PCI: acpiphp: Re-enumerate devices when host bridge receives Bus Check

When a PCI host bridge device receives a Bus Check notification, we
must re-enumerate starting with the bridge to discover changes (devices
that have been added or removed).

Prior to 668192b678 ("PCI: acpiphp: Move host bridge hotplug to
pci_root.c"), this happened in _handle_hotplug_event_bridge().  After that
commit, _handle_hotplug_event_bridge() is not installed for host bridges,
and the host bridge notify handler, _handle_hotplug_event_root() did not
re-enumerate.

This patch adds re-enumeration to _handle_hotplug_event_root().

This fixes cases where we don't notice the addition or removal of
PCI devices, e.g., the PCI-to-USB ExpressCard in the bugzilla below.

[bhelgaas: changelog, references]
Reference: https://lkml.kernel.org/r/CAAh6nkmbKR3HTqm5ommevsBwhL_u0N8Rk7Wsms_LfP=nBgKNew@mail.gmail.com
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=57961
Reported-by: Gavin Guo <tuffkidtt@gmail.com>
Tested-by: Gavin Guo <tuffkidtt@gmail.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jiang Liu <jiang.liu@huawei.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
CC: stable@vger.kernel.org	# v3.9+

3 files changed, 19 insertions, 1 deletions

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 1dd6f6c85874..e427dc516c76 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -641,7 +641,9 @@ static void _handle_hotplug_event_root(struct work_struct *work)
                 /* bus enumerate */
                 printk(KERN_DEBUG "%s: Bus check notify on %s\n", __func__,
                                  (char *)buffer.pointer);
-                if (!root)
+                if (root)
+                        acpiphp_check_host_bridge(handle);
+                else
                         handle_root_bridge_insertion(handle);
 
                 break;
diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 96fed19c6d90..716aa93fff76 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -950,6 +950,20 @@ check_sub_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
         return AE_OK ;
 }
 
+void acpiphp_check_host_bridge(acpi_handle handle)
+{
+        struct acpiphp_bridge *bridge;
+
+        bridge = acpiphp_handle_to_bridge(handle);
+        if (bridge) {
+                acpiphp_check_bridge(bridge);
+                put_bridge(bridge);
+        }
+
+        acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,
+                ACPI_UINT32_MAX, check_sub_bridges, NULL, NULL, NULL);
+}
+
 static void _handle_hotplug_event_bridge(struct work_struct *work)
 {
         struct acpiphp_bridge *bridge;
diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
index 81b31613eb25..170447977278 100644
--- a/include/linux/pci-acpi.h
+++ b/include/linux/pci-acpi.h
@@ -60,11 +60,13 @@ static inline void acpi_pci_slot_remove(struct pci_bus *bus) { }
 void acpiphp_init(void);
 void acpiphp_enumerate_slots(struct pci_bus *bus, acpi_handle handle);
 void acpiphp_remove_slots(struct pci_bus *bus);
+void acpiphp_check_host_bridge(acpi_handle handle);
 #else
 static inline void acpiphp_init(void) { }
 static inline void acpiphp_enumerate_slots(struct pci_bus *bus,
                                            acpi_handle handle) { }
 static inline void acpiphp_remove_slots(struct pci_bus *bus) { }
+static inline void acpiphp_check_host_bridge(acpi_handle handle) { }
 #endif
 
 #else   /* CONFIG_ACPI */