Received-SPF: pass (google.com: domain of linux-nfs+bounces-2981-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:40f1:3f00::1 as permitted sender) client-ip=2604:1380:40f1:3f00::1;
From: Chen Hanxiao <chenhx.fnst@fujitsu.com>
To: Trond Myklebust <trond.myklebust@hammerspace.com>,
	Anna Schumaker <anna@kernel.org>,
	Chuck Lever <chuck.lever@oracle.com>,
	Jeff Layton <jlayton@kernel.org>,
	Neil Brown <neilb@suse.de>,
	Olga Kornievskaia <kolga@netapp.com>,
	Dai Ngo <Dai.Ngo@oracle.com>,
	Tom Talpey <tom@talpey.com>
Cc: linux-nfs@vger.kernel.org
Subject: [PATCH] SUNRPC: rpc_show_tasks: add an empty list check
Date: Wed, 24 Apr 2024 18:41:12 +0800
Message-Id: <20240424104112.1053-1-chenhx.fnst@fujitsu.com>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

add an empty list check, so we can get rid of some useless
list iterate or spin locks.

Signed-off-by: Chen Hanxiao <chenhx.fnst@fujitsu.com>
---
 net/sunrpc/clnt.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 28f3749f6dc6..749317587bb3 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -3345,8 +3345,13 @@ void rpc_show_tasks(struct net *net)
 	int header = 0;
 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 
+	if (list_empty(&sn->all_clients))
+		return;
+
 	spin_lock(&sn->rpc_client_lock);
 	list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
+		if (list_empty(&clnt->cl_tasks))
+			continue;
 		spin_lock(&clnt->cl_lock);
 		list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
 			if (!header) {
-- 
2.39.1