Let's use TICKS instead of US, so PSCHED_TICKS2NS and PSCHED_NS2TICKS
(like in PSCHED_TICKS_PER_SEC already) to avoid misleading.
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Patrick McHardy <kaber@trash.net> suggested:
> How about making this flag and the warning message (in a out-of-line
> function) globally available? Other qdiscs (f.i. HFSC) can't deal with
> inner non-work-conserving qdiscs as well.

This patch uses qdisc->flags field of "suspected" child qdisc.
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While implementing a TCQ_F_THROTTLED flag there was used an smp_wmb()
in qdisc_watchdog(), but since this flag is practically used only in
sch_netem(), and since it's not even clear what reordering is avoided
here (TCQ_F_THROTTLED vs. __QDISC_STATE_SCHED?) it seems the barrier
could be safely removed.
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Impact: make global function static

Fix the following sparse warning:

  net/sched/sch_api.c:192:14: warning: symbol 'qdisc_match_from_root' was not declared. Should it be static?
Signed-off-by: NHannes Eder <hannes@hanneseder.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The functions gen_new_estimator and gen_replace_estimator can return
errors, but they were being ignored.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After implementing qdisc->ops->peek() there is no more calling
qdisc_tree_decrease_qlen() without rtnl_lock(), so qdisc_list_lock
added by commit: f6e0b239 "pkt_sched:
Fix qdisc list locking" can be removed.
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

nla_nest_start() might return NULL, causing a NULL pointer dereference.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After implementing qdisc->ops->peek() and changing sch_netem into
classless qdisc there are no more qdisc->ops->requeue() users. This
patch removes this method with its wrappers (qdisc_requeue()), and
also unused qdisc->requeue structure. There are a few minor fixes of
warnings (htb_enqueue()) and comments btw.

The idea to kill ->requeue() and a similar patch were first developed
by David S. Miller.
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

With feedback from Patrick McHardy.
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Some code here depends on CONFIG_KMOD to not try to load
protocol modules or similar, replace by CONFIG_MODULES
where more than just request_module depends on CONFIG_KMOD
and and also use try_then_request_module in ebtables.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use qdisc_root_sleeping_lock() instead of qdisc_root_lock() where
appropriate. The only difference is while dev is deactivated, when
currently we can use a sleeping qdisc with the lock of noop_qdisc.
This shouldn't be dangerous since after deactivation root lock could
be used only by gen_estimator code, but looks wrong anyway.
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While passing a qdisc root lock to gen_new_estimator() and
gen_replace_estimator() dev could be deactivated or even before
grafting proper root qdisc as qdisc_sleeping (e.g. qdisc_create), so
using qdisc_root_lock() is not enough. This patch adds
qdisc_root_sleeping_lock() for this, plus additional checks, where
necessary.
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These pointers are RCU protected, so proper primitives should be used.
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

During dev_graft_qdisc() dev is deactivated, so qdisc_root_lock()
returns wrong lock of noop_qdisc instead of qdisc_sleeping.
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Acked-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since some qdiscs call qdisc_tree_decrease_qlen() (so qdisc_lookup())
without rtnl_lock(), adding and deleting from a qdisc list needs
additional locking. This patch adds global spinlock qdisc_list_lock
and wrapper functions for modifying the list. It is considered as a
temporary solution until hfsc_dequeue(), netem_dequeue() and
tbf_dequeue() (or qdisc_tree_decrease_qlen()) are redone.

With feedback from Herbert Xu and David S. Miller.
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Acked-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

dev_deactivate() can skip rescheduling of a qdisc by qdisc_watchdog()
or other timer calling netif_schedule() after dev_queue_deactivate().
We prevent this checking aliveness before scheduling the timer. Since
during deactivation the root qdisc is available only as qdisc_sleeping
additional accessor qdisc_root_sleeping() is created.

With feedback from Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit 1cfa2666.

qdisc_destroy() runs fully under RTNL again and not from softint any
longer, so this change is no longer needed.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

...Last block local var got just deleted.
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Based upon reports by Denys Fedoryshchenko, and feedback
and help from Jarek Poplawski and Herbert Xu.

We always either:

1) Never made an external reference to this qdisc.

or

2) Did a dev_deactivate() which purged all asynchronous
   references.

So do not lock the qdisc when we call qdisc_destroy(),
it's illegal anyways as when we drop the lock this is
free'd memory.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Qdisc locks are initialized in the same function, qdisc_alloc(), so
lockdep can't distinguish tx qdisc lock from rx and reports "possible
recursive locking detected" when both these locks are taken eg. while
using act_mirred with ifb. This looks like a false positive. Anyway,
after this patch these locks will be reported more exactly.
Reported-by: NDenys Fedoryshchenko <denys@visp.net.lb>
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Based upon initial discovery and patch by Jarek Poplawski.

The qdisc watchdogs can be attached to any qdisc, not just the root,
so make sure we schedule the correct one.

CBQ has a similar bug.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

From: Jarek Poplawski <jarkao2@gmail.com>

When we are destroying non-root qdiscs, we need to lock
the root of the qdisc tree not the the qdisc itself.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since qdisc_stab_lock is used in qdisc_put_stab(), which is called in
BH context from __qdisc_destroy() RCU callback, softirq safe locking
is needed.
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Based upon bug reports by Stephen Hemminger.

We still had some cases using ->qdisc instead of ->qdisc_sleeping.

Also, qdisc_lookup() should return ingress qdiscs.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Bug reported by Stephen Hemminger.

We need to fetch the root from ->qdisc_sleeping not ->qdisc.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As noticed by Stephen Hemminger, the root qdisc is denoted by
TC_H_ROOT, not zero.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Bug report from Steven Jan Springl:

	Issuing the following command causes a kernel oops:
		tc qdisc add dev eth0 handle ffff: ingress

The problem mostly stems from all of the special case handling of
ingress qdiscs.

So, to fix this, do the grafting operation the same way we do for TX
qdiscs.  Which means that dev_activate() and dev_deactivate() now do
the "qdisc_sleeping <--> qdisc" transitions on dev->rx_queue too.

Future simplifications are possible now, mainly because it is
impossible for dev_queue->{qdisc,qdisc_sleeping} to be NULL.  There
are NULL checks all over to handle the ingress qdisc special case
that used to exist before this commit.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch makes the needlessly global qdisc_class_hash_alloc() static.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Acked-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add size table functions for qdiscs and calculate packet size in
qdisc_enqueue().

Based on patch by Patrick McHardy
 http://marc.info/?l=linux-netdev&m=115201979221729&w=2Signed-off-by: NJussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Idea is from Patrick McHardy.

Instead of managing the list of qdiscs on the device level, manage it
in the root qdisc of a netdev_queue.  This solves all kinds of
visibility issues during qdisc destruction.

The way to iterate over all qdiscs of a netdev_queue is to visit
the netdev_queue->qdisc, and then traverse it's list.

The only special case is to ignore builting qdiscs at the root when
dumping or doing a qdisc_lookup().  That was not needed previously
because builtin qdiscs were not added to the device's qdisc_list.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move the destruction of the old queue into qdisc_graft().

When operating on a root qdisc (ie. "parent == NULL"), apply
the operation to all queues.  The caller has grabbed a single
implicit reference for this graft, therefore when we apply the
change to more than one queue we must grab additional qdisc
references.

Otherwise, we are operating on a class of a specific parent qdisc, and
therefore no multiqueue handling is necessary.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Lock the root of the qdisc being operated upon.

All explicit references to qdisc_tree_lock() are now gone.
The only remaining uses are via the sch_tree_{lock,unlock}()
and tcf_tree_{lock,unlock}() macros.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

And give it it's own lock.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When we have shared qdiscs, packets come out of the qdiscs
for multiple transmit queues.

Therefore it doesn't make any sense to schedule the transmit
queue when logically we cannot know ahead of time the TX
queue of the SKB that the qdisc->dequeue() will give us.

Just for sanity I added a BUG check to make sure we never
get into a state where the noop_qdisc is scheduled.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When code wants to lock the qdisc tree state, the logic
operation it's doing is locking the top-level qdisc that
sits of the root of the netdev_queue.

Add qdisc_root_lock() to represent this and convert the
easiest cases.

In order for this to work out in all cases, we have to
hook up the noop_qdisc to a dummy netdev_queue.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

alloc_netdev_mq() now allocates an array of netdev_queue
structures for TX, based upon the queue_count argument.

Furthermore, all accesses to the TX queues are now vectored
through the netdev_get_tx_queue() and netdev_for_each_tx_queue()
interfaces.  This makes it easy to grep the tree for all
things that want to get to a TX queue of a net device.

Problem spots which are not really multiqueue aware yet, and
only work with one queue, can easily be spotted by grepping
for all netdev_get_tx_queue() calls that pass in a zero index.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Only plain netif_schedule() remains taking a net_device, mostly as a
compatability item while we transition the rest of these interfaces.

Everything else calls netif_schedule_queue() or __netif_schedule(),
both of which take a netdev_queue pointer.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It is always equal to qdisc->dev_queue->lock
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now that our qdisc management is bi-directional, per-queue, and fully
orthogonal, there is no reason to have a special ingress qdisc pointer
in struct net_device.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now qdisc, qdisc_sleeping, and qdisc_list also live there.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>