From: Vladimir Oltean vladimir.oltean@nxp.com
[ 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@nxp.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 ae7ca68f2cf9..0ac3fbc13b7e 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1491,10 +1491,8 @@ 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)) @@ -1887,9 +1885,8 @@ 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)); @@ -1933,8 +1930,6 @@ 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: @@ -1944,7 +1939,6 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb) nla_nest_cancel(skb, nest);
start_error: - rcu_read_unlock(); return -ENOSPC; }