ACPI: introduce notifier change to avoid duplicates

The battery driver already registers notification handler.
To avoid registering notification handler again,
introduce a notifier chain in global system notifier handler
and use it in dock driver.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

3 files changed, 42 insertions, 22 deletions

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index ccae305ee55d..0dc44945725e 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -496,6 +496,19 @@ static int acpi_bus_check_scope(struct acpi_device *device)
         return 0;
 }
 
+static BLOCKING_NOTIFIER_HEAD(acpi_bus_notify_list);
+int register_acpi_bus_notifier(struct notifier_block *nb)
+{
+        return blocking_notifier_chain_register(&acpi_bus_notify_list, nb);
+}
+EXPORT_SYMBOL_GPL(register_acpi_bus_notifier);
+
+void unregister_acpi_bus_notifier(struct notifier_block *nb)
+{
+        blocking_notifier_chain_unregister(&acpi_bus_notify_list, nb);
+}
+EXPORT_SYMBOL_GPL(unregister_acpi_bus_notifier);
+
 /**
  * acpi_bus_notify
  * ---------------
@@ -506,6 +519,8 @@ static void acpi_bus_notify(acpi_handle handle, u32 type, void *data)
         int result = 0;
         struct acpi_device *device = NULL;
 
+        blocking_notifier_call_chain(&acpi_bus_notify_list,
+                type, (void *)handle);
 
         if (acpi_bus_get_device(handle, &device))
                 return;
diff --git a/drivers/acpi/dock.c b/drivers/acpi/dock.c
index 799a0fdbb62d..2563bc62987d 100644
--- a/drivers/acpi/dock.c
+++ b/drivers/acpi/dock.c
@@ -748,6 +748,28 @@ static void dock_notify(acpi_handle handle, u32 event, void *data)
         }
 }
 
+static int acpi_dock_notifier_call(struct notifier_block *this,
+        unsigned long event, void *data)
+{
+        struct dock_station *dock_station;
+        acpi_handle handle = (acpi_handle)data;
+
+        if (event != ACPI_NOTIFY_BUS_CHECK && event != ACPI_NOTIFY_DEVICE_CHECK
+           && event != ACPI_NOTIFY_EJECT_REQUEST)
+                return 0;
+        list_for_each_entry(dock_station, &dock_stations, sibiling) {
+                if (dock_station->handle == handle) {
+                        dock_notify(handle, event, dock_station);
+                        return 0 ;
+                }
+        }
+        return 0;
+}
+
+static struct notifier_block dock_acpi_notifier = {
+        .notifier_call = acpi_dock_notifier_call,
+};
+
 /**
  * find_dock_devices - find devices on the dock station
  * @handle: the handle of the device we are examining
@@ -861,7 +883,6 @@ static DEVICE_ATTR(uid, S_IRUGO, show_dock_uid, NULL);
 static int dock_add(acpi_handle handle)
 {
         int ret;
-        acpi_status status;
         struct dock_dependent_device *dd;
         struct dock_station *dock_station;
         struct platform_device *dock_device;
@@ -956,23 +977,10 @@ static int dock_add(acpi_handle handle)
         }
         add_dock_dependent_device(dock_station, dd);
 
-        /* register for dock events */
-        status = acpi_install_notify_handler(dock_station->handle,
-                                             ACPI_SYSTEM_NOTIFY,
-                                             dock_notify, dock_station);
-
-        if (ACPI_FAILURE(status)) {
-                printk(KERN_ERR PREFIX "Error installing notify handler\n");
-                ret = -ENODEV;
-                goto dock_add_err;
-        }
-
         dock_station_count++;
         list_add(&dock_station->sibiling, &dock_stations);
         return 0;
 
-dock_add_err:
-        kfree(dd);
 dock_add_err_unregister:
         device_remove_file(&dock_device->dev, &dev_attr_docked);
         device_remove_file(&dock_device->dev, &dev_attr_undock);
@@ -990,7 +998,6 @@ dock_add_err_unregister:
 static int dock_remove(struct dock_station *dock_station)
 {
         struct dock_dependent_device *dd, *tmp;
-        acpi_status status;
         struct platform_device *dock_device = dock_station->dock_device;
 
         if (!dock_station_count)
@@ -1001,13 +1008,6 @@ static int dock_remove(struct dock_station *dock_station)
                                  list)
             kfree(dd);
 
-        /* remove dock notify handler */
-        status = acpi_remove_notify_handler(dock_station->handle,
-                                            ACPI_SYSTEM_NOTIFY,
-                                            dock_notify);
-        if (ACPI_FAILURE(status))
-                printk(KERN_ERR "Error removing notify handler\n");
-
         /* cleanup sysfs */
         device_remove_file(&dock_device->dev, &dev_attr_docked);
         device_remove_file(&dock_device->dev, &dev_attr_undock);
@@ -1069,6 +1069,7 @@ static int __init dock_init(void)
                 return 0;
         }
 
+        register_acpi_bus_notifier(&dock_acpi_notifier);
         printk(KERN_INFO PREFIX "%s: %d docks/bays found\n",
                 ACPI_DOCK_DRIVER_DESCRIPTION, dock_station_count);
         return 0;
@@ -1078,6 +1079,7 @@ static void __exit dock_exit(void)
 {
         struct dock_station *dock_station;
 
+        unregister_acpi_bus_notifier(&dock_acpi_notifier);
         list_for_each_entry(dock_station, &dock_stations, sibiling)
                 dock_remove(dock_station);
 }
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index a5ac0bc7f52e..f74f882609f8 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -327,6 +327,9 @@ int acpi_bus_get_private_data(acpi_handle, void **);
 extern int acpi_notifier_call_chain(struct acpi_device *, u32, u32);
 extern int register_acpi_notifier(struct notifier_block *);
 extern int unregister_acpi_notifier(struct notifier_block *);
+
+extern int register_acpi_bus_notifier(struct notifier_block *nb);
+extern void unregister_acpi_bus_notifier(struct notifier_block *nb);
 /*
  * External Functions
  */