1 files changed, 18 insertions, 12 deletions

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index f4599261cfc3..65fa3444367a 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -21,7 +21,7 @@
 #include <linux/suspend.h>
 #include <linux/types.h>
 
-#include <asm/unaligned.h>
+#include <linux/unaligned.h>
 
 #include <linux/acpi.h>
 #include <linux/power_supply.h>
@@ -703,28 +703,35 @@ static LIST_HEAD(acpi_battery_list);
 static LIST_HEAD(battery_hook_list);
 static DEFINE_MUTEX(hook_mutex);
 
-static void __battery_hook_unregister(struct acpi_battery_hook *hook, int lock)
+static void battery_hook_unregister_unlocked(struct acpi_battery_hook *hook)
 {
 	struct acpi_battery *battery;
+
 	/*
 	 * In order to remove a hook, we first need to
 	 * de-register all the batteries that are registered.
 	 */
-	if (lock)
-		mutex_lock(&hook_mutex);
 	list_for_each_entry(battery, &acpi_battery_list, list) {
 		if (!hook->remove_battery(battery->bat, hook))
 			power_supply_changed(battery->bat);
 	}
-	list_del(&hook->list);
-	if (lock)
-		mutex_unlock(&hook_mutex);
+	list_del_init(&hook->list);
+
 	pr_info("extension unregistered: %s\n", hook->name);
 }
 
 void battery_hook_unregister(struct acpi_battery_hook *hook)
 {
-	__battery_hook_unregister(hook, 1);
+	mutex_lock(&hook_mutex);
+	/*
+	 * Ignore already unregistered battery hooks. This might happen
+	 * if a battery hook was previously unloaded due to an error when
+	 * adding a new battery.
+	 */
+	if (!list_empty(&hook->list))
+		battery_hook_unregister_unlocked(hook);
+
+	mutex_unlock(&hook_mutex);
 }
 EXPORT_SYMBOL_GPL(battery_hook_unregister);
 
@@ -733,7 +740,6 @@ void battery_hook_register(struct acpi_battery_hook *hook)
 	struct acpi_battery *battery;
 
 	mutex_lock(&hook_mutex);
-	INIT_LIST_HEAD(&hook->list);
 	list_add(&hook->list, &battery_hook_list);
 	/*
 	 * Now that the driver is registered, we need
@@ -750,7 +756,7 @@ void battery_hook_register(struct acpi_battery_hook *hook)
 			 * hooks.
 			 */
 			pr_err("extension failed to load: %s", hook->name);
-			__battery_hook_unregister(hook, 0);
+			battery_hook_unregister_unlocked(hook);
 			goto end;
 		}
 
@@ -804,7 +810,7 @@ static void battery_hook_add_battery(struct acpi_battery *battery)
 			 */
 			pr_err("error in extension, unloading: %s",
 					hook_node->name);
-			__battery_hook_unregister(hook_node, 0);
+			battery_hook_unregister_unlocked(hook_node);
 		}
 	}
 	mutex_unlock(&hook_mutex);
@@ -837,7 +843,7 @@ static void __exit battery_hook_exit(void)
 	 * need to remove the hooks.
 	 */
 	list_for_each_entry_safe(hook, ptr, &battery_hook_list, list) {
-		__battery_hook_unregister(hook, 1);
+		battery_hook_unregister(hook);
 	}
 	mutex_destroy(&hook_mutex);
 }