From: Tom Coughlan <coughlan@redhat.com>
Date: Fri, 5 Dec 2008 16:10:17 -0500
Subject: [scsi] fix error handler to call scsi_decide_disposition
Message-id: 1228511417.30284.109.camel@p670.boston.redhat.com
O-Subject: [RHEL5.3 PATCH] fix scsi error handler to call scsi_decide_disposition
Bugzilla: 474345
RH-Acked-by: Peter Martuccelli <peterm@redhat.com>
RH-Acked-by: Mike Christie <mchristi@redhat.com>
RH-Acked-by: Rob Evers <revers@redhat.com>

The interface of scsi_decide_disposition() was changed in
linux-2.6-scsi-modify-failfast-so-it-does-not-always-fail-fast.patch.

The scsi_decide_disposition() is called from scsi_softirq_done() and
scsi_eh_get_sense().  scsi_softirq_done() was modified to match the new
interface. However, the new interface support is missing in scsi_eh_get_sense().

This change will cause an unnecessary SCSI bus reset.  This is because
if a SCSI command to the SCSI device fails, SCSI middle layer queues
the failed command to the EH queue and wakes up the error handler, but
the error handler of SCSI middle layer calls "request sense" SCSI
command in scsi_eh_get_sense(), which will fail because of the above change.

When a SAS tape device is connected to MegaRAID SAS HBA controlled by
megaraid_sas driver, the status of the tape device under the SCSI bus
cannot be retrieved through mt command because mt command fails after
the bus reset caused by the above problem, and the tape drive
will no longer be usable.

The interface change is newly introduced in RHEL5.3 beta, so this case
is a regression.

Resolves Bug 474345

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 918ec68..b769b29 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -840,13 +840,13 @@ int scsi_eh_get_sense(struct list_head *work_q,
 		 * if the result was normal, then just pass it along to the
 		 * upper level.
 		 */
-		if (rtn == SUCCESS)
+		if (scsi_disposition_finish(rtn))
 			/* we don't want this command reissued, just
 			 * finished with the sense data, so set
 			 * retries to the max allowed to ensure it
 			 * won't get reissued */
 			scmd->retries = scmd->allowed;
-		else if (rtn != NEEDS_RETRY)
+		else if (!scsi_disposition_retry(rtn))
 			continue;
 
 		scsi_eh_finish_cmd(scmd, done_q);