SUNRPC: Call the default socket callbacks instead of open coding

Rather than code up our own versions of the socket callbacks, just
call the defaults.
This also allows us to merge svc_udp_data_ready() and svc_tcp_data_ready().
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

net/sunrpc/svcsock.c

@@ -60,7 +60,6 @@
 
 static struct svc_sock *svc_setup_socket(struct svc_serv *, struct socket *,
 					 int flags);
-static void		svc_udp_data_ready(struct sock *);
 static int		svc_udp_recvfrom(struct svc_rqst *);
 static int		svc_udp_sendto(struct svc_rqst *);
 static void		svc_sock_detach(struct svc_xprt *);
@@ -398,48 +397,21 @@ static int svc_sock_secure_port(struct svc_rqst *rqstp)
 	return svc_port_is_privileged(svc_addr(rqstp));
 }
 
-static bool sunrpc_waitqueue_active(wait_queue_head_t *wq)
-{
-	if (!wq)
-		return false;
-	/*
-	 * There should normally be a memory * barrier here--see
-	 * wq_has_sleeper().
-	 *
-	 * It appears that isn't currently necessary, though, basically
-	 * because callers all appear to have sufficient memory barriers
-	 * between the time the relevant change is made and the
-	 * time they call these callbacks.
-	 *
-	 * The nfsd code itself doesn't actually explicitly wait on
-	 * these waitqueues, but it may wait on them for example in
-	 * sendpage() or sendmsg() calls.  (And those may be the only
-	 * places, since it it uses nonblocking reads.)
-	 *
-	 * Maybe we should add the memory barriers anyway, but these are
-	 * hot paths so we'd need to be convinced there's no sigificant
-	 * penalty.
-	 */
-	return waitqueue_active(wq);
-}
-
 /*
  * INET callback when data has been received on the socket.
  */
-static void svc_udp_data_ready(struct sock *sk)
+static void svc_data_ready(struct sock *sk)
 {
 	struct svc_sock	*svsk = (struct svc_sock *)sk->sk_user_data;
-	wait_queue_head_t *wq = sk_sleep(sk);
 
 	if (svsk) {
 		dprintk("svc: socket %p(inet %p), busy=%d\n",
 			svsk, sk,
 			test_bit(XPT_BUSY, &svsk->sk_xprt.xpt_flags));
+		svsk->sk_odata(sk);
 		set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
 		svc_xprt_enqueue(&svsk->sk_xprt);
 	}
-	if (sunrpc_waitqueue_active(wq))
-		wake_up_interruptible(wq);
 }
 
 /*
@@ -448,19 +420,13 @@ static void svc_udp_data_ready(struct sock *sk)
 static void svc_write_space(struct sock *sk)
 {
 	struct svc_sock	*svsk = (struct svc_sock *)(sk->sk_user_data);
-	wait_queue_head_t *wq = sk_sleep(sk);
 
 	if (svsk) {
 		dprintk("svc: socket %p(inet %p), write_space busy=%d\n",
 			svsk, sk, test_bit(XPT_BUSY, &svsk->sk_xprt.xpt_flags));
+		svsk->sk_owspace(sk);
 		svc_xprt_enqueue(&svsk->sk_xprt);
 	}
-
-	if (sunrpc_waitqueue_active(wq)) {
-		dprintk("RPC svc_write_space: someone sleeping on %p\n",
-		       svsk);
-		wake_up_interruptible(wq);
-	}
 }
 
 static int svc_tcp_has_wspace(struct svc_xprt *xprt)
@@ -485,11 +451,15 @@ static void svc_tcp_write_space(struct sock *sk)
 	struct svc_sock *svsk = (struct svc_sock *)(sk->sk_user_data);
 	struct socket *sock = sk->sk_socket;
 
+	if (!svsk)
+		return;
+
 	if (!sk_stream_is_writeable(sk) || !sock)
 		return;
-	if (!svsk || svc_tcp_has_wspace(&svsk->sk_xprt))
+	if (svc_tcp_has_wspace(&svsk->sk_xprt)) {
 		clear_bit(SOCK_NOSPACE, &sock->flags);
-	svc_write_space(sk);
+		svc_write_space(sk);
+	}
 }
 
 static void svc_tcp_adjust_wspace(struct svc_xprt *xprt)
@@ -746,7 +716,7 @@ 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_udp_data_ready;
+	svsk->sk_sk->sk_data_ready = svc_data_ready;
 	svsk->sk_sk->sk_write_space = svc_write_space;
 
 	/* initialise setting must have enough space to
@@ -786,11 +756,12 @@ static void svc_udp_init(struct svc_sock *svsk, struct svc_serv *serv)
 static void svc_tcp_listen_data_ready(struct sock *sk)
 {
 	struct svc_sock	*svsk = (struct svc_sock *)sk->sk_user_data;
-	wait_queue_head_t *wq;
 
 	dprintk("svc: socket %p TCP (listen) state change %d\n",
 		sk, sk->sk_state);
 
+	if (svsk)
+		svsk->sk_odata(sk);
 	/*
 	 * This callback may called twice when a new connection
 	 * is established as a child socket inherits everything
@@ -808,10 +779,6 @@ static void svc_tcp_listen_data_ready(struct sock *sk)
 		} else
 			printk("svc: socket %p: no user data\n", sk);
 	}
-
-	wq = sk_sleep(sk);
-	if (sunrpc_waitqueue_active(wq))
-		wake_up_interruptible_all(wq);
 }
 
 /*
@@ -820,7 +787,6 @@ static void svc_tcp_listen_data_ready(struct sock *sk)
 static void svc_tcp_state_change(struct sock *sk)
 {
 	struct svc_sock	*svsk = (struct svc_sock *)sk->sk_user_data;
-	wait_queue_head_t *wq = sk_sleep(sk);
 
 	dprintk("svc: socket %p TCP (connected) state change %d (svsk %p)\n",
 		sk, sk->sk_state, sk->sk_user_data);
@@ -828,26 +794,10 @@ static void svc_tcp_state_change(struct sock *sk)
 	if (!svsk)
 		printk("svc: socket %p: no user data\n", sk);
 	else {
+		svsk->sk_ostate(sk);
 		set_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags);
 		svc_xprt_enqueue(&svsk->sk_xprt);
 	}
-	if (sunrpc_waitqueue_active(wq))
-		wake_up_interruptible_all(wq);
-}
-
-static void svc_tcp_data_ready(struct sock *sk)
-{
-	struct svc_sock *svsk = (struct svc_sock *)sk->sk_user_data;
-	wait_queue_head_t *wq = sk_sleep(sk);
-
-	dprintk("svc: socket %p TCP data ready (svsk %p)\n",
-		sk, sk->sk_user_data);
-	if (svsk) {
-		set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
-		svc_xprt_enqueue(&svsk->sk_xprt);
-	}
-	if (sunrpc_waitqueue_active(wq))
-		wake_up_interruptible(wq);
 }
 
 /*
@@ -901,6 +851,11 @@ static struct svc_xprt *svc_tcp_accept(struct svc_xprt *xprt)
 	dprintk("%s: connect from %s\n", serv->sv_name,
 		__svc_print_addr(sin, buf, sizeof(buf)));
 
+	/* Reset the inherited callbacks before calling svc_setup_socket */
+	newsock->sk->sk_state_change = svsk->sk_ostate;
+	newsock->sk->sk_data_ready = svsk->sk_odata;
+	newsock->sk->sk_write_space = svsk->sk_owspace;
+
 	/* make sure that a write doesn't block forever when
 	 * low on memory
 	 */
@@ -1357,7 +1312,7 @@ static void svc_tcp_init(struct svc_sock *svsk, struct svc_serv *serv)
 	} else {
 		dprintk("setting up TCP socket for reading\n");
 		sk->sk_state_change = svc_tcp_state_change;
-		sk->sk_data_ready = svc_tcp_data_ready;
+		sk->sk_data_ready = svc_data_ready;
 		sk->sk_write_space = svc_tcp_write_space;
 
 		svsk->sk_reclen = 0;
@@ -1606,7 +1561,6 @@ static void svc_sock_detach(struct svc_xprt *xprt)
 {
 	struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
 	struct sock *sk = svsk->sk_sk;
-	wait_queue_head_t *wq;
 
 	dprintk("svc: svc_sock_detach(%p)\n", svsk);
 
@@ -1617,10 +1571,6 @@ static void svc_sock_detach(struct svc_xprt *xprt)
 	sk->sk_write_space = svsk->sk_owspace;
 	sk->sk_user_data = NULL;
 	release_sock(sk);
-
-	wq = sk_sleep(sk);
-	if (sunrpc_waitqueue_active(wq))
-		wake_up_interruptible(wq);
 }
 
 /*