diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index ef42bb2b12b6dd89b0edc1734485e66147920759..11e4235d0b0c8e984adc507a80657382640db248 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -256,6 +256,7 @@ static void rq_init(request_queue_t *q, struct request *rq)
 	rq->end_io = NULL;
 	rq->end_io_data = NULL;
 	rq->completion_data = NULL;
+	rq->next_rq = NULL;
 }
 
 /**
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 24b474e05a4457ffe6fa518d706d40a24921db13..b32564a1e105c4220d14d988e6530a141b46be76 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -317,6 +317,9 @@ struct request {
 	 */
 	rq_end_io_fn *end_io;
 	void *end_io_data;
+
+	/* for bidi */
+	struct request *next_rq;
 };
 
 /*
@@ -486,6 +489,7 @@ struct request_queue
 #define QUEUE_FLAG_REENTER	6	/* Re-entrancy avoidance */
 #define QUEUE_FLAG_PLUGGED	7	/* queue is plugged */
 #define QUEUE_FLAG_ELVSWITCH	8	/* don't use elevator, just do FIFO */
+#define QUEUE_FLAG_BIDI		9	/* queue supports bidi requests */
 
 enum {
 	/*
@@ -550,6 +554,7 @@ enum {
 #define blk_sorted_rq(rq)	((rq)->cmd_flags & REQ_SORTED)
 #define blk_barrier_rq(rq)	((rq)->cmd_flags & REQ_HARDBARRIER)
 #define blk_fua_rq(rq)		((rq)->cmd_flags & REQ_FUA)
+#define blk_bidi_rq(rq)		((rq)->next_rq != NULL)
 
 #define list_entry_rq(ptr)	list_entry((ptr), struct request, queuelist)