1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 803d9ddd6e75..a33794d9e0dc 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -38,6 +38,8 @@
  *  - The one in acpiphp_bridge has its refcount elevated by pci_get_slot()
  *    when the bridge is scanned and it loses a refcount when the bridge
  *    is removed.
+ *  - When a P2P bridge is present, we elevate the refcount on the subordinate
+ *    bus. It loses the refcount when the the driver unloads.
  */
 
 #include <linux/init.h>
@@ -440,6 +442,12 @@ static void add_p2p_bridge(acpi_handle *handle, struct pci_dev *pci_dev)
                 goto err;
         }
 
+        /*
+         * Grab a ref to the subordinate PCI bus in case the bus is
+         * removed via PCI core logical hotplug. The ref pins the bus
+         * (which we access during module unload).
+         */
+        get_device(&bridge->pci_bus->dev);
         spin_lock_init(&bridge->res_lock);
 
         init_bridge_misc(bridge);
@@ -619,6 +627,12 @@ static void cleanup_bridge(struct acpiphp_bridge *bridge)
                 slot = next;
         }
 
+        /*
+         * Only P2P bridges have a pci_dev
+         */
+        if (bridge->pci_dev)
+                put_device(&bridge->pci_bus->dev);
+
         pci_dev_put(bridge->pci_dev);
         list_del(&bridge->list);
         kfree(bridge);