diff --git a/arch/s390/boot/decompressor.c b/arch/s390/boot/decompressor.c
index e27c2140d620..8dcd7af2911a 100644
--- a/arch/s390/boot/decompressor.c
+++ b/arch/s390/boot/decompressor.c
@@ -23,9 +23,9 @@
 #define memmove memmove
 #define memzero(s, n) memset((s), 0, (n))
 
-#ifdef CONFIG_KERNEL_BZIP2
+#if defined(CONFIG_KERNEL_BZIP2)
 #define BOOT_HEAP_SIZE	0x400000
-#elif CONFIG_KERNEL_ZSTD
+#elif defined(CONFIG_KERNEL_ZSTD)
 #define BOOT_HEAP_SIZE	0x30000
 #else
 #define BOOT_HEAP_SIZE	0x10000