diff --git a/kernel/irq/matrix.c b/kernel/irq/matrix.c
index 6e6d467f3dec57717ffb7cfae9098dedafb02b22..1f0985adf19340fdb9ec02cf9118c035d8f8e346 100644
--- a/kernel/irq/matrix.c
+++ b/kernel/irq/matrix.c
@@ -8,7 +8,7 @@
 #include <linux/cpu.h>
 #include <linux/irq.h>
 
-#define IRQ_MATRIX_SIZE	(BITS_TO_LONGS(IRQ_MATRIX_BITS) * sizeof(unsigned long))
+#define IRQ_MATRIX_SIZE	(BITS_TO_LONGS(IRQ_MATRIX_BITS))
 
 struct cpumap {
 	unsigned int		available;