xprtrdma: Clean up trace_xprtrdma_nomrs()

- Rename it following the "_err" suffix convention
- Replace display of kernel memory addresses
- Tie MR exhaustion to a peer IP address, similar to the createmrs
   tracepoint
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

include/trace/events/rpcrdma.h

@@ -545,32 +545,33 @@ TRACE_EVENT(xprtrdma_mr_get,
 	)
 );
 
-TRACE_EVENT(xprtrdma_nomrs,
+TRACE_EVENT(xprtrdma_nomrs_err,
 	TP_PROTO(
+		const struct rpcrdma_xprt *r_xprt,
 		const struct rpcrdma_req *req
 	),
 
-	TP_ARGS(req),
+	TP_ARGS(r_xprt, req),
 
 	TP_STRUCT__entry(
-		__field(const void *, req)
 		__field(unsigned int, task_id)
 		__field(unsigned int, client_id)
-		__field(u32, xid)
+		__string(addr, rpcrdma_addrstr(r_xprt))
+		__string(port, rpcrdma_portstr(r_xprt))
 	),
 
 	TP_fast_assign(
 		const struct rpc_rqst *rqst = &req->rl_slot;
 
-		__entry->req = req;
 		__entry->task_id = rqst->rq_task->tk_pid;
 		__entry->client_id = rqst->rq_task->tk_client->cl_clid;
-		__entry->xid = be32_to_cpu(rqst->rq_xid);
+		__assign_str(addr, rpcrdma_addrstr(r_xprt));
+		__assign_str(port, rpcrdma_portstr(r_xprt));
 	),
 
-	TP_printk("task:%u@%u xid=0x%08x req=%p",
-		__entry->task_id, __entry->client_id, __entry->xid,
-		__entry->req
+	TP_printk("peer=[%s]:%s task:%u@%u",
+		__get_str(addr), __get_str(port),
+		__entry->task_id, __entry->client_id
 	)
 );
 

net/sunrpc/xprtrdma/rpc_rdma.c

@@ -323,7 +323,7 @@ static struct rpcrdma_mr_seg *rpcrdma_mr_prepare(struct rpcrdma_xprt *r_xprt,
 	return frwr_map(r_xprt, seg, nsegs, writing, req->rl_slot.rq_xid, *mr);
 
 out_getmr_err:
-	trace_xprtrdma_nomrs(req);
+	trace_xprtrdma_nomrs_err(r_xprt, req);
 	xprt_wait_for_buffer_space(&r_xprt->rx_xprt);
 	rpcrdma_mrs_refresh(r_xprt);
 	return ERR_PTR(-EAGAIN);