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Commit 2818fa0f authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
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pkt_sched: fq: do not hold qdisc lock while allocating memory 



Resizing fq hash table allocates memory while holding qdisc spinlock,
with BH disabled.

This is definitely not good, as allocation might sleep.

We can drop the lock and get it when needed, we hold RTNL so no other
changes can happen at the same time.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Fixes: afe4fd06 ("pkt_sched: fq: Fair Queue packet scheduler")
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent bc48bc80

net/sched/sch_fq.c

+15 −6
Original line number Original line Diff line number Diff line
@@ -601,6 +601,7 @@ static int fq_resize(struct Qdisc *sch, u32 log) 
{

{

	struct fq_sched_data *q = qdisc_priv(sch);

	struct fq_sched_data *q = qdisc_priv(sch);

	struct rb_root *array;

	struct rb_root *array;

	void *old_fq_root;

	u32 idx;

	u32 idx;





	if (q->fq_root && log == q->fq_trees_log)

	if (q->fq_root && log == q->fq_trees_log)
@@ -615,13 +616,19 @@ static int fq_resize(struct Qdisc *sch, u32 log) 
	for (idx = 0; idx < (1U << log); idx++)

	for (idx = 0; idx < (1U << log); idx++)

		array[idx] = RB_ROOT;

		array[idx] = RB_ROOT;





	if (q->fq_root) {

	sch_tree_lock(sch);

		fq_rehash(q, q->fq_root, q->fq_trees_log, array, log);



		fq_free(q->fq_root);

	old_fq_root = q->fq_root;

	}

	if (old_fq_root)

		fq_rehash(q, old_fq_root, q->fq_trees_log, array, log);



	q->fq_root = array;

	q->fq_root = array;

	q->fq_trees_log = log;

	q->fq_trees_log = log;





	sch_tree_unlock(sch);



	fq_free(old_fq_root);



	return 0;

	return 0;

}

}
@@ -697,9 +704,11 @@ static int fq_change(struct Qdisc *sch, struct nlattr *opt) 
		q->flow_refill_delay = usecs_to_jiffies(usecs_delay);

		q->flow_refill_delay = usecs_to_jiffies(usecs_delay);

	}

	}





	if (!err)

	if (!err) {

		sch_tree_unlock(sch);

		err = fq_resize(sch, fq_log);

		err = fq_resize(sch, fq_log);



		sch_tree_lock(sch);

	}

	while (sch->q.qlen > sch->limit) {

	while (sch->q.qlen > sch->limit) {

		struct sk_buff *skb = fq_dequeue(sch);

		struct sk_buff *skb = fq_dequeue(sch);