ACPI / PCI: Make bus registration and unregistration symmetric

Since acpi_pci_slot_enumerate() and acpiphp_enumerate_slots() can get
the ACPI device handle they need from bus->bridge, it is not
necessary to pass that handle to them as an argument.

Drop the second argument of acpi_pci_slot_enumerate() and
acpiphp_enumerate_slots(), rework them to obtain the ACPI handle
from bus->bridge and make acpi_pci_add_bus() and
acpi_pci_remove_bus() entirely symmetrical.

Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>

4 files changed, 21 insertions, 25 deletions

diff --git a/drivers/acpi/pci_slot.c b/drivers/acpi/pci_slot.c
index 033d1179bdb5..d678a180ca2a 100644
--- a/drivers/acpi/pci_slot.c
+++ b/drivers/acpi/pci_slot.c
@@ -159,12 +159,16 @@ register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
         return AE_OK;
 }
 
-void acpi_pci_slot_enumerate(struct pci_bus *bus, acpi_handle handle)
+void acpi_pci_slot_enumerate(struct pci_bus *bus)
 {
-        mutex_lock(&slot_list_lock);
-        acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
-                            register_slot, NULL, bus, NULL);
-        mutex_unlock(&slot_list_lock);
+        acpi_handle handle = ACPI_HANDLE(bus->bridge);
+
+        if (handle) {
+                mutex_lock(&slot_list_lock);
+                acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
+                                    register_slot, NULL, bus, NULL);
+                mutex_unlock(&slot_list_lock);
+        }
 }
 
 void acpi_pci_slot_remove(struct pci_bus *bus)
diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 8bfad0dc29ab..a203ba529fef 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -1147,14 +1147,16 @@ static void handle_hotplug_event_func(acpi_handle handle, u32 type,
  * Create hotplug slots for the PCI bus.
  * It should always return 0 to avoid skipping following notifiers.
  */
-void acpiphp_enumerate_slots(struct pci_bus *bus, acpi_handle handle)
+void acpiphp_enumerate_slots(struct pci_bus *bus)
 {
+        acpi_handle handle;
         struct acpiphp_bridge *bridge;
 
         if (acpiphp_disabled)
                 return;
 
-        if (detect_ejectable_slots(handle) <= 0)
+        handle = ACPI_HANDLE(bus->bridge);
+        if (!handle || detect_ejectable_slots(handle) <= 0)
                 return;
 
         bridge = kzalloc(sizeof(struct acpiphp_bridge), GFP_KERNEL);
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index dbdc5f7e2b29..c78cc432edab 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -290,24 +290,16 @@ static struct pci_platform_pm_ops acpi_pci_platform_pm = {
 
 void acpi_pci_add_bus(struct pci_bus *bus)
 {
-        acpi_handle handle = NULL;
-
-        if (bus->bridge)
-                handle = ACPI_HANDLE(bus->bridge);
-        if (acpi_pci_disabled || handle == NULL)
+        if (acpi_pci_disabled || !bus->bridge)
                 return;
 
-        acpi_pci_slot_enumerate(bus, handle);
-        acpiphp_enumerate_slots(bus, handle);
+        acpi_pci_slot_enumerate(bus);
+        acpiphp_enumerate_slots(bus);
 }
 
 void acpi_pci_remove_bus(struct pci_bus *bus)
 {
-        /*
-         * bus->bridge->acpi_node.handle has already been reset to NULL
-         * when acpi_pci_remove_bus() is called, so don't check ACPI handle.
-         */
-        if (acpi_pci_disabled)
+        if (acpi_pci_disabled || !bus->bridge)
                 return;
 
         acpiphp_remove_slots(bus);
diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
index 170447977278..d006f0ca60f4 100644
--- a/include/linux/pci-acpi.h
+++ b/include/linux/pci-acpi.h
@@ -47,24 +47,22 @@ void acpi_pci_remove_bus(struct pci_bus *bus);
 
 #ifdef  CONFIG_ACPI_PCI_SLOT
 void acpi_pci_slot_init(void);
-void acpi_pci_slot_enumerate(struct pci_bus *bus, acpi_handle handle);
+void acpi_pci_slot_enumerate(struct pci_bus *bus);
 void acpi_pci_slot_remove(struct pci_bus *bus);
 #else
 static inline void acpi_pci_slot_init(void) { }
-static inline void acpi_pci_slot_enumerate(struct pci_bus *bus,
-                                           acpi_handle handle) { }
+static inline void acpi_pci_slot_enumerate(struct pci_bus *bus) { }
 static inline void acpi_pci_slot_remove(struct pci_bus *bus) { }
 #endif
 
 #ifdef  CONFIG_HOTPLUG_PCI_ACPI
 void acpiphp_init(void);
-void acpiphp_enumerate_slots(struct pci_bus *bus, acpi_handle handle);
+void acpiphp_enumerate_slots(struct pci_bus *bus);
 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_enumerate_slots(struct pci_bus *bus) { }
 static inline void acpiphp_remove_slots(struct pci_bus *bus) { }
 static inline void acpiphp_check_host_bridge(acpi_handle handle) { }
 #endif