Commit 70a7fb80 authored Dec 02, 2015 by Thierry Reding Committed by Mark Brown Dec 02, 2015

regulator: core: Fix nested locking of supplies



Commit fa731ac7 ("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: fa731ac7 ("regulator: core: avoid unused variable warning")
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

parent 49a6bb7a

drivers/regulator/core.c

+9 −2

Original line number	Diff line number	Diff line
		@@ -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
		@@ -140,8 +148,7 @@ static void regulator_lock_supply(struct regulator_dev *rdev)
		{
		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);
		}

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