From c8cbe123be6de9deff5e5312af8848362a919f97 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Thu, 15 Sep 2022 13:50:40 +0300 Subject: [PATCH] net/sched: taprio: taprio_offload_config_changed() is protected by rtnl_mutex The locking in taprio_offload_config_changed() is wrong (but also inconsequentially so). The current_entry_lock does not serialize changes to the admin and oper schedules, only to the current entry. In fact, the rtnl_mutex does that, and that is taken at the time when taprio_change() is called. Replace the rcu_dereference_protected() method with the proper RCU annotation, and drop the unnecessary spin lock. Signed-off-by: Vladimir Oltean Signed-off-by: Jakub Kicinski --- net/sched/sch_taprio.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index db88a69..e9f57ef 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1193,16 +1193,10 @@ static void taprio_offload_config_changed(struct taprio_sched *q) { struct sched_gate_list *oper, *admin; - spin_lock(&q->current_entry_lock); - - oper = rcu_dereference_protected(q->oper_sched, - lockdep_is_held(&q->current_entry_lock)); - admin = rcu_dereference_protected(q->admin_sched, - lockdep_is_held(&q->current_entry_lock)); + oper = rtnl_dereference(q->oper_sched); + admin = rtnl_dereference(q->admin_sched); switch_schedules(q, &admin, &oper); - - spin_unlock(&q->current_entry_lock); } static u32 tc_map_to_queue_mask(struct net_device *dev, u32 tc_mask) -- 2.7.4