[PATCH 4.14 42/94] regulator: push allocation in set_consumer_device_supply() out of lock

Greg Kroah-Hartman
2020-09-21T16:38:23Z

From: Michał Mirosław <mirq-linux@rere.qmqm.pl>

commit 5c06540165d443c6455123eb48e7f1a9b618ab34 upstream.

Pull regulator_list_mutex into set_consumer_device_supply() and keep
allocations outside of it. Fourth of the fs_reclaim deadlock case.

Fixes: 45389c47526d ("regulator: core: Add early supply resolution for regulators")
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/f0380bdb3d60aeefa9693c4e234d2dcda7e56747.1597195321.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/regulator/core.c | 46 ++++++++++++++++++++++++++--------------------
1 file changed, 26 insertions(+), 20 deletions(-)

--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1192,7 +1192,7 @@ static int set_consumer_device_supply(st
const char *consumer_dev_name,
const char *supply)
{
- struct regulator_map *node;
+ struct regulator_map *node, *new_node;
int has_dev;

if (supply == NULL)
@@ -1203,6 +1203,22 @@ static int set_consumer_device_supply(st
else
has_dev = 0;

+ new_node = kzalloc(sizeof(struct regulator_map), GFP_KERNEL);
+ if (new_node == NULL)
+ return -ENOMEM;
+
+ new_node->regulator = rdev;
+ new_node->supply = supply;
+
+ if (has_dev) {
+ new_node->dev_name = kstrdup(consumer_dev_name, GFP_KERNEL);
+ if (new_node->dev_name == NULL) {
+ kfree(new_node);
+ return -ENOMEM;
+ }
+ }
+
+ mutex_lock(&regulator_list_mutex);
list_for_each_entry(node, &regulator_map_list, list) {
if (node->dev_name && consumer_dev_name) {
if (strcmp(node->dev_name, consumer_dev_name) != 0)
@@ -1220,26 +1236,19 @@ static int set_consumer_device_supply(st
node->regulator->desc->name,
supply,
dev_name(&rdev->dev), rdev_get_name(rdev));
- return -EBUSY;
+ goto fail;
}

- node = kzalloc(sizeof(struct regulator_map), GFP_KERNEL);
- if (node == NULL)
- return -ENOMEM;
-
- node->regulator = rdev;
- node->supply = supply;
-
- if (has_dev) {
- node->dev_name = kstrdup(consumer_dev_name, GFP_KERNEL);
- if (node->dev_name == NULL) {
- kfree(node);
- return -ENOMEM;
- }
- }
+ list_add(&new_node->list, &regulator_map_list);
+ mutex_unlock(&regulator_list_mutex);

- list_add(&node->list, &regulator_map_list);
return 0;
+
+fail:
+ mutex_unlock(&regulator_list_mutex);
+ kfree(new_node->dev_name);
+ kfree(new_node);
+ return -EBUSY;
}

static void unset_regulator_supplies(struct regulator_dev *rdev)
@@ -4095,19 +4104,16 @@ regulator_register(const struct regulato

/* add consumers devices */
if (init_data) {
- mutex_lock(&regulator_list_mutex);
for (i = 0; i < init_data->num_consumer_supplies; i++) {
ret = set_consumer_device_supply(rdev,
init_data->consumer_supplies[i].dev_name,
init_data->consumer_supplies[i].supply);
if (ret < 0) {
- mutex_unlock(&regulator_list_mutex);
dev_err(dev, "Failed to set supply %s\n",
init_data->consumer_supplies[i].supply);
goto unset_supplies;
}
}
- mutex_unlock(&regulator_list_mutex);
}

if (!rdev->desc->ops->get_voltage &&