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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 fc59d5bdf1 ("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: fc59d5bdf1 ("pkt_sched: fq: clear time_next_packet for reused flows")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2018-05-02 10:03:30 -07:00 committed by David S. Miller
parent 30ca22e4a5
commit 7df40c2673
1 changed files with 25 additions and 12 deletions
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37
net/sched/sch_fq.c
View File

@ -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);
}
}