[PKT_SCHED]: Fix 'SFQ qdisc crashes with limit of 2 packets'

Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c
index 9579573098598df19066e0910e181e68a94ef080..3a23e30bc79e3689dc1f16fc9c16d0d76f820865 100644 (file)
--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -270,7 +270,7 @@ sfq_enqueue(struct sk_buff *skb, struct Qdisc* sch)
                        q->tail = x;
                }
        }
-       if (++sch->q.qlen < q->limit-1) {
+       if (++sch->q.qlen <= q->limit) {
                sch->bstats.bytes += skb->len;
                sch->bstats.packets++;
                return 0;
@@ -306,7 +306,7 @@ sfq_requeue(struct sk_buff *skb, struct Qdisc* sch)
                        q->tail = x;
                }
        }
-       if (++sch->q.qlen < q->limit - 1) {
+       if (++sch->q.qlen <= q->limit) {
                sch->qstats.requeues++;
                return 0;
        }
@@ -391,10 +391,10 @@ static int sfq_change(struct Qdisc *sch, struct rtattr *opt)
        q->quantum = ctl->quantum ? : psched_mtu(sch->dev);
        q->perturb_period = ctl->perturb_period*HZ;
        if (ctl->limit)
-               q->limit = min_t(u32, ctl->limit, SFQ_DEPTH);
+               q->limit = min_t(u32, ctl->limit, SFQ_DEPTH - 2);
 
        qlen = sch->q.qlen;
-       while (sch->q.qlen >= q->limit-1)
+       while (sch->q.qlen > q->limit)
                sfq_drop(sch);
        qdisc_tree_decrease_qlen(sch, qlen - sch->q.qlen);
 
@@ -423,7 +423,7 @@ static int sfq_init(struct Qdisc *sch, struct rtattr *opt)
                q->dep[i+SFQ_DEPTH].next = i+SFQ_DEPTH;
                q->dep[i+SFQ_DEPTH].prev = i+SFQ_DEPTH;
        }
-       q->limit = SFQ_DEPTH;
+       q->limit = SFQ_DEPTH - 2;
        q->max_depth = 0;
        q->tail = SFQ_DEPTH;
        if (opt == NULL) {