From: Tejun Heo <htejun@gmail.com>
Date: Thu, 16 Nov 2006 09:19:31 +0000 (-0800)
Subject: [PATCH] scsi: clear garbage after CDBs on SG_IO
X-Git-Tag: v2.6.19~89
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=097b8457dafe7efc22201b4062e2d1e82e494067;p=linux-2.6

[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 a19338e621..e55a756214 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -286,9 +286,8 @@ static int sg_io(struct file *file, request_queue_t *q,
 	 * 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 d2c02df12f..3ac4890ce0 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -410,6 +410,7 @@ int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd,
 		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;