[PATCH] clear garbage after CDBs on SG_IO

[Tejun Heo <htejun@gmail.com>]

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>

diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index 2dc3264..cac7f18 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -286,9 +286,8 @@ static int sg_io(struct file *file, requ
 	 * fill in request structure
 	 */
 	rq->cmd_len = hdr->cmd_len;
+	memset(req->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 @@ int scsi_execute_async(struct scsi_devic
 		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;