diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index 55c3237fb1bc..2023d61d5458 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -2570,6 +2570,7 @@ static void do_cciss_request(struct request_queue *q)
 	       (int)creq->nr_sectors);
 #endif				/* CCISS_DEBUG */
 
+	memset(tmp_sg, 0, sizeof(tmp_sg));
 	seg = blk_rq_map_sg(q, creq, tmp_sg);
 
 	/* get the DMA records for the setup */