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

Logan Gunthorpe
2019-07-22T23:09:13Z

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 <logang@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