diff --git a/src/include/ipxe/list.h b/src/include/ipxe/list.h
index 4905aaa3..8dc74139 100644
--- a/src/include/ipxe/list.h
+++ b/src/include/ipxe/list.h
@@ -170,6 +170,18 @@ static inline int list_empty ( const struct list_head *list ) {
 	  ( type * ) NULL :				\
 	  list_entry ( (list)->next, type, member ) )
 
+/**
+ * Iterate over a list
+ *
+ * @v pos		Iterator
+ * @v head		List head
+ */
+#define list_for_each( pos, head )					      \
+	for ( list_check ( (head) ),					      \
+	      pos = (head)->next;					      \
+	      pos != (head);						      \
+	      pos = (pos)->next )
+
 /**
  * Iterate over entries in a list
  *
@@ -212,6 +224,38 @@ static inline int list_empty ( const struct list_head *list ) {
 	      pos = tmp,						      \
 	      tmp = list_entry ( tmp->member.next, typeof ( *tmp ), member ) )
 
+/**
+ * Test if list contains a specified entry
+ *
+ * @v entry		Entry
+ * @v head		List head
+ * @ret present		List contains specified entry
+ */
+static inline int list_contains ( struct list_head *entry,
+				  struct list_head *head ) {
+	struct list_head *tmp;
+
+	list_for_each ( tmp, head ) {
+		if ( tmp == entry )
+			return 1;
+	}
+	return 0;
+}
+#define list_contains( entry, head ) ( {		\
+	list_check ( (head) );				\
+	list_check ( (entry) );				\
+	list_contains ( (entry), (head) ); } )
+
+/**
+ * Test if list contains a specified entry
+ *
+ * @v entry		Entry
+ * @v head		List head
+ * @ret present		List contains specified entry
+ */
+#define list_contains_entry( entry, head, member )	\
+	list_contains ( &(entry)->member, (head) )
+
 /**
  * Check list contains a specified entry
  *
@@ -219,16 +263,8 @@ static inline int list_empty ( const struct list_head *list ) {
  * @v head		List head
  * @v member		Name of list field within iterator's type
  */
-#define list_check_contains( entry, head, member ) do {		\
-	if ( ASSERTING ) {					\
-		typeof ( entry ) tmp;				\
-		int found = 0;					\
-		list_for_each_entry ( tmp, head, member ) {	\
-			if ( tmp == entry )			\
-				found = 1;			\
-		}						\
-		assert ( found );				\
-	}							\
+#define list_check_contains_entry( entry, head, member ) do {		      \
+	assert ( list_contains_entry ( (entry), (head), member ) );	      \
 	} while ( 0 )
 
 #endif /* _IPXE_LIST_H */
diff --git a/src/net/fc.c b/src/net/fc.c
index 977ad07c..f76cfe92 100644
--- a/src/net/fc.c
+++ b/src/net/fc.c
@@ -1625,7 +1625,7 @@ void fc_ulp_detach ( struct fc_ulp_user *user ) {
 		return;
 
 	/* Sanity checks */
-	list_check_contains ( user, &ulp->users, list );
+	list_check_contains_entry ( user, &ulp->users, list );
 
 	/* Detach user and log out if no users remain */
 	list_del ( &user->list );
diff --git a/src/net/netdevice.c b/src/net/netdevice.c
index f5ec4191..d1ae8af3 100644
--- a/src/net/netdevice.c
+++ b/src/net/netdevice.c
@@ -233,7 +233,7 @@ void netdev_tx_complete_err ( struct net_device *netdev,
 			      struct io_buffer *iobuf, int rc ) {
 
 	/* Catch data corruption as early as possible */
-	list_check_contains ( iobuf, &netdev->tx_queue, list );
+	list_check_contains_entry ( iobuf, &netdev->tx_queue, list );
 
 	/* Dequeue and free I/O buffer */
 	list_del ( &iobuf->list );