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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 b3ae38966d
commit 3430936a01
1 changed files with 28 additions and 24 deletions
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6
drivers/regulator/core.c
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@ -2925,6 +2925,7 @@ static int _regulator_enable(struct regulator *regulator)
/* Fallthrough on positive return values - already enabled */
}
if (regulator->enable_count == 1)
rdev->use_count++;
return 0;
@ -3000,10 +3001,12 @@ 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;
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)) {
@ -3032,6 +3035,7 @@ static int _regulator_disable(struct regulator *regulator)
} else if (rdev->use_count > 1) {
rdev->use_count--;
}
}
if (ret == 0)
ret = _regulator_handle_consumer_disable(regulator);