fsnotify: pass connp and object type to fsnotify_add_mark()

Instead of passing inode and vfsmount arguments to fsnotify_add_mark()
and its _locked variant, pass an abstract object pointer and the object
type.

The helpers fsnotify_obj_{inode,mount} are added to get the concrete
object pointer from abstract object pointer.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/notify/fsnotify.h

@@ -9,6 +9,16 @@
 
 #include "../mount.h"
 
+static inline struct inode *fsnotify_obj_inode(fsnotify_connp_t *connp)
+{
+	return container_of(connp, struct inode, i_fsnotify_marks);
+}
+
+static inline struct mount *fsnotify_obj_mount(fsnotify_connp_t *connp)
+{
+	return container_of(connp, struct mount, mnt_fsnotify_marks);
+}
+
 /* destroy all events sitting in this groups notification queue */
 extern void fsnotify_flush_notify(struct fsnotify_group *group);