SUNRPC: Replace dprintk() call site in xs_nospace()

"no socket space" is an exceptional and infrequent condition
that troubleshooters want to know about.

Signed-off-by: Chuck Lever <[e-mail]>
Signed-off-by: Anna Schumaker <[e-mail]>

include/trace/events/sunrpc.h

···
 DEFINE_RPC_SOCKET_EVENT(rpc_socket_close);
 DEFINE_RPC_SOCKET_EVENT(rpc_socket_shutdown);
 
+TRACE_EVENT(rpc_socket_nospace,
+	TP_PROTO(
+		const struct rpc_rqst *rqst,
+		const struct sock_xprt *transport
+	),
+
+	TP_ARGS(rqst, transport),
+
+	TP_STRUCT__entry(
+		__field(unsigned int, task_id)
+		__field(unsigned int, client_id)
+		__field(unsigned int, total)
+		__field(unsigned int, remaining)
+	),
+
+	TP_fast_assign(
+		__entry->task_id = rqst->rq_task->tk_pid;
+		__entry->client_id = rqst->rq_task->tk_client->cl_clid;
+		__entry->total = rqst->rq_slen;
+		__entry->remaining = rqst->rq_slen - transport->xmit.offset;
+	),
+
+	TP_printk("task:%u@%u total=%u remaining=%u",
+		__entry->task_id, __entry->client_id,
+		__entry->total, __entry->remaining
+	)
+);
+
 TRACE_DEFINE_ENUM(XPRT_LOCKED);
 TRACE_DEFINE_ENUM(XPRT_CONNECTED);
 TRACE_DEFINE_ENUM(XPRT_CONNECTING);

net/sunrpc/xprtsock.c

···
 	struct sock *sk = transport->inet;
 	int ret = -EAGAIN;
 
-	dprintk("RPC: %5u xmit incomplete (%u left of %u)\n",
-			req->rq_task->tk_pid,
-			req->rq_slen - transport->xmit.offset,
-			req->rq_slen);
+	trace_rpc_socket_nospace(req, transport);
 
 	/* Protect against races with write_space */
 	spin_lock(&xprt->transport_lock);