Merge tag 'dm-4.9-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:

 - a couple DM raid and DM mirror fixes

 - a couple .request_fn request-based DM NULL pointer fixes

 - a fix for a DM target reference count leak, on target load error,
   that prevented associated DM target kernel module(s) from being
   removed

* tag 'dm-4.9-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm table: fix missing dm_put_target_type() in dm_table_add_target()
  dm rq: clear kworker_task if kthread_run() returned an error
  dm: free io_barrier after blk_cleanup_queue call
  dm raid: fix activation of existing raid4/10 devices
  dm mirror: use all available legs on multiple failures
  dm mirror: fix read error on recovery after default leg failure
  dm raid: fix compat_features validation

drivers/md/dm-rq.c

@@ -856,8 +856,11 @@ int dm_old_init_request_queue(struct mapped_device *md)
 	kthread_init_worker(&md->kworker);
 	md->kworker_task = kthread_run(kthread_worker_fn, &md->kworker,
 				       "kdmwork-%s", dm_device_name(md));
-	if (IS_ERR(md->kworker_task))
-		return PTR_ERR(md->kworker_task);
+	if (IS_ERR(md->kworker_task)) {
+		int error = PTR_ERR(md->kworker_task);
+		md->kworker_task = NULL;
+		return error;
+	}
 
 	elv_register_queue(md->queue);