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authorEric Dumazet <eric.dumazet@gmail.com>2012-01-02 15:47:50 +0400
committerDavid S. Miller <davem@davemloft.net>2012-01-03 22:02:19 +0400
commitd32ae76f2b776347051cf821ebe690602e38dfc7 (patch)
tree3f17a0c00e2ac7cc982c47e442661517ae010d5c /net/sched/sch_qfq.c
parentd47a0ac7b66883987275598d6039f902f4410ca9 (diff)
downloadlinux-d32ae76f2b776347051cf821ebe690602e38dfc7.tar.xz
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>
Diffstat (limited to 'net/sched/sch_qfq.c')
-rw-r--r--net/sched/sch_qfq.c17
1 files changed, 9 insertions, 8 deletions
diff --git a/net/sched/sch_qfq.c b/net/sched/sch_qfq.c
index 103343408593..2c5ff6148589 100644
--- a/net/sched/sch_qfq.c
+++ b/net/sched/sch_qfq.c
@@ -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;
}
- sch_tree_lock(sch);
- if (tb[TCA_QFQ_WEIGHT]) {
- q->wsum = weight - ONE_FP / cl->inv_w;
+ if (inv_w != cl->inv_w) {
+ sch_tree_lock(sch);
+ q->wsum += delta_w;
cl->inv_w = inv_w;
+ sch_tree_unlock(sch);
}
- 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);