[PATCH] scsi: clear garbage after CDBs on SG_IO

ATAPI devices transfer fixed number of bytes for CDBs (12 or 16).  Some
ATAPI devices choke when shorter CDB is used and the left bytes contain
garbage.  Block SG_IO cleared left bytes but SCSI SG_IO didn't.  This patch
makes SCSI SG_IO clear it and simplify CDB clearing in block SG_IO.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Mathieu Fluhr <mfluhr@nero.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Douglas Gilbert <dougg@torque.net>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: <stable@kernel.org>
Acked-by: Jeff Garzik <jgarzik@pobox.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index a19338e..e55a756 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -286,9 +286,8 @@
 	 * fill in request structure
 	 */
 	rq->cmd_len = hdr->cmd_len;
+	memset(rq->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */
 	memcpy(rq->cmd, cmd, hdr->cmd_len);
-	if (sizeof(rq->cmd) != hdr->cmd_len)
-		memset(rq->cmd + hdr->cmd_len, 0, sizeof(rq->cmd) - hdr->cmd_len);
 
 	memset(sense, 0, sizeof(sense));
 	rq->sense = sense;
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index d2c02df..3ac4890 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -410,6 +410,7 @@
 		goto free_req;
 
 	req->cmd_len = cmd_len;
+	memset(req->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */
 	memcpy(req->cmd, cmd, req->cmd_len);
 	req->sense = sioc->sense;
 	req->sense_len = 0;