sunrpc: add new tracepoints in xprt handling code

...so we can keep track of when calls are sent and replies received.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 3b305ab..b63e262 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -1454,12 +1454,15 @@
 	struct rpc_xprt *xprt;
 	read_descriptor_t rd_desc;
 	int read;
+	unsigned long total = 0;
 
 	dprintk("RPC:       xs_tcp_data_ready...\n");
 
 	read_lock_bh(&sk->sk_callback_lock);
-	if (!(xprt = xprt_from_sock(sk)))
+	if (!(xprt = xprt_from_sock(sk))) {
+		read = 0;
 		goto out;
+	}
 	/* Any data means we had a useful conversation, so
 	 * the we don't need to delay the next reconnect
 	 */
@@ -1471,8 +1474,11 @@
 	do {
 		rd_desc.count = 65536;
 		read = tcp_read_sock(sk, &rd_desc, xs_tcp_data_recv);
+		if (read > 0)
+			total += read;
 	} while (read > 0);
 out:
+	trace_xs_tcp_data_ready(xprt, read, total);
 	read_unlock_bh(&sk->sk_callback_lock);
 }