scsi: only re-lock door after EH on devices that were reset

Setups that use the blk-mq I/O path can lock up if a host with a single
device that has its door locked enters EH.  Make sure to only send the
command to re-lock the door to devices that actually were reset and thus
might have lost their state.  Otherwise the EH code might be get blocked
on blk_get_request as all requests for non-reset devices might be in use.

Cc: stable@vger.kernel.org
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reported-by: NMeelis Roos <meelis.roos@ut.ee>
Tested-by: NMeelis Roos <meelis.roos@ut.ee>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/scsi_error.c

@@ -2001,8 +2001,10 @@ static void scsi_restart_operations(struct Scsi_Host *shost)
 	 * is no point trying to lock the door of an off-line device.
 	 */
 	shost_for_each_device(sdev, shost) {
-		if (scsi_device_online(sdev) && sdev->locked)
+		if (scsi_device_online(sdev) && sdev->was_reset && sdev->locked) {
 			scsi_eh_lock_door(sdev);
+			sdev->was_reset = 0;
+		}
 	}
 
 	/*