From 919f797a4c9c22ff5ec059744dba364dc600ece2 Mon Sep 17 00:00:00 2001
From: "Martin K. Petersen" <martin.petersen@oracle.com>
Date: Sat, 14 Apr 2012 23:01:28 -0400
Subject: SCSI: Fix error handling when no ULD is attached
Commit 18a4d0a22ed6 ("[SCSI] Handle disk devices which can not process
medium access commands") introduced a bug in which we would attempt to
dereference the scsi driver even when the device had no ULD attached.
Ensure that a driver is registered and make the driver accessor function
more resilient to errors during device discovery.
Reported-by: Elric Fu <elricfu1@gmail.com>
Reported-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
drivers/scsi/scsi_error.c | 2 +-
include/scsi/scsi_cmnd.h | 3 +++
2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 2cfcbffa41fd..386f0c53bea7 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -835,7 +835,7 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
scsi_eh_restore_cmnd(scmd, &ses);
- if (sdrv->eh_action)
+ if (sdrv && sdrv->eh_action)
rtn = sdrv->eh_action(scmd, cmnd, cmnd_size, rtn);
return rtn;
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index 377df4a28512..1e1198546c72 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -134,6 +134,9 @@ struct scsi_cmnd {
static inline struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
{
+ if (!cmd->request->rq_disk)
+ return NULL;
+
return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
}
--
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