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path: root/drivers/regulator/core.c
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Diffstat (limited to 'drivers/regulator/core.c')
-rw-r--r--drivers/regulator/core.c44
1 files changed, 33 insertions, 11 deletions
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index ca03d8e70bd1..67a768fe5b2a 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1813,13 +1813,13 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
{
struct regulator_dev *r;
struct device *dev = rdev->dev.parent;
- int ret;
+ int ret = 0;
/* No supply to resolve? */
if (!rdev->supply_name)
return 0;
- /* Supply already resolved? */
+ /* Supply already resolved? (fast-path without locking contention) */
if (rdev->supply)
return 0;
@@ -1829,7 +1829,7 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
/* Did the lookup explicitly defer for us? */
if (ret == -EPROBE_DEFER)
- return ret;
+ goto out;
if (have_full_constraints()) {
r = dummy_regulator_rdev;
@@ -1837,15 +1837,18 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
} else {
dev_err(dev, "Failed to resolve %s-supply for %s\n",
rdev->supply_name, rdev->desc->name);
- return -EPROBE_DEFER;
+ ret = -EPROBE_DEFER;
+ goto out;
}
}
if (r == rdev) {
dev_err(dev, "Supply for %s (%s) resolved to itself\n",
rdev->desc->name, rdev->supply_name);
- if (!have_full_constraints())
- return -EINVAL;
+ if (!have_full_constraints()) {
+ ret = -EINVAL;
+ goto out;
+ }
r = dummy_regulator_rdev;
get_device(&r->dev);
}
@@ -1859,7 +1862,8 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
if (r->dev.parent && r->dev.parent != rdev->dev.parent) {
if (!device_is_bound(r->dev.parent)) {
put_device(&r->dev);
- return -EPROBE_DEFER;
+ ret = -EPROBE_DEFER;
+ goto out;
}
}
@@ -1867,15 +1871,32 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
ret = regulator_resolve_supply(r);
if (ret < 0) {
put_device(&r->dev);
- return ret;
+ goto out;
+ }
+
+ /*
+ * Recheck rdev->supply with rdev->mutex lock held to avoid a race
+ * between rdev->supply null check and setting rdev->supply in
+ * set_supply() from concurrent tasks.
+ */
+ regulator_lock(rdev);
+
+ /* Supply just resolved by a concurrent task? */
+ if (rdev->supply) {
+ regulator_unlock(rdev);
+ put_device(&r->dev);
+ goto out;
}
ret = set_supply(rdev, r);
if (ret < 0) {
+ regulator_unlock(rdev);
put_device(&r->dev);
- return ret;
+ goto out;
}
+ regulator_unlock(rdev);
+
/*
* In set_machine_constraints() we may have turned this regulator on
* but we couldn't propagate to the supply if it hadn't been resolved
@@ -1886,11 +1907,12 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
if (ret < 0) {
_regulator_put(rdev->supply);
rdev->supply = NULL;
- return ret;
+ goto out;
}
}
- return 0;
+out:
+ return ret;
}
/* Internal regulator request function */