// SPDX-License-Identifier: GPL-2.0-only
/*
 * net/sched/sch_mqprio.c
 *
 * Copyright (c) 2010 John Fastabend <john.r.fastabend@intel.com>
 */

#include <linux/ethtool_netlink.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
#include <linux/module.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <net/sch_generic.h>
#include <net/pkt_cls.h>

#include "sch_mqprio_lib.h"

struct mqprio_sched {
        struct Qdisc            **qdiscs;
        u16 mode;
        u16 shaper;
        int hw_offload;
        u32 flags;
        u64 min_rate[TC_QOPT_MAX_QUEUE];
        u64 max_rate[TC_QOPT_MAX_QUEUE];
        u32 fp[TC_QOPT_MAX_QUEUE];
};

static int mqprio_enable_offload(struct Qdisc *sch,
                                 const struct tc_mqprio_qopt *qopt,
                                 struct netlink_ext_ack *extack)
{
        struct mqprio_sched *priv = qdisc_priv(sch);
        struct net_device *dev = qdisc_dev(sch);
        struct tc_mqprio_qopt_offload mqprio = {
                .qopt = *qopt,
                .extack = extack,
        };
        int err, i;

        switch (priv->mode) {
        case TC_MQPRIO_MODE_DCB:
                if (priv->shaper != TC_MQPRIO_SHAPER_DCB)
                        return -EINVAL;
                break;
        case TC_MQPRIO_MODE_CHANNEL:
                mqprio.flags = priv->flags;
                if (priv->flags & TC_MQPRIO_F_MODE)
                        mqprio.mode = priv->mode;
                if (priv->flags & TC_MQPRIO_F_SHAPER)
                        mqprio.shaper = priv->shaper;
                if (priv->flags & TC_MQPRIO_F_MIN_RATE)
                        for (i = 0; i < mqprio.qopt.num_tc; i++)
                                mqprio.min_rate[i] = priv->min_rate[i];
                if (priv->flags & TC_MQPRIO_F_MAX_RATE)
                        for (i = 0; i < mqprio.qopt.num_tc; i++)
                                mqprio.max_rate[i] = priv->max_rate[i];
                break;
        default:
                return -EINVAL;
        }

        mqprio_fp_to_offload(priv->fp, &mqprio);

        err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_MQPRIO,
                                            &mqprio);
        if (err)
                return err;

        priv->hw_offload = mqprio.qopt.hw;

        return 0;
}

static void mqprio_disable_offload(struct Qdisc *sch)
{
        struct tc_mqprio_qopt_offload mqprio = { { 0 } };
        struct mqprio_sched *priv = qdisc_priv(sch);
        struct net_device *dev = qdisc_dev(sch);

        switch (priv->mode) {
        case TC_MQPRIO_MODE_DCB:
        case TC_MQPRIO_MODE_CHANNEL:
                dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_MQPRIO,
                                              &mqprio);
                break;
        }
}

static void mqprio_destroy(struct Qdisc *sch)
{
        struct net_device *dev = qdisc_dev(sch);
        struct mqprio_sched *priv = qdisc_priv(sch);
        unsigned int ntx;

        if (priv->qdiscs) {
                for (ntx = 0;
                     ntx < dev->num_tx_queues && priv->qdiscs[ntx];
                     ntx++)
                        qdisc_put(priv->qdiscs[ntx]);
                kfree(priv->qdiscs);
        }

        if (priv->hw_offload && dev->netdev_ops->ndo_setup_tc)
                mqprio_disable_offload(sch);
        else
                netdev_set_num_tc(dev, 0);
}

static int mqprio_parse_opt(struct net_device *dev, struct tc_mqprio_qopt *qopt,
                            const struct tc_mqprio_caps *caps,
                            struct netlink_ext_ack *extack)
{
        int err;

        /* Limit qopt->hw to maximum supported offload value.  Drivers have
         * the option of overriding this later if they don't support the a
         * given offload type.
         */
        if (qopt->hw > TC_MQPRIO_HW_OFFLOAD_MAX)
                qopt->hw = TC_MQPRIO_HW_OFFLOAD_MAX;

        /* If hardware offload is requested, we will leave 3 options to the
         * device driver:
         * - populate the queue counts itself (and ignore what was requested)
         * - validate the provided queue counts by itself (and apply them)
         * - request queue count validation here (and apply them)
         */
        err = mqprio_validate_qopt(dev, qopt,
                                   !qopt->hw || caps->validate_queue_counts,
                                   false, extack);
        if (err)
                return err;

        /* If ndo_setup_tc is not present then hardware doesn't support offload
         * and we should return an error.
         */
        if (qopt->hw && !dev->netdev_ops->ndo_setup_tc) {
                NL_SET_ERR_MSG(extack,
                               "Device does not support hardware offload");
                return -EINVAL;
        }

        return 0;
}

static const struct
nla_policy mqprio_tc_entry_policy[TCA_MQPRIO_TC_ENTRY_MAX + 1] = {
        [TCA_MQPRIO_TC_ENTRY_INDEX]     = NLA_POLICY_MAX(NLA_U32,
                                                         TC_QOPT_MAX_QUEUE - 1),
        [TCA_MQPRIO_TC_ENTRY_FP]        = NLA_POLICY_RANGE(NLA_U32,
                                                           TC_FP_EXPRESS,
                                                           TC_FP_PREEMPTIBLE),
};

static const struct nla_policy mqprio_policy[TCA_MQPRIO_MAX + 1] = {
        [TCA_MQPRIO_MODE]       = { .len = sizeof(u16) },
        [TCA_MQPRIO_SHAPER]     = { .len = sizeof(u16) },
        [TCA_MQPRIO_MIN_RATE64] = { .type = NLA_NESTED },
        [TCA_MQPRIO_MAX_RATE64] = { .type = NLA_NESTED },
        [TCA_MQPRIO_TC_ENTRY]   = { .type = NLA_NESTED },
};

static int mqprio_parse_tc_entry(u32 fp[TC_QOPT_MAX_QUEUE],
                                 struct nlattr *opt,
                                 unsigned long *seen_tcs,
                                 struct netlink_ext_ack *extack)
{
        struct nlattr *tb[TCA_MQPRIO_TC_ENTRY_MAX + 1];
        int err, tc;

        err = nla_parse_nested(tb, TCA_MQPRIO_TC_ENTRY_MAX, opt,
                               mqprio_tc_entry_policy, extack);
        if (err < 0)
                return err;

        if (NL_REQ_ATTR_CHECK(extack, opt, tb, TCA_MQPRIO_TC_ENTRY_INDEX)) {
                NL_SET_ERR_MSG(extack, "TC entry index missing");
                return -EINVAL;
        }

        tc = nla_get_u32(tb[TCA_MQPRIO_TC_ENTRY_INDEX]);
        if (*seen_tcs & BIT(tc)) {
                NL_SET_ERR_MSG_ATTR(extack, tb[TCA_MQPRIO_TC_ENTRY_INDEX],
                                    "Duplicate tc entry");
                return -EINVAL;
        }

        *seen_tcs |= BIT(tc);

        if (tb[TCA_MQPRIO_TC_ENTRY_FP])
                fp[tc] = nla_get_u32(tb[TCA_MQPRIO_TC_ENTRY_FP]);

        return 0;
}

static int mqprio_parse_tc_entries(struct Qdisc *sch, struct nlattr *nlattr_opt,
                                   int nlattr_opt_len,
                                   struct netlink_ext_ack *extack)
{
        struct mqprio_sched *priv = qdisc_priv(sch);
        struct net_device *dev = qdisc_dev(sch);
        bool have_preemption = false;
        unsigned long seen_tcs = 0;
        u32 fp[TC_QOPT_MAX_QUEUE];
        struct nlattr *n;
        int tc, rem;
        int err = 0;

        for (tc = 0; tc < TC_QOPT_MAX_QUEUE; tc++)
                fp[tc] = priv->fp[tc];

        nla_for_each_attr_type(n, TCA_MQPRIO_TC_ENTRY, nlattr_opt,
                               nlattr_opt_len, rem) {
                err = mqprio_parse_tc_entry(fp, n, &seen_tcs, extack);
                if (err)
                        goto out;
        }

        for (tc = 0; tc < TC_QOPT_MAX_QUEUE; tc++) {
                priv->fp[tc] = fp[tc];
                if (fp[tc] == TC_FP_PREEMPTIBLE)
                        have_preemption = true;
        }

        if (have_preemption && !ethtool_dev_mm_supported(dev)) {
                NL_SET_ERR_MSG(extack, "Device does not support preemption");
                return -EOPNOTSUPP;
        }
out:
        return err;
}

/* Parse the other netlink attributes that represent the payload of
 * TCA_OPTIONS, which are appended right after struct tc_mqprio_qopt.
 */
static int mqprio_parse_nlattr(struct Qdisc *sch, struct tc_mqprio_qopt *qopt,
                               struct nlattr *opt,
                               struct netlink_ext_ack *extack)
{
        struct nlattr *nlattr_opt = nla_data(opt) + NLA_ALIGN(sizeof(*qopt));
        int nlattr_opt_len = nla_len(opt) - NLA_ALIGN(sizeof(*qopt));
        struct mqprio_sched *priv = qdisc_priv(sch);
        struct nlattr *tb[TCA_MQPRIO_MAX + 1] = {};
        struct nlattr *attr;
        int i, rem, err;

        if (nlattr_opt_len >= nla_attr_size(0)) {
                err = nla_parse_deprecated(tb, TCA_MQPRIO_MAX, nlattr_opt,
                                           nlattr_opt_len, mqprio_policy,
                                           NULL);
                if (err < 0)
                        return err;
        }

        if (!qopt->hw) {
                NL_SET_ERR_MSG(extack,
                               "mqprio TCA_OPTIONS can only contain netlink attributes in hardware mode");
                return -EINVAL;
        }

        if (tb[TCA_MQPRIO_MODE]) {
                priv->flags |= TC_MQPRIO_F_MODE;
                priv->mode = nla_get_u16(tb[TCA_MQPRIO_MODE]);
        }

        if (tb[TCA_MQPRIO_SHAPER]) {
                priv->flags |= TC_MQPRIO_F_SHAPER;
                priv->shaper = nla_get_u16(tb[TCA_MQPRIO_SHAPER]);
        }

        if (tb[TCA_MQPRIO_MIN_RATE64]) {
                if (priv->shaper != TC_MQPRIO_SHAPER_BW_RATE) {
                        NL_SET_ERR_MSG_ATTR(extack, tb[TCA_MQPRIO_MIN_RATE64],
                                            "min_rate accepted only when shaper is in bw_rlimit mode");
                        return -EINVAL;
                }
                i = 0;
                nla_for_each_nested(attr, tb[TCA_MQPRIO_MIN_RATE64],
                                    rem) {
                        if (nla_type(attr) != TCA_MQPRIO_MIN_RATE64) {
                                NL_SET_ERR_MSG_ATTR(extack, attr,
                                                    "Attribute type expected to be TCA_MQPRIO_MIN_RATE64");
                                return -EINVAL;
                        }

                        if (nla_len(attr) != sizeof(u64)) {
                                NL_SET_ERR_MSG_ATTR(extack, attr,
                                                    "Attribute TCA_MQPRIO_MIN_RATE64 expected to have 8 bytes length");
                                return -EINVAL;
                        }

                        if (i >= qopt->num_tc)
                                break;
                        priv->min_rate[i] = nla_get_u64(attr);
                        i++;
                }
                priv->flags |= TC_MQPRIO_F_MIN_RATE;
        }

        if (tb[TCA_MQPRIO_MAX_RATE64]) {
                if (priv->shaper != TC_MQPRIO_SHAPER_BW_RATE) {
                        NL_SET_ERR_MSG_ATTR(extack, tb[TCA_MQPRIO_MAX_RATE64],
                                            "max_rate accepted only when shaper is in bw_rlimit mode");
                        return -EINVAL;
                }
                i = 0;
                nla_for_each_nested(attr, tb[TCA_MQPRIO_MAX_RATE64],
                                    rem) {
                        if (nla_type(attr) != TCA_MQPRIO_MAX_RATE64) {
                                NL_SET_ERR_MSG_ATTR(extack, attr,
                                                    "Attribute type expected to be TCA_MQPRIO_MAX_RATE64");
                                return -EINVAL;
                        }

                        if (nla_len(attr) != sizeof(u64)) {
                                NL_SET_ERR_MSG_ATTR(extack, attr,
                                                    "Attribute TCA_MQPRIO_MAX_RATE64 expected to have 8 bytes length");
                                return -EINVAL;
                        }

                        if (i >= qopt->num_tc)
                                break;
                        priv->max_rate[i] = nla_get_u64(attr);
                        i++;
                }
                priv->flags |= TC_MQPRIO_F_MAX_RATE;
        }

        if (tb[TCA_MQPRIO_TC_ENTRY]) {
                err = mqprio_parse_tc_entries(sch, nlattr_opt, nlattr_opt_len,
                                              extack);
                if (err)
                        return err;
        }

        return 0;
}

static int mqprio_init(struct Qdisc *sch, struct nlattr *opt,
                       struct netlink_ext_ack *extack)
{
        struct net_device *dev = qdisc_dev(sch);
        struct mqprio_sched *priv = qdisc_priv(sch);
        struct netdev_queue *dev_queue;
        struct Qdisc *qdisc;
        int i, err = -EOPNOTSUPP;
        struct tc_mqprio_qopt *qopt = NULL;
        struct tc_mqprio_caps caps;
        int len, tc;

        BUILD_BUG_ON(TC_MAX_QUEUE != TC_QOPT_MAX_QUEUE);
        BUILD_BUG_ON(TC_BITMASK != TC_QOPT_BITMASK);

        if (sch->parent != TC_H_ROOT)
                return -EOPNOTSUPP;

        if (!netif_is_multiqueue(dev))
                return -EOPNOTSUPP;

        /* make certain can allocate enough classids to handle queues */
        if (dev->num_tx_queues >= TC_H_MIN_PRIORITY)
                return -ENOMEM;

        if (!opt || nla_len(opt) < sizeof(*qopt))
                return -EINVAL;

        for (tc = 0; tc < TC_QOPT_MAX_QUEUE; tc++)
                priv->fp[tc] = TC_FP_EXPRESS;

        qdisc_offload_query_caps(dev, TC_SETUP_QDISC_MQPRIO,
                                 &caps, sizeof(caps));

        qopt = nla_data(opt);
        if (mqprio_parse_opt(dev, qopt, &caps, extack))
                return -EINVAL;

        len = nla_len(opt) - NLA_ALIGN(sizeof(*qopt));
        if (len > 0) {
                err = mqprio_parse_nlattr(sch, qopt, opt, extack);
                if (err)
                        return err;
        }

        /* pre-allocate qdisc, attachment can't fail */
        priv->qdiscs = kzalloc_objs(priv->qdiscs[0], dev->num_tx_queues);
        if (!priv->qdiscs)
                return -ENOMEM;

        for (i = 0; i < dev->num_tx_queues; i++) {
                dev_queue = netdev_get_tx_queue(dev, i);
                qdisc = qdisc_create_dflt(dev_queue,
                                          get_default_qdisc_ops(dev, i),
                                          TC_H_MAKE(TC_H_MAJ(sch->handle),
                                                    TC_H_MIN(i + 1)), extack);
                if (!qdisc)
                        return -ENOMEM;

                priv->qdiscs[i] = qdisc;
                qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
        }

        /* If the mqprio options indicate that hardware should own
         * the queue mapping then run ndo_setup_tc otherwise use the
         * supplied and verified mapping
         */
        if (qopt->hw) {
                err = mqprio_enable_offload(sch, qopt, extack);
                if (err)
                        return err;
        } else {
                netdev_set_num_tc(dev, qopt->num_tc);
                for (i = 0; i < qopt->num_tc; i++)
                        netdev_set_tc_queue(dev, i,
                                            qopt->count[i], qopt->offset[i]);
        }

        /* Always use supplied priority mappings */
        for (i = 0; i < TC_BITMASK + 1; i++)
                netdev_set_prio_tc_map(dev, i, qopt->prio_tc_map[i]);

        sch->flags |= TCQ_F_MQROOT;
        return 0;
}

static void mqprio_attach(struct Qdisc *sch)
{
        struct net_device *dev = qdisc_dev(sch);
        struct mqprio_sched *priv = qdisc_priv(sch);
        struct Qdisc *qdisc, *old;
        unsigned int ntx;

        /* Attach underlying qdisc */
        for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
                qdisc = priv->qdiscs[ntx];
                old = dev_graft_qdisc(qdisc->dev_queue, qdisc);
                if (old)
                        qdisc_put(old);
                if (ntx < dev->real_num_tx_queues)
                        qdisc_hash_add(qdisc, false);
        }
        kfree(priv->qdiscs);
        priv->qdiscs = NULL;
}

static struct netdev_queue *mqprio_queue_get(struct Qdisc *sch,
                                             unsigned long cl)
{
        struct net_device *dev = qdisc_dev(sch);
        unsigned long ntx = cl - 1;

        if (ntx >= dev->num_tx_queues)
                return NULL;
        return netdev_get_tx_queue(dev, ntx);
}

static int mqprio_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new,
                        struct Qdisc **old, struct netlink_ext_ack *extack)
{
        struct net_device *dev = qdisc_dev(sch);
        struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);

        if (!dev_queue)
                return -EINVAL;

        if (dev->flags & IFF_UP)
                dev_deactivate(dev);

        *old = dev_graft_qdisc(dev_queue, new);

        if (new)
                new->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;

        if (dev->flags & IFF_UP)
                dev_activate(dev);

        return 0;
}

static int dump_rates(struct mqprio_sched *priv,
                      struct tc_mqprio_qopt *opt, struct sk_buff *skb)
{
        struct nlattr *nest;
        int i;

        if (priv->flags & TC_MQPRIO_F_MIN_RATE) {
                nest = nla_nest_start_noflag(skb, TCA_MQPRIO_MIN_RATE64);
                if (!nest)
                        goto nla_put_failure;

                for (i = 0; i < opt->num_tc; i++) {
                        if (nla_put(skb, TCA_MQPRIO_MIN_RATE64,
                                    sizeof(priv->min_rate[i]),
                                    &priv->min_rate[i]))
                                goto nla_put_failure;
                }
                nla_nest_end(skb, nest);
        }

        if (priv->flags & TC_MQPRIO_F_MAX_RATE) {
                nest = nla_nest_start_noflag(skb, TCA_MQPRIO_MAX_RATE64);
                if (!nest)
                        goto nla_put_failure;

                for (i = 0; i < opt->num_tc; i++) {
                        if (nla_put(skb, TCA_MQPRIO_MAX_RATE64,
                                    sizeof(priv->max_rate[i]),
                                    &priv->max_rate[i]))
                                goto nla_put_failure;
                }
                nla_nest_end(skb, nest);
        }
        return 0;

nla_put_failure:
        nla_nest_cancel(skb, nest);
        return -1;
}

static int mqprio_dump_tc_entries(struct mqprio_sched *priv,
                                  struct sk_buff *skb)
{
        struct nlattr *n;
        int tc;

        for (tc = 0; tc < TC_QOPT_MAX_QUEUE; tc++) {
                n = nla_nest_start(skb, TCA_MQPRIO_TC_ENTRY);
                if (!n)
                        return -EMSGSIZE;

                if (nla_put_u32(skb, TCA_MQPRIO_TC_ENTRY_INDEX, tc))
                        goto nla_put_failure;

                if (nla_put_u32(skb, TCA_MQPRIO_TC_ENTRY_FP, priv->fp[tc]))
                        goto nla_put_failure;

                nla_nest_end(skb, n);
        }

        return 0;

nla_put_failure:
        nla_nest_cancel(skb, n);
        return -EMSGSIZE;
}

static int mqprio_dump(struct Qdisc *sch, struct sk_buff *skb)
{
        struct net_device *dev = qdisc_dev(sch);
        struct mqprio_sched *priv = qdisc_priv(sch);
        struct nlattr *nla = (struct nlattr *)skb_tail_pointer(skb);
        struct tc_mqprio_qopt opt = { 0 };
        struct Qdisc *qdisc;
        unsigned int ntx;

        sch->q.qlen = 0;
        gnet_stats_basic_sync_init(&sch->bstats);
        memset(&sch->qstats, 0, sizeof(sch->qstats));

        /* MQ supports lockless qdiscs. However, statistics accounting needs
         * to account for all, none, or a mix of locked and unlocked child
         * qdiscs. Percpu stats are added to counters in-band and locking
         * qdisc totals are added at end.
         */
        for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
                qdisc = rtnl_dereference(netdev_get_tx_queue(dev, ntx)->qdisc_sleeping);
                spin_lock_bh(qdisc_lock(qdisc));

                gnet_stats_add_basic(&sch->bstats, qdisc->cpu_bstats,
                                     &qdisc->bstats, false);
                gnet_stats_add_queue(&sch->qstats, qdisc->cpu_qstats,
                                     &qdisc->qstats);
                sch->q.qlen += qdisc_qlen(qdisc);

                spin_unlock_bh(qdisc_lock(qdisc));
        }

        mqprio_qopt_reconstruct(dev, &opt);
        opt.hw = priv->hw_offload;

        if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
                goto nla_put_failure;

        if ((priv->flags & TC_MQPRIO_F_MODE) &&
            nla_put_u16(skb, TCA_MQPRIO_MODE, priv->mode))
                goto nla_put_failure;

        if ((priv->flags & TC_MQPRIO_F_SHAPER) &&
            nla_put_u16(skb, TCA_MQPRIO_SHAPER, priv->shaper))
                goto nla_put_failure;

        if ((priv->flags & TC_MQPRIO_F_MIN_RATE ||
             priv->flags & TC_MQPRIO_F_MAX_RATE) &&
            (dump_rates(priv, &opt, skb) != 0))
                goto nla_put_failure;

        if (mqprio_dump_tc_entries(priv, skb))
                goto nla_put_failure;

        return nla_nest_end(skb, nla);
nla_put_failure:
        nlmsg_trim(skb, nla);
        return -1;
}

static struct Qdisc *mqprio_leaf(struct Qdisc *sch, unsigned long cl)
{
        struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);

        if (!dev_queue)
                return NULL;

        return rtnl_dereference(dev_queue->qdisc_sleeping);
}

static unsigned long mqprio_find(struct Qdisc *sch, u32 classid)
{
        struct net_device *dev = qdisc_dev(sch);
        unsigned int ntx = TC_H_MIN(classid);

        /* There are essentially two regions here that have valid classid
         * values. The first region will have a classid value of 1 through
         * num_tx_queues. All of these are backed by actual Qdiscs.
         */
        if (ntx < TC_H_MIN_PRIORITY)
                return (ntx <= dev->num_tx_queues) ? ntx : 0;

        /* The second region represents the hardware traffic classes. These
         * are represented by classid values of TC_H_MIN_PRIORITY through
         * TC_H_MIN_PRIORITY + netdev_get_num_tc - 1
         */
        return ((ntx - TC_H_MIN_PRIORITY) < netdev_get_num_tc(dev)) ? ntx : 0;
}

static int mqprio_dump_class(struct Qdisc *sch, unsigned long cl,
                         struct sk_buff *skb, struct tcmsg *tcm)
{
        if (cl < TC_H_MIN_PRIORITY) {
                struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
                struct net_device *dev = qdisc_dev(sch);
                int tc = netdev_txq_to_tc(dev, cl - 1);

                tcm->tcm_parent = (tc < 0) ? 0 :
                        TC_H_MAKE(TC_H_MAJ(sch->handle),
                                  TC_H_MIN(tc + TC_H_MIN_PRIORITY));
                tcm->tcm_info = rtnl_dereference(dev_queue->qdisc_sleeping)->handle;
        } else {
                tcm->tcm_parent = TC_H_ROOT;
                tcm->tcm_info = 0;
        }
        tcm->tcm_handle |= TC_H_MIN(cl);
        return 0;
}

static int mqprio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
                                   struct gnet_dump *d)
        __releases(d->lock)
        __acquires(d->lock)
{
        if (cl >= TC_H_MIN_PRIORITY) {
                int i;
                __u32 qlen;
                struct gnet_stats_queue qstats = {0};
                struct gnet_stats_basic_sync bstats;
                struct net_device *dev = qdisc_dev(sch);
                struct netdev_tc_txq tc = dev->tc_to_txq[cl & TC_BITMASK];

                gnet_stats_basic_sync_init(&bstats);
                /* Drop lock here it will be reclaimed before touching
                 * statistics this is required because the d->lock we
                 * hold here is the look on dev_queue->qdisc_sleeping
                 * also acquired below.
                 */
                if (d->lock)
                        spin_unlock_bh(d->lock);

                for (i = tc.offset; i < tc.offset + tc.count; i++) {
                        struct netdev_queue *q = netdev_get_tx_queue(dev, i);
                        struct Qdisc *qdisc = rtnl_dereference(q->qdisc);

                        spin_lock_bh(qdisc_lock(qdisc));

                        gnet_stats_add_basic(&bstats, qdisc->cpu_bstats,
                                             &qdisc->bstats, false);
                        gnet_stats_add_queue(&qstats, qdisc->cpu_qstats,
                                             &qdisc->qstats);
                        sch->q.qlen += qdisc_qlen(qdisc);

                        spin_unlock_bh(qdisc_lock(qdisc));
                }
                qlen = qdisc_qlen(sch) + qstats.qlen;

                /* Reclaim root sleeping lock before completing stats */
                if (d->lock)
                        spin_lock_bh(d->lock);
                if (gnet_stats_copy_basic(d, NULL, &bstats, false) < 0 ||
                    gnet_stats_copy_queue(d, NULL, &qstats, qlen) < 0)
                        return -1;
        } else {
                struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);

                sch = rtnl_dereference(dev_queue->qdisc_sleeping);
                if (gnet_stats_copy_basic(d, sch->cpu_bstats,
                                          &sch->bstats, true) < 0 ||
                    qdisc_qstats_copy(d, sch) < 0)
                        return -1;
        }
        return 0;
}

static void mqprio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
{
        struct net_device *dev = qdisc_dev(sch);
        unsigned long ntx;

        if (arg->stop)
                return;

        /* Walk hierarchy with a virtual class per tc */
        arg->count = arg->skip;
        for (ntx = arg->skip; ntx < netdev_get_num_tc(dev); ntx++) {
                if (!tc_qdisc_stats_dump(sch, ntx + TC_H_MIN_PRIORITY, arg))
                        return;
        }

        /* Pad the values and skip over unused traffic classes */
        if (ntx < TC_MAX_QUEUE) {
                arg->count = TC_MAX_QUEUE;
                ntx = TC_MAX_QUEUE;
        }

        /* Reset offset, sort out remaining per-queue qdiscs */
        for (ntx -= TC_MAX_QUEUE; ntx < dev->num_tx_queues; ntx++) {
                if (arg->fn(sch, ntx + 1, arg) < 0) {
                        arg->stop = 1;
                        return;
                }
                arg->count++;
        }
}

static struct netdev_queue *mqprio_select_queue(struct Qdisc *sch,
                                                struct tcmsg *tcm)
{
        return mqprio_queue_get(sch, TC_H_MIN(tcm->tcm_parent));
}

static const struct Qdisc_class_ops mqprio_class_ops = {
        .graft          = mqprio_graft,
        .leaf           = mqprio_leaf,
        .find           = mqprio_find,
        .walk           = mqprio_walk,
        .dump           = mqprio_dump_class,
        .dump_stats     = mqprio_dump_class_stats,
        .select_queue   = mqprio_select_queue,
};

static struct Qdisc_ops mqprio_qdisc_ops __read_mostly = {
        .cl_ops         = &mqprio_class_ops,
        .id             = "mqprio",
        .priv_size      = sizeof(struct mqprio_sched),
        .init           = mqprio_init,
        .destroy        = mqprio_destroy,
        .attach         = mqprio_attach,
        .change_real_num_tx = mq_change_real_num_tx,
        .dump           = mqprio_dump,
        .owner          = THIS_MODULE,
};
MODULE_ALIAS_NET_SCH("mqprio");

static int __init mqprio_module_init(void)
{
        return register_qdisc(&mqprio_qdisc_ops);
}

static void __exit mqprio_module_exit(void)
{
        unregister_qdisc(&mqprio_qdisc_ops);
}

module_init(mqprio_module_init);
module_exit(mqprio_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Classful multiqueue prio qdisc");