Commit 926e61b7 authored by Jarek Poplawski's avatar Jarek Poplawski Committed by David S. Miller
Browse files

pkt_sched: Fix tx queue selection in tc_modify_qdisc

After the recent mq change there is the new select_queue qdisc class
method used in tc_modify_qdisc, but it works OK only for direct child
qdiscs of mq qdisc. Grandchildren always get the first tx queue, which
would give wrong qdisc_root etc. results (e.g. for sch_htb as child of
sch_prio). This patch fixes it by using parent's dev_queue for such
grandchildren qdiscs. The select_queue method's return type is changed

With feedback from: Patrick McHardy <>

Signed-off-by: default avatarJarek Poplawski <>
Signed-off-by: default avatarDavid S. Miller <>
parent ca519274
......@@ -81,7 +81,7 @@ struct Qdisc
struct Qdisc_class_ops
/* Child qdisc manipulation */
unsigned int (*select_queue)(struct Qdisc *, struct tcmsg *);
struct netdev_queue * (*select_queue)(struct Qdisc *, struct tcmsg *);
int (*graft)(struct Qdisc *, unsigned long cl,
struct Qdisc *, struct Qdisc **);
struct Qdisc * (*leaf)(struct Qdisc *, unsigned long cl);
......@@ -1116,12 +1116,16 @@ static int tc_modify_qdisc(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
tcm->tcm_parent, tcm->tcm_parent,
tca, &err);
else {
unsigned int ntx = 0;
struct netdev_queue *dev_queue;
if (p && p->ops->cl_ops && p->ops->cl_ops->select_queue)
ntx = p->ops->cl_ops->select_queue(p, tcm);
dev_queue = p->ops->cl_ops->select_queue(p, tcm);
else if (p)
dev_queue = p->dev_queue;
dev_queue = netdev_get_tx_queue(dev, 0);
q = qdisc_create(dev, netdev_get_tx_queue(dev, ntx), p,
q = qdisc_create(dev, dev_queue, p,
tcm->tcm_parent, tcm->tcm_handle,
tca, &err);
......@@ -125,13 +125,18 @@ static struct netdev_queue *mq_queue_get(struct Qdisc *sch, unsigned long cl)
return netdev_get_tx_queue(dev, ntx);
static unsigned int mq_select_queue(struct Qdisc *sch, struct tcmsg *tcm)
static struct netdev_queue *mq_select_queue(struct Qdisc *sch,
struct tcmsg *tcm)
unsigned int ntx = TC_H_MIN(tcm->tcm_parent);
struct netdev_queue *dev_queue = mq_queue_get(sch, ntx);
if (!mq_queue_get(sch, ntx))
return 0;
return ntx - 1;
if (!dev_queue) {
struct net_device *dev = qdisc_dev(sch);
return netdev_get_tx_queue(dev, 0);
return dev_queue;
static int mq_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new,
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