diff --git a/block/blk-core.c b/block/blk-core.c
index e6fdb28..5d09f8c 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -117,6 +117,7 @@ void blk_rq_init(struct request_queue *q, struct request *rq)
 	rq->sector = rq->hard_sector = (sector_t) -1;
 	INIT_HLIST_NODE(&rq->hash);
 	RB_CLEAR_NODE(&rq->rb_node);
+	rq->cmd = rq->__cmd;
 	rq->tag = -1;
 	rq->ref_count = 1;
 }
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index d17032c..08df1ea 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -215,8 +215,9 @@ struct request {
 	/*
 	 * when request is used as a packet command carrier
 	 */
-	unsigned int cmd_len;
-	unsigned char cmd[BLK_MAX_CDB];
+	unsigned short cmd_len;
+	unsigned char __cmd[BLK_MAX_CDB];
+	unsigned char *cmd;
 
 	unsigned int data_len;
 	unsigned int extra_len;	/* length of alignment and padding */