From: Bart Van Assche <bart.vanassche@wdc.com>
Date: Fri, 25 Aug 2017 13:46:33 -0700
Subject: [PATCH] scsi: sd: sr: Convert two assignments into warning statements
Git-commit: 0624cbb1e2e64ae4d7d55dc81fc39a0af87a2bd7
Patch-mainline: v4.14-rc1
References: bsc#1118139

Before scsi_prep_fn() calls the ULP .init_command() callback
function it stores the SCSI command pointer in request.special.
This means that the SCpnt = rq->special assignments in the sd
and sr drivers assign a pointer to itself. Hence convert these
two assignment statements into warning statements.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 drivers/scsi/sd.c | 2 +-
 drivers/scsi/sr.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index bea36adeee17..a88639fbedb3 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1013,7 +1013,7 @@ static int sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt)
 	ret = scsi_init_io(SCpnt);
 	if (ret != BLKPREP_OK)
 		goto out;
-	SCpnt = rq->special;
+	WARN_ON_ONCE(SCpnt != rq->special);
 
 	/* from here on until we're complete, any goto out
 	 * is used for a killable error condition */
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index a8f630213a1a..9be34d37c356 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -393,7 +393,7 @@ static int sr_init_command(struct scsi_cmnd *SCpnt)
 	ret = scsi_init_io(SCpnt);
 	if (ret != BLKPREP_OK)
 		goto out;
-	SCpnt = rq->special;
+	WARN_ON_ONCE(SCpnt != rq->special);
 	cd = scsi_cd(rq->rq_disk);
 
 	/* from here on until we're complete, any goto out
-- 
2.12.3