diff --git a/include/linux/raid/pq.h b/include/linux/raid/pq.h
index 2b59cc824395..53272e9860a7 100644
--- a/include/linux/raid/pq.h
+++ b/include/linux/raid/pq.h
@@ -132,7 +132,7 @@ void raid6_dual_recov(int disks, size_t bytes, int faila, int failb,
 						     PROT_READ|PROT_WRITE,   \
 						     MAP_PRIVATE|MAP_ANONYMOUS,\
 						     0, 0))
-# define free_pages(x, y)	munmap((void *)(x), (y)*PAGE_SIZE)
+# define free_pages(x, y)	munmap((void *)(x), PAGE_SIZE << (y))
 
 static inline void cpu_relax(void)
 {