Factor out waiting for a subreq

src/node.c

@@ -566,6 +566,17 @@ subreq_fixup(struct node *node, struct req *req)
 	return (subreq);
 }
 
+static void
+subreq_wait_done(struct node *node)
+{
+	Lck_Lock(node->subreq.shared_lock);
+	if (node->subreq.done == 0)
+		AZ(Lck_CondWait(
+			   &node->subreq.cond,
+			   node->subreq.shared_lock));
+	Lck_Unlock(node->subreq.shared_lock);
+}
+
 /* ------------------------------------------------------------
  * node cleanup (not holding tree lock)
  *
@@ -714,14 +725,9 @@ push_subreq(struct req *req, struct bytes_tree *tree,
 	assert(node->type == T_SUBREQ);
 	(void) next;
 
-	if (node->subreq.done == 0) {
-		Lck_Lock(node->subreq.shared_lock);
-		if (node->subreq.done == 0)
-			AZ(Lck_CondWait(
-				   &node->subreq.cond,
-				   node->subreq.shared_lock));
-		Lck_Unlock(node->subreq.shared_lock);
-	}
+	if (node->subreq.done == 0)
+		subreq_wait_done(node);
+	AN(node->subreq.done);
 
 	subreq = subreq_fixup(node, req);