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Date:   Wed, 12 Aug 2020 03:31:36 +0200
From:   Michał Mirosław <mirq-linux@...e.qmqm.pl>
To:     Dmitry Osipenko <digetx@...il.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Vladimir Zapolskiy <vz@...ia.com>
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH v2 4/7] regulator: push allocation in
 set_consumer_device_supply() out of lock

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

Cc: stable@...r.kernel.org
Fixes: 45389c47526d ("regulator: core: Add early supply resolution for regulators")
Signed-off-by: Michał Mirosław <mirq-linux@...e.qmqm.pl>
---
v2: fix new node leak reported kernel test robot <lkp@...el.com>
---
 drivers/regulator/core.c | 46 +++++++++++++++++++++++-----------------
 1 file changed, 26 insertions(+), 20 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index c95397798275..71749f48caee 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1434,7 +1434,7 @@ static int set_consumer_device_supply(struct regulator_dev *rdev,
 				      const char *consumer_dev_name,
 				      const char *supply)
 {
-	struct regulator_map *node;
+	struct regulator_map *node, *new_node;
 	int has_dev;
 
 	if (supply == NULL)
@@ -1445,6 +1445,22 @@ static int set_consumer_device_supply(struct regulator_dev *rdev,
 	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)
@@ -1462,26 +1478,19 @@ static int set_consumer_device_supply(struct regulator_dev *rdev,
 			 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;
+	list_add(&new_node->list, &regulator_map_list);
+	mutex_unlock(&regulator_list_mutex);
 
-	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(&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)
@@ -5239,19 +5248,16 @@ regulator_register(const struct regulator_desc *regulator_desc,
 
 	/* 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 &&
-- 
2.20.1

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