[PATCH] regulator: Add lockdep asserts to help detecting locking misuse

From: Krzysztof Kozlowski
Date: Sun Jun 28 2015 - 20:04:43 EST


Add lockdep_assert_held_once() to functions explicitly mentioning that
rdev or regulator_list mutex must be held. Using WARN_ONCE shouldn't
pollute the dmesg to much.

The patch (if CONFIG_LOCKDEP enabled) will show warnings in certain
regulators calling regulator_notifier_call_chain() without rdev->mutex
held.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
drivers/regulator/core.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index c9f72019bd68..68b616580533 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -640,6 +640,8 @@ static int drms_uA_update(struct regulator_dev *rdev)
int current_uA = 0, output_uV, input_uV, err;
unsigned int mode;

+ lockdep_assert_held_once(&rdev->mutex);
+
/*
* first check to see if we can set modes at all, otherwise just
* tell the consumer everything is OK.
@@ -760,6 +762,8 @@ static int suspend_set_state(struct regulator_dev *rdev,
/* locks held by caller */
static int suspend_prepare(struct regulator_dev *rdev, suspend_state_t state)
{
+ lockdep_assert_held_once(&rdev->mutex);
+
if (!rdev->constraints)
return -EINVAL;

@@ -1587,6 +1591,8 @@ static void _regulator_put(struct regulator *regulator)
if (regulator == NULL || IS_ERR(regulator))
return;

+ lockdep_assert_held_once(&regulator_list_mutex);
+
rdev = regulator->rdev;

debugfs_remove_recursive(regulator->debugfs);
@@ -1965,6 +1971,8 @@ static int _regulator_enable(struct regulator_dev *rdev)
{
int ret;

+ lockdep_assert_held_once(&rdev->mutex);
+
/* check voltage and requested load before enabling */
if (rdev->constraints &&
(rdev->constraints->valid_ops_mask & REGULATOR_CHANGE_DRMS))
@@ -2065,6 +2073,8 @@ static int _regulator_disable(struct regulator_dev *rdev)
{
int ret = 0;

+ lockdep_assert_held_once(&rdev->mutex);
+
if (WARN(rdev->use_count <= 0,
"unbalanced disables for %s\n", rdev_get_name(rdev)))
return -EIO;
@@ -2143,6 +2153,8 @@ static int _regulator_force_disable(struct regulator_dev *rdev)
{
int ret = 0;

+ lockdep_assert_held_once(&rdev->mutex);
+
ret = _notifier_call_chain(rdev, REGULATOR_EVENT_FORCE_DISABLE |
REGULATOR_EVENT_PRE_DISABLE, NULL);
if (ret & NOTIFY_STOP_MASK)
@@ -3439,6 +3451,8 @@ EXPORT_SYMBOL_GPL(regulator_bulk_free);
int regulator_notifier_call_chain(struct regulator_dev *rdev,
unsigned long event, void *data)
{
+ lockdep_assert_held_once(&rdev->mutex);
+
_notifier_call_chain(rdev, event, data);
return NOTIFY_DONE;

--
2.1.4

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