From: Logan Gunthorpe <logang@deltatee.com>
Date: Mon, 12 Aug 2019 11:30:40 -0600
Subject: PCI/P2PDMA: Factor out host_bridge_whitelist()
Patch-mainline: v5.4-rc1
Git-commit: 2c84d818aee976390c055a417045a85c23d39662
References: jsc#SLE-8449

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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/pci/p2pdma.c |   31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -269,19 +269,11 @@ static void seq_buf_print_bus_devfn(stru
 	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(struc
 	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
 					      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;
 	}