---

yaml
---
r: 350851
b: refs/heads/master
c: c511cc1
h: refs/heads/master
i:
  350849: eb6c6bf
  350847: 21bf59e
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: bfee26dba0f373ebe4e6f0b293d078b02f9f7f69
+refs/heads/master: c511cc1990bbc263c3f8a2ef4d7d613a3b40ffe2

trunk/drivers/acpi/scan.c

@@ -52,6 +52,7 @@ static const struct acpi_device_id acpi_platform_device_ids[] = {
 
 static LIST_HEAD(acpi_device_list);
 static LIST_HEAD(acpi_bus_id_list);
+static DEFINE_MUTEX(acpi_scan_lock);
 DEFINE_MUTEX(acpi_device_lock);
 LIST_HEAD(acpi_wakeup_device_list);
 
@@ -1587,19 +1588,22 @@ static acpi_status acpi_bus_device_attach(acpi_handle handle, u32 lvl_not_used,
 int acpi_bus_scan(acpi_handle handle)
 {
 	void *device = NULL;
+	int error = 0;
+
+	mutex_lock(&acpi_scan_lock);
 
 	if (ACPI_SUCCESS(acpi_bus_check_add(handle, 0, NULL, &device)))
 		acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
 				    acpi_bus_check_add, NULL, NULL, &device);
 
 	if (!device)
-		return -ENODEV;
-
-	if (ACPI_SUCCESS(acpi_bus_device_attach(handle, 0, NULL, NULL)))
+		error = -ENODEV;
+	else if (ACPI_SUCCESS(acpi_bus_device_attach(handle, 0, NULL, NULL)))
 		acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
 				    acpi_bus_device_attach, NULL, NULL, NULL);
 
-	return 0;
+	mutex_unlock(&acpi_scan_lock);
+	return error;
 }
 EXPORT_SYMBOL(acpi_bus_scan);
 
@@ -1628,6 +1632,8 @@ static acpi_status acpi_bus_remove(acpi_handle handle, u32 lvl_not_used,
 
 void acpi_bus_trim(struct acpi_device *start)
 {
+	mutex_lock(&acpi_scan_lock);
+
 	/*
 	 * Execute acpi_bus_device_detach() as a post-order callback to detach
 	 * all ACPI drivers from the device nodes being removed.
@@ -1642,6 +1648,8 @@ void acpi_bus_trim(struct acpi_device *start)
 	acpi_walk_namespace(ACPI_TYPE_ANY, start->handle, ACPI_UINT32_MAX, NULL,
 			    acpi_bus_remove, NULL, NULL);
 	acpi_bus_remove(start->handle, 0, NULL, NULL);
+
+	mutex_unlock(&acpi_scan_lock);
 }
 EXPORT_SYMBOL_GPL(acpi_bus_trim);