SUNRPC add function to offline remove trunkable transports

Iterate thru available transports in the xprt_switch for all
trunkable transports offline and possibly remote them as well.
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

include/linux/sunrpc/clnt.h

@@ -234,6 +234,7 @@ int		rpc_clnt_setup_test_and_add_xprt(struct rpc_clnt *,
 			struct rpc_xprt_switch *,
 			struct rpc_xprt *,
 			void *);
+void		rpc_clnt_manage_trunked_xprts(struct rpc_clnt *);
 
 const char *rpc_proc_name(const struct rpc_task *task);
 

net/sunrpc/clnt.c

@@ -3000,6 +3000,52 @@ int rpc_clnt_add_xprt(struct rpc_clnt *clnt,
 }
 EXPORT_SYMBOL_GPL(rpc_clnt_add_xprt);
 
+static int rpc_xprt_offline(struct rpc_clnt *clnt,
+			    struct rpc_xprt *xprt,
+			    void *data)
+{
+	struct rpc_xprt *main_xprt;
+	struct rpc_xprt_switch *xps;
+	int err = 0;
+
+	xprt_get(xprt);
+
+	rcu_read_lock();
+	main_xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
+	xps = xprt_switch_get(rcu_dereference(clnt->cl_xpi.xpi_xpswitch));
+	err = rpc_cmp_addr_port((struct sockaddr *)&xprt->addr,
+				(struct sockaddr *)&main_xprt->addr);
+	rcu_read_unlock();
+	xprt_put(main_xprt);
+	if (err)
+		goto out;
+
+	if (wait_on_bit_lock(&xprt->state, XPRT_LOCKED, TASK_KILLABLE)) {
+		err = -EINTR;
+		goto out;
+	}
+	xprt_set_offline_locked(xprt, xps);
+
+	xprt_release_write(xprt, NULL);
+out:
+	xprt_put(xprt);
+	xprt_switch_put(xps);
+	return err;
+}
+
+/* rpc_clnt_manage_trunked_xprts -- offline trunked transports
+ * @clnt rpc_clnt structure
+ *
+ * For each active transport found in the rpc_clnt structure call
+ * the function rpc_xprt_offline() which will identify trunked transports
+ * and will mark them offline.
+ */
+void rpc_clnt_manage_trunked_xprts(struct rpc_clnt *clnt)
+{
+	rpc_clnt_iterate_for_each_xprt(clnt, rpc_xprt_offline, NULL);
+}
+EXPORT_SYMBOL_GPL(rpc_clnt_manage_trunked_xprts);
+
 struct connect_timeout_data {
 	unsigned long connect_timeout;
 	unsigned long reconnect_timeout;