i2c: dev: check return value when calling dev_set_name()

If dev_set_name() fails, the dev_name() is null, check the return
value of dev_set_name() to avoid the null-ptr-deref.

Fixes: 1413ef6 ("i2c: dev: Fix the race between the release of i2c_dev and cdev")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Author: andy-shev

drivers/i2c/i2c-dev.c

@@ -668,16 +668,21 @@ static int i2cdev_attach_adapter(struct device *dev, void *dummy)
 	i2c_dev->dev.class = i2c_dev_class;
 	i2c_dev->dev.parent = &adap->dev;
 	i2c_dev->dev.release = i2cdev_dev_release;
-	dev_set_name(&i2c_dev->dev, "i2c-%d", adap->nr);
+
+	res = dev_set_name(&i2c_dev->dev, "i2c-%d", adap->nr);
+	if (res)
+		goto err_put_i2c_dev;
 
 	res = cdev_device_add(&i2c_dev->cdev, &i2c_dev->dev);
-	if (res) {
-		put_i2c_dev(i2c_dev, false);
-		return res;
-	}
+	if (res)
+		goto err_put_i2c_dev;
 
 	pr_debug("adapter [%s] registered as minor %d\n", adap->name, adap->nr);
 	return 0;
+
+err_put_i2c_dev:
+	put_i2c_dev(i2c_dev, false);
+	return res;
 }
 
 static int i2cdev_detach_adapter(struct device *dev, void *dummy)