5.4-stable review patch. If anyone has any objections, please let me know.
------------------
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 87d0cd6f49ca..894915892eaf 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -2658,7 +2658,8 @@ 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;
@@ -2736,37 +2737,40 @@ 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\n"); - _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\n"); + _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)