diff --git a/src/unix/notbsd/linux/s390x.rs b/src/unix/notbsd/linux/s390x.rs
index 9196f88b..9e3814f3 100644
--- a/src/unix/notbsd/linux/s390x.rs
+++ b/src/unix/notbsd/linux/s390x.rs
@@ -791,6 +791,9 @@ pub const MAP_HUGETLB: ::c_int = 0x040000;
 
 pub const EFD_NONBLOCK: ::c_int = 0x800;
 
+pub const F_RDLCK: ::c_int = 0;
+pub const F_WRLCK: ::c_int = 1;
+pub const F_UNLCK: ::c_int = 2;
 pub const F_GETLK: ::c_int = 5;
 pub const F_GETOWN: ::c_int = 9;
 pub const F_SETOWN: ::c_int = 8;