SUNRPC: Handle connection reset more efficiently.

If the connection reset is due to an active call on our side, then
the state change is sometimes not reported. Catch those instances
using xs_error_report() instead.
Also remove the xs_tcp_shutdown() call in xs_tcp_send_request() as
the change in behaviour makes it redundant.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

net/sunrpc/xprtsock.c

@@ -718,7 +718,6 @@ static int xs_tcp_send_request(struct rpc_task *task)
 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
 			-status);
 	case -ECONNRESET:
-		xs_tcp_shutdown(xprt);
 	case -ECONNREFUSED:
 	case -ENOTCONN:
 	case -EADDRINUSE:
@@ -774,6 +773,21 @@ static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *s
 	sk->sk_error_report = transport->old_error_report;
 }
 
+static void xs_sock_reset_connection_flags(struct rpc_xprt *xprt)
+{
+	smp_mb__before_atomic();
+	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
+	clear_bit(XPRT_CLOSING, &xprt->state);
+	smp_mb__after_atomic();
+}
+
+static void xs_sock_mark_closed(struct rpc_xprt *xprt)
+{
+	xs_sock_reset_connection_flags(xprt);
+	/* Mark transport as closed and wake up all pending tasks */
+	xprt_disconnect_done(xprt);
+}
+
 /**
  * xs_error_report - callback to handle TCP socket state errors
  * @sk: socket
@@ -793,6 +807,9 @@ static void xs_error_report(struct sock *sk)
 	err = -sk->sk_err;
 	if (err == 0)
 		goto out;
+	/* Is this a reset event? */
+	if (sk->sk_state == TCP_CLOSE)
+		xs_sock_mark_closed(xprt);
 	dprintk("RPC:       xs_error_report client %p, error=%d...\n",
 			xprt, -err);
 	trace_rpc_socket_error(xprt, sk->sk_socket, err);
@@ -801,14 +818,6 @@ static void xs_error_report(struct sock *sk)
 	read_unlock_bh(&sk->sk_callback_lock);
 }
 
-static void xs_sock_reset_connection_flags(struct rpc_xprt *xprt)
-{
-	smp_mb__before_atomic();
-	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
-	clear_bit(XPRT_CLOSING, &xprt->state);
-	smp_mb__after_atomic();
-}
-
 static void xs_reset_transport(struct sock_xprt *transport)
 {
 	struct socket *sock = transport->sock;
@@ -1421,13 +1430,6 @@ static void xs_tcp_data_ready(struct sock *sk)
 	read_unlock_bh(&sk->sk_callback_lock);
 }
 
-static void xs_sock_mark_closed(struct rpc_xprt *xprt)
-{
-	xs_sock_reset_connection_flags(xprt);
-	/* Mark transport as closed and wake up all pending tasks */
-	xprt_disconnect_done(xprt);
-}
-
 /**
  * xs_tcp_state_change - callback to handle TCP socket state changes
  * @sk: socket whose state has changed