From: Jesse Larrew <jlarrew@redhat.com>
Date: Thu, 14 May 2009 00:59:50 -0400
Subject: [scsi] handle unit attention in mode select
Message-id: 20090514045659.10947.86740.sendpatchset@squad5-lp1.lab.bos.redhat.com
O-Subject: [PATCH RHEL5.4 3/10 BZ489582] Handle unit attention in mode select
Bugzilla: 489582
RH-Acked-by: Mike Christie <mchristi@redhat.com>

RHBZ#:
======
https://bugzilla.redhat.com/show_bug.cgi?id=489582

Description:
===========
This is a bug fix for all archs.

This patch is to add retry logic if the mode select command is returned with
sense NO_SENSE, UNIT_ATTENTION, ABORTED_COMMAND, or NOT_READY(02/04/01).
This patch reorganises the sense keys from if-else to switch-case format
for better maintainability.

RHEL Version Found:
================
RHEL 5.3

kABI Status:
============
No symbols were harmed.

Brew:
=====
Built on all platforms.
http://brewweb.devel.redhat.com/brew/taskinfo?taskID=1794596

Upstream Status:
================
commit: 7687fb9209422d35334995b8ace38de92e595d16

Test Status:
============
This patch was tested by Chandra Seetharaman at IBM
(sekharan@us.ibm.com).

===============================================================

Jesse Larrew
IBM Onsite Partner
978-392-3183
jlarrew@redhat.com

Proposed Patch:
===============
This patch is based on 2.6.18-136.el5.

diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c
index 89ac8b2..5d4ad1d 100644
--- a/drivers/scsi/device_handler/scsi_dh_rdac.c
+++ b/drivers/scsi/device_handler/scsi_dh_rdac.c
@@ -452,28 +452,40 @@ static int mode_select_handle_sense(struct scsi_device *sdev,
 				    unsigned char *sensebuf)
 {
 	struct scsi_sense_hdr sense_hdr;
-	int sense, err = SCSI_DH_IO, ret;
+	int err = SCSI_DH_IO, ret;
 
 	ret = scsi_normalize_sense(sensebuf, SCSI_SENSE_BUFFERSIZE, &sense_hdr);
 	if (!ret)
 		goto done;
 
 	err = SCSI_DH_OK;
-	sense = (sense_hdr.sense_key << 16) | (sense_hdr.asc << 8) |
-			sense_hdr.ascq;
-	/* If it is retryable failure, submit the c9 inquiry again */
-	if (sense == 0x59136 || sense == 0x68b02 || sense == 0xb8b02 ||
-			    sense == 0x62900) {
-		/* 0x59136    - Command lock contention
-		 * 0x[6b]8b02 - Quiesense in progress or achieved
-		 * 0x62900    - Power On, Reset, or Bus Device Reset
-		 */
+
+	switch (sense_hdr.sense_key) {
+	case NO_SENSE:
+	case ABORTED_COMMAND:
+	case UNIT_ATTENTION:
 		err = SCSI_DH_RETRY;
+		break;
+	case NOT_READY:
+		if (sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x01)
+			/* LUN Not Ready and is in the Process of Becoming
+			 * Ready
+			 */
+			err = SCSI_DH_RETRY;
+		break;
+	case ILLEGAL_REQUEST:
+		if (sense_hdr.asc == 0x91 && sense_hdr.ascq == 0x36)
+			/*
+			 * Command Lock contention
+			 */
+			err = SCSI_DH_RETRY;
+		break;
+	default:
+		sdev_printk(KERN_INFO, sdev,
+			    "MODE_SELECT failed with sense %02x/%02x/%02x.\n",
+			    sense_hdr.sense_key, sense_hdr.asc, sense_hdr.ascq);
 	}
 
-	if (sense)
-		sdev_printk(KERN_INFO, sdev,
-			"MODE_SELECT failed with sense 0x%x.\n", sense);
 done:
 	return err;
 }