diff --git a/lib/raid6/Makefile b/lib/raid6/Makefile
index 0083b5cc646c..d4d56ca6eafc 100644
--- a/lib/raid6/Makefile
+++ b/lib/raid6/Makefile
@@ -48,7 +48,7 @@ endif
 endif
 
 quiet_cmd_unroll = UNROLL  $@
-      cmd_unroll = $(AWK) -f$(srctree)/$(src)/unroll.awk -vN=$* < $< > $@
+      cmd_unroll = $(AWK) -v N=$* -f $(srctree)/$(src)/unroll.awk < $< > $@
 
 targets += int1.c int2.c int4.c int8.c int16.c int32.c
 $(obj)/int%.c: $(src)/int.uc $(src)/unroll.awk FORCE