diff --git a/include/proto/stream_interface.h b/include/proto/stream_interface.h
index c2c5310..7bab7ff 100644
--- a/include/proto/stream_interface.h
+++ b/include/proto/stream_interface.h
@@ -388,15 +388,13 @@
 /* Calls chk_rcv on the connection using the data layer */
 static inline void si_chk_rcv(struct stream_interface *si)
 {
-	if (si->ops->chk_rcv)
-		si->ops->chk_rcv(si);
+	si->ops->chk_rcv(si);
 }
 
 /* Calls chk_snd on the connection using the data layer */
 static inline void si_chk_snd(struct stream_interface *si)
 {
-	if (si->ops->chk_snd)
-		si->ops->chk_snd(si);
+	si->ops->chk_snd(si);
 }
 
 /* Calls chk_snd on the connection using the ctrl layer */
diff --git a/include/types/stream_interface.h b/include/types/stream_interface.h
index 3a9895e..0362afd 100644
--- a/include/types/stream_interface.h
+++ b/include/types/stream_interface.h
@@ -106,11 +106,11 @@
 
 /* operations available on a stream-interface */
 struct si_ops {
-	void (*update)(struct stream_interface *);  /* I/O update function */
-	void (*chk_rcv)(struct stream_interface *); /* chk_rcv function */
-	void (*chk_snd)(struct stream_interface *); /* chk_snd function */
-	void (*shutr)(struct stream_interface *);   /* shut read function */
-	void (*shutw)(struct stream_interface *);   /* shut write function */
+	void (*update)(struct stream_interface *);  /* I/O update function, may be null */
+	void (*chk_rcv)(struct stream_interface *); /* chk_rcv function, may not be null */
+	void (*chk_snd)(struct stream_interface *); /* chk_snd function, may not be null */
+	void (*shutr)(struct stream_interface *);   /* shut read function, may not be null */
+	void (*shutw)(struct stream_interface *);   /* shut write function, may not be null */
 };
 
 #endif /* _TYPES_STREAM_INTERFACE_H */