[PATCH] PM: runtime: fix recursive locking warning of lockdep from rpm_resume

[tom.leiming@gmail.com]

From: Ming Lei <tom.leiming@gmail.com>

For device with no_callbacks flag set, its power lock and its parent's
power lock may be held nestedly in rpm_resume, so we should take
spin_lock_nested(lock, SINGLE_DEPTH_NESTING) to acquire parent power lock
to avoid lockdep warning.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
---
 drivers/base/power/runtime.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 1dd8676..126ca49 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -503,7 +503,7 @@ static int rpm_resume(struct device *dev, int rpmflags)
 	 * the resume will actually succeed.
 	 */
 	if (dev->power.no_callbacks && !parent && dev->parent) {
-		spin_lock(&dev->parent->power.lock);
+		spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
 		if (dev->parent->power.disable_depth > 0
 		    || dev->parent->power.ignore_children
 		    || dev->parent->power.runtime_status == RPM_ACTIVE) {
-- 
1.7.3