SUNRPC: Handle EADDRINUSE on connect

Now that we're setting SO_REUSEPORT, we still need to handle the
case where a connect() is attempted, but the old socket is still
lingering.
Essentially, all we want to do here is handle the error by waiting
a few seconds and then retrying.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

net/sunrpc/clnt.c

@@ -1826,6 +1826,7 @@ call_connect_status(struct rpc_task *task)
 	case -ECONNABORTED:
 	case -ENETUNREACH:
 	case -EHOSTUNREACH:
+	case -EADDRINUSE:
 	case -ENOBUFS:
 	case -EPIPE:
 		if (RPC_IS_SOFTCONN(task))
@@ -1934,6 +1935,7 @@ call_transmit_status(struct rpc_task *task)
 		}
 	case -ECONNRESET:
 	case -ECONNABORTED:
+	case -EADDRINUSE:
 	case -ENOTCONN:
 	case -ENOBUFS:
 	case -EPIPE:
@@ -2053,6 +2055,7 @@ call_status(struct rpc_task *task)
 	case -ECONNRESET:
 	case -ECONNABORTED:
 		rpc_force_rebind(clnt);
+	case -EADDRINUSE:
 	case -ENOBUFS:
 		rpc_delay(task, 3*HZ);
 	case -EPIPE:

net/sunrpc/xprtsock.c

@@ -721,6 +721,7 @@ static int xs_tcp_send_request(struct rpc_task *task)
 		xs_tcp_shutdown(xprt);
 	case -ECONNREFUSED:
 	case -ENOTCONN:
+	case -EADDRINUSE:
 	case -EPIPE:
 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
 	}
@@ -2299,6 +2300,7 @@ static void xs_tcp_setup_socket(struct work_struct *work)
 	case -ECONNREFUSED:
 	case -ECONNRESET:
 	case -ENETUNREACH:
+	case -EADDRINUSE:
 	case -ENOBUFS:
 		/* retry with existing socket, after a delay */
 		goto out;