From: Thierry Reding Date: Wed, 2 Dec 2015 15:54:50 +0000 (+0100) Subject: regulator: core: Fix nested locking of supplies X-Git-Tag: firefly_0821_release~176^2~4^2~50^2~207 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=b1999fa6e8145305a6c8bda30ea20783717708e6;p=firefly-linux-kernel-4.4.55.git regulator: core: Fix nested locking of supplies commit 70a7fb80e85ae7f78f8e90cec3fbd862ea6a4d4b upstream. Commit fa731ac7ea04 ("regulator: core: avoid unused variable warning") introduced a subtle change in how supplies are locked. Where previously code was always locking the regulator of the current iteration, the new implementation only locks the regulator if it has a supply. For any given power tree that means that the root will never get locked. On the other hand the regulator_unlock_supply() will still release all the locks, which in turn causes the lock debugging code to warn about a mutex being unlocked which wasn't locked. Cc: Mark Brown Cc: Arnd Bergmann Fixes: Fixes: fa731ac7ea04 ("regulator: core: avoid unused variable warning") Signed-off-by: Thierry Reding Signed-off-by: Mark Brown Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index c70017d5f74b..7b94b8ee087c 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -132,6 +132,14 @@ static bool have_full_constraints(void) return has_full_constraints || of_have_populated_dt(); } +static inline struct regulator_dev *rdev_get_supply(struct regulator_dev *rdev) +{ + if (rdev && rdev->supply) + return rdev->supply->rdev; + + return NULL; +} + /** * regulator_lock_supply - lock a regulator and its supplies * @rdev: regulator source @@ -140,7 +148,7 @@ static void regulator_lock_supply(struct regulator_dev *rdev) { int i; - for (i = 0; rdev->supply; rdev = rdev->supply->rdev, i++) + for (i = 0; rdev->supply; rdev = rdev_get_supply(rdev), i++) mutex_lock_nested(&rdev->mutex, i); }