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net/sched: taprio: taprio_offload_config_changed() is protected by rtnl_mutex

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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 <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Vladimir Oltean 2022-09-15 13:50:40 +03:00 • committed by Jakub Kicinski
parent 4d3c884850
commit c8cbe123be
1 changed files with 2 additions and 8 deletions
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10
net/sched/sch_taprio.c
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@ -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)