diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index d7b499f..8165103 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -113,7 +113,7 @@
 	acpi_string oem_info;
 };
 
-enum acpi_battery_files {
+enum acpi_battery_files{
 	ACPI_BATTERY_INFO = 0,
 	ACPI_BATTERY_STATE,
 	ACPI_BATTERY_ALARM,
@@ -129,14 +129,13 @@
 };
 
 struct acpi_battery {
+	struct mutex mutex;
 	struct acpi_device *device;
 	struct acpi_battery_flags flags;
 	struct acpi_buffer bif_data;
 	struct acpi_buffer bst_data;
-	struct mutex lock;
 	unsigned long alarm;
 	unsigned long update_time[ACPI_BATTERY_NUMFILES];
-
 };
 
 inline int acpi_battery_present(struct acpi_battery *battery)
@@ -236,10 +235,10 @@
 		return 0;
 
 	/* Evaluate _BIF */
-	mutex_lock(&battery->lock);
-	status = acpi_evaluate_object(acpi_battery_handle(battery), "_BIF",
-				      NULL, &buffer);
-	mutex_unlock(&battery->lock);
+
+	status =
+	    acpi_evaluate_object(acpi_battery_handle(battery), "_BIF", NULL,
+				 &buffer);
 	if (ACPI_FAILURE(status)) {
 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _BIF"));
 		return -ENODEV;
@@ -286,10 +285,10 @@
 		return 0;
 
 	/* Evaluate _BST */
-	mutex_lock(&battery->lock);
-	status = acpi_evaluate_object(acpi_battery_handle(battery), "_BST",
-				      NULL, &buffer);
-	mutex_unlock(&battery->lock);
+
+	status =
+	    acpi_evaluate_object(acpi_battery_handle(battery), "_BST", NULL,
+				 &buffer);
 	if (ACPI_FAILURE(status)) {
 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _BST"));
 		return -ENODEV;
@@ -337,10 +336,9 @@
 
 	arg0.integer.value = alarm;
 
-	mutex_lock(&battery->lock);
-	status = acpi_evaluate_object(acpi_battery_handle(battery), "_BTP",
+	status =
+	    acpi_evaluate_object(acpi_battery_handle(battery), "_BTP",
 				 &arg_list, NULL);
-	mutex_unlock(&battery->lock);
 	if (ACPI_FAILURE(status))
 		return -ENODEV;
 
@@ -660,6 +658,8 @@
 	if (!battery || (count > sizeof(alarm_string) - 1))
 		return -EINVAL;
 
+	mutex_lock(&battery->mutex);
+
 	result = acpi_battery_update(battery, 1, &update_result);
 	if (result) {
 		result = -ENODEV;
@@ -688,7 +688,9 @@
 	acpi_battery_check_result(battery, result);
 
 	if (!result)
-		return count;
+		result = count;
+
+	mutex_unlock(&battery->mutex);
 
 	return result;
 }
@@ -712,6 +714,8 @@
 	int update_result = ACPI_BATTERY_NONE_UPDATE;
 	int update = 0;
 
+	mutex_lock(&battery->mutex);
+
 	update = (get_seconds() - battery->update_time[fid] >= update_time);
 	update = (update | battery->flags.update[fid]);
 
@@ -729,6 +733,7 @@
 	result = acpi_read_funcs[fid].print(seq, result);
 	acpi_battery_check_result(battery, result);
 	battery->flags.update[fid] = result;
+	mutex_unlock(&battery->mutex);
 	return result;
 }
 
@@ -892,7 +897,10 @@
 	if (!battery)
 		return -ENOMEM;
 
-	mutex_init(&battery->lock);
+	mutex_init(&battery->mutex);
+
+	mutex_lock(&battery->mutex);
+
 	battery->device = device;
 	strcpy(acpi_device_name(device), ACPI_BATTERY_DEVICE_NAME);
 	strcpy(acpi_device_class(device), ACPI_BATTERY_CLASS);
@@ -928,6 +936,7 @@
 		kfree(battery);
 	}
 
+	mutex_unlock(&battery->mutex);
 
 	return result;
 }
@@ -942,6 +951,8 @@
 
 	battery = acpi_driver_data(device);
 
+	mutex_lock(&battery->mutex);
+
 	status = acpi_remove_notify_handler(device->handle,
 					    ACPI_ALL_NOTIFY,
 					    acpi_battery_notify);
@@ -952,7 +963,9 @@
 
 	kfree(battery->bst_data.pointer);
 
-	mutex_destroy(&battery->lock);
+	mutex_unlock(&battery->mutex);
+
+	mutex_destroy(&battery->mutex);
 
 	kfree(battery);