regulator: core: Fix nested locking of supplies
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 <broonie@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Fixes: Fixes: fa731ac7ea04 ("regulator: core: avoid unused variable warning")
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index f71db02..732ac71 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -132,6 +132,14 @@
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
@@ -140,8 +148,7 @@
{
int i;
- mutex_lock(&rdev->mutex);
- for (i = 1; rdev; rdev = rdev->supply->rdev, i++)
+ for (i = 0; rdev; rdev = rdev_get_supply(rdev), i++)
mutex_lock_nested(&rdev->mutex, i);
}