![Lucas Nussbaum](/assets/img/avatar_default.png)
When CONFIG_NET_CLS_ACT is enabled, tc_classify() is called twice in
prio_classify(). This causes "interesting" behaviour: with the setup
below, packets are duplicated, sent twice to ifb0, and then loop in and
out of ifb0.
The patch uses the previously calculated return value in the switch,
which is probably what Patrick had in mind in commit
bdba91ec70
-- maybe Patrick can
double-check this?
-- example setup --
ifconfig ifb0 up
tc qdisc add dev ifb0 root netem delay 2s
tc qdisc add dev $ETH root handle 1: prio
tc filter add dev $ETH parent 1: protocol ip prio 10 u32 \
match ip dst 172.24.110.6/32 flowid 1:1 \
action mirred egress redirect dev ifb0
ping -c1 172.24.110.6
Signed-off-by: Lucas Nussbaum <lucas.nussbaum@imag.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
544 lines
12 KiB
C
544 lines
12 KiB
C
/*
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* net/sched/sch_prio.c Simple 3-band priority "scheduler".
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
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* Fixes: 19990609: J Hadi Salim <hadi@nortelnetworks.com>:
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* Init -- EINVAL when opt undefined
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/errno.h>
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#include <linux/skbuff.h>
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#include <net/netlink.h>
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#include <net/pkt_sched.h>
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struct prio_sched_data
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{
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int bands;
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int curband; /* for round-robin */
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struct tcf_proto *filter_list;
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u8 prio2band[TC_PRIO_MAX+1];
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struct Qdisc *queues[TCQ_PRIO_BANDS];
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int mq;
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};
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static struct Qdisc *
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prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
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{
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struct prio_sched_data *q = qdisc_priv(sch);
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u32 band = skb->priority;
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struct tcf_result res;
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int err;
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*qerr = NET_XMIT_BYPASS;
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if (TC_H_MAJ(skb->priority) != sch->handle) {
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err = tc_classify(skb, q->filter_list, &res);
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#ifdef CONFIG_NET_CLS_ACT
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switch (err) {
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case TC_ACT_STOLEN:
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case TC_ACT_QUEUED:
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*qerr = NET_XMIT_SUCCESS;
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case TC_ACT_SHOT:
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return NULL;
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}
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#endif
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if (!q->filter_list || err < 0) {
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if (TC_H_MAJ(band))
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band = 0;
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band = q->prio2band[band&TC_PRIO_MAX];
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goto out;
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}
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band = res.classid;
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}
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band = TC_H_MIN(band) - 1;
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if (band >= q->bands)
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band = q->prio2band[0];
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out:
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if (q->mq)
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skb_set_queue_mapping(skb, band);
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return q->queues[band];
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}
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static int
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prio_enqueue(struct sk_buff *skb, struct Qdisc *sch)
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{
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struct Qdisc *qdisc;
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int ret;
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qdisc = prio_classify(skb, sch, &ret);
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#ifdef CONFIG_NET_CLS_ACT
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if (qdisc == NULL) {
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if (ret == NET_XMIT_BYPASS)
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sch->qstats.drops++;
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kfree_skb(skb);
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return ret;
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}
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#endif
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if ((ret = qdisc->enqueue(skb, qdisc)) == NET_XMIT_SUCCESS) {
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sch->bstats.bytes += skb->len;
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sch->bstats.packets++;
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sch->q.qlen++;
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return NET_XMIT_SUCCESS;
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}
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sch->qstats.drops++;
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return ret;
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}
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static int
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prio_requeue(struct sk_buff *skb, struct Qdisc* sch)
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{
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struct Qdisc *qdisc;
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int ret;
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qdisc = prio_classify(skb, sch, &ret);
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#ifdef CONFIG_NET_CLS_ACT
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if (qdisc == NULL) {
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if (ret == NET_XMIT_BYPASS)
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sch->qstats.drops++;
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kfree_skb(skb);
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return ret;
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}
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#endif
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if ((ret = qdisc->ops->requeue(skb, qdisc)) == NET_XMIT_SUCCESS) {
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sch->q.qlen++;
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sch->qstats.requeues++;
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return 0;
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}
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sch->qstats.drops++;
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return NET_XMIT_DROP;
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}
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static struct sk_buff *
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prio_dequeue(struct Qdisc* sch)
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{
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struct sk_buff *skb;
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struct prio_sched_data *q = qdisc_priv(sch);
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int prio;
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struct Qdisc *qdisc;
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for (prio = 0; prio < q->bands; prio++) {
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/* Check if the target subqueue is available before
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* pulling an skb. This way we avoid excessive requeues
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* for slower queues.
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*/
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if (!netif_subqueue_stopped(sch->dev, (q->mq ? prio : 0))) {
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qdisc = q->queues[prio];
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skb = qdisc->dequeue(qdisc);
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if (skb) {
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sch->q.qlen--;
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return skb;
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}
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}
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}
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return NULL;
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}
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static struct sk_buff *rr_dequeue(struct Qdisc* sch)
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{
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struct sk_buff *skb;
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struct prio_sched_data *q = qdisc_priv(sch);
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struct Qdisc *qdisc;
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int bandcount;
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/* Only take one pass through the queues. If nothing is available,
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* return nothing.
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*/
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for (bandcount = 0; bandcount < q->bands; bandcount++) {
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/* Check if the target subqueue is available before
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* pulling an skb. This way we avoid excessive requeues
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* for slower queues. If the queue is stopped, try the
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* next queue.
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*/
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if (!netif_subqueue_stopped(sch->dev,
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(q->mq ? q->curband : 0))) {
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qdisc = q->queues[q->curband];
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skb = qdisc->dequeue(qdisc);
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if (skb) {
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sch->q.qlen--;
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q->curband++;
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if (q->curband >= q->bands)
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q->curband = 0;
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return skb;
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}
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}
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q->curband++;
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if (q->curband >= q->bands)
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q->curband = 0;
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}
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return NULL;
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}
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static unsigned int prio_drop(struct Qdisc* sch)
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{
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struct prio_sched_data *q = qdisc_priv(sch);
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int prio;
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unsigned int len;
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struct Qdisc *qdisc;
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for (prio = q->bands-1; prio >= 0; prio--) {
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qdisc = q->queues[prio];
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if (qdisc->ops->drop && (len = qdisc->ops->drop(qdisc)) != 0) {
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sch->q.qlen--;
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return len;
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}
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}
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return 0;
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}
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static void
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prio_reset(struct Qdisc* sch)
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{
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int prio;
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struct prio_sched_data *q = qdisc_priv(sch);
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for (prio=0; prio<q->bands; prio++)
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qdisc_reset(q->queues[prio]);
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sch->q.qlen = 0;
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}
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static void
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prio_destroy(struct Qdisc* sch)
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{
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int prio;
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struct prio_sched_data *q = qdisc_priv(sch);
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tcf_destroy_chain(q->filter_list);
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for (prio=0; prio<q->bands; prio++)
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qdisc_destroy(q->queues[prio]);
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}
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static int prio_tune(struct Qdisc *sch, struct rtattr *opt)
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{
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struct prio_sched_data *q = qdisc_priv(sch);
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struct tc_prio_qopt *qopt;
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struct rtattr *tb[TCA_PRIO_MAX];
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int i;
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if (rtattr_parse_nested_compat(tb, TCA_PRIO_MAX, opt, qopt,
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sizeof(*qopt)))
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return -EINVAL;
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q->bands = qopt->bands;
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/* If we're multiqueue, make sure the number of incoming bands
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* matches the number of queues on the device we're associating with.
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* If the number of bands requested is zero, then set q->bands to
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* dev->egress_subqueue_count. Also, the root qdisc must be the
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* only one that is enabled for multiqueue, since it's the only one
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* that interacts with the underlying device.
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*/
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q->mq = RTA_GET_FLAG(tb[TCA_PRIO_MQ - 1]);
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if (q->mq) {
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if (sch->parent != TC_H_ROOT)
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return -EINVAL;
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if (netif_is_multiqueue(sch->dev)) {
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if (q->bands == 0)
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q->bands = sch->dev->egress_subqueue_count;
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else if (q->bands != sch->dev->egress_subqueue_count)
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return -EINVAL;
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} else
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return -EOPNOTSUPP;
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}
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if (q->bands > TCQ_PRIO_BANDS || q->bands < 2)
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return -EINVAL;
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for (i=0; i<=TC_PRIO_MAX; i++) {
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if (qopt->priomap[i] >= q->bands)
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return -EINVAL;
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}
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sch_tree_lock(sch);
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memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
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for (i=q->bands; i<TCQ_PRIO_BANDS; i++) {
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struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc);
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if (child != &noop_qdisc) {
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qdisc_tree_decrease_qlen(child, child->q.qlen);
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qdisc_destroy(child);
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}
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}
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sch_tree_unlock(sch);
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for (i=0; i<q->bands; i++) {
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if (q->queues[i] == &noop_qdisc) {
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struct Qdisc *child;
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child = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops,
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TC_H_MAKE(sch->handle, i + 1));
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if (child) {
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sch_tree_lock(sch);
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child = xchg(&q->queues[i], child);
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if (child != &noop_qdisc) {
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qdisc_tree_decrease_qlen(child,
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child->q.qlen);
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qdisc_destroy(child);
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}
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sch_tree_unlock(sch);
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}
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}
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}
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return 0;
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}
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static int prio_init(struct Qdisc *sch, struct rtattr *opt)
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{
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struct prio_sched_data *q = qdisc_priv(sch);
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int i;
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for (i=0; i<TCQ_PRIO_BANDS; i++)
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q->queues[i] = &noop_qdisc;
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if (opt == NULL) {
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return -EINVAL;
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} else {
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int err;
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if ((err= prio_tune(sch, opt)) != 0)
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return err;
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}
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return 0;
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}
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static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
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{
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struct prio_sched_data *q = qdisc_priv(sch);
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unsigned char *b = skb_tail_pointer(skb);
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struct rtattr *nest;
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struct tc_prio_qopt opt;
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opt.bands = q->bands;
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memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX+1);
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nest = RTA_NEST_COMPAT(skb, TCA_OPTIONS, sizeof(opt), &opt);
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if (q->mq)
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RTA_PUT_FLAG(skb, TCA_PRIO_MQ);
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RTA_NEST_COMPAT_END(skb, nest);
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return skb->len;
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rtattr_failure:
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nlmsg_trim(skb, b);
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return -1;
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}
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static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
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struct Qdisc **old)
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{
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struct prio_sched_data *q = qdisc_priv(sch);
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unsigned long band = arg - 1;
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if (band >= q->bands)
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return -EINVAL;
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if (new == NULL)
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new = &noop_qdisc;
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sch_tree_lock(sch);
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*old = q->queues[band];
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q->queues[band] = new;
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qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
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qdisc_reset(*old);
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sch_tree_unlock(sch);
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return 0;
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}
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static struct Qdisc *
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prio_leaf(struct Qdisc *sch, unsigned long arg)
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{
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struct prio_sched_data *q = qdisc_priv(sch);
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unsigned long band = arg - 1;
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if (band >= q->bands)
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return NULL;
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return q->queues[band];
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}
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static unsigned long prio_get(struct Qdisc *sch, u32 classid)
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{
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struct prio_sched_data *q = qdisc_priv(sch);
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unsigned long band = TC_H_MIN(classid);
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if (band - 1 >= q->bands)
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return 0;
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return band;
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}
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static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
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{
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return prio_get(sch, classid);
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}
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static void prio_put(struct Qdisc *q, unsigned long cl)
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{
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return;
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}
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static int prio_change(struct Qdisc *sch, u32 handle, u32 parent, struct rtattr **tca, unsigned long *arg)
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{
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unsigned long cl = *arg;
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struct prio_sched_data *q = qdisc_priv(sch);
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if (cl - 1 > q->bands)
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return -ENOENT;
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return 0;
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}
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static int prio_delete(struct Qdisc *sch, unsigned long cl)
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{
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struct prio_sched_data *q = qdisc_priv(sch);
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if (cl - 1 > q->bands)
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return -ENOENT;
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return 0;
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}
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static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
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struct tcmsg *tcm)
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{
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struct prio_sched_data *q = qdisc_priv(sch);
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if (cl - 1 > q->bands)
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return -ENOENT;
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tcm->tcm_handle |= TC_H_MIN(cl);
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if (q->queues[cl-1])
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tcm->tcm_info = q->queues[cl-1]->handle;
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return 0;
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}
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static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
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struct gnet_dump *d)
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{
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struct prio_sched_data *q = qdisc_priv(sch);
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struct Qdisc *cl_q;
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cl_q = q->queues[cl - 1];
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if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
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gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
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return -1;
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return 0;
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}
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static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
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{
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struct prio_sched_data *q = qdisc_priv(sch);
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int prio;
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if (arg->stop)
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return;
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for (prio = 0; prio < q->bands; prio++) {
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if (arg->count < arg->skip) {
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arg->count++;
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continue;
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}
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if (arg->fn(sch, prio+1, arg) < 0) {
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arg->stop = 1;
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break;
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}
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arg->count++;
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}
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}
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static struct tcf_proto ** prio_find_tcf(struct Qdisc *sch, unsigned long cl)
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{
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struct prio_sched_data *q = qdisc_priv(sch);
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if (cl)
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return NULL;
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return &q->filter_list;
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}
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static struct Qdisc_class_ops prio_class_ops = {
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.graft = prio_graft,
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.leaf = prio_leaf,
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.get = prio_get,
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.put = prio_put,
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.change = prio_change,
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.delete = prio_delete,
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.walk = prio_walk,
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.tcf_chain = prio_find_tcf,
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.bind_tcf = prio_bind,
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.unbind_tcf = prio_put,
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.dump = prio_dump_class,
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.dump_stats = prio_dump_class_stats,
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};
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static struct Qdisc_ops prio_qdisc_ops = {
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.next = NULL,
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.cl_ops = &prio_class_ops,
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.id = "prio",
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.priv_size = sizeof(struct prio_sched_data),
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.enqueue = prio_enqueue,
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.dequeue = prio_dequeue,
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.requeue = prio_requeue,
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.drop = prio_drop,
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.init = prio_init,
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.reset = prio_reset,
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.destroy = prio_destroy,
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.change = prio_tune,
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.dump = prio_dump,
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.owner = THIS_MODULE,
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};
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static struct Qdisc_ops rr_qdisc_ops = {
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.next = NULL,
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.cl_ops = &prio_class_ops,
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.id = "rr",
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.priv_size = sizeof(struct prio_sched_data),
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.enqueue = prio_enqueue,
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.dequeue = rr_dequeue,
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.requeue = prio_requeue,
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.drop = prio_drop,
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.init = prio_init,
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.reset = prio_reset,
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.destroy = prio_destroy,
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.change = prio_tune,
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.dump = prio_dump,
|
|
.owner = THIS_MODULE,
|
|
};
|
|
|
|
static int __init prio_module_init(void)
|
|
{
|
|
int err;
|
|
|
|
err = register_qdisc(&prio_qdisc_ops);
|
|
if (err < 0)
|
|
return err;
|
|
err = register_qdisc(&rr_qdisc_ops);
|
|
if (err < 0)
|
|
unregister_qdisc(&prio_qdisc_ops);
|
|
return err;
|
|
}
|
|
|
|
static void __exit prio_module_exit(void)
|
|
{
|
|
unregister_qdisc(&prio_qdisc_ops);
|
|
unregister_qdisc(&rr_qdisc_ops);
|
|
}
|
|
|
|
module_init(prio_module_init)
|
|
module_exit(prio_module_exit)
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("sch_rr");
|