DLPX-83697 iscsi target login should wait until tx/rx threads have properly started

drivers/target/iscsi/iscsi_target.c

@@ -3813,6 +3813,7 @@ int iscsi_target_tx_thread(void *arg)
 	 * connection recovery / failure event can be triggered externally.
 	 */
 	allow_signal(SIGINT);
+	complete(&conn->kthr_start_comp);
 
 	while (!kthread_should_stop()) {
 		/*
@@ -4041,6 +4042,7 @@ int iscsi_target_rx_thread(void *arg)
 	 * connection recovery / failure event can be triggered externally.
 	 */
 	allow_signal(SIGINT);
+	complete(&conn->kthr_start_comp);
 	/*
 	 * Wait for iscsi_post_login_handler() to complete before allowing
 	 * incoming iscsi/tcp socket I/O, and/or failing the connection.

drivers/target/iscsi/iscsi_target_login.c

@@ -646,6 +646,7 @@ int iscsit_start_kthreads(struct iscsi_conn *conn)
 		ret = PTR_ERR(conn->tx_thread);
 		goto out_bitmap;
 	}
+	wait_for_completion(&conn->kthr_start_comp);
 	conn->tx_thread_active = true;
 
 	conn->rx_thread = kthread_run(iscsi_target_rx_thread, conn,
@@ -655,6 +656,7 @@ int iscsit_start_kthreads(struct iscsi_conn *conn)
 		ret = PTR_ERR(conn->rx_thread);
 		goto out_tx;
 	}
+	wait_for_completion(&conn->kthr_start_comp);
 	conn->rx_thread_active = true;
 
 	return 0;
@@ -1127,6 +1129,7 @@ static struct iscsi_conn *iscsit_alloc_conn(struct iscsi_np *np)
 	init_completion(&conn->rx_half_close_comp);
 	init_completion(&conn->tx_half_close_comp);
 	init_completion(&conn->rx_login_comp);
+	init_completion(&conn->kthr_start_comp);
 	spin_lock_init(&conn->cmd_lock);
 	spin_lock_init(&conn->conn_usage_lock);
 	spin_lock_init(&conn->immed_queue_lock);

include/target/iscsi/iscsi_target_core.h

@@ -562,6 +562,7 @@ struct iscsi_conn {
 	struct completion	conn_logout_comp;
 	struct completion	tx_half_close_comp;
 	struct completion	rx_half_close_comp;
+	struct completion	kthr_start_comp;
 	/* socket used by this connection */
 	struct socket		*sock;
 	void			(*orig_data_ready)(struct sock *);