SUNRPC: Add API to force the client to disconnect

Allow the caller to force a disconnection of the RPC client so that we
can clear any pending requests that are buffered in the socket.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

include/linux/sunrpc/clnt.h

@@ -246,6 +246,7 @@ void rpc_clnt_xprt_switch_remove_xprt(struct rpc_clnt *, struct rpc_xprt *);
 bool rpc_clnt_xprt_switch_has_addr(struct rpc_clnt *clnt,
 			const struct sockaddr *sap);
 void rpc_clnt_xprt_set_online(struct rpc_clnt *clnt, struct rpc_xprt *xprt);
+void rpc_clnt_disconnect(struct rpc_clnt *clnt);
 void rpc_cleanup_clids(void);
 
 static inline int rpc_reply_expected(struct rpc_task *task)

net/sunrpc/clnt.c

@@ -910,6 +910,20 @@ unsigned long rpc_cancel_tasks(struct rpc_clnt *clnt, int error,
 }
 EXPORT_SYMBOL_GPL(rpc_cancel_tasks);
 
+static int rpc_clnt_disconnect_xprt(struct rpc_clnt *clnt,
+				    struct rpc_xprt *xprt, void *dummy)
+{
+	if (xprt_connected(xprt))
+		xprt_force_disconnect(xprt);
+	return 0;
+}
+
+void rpc_clnt_disconnect(struct rpc_clnt *clnt)
+{
+	rpc_clnt_iterate_for_each_xprt(clnt, rpc_clnt_disconnect_xprt, NULL);
+}
+EXPORT_SYMBOL_GPL(rpc_clnt_disconnect);
+
 /*
  * Properly shut down an RPC client, terminating all outstanding
  * requests.