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: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 6128e6f..a91f079 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -623,19 +623,6 @@
}
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 @@
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 @@
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 @@
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 @@
{
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));
}