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![Jakub Kicinski](/assets/img/avatar_default.png)
Drivers offloading Qdiscs should have reasonable certainty the offloaded behaviour matches the SW path. This is impossible if the driver does not know about all Qdiscs or when Qdiscs move and are reused. Send a graft notification from MQ. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: John Hurley <john.hurley@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
294 lines
7.3 KiB
C
294 lines
7.3 KiB
C
/*
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* net/sched/sch_mq.c Classful multiqueue dummy scheduler
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*
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* Copyright (c) 2009 Patrick McHardy <kaber@trash.net>
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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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* version 2 as published by the Free Software Foundation.
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*/
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#include <linux/types.h>
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#include <linux/slab.h>
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#include <linux/kernel.h>
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#include <linux/export.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_cls.h>
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#include <net/pkt_sched.h>
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#include <net/sch_generic.h>
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struct mq_sched {
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struct Qdisc **qdiscs;
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};
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static int mq_offload(struct Qdisc *sch, enum tc_mq_command cmd)
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{
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struct net_device *dev = qdisc_dev(sch);
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struct tc_mq_qopt_offload opt = {
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.command = cmd,
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.handle = sch->handle,
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};
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if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
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return -EOPNOTSUPP;
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return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_MQ, &opt);
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}
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static int mq_offload_stats(struct Qdisc *sch)
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{
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struct tc_mq_qopt_offload opt = {
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.command = TC_MQ_STATS,
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.handle = sch->handle,
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.stats = {
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.bstats = &sch->bstats,
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.qstats = &sch->qstats,
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},
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};
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return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_MQ, &opt);
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}
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static void mq_destroy(struct Qdisc *sch)
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{
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struct net_device *dev = qdisc_dev(sch);
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struct mq_sched *priv = qdisc_priv(sch);
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unsigned int ntx;
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mq_offload(sch, TC_MQ_DESTROY);
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if (!priv->qdiscs)
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return;
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for (ntx = 0; ntx < dev->num_tx_queues && priv->qdiscs[ntx]; ntx++)
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qdisc_put(priv->qdiscs[ntx]);
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kfree(priv->qdiscs);
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}
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static int mq_init(struct Qdisc *sch, struct nlattr *opt,
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struct netlink_ext_ack *extack)
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{
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struct net_device *dev = qdisc_dev(sch);
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struct mq_sched *priv = qdisc_priv(sch);
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struct netdev_queue *dev_queue;
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struct Qdisc *qdisc;
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unsigned int ntx;
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if (sch->parent != TC_H_ROOT)
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return -EOPNOTSUPP;
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if (!netif_is_multiqueue(dev))
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return -EOPNOTSUPP;
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/* pre-allocate qdiscs, attachment can't fail */
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priv->qdiscs = kcalloc(dev->num_tx_queues, sizeof(priv->qdiscs[0]),
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GFP_KERNEL);
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if (!priv->qdiscs)
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return -ENOMEM;
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for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
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dev_queue = netdev_get_tx_queue(dev, ntx);
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qdisc = qdisc_create_dflt(dev_queue, get_default_qdisc_ops(dev, ntx),
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TC_H_MAKE(TC_H_MAJ(sch->handle),
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TC_H_MIN(ntx + 1)),
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extack);
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if (!qdisc)
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return -ENOMEM;
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priv->qdiscs[ntx] = qdisc;
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qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
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}
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sch->flags |= TCQ_F_MQROOT;
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mq_offload(sch, TC_MQ_CREATE);
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return 0;
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}
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static void mq_attach(struct Qdisc *sch)
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{
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struct net_device *dev = qdisc_dev(sch);
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struct mq_sched *priv = qdisc_priv(sch);
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struct Qdisc *qdisc, *old;
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unsigned int ntx;
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for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
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qdisc = priv->qdiscs[ntx];
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old = dev_graft_qdisc(qdisc->dev_queue, qdisc);
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if (old)
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qdisc_put(old);
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#ifdef CONFIG_NET_SCHED
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if (ntx < dev->real_num_tx_queues)
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qdisc_hash_add(qdisc, false);
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#endif
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}
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kfree(priv->qdiscs);
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priv->qdiscs = NULL;
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}
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static int mq_dump(struct Qdisc *sch, struct sk_buff *skb)
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{
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struct net_device *dev = qdisc_dev(sch);
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struct Qdisc *qdisc;
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unsigned int ntx;
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__u32 qlen = 0;
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sch->q.qlen = 0;
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memset(&sch->bstats, 0, sizeof(sch->bstats));
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memset(&sch->qstats, 0, sizeof(sch->qstats));
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/* MQ supports lockless qdiscs. However, statistics accounting needs
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* to account for all, none, or a mix of locked and unlocked child
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* qdiscs. Percpu stats are added to counters in-band and locking
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* qdisc totals are added at end.
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*/
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for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
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qdisc = netdev_get_tx_queue(dev, ntx)->qdisc_sleeping;
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spin_lock_bh(qdisc_lock(qdisc));
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if (qdisc_is_percpu_stats(qdisc)) {
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qlen = qdisc_qlen_sum(qdisc);
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__gnet_stats_copy_basic(NULL, &sch->bstats,
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qdisc->cpu_bstats,
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&qdisc->bstats);
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__gnet_stats_copy_queue(&sch->qstats,
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qdisc->cpu_qstats,
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&qdisc->qstats, qlen);
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} else {
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sch->q.qlen += qdisc->q.qlen;
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sch->bstats.bytes += qdisc->bstats.bytes;
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sch->bstats.packets += qdisc->bstats.packets;
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sch->qstats.qlen += qdisc->qstats.qlen;
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sch->qstats.backlog += qdisc->qstats.backlog;
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sch->qstats.drops += qdisc->qstats.drops;
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sch->qstats.requeues += qdisc->qstats.requeues;
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sch->qstats.overlimits += qdisc->qstats.overlimits;
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}
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spin_unlock_bh(qdisc_lock(qdisc));
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}
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return mq_offload_stats(sch);
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}
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static struct netdev_queue *mq_queue_get(struct Qdisc *sch, unsigned long cl)
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{
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struct net_device *dev = qdisc_dev(sch);
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unsigned long ntx = cl - 1;
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if (ntx >= dev->num_tx_queues)
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return NULL;
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return netdev_get_tx_queue(dev, ntx);
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}
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static struct netdev_queue *mq_select_queue(struct Qdisc *sch,
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struct tcmsg *tcm)
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{
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return mq_queue_get(sch, TC_H_MIN(tcm->tcm_parent));
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}
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static int mq_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new,
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struct Qdisc **old, struct netlink_ext_ack *extack)
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{
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struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
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struct tc_mq_qopt_offload graft_offload;
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struct net_device *dev = qdisc_dev(sch);
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if (dev->flags & IFF_UP)
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dev_deactivate(dev);
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*old = dev_graft_qdisc(dev_queue, new);
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if (new)
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new->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
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if (dev->flags & IFF_UP)
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dev_activate(dev);
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graft_offload.handle = sch->handle;
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graft_offload.graft_params.queue = cl - 1;
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graft_offload.graft_params.child_handle = new ? new->handle : 0;
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graft_offload.command = TC_MQ_GRAFT;
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qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, *old,
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TC_SETUP_QDISC_MQ, &graft_offload, extack);
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return 0;
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}
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static struct Qdisc *mq_leaf(struct Qdisc *sch, unsigned long cl)
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{
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struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
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return dev_queue->qdisc_sleeping;
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}
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static unsigned long mq_find(struct Qdisc *sch, u32 classid)
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{
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unsigned int ntx = TC_H_MIN(classid);
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if (!mq_queue_get(sch, ntx))
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return 0;
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return ntx;
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}
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static int mq_dump_class(struct Qdisc *sch, unsigned long cl,
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struct sk_buff *skb, struct tcmsg *tcm)
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{
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struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
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tcm->tcm_parent = TC_H_ROOT;
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tcm->tcm_handle |= TC_H_MIN(cl);
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tcm->tcm_info = dev_queue->qdisc_sleeping->handle;
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return 0;
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}
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static int mq_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 netdev_queue *dev_queue = mq_queue_get(sch, cl);
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sch = dev_queue->qdisc_sleeping;
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if (gnet_stats_copy_basic(&sch->running, d, NULL, &sch->bstats) < 0 ||
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gnet_stats_copy_queue(d, NULL, &sch->qstats, sch->q.qlen) < 0)
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return -1;
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return 0;
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}
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static void mq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
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{
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struct net_device *dev = qdisc_dev(sch);
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unsigned int ntx;
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if (arg->stop)
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return;
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arg->count = arg->skip;
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for (ntx = arg->skip; ntx < dev->num_tx_queues; ntx++) {
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if (arg->fn(sch, ntx + 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 const struct Qdisc_class_ops mq_class_ops = {
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.select_queue = mq_select_queue,
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.graft = mq_graft,
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.leaf = mq_leaf,
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.find = mq_find,
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.walk = mq_walk,
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.dump = mq_dump_class,
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.dump_stats = mq_dump_class_stats,
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};
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struct Qdisc_ops mq_qdisc_ops __read_mostly = {
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.cl_ops = &mq_class_ops,
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.id = "mq",
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.priv_size = sizeof(struct mq_sched),
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.init = mq_init,
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.destroy = mq_destroy,
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.attach = mq_attach,
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.dump = mq_dump,
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.owner = THIS_MODULE,
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};
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