fsnotify: allow groups to set freeing_mark to null

Most fsnotify listeners (all but inotify) do not care about marks being
freed.  Allow groups to set freeing_mark to null and do not call any
function if it is set that way.

Signed-off-by: Eric Paris <eparis@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index 0a499d2c6191..c8a07c65482b 100644
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -190,7 +190,8 @@ void fsnotify_destroy_mark_by_entry(struct fsnotify_mark_entry *entry)
          * callback to the group function to let it know that this entry
          * is being freed.
          */
-        group->ops->freeing_mark(entry, group);
+        if (group->ops->freeing_mark)
+                group->ops->freeing_mark(entry, group);
 
         /*
          * __fsnotify_update_child_dentry_flags(inode);