uwb: fix device reference leaks

commit d6124b40 upstream.

This subsystem consistently fails to drop the device reference taken by
class_find_device().

Note that some of these lookup functions already take a reference to the
returned data, while others claim no reference is needed (or does not
seem need one).

Fixes: 183b9b59 ("uwb: add the UWB stack (core files)")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2:
 - Drop change to uwb_rc_class_device_exists()
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/uwb/lc-rc.c

@@ -56,8 +56,11 @@ static struct uwb_rc *uwb_rc_find_by_index(int index)
 	struct uwb_rc *rc = NULL;
 
 	dev = class_find_device(&uwb_rc_class, NULL, &index, uwb_rc_index_match);
-	if (dev)
+	if (dev) {
 		rc = dev_get_drvdata(dev);
+		put_device(dev);
+	}
+
 	return rc;
 }
 
@@ -368,7 +371,9 @@ struct uwb_rc *__uwb_rc_try_get(struct uwb_rc *target_rc)
 	if (dev) {
 		rc = dev_get_drvdata(dev);
 		__uwb_rc_get(rc);
+		put_device(dev);
 	}
+
 	return rc;
 }
 EXPORT_SYMBOL_GPL(__uwb_rc_try_get);
@@ -421,8 +426,11 @@ struct uwb_rc *uwb_rc_get_by_grandpa(const struct device *grandpa_dev)
 
 	dev = class_find_device(&uwb_rc_class, NULL, (void *)grandpa_dev,
 				find_rc_grandpa);
-	if (dev)
+	if (dev) {
 		rc = dev_get_drvdata(dev);
+		put_device(dev);
+	}
+
 	return rc;
 }
 EXPORT_SYMBOL_GPL(uwb_rc_get_by_grandpa);
@@ -455,8 +463,10 @@ struct uwb_rc *uwb_rc_get_by_dev(const struct uwb_dev_addr *addr)
 
 	dev = class_find_device(&uwb_rc_class, NULL, (void *)addr,
 				find_rc_dev);
-	if (dev)
+	if (dev) {
 		rc = dev_get_drvdata(dev);
+		put_device(dev);
+	}
 
 	return rc;
 }