--- block.c
+++ block.c
@@ -54,7 +54,7 @@
 #ifndef BLKTRACESTART
 #define BLKTRACESTART _IO(0x12,116)
 #endif
-#ifndef BLKTRACESTART
+#ifndef BLKTRACESTOP
 #define BLKTRACESTOP _IO(0x12,117)
 #endif
 #ifndef BLKTRACETEARDOWN