[PATCH v3 04/14] PCI/P2PDMA: Factor out __upstream_bridge_distance()

Logan Gunthorpe
2019-08-12T17:30:58Z

This is a prep patch to create a second level helper. There are no
functional changes.

The root complex whitelist code will be moved into this function in a
subsequent patch.

Link: https://lore.kernel.org/r/20190730163545.4915-5-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>
---
drivers/pci/p2pdma.c | 88 ++++++++++++++++++++++++--------------------
1 file changed, 48 insertions(+), 40 deletions(-)

diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 8f0688201aec..600ba6a7aa11 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -296,47 +296,8 @@ static bool root_complex_whitelist(struct pci_dev *dev)
return false;
}

-/*
- * Find the distance through the nearest common upstream bridge between
- * two PCI devices.
- *
- * If the two devices are the same device then 0 will be returned.
- *
- * If there are two virtual functions of the same device behind the same
- * bridge port then 2 will be returned (one step down to the PCIe switch,
- * then one step back to the same device).
- *
- * In the case where two devices are connected to the same PCIe switch, the
- * value 4 will be returned. This corresponds to the following PCI tree:
- *
- * -+ Root Port
- * \+ Switch Upstream Port
- * +-+ Switch Downstream Port
- * + \- Device A
- * \-+ Switch Downstream Port
- * \- Device B
- *
- * The distance is 4 because we traverse from Device A through the downstream
- * port of the switch, to the common upstream port, back up to the second
- * downstream port and then to Device B.
- *
- * Any two devices that cannot communicate using p2pdma will return
- * PCI_P2PDMA_MAP_NOT_SUPPORTED.
- *
- * Any two devices that have a data path that goes through the host bridge
- * will consult a whitelist. If the host bridges are on the whitelist,
- * this function will return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE.
- *
- * If either bridge is not on the whitelist this function returns
- * PCI_P2PDMA_MAP_NOT_SUPPORTED.
- *
- * If a bridge which has any ACS redirection bits set is in the path,
- * acs_redirects will be set to true. In this case, a list of all infringing
- * bridge addresses will be populated in acs_list (assuming it's non-null)
- * for printk purposes.
- */
static enum pci_p2pdma_map_type
-upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client,
+__upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client,
int *dist, bool *acs_redirects, struct seq_buf *acs_list)
{
struct pci_dev *a = provider, *b = client, *bb;
@@ -416,6 +377,53 @@ upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client,
return PCI_P2PDMA_MAP_BUS_ADDR;
}

+/*
+ * Find the distance through the nearest common upstream bridge between
+ * two PCI devices.
+ *
+ * If the two devices are the same device then 0 will be returned.
+ *
+ * If there are two virtual functions of the same device behind the same
+ * bridge port then 2 will be returned (one step down to the PCIe switch,
+ * then one step back to the same device).
+ *
+ * In the case where two devices are connected to the same PCIe switch, the
+ * value 4 will be returned. This corresponds to the following PCI tree:
+ *
+ * -+ Root Port
+ * \+ Switch Upstream Port
+ * +-+ Switch Downstream Port
+ * + \- Device A
+ * \-+ Switch Downstream Port
+ * \- Device B
+ *
+ * The distance is 4 because we traverse from Device A through the downstream
+ * port of the switch, to the common upstream port, back up to the second
+ * downstream port and then to Device B.
+ *
+ * Any two devices that cannot communicate using p2pdma will return
+ * PCI_P2PDMA_MAP_NOT_SUPPORTED.
+ *
+ * Any two devices that have a data path that goes through the host bridge
+ * will consult a whitelist. If the host bridges are on the whitelist,
+ * this function will return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE.
+ *
+ * If either bridge is not on the whitelist this function returns
+ * PCI_P2PDMA_MAP_NOT_SUPPORTED.
+ *
+ * If a bridge which has any ACS redirection bits set is in the path,
+ * acs_redirects will be set to true. In this case, a list of all infringing
+ * bridge addresses will be populated in acs_list (assuming it's non-null)
+ * for printk purposes.
+ */
+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);
+}
+
static enum pci_p2pdma_map_type
upstream_bridge_distance_warn(struct pci_dev *provider, struct pci_dev *client,
int *dist)
--
2.20.1