summaryrefslogtreecommitdiff
path: root/drivers/regulator
diff options
context:
space:
mode:
authorThierry Reding <treding@nvidia.com>2015-12-02 16:54:50 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-05-04 14:48:50 -0700
commit5a58f809d731c23c0b898d2021903db8dee4466f (patch)
tree289f098a27c6187d12fa7e38fb93b992a520a4d2 /drivers/regulator
parent29c9f634cb132107df3e4f07c8e48b35d04b527b (diff)
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 <broonie@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Fixes: fa731ac7ea04 ("regulator: core: avoid unused variable warning") Signed-off-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/regulator')
-rw-r--r--drivers/regulator/core.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index f71db02fcb71..732ac71b82cd 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
@@ -140,8 +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);
}