[patch 01/23] scsi: clear garbage after CDBs on SG_IO

[Chris Wright <chrisw@sous-sol.org>]

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-stable review patch.  If anyone has any objections, please let us know.
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From: 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>
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: Chris Wright <chrisw@sous-sol.org>
---

 block/scsi_ioctl.c      |    3 +--
 drivers/scsi/scsi_lib.c |    1 +
 2 files changed, 2 insertions(+), 2 deletions(-)

--- linux-2.6.18.4.orig/block/scsi_ioctl.c
+++ linux-2.6.18.4/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(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;
--- linux-2.6.18.4.orig/drivers/scsi/scsi_lib.c
+++ linux-2.6.18.4/drivers/scsi/scsi_lib.c
@@ -408,6 +408,7 @@ 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;

--