linux-kernel - [PATCH v1] regulator: core: Don't try to remove device links if add failed

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Date:   Thu, 14 Nov 2019 16:04:38 -0800
From:   Saravana Kannan <saravanak@...gle.com>
To:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>
Cc:     Saravana Kannan <saravanak@...gle.com>, kernel-team@...roid.com,
        linux-kernel@...r.kernel.org
Subject: [PATCH v1] regulator: core: Don't try to remove device links if add failed

device_link_add() might not always succeed depending on the type of
device link and the rest of the dependencies in the system. If
device_link_add() didn't succeed, then we shouldn't try to remove the
link later on as it might remove a link someone else created.

Signed-off-by: Saravana Kannan <saravanak@...gle.com>
---
 drivers/regulator/core.c     | 8 ++++++--
 drivers/regulator/internal.h | 1 +
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index a46be221dbdc..6fa790c58db1 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1844,6 +1844,7 @@ struct regulator *_regulator_get(struct device *dev, const char *id,
 	struct regulator_dev *rdev;
 	struct regulator *regulator;
 	const char *devname = dev ? dev_name(dev) : "deviceless";
+	struct device_link *link;
 	int ret;
 
 	if (get_type >= MAX_GET_TYPE) {
@@ -1951,7 +1952,9 @@ struct regulator *_regulator_get(struct device *dev, const char *id,
 			rdev->use_count = 0;
 	}
 
-	device_link_add(dev, &rdev->dev, DL_FLAG_STATELESS);
+	link = device_link_add(dev, &rdev->dev, DL_FLAG_STATELESS);
+	if (!IS_ERR_OR_NULL(link))
+		regulator->device_link = true;
 
 	return regulator;
 }
@@ -2046,7 +2049,8 @@ static void _regulator_put(struct regulator *regulator)
 	debugfs_remove_recursive(regulator->debugfs);
 
 	if (regulator->dev) {
-		device_link_remove(regulator->dev, &rdev->dev);
+		if (regulator->device_link)
+			device_link_remove(regulator->dev, &rdev->dev);
 
 		/* remove any sysfs entries */
 		sysfs_remove_link(&rdev->dev.kobj, regulator->supply_name);
diff --git a/drivers/regulator/internal.h b/drivers/regulator/internal.h
index 83ae442f515b..2391b565ef11 100644
--- a/drivers/regulator/internal.h
+++ b/drivers/regulator/internal.h
@@ -36,6 +36,7 @@ struct regulator {
 	struct list_head list;
 	unsigned int always_on:1;
 	unsigned int bypass:1;
+	unsigned int device_link:1;
 	int uA_load;
 	unsigned int enable_count;
 	unsigned int deferred_disables;
-- 
2.24.0.432.g9d3f5f5b63-goog