From 2574ba26e52a06131725c5beeb6b505aee6ca54a Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Thu, 1 Feb 2024 17:30:31 +0000
Subject: [PATCH] ipv6: make addrconf_wq single threaded

commit dfd2ee086a63c730022cb095576a8b3a5a752109 upstream.

Both addrconf_verify_work() and addrconf_dad_work() acquire rtnl,
there is no point trying to have one thread per cpu.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240201173031.3654257-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Brett A C Sheffield <bacs@librecast.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 4cb17b11c8af2fa9de840ffe7fc0bb712f894242)
---
 net/ipv6/addrconf.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 74f7f3e8d960..f6188bd9f55b 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -7383,7 +7383,8 @@ int __init addrconf_init(void)
 	if (err < 0)
 		goto out_addrlabel;
 
-	addrconf_wq = create_workqueue("ipv6_addrconf");
+	/* All works using addrconf_wq need to lock rtnl. */
+	addrconf_wq = create_singlethread_workqueue("ipv6_addrconf");
 	if (!addrconf_wq) {
 		err = -ENOMEM;
 		goto out_nowq;