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Commit af356afa authored by Patrick McHardy's avatar Patrick McHardy Committed by David S. Miller
Browse files

net_sched: reintroduce dev->qdisc for use by sch_api 



Currently the multiqueue integration with the qdisc API suffers from
a few problems:

- with multiple queues, all root qdiscs use the same handle. This means
  they can't be exposed to userspace in a backwards compatible fashion.

- all API operations always refer to queue number 0. Newly created
  qdiscs are automatically shared between all queues, its not possible
  to address individual queues or restore multiqueue behaviour once a
  shared qdisc has been attached.

- Dumps only contain the root qdisc of queue 0, in case of non-shared
  qdiscs this means the statistics are incomplete.

This patch reintroduces dev->qdisc, which points to the (single) root qdisc
from userspace's point of view. Currently it either points to the first
(non-shared) default qdisc, or a qdisc shared between all queues. The
following patches will introduce a classful dummy qdisc, which will be used
as root qdisc and contain the per-queue qdiscs as children.

Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 5b9a9ccf

include/linux/netdevice.h

+3 −0
Original line number Diff line number Diff line
@@ -832,6 +832,9 @@ struct net_device 
	/* Number of TX queues currently active in device  */

	unsigned int		real_num_tx_queues;



	/* root qdisc from userspace point of view */

	struct Qdisc		*qdisc;



	unsigned long		tx_queue_len;	/* Max frames per queue allowed */

	spinlock_t		tx_global_lock;

/*

net/core/rtnetlink.c

+2 −4
Original line number Diff line number Diff line
@@ -606,7 +606,6 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev, 
			    int type, u32 pid, u32 seq, u32 change,

			    unsigned int flags)

{

	struct netdev_queue *txq;

	struct ifinfomsg *ifm;

	struct nlmsghdr *nlh;

	const struct net_device_stats *stats;
@@ -637,9 +636,8 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev, 
	if (dev->master)

		NLA_PUT_U32(skb, IFLA_MASTER, dev->master->ifindex);



	txq = netdev_get_tx_queue(dev, 0);

	if (txq->qdisc_sleeping)

		NLA_PUT_STRING(skb, IFLA_QDISC, txq->qdisc_sleeping->ops->id);

	if (dev->qdisc)

		NLA_PUT_STRING(skb, IFLA_QDISC, dev->qdisc->ops->id);



	if (dev->ifalias)

		NLA_PUT_STRING(skb, IFLA_IFALIAS, dev->ifalias);

net/sched/cls_api.c

+2 −5
Original line number Diff line number Diff line
@@ -168,8 +168,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg) 


	/* Find qdisc */

	if (!parent) {

		struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, 0);

		q = dev_queue->qdisc_sleeping;

		q = dev->qdisc;

		parent = q->handle;

	} else {

		q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
@@ -408,7 +407,6 @@ static int tcf_node_dump(struct tcf_proto *tp, unsigned long n, 
static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)

{

	struct net *net = sock_net(skb->sk);

	struct netdev_queue *dev_queue;

	int t;

	int s_t;

	struct net_device *dev;
@@ -427,9 +425,8 @@ static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb) 
	if ((dev = dev_get_by_index(&init_net, tcm->tcm_ifindex)) == NULL)

		return skb->len;



	dev_queue = netdev_get_tx_queue(dev, 0);

	if (!tcm->tcm_parent)

		q = dev_queue->qdisc_sleeping;

		q = dev->qdisc;

	else

		q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));

	if (!q)

net/sched/sch_api.c

+16 −25
Original line number Diff line number Diff line
@@ -207,7 +207,7 @@ static struct Qdisc *qdisc_match_from_root(struct Qdisc *root, u32 handle) 
static void qdisc_list_add(struct Qdisc *q)

{

	if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS))

		list_add_tail(&q->list, &qdisc_root_sleeping(q)->list);

		list_add_tail(&q->list, &qdisc_dev(q)->qdisc->list);

}



void qdisc_list_del(struct Qdisc *q)
@@ -219,17 +219,11 @@ EXPORT_SYMBOL(qdisc_list_del); 


struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle)

{

	unsigned int i;

	struct Qdisc *q;



	for (i = 0; i < dev->num_tx_queues; i++) {

		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);

		struct Qdisc *txq_root = txq->qdisc_sleeping;



		q = qdisc_match_from_root(txq_root, handle);

	q = qdisc_match_from_root(dev->qdisc, handle);

	if (q)

		goto out;

	}



	q = qdisc_match_from_root(dev->rx_queue.qdisc_sleeping, handle);

out:
@@ -720,9 +714,14 @@ static int qdisc_graft(struct net_device *dev, struct Qdisc *parent, 
			if (new && i > 0)

				atomic_inc(&new->refcnt);



			notify_and_destroy(skb, n, classid, old, new);

			qdisc_destroy(old);

		}



		notify_and_destroy(skb, n, classid, dev->qdisc, new);

		if (new)

			atomic_inc(&new->refcnt);

		dev->qdisc = new ? : &noop_qdisc;



		if (dev->flags & IFF_UP)

			dev_activate(dev);

	} else {
@@ -974,9 +973,7 @@ static int tc_get_qdisc(struct sk_buff *skb, struct nlmsghdr *n, void *arg) 
				q = dev->rx_queue.qdisc_sleeping;

			}

		} else {

			struct netdev_queue *dev_queue;

			dev_queue = netdev_get_tx_queue(dev, 0);

			q = dev_queue->qdisc_sleeping;

			q = dev->qdisc;

		}

		if (!q)

			return -ENOENT;
@@ -1044,9 +1041,7 @@ static int tc_modify_qdisc(struct sk_buff *skb, struct nlmsghdr *n, void *arg) 
				q = dev->rx_queue.qdisc_sleeping;

			}

		} else {

			struct netdev_queue *dev_queue;

			dev_queue = netdev_get_tx_queue(dev, 0);

			q = dev_queue->qdisc_sleeping;

			q = dev->qdisc;

		}



		/* It may be default qdisc, ignore it */
@@ -1291,8 +1286,7 @@ static int tc_dump_qdisc(struct sk_buff *skb, struct netlink_callback *cb) 
			s_q_idx = 0;

		q_idx = 0;



		dev_queue = netdev_get_tx_queue(dev, 0);

		if (tc_dump_qdisc_root(dev_queue->qdisc_sleeping, skb, cb, &q_idx, s_q_idx) < 0)

		if (tc_dump_qdisc_root(dev->qdisc, skb, cb, &q_idx, s_q_idx) < 0)

			goto done;



		dev_queue = &dev->rx_queue;
@@ -1323,7 +1317,6 @@ static int tc_dump_qdisc(struct sk_buff *skb, struct netlink_callback *cb) 
static int tc_ctl_tclass(struct sk_buff *skb, struct nlmsghdr *n, void *arg)

{

	struct net *net = sock_net(skb->sk);

	struct netdev_queue *dev_queue;

	struct tcmsg *tcm = NLMSG_DATA(n);

	struct nlattr *tca[TCA_MAX + 1];

	struct net_device *dev;
@@ -1361,7 +1354,6 @@ static int tc_ctl_tclass(struct sk_buff *skb, struct nlmsghdr *n, void *arg) 


	/* Step 1. Determine qdisc handle X:0 */



	dev_queue = netdev_get_tx_queue(dev, 0);

	if (pid != TC_H_ROOT) {

		u32 qid1 = TC_H_MAJ(pid);
@@ -1372,7 +1364,7 @@ static int tc_ctl_tclass(struct sk_buff *skb, struct nlmsghdr *n, void *arg) 
		} else if (qid1) {

			qid = qid1;

		} else if (qid == 0)

			qid = dev_queue->qdisc_sleeping->handle;

			qid = dev->qdisc->handle;



		/* Now qid is genuine qdisc handle consistent

		   both with parent and child.
@@ -1383,7 +1375,7 @@ static int tc_ctl_tclass(struct sk_buff *skb, struct nlmsghdr *n, void *arg) 
			pid = TC_H_MAKE(qid, pid);

	} else {

		if (qid == 0)

			qid = dev_queue->qdisc_sleeping->handle;

			qid = dev->qdisc->handle;

	}



	/* OK. Locate qdisc */
@@ -1588,8 +1580,7 @@ static int tc_dump_tclass(struct sk_buff *skb, struct netlink_callback *cb) 
	s_t = cb->args[0];

	t = 0;



	dev_queue = netdev_get_tx_queue(dev, 0);

	if (tc_dump_tclass_root(dev_queue->qdisc_sleeping, skb, tcm, cb, &t, s_t) < 0)

	if (tc_dump_tclass_root(dev->qdisc, skb, tcm, cb, &t, s_t) < 0)

		goto done;



	dev_queue = &dev->rx_queue;

net/sched/sch_generic.c

+11 −14
Original line number Diff line number Diff line
@@ -623,19 +623,6 @@ void qdisc_destroy(struct Qdisc *qdisc) 
}

EXPORT_SYMBOL(qdisc_destroy);



static bool dev_all_qdisc_sleeping_noop(struct net_device *dev)

{

	unsigned int i;



	for (i = 0; i < dev->num_tx_queues; i++) {

		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);



		if (txq->qdisc_sleeping != &noop_qdisc)

			return false;

	}

	return true;

}



static void attach_one_default_qdisc(struct net_device *dev,

				     struct netdev_queue *dev_queue,

				     void *_unused)
@@ -677,6 +664,7 @@ static void transition_one_qdisc(struct net_device *dev, 


void dev_activate(struct net_device *dev)

{

	struct netdev_queue *txq;

	int need_watchdog;



	/* No queueing discipline is attached to device;
@@ -685,9 +673,14 @@ void dev_activate(struct net_device *dev) 
	   virtual interfaces

	 */



	if (dev_all_qdisc_sleeping_noop(dev))

	if (dev->qdisc == &noop_qdisc) {

		netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);



		txq = netdev_get_tx_queue(dev, 0);

		dev->qdisc = txq->qdisc_sleeping;

		atomic_inc(&dev->qdisc->refcnt);

	}



	if (!netif_carrier_ok(dev))

		/* Delay activation until next carrier-on event */

		return;
@@ -777,6 +770,7 @@ static void dev_init_scheduler_queue(struct net_device *dev, 


void dev_init_scheduler(struct net_device *dev)

{

	dev->qdisc = &noop_qdisc;

	netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);

	dev_init_scheduler_queue(dev, &dev->rx_queue, &noop_qdisc);
@@ -802,5 +796,8 @@ void dev_shutdown(struct net_device *dev) 
{

	netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);

	shutdown_scheduler_queue(dev, &dev->rx_queue, &noop_qdisc);

	qdisc_destroy(dev->qdisc);

	dev->qdisc = &noop_qdisc;



	WARN_ON(timer_pending(&dev->watchdog_timer));

}