diff --git a/sys/fs/nullfs/null_vnops.c b/sys/fs/nullfs/null_vnops.c
--- a/sys/fs/nullfs/null_vnops.c
+++ b/sys/fs/nullfs/null_vnops.c
@@ -528,7 +528,7 @@
 		}
 	}
 
-	return (null_bypass((struct vop_generic_args *)ap));
+	return (null_bypass(&ap->a_gen));
 }
 
 /*
@@ -539,7 +539,7 @@
 {
 	int error;
 
-	if ((error = null_bypass((struct vop_generic_args *)ap)) != 0)
+	if ((error = null_bypass(&ap->a_gen)) != 0)
 		return (error);
 
 	ap->a_sb->st_dev = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
@@ -551,7 +551,7 @@
 {
 	int error;
 
-	if ((error = null_bypass((struct vop_generic_args *)ap)) != 0)
+	if ((error = null_bypass(&ap->a_gen)) != 0)
 		return (error);
 
 	ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
@@ -584,7 +584,7 @@
 			break;
 		}
 	}
-	return (null_bypass((struct vop_generic_args *)ap));
+	return (null_bypass(&ap->a_gen));
 }
 
 static int
@@ -610,7 +610,7 @@
 			break;
 		}
 	}
-	return (null_bypass((struct vop_generic_args *)ap));
+	return (null_bypass(&ap->a_gen));
 }
 
 /*