sunrpc: Simplify do_enqueue tracing

There are three cases where svc_xprt_do_enqueue() returns without
waking an nfsd thread:

1. There is no work to do

2. The transport is already busy

3. There are no available nfsd threads

Only 3. is truly interesting. Move the trace point so it records
that there was work to do and either an nfsd thread was awoken, or
a free one could not found.

As an additional clean up, remove a redundant comment and a couple
of dprintk call sites.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

net/sunrpc/svc_xprt.c

@@ -382,25 +382,21 @@ void svc_xprt_do_enqueue(struct svc_xprt *xprt)
 	int cpu;
 
 	if (!svc_xprt_has_something_to_do(xprt))
-		goto out;
+		return;
 
 	/* Mark transport as busy. It will remain in this state until
 	 * the provider calls svc_xprt_received. We update XPT_BUSY
 	 * atomically because it also guards against trying to enqueue
 	 * the transport twice.
 	 */
-	if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags)) {
-		/* Don't enqueue transport while already enqueued */
-		dprintk("svc: transport %p busy, not enqueued\n", xprt);
-		goto out;
-	}
+	if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
+		return;
 
 	cpu = get_cpu();
 	pool = svc_pool_for_cpu(xprt->xpt_server, cpu);
 
 	atomic_long_inc(&pool->sp_stats.packets);
 
-	dprintk("svc: transport %p put into queue\n", xprt);
 	spin_lock_bh(&pool->sp_lock);
 	list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
 	pool->sp_stats.sockets_queued++;
@@ -420,7 +416,6 @@ void svc_xprt_do_enqueue(struct svc_xprt *xprt)
 out_unlock:
 	rcu_read_unlock();
 	put_cpu();
-out:
 	trace_svc_xprt_do_enqueue(xprt, rqstp);
 }
 EXPORT_SYMBOL_GPL(svc_xprt_do_enqueue);