diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
index 99b17cb059..333977aa9f 100644
--- a/linux-user/syscall_defs.h
+++ b/linux-user/syscall_defs.h
@@ -164,9 +164,6 @@ struct target_cmsghdr {
 
 #define TARGET_CMSG_DATA(cmsg) ((unsigned char *) ((struct target_cmsghdr *) (cmsg) + 1))
 #define TARGET_CMSG_NXTHDR(mhdr, cmsg) __target_cmsg_nxthdr (mhdr, cmsg)
-#define TARGET_CMSG_FIRSTHDR(mhdr) \
-  ((size_t) tswapl((mhdr)->msg_controllen) >= sizeof (struct target_cmsghdr) \
-   ? (struct target_cmsghdr *) tswapl((mhdr)->msg_control) : (struct target_cmsghdr *) NULL)
 #define TARGET_CMSG_ALIGN(len) (((len) + sizeof (abi_long) - 1) \
                                & (size_t) ~(sizeof (abi_long) - 1))
 #define TARGET_CMSG_SPACE(len) (TARGET_CMSG_ALIGN (len) \