PCI/P2PDMA: Apply host bridge whitelist for ACS

When a P2PDMA transfer is rejected due to ACS being set, we can also check
the whitelist and allow the transactions.

Do this by pushing the whitelist check into the upstream_bridge_distance()
function.

Link: https://lore.kernel.org/r/20190730163545.4915-6-logang@deltatee.com
Link: https://lore.kernel.org/r/20190812173048.9186-6-logang@deltatee.com
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 600ba6a7aa116e8610b749a2fe905c9586556803..f7f7e5862bab73b483e3261cbdde9e9e793aef06 100644 (file)
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -339,15 +339,7 @@ __upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client,
        if (dist)
                *dist = dist_a + dist_b;
 
-       /*
-        * Allow the connection if both devices are on a whitelisted root
-        * complex, but add an arbitrary large value to the distance.
-        */
-       if (root_complex_whitelist(provider) &&
-           root_complex_whitelist(client))
-               return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE;
-
-       return PCI_P2PDMA_MAP_NOT_SUPPORTED;
+       return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE;
 
 check_b_path_acs:
        bb = b;
@@ -371,7 +363,7 @@ check_b_path_acs:
                if (acs_redirects)
                        *acs_redirects = true;
 
-               return PCI_P2PDMA_MAP_NOT_SUPPORTED;
+               return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE;
        }
 
        return PCI_P2PDMA_MAP_BUS_ADDR;
@@ -420,8 +412,18 @@ 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)
 {
-       return __upstream_bridge_distance(provider, client, dist,
-                                         acs_redirects, acs_list);
+       enum pci_p2pdma_map_type map_type;
+
+       map_type = __upstream_bridge_distance(provider, client, dist,
+                                             acs_redirects, acs_list);
+
+       if (map_type == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE) {
+               if (!root_complex_whitelist(provider) ||
+                   !root_complex_whitelist(client))
+                       return PCI_P2PDMA_MAP_NOT_SUPPORTED;
+       }
+
+       return map_type;
 }
 
 static enum pci_p2pdma_map_type