diff --git a/fs/bcachefs/mean_and_variance.h b/fs/bcachefs/mean_and_variance.h
index 6dd4c050e78a..647505010b39 100644
--- a/fs/bcachefs/mean_and_variance.h
+++ b/fs/bcachefs/mean_and_variance.h
@@ -4,6 +4,7 @@
 
 #include <linux/types.h>
 #include <linux/limits.h>
+#include <linux/math.h>
 #include <linux/math64.h>
 
 #define SQRT_U64_MAX 4294967295ULL