PM / Runtime: fix recursive locking warning of lockdep from rpm_resume()

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>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 1dd8676..126ca49 100644 (file)
--- 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) {