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: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/gen_estimator.c

@@ -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;
 }