[PATCH 03/14] PCI/P2PDMA: Apply host bridge white list for ACS

[Logan Gunthorpe]

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

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

Signed-off-by: Logan Gunthorpe <log...@deltatee.com>
---
 drivers/pci/p2pdma.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 289d03a31e7d..d5034e28d1e1 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -324,15 +324,7 @@ static int __upstream_bridge_distance(struct pci_dev 
*provider,
                dist_a++;
        }
 
-       /*
-        * 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 (dist_a + dist_b) | P2PDMA_THRU_HOST_BRIDGE;
-
-       return (dist_a + dist_b) | P2PDMA_NOT_SUPPORTED;
+       return (dist_a + dist_b) | P2PDMA_THRU_HOST_BRIDGE;
 
 check_b_path_acs:
        bb = b;
@@ -350,7 +342,8 @@ static int __upstream_bridge_distance(struct pci_dev 
*provider,
        }
 
        if (acs_cnt)
-               return P2PDMA_NOT_SUPPORTED | P2PDMA_ACS_FORCES_UPSTREAM;
+               return (dist_a + dist_b) | P2PDMA_ACS_FORCES_UPSTREAM |
+                       P2PDMA_THRU_HOST_BRIDGE;
 
        return dist_a + dist_b;
 }
@@ -397,7 +390,17 @@ static int upstream_bridge_distance(struct pci_dev 
*provider,
                                    struct pci_dev *client,
                                    struct seq_buf *acs_list)
 {
-       return __upstream_bridge_distance(provider, client, acs_list);
+       int dist;
+
+       dist = __upstream_bridge_distance(provider, client, acs_list);
+
+       if (!(dist & P2PDMA_THRU_HOST_BRIDGE))
+               return dist;
+
+       if (root_complex_whitelist(provider) && root_complex_whitelist(client))
+               return dist;
+
+       return dist | P2PDMA_NOT_SUPPORTED;
 }
 
 static int upstream_bridge_distance_warn(struct pci_dev *provider,
-- 
2.20.1