Messages in this thread Patch in this message | | | From | Krzysztof Kozlowski <> | Subject | [PATCH] regulator: Add lockdep asserts to help detecting locking misuse | Date | Wed, 10 Jun 2015 15:23:12 +0900 |
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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>
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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(®ulator_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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