[PATCH v2 3/3] regulator: core: Add locking to debugfs regulator_summary

From: Douglas Anderson
Date: Thu Aug 16 2018 - 16:29:08 EST


Most functions that access the rdev lock the rdev mutex before looking
at data. ...but not the code that implements the debugfs
regulator_summary. It probably should though, so let's do it.

Note: this fixes no known issues. The problem was found only by code
inspection.

Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
---

Changes in v2: None

drivers/regulator/core.c | 51 ++++++++++++++++++++++++----------------
1 file changed, 31 insertions(+), 20 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 1e2dc8d09075..d350bcabdf20 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -3461,21 +3461,23 @@ int regulator_set_current_limit(struct regulator *regulator,
}
EXPORT_SYMBOL_GPL(regulator_set_current_limit);

+static int _regulator_get_current_limit_unlocked(struct regulator_dev *rdev)
+{
+ /* sanity check */
+ if (!rdev->desc->ops->get_current_limit)
+ return -EINVAL;
+
+ return rdev->desc->ops->get_current_limit(rdev);
+}
+
static int _regulator_get_current_limit(struct regulator_dev *rdev)
{
int ret;

regulator_lock(rdev);
-
- /* sanity check */
- if (!rdev->desc->ops->get_current_limit) {
- ret = -EINVAL;
- goto out;
- }
-
- ret = rdev->desc->ops->get_current_limit(rdev);
-out:
+ ret = _regulator_get_current_limit_unlocked(rdev);
regulator_unlock(rdev);
+
return ret;
}

@@ -3540,21 +3542,23 @@ int regulator_set_mode(struct regulator *regulator, unsigned int mode)
}
EXPORT_SYMBOL_GPL(regulator_set_mode);

+static unsigned int _regulator_get_mode_unlocked(struct regulator_dev *rdev)
+{
+ /* sanity check */
+ if (!rdev->desc->ops->get_mode)
+ return -EINVAL;
+
+ return rdev->desc->ops->get_mode(rdev);
+}
+
static unsigned int _regulator_get_mode(struct regulator_dev *rdev)
{
int ret;

regulator_lock(rdev);
-
- /* sanity check */
- if (!rdev->desc->ops->get_mode) {
- ret = -EINVAL;
- goto out;
- }
-
- ret = rdev->desc->ops->get_mode(rdev);
-out:
+ ret = _regulator_get_mode_unlocked(rdev);
regulator_unlock(rdev);
+
return ret;
}

@@ -4661,18 +4665,23 @@ static void regulator_summary_show_subtree(struct seq_file *s,
struct regulation_constraints *c;
struct regulator *consumer;
struct summary_data summary_data;
+ unsigned int opmode;

if (!rdev)
return;

+ regulator_lock_nested(rdev, level);
+
+ opmode = _regulator_get_mode_unlocked(rdev);
seq_printf(s, "%*s%-*s %3d %4d %6d %7s ",
level * 3 + 1, "",
30 - level * 3, rdev_get_name(rdev),
rdev->use_count, rdev->open_count, rdev->bypass_count,
- regulator_opmode_to_str(_regulator_get_mode(rdev)));
+ regulator_opmode_to_str(opmode));

seq_printf(s, "%5dmV ", _regulator_get_voltage(rdev) / 1000);
- seq_printf(s, "%5dmA ", _regulator_get_current_limit(rdev) / 1000);
+ seq_printf(s, "%5dmA ",
+ _regulator_get_current_limit_unlocked(rdev) / 1000);

c = rdev->constraints;
if (c) {
@@ -4719,6 +4728,8 @@ static void regulator_summary_show_subtree(struct seq_file *s,

class_for_each_device(&regulator_class, NULL, &summary_data,
regulator_summary_show_children);
+
+ regulator_unlock(rdev);
}

static int regulator_summary_show_roots(struct device *dev, void *data)
--
2.18.0.865.gffc8e1a3cd6-goog