SUNRPC: Move xprt_update_rtt callsite

Since commit 33849792 ("xprtrdma: Detect unreachable NFS/RDMA
servers more reliably"), the xprtrdma transport now has a ->timer
callout. But xprtrdma does not need to compute RTT data, only UDP
needs that. Move the xprt_update_rtt call into the UDP transport
implementation.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

include/linux/sunrpc/xprt.h

@@ -373,6 +373,7 @@ void			xprt_wait_for_buffer_space(struct rpc_task *task, rpc_action action);
 void			xprt_write_space(struct rpc_xprt *xprt);
 void			xprt_adjust_cwnd(struct rpc_xprt *xprt, struct rpc_task *task, int result);
 struct rpc_rqst *	xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid);
+void			xprt_update_rtt(struct rpc_task *task);
 void			xprt_complete_rqst(struct rpc_task *task, int copied);
 void			xprt_pin_rqst(struct rpc_rqst *req);
 void			xprt_unpin_rqst(struct rpc_rqst *req);

net/sunrpc/xprt.c

@@ -889,7 +889,13 @@ __must_hold(&req->rq_xprt->recv_lock)
 	}
 }
 
-static void xprt_update_rtt(struct rpc_task *task)
+/**
+ * xprt_update_rtt - Update RPC RTT statistics
+ * @task: RPC request that recently completed
+ *
+ * Caller holds xprt->recv_lock.
+ */
+void xprt_update_rtt(struct rpc_task *task)
 {
 	struct rpc_rqst *req = task->tk_rqstp;
 	struct rpc_rtt *rtt = task->tk_client->cl_rtt;
@@ -902,6 +908,7 @@ static void xprt_update_rtt(struct rpc_task *task)
 		rpc_set_timeo(rtt, timer, req->rq_ntrans - 1);
 	}
 }
+EXPORT_SYMBOL_GPL(xprt_update_rtt);
 
 /**
  * xprt_complete_rqst - called when reply processing is complete
@@ -921,8 +928,6 @@ void xprt_complete_rqst(struct rpc_task *task, int copied)
 
 	xprt->stat.recvs++;
 	req->rq_rtt = ktime_sub(ktime_get(), req->rq_xtime);
-	if (xprt->ops->timer != NULL)
-		xprt_update_rtt(task);
 
 	list_del_init(&req->rq_list);
 	req->rq_private_buf.len = copied;

net/sunrpc/xprtsock.c

@@ -1060,6 +1060,7 @@ static void xs_udp_data_read_skb(struct rpc_xprt *xprt,
 	if (!rovr)
 		goto out_unlock;
 	xprt_pin_rqst(rovr);
+	xprt_update_rtt(rovr->rq_task);
 	spin_unlock(&xprt->recv_lock);
 	task = rovr->rq_task;