[PATCH] ACPI / scan: Annotate physical_node_lock in acpi_scan_is_offline()

["Rafael J. Wysocki" <rjw@rjwysocki.net>]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

acpi_scan_is_offline() may be called under the physical_node_lock
of the given device object's parent, so prevent lockdep from
complaining about that by annotating that instance with
SINGLE_DEPTH_NESTING.

Reported-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/scan.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -298,7 +298,11 @@ bool acpi_scan_is_offline(struct acpi_de
 	struct acpi_device_physical_node *pn;
 	bool offline = true;
 
-	mutex_lock(&adev->physical_node_lock);
+	/*
+	 * acpi_container_offline() calls this for all of the container's
+	 * children under the container's physical_node_lock lock.
+	 */
+	mutex_lock_nested(&adev->physical_node_lock, SINGLE_DEPTH_NESTING);
 
 	list_for_each_entry(pn, &adev->physical_node_list, node)
 		if (device_supports_offline(pn->dev) && !pn->dev->offline) {