From: Vladimir Oltean <vladimir.oltean@xxxxxxx> [ Upstream commit 18cdd2f0998a4967b1fff4c43ed9aef049e42c39 ] Since the writer-side lock is taken here, we do not need to open an RCU read-side critical section, instead we can use rtnl_dereference() to tell lockdep we are serialized with concurrent writes. Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx> Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- net/sched/sch_taprio.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index 86675a79da1e..71408136d4a0 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1492,10 +1492,8 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt, } INIT_LIST_HEAD(&new_admin->entries); - rcu_read_lock(); - oper = rcu_dereference(q->oper_sched); - admin = rcu_dereference(q->admin_sched); - rcu_read_unlock(); + oper = rtnl_dereference(q->oper_sched); + admin = rtnl_dereference(q->admin_sched); /* no changes - no new mqprio settings */ if (!taprio_mqprio_cmp(dev, mqprio)) @@ -1888,9 +1886,8 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb) struct nlattr *nest, *sched_nest; unsigned int i; - rcu_read_lock(); - oper = rcu_dereference(q->oper_sched); - admin = rcu_dereference(q->admin_sched); + oper = rtnl_dereference(q->oper_sched); + admin = rtnl_dereference(q->admin_sched); opt.num_tc = netdev_get_num_tc(dev); memcpy(opt.prio_tc_map, dev->prio_tc_map, sizeof(opt.prio_tc_map)); @@ -1934,8 +1931,6 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb) nla_nest_end(skb, sched_nest); done: - rcu_read_unlock(); - return nla_nest_end(skb, nest); admin_error: @@ -1945,7 +1940,6 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb) nla_nest_cancel(skb, nest); start_error: - rcu_read_unlock(); return -ENOSPC; } -- 2.35.1
