[PATCH 6.1 014/219] regulator: core: Only increment use_count when enable_count changes

Greg Kroah-Hartman
2024-02-03T04:08:54Z

From: Rui Zhang <zr.zhang@vivo.com>

[ Upstream commit 7993d3a9c34f609c02171e115fd12c10e2105ff4 ]

The use_count of a regulator should only be incremented when the
enable_count changes from 0 to 1. Similarly, the use_count should
only be decremented when the enable_count changes from 1 to 0.

In the previous implementation, use_count was sometimes decremented
to 0 when some consumer called unbalanced disable,
leading to unexpected disable even the regulator is enabled by
other consumers. With this change, the use_count accurately reflects
the number of users which the regulator is enabled.

This should make things more robust in the case where a consumer does
leak references.

Signed-off-by: Rui Zhang <zr.zhang@vivo.com>
Link: https://lore.kernel.org/r/20231103074231.8031-1-zr.zhang@vivo.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/regulator/core.c | 56 +++++++++++++++++++++-------------------
1 file changed, 30 insertions(+), 26 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 34d3d8281906..c8702011b761 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -2925,7 +2925,8 @@ static int _regulator_enable(struct regulator *regulator)
/* Fallthrough on positive return values - already enabled */
}

- rdev->use_count++;
+ if (regulator->enable_count == 1)
+ rdev->use_count++;

return 0;

@@ -3000,37 +3001,40 @@ static int _regulator_disable(struct regulator *regulator)

lockdep_assert_held_once(&rdev->mutex.base);

- if (WARN(rdev->use_count <= 0,
+ if (WARN(regulator->enable_count == 0,
"unbalanced disables for %s\n", rdev_get_name(rdev)))
return -EIO;

- /* are we the last user and permitted to disable ? */
- if (rdev->use_count == 1 &&
- (rdev->constraints && !rdev->constraints->always_on)) {
-
- /* we are last user */
- if (regulator_ops_is_valid(rdev, REGULATOR_CHANGE_STATUS)) {
- ret = _notifier_call_chain(rdev,
- REGULATOR_EVENT_PRE_DISABLE,
- NULL);
- if (ret & NOTIFY_STOP_MASK)
- return -EINVAL;
-
- ret = _regulator_do_disable(rdev);
- if (ret < 0) {
- rdev_err(rdev, "failed to disable: %pe\n", ERR_PTR(ret));
- _notifier_call_chain(rdev,
- REGULATOR_EVENT_ABORT_DISABLE,
+ if (regulator->enable_count == 1) {
+ /* disabling last enable_count from this regulator */
+ /* are we the last user and permitted to disable ? */
+ if (rdev->use_count == 1 &&
+ (rdev->constraints && !rdev->constraints->always_on)) {
+
+ /* we are last user */
+ if (regulator_ops_is_valid(rdev, REGULATOR_CHANGE_STATUS)) {
+ ret = _notifier_call_chain(rdev,
+ REGULATOR_EVENT_PRE_DISABLE,
+ NULL);
+ if (ret & NOTIFY_STOP_MASK)
+ return -EINVAL;
+
+ ret = _regulator_do_disable(rdev);
+ if (ret < 0) {
+ rdev_err(rdev, "failed to disable: %pe\n", ERR_PTR(ret));
+ _notifier_call_chain(rdev,
+ REGULATOR_EVENT_ABORT_DISABLE,
+ NULL);
+ return ret;
+ }
+ _notifier_call_chain(rdev, REGULATOR_EVENT_DISABLE,
NULL);
- return ret;
}
- _notifier_call_chain(rdev, REGULATOR_EVENT_DISABLE,
- NULL);
- }

- rdev->use_count = 0;
- } else if (rdev->use_count > 1) {
- rdev->use_count--;
+ rdev->use_count = 0;
+ } else if (rdev->use_count > 1) {
+ rdev->use_count--;
+ }
}

if (ret == 0)
--
2.43.0