[PATCH 3.14 65/92] ACPI / scan: Annotate physical_node_lock in acpi_scan_is_offline()

Greg Kroah-Hartman
2015-05-02T19:47:23Z

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

commit 4c533c801d1c9b5c38458a0e7516e0cf50643782 upstream.

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

Fixes: caa73ea158de (ACPI / hotplug / driver core: Handle containers in a special way)
Reported-and-tested-by: Xie XiuQi <xiexiuqi@huawei.com>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/acpi/scan.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -192,7 +192,11 @@ 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) {