1 files changed, 32 insertions, 8 deletions

diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 0c8120229..1413cdcc1 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -181,7 +181,7 @@ int svc_send_common(struct socket *sock, struct xdr_buf *xdr,
 	struct page	**ppage = xdr->pages;
 	size_t		base = xdr->page_base;
 	unsigned int	pglen = xdr->page_len;
-	unsigned int	flags = MSG_MORE;
+	unsigned int	flags = MSG_MORE | MSG_SENDPAGE_NOTLAST;
 	int		slen;
 	int		len = 0;
 
@@ -399,6 +399,31 @@ 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.
  */
@@ -414,7 +439,7 @@ static void svc_udp_data_ready(struct sock *sk)
 		set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
 		svc_xprt_enqueue(&svsk->sk_xprt);
 	}
-	if (wq && waitqueue_active(wq))
+	if (sunrpc_waitqueue_active(wq))
 		wake_up_interruptible(wq);
 }
 
@@ -432,7 +457,7 @@ static void svc_write_space(struct sock *sk)
 		svc_xprt_enqueue(&svsk->sk_xprt);
 	}
 
-	if (wq && waitqueue_active(wq)) {
+	if (sunrpc_waitqueue_active(wq)) {
 		dprintk("RPC svc_write_space: someone sleeping on %p\n",
 		       svsk);
 		wake_up_interruptible(wq);
@@ -787,7 +812,7 @@ static void svc_tcp_listen_data_ready(struct sock *sk)
 	}
 
 	wq = sk_sleep(sk);
-	if (wq && waitqueue_active(wq))
+	if (sunrpc_waitqueue_active(wq))
 		wake_up_interruptible_all(wq);
 }
 
@@ -808,7 +833,7 @@ static void svc_tcp_state_change(struct sock *sk)
 		set_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags);
 		svc_xprt_enqueue(&svsk->sk_xprt);
 	}
-	if (wq && waitqueue_active(wq))
+	if (sunrpc_waitqueue_active(wq))
 		wake_up_interruptible_all(wq);
 }
 
@@ -823,7 +848,7 @@ static void svc_tcp_data_ready(struct sock *sk)
 		set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
 		svc_xprt_enqueue(&svsk->sk_xprt);
 	}
-	if (wq && waitqueue_active(wq))
+	if (sunrpc_waitqueue_active(wq))
 		wake_up_interruptible(wq);
 }
 
@@ -1367,7 +1392,6 @@ EXPORT_SYMBOL_GPL(svc_sock_update_bufs);
 
 /*
  * Initialize socket for RPC use and create svc_sock struct
- * XXX: May want to setsockopt SO_SNDBUF and SO_RCVBUF.
  */
 static struct svc_sock *svc_setup_socket(struct svc_serv *serv,
 						struct socket *sock,
@@ -1594,7 +1618,7 @@ static void svc_sock_detach(struct svc_xprt *xprt)
 	sk->sk_write_space = svsk->sk_owspace;
 
 	wq = sk_sleep(sk);
-	if (wq && waitqueue_active(wq))
+	if (sunrpc_waitqueue_active(wq))
 		wake_up_interruptible(wq);
 }