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regulator: core: Only increment use_count when enable_count changes

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[ 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>
This commit is contained in:
Rui Zhang
2023-11-03 15:42:31 +08:00
committed by Greg Kroah-Hartman
parent 19c7132270
commit 37e00ed71e
1 changed files with 28 additions and 24 deletions
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52
drivers/regulator/core.c
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@@ -2768,7 +2768,8 @@ static int _regulator_enable(struct regulator *regulator)
/* Fallthrough on positive return values - already enabled */ /* Fallthrough on positive return values - already enabled */
} }
rdev->use_count++; if (regulator->enable_count == 1)
rdev->use_count++;
return 0; return 0;
@@ -2846,37 +2847,40 @@ static int _regulator_disable(struct regulator *regulator)
lockdep_assert_held_once(&rdev->mutex.base); 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))) "unbalanced disables for %s\n", rdev_get_name(rdev)))
return -EIO; return -EIO;
/* are we the last user and permitted to disable ? */ if (regulator->enable_count == 1) {
if (rdev->use_count == 1 && /* disabling last enable_count from this regulator */
(rdev->constraints && !rdev->constraints->always_on)) { /* are we the last user and permitted to disable ? */
if (rdev->use_count == 1 &&
(rdev->constraints && !rdev->constraints->always_on)) {
/* we are last user */ /* we are last user */
if (regulator_ops_is_valid(rdev, REGULATOR_CHANGE_STATUS)) { if (regulator_ops_is_valid(rdev, REGULATOR_CHANGE_STATUS)) {
ret = _notifier_call_chain(rdev, ret = _notifier_call_chain(rdev,
REGULATOR_EVENT_PRE_DISABLE, REGULATOR_EVENT_PRE_DISABLE,
NULL); NULL);
if (ret & NOTIFY_STOP_MASK) if (ret & NOTIFY_STOP_MASK)
return -EINVAL; return -EINVAL;
ret = _regulator_do_disable(rdev); ret = _regulator_do_disable(rdev);
if (ret < 0) { if (ret < 0) {
rdev_err(rdev, "failed to disable: %pe\n", ERR_PTR(ret)); rdev_err(rdev, "failed to disable: %pe\n", ERR_PTR(ret));
_notifier_call_chain(rdev, _notifier_call_chain(rdev,
REGULATOR_EVENT_ABORT_DISABLE, REGULATOR_EVENT_ABORT_DISABLE,
NULL);
return ret;
}
_notifier_call_chain(rdev, REGULATOR_EVENT_DISABLE,
NULL); NULL);
return ret;
} }
_notifier_call_chain(rdev, REGULATOR_EVENT_DISABLE,
NULL);
}
rdev->use_count = 0; rdev->use_count = 0;
} else if (rdev->use_count > 1) { } else if (rdev->use_count > 1) {
rdev->use_count--; rdev->use_count--;
}
} }
if (ret == 0) if (ret == 0)