target: Simplify LUN shutdown code

Instead of starting a thread from transport_clear_lun_ref() that
waits for LUN shutdown, wait in that function for LUN shutdown
to finish. Additionally, change the return type of
transport_clear_lun_ref() from int to void.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 965a308..7c0518a 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -2596,31 +2596,10 @@
 }
 EXPORT_SYMBOL(target_wait_for_sess_cmds);
 
-static int transport_clear_lun_ref_thread(void *p)
+void transport_clear_lun_ref(struct se_lun *lun)
 {
-	struct se_lun *lun = p;
-
 	percpu_ref_kill(&lun->lun_ref);
-
 	wait_for_completion(&lun->lun_ref_comp);
-	complete(&lun->lun_shutdown_comp);
-
-	return 0;
-}
-
-int transport_clear_lun_ref(struct se_lun *lun)
-{
-	struct task_struct *kt;
-
-	kt = kthread_run(transport_clear_lun_ref_thread, lun,
-			"tcm_cl_%u", lun->unpacked_lun);
-	if (IS_ERR(kt)) {
-		pr_err("Unable to start clear_lun thread\n");
-		return PTR_ERR(kt);
-	}
-	wait_for_completion(&lun->lun_shutdown_comp);
-
-	return 0;
 }
 
 /**