From 6ec1c69a8f6492fd25722f4762721921da074c12 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Sun, 6 Sep 2009 01:58:51 -0700 Subject: net_sched: add classful multiqueue dummy scheduler This patch adds a classful dummy scheduler which can be used as root qdisc for multiqueue devices and exposes each device queue as a child class. This allows to address queues individually and graft them similar to regular classes. Additionally it presents an accumulated view of the statistics of all real root qdiscs in the dummy root. Two new callbacks are added to the qdisc_ops and qdisc_class_ops: - cl_ops->select_queue selects the tx queue number for new child classes. - qdisc_ops->attach() overrides root qdisc device grafting to attach non-shared qdiscs to the queues. Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- net/sched/sch_mq.c | 234 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 234 insertions(+) create mode 100644 net/sched/sch_mq.c (limited to 'net/sched/sch_mq.c') diff --git a/net/sched/sch_mq.c b/net/sched/sch_mq.c new file mode 100644 index 00000000000..c84dec9c8c7 --- /dev/null +++ b/net/sched/sch_mq.c @@ -0,0 +1,234 @@ +/* + * net/sched/sch_mq.c Classful multiqueue dummy scheduler + * + * Copyright (c) 2009 Patrick McHardy + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * version 2 as published by the Free Software Foundation. + */ + +#include +#include +#include +#include +#include +#include +#include + +struct mq_sched { + struct Qdisc **qdiscs; +}; + +static void mq_destroy(struct Qdisc *sch) +{ + struct net_device *dev = qdisc_dev(sch); + struct mq_sched *priv = qdisc_priv(sch); + unsigned int ntx; + + if (!priv->qdiscs) + return; + for (ntx = 0; ntx < dev->num_tx_queues && priv->qdiscs[ntx]; ntx++) + qdisc_destroy(priv->qdiscs[ntx]); + kfree(priv->qdiscs); +} + +static int mq_init(struct Qdisc *sch, struct nlattr *opt) +{ + struct net_device *dev = qdisc_dev(sch); + struct mq_sched *priv = qdisc_priv(sch); + struct netdev_queue *dev_queue; + struct Qdisc *qdisc; + unsigned int ntx; + + if (sch->parent != TC_H_ROOT) + return -EOPNOTSUPP; + + if (!netif_is_multiqueue(dev)) + return -EOPNOTSUPP; + + /* pre-allocate qdiscs, attachment can't fail */ + priv->qdiscs = kcalloc(dev->num_tx_queues, sizeof(priv->qdiscs[0]), + GFP_KERNEL); + if (priv->qdiscs == NULL) + return -ENOMEM; + + for (ntx = 0; ntx < dev->num_tx_queues; ntx++) { + dev_queue = netdev_get_tx_queue(dev, ntx); + qdisc = qdisc_create_dflt(dev, dev_queue, &pfifo_fast_ops, + TC_H_MAKE(TC_H_MAJ(sch->handle), + TC_H_MIN(ntx + 1))); + if (qdisc == NULL) + goto err; + qdisc->flags |= TCQ_F_CAN_BYPASS; + priv->qdiscs[ntx] = qdisc; + } + + return 0; + +err: + mq_destroy(sch); + return -ENOMEM; +} + +static void mq_attach(struct Qdisc *sch) +{ + struct net_device *dev = qdisc_dev(sch); + struct mq_sched *priv = qdisc_priv(sch); + struct Qdisc *qdisc; + unsigned int ntx; + + for (ntx = 0; ntx < dev->num_tx_queues; ntx++) { + qdisc = priv->qdiscs[ntx]; + qdisc = dev_graft_qdisc(qdisc->dev_queue, qdisc); + if (qdisc) + qdisc_destroy(qdisc); + } + kfree(priv->qdiscs); + priv->qdiscs = NULL; +} + +static int mq_dump(struct Qdisc *sch, struct sk_buff *skb) +{ + struct net_device *dev = qdisc_dev(sch); + struct Qdisc *qdisc; + unsigned int ntx; + + sch->q.qlen = 0; + memset(&sch->bstats, 0, sizeof(sch->bstats)); + memset(&sch->qstats, 0, sizeof(sch->qstats)); + + for (ntx = 0; ntx < dev->num_tx_queues; ntx++) { + qdisc = netdev_get_tx_queue(dev, ntx)->qdisc_sleeping; + spin_lock_bh(qdisc_lock(qdisc)); + sch->q.qlen += qdisc->q.qlen; + sch->bstats.bytes += qdisc->bstats.bytes; + sch->bstats.packets += qdisc->bstats.packets; + sch->qstats.qlen += qdisc->qstats.qlen; + sch->qstats.backlog += qdisc->qstats.backlog; + sch->qstats.drops += qdisc->qstats.drops; + sch->qstats.requeues += qdisc->qstats.requeues; + sch->qstats.overlimits += qdisc->qstats.overlimits; + spin_unlock_bh(qdisc_lock(qdisc)); + } + return 0; +} + +static struct netdev_queue *mq_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 unsigned int mq_select_queue(struct Qdisc *sch, struct tcmsg *tcm) +{ + unsigned int ntx = TC_H_MIN(tcm->tcm_parent); + + if (!mq_queue_get(sch, ntx)) + return 0; + return ntx - 1; +} + +static int mq_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new, + struct Qdisc **old) +{ + struct netdev_queue *dev_queue = mq_queue_get(sch, cl); + struct net_device *dev = qdisc_dev(sch); + + if (dev->flags & IFF_UP) + dev_deactivate(dev); + + *old = dev_graft_qdisc(dev_queue, new); + + if (dev->flags & IFF_UP) + dev_activate(dev); + return 0; +} + +static struct Qdisc *mq_leaf(struct Qdisc *sch, unsigned long cl) +{ + struct netdev_queue *dev_queue = mq_queue_get(sch, cl); + + return dev_queue->qdisc_sleeping; +} + +static unsigned long mq_get(struct Qdisc *sch, u32 classid) +{ + unsigned int ntx = TC_H_MIN(classid); + + if (!mq_queue_get(sch, ntx)) + return 0; + return ntx; +} + +static void mq_put(struct Qdisc *sch, unsigned long cl) +{ + return; +} + +static int mq_dump_class(struct Qdisc *sch, unsigned long cl, + struct sk_buff *skb, struct tcmsg *tcm) +{ + struct netdev_queue *dev_queue = mq_queue_get(sch, cl); + + tcm->tcm_parent = TC_H_ROOT; + tcm->tcm_handle |= TC_H_MIN(cl); + tcm->tcm_info = dev_queue->qdisc_sleeping->handle; + return 0; +} + +static int mq_dump_class_stats(struct Qdisc *sch, unsigned long cl, + struct gnet_dump *d) +{ + struct netdev_queue *dev_queue = mq_queue_get(sch, cl); + + sch = dev_queue->qdisc_sleeping; + if (gnet_stats_copy_basic(d, &sch->bstats) < 0 || + gnet_stats_copy_queue(d, &sch->qstats) < 0) + return -1; + return 0; +} + +static void mq_walk(struct Qdisc *sch, struct qdisc_walker *arg) +{ + struct net_device *dev = qdisc_dev(sch); + unsigned int ntx; + + if (arg->stop) + return; + + arg->count = arg->skip; + for (ntx = arg->skip; ntx < dev->num_tx_queues; ntx++) { + if (arg->fn(sch, ntx + 1, arg) < 0) { + arg->stop = 1; + break; + } + arg->count++; + } +} + +static const struct Qdisc_class_ops mq_class_ops = { + .select_queue = mq_select_queue, + .graft = mq_graft, + .leaf = mq_leaf, + .get = mq_get, + .put = mq_put, + .walk = mq_walk, + .dump = mq_dump_class, + .dump_stats = mq_dump_class_stats, +}; + +struct Qdisc_ops mq_qdisc_ops __read_mostly = { + .cl_ops = &mq_class_ops, + .id = "mq", + .priv_size = sizeof(struct mq_sched), + .init = mq_init, + .destroy = mq_destroy, + .attach = mq_attach, + .dump = mq_dump, + .owner = THIS_MODULE, +}; -- cgit v1.2.3 From 23bcf634c8bc0d84607a5b863333191d58baee4c Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Wed, 9 Sep 2009 18:11:23 -0700 Subject: net_sched: fix estimator lock selection for mq child qdiscs When new child qdiscs are attached to the mq qdisc, they are actually attached as root qdiscs to the device queues. The lock selection for new estimators incorrectly picks the root lock of the existing and to be replaced qdisc, which results in a use-after-free once the old qdisc has been destroyed. Mark mq qdisc instances with a new flag and treat qdiscs attached to mq as children similar to regular root qdiscs. Additionally prevent estimators from being attached to the mq qdisc itself since it only updates its byte and packet counters during dumps. Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- net/sched/sch_mq.c | 1 + 1 file changed, 1 insertion(+) (limited to 'net/sched/sch_mq.c') diff --git a/net/sched/sch_mq.c b/net/sched/sch_mq.c index c84dec9c8c7..dd5ee022f1f 100644 --- a/net/sched/sch_mq.c +++ b/net/sched/sch_mq.c @@ -64,6 +64,7 @@ static int mq_init(struct Qdisc *sch, struct nlattr *opt) priv->qdiscs[ntx] = qdisc; } + sch->flags |= TCQ_F_MQROOT; return 0; err: -- cgit v1.2.3