Commit 
a7a20d1 "[SCSI] sd: limit the scope of the async probe domain"
moved sd probe work out of reach of wait_for_device_probe().  Allow it
to be synced via scsi_complete_async_scans().
Reported-by: Meelis Roos <mroos@linux.ee>
Tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
 
        do {
                if (list_empty(&scanning_hosts))
-                       return 0;
+                       goto out;
                /* If we can't get memory immediately, that's OK.  Just
                 * sleep a little.  Even if we never get memory, the async
                 * scans will finish eventually.
        }
  done:
        spin_unlock(&async_scan_lock);
-
        kfree(data);
+
+ out:
+       async_synchronize_full_domain(&scsi_sd_probe_domain);
+
        return 0;
 }