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sch_qfq: accurate wsum handling 

We can underestimate q->wsum in case of "tc class replace ... qfq"
and/or qdisc_create_dflt() error.

wsum is not really used in fast path, only at qfq qdisc/class setup,
to catch user error.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2012-01-02 11:47:50 +00:00 committed by David S. Miller
parent d47a0ac7b6
commit d32ae76f2b
1 changed files with 9 additions and 8 deletions
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15
net/sched/sch_qfq.c
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@ -211,6 +211,7 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
struct nlattr *tb[TCA_QFQ_MAX + 1];
u32 weight, lmax, inv_w;
int i, err;
int delta_w;
if (tca[TCA_OPTIONS] == NULL) {
pr_notice("qfq: no options\n");
@ -232,9 +233,10 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
inv_w = ONE_FP / weight;
weight = ONE_FP / inv_w;
if (q->wsum + weight > QFQ_MAX_WSUM) {
delta_w = weight - (cl ? ONE_FP / cl->inv_w : 0);
if (q->wsum + delta_w > QFQ_MAX_WSUM) {
pr_notice("qfq: total weight out of range (%u + %u)\n",
weight, q->wsum);
delta_w, q->wsum);
return -EINVAL;
}
@ -256,13 +258,12 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
return err;
}
if (inv_w != cl->inv_w) {
sch_tree_lock(sch);
if (tb[TCA_QFQ_WEIGHT]) {
q->wsum = weight - ONE_FP / cl->inv_w;
q->wsum += delta_w;
cl->inv_w = inv_w;
}
sch_tree_unlock(sch);
}
return 0;
}
@ -277,7 +278,6 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
i = qfq_calc_index(cl->inv_w, cl->lmax);
cl->grp = &q->groups[i];
q->wsum += weight;
cl->qdisc = qdisc_create_dflt(sch->dev_queue,
&pfifo_qdisc_ops, classid);
@ -294,6 +294,7 @@ static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
return err;
}
}
q->wsum += weight;
sch_tree_lock(sch);
qdisc_class_hash_insert(&q->clhash, &cl->common);