[PATCH 3.16 006/136] scsi: sd: Ignore a failure to sync cache due to lack of authorization

[Ben Hutchings]

3.16.80-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Oliver Neukum <oneukum@xxxxxxxx>

commit 21e3d6c81179bbdfa279efc8de456c34b814cfd2 upstream.

I've got a report about a UAS drive enclosure reporting back Sense: Logical
unit access not authorized if the drive it holds is password protected.
While the drive is obviously unusable in that state as a mass storage
device, it still exists as a sd device and when the system is asked to
perform a suspend of the drive, it will be sent a SYNCHRONIZE CACHE. If
that fails due to password protection, the error must be ignored.

Link: https://lore.kernel.org/r/20190903101840.16483-1-oneukum@xxxxxxxx
Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
[bwh: Backported to 3.16: sshdr is a struct not a pointer here]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/scsi/sd.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1470,7 +1470,8 @@ static int sd_sync_cache(struct scsi_dis
 		/* we need to evaluate the error return  */
 		if (scsi_sense_valid(&sshdr) &&
 			(sshdr.asc == 0x3a ||	/* medium not present */
-			 sshdr.asc == 0x20))	/* invalid command */
+			 sshdr.asc == 0x20 ||	/* invalid command */
+			 (sshdr.asc == 0x74 && sshdr.ascq == 0x71)))	/* drive is password locked */
 				/* this is no error here */
 				return 0;