scsi: sd: Ignore a failure to sync cache due to lack of authorization

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.

Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20190903101840.16483-1-oneukum@suse.com
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/sd.c

@@ -1655,7 +1655,8 @@ static int sd_sync_cache(struct scsi_disk *sdkp, struct scsi_sense_hdr *sshdr)
 		/* 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;