Commit 7df40c26 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net_sched: fq: take care of throttled flows before reuse 



Normally, a socket can not be freed/reused unless all its TX packets
left qdisc and were TX-completed. However connect(AF_UNSPEC) allows
this to happen.

With commit fc59d5bd ("pkt_sched: fq: clear time_next_packet for
reused flows") we cleared f->time_next_packet but took no special
action if the flow was still in the throttled rb-tree.

Since f->time_next_packet is the key used in the rb-tree searches,
blindly clearing it might break rb-tree integrity. We need to make
sure the flow is no longer in the rb-tree to avoid this problem.

Fixes: fc59d5bd ("pkt_sched: fq: clear time_next_packet for reused flows")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 30ca22e4

net/sched/sch_fq.c

+25 −12
Original line number Diff line number Diff line
@@ -128,6 +128,28 @@ static bool fq_flow_is_detached(const struct fq_flow *f) 
	return f->next == &detached;

}



static bool fq_flow_is_throttled(const struct fq_flow *f)

{

	return f->next == &throttled;

}



static void fq_flow_add_tail(struct fq_flow_head *head, struct fq_flow *flow)

{

	if (head->first)

		head->last->next = flow;

	else

		head->first = flow;

	head->last = flow;

	flow->next = NULL;

}



static void fq_flow_unset_throttled(struct fq_sched_data *q, struct fq_flow *f)

{

	rb_erase(&f->rate_node, &q->delayed);

	q->throttled_flows--;

	fq_flow_add_tail(&q->old_flows, f);

}



static void fq_flow_set_throttled(struct fq_sched_data *q, struct fq_flow *f)

{

	struct rb_node **p = &q->delayed.rb_node, *parent = NULL;
@@ -155,15 +177,6 @@ static void fq_flow_set_throttled(struct fq_sched_data *q, struct fq_flow *f) 


static struct kmem_cache *fq_flow_cachep __read_mostly;



static void fq_flow_add_tail(struct fq_flow_head *head, struct fq_flow *flow)

{

	if (head->first)

		head->last->next = flow;

	else

		head->first = flow;

	head->last = flow;

	flow->next = NULL;

}



/* limit number of collected flows per round */

#define FQ_GC_MAX 8
@@ -267,6 +280,8 @@ static struct fq_flow *fq_classify(struct sk_buff *skb, struct fq_sched_data *q) 
				     f->socket_hash != sk->sk_hash)) {

				f->credit = q->initial_quantum;

				f->socket_hash = sk->sk_hash;

				if (fq_flow_is_throttled(f))

					fq_flow_unset_throttled(q, f);

				f->time_next_packet = 0ULL;

			}

			return f;
@@ -438,9 +453,7 @@ static void fq_check_throttled(struct fq_sched_data *q, u64 now) 
			q->time_next_delayed_flow = f->time_next_packet;

			break;

		}

		rb_erase(p, &q->delayed);

		q->throttled_flows--;

		fq_flow_add_tail(&q->old_flows, f);

		fq_flow_unset_throttled(q, f);

	}

}

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