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regulator: core: Fix nested locking of supplies 

Commit fa731ac7ea ("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: fa731ac7ea ("regulator: core: avoid unused variable warning")
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
hifive-unleashed-5.1
Thierry Reding 2015-12-02 16:54:50 +01:00 committed by Mark Brown
parent 49a6bb7a1c
commit 70a7fb80e8
1 changed files with 9 additions and 2 deletions
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11
drivers/regulator/core.c
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@ -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);
}