Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 0b5d404e authored by Jarek Poplawski's avatar Jarek Poplawski Committed by David S. Miller
Browse files

pkt_sched: Fix lockdep warning on est_tree_lock in gen_estimator 



This patch fixes a lockdep warning:

[  516.287584] =========================================================
[  516.288386] [ INFO: possible irq lock inversion dependency detected ]
[  516.288386] 2.6.35b #7
[  516.288386] ---------------------------------------------------------
[  516.288386] swapper/0 just changed the state of lock:
[  516.288386]  (&qdisc_tx_lock){+.-...}, at: [<c12eacda>] est_timer+0x62/0x1b4
[  516.288386] but this lock took another, SOFTIRQ-unsafe lock in the past:
[  516.288386]  (est_tree_lock){+.+...}
[  516.288386] 
[  516.288386] and interrupts could create inverse lock ordering between them.
...

So, est_tree_lock needs BH protection because it's taken by
qdisc_tx_lock, which is used both in BH and process contexts.
(Full warning with this patch at netdev, 02 Sep 2010.)

Fixes commit: ae638c47
("pkt_sched: gen_estimator: add a new lock")

Signed-off-by: default avatarJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7bcbf81a

net/core/gen_estimator.c

+6 −6
Original line number Diff line number Diff line
@@ -232,7 +232,7 @@ int gen_new_estimator(struct gnet_stats_basic_packed *bstats, 
	est->last_packets = bstats->packets;

	est->avpps = rate_est->pps<<10;



	spin_lock(&est_tree_lock);

	spin_lock_bh(&est_tree_lock);

	if (!elist[idx].timer.function) {

		INIT_LIST_HEAD(&elist[idx].list);

		setup_timer(&elist[idx].timer, est_timer, idx);
@@ -243,7 +243,7 @@ int gen_new_estimator(struct gnet_stats_basic_packed *bstats, 


	list_add_rcu(&est->list, &elist[idx].list);

	gen_add_node(est);

	spin_unlock(&est_tree_lock);

	spin_unlock_bh(&est_tree_lock);



	return 0;

}
@@ -270,7 +270,7 @@ void gen_kill_estimator(struct gnet_stats_basic_packed *bstats, 
{

	struct gen_estimator *e;



	spin_lock(&est_tree_lock);

	spin_lock_bh(&est_tree_lock);

	while ((e = gen_find_node(bstats, rate_est))) {

		rb_erase(&e->node, &est_root);
@@ -281,7 +281,7 @@ void gen_kill_estimator(struct gnet_stats_basic_packed *bstats, 
		list_del_rcu(&e->list);

		call_rcu(&e->e_rcu, __gen_kill_estimator);

	}

	spin_unlock(&est_tree_lock);

	spin_unlock_bh(&est_tree_lock);

}

EXPORT_SYMBOL(gen_kill_estimator);
@@ -320,9 +320,9 @@ bool gen_estimator_active(const struct gnet_stats_basic_packed *bstats, 


	ASSERT_RTNL();



	spin_lock(&est_tree_lock);

	spin_lock_bh(&est_tree_lock);

	res = gen_find_node(bstats, rate_est) != NULL;

	spin_unlock(&est_tree_lock);

	spin_unlock_bh(&est_tree_lock);



	return res;

}