sunrpc: Save remote presentation address in svc_xprt for trace events

TP_printk defines a format string that is passed to user space for
converting raw trace event records to something human-readable.

My user space's printf (Oracle Linux 7), however, does not have a
%pI format specifier. The result is that what is supposed to be an
IP address in the output of "trace-cmd report" is just a string that
says the field couldn't be displayed.

To fix this, adopt the same approach as the client: maintain a pre-
formated presentation address for occasions when %pI is not
available.

The location of the trace_svc_send trace point is adjusted so that
rqst->rq_xprt is not NULL when the trace event is recorded.

Signed-off-by: Chuck Lever <[e-mail]>
Signed-off-by: J. Bruce Fields <[e-mail]>

include/linux/sunrpc/svc_xprt.h

···
 	size_t			xpt_locallen;	/* length of address */
 	struct sockaddr_storage	xpt_remote;	/* remote peer's address */
 	size_t			xpt_remotelen;	/* length of address */
+	char			xpt_remotebuf[INET6_ADDRSTRLEN + 10];
 	struct rpc_wait_queue	xpt_bc_pending;	/* backchannel wait queue */
 	struct list_head	xpt_users;	/* callbacks on free */
 
···
 {
 	memcpy(&xprt->xpt_remote, sa, salen);
 	xprt->xpt_remotelen = salen;
+	snprintf(xprt->xpt_remotebuf, sizeof(xprt->xpt_remotebuf) - 1,
+		 "%pISpc", sa);
 }
+
 static inline unsigned short svc_addr_port(const struct sockaddr *sa)
 {
 	const struct sockaddr_in *sin = (const struct sockaddr_in *)sa;

include/trace/events/sunrpc.h

···
 		__field(u32, xid)
 		__field(int, len)
 		__field(unsigned long, flags)
-		__dynamic_array(unsigned char, addr, rqst->rq_addrlen)
+		__string(addr, rqst->rq_xprt->xpt_remotebuf)
 	),
 
 	TP_fast_assign(
 		__entry->xid = be32_to_cpu(rqst->rq_xid);
 		__entry->len = len;
 		__entry->flags = rqst->rq_flags;
-		memcpy(__get_dynamic_array(addr),
-			&rqst->rq_addr, rqst->rq_addrlen);
+		__assign_str(addr, rqst->rq_xprt->xpt_remotebuf);
 	),
 
-	TP_printk("addr=%pIScp xid=0x%08x len=%d flags=%s",
-			(struct sockaddr *)__get_dynamic_array(addr),
-			__entry->xid, __entry->len,
+	TP_printk("addr=%s xid=0x%08x len=%d flags=%s",
+			__get_str(addr), __entry->xid, __entry->len,
 			show_rqstp_flags(__entry->flags))
 );
 
···
 	TP_STRUCT__entry(
 		__field(u32, xid)
 		__field(unsigned long, flags)
-		__dynamic_array(unsigned char, addr, rqst->rq_addrlen)
+		__string(addr, rqst->rq_xprt->xpt_remotebuf)
 	),
 
 	TP_fast_assign(
 		__entry->xid = be32_to_cpu(rqst->rq_xid);
 		__entry->flags = rqst->rq_flags;
-		memcpy(__get_dynamic_array(addr),
-			&rqst->rq_addr, rqst->rq_addrlen);
+		__assign_str(addr, rqst->rq_xprt->xpt_remotebuf);
 	),
 
-	TP_printk("addr=%pIScp rq_xid=0x%08x flags=%s",
-		(struct sockaddr *)__get_dynamic_array(addr),
-		__entry->xid,
-		show_rqstp_flags(__entry->flags))
+	TP_printk("addr=%s xid=0x%08x flags=%s",
+			__get_str(addr), __entry->xid,
+			show_rqstp_flags(__entry->flags))
 );
 
 DEFINE_EVENT(svc_rqst_event, svc_defer,
···
 		__field(u32, xid)
 		__field(int, status)
 		__field(unsigned long, flags)
-		__dynamic_array(unsigned char, addr, rqst->rq_addrlen)
+		__string(addr, rqst->rq_xprt->xpt_remotebuf)
 	),
 
 	TP_fast_assign(
 		__entry->xid = be32_to_cpu(rqst->rq_xid);
 		__entry->status = status;
 		__entry->flags = rqst->rq_flags;
-		memcpy(__get_dynamic_array(addr),
-			&rqst->rq_addr, rqst->rq_addrlen);
+		__assign_str(addr, rqst->rq_xprt->xpt_remotebuf);
 	),
 
-	TP_printk("addr=%pIScp rq_xid=0x%08x status=%d flags=%s",
-		(struct sockaddr *)__get_dynamic_array(addr),
-		__entry->xid,
-		__entry->status, show_rqstp_flags(__entry->flags))
+	TP_printk("addr=%s xid=0x%08x status=%d flags=%s",
+		  __get_str(addr), __entry->xid,
+		  __entry->status, show_rqstp_flags(__entry->flags))
 );
 
 DEFINE_EVENT(svc_rqst_status, svc_process,
···
 		__field(struct svc_xprt *, xprt)
 		__field(int, pid)
 		__field(unsigned long, flags)
-		__dynamic_array(unsigned char, addr, xprt != NULL ?
-			xprt->xpt_remotelen : 0)
+		__string(addr, xprt->xpt_remotebuf)
 	),
 
 	TP_fast_assign(
 		__entry->xprt = xprt;
 		__entry->pid = rqst? rqst->rq_task->pid : 0;
-		if (xprt) {
-			memcpy(__get_dynamic_array(addr),
-				&xprt->xpt_remote,
-				xprt->xpt_remotelen);
-			__entry->flags = xprt->xpt_flags;
-		} else
-			__entry->flags = 0;
+		__entry->flags = xprt->xpt_flags;
+		__assign_str(addr, xprt->xpt_remotebuf);
 	),
 
-	TP_printk("xprt=0x%p addr=%pIScp pid=%d flags=%s", __entry->xprt,
-		__get_dynamic_array_len(addr) != 0 ?
-			(struct sockaddr *)__get_dynamic_array(addr) : NULL,
-		__entry->pid, show_svc_xprt_flags(__entry->flags))
+	TP_printk("xprt=%p addr=%s pid=%d flags=%s",
+			__entry->xprt, __get_str(addr),
+			__entry->pid, show_svc_xprt_flags(__entry->flags))
 );
 
 DECLARE_EVENT_CLASS(svc_xprt_event,
···
 	TP_STRUCT__entry(
 		__field(struct svc_xprt *, xprt)
 		__field(unsigned long, flags)
-		__dynamic_array(unsigned char, addr, xprt->xpt_remotelen)
+		__string(addr, xprt->xpt_remotebuf)
 	),
 
 	TP_fast_assign(
 		__entry->xprt = xprt;
 		__entry->flags = xprt->xpt_flags;
-		memcpy(__get_dynamic_array(addr),
-		       &xprt->xpt_remote, xprt->xpt_remotelen);
+		__assign_str(addr, xprt->xpt_remotebuf);
 	),
 
-	TP_printk("xprt=0x%p addr=%pIScp flags=%s", __entry->xprt,
-		(struct sockaddr *)__get_dynamic_array(addr),
-		show_svc_xprt_flags(__entry->flags))
+	TP_printk("xprt=%p addr=%s flags=%s",
+			__entry->xprt, __get_str(addr),
+			show_svc_xprt_flags(__entry->flags))
 );
 
 DEFINE_EVENT(svc_xprt_event, svc_xprt_dequeue,
···
 		__field(struct svc_xprt *, xprt)
 		__field(int, len)
 		__field(unsigned long, flags)
-		__dynamic_array(unsigned char, addr, xprt != NULL ?
-			xprt->xpt_remotelen : 0)
+		__string(addr, xprt->xpt_remotebuf)
 	),
 
 	TP_fast_assign(
 		__entry->xprt = xprt;
 		__entry->len = len;
-		if (xprt) {
-			memcpy(__get_dynamic_array(addr),
-					&xprt->xpt_remote,
-					xprt->xpt_remotelen);
-			__entry->flags = xprt->xpt_flags;
-		} else
-			__entry->flags = 0;
+		__entry->flags = xprt->xpt_flags;
+		__assign_str(addr, xprt->xpt_remotebuf);
 	),
 
-	TP_printk("xprt=0x%p addr=%pIScp len=%d flags=%s", __entry->xprt,
-		__get_dynamic_array_len(addr) != 0 ?
-			(struct sockaddr *)__get_dynamic_array(addr) : NULL,
+	TP_printk("xprt=%p addr=%s len=%d flags=%s",
+		__entry->xprt, __get_str(addr),
 		__entry->len, show_svc_xprt_flags(__entry->flags))
 );
 
···
 
 	TP_STRUCT__entry(
 		__field(u32, xid)
-		__dynamic_array(unsigned char, addr, dr->addrlen)
+		__string(addr, dr->xprt->xpt_remotebuf)
 	),
 
 	TP_fast_assign(
 		__entry->xid = be32_to_cpu(*(__be32 *)(dr->args +
 						       (dr->xprt_hlen>>2)));
-		memcpy(__get_dynamic_array(addr), &dr->addr, dr->addrlen);
+		__assign_str(addr, dr->xprt->xpt_remotebuf);
 	),
 
-	TP_printk("addr=%pIScp xid=0x%08x",
-		(struct sockaddr *)__get_dynamic_array(addr),
-		__entry->xid)
+	TP_printk("addr=%s xid=0x%08x", __get_str(addr), __entry->xid)
 );
 
 DEFINE_EVENT(svc_deferred_event, svc_drop_deferred,

net/sunrpc/svc_xprt.c

···
 	set_bit(XPT_BUSY, &xprt->xpt_flags);
 	rpc_init_wait_queue(&xprt->xpt_bc_pending, "xpt_bc_pending");
 	xprt->xpt_net = get_net(net);
+	strcpy(xprt->xpt_remotebuf, "uninitialized");
 }
 EXPORT_SYMBOL_GPL(svc_xprt_init);
 
···
 		len = xprt->xpt_ops->xpo_sendto(rqstp);
 	mutex_unlock(&xprt->xpt_mutex);
 	rpc_wake_up(&xprt->xpt_bc_pending);
+	trace_svc_send(rqstp, len);
 	svc_xprt_release(rqstp);
 
 	if (len == -ECONNREFUSED || len == -ENOTCONN || len == -EAGAIN)
 		len = 0;
 out:
-	trace_svc_send(rqstp, len);
 	return len;
 }
 

net/sunrpc/svcsock.c

···
 	set_bit(XPT_CONG_CTRL, &svsk->sk_xprt.xpt_flags);
 	if (sk->sk_state == TCP_LISTEN) {
 		dprintk("setting up TCP socket for listening\n");
+		strcpy(svsk->sk_xprt.xpt_remotebuf, "listener");
 		set_bit(XPT_LISTENER, &svsk->sk_xprt.xpt_flags);
 		sk->sk_data_ready = svc_tcp_listen_data_ready;
 		set_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags);

net/sunrpc/xprtrdma/svc_rdma_transport.c

···
 	 */
 	set_bit(XPT_CONG_CTRL, &cma_xprt->sc_xprt.xpt_flags);
 
-	if (listener)
+	if (listener) {
+		strcpy(cma_xprt->sc_xprt.xpt_remotebuf, "listener");
 		set_bit(XPT_LISTENER, &cma_xprt->sc_xprt.xpt_flags);
+	}
 
 	return cma_xprt;
 }