diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 91dfb75..95de239 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -129,6 +129,7 @@
 	BLK_MQ_F_SHOULD_MERGE	= 1 << 0,
 	BLK_MQ_F_SHOULD_SORT	= 1 << 1,
 	BLK_MQ_F_TAG_SHARED	= 1 << 2,
+	BLK_MQ_F_SG_MERGE	= 1 << 3,
 
 	BLK_MQ_S_STOPPED	= 0,
 	BLK_MQ_S_TAG_ACTIVE	= 1,