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Subject[PATCH] regulator: Add lockdep asserts to help detecting locking misuse
Date
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@samsung.com>

---

Warnings for missing locks when calling regulator_notifier_call_chain()
should appear on many regulators except wm8350-regulator.c, e.g.:
da9055-regulator.c, da9062-regulator.c, da9063-regulator.c,
da9211-regulator.c, wm831x-dcdc.c and few more.

The question is whether the lock during that call should be held?
---
drivers/regulator/core.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 443eaab933fc..2d11731db7cb 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.
@@ -758,6 +760,8 @@ 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;

@@ -1555,6 +1559,8 @@ 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);
@@ -1933,6 +1939,8 @@ 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))
@@ -2033,6 +2041,8 @@ 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;
@@ -2111,6 +2121,8 @@ 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)
@@ -3407,6 +3419,8 @@ 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;

--
1.9.1


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