regulator: core: grab supply info before unlocking

It is necessary to check if there is a supply while still holding the regulator lock. Otherwise a theoretical race can occur that someone else can add a supply and then we incorrectly try to unlock that newly added regulator.

---
patch against next-20160421

 drivers/regulator/core.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index 9348c78..629f92f 100644
@@ -161,10 +161,10 @@ static void regulator_unlock_supply(struct regulator_dev *rdev)
 	struct regulator *supply;
 
 	while (1) {
-		mutex_unlock(&rdev->mutex);
 		supply = rdev->supply;
+		mutex_unlock(&rdev->mutex);
 
-		if (!rdev->supply)
+		if (!supply)
 			return;
 
 		rdev = supply->rdev;

1.7.10.4

I don't understand this. What do you mean by "add a supply"?