diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index b7ee9c34dbd678fc984db3295a70c117ee2fc2f2..d41edd28298b68ff335e6324df7e4e793a481d93 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -276,7 +276,7 @@ struct zs_pool {
 struct zspage {
 	struct {
 		unsigned int fullness:FULLNESS_BITS;
-		unsigned int class:CLASS_BITS;
+		unsigned int class:CLASS_BITS + 1;
 		unsigned int isolated:ISOLATED_BITS;
 		unsigned int magic:MAGIC_VAL_BITS;
 	};