diff --git a/scst/include/scst.h b/scst/include/scst.h
index e1255de59..339c32934 100644
--- a/scst/include/scst.h
+++ b/scst/include/scst.h
@@ -81,10 +81,14 @@ typedef _Bool bool;
 #define false 0
 #endif
 
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 21) && !defined(RHEL_MAJOR)
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 21)
+#ifndef __packed
 #define __packed __attribute__((packed))
+#endif
+#ifndef __aligned
 #define __aligned __attribute__((aligned))
 #endif
+#endif
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 22)
 char *kvasprintf(gfp_t gfp, const char *fmt, va_list ap);