist checking function seeing some
hardware will require us ensuring they are on the same host bridge.

At the same time we rename root_complex_whitelist() to
host_bridge_whitelist() to match the terminology used in the code.

Link: https://lore.kernel.org/r/20190730163545.4915-7-logang@deltatee.com
Link: https://lore.kernel.org/r/20190812173048.9186-7-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 f7f7e5862bab73b483e3261cbdde9e9e793aef06..4b9f0903b3400f321583eaa631a56c8a9c37e03c 100644 (file)
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -269,19 +269,11 @@ static void seq_buf_print_bus_devfn(struct seq_buf *buf, struct pci_dev *pdev)
        seq_buf_printf(buf, "%s;", pci_name(pdev));
 }
 
-/*
- * If we can't find a common upstream bridge take a look at the root
- * complex and compare it to a whitelist of known good hardware.
- */
-static bool root_complex_whitelist(struct pci_dev *dev)
+static bool __host_bridge_whitelist(struct pci_host_bridge *host)
 {
-       struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
        struct pci_dev *root = pci_get_slot(host->bus, PCI_DEVFN(0, 0));
        unsigned short vendor, device;
 
-       if (iommu_present(dev->dev.bus))
-               return false;
-
        if (!root)
                return false;
 
@@ -296,6 +288,24 @@ static bool root_complex_whitelist(struct pci_dev *dev)
        return false;
 }
 
+/*
+ * If we can't find a common upstream bridge take a look at the root
+ * complex and compare it to a whitelist of known good hardware.
+ */
+static bool host_bridge_whitelist(struct pci_dev *a, struct pci_dev *b)
+{
+       struct pci_host_bridge *host_a = pci_find_host_bridge(a->bus);
+       struct pci_host_bridge *host_b = pci_find_host_bridge(b->bus);
+
+       if (iommu_present(a->dev.bus) || iommu_present(b->dev.bus))
+               return false;
+
+       if (__host_bridge_whitelist(host_a) && __host_bridge_whitelist(host_b))
+               return true;
+
+       return false;
+}
+
 static enum pci_p2pdma_map_type
 __upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client,
                int *dist, bool *acs_redirects, struct seq_buf *acs_list)
@@ -418,8 +428,7 @@ upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client,
                                              acs_redirects, acs_list);
 
        if (map_type == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE) {
-               if (!root_complex_whitelist(provider) ||
-                   !root_complex_whitelist(client))
+               if (!host_bridge_whitelist(provider, client))
                        return PCI_P2PDMA_MAP_NOT_SUPPORTED;
        }