From: David Milburn <dmilburn@redhat.com>
Date: Tue, 19 Jan 2010 20:27:45 -0500
Subject: [scsi] stex: don't try to scan a nonexistent lun
Message-id: <20100119202745.GB4160@dhcp-210.hsv.redhat.com>
Patchwork-id: 22655
O-Subject: [RHEL5.5 PATCH] stex: fix inconsistent usage of max_lun
Bugzilla: 531488
RH-Acked-by: Jeff Garzik <jgarzik@redhat.com>
RH-Acked-by: Tomas Henzl <thenzl@redhat.com>

This patch is from Ed Lin at Promise, it replaces the
previous patch to fix manually scanning a non-existent
LUN. Here is the original RHEL5.5 post and the post
to revert due to upstream regressions.

http://post-office.corp.redhat.com/archives/rhkernel-list/2009-November/msg00594.html
http://post-office.corp.redhat.com/archives/rhkernel-list/2009-December/msg00520.html

This patch is a replacement which only effects stex.c, it is a
backport of upstream commit:

commit 91e6ecada757a6e2ef7b937634af8a04376772a1
Author: Ed Lin <ed.lin@promise.com>
Date:   Fri Dec 18 17:34:51 2009 -0800

    [SCSI] stex: fix scan of nonexistent lun

    During a manual scan, a user can send command to a nonexistent
    lun, precisely at the point of max_lun. Normally it's possible
    (but not required) that the firmware has the knowledge that it
    is an invalid lun. In the particular case when max_lun is 256,
    however, the nonexistent lun 256 will be confused with lun 0,
    because the lun member in a request message is only u8, and 256
    will become 0. So we need to fix the problem, at least, at the
    driver level.

Customer has verified a -183.el5 test kernel built with this
patch, it resolves BZ 531488, please review and ACK.

Thanks,
David

 drivers/scsi/stex.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

Signed-off-by: Jarod Wilson <jarod@redhat.com>

diff --git a/drivers/scsi/stex.c b/drivers/scsi/stex.c
index 46105d0..cce3329 100644
--- a/drivers/scsi/stex.c
+++ b/drivers/scsi/stex.c
@@ -722,6 +722,11 @@ stex_queuecommand(struct scsi_cmnd *cmd, void (* done)(struct scsi_cmnd *))
 		}
 		break;
 	case INQUIRY:
+		if (lun >= host->max_lun) {
+			cmd->result = DID_NO_CONNECT << 16;
+			done(cmd);
+			return 0;
+		}
 		if (id != host->max_id - 1)
 			break;
 		if (!lun && !cmd->device->channel &&