[PATCH v2 3/8] sunrpc: split svc_data_ready into protocol-specific callbacks

[Chuck Lever <cel@kernel.org>]

From: Chuck Lever <chuck.lever@oracle.com>

Separate data-ready callbacks enable protocol-specific
optimizations. UDP and TCP transports already have different
requirements: currently UDP sockets do not implement DTLS, so the
XPT_HANDSHAKE check is unnecessary overhead for them.

Prepare the server-side socket infrastructure for additional
changes to TCP's data_ready callback.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 include/trace/events/sunrpc.h |  3 ++-
 net/sunrpc/svcsock.c          | 39 +++++++++++++++++++++++++++++------
 2 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index 076182ae19ec..c5a15b7a321d 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -2313,7 +2313,8 @@ DEFINE_SVCSOCK_EVENT(tcp_send);
 DEFINE_SVCSOCK_EVENT(tcp_recv);
 DEFINE_SVCSOCK_EVENT(tcp_recv_eagain);
 DEFINE_SVCSOCK_EVENT(tcp_recv_err);
-DEFINE_SVCSOCK_EVENT(data_ready);
+DEFINE_SVCSOCK_EVENT(udp_data_ready);
+DEFINE_SVCSOCK_EVENT(tcp_data_ready);
 DEFINE_SVCSOCK_EVENT(write_space);
 
 TRACE_EVENT(svcsock_tcp_recv_short,
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index d61cd9b40491..73644f3b63c7 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -397,10 +397,14 @@ static void svc_sock_secure_port(struct svc_rqst *rqstp)
 		clear_bit(RQ_SECURE, &rqstp->rq_flags);
 }
 
-/*
- * INET callback when data has been received on the socket.
+/**
+ * svc_udp_data_ready - sk->sk_data_ready callback for UDP sockets
+ * @sk: socket whose receive buffer contains data
+ *
+ * This implementation does not yet support DTLS, so the
+ * XPT_HANDSHAKE check is not needed here.
  */
-static void svc_data_ready(struct sock *sk)
+static void svc_udp_data_ready(struct sock *sk)
 {
 	struct svc_sock	*svsk = (struct svc_sock *)sk->sk_user_data;
 
@@ -410,7 +414,30 @@ static void svc_data_ready(struct sock *sk)
 		/* Refer to svc_setup_socket() for details. */
 		rmb();
 		svsk->sk_odata(sk);
-		trace_svcsock_data_ready(&svsk->sk_xprt, 0);
+		trace_svcsock_udp_data_ready(&svsk->sk_xprt, 0);
+		if (!test_and_set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags))
+			svc_xprt_enqueue(&svsk->sk_xprt);
+	}
+}
+
+/**
+ * svc_tcp_data_ready - sk->sk_data_ready callback for TCP sockets
+ * @sk: socket whose receive buffer contains data
+ *
+ * Data ingest is skipped while a TLS handshake is in progress
+ * (XPT_HANDSHAKE).
+ */
+static void svc_tcp_data_ready(struct sock *sk)
+{
+	struct svc_sock	*svsk = (struct svc_sock *)sk->sk_user_data;
+
+	trace_sk_data_ready(sk);
+
+	if (svsk) {
+		/* Refer to svc_setup_socket() for details. */
+		rmb();
+		svsk->sk_odata(sk);
+		trace_svcsock_tcp_data_ready(&svsk->sk_xprt, 0);
 		if (test_bit(XPT_HANDSHAKE, &svsk->sk_xprt.xpt_flags))
 			return;
 		if (!test_and_set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags))
@@ -835,7 +862,7 @@ static void svc_udp_init(struct svc_sock *svsk, struct svc_serv *serv)
 	svc_xprt_init(sock_net(svsk->sk_sock->sk), &svc_udp_class,
 		      &svsk->sk_xprt, serv);
 	clear_bit(XPT_CACHE_AUTH, &svsk->sk_xprt.xpt_flags);
-	svsk->sk_sk->sk_data_ready = svc_data_ready;
+	svsk->sk_sk->sk_data_ready = svc_udp_data_ready;
 	svsk->sk_sk->sk_write_space = svc_write_space;
 
 	/* initialise setting must have enough space to
@@ -1368,7 +1395,7 @@ static void svc_tcp_init(struct svc_sock *svsk, struct svc_serv *serv)
 		set_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags);
 	} else {
 		sk->sk_state_change = svc_tcp_state_change;
-		sk->sk_data_ready = svc_data_ready;
+		sk->sk_data_ready = svc_tcp_data_ready;
 		sk->sk_write_space = svc_write_space;
 
 		svsk->sk_marker = xdr_zero;
-- 
2.52.0