};
 // module_param_string_array(vendor_labels, NULL, 0444);
 
+#define ch_printk(prefix, ch, fmt, a...) \
+       sdev_printk(prefix, (ch)->device, "[%s] " fmt, \
+                   (ch)->name, ##a)
+
 #define DPRINTK(fmt, arg...)                                           \
 do {                                                                   \
        if (debug)                                                      \
-               printk(KERN_DEBUG "%s: " fmt, ch->name, ##arg);         \
+               ch_printk(KERN_DEBUG, ch, fmt, ##arg);                  \
 } while (0)
 #define VPRINTK(level, fmt, arg...)                                    \
 do {                                                                   \
        if (verbose)                                                    \
-               printk(level "%s: " fmt, ch->name, ##arg);              \
+               ch_printk(level, ch, fmt, ##arg);                       \
 } while (0)
 
 /* ------------------------------------------------------------------- */
                __scsi_print_command(cmd);
        }
 
-        result = scsi_execute_req(ch->device, cmd, direction, buffer,
+       result = scsi_execute_req(ch->device, cmd, direction, buffer,
                                  buflength, &sshdr, timeout * HZ,
                                  MAX_RETRIES, NULL);
 
                                  MKDEV(SCSI_CHANGER_MAJOR, ch->minor), ch,
                                  "s%s", ch->name);
        if (IS_ERR(class_dev)) {
-               printk(KERN_WARNING "ch%d: device_create failed\n",
-                      ch->minor);
+               sdev_printk(KERN_WARNING, sd, "ch%d: device_create failed\n",
+                           ch->minor);
                ret = PTR_ERR(class_dev);
                goto remove_idr;
        }