fsnotify: introduce fsnotify_get_group()

Introduce fsnotify_get_group() which increments the reference counter of a group.

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/fs/notify/group.c b/fs/notify/group.c
index cfda328..1d57c35 100644
--- a/fs/notify/group.c
+++ b/fs/notify/group.c
@@ -63,6 +63,14 @@
 }
 
 /*
+ * Get reference to a group.
+ */
+void fsnotify_get_group(struct fsnotify_group *group)
+{
+	atomic_inc(&group->refcnt);
+}
+
+/*
  * Drop a reference to a group.  Free it if it's through.
  */
 void fsnotify_put_group(struct fsnotify_group *group)