diff --git a/sys/conf/kern.pre.mk b/sys/conf/kern.pre.mk
--- a/sys/conf/kern.pre.mk
+++ b/sys/conf/kern.pre.mk
@@ -297,7 +297,7 @@
 # Infiniband C flags.  Correct include paths and omit errors that linux
 # does not honor.
 OFEDINCLUDES=	-I$S/ofed/include -I$S/ofed/include/uapi ${LINUXKPI_INCLUDES}
-OFEDNOERR=	-Wno-cast-qual -Wno-pointer-arith
+OFEDNOERR=	-Wno-cast-qual -Wno-pointer-arith -Wno-redundant-decls
 OFEDCFLAGS=	${CFLAGS:N-I*} -DCONFIG_INFINIBAND_USER_MEM \
 		${OFEDINCLUDES} ${CFLAGS:M-I*} ${OFEDNOERR}
 OFED_C_NOIMP=	${CC} -c -o ${.TARGET} ${OFEDCFLAGS} ${WERROR}
diff --git a/sys/modules/ibcore/Makefile b/sys/modules/ibcore/Makefile
--- a/sys/modules/ibcore/Makefile
+++ b/sys/modules/ibcore/Makefile
@@ -53,3 +53,5 @@
 CFLAGS+= -DINET6 -DINET -DCONFIG_INFINIBAND_USER_MEM
 
 .include <bsd.kmod.mk>
+
+CWARNFLAGS+= -Wno-cast-qual -Wno-pointer-arith -Wno-redundant-decls